Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Award type：Honored in official journal of a scientific society, scientific journal  Country：Japan

Country：Japan

Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Country：Japan

Award type：Award from publisher, newspaper, foundation, etc.  Country：Japan

Country：Japan

Award type：Honored in official journal of a scientific society, scientific journal  Country：Japan

Country：Japan

Award type：Honored in official journal of a scientific society, scientific journal  Country：Japan

Country：Japan

Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Country：Japan

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>To achieve a decarbonized society, the efficient utilization of biomass resources is gaining attention. However, biomass fuels vary widely in type, each exhibiting different combustion characteristics. Therefore, this study aimed to understand the combustion characteristics of biomass fuels by conducting an overall combustion experiment of biomass under isothermal conditions. As a result, significant differences among the three types of biomasses were not observed. Furthermore, fitting the experimental results to a reaction model for porous particles revealed that the volatile release process could be modeled with a volumetric reaction model, while char combustion could be modeled with a pore model.</p>

DOI： 10.20550/jiebiomassronbun.20.0_11

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Carbon Resources Conversion  

Alkali contents with low melting points in the ash of woody biomass vaporize during the biomass gasification process, damaging various downstream energy conversion devices, such as the solid oxide fuel cells (SOFCs). In this study, the degradation of SOFC anodes by the deposition of potassium compounds (KCl, K2CO3, and KOH) was investigated. An aqueous solution of potassium compounds was dripped onto the anode surface of the SOFC button cell at room temperature. After drying at 343 K, 6.964 × 10-6 mol KCl, 6.964 × 10-6 mol KOH, and 3.482 × 10-6 mol K2CO3 was deposited on the anode. Button cells with the deposition of K compounds were employed for power generation experiments at 1023 K with the supply of artificial syngas from biomass gasification. After the power generation experiments, the surface structures of the anodes were microscopically analyzed using the SEM and EDS. As a result, K compounds hardly affected the OCV of SOFC. With the addition of KCl, no apparent change in the anode structure was observed, and only a slight KCl deposit was detected. However, chloride tends to be chemisorbed on Ni, increasing the ohmic resistance as well as the adsorption/desorption resistance. However, KOH transformed to K2CO3 and then remained massively on the anode, which was clearly observed in the SEM images. K2CO3 significantly decreased the cell voltage under a current density of 100 mA·cm−2. Through impedance analyses, this voltage drop was mainly attributed to the ohmic resistance and gas diffusion resistance. However, there is no evidence that this deposit degrades Ni particles.

DOI： 10.1016/j.crcon.2024.100238

Open Access

Web of Science

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In response to the need for a low-carbon society, the steel manufacturing industry, which is a major producer of carbon dioxide, has introduced hydrogen to replace some fossil fuels. Since the degradation behavior of coke is one of the factors that deteriorate the efficiency of the blast furnace, it is important to understand the degradation behavior of coke during the H₂O gasification process at hydrogen enriched blast furnace. In this study, to find the effect of temperature on degradation behavior between CO₂ gasification and H₂O gasification, gasification experiments were conducted in CO₂and H₂O atmospheres at different temperatures in 20% conversion ratio. Moreover, to investigate the pore behavior, we used the SEM to observe the cross-section of cokes.</p>

DOI： 10.20550/jiesekitanronbun.61.0_2

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Some ash particles in municipal and industrial waste adhere to heat exchanger tube surfaces, which causes problems such as heat-transfer inhibition, high temperature corrosion and low utilization in Waste-to-Energy (WtE) plants. The objective of this study is to develop new surface treatment materials and techniques which can decrease the ash deposition and corrosion. In this paper, the effects of the new material developed were verified on site. The results of the test show that the new material decreased ash deposition and high-temperature corrosion due to molten salts compared to SUS310S.</p>

DOI： 10.20550/jiesekitanronbun.61.0_52

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Biomass generally contains higher potassium and chlorine, compared with coal. Therefore, gaseous KCl generated during combustion adheres on heat transfer tubes due to condensation. However, KCl within ash deposit concentrates at the interface between tube surface and ash deposit layer in Circulating Fluidized Bed (CFB) and/or conventional boilers. In this study, the experiments on KCl condensation, using a compressed ash pellet, showed the feasibility that gaseous KCl penetrated inside the ash deposit and condensed at the surface of heat transfer tubes. Additionally, the effects of S, Si and Ca on Cl deposit were also discussed by lab-scale ash-deposition experiments, using eight samples of coal and biomass fuels. The experimental results showed that both S and Si could reduce Cl condensation, while Ca promoted the Cl deposit on the heat transfer tubes.</p>

DOI： 10.20550/jiesekitanronbun.61.0_22

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Energy  

Co-disposal experiments involving industrial solid waste (ISW) are conducted at a municipal solid waste (MSW) incineration plant in this study, investing the environmental impact of co-disposal with different ISW addition proportions using life cycle assessment (LCA). Results show that increasing ISW proportions improves economic indicators, reducing the payback period from 7.92 years (0 % ISW) to 6.58 years (40 % ISW). Environmental impact indicators initially decrease and then increase. The indicator with the greatest environmental impact is Eutrophication Potential (EP), the only major indicator with positive values in all scenarios when considering power output. Its normalization value reaches a minimum at 30 % ISW blending, at 7.85 × 10−12. Contribution analysis reveals that the direct emissions of N-containing gases are the primary cause, while the addition of urea, ammonia water, and quicklime in flue gas treatment, as well as the ash-slag landfill, also have significant effects. Technical optimization of stepwise co-disposal, denitrification system and ash-slag reduction will be the focus. Compared to the existing conventional situation, the co-disposal system exhibits considerable improvements in environmental benefits and carbon reduction potential. Notably, there is a significant reduction in non-CO2 greenhouse gas emissions. This study offers theoretical insights for multi-source waste disposal in MSW incineration plants.

DOI： 10.1016/j.energy.2024.132322

Web of Science

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Coke, a reducing material in the iron ore reduction process in the ironmaking process, is expected to be depleted in the future, and due to the recent progression of global warming, alternative resources to coke are becoming increasingly important. Therefore, we focused on waste plastic and woody biomass, which are coke-derived wastes, and conducted reduction experiments under N2 atmosphere using a batch-type vertical tube furnace in order to utilize them as reduction material for iron oxide.</p>

DOI： 10.20550/jietaikaiyoushi.33.0_58

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Ash adhesion to the surface of heat-transfer tubes such as slugging and fouling that occurs in waste incinerators and boilers causes problems such as reduction of power generation efficiency, corrosion of heat-transfer tubes, and impediment to safe operation of incinerators. In this study, we investigated a heat-transfer tube material with excellent ash adhesion resistance and corrosion resistance to solve these problems. Specifically, we compared the molten salt formation ratio due to the difference in heat-transfer tube materials by using thermodynamic equilibrium calculation and conducted experiments to measure the contact angle, which is related to the ash adhesion force.</p>

DOI： 10.20550/jietaikaiyoushi.33.0_148

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Hazardous Materials  

A strategy for enhancing value creation from pyrolysis gas and oil, derived from plastic waste, through the generation of two additional outputs of solid carbon and hydrogen was investigated. Three types of hard-to-recycle plastic waste (marine plastic litter, household mixed plastics and cosmetic products packaging) were thermally treated in two stages: (i) decomposition of feedstock into gas and oil via pyrolysis at 600 °C; and (ii) thermolytic conversion of the pyrolysis gas and a fraction of oil into hydrogen and solid carbon at 1300 °C separately. The thermolysis of both pyrolysis gas and oil fractions predominantly resulted in the production of solid carbon (39–70 wt% per plastic feedstock and carbon content of 91.3–98.6 wt%) and H2-rich gas (H2 yield of 5.9–10.8 wt% per plastic waste feedstock and H2 content of 71.4–97.2 vol% per gas volume). The incorporation of pyrolysis oil into the thermolysis process could enhance the outputs of solid carbon and hydrogen. Characterizations of solid carbon and hydrogen obtained from pyrolysis gas and oil fractions were further conducted. The observed similar properties of H2 and solid carbon from pyrolysis gas and oil supported the feasibility of introducing all the pyrolytic products together into the thermolysis process without condensation of oil. To enhance the value of these solid carbon derived from plastics for practical usage, we utilized the obtained solid carbon as a reinforcing agent for polymer composite foam development. The solid carbon reinforced composite foam displayed great abrasion resistance (wear loss: 240 mg), compression strength (0.347 MPa), and dynamic impact properties (energy returned: 124 J/m and energy absorbed: 57.3 J/m), emphasizing the viability of solid carbon as a nucleating agent and reinforcing filler in polymer foam for cushioning applications. Overall, the strategy of pyrolysis-thermolysis, which harnesses both pyrolysis gas and oil, unlocks additional value creation by producing two new outputs from plastic waste. Depending on the market prices for solid carbon and hydrogen, this can substantially change the economics of plastic waste management and create new revenue streams, incentivizing plastic waste collection and processing.

DOI： 10.1016/j.jhazmat.2023.132996

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

<p>In order to decrease ash deposition and hot corrosion in Waste-to-Energy plants, it is necessary to understand mechanisms of the ash deposition and the corrosion, and to develop new solutions. In this study, an adhesion force between an ash pellet and an alloy specimen were firstly measured to investigate the increase mechanisms of the ash deposition and the corrosion, using a tensile testing machine with an electrical furnace. Second, mass loss of the alloy specimens was measured as hot corrosion tests based on Japanese Industrial Standards. Third, phenomenon on the interface was evaluated with production amount of molten salts which were calculated by thermodynamic equilibrium. As a result, the adhesion force and the mass loss of all specimens increased with the interface temperature, and there was exact materials dependency, which indicated that a high chromium content design to improve corrosion resistance was valid also for decrease of the ash adhesion. Moreover, it was observed that mass loss of the alloy specimens with the ash sample collected from an actual boiler had a temperature dependence, and molten salts and accelerated oxidation induced by chlorides attacked the alloy specimens. In addition, generation of HCl gas and molten salts with temperature increase was confirmed with the thermodynamic equilibrium calculations. Judging from these results, starting temperature of the adhesion could be correspond to one which the alloy started to be severely corroded.</p>

DOI： 10.1299/mej.23-00486

Web of Science

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the Combustion Institute  

The gaseous arsenic released from pulverized coal combustion not only poses environmental impacts but also causes the severe poisoning of selective catalytic reduction catalyst. The unclear understanding of the interactions between gaseous arsenic and minerals in coal hinders the arsenic emission control by promoting gaseous arsenic transformation into less troublesome particulate-bound arsenic. To clarify the mechanism of arsenic migration and transformation during pulverized coal combustion, field test, pilot-scale combustion trial, lab-scale adsorption experiment, and molecular-scale theoretical calculation were synergistically conducted in this study. The results demonstrated that the interactions between gaseous arsenic and mineral components included chemical reaction and oxidation process, which began at high temperatures (∼1350 °C) and mainly took place in medium-high temperature region (650∼1350 °C). The metakaolin, magnetite, hematite and anhydrite were found to be active components for the interactions. Among these, anhydrite was the main trapper for gaseous arsenic at high temperatures due to the high thermal stability of calcium arsenate. While metakaolin, magnetite and hematite owned high arsenic adsorption performance in medium-temperature region. In the process of flue-gas cooling, gaseous arsenic tended to be captured by anhydrite thereby forming calcium-bound arsenic at high temperatures, and subsequently reacted with metakaolin, magnetite and hematite by generating iron- or aluminum-bound arsenic as flue gas further cooled down. High flue-gas temperatures and ash components (especially magnetite and hematite) facilitated the arsenic oxidation to hypotoxic arsenate in fly ash. These findings provided the foundation for in-depth control of arsenic emission from coal combustion by promoting arsenic migration and transformation into fly ash.

DOI： 10.1016/j.proci.2024.105467

Web of Science

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the Combustion Institute  

Arsenic release presents a critical environmental pollution issue during municipal solid waste (MSW) incineration. The increase of chlorine-containing waste for incineration processes has heightened interest in the volatilization of heavy metals induced by chlorine. However, the migration and transformation of arsenic, which has a strong affinity for oxygen at high temperatures, are less understood in the context of chlorine influence, leading to the absence of corresponding regulatory strategies. Therefore, this study first investigated the mass distribution of arsenic during co-incineration of MSW and chlorine-rich solid waste (plastics) in a grate incinerator. In addition, Ca3(AsO4)2 was selected as the predominant form of arsenate in the bottom ash to perform decomposition experiments under the influence of HCl, supported by thermodynamic calculations and density functional theory (DFT) calculations. The results demonstrated that chlorine enhances the migration of arsenic from the bottom ash to the fly ash during the co-incineration process. For the first time, it has been discovered that Ca3(AsO4)2 transforms into Ca5(AsO4)3Cl when exposed to HCl at high temperatures, releasing As2O3 (g) into the flue gas. Importantly, the presence of HCl significantly lowers the initial temperature for the release of As2O3 (g). This effect is attributed to the adsorption of chlorine from HCl onto the calcium atoms in Ca3(AsO4)2, which affects the binding energy of adjacent Ca-O-As structure, thereby facilitating arsenic release at lower energies. Furthermore, the initial transformation temperature of Ca3(AsO4)2 into Ca5(AsO4)3Cl is reduced from 1300 °C to 600 °C in a high-chlorine atmosphere, which was obtained by incorporating the thermal properties of Ca5(AsO4)3Cl. These insights are crucial for the understanding of arsenic transformation in high-chlorine environments and offer guidance for arsenic emissions control during the incineration of chlorine-rich solid waste.

DOI： 10.1016/j.proci.2024.105586

Web of Science

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers and The Heat Transfer Society of Japan  

<p>CO₂ biomass gasification is an attractive option for reducing CO₂ emission which produces gas mixtures with higher CO concentrations than typical syngas compositions. However, carbon deposition and catalyst degradation may occur when CO-rich fuel gas is supplied to a Ni-Yttria-stabilized Zirconia solid oxide-based fuel cell. In this study, the electrochemical performance of an SOFC (anode: NiO-YSZ/NiO-GDC) with various CO-rich gas compositions was experimentally investigated. Four distinct gas mixtures were tested using electrochemical experiments at 1073 K. Impedance and steady-state polarization measurements were taken, and electric power generation was assessed at 100 mA·cm^-2 under the 4 gas mixtures. Gas 1, a mixture of H₂ (38%), CO (19%), CO₂ (9.5%), and H₂O (5%) was prepared as a reference gas to model a typical syngas mixture obtained from biomass gasifier. It generated the highest voltage without any degradation of the anode over 8 h. Gas 2, containing CO (19%), CO₂ (9.5%), and H₂O (5%), caused serious anode degradation compared with Gas 1. Gas 3, containing CO (19%) and H₂O (5%) showed good performance with a relatively small polarization resistance and good stability in long-term electric power generation test. Gas 4, consisting of CO (20%) and CO₂ (10%), exhibited the largest charge-transfer resistance at low overpotential and a significant diffusion resistance at high overpotential. Additionally, Gas 4 had the worst stability in the electric power generation test. Based on these results, we conclude that biomass gasification gas is a promising fuel for use in SOFCs. CO direct oxidation can provide electric power generation, although it appears to be unstable and shows high resistance at both low and high overpotentials. H₂O addition can efficiently improve the stability of the CO direct oxidation process.</p>

DOI： 10.1299/jtst.23-00525

Open Access

Web of Science

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

<p>In incinerators and boilers using waste-derived fuels, ash deposition on the surface of heat transfer tubes, such as slugging and fouling, causes problems such as reduced power generation efficiency due to heat transfer inhibition, incinerator operation inhibition, and inhibition of boiler steam temperature and pressure increase due to chemical corrosion on the heat transfer tube surface. In this study, the melting behavior of industrial waste ash was clarified for the practical use of higher temperature and higher pressure steam conditions, and thermal spraying materials were investigated to reduce ash adhesion on the surface of the heat transfer tubes. Contact angle measurement experiments and SEM/EDX analysis were conducted using each material to investigate the ash adhesion resistance and corrosion resistance of the sprayed materials. From the contact angle measurement experiments, it can be considered that the contact angle of the developed material Ni-2 is larger than that of SUS310S under all conditions, and that ash adhesion can be suppressed or reduced. In addition, the results of SEM/EDX analysis suggest that Ni-2 can suppress the progress of chemical corrosion caused by molten ash better than SUS310S.</p>

DOI： 10.14912/jsmcwm.35.0_395

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

<p>Biomass fuel is one of renewable energies and is expected toward a target of net GHG zero emissions in 2050 that Japanese government announced October 2020. Using biomass pellets in pulverized coal fired power plants is recently increasing to reduce CO2 emissions. On the other hands, various types of biomass pellets have been used at many power plants because of requirement by many power suppliers. Recently, not only conifer, but also broad-leaved tree and herbaceous plant have been used for biomass pellets. However, the burning behavior is different for each type of biomass. This study conducted experiments of thermal weight analysis. From the results obtained, the emission characteristics a little bit depend on the biomass types. Some types of the biomass showed two stage’s emission during the volatile matter release. The model of the volatile matter emission was determined.</p>

DOI： 10.1299/jsmepes.2024.28.a113

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Chemosphere  

The rising atmospheric CO2 emissions from the burning of fossil fuels remains a global concern. Mangrove forests, which are important for global biodiversity, are known for their high carbon fixation capacity. However, the characteristics of the pyrolysis and gasification of mangroves remain unclear. Thus, this study focused on mangroves' basic pyrolysis and steam gasification properties for use as a gasification fuel. Three mangrove species: Rhizophora mucronata, Bruguiera cylindrica, and Avicennia marina, were used as experimental samples. In addition, three species of land wood were used for comparison: Eucalyptus, Japanese cedar, and Japanese cypress. In addition to the raw sample, a demineralized sample was used for each sample to account for the influence of the alkali and alkaline earth metals (AAEMs) on pyrolysis and steam gasification. Thermogravimetric analysis was performed to obtain thermogravimetric curves of mangroves and land wood. A laboratory-scale instrument for pyrolysis and gasification using a batch-type horizontal electric furnace was also used at 800 °C in an inert and steam atmosphere. The char yield of raw mangroves was high and independent of the Klason lignin content, suggesting that AAEMs influence char formation during the initial pyrolysis of the mangroves. The results of pyrolysis and gasification under steam atmosphere showed that the H2 production ratio (Steam/Inert) from mangroves was 2.52–5.33, compared to 1.76–2.35 for land woods, the addition of steam significantly enhanced the steam gasification of mangroves. Mangroves contain relatively large amounts of AAEMs, which indicates their potential as a gasification feedstock.

DOI： 10.1016/j.chemosphere.2023.140388

Scopus

PubMed

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Currently, carbon-neutral biomass fuels are attracting attention as an alternative fuel to fossil fuels from the perspective of combating global warming and realizing a sustainable society. However, biomass fuels have the problems of low energy density and high transportation costs. Therefore, we focused on biomass gasification technology. In this study, H₂O gasification experiments were conducted with four different grain size samples using an electrically heated vertical batch furnace to investigate the effect of char grain size on the H₂O gasification behavior of woody biomass char. As a result, there was almost no effect of char particle size on the reaction rate because the reaction proceeds by diffusion of the gasifier into the porous structure of the wood.</p>

DOI： 10.20550/jiebiomassronbun.19.0_25

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In recent years, the primary energy consumption has been incresing globally. Demands for biomass fuels, which are carbon neutral, have been becoming larger. However, biomass fuels have problems such as low energy density and low transportation efficiency. To solve them, biomass gasification has gained broad attention. In this study, we investigated the effect of CO₂ as an oxidant in the gasification reaction of woody biomass. CO₂ gasification experiments were conducted under three conditions with different CO₂ concentrations using an electrically heated drop tube furnace, and the produced gas was analyzed for chemical compositions. As a result, it was found that CO production increased with increase in CO₂ concentration under the experimental conditions while H₂ production decreased.</p>

DOI： 10.20550/jiebiomassronbun.19.0_35

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>As the hydrogen enrichment operation is being considered in the blast furnace to reduce the CO₂ emissions. Since the ash behavior of coke is one of the factors that deteriorate the permeability and stability in the blast furnace, it is important to understand the degradation behavior of coke during the H₂O gasification process. In this study, in order to find the effect of temperature on degradation behavior between CO₂ gasification and H₂O gasification, gasification experiments were conducted in CO₂ and H₂O atmospheres at different temperatures in 20% reaction ratio. Moreover, to investigate the pore behavior, we used the SEM to observe the cross-section of cokes.</p>

DOI： 10.20550/jiesekitanronbun.60.0_2

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Some ash particles in municipal and industrial waste adhere to heat exchanger tube surfaces, which causes problems such as heat-transfer inhibition, high temperature corrosion and low utilization in Waste-to-Energy (WtE) plants. The objective of this study is to develop new surface treatment materials and techniques which can decrease the ash deposition and the corrosion. In this paper, mechanisms of NaCl-induced accelerated oxidation were evaluated through TG-DTA, hightemperature corrosion test, and understanding of reaction kinetics.</p>

DOI： 10.20550/jiesekitanronbun.60.0_58

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In woody biomass or waste to energy plants, high temperature corrosion of boiler tubes, such as active oxidation which is caused by alkali chlorides has become a serious problem. In this study, the active oxidation of metal specimens in the presence of NaCl was evaluated with Thermogravimetry - Differential Thermal Analysis (TG-DTA) to elucidate the mechanisms and establish the highly practical solutions for the corrosion. As a result, the active oxidation had a dependency of the metal composition, and there was a correlation between increments of metal specimens with TG isothermal tests and decrements with immersion corrosion tests.</p>

DOI： 10.20550/jiesekitanronbun.60.0_56

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In recent large-scale pulverized coal-fired power plants, the co-firing of biomass fuels is being promoted to reduce carbon dioxide emissions per unit of power generation. One of the issues related to the biomass co-firing is the deposition and agglomeration of trace components in the boiler. In this study, we focused on silicon compounds as trace components that affect the combustion process. Silicon compounds are simultaneously combusted with biomass fuels, leading to the formation of silica particles, which can adhere to combustion boilers and cause performance deterioration, as well as contribute to atmospheric pollution as particles smaller than PM2.5. Therefore, countermeasures are necessary. The aim of this study is to investigate the combustion characteristics of organic silicon compounds and the behavior of silica particle formation within a pulverized coal combustion boiler. Siloxane, which is might be considered as one of the trace components in biomass, is used as a substitute for silicon compounds, and combustion experiments are conducted using a Drop Tube Furnace (DTF). The analysis of the generated particles provides insights into the formation behavior of silica particles under combustion conditions. When siloxane was combusted using the DTF (Drop Tube Furnace) apparatus, it resulted in the formation of primary particles consisting of white silica particles with amorphous structures at the nanoscale or below.</p>

DOI： 10.20550/jiesekitanronbun.60.0_8

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Recently, the gasification process of woody biomass has been attracting attention to produce renewable gas fuels. However, the gasification process emits tar and soot, which can cause equipment troubles. Therefore, it is necessary to control the formation of tar and soot, and then it is important to elucidate their formation behaviors. This study compared pyrolysis and CO₂ gasification experiments at 950°C and 1100°C, simulating CO₂ gasification by exhaust gas recirculation. Experimental results showed that the addition of CO₂ increased soot formation at 1100°C. It was also observed that H₂ decreases under the same conditions due to the reverse water-gas shift reaction. One of the reasons for the increase in soot formation is that the decrease in H₂ promotes the condensation polymerization of hydrocarbons.</p>

DOI： 10.20550/jietaikaiyoushi.32.0_40

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Ash adhesion to the surface of heat-transfer tubes such as slugging and fouling that occurs in waste incinerators and boilers causes problems such as corrosion of heat-transfer tubes, reduction of power generation efficiency, and impediment to safe operation of incinerators. In this study, we investigated a heat-transfer tube material with excellent corrosion resistance and ash adhesion resistance to solve these problems. Specifically, we compared the molten salt formation ratio due to the difference in heat-transfer tube materials by using thermodynamic equilibrium calculation and conducted ash adhesion experiments by using drop tube furnace.</p>

DOI： 10.20550/jietaikaiyoushi.32.0_114

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>This study focuses on the operation of Ni-YSZ-based SOFC fueled with artificial fuel gas simulating syngas from biomass gasification. H₂, CO, CO₂ and H₂O were mixed to make up artificial fuel gas with various compositions. Electrochemical behaviors were investigated under constant current conditions at 1073K during 8h using Galvano-stat. Cyclic voltammetry was also conducted to assess the stability of SOFC. Measurement results showed that CO₂ and H₂O have significant impacts on power generation performance. In particular, the performance degradation was significant in the absence of CO₂.</p>

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

<p>The non-ferrous smelting industry is accelerating its efforts to expand the processing of recycled materials in order to achieve carbon neutrality, but Top Submerged Lance (TSL) furnace, which play an important role as metal recycling furnace, consume large amounts of coal, which has high CO₂ emissions per unit of heat. The study examined waste circuit boards, waste plastics, waste tyres and biomass fuels as candidates for alternative fuels, and confirmed whether torrefaction of biomass fuels with low calorific value could produce the same calorific value as the fuel used, fuel coal. Sample properties and calorific value after torrefaction of six biomass fuels were compared with fuel coals, showed that all samples had a higher volatile content and a lower fixed carbon content than fuel coal, but the ash content differed from sample to sample. In addition, the torrefaction of both samples significantly increased the calorific value.</p>

DOI： 10.14912/jsmcwm.34.0_295

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Iron and Steel Institute of Japan  

<p>This study aims to investigate the degradation behavior of coke during CO₂ and H₂O gasification reactions. Gasification experiments were conducted in CO₂ and H₂O atmospheres at 1000°C using cokes with different coke reaction indices (CRIs) at 20% reaction ratio. After gasification, the shrinkage ratio in CO₂ gasification was higher than that in H₂O gasification. Moreover, the shrinkage ratio increased with increasing CRI, indicating that the ratio of the surface reaction became larger than that of the internal reaction with increasing CRI at same reaction ratio. The increase value in porosity by gasification reaction decreased with increasing CRI. Owing to the faster diffusion rate of water vapor at 1000°C, water vapor diffuses into the inner part of coke faster, whereas CO₂ gasification reacted from the outer to the inner slowly. Therefore, the increase in porosity of the inner part of coke by H₂O gasification is larger than that by CO₂ gasification. In addition, the degradation behavior in same coke by CO₂ or H₂O gasification did not have obviously difference at same reaction ratio in 1000°C.</p>

DOI： 10.2355/isijinternational.ISIJINT-2023-207

Open Access

Web of Science

Scopus

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Iron and Steel Institute of Japan  

<p>In iron ore sintering plants, the emissions of nitrogen oxides (NO_x) must be reduced. Previous studies have shown that calcium ferrites could significantly reduce NO_x emissions. However, the reaction paths between calcium ferrites and NOx have not been clarified yet. In this study, NO_x reduction tests were conducted at 1073 K–1373 K with a CO/CO₂ ratio of 0.03–0.10. Accordingly, the phase compositions of calcium ferrites before and after NO_x reduction were investigated. CaO·FeO·Fe₂O₃ (CWF), which had a significant effect on NO_x reduction, was formed with a CO/CO₂ ratio of 0.03–0.10. Based on the phase compositions of the calcium ferrites before and after NO_x reduction, we determined that the CWF reduced the amounts of NO_x, and CaO·Fe₂O₃ (CF), 2CaO·Fe₂O₃ (C2F), and Fe₃O₄ are produced from the CWF. The NO_x reduction behavior during coke combustion tests was also investigated. By coating a mixture of iron ore and quicklime around the coke, NOx formation was decreased during coke combustion. This phenomenon may have been caused by the formation of reduced calcium ferrites from a mixture of iron ore and quicklime on the coke surface.</p>

DOI： 10.2355/isijinternational.ISIJINT-2023-210

Open Access

Web of Science

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

<p>Ash adhesion on the surface of heat transfer tubes in incinerators and boilers that use waste-derived fuels causes problems such as reduced power generation performance due to heat transfer inhibition, incinerator operation inhibition, and inhibition of high temperature and high pressure boiler steam generation. In this study, we investigated thermal spraying materials for heat transfer tube surfaces that can reduce ash adhesion. The molten salt formation rate, which is related to the ash adhesion phenomenon, was compared and evaluated for each material using thermodynamic equilibrium calculations, and contact angle measurement experiments were conducted using each material to investigate the ash adhesion resistance of the thermal spraying materials from both computational and experimental aspects. The developed material Ni-2 was found to have significantly lower molten salt formation than the other two materials, and is expected to be an excellent material against high-temperature corrosion. The contact angle of Ni-2 was higher than that of the other substrate, indicating that Ni-2 can inhibit and reduce ash adhesion.</p>

DOI： 10.14912/jsmcwm.34.0_435

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In a blast furnace, coke plays various roles such as supplying a heat source and generating reducing gases such as CO through a gasification reaction. However, with the global warming progresses, it is becoming necessary to reduce CO₂ emissions. To reduce CO₂ emissions, Hydrogen-enriched blast furnace operation is being considered. In this study, in order to find the difference between CO₂ gasification and H₂O gasification, we used the SEM to observe the cross-section of cokes.</p>

DOI： 10.20550/jiesekitanronbun.59.0_6

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Some ash particles in municipal and industrial waste adhere to heat exchanger tube surfaces, which causes problems such as heat-transfer inhibition, high temperature corrosion and low utilization in Waste-to-Energy (WtE) plants. The objective of this study is to develop new surface treatment materials and techniques which can decrease the ash deposition and the corrosion. In particular, mass loss with high-temperature corrosion test and ash adhesion force were measured to provide further understanding of ash deposition mechanisms for various metal surfaces in WtE plants.</p>

DOI： 10.20550/jiesekitanronbun.59.0_84

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In woody biomass or waste to energy plants, high temperature corrosion of boiler tubes, such as active oxidation which is caused by alkali chlorides has become a serious problem. In this study, the active oxidation of metal specimens in a chloride environment was evaluated with Thermogravimetry - Differential Thermal Analysis (TG-DTA) to elucidate the mechanisms and establish the highly practical solutions for the corrosion. As a result, the active oxidation had a dependency of the metal composition, and there was a correlation between increments of metal specimens with TG isothermal tests and decrements with immersion corrosion tests.</p>

DOI： 10.20550/jiesekitanronbun.59.0_82

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Combustion Society of Japan  

<p>Biomass gasification processes are recently attracting attention to produce renewable gaseous fuels as alternatives of fossil fuels. However, raw woody biomass resources to be able to use for biomass gasification are limited because the biomass containing high moisture may lead to low heating values of the gaseous fuels produced, which are inappropriate for the use in gas engines. Then, the introduction of oxygen-enriched air into the gasification reactor has been proposed in this study, which can reduce heat loss during the gasification due to the sensible heat of nitrogen in the gasified gas and increase concentrations of combustible substances in the syngas. Additionally, high partial pressure of oxygen promotes the gasification reaction rates, improving the carbon conversion efficiency. A downdraft packed bed gasifier, which is known to be suitable for small-scale distributed utilization of biomass resources, was selected for woody biomass gasification experiments in this study. After switching the inlet gas from air to oxygen enriched air, the temperature at the top surface of biomass pellet bed rose sharply. The temperature through the packed bed was also kept high under the oxygen enriched air gasification, compared with the normal air gasification. Moreover, the syngas with more H₂ and CO significantly increased. The thermo-equilibrium calculations were conducted to confirm the gaseous compositions and their difference between the air and oxygen enriched air gasification. As a result, the calculation was almost consistent with the experimental results obtained.</p>

DOI： 10.20619/jcombsj.2103

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

CO₂ emissions from ironmaking processes should be reduced to avoid global warming. One promising solution is the effective utilization of organic waste materials in ironmaking processes. In this study, fundamental research on the application of organic waste materials, carbonized municipal waste (CMW) and carbonized woody biomass (CWB), as reducing agents was conducted experimentally to make metal iron from iron oxide. In the reduction experiments of the mixture of iron oxide (Fe₂O₃) with reducing agents (CMW, CWB, coal and graphite), metal iron was obtained with CMW and CWB. This is because the reactivity of fixed carbon in CMW and CWB is higher than that in coal and graphite. As a result, CMW and CWB are usable as reducing agents to make reduced iron.

DOI： 10.3985/jjsmcwm.33.11

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

<p>In recent years, low air ratio high temperature combustion has become the mainstream in waste stoker incinerators in order to improve boiler efficiencies, while NO_x generation due to high temperature in the furnace has become a new problem. In this study, the NO_x generation behavior derived from nitrogen in char was evaluated by simulating the char combustion area in the incinerator in the combustion experiment of the biomass char sample by DTF (Drop tube Furnace) using the combustion atmosphere as a parameter. In particular, we focused on the effects of high-concentration H₂O and CO₂ concentrations due to exhaust gas recirculation and confirmed that H₂O contributes to the reduction of NO_x emissions.</p>

DOI： 10.1299/jsmeenv.2022.32.2205-08-04

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Since a large amount of NOx, that is one of air pollutants, arises from coal combustion process, the SCR method is generally applied for coal-fired power stations to reduce NOx emissions. In the SCR method, NH₃ is introduced into the flue gas at De-NOx catalyst, and NOx is reduced to N₂ by catalytic reaction. This De-NOx catalyst is located upstream of the exhaust gas treatment process, and exposed to a lot of soot and dust particles in the flue gas. Previous studies have revealed that the deterioration of De-NOx catalyst is caused by the deposition of the silica compounds on its surface. Then, the adhesion conditions of these silica compounds were experimentally clarified in this study. De-NOx catalyst samples were exposed to siloxane vapor in simulated flue gas. The formation of silica layer on the surface of De-NOx catalyst was observed by SEM/EDX. The experimental results suggested that silica layer became more explicit in gas including impurities, such as SO₂, NH₃, and NO.</p>

DOI： 10.20550/jiesekitanronbun.58.0_8

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>The effects of hydrocarbon-contained in fuel gas on SOFC with Ni-YSZ as anode are evaluated in this study. Low concentration of toluene was mixed with 96.9％ hydrogen and 3.1％ steam to simulate bio-syngas, corresponding to current developments of biomass gasification technology. Power generation performance was investigated under Galvano-static-mode with toluene concentrations from 0 mg/Nm³ to 1900 mg/Nm³ at 850°C for 30 hours. Impedance spectroscopy under OCV conditions was also conducted to assess SOFC’s internal resistance. As the result, SOFC shows a good stability and generation performance without toluene exposure. However, the voltage decreases even under a low concentration of 380 mg/Nm³ while keeping current density constant at 200 mA/cm². Furthermore, this degradation tends to be serious as concentration of toluene increases. Dramatic voltage drop and visible carbon deposition should not be insignificant when toluene’s concentration was 1900 mg/Nm³. This performance loss seems to be recovered to a certain extent without serious structure destruction on anode.</p>

DOI： 10.3775/jie.100.169

Open Access

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

Web of Science

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In recent years, biomass gasification technology has been attracting more and more attention as an environmentally friendly biomass conversion technology. Biomass char gasification is the most important step of the overall operation of biomass gasification. The char gasification reaction is the limiting step in the global gasification reaction and is of major importance in designing biomass gasifier. In this study, biomass char gasification experiments in H₂O, CO₂ and their mixtures were carried out in a batch type vertical tube furnace. The gasification characteristics and temperature dependence of biomass char in various gasifying agents were experimentally investigated. We also studied the mixed atmosphere gasification and found the char reactivity in a mixed atmosphere of steam and carbon dioxide can be expressed as the sum of the individual reactivity obtained in single atmosphere gasification experiments.</p>

DOI： 10.20550/jietaikaiyoushi.30.0_38

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Oxy-fuel combustion has drawn attention all over the world as useful technique to achieve carbon dioxide capture and storage (CCS). This technology enriches CO₂ in exhaust gas by the flue gas recirculation with adding pure oxygen to combustion atmosphere, which makes easy to capture CO₂ for CCS. Meanwhile, bubbling fluidized bed (BFB) combustion has advantages of high combustion efficiency due to its homogeneous particle mixing and temperature. However, there are few studies of BFB boiler with oxy-fuel combustion system focusing on the formation mechanism of sulfur oxides such as SO₂ and SO₃. In this study, we focused on the mechanism of sulfur oxides formation under oxy-fuel BFB combustion. We conducted lab-scale BFB coal combustion experiment under air, CO₂-O₂, and oxy-fuel conditions, and measured SO₂, SO₃ and NO emissions in flue gas. Then, we compare the formation behaviors and reaction mechanisms of sulfur oxides and nitrogen oxide under those three atmospheres.</p>

DOI： 10.20550/jietaikaiyoushi.30.0_122

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Woody biomass is attracting attention as an alternative energy to fossil fuels. The use of woody biomass is expected to expand in the future. In order to use biomass efficiently as a fuel, it is necessary to clarify its combustion characteristics. Therefore, in this study, in order to clarify the combustion characteristics of biomass, a biomass combustion experiment was conducted using a bubble fluidized bed. Palm Kernel Shell (PKS) was used as an experimental sample. The effect of temperature on the combustion behaviors of biomass was experimentally considered.</p>

DOI： 10.20550/jiebiomassronbun.16.0_19

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Operational problems in biomass-fired boilers include ash deposition to heat transfer tubes and corrosion of heat transfer tubes. Therefore, in this study, we focused on potassium compounds in biomass and conducted an ash deposition experiment using an electrically heated drop tube furnace. In the experiment, potassium-containing mineral (K-feldspar) was used as simulated ash. The amount of ash deposition in various atmospheres was measured. The cross section of samples was observed and analyzed by SEM-EDX, and the atmosphere dependence of the ash deposition characteristics was experimentally considered.</p>

DOI： 10.20550/jiebiomassronbun.16.0_21

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers and The Heat Transfer Society of Japan  

<p>When the biomass gasifier is connected with a gas engine system directly, tar should be removed from the syngas to prevent the engine from breaking down. A downdraft packed bed gasifier has the advantage for low tar emission because the syngas passes through the char gasification zone downstream of the reactor, where tar compounds can be trapped and decomposed. Then, objective of this study is to confirm the tar decomposition behaviors inside the downdraft packed bed reactor. Woody biomass gasification experiments were carried out, using an auto-thermal downdraft packed bed gasifier. The reactor’s height and inner diameter were 1000mm and 100mm, respectively. Black pine pallets were continuously fed into the reactor from the top. The gasifying agent was air, which was introduced into the reactor at the air-fuel equivalent ratio of 0.49. The packed bed height was kept to be constant at 600mm. The reactor has eleven thermo-couples and eleven sampling ports at the wall along the flow direction. They were used for measurements of temperature profiles and gas compositions in the reactor. Micro-GC was used for the measurement of N₂, O₂, CO, CO₂ and H₂, and FIDGC was used for other hydrocarbons. In some ports among them, tar in syngas was also sampled via dichloromethane scrubbing in ice-bath, and analyzed for molecular weight distributions of tar compounds by TOF-MS. As a result, tar and larger hydrocarbons were confirmed to be generated in the upstream, and then decomposed downstream inside the downdraft reactor.</p>

DOI： 10.1299/jtst.2021jtst0034

Web of Science

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

<p>It is important to use combustible waste products as sustainable energy resources for reducing the usage of fossil fuels. One of the simplest ways to do that is the thermal recycling, in which waste products are burned in boilers to drive steam turbines and so on. To design boilers with high efficiencies and low environmental impacts, the residence time for char burnout in combustion zone should be appropriately estimated for each solid fuel. Sewage sludge accounts for 20% of industrial waste products discharged in Japan, although the large part of it is just incinerated without thermal recycling. Then, the objective in this study is to investigate fundamental combustion behaviors of sewage sludge as a solid fuel, in particular, to estimate char burnout in sewage sludge combustion, compared with other solid fuels like woody biomass. Thermo-gravimetrical analysis was combined with iso-thermal combustion experiments of dried sewage sludge samples. Effects of temperature and oxygen concentration were examined, and experimental results were analyzed based on reaction kinetics.</p>

DOI： 10.1299/jsmeenv.2021.31.309

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.32.0_251

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.32.0_409

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Carbon Resources Conversion  

Tar catalytic removal by char is a promising technology for gasification process because of its porous structure, good catalytic activity, low cost, and easy to treatment after deactivation. To provide comprehensive information on the tar catalytic removal by char, this study focuses on the ongoing efforts and advances from fundamental researches to the industrial applications. The tar removal efficiency by char much depends on reaction conditions and char property, such as char origin, porous structure, the functional group on char surface, carbon structure, and AAEM components. The typical reaction kinetics, reaction mechanism, and the deactivation, will be introduced. Then, for the different gasification processes, the potential or typical applications of tar removal by char are discussed and compared. Finally, a comprehensive analysis and improvement in scaling up, commercializing tar removal technologies and integrating the gasification process, are also evaluated and analyzed in this review.

DOI： 10.1016/j.crcon.2019.12.001

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.31.0_227

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

An incineration process is the most dominant method of the waste disposal in Japan. A stoker furnace incinerator is widely used for the waste incineration. In the stoker furnace incinerator, waste products can be sufficiently stirred and burned completely. Recently, low air ratio and high temperature incineration have been applied to the stoke furnace incinerator to improve efficiencies of power generations. However, they result in the increase in the amount of air pollutant NOx due to their higher flame temperatures. In addition, Exhaust Gas Recirculation (EGR) system, which is also applied into advanced incinerators, makes the NOx formation more complicated. In this research, NOx and other gaseous emissions from RDF char combustion were experimentally analyzed, investigating effects of exhaust gas compositions on NOx formations.

DOI： 10.1299/jsmeenv.2020.30.304

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In recent years, biomass gasification processes are attracting attention to produce renewable gaseous fuels. However, it is difficult to use raw biomass because it has low heating values. So, we considered the introduction of oxygen enriched air. By supplying oxygen-enriched air, the heat loss due to water evaporation can be compensated. It is considered that partial combustion of the fuel can be promoted and sufficient heat can be obtained. In the experiments, we used a packed bed gasifier. This gasifier is small in size and suitable for small-scale distributed utilization of biomass. From the experimental results, it was found that even if moisture content of the wet biomass is high, the gasification of the biomass is possible by increasing the oxygen concentration of the gasifying agent. The syngas contained more H₂ and CO compared with normal biomass gasification.</p>

DOI： 10.20550/jiebiomassronbun.15.0_31

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In recent years, due to problems of fossil fuel depletion and global warming, biomass has attracted attention as an alternative energy source. So we focused on biomass gasification. In this study, gasification experiments of three types of biomass are conducted as preliminary experiments of gasification by packed bed gasifier. Assuming that the gas produced when each sample burns completely is assumed as a gasifying agent, the mass loss and gas yield of the sample during gasification were measured.</p>

DOI： 10.20550/jietaikaiyoushi.28.0_248

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Biomass is attracting attention as an alternative energy of fossil fuel. It is expected that the use of woody biomass will increase in the future. In order to use biomass efficiently as fuel, it is necessary to clarify its combustion characteristics. So, in this study, in order to clarify the combustion characteristic of biomass, pyrolysis and combustion experiment during the temperature rising process of two kinds of biomass were conducted by using the thermogravimetric analyzer. Two kinds of woody biomass were used as experimental samples. The effects of mixing each biomass on the combustion behavior of woody biomass were discussed.</p>

DOI： 10.20550/jietaikaiyoushi.28.0_262

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：12th Asia-Pacific Conference on Combustion, ASPACC 2019  

The effective utilization of sub-bituminous coals has been extended as an energy source for power generation because of their low cost and long minable years. However, sub-bituminous coal may undergo spontaneous combustion owing to high reactivity with oxygen in low-temperature air compared with bituminous coal. Therefore, the objective of this study is to elucidate the low-temperature oxidation behaviors of sub-bituminous coal. In particular, transition from oxygen chemisorption to low-temperature oxidation of sub-bituminous coal has been experimentally examined in detail. Isothermal gravimetric analyses are conducted for several bituminous and sub-bituminous coal samples at temperatures varying between 356 K and 476 K in oxygen-enriched air. The chemical compositions of emission gas are continuously monitored under low-temperature oxidation conditions. The experimental results show that the mass of all tested coals, including those of bituminous and sub-bituminous coals, increases at temperatures below 426 K as a result of oxygen chemisorption. At 476 K, the mass of sub-bituminous coal increases slightly with low H2 and CO2 emissions at the beginning and subsequently decreases with high CO and CO2 emissions. This mass change indicates that the transition from oxygen chemisorption to low-temperature oxidation occurs during this period.

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

<p>Low temperature combustion due to dilution of intake air using inert gas is one of the effective methods for heat loss reduction of the engine. However, the combustion velocity almost decreases due to high dilution and that is the reason why a misfire occurs. To prevent the misfire due to reduction of the combustion velocity, application of a biomass gasified gas containing both hydrogen and inert gas to dilution was proposed. Dilution gas in which hydrogen was added to the inert gas was introduced into the engine. And it was suggested that the efficiency be improved.</p>

DOI： 10.1299/jsmemecj.2019.j07108p

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

An incineration process is the most dominant method of the waste disposal in Japan. A stoker furnace is widely used for the waste incineration. Recently, in the stoker furnace, low air ratio and high temperature incineration have been applied increasingly. However, they result in the increase in the amount of air pollutant NOx generated due to flame instability. Especially, it is difficult to control NOx production in char combustion. In this research, in order to evaluate the NOx generation mechanisms in char combustion of waste incineration process, RDF char burning experiments were carried out, investigating the combustion behaviors and exhaust gas compositions. The incineration experiments were conducted at different temperatures and gas conditions such as O₂, CO₂, steam, EGR(Exhaust gas recirculation). The char-NOx production behavior showed different behaviors depending on experiment conditions. In particular at the steam gas and EGR conditions, the char-NOx concentration was very high due to the steam gas shift reaction.

DOI： 10.1299/jsmeenv.2019.29.j206

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

DOI： 10.20550/jieenermix.97.6_623

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

Industrial biomass is the byproduct of light-industry, such as spirit lees, herb residue, bagasse and so on. It is not only a kind of biomass resource, but also a serious environmental pollution source. Gasification is promising and attractive because of cleanness, high efficiency and large treating capacity. However, due to high content of moisture, nitrogen, and organic residue, the existing direct gasification process faces challenges, such as low efficiency, large temperature fluctuation and high tar content in fuel gas. So, innovating gasification process and reactor structure become essential and necessary. In this study, a new fluidized bed two-stage (FBTS) gasification process, mainly consisting of a fluidized bed (FB) pyrolyzer and a transport fluidized bed (TFB) gasifier, has been proposed by the Institute of Process Engineering, Chinese Academy of Sciences. This process decouples direct gasification process into two sub-processes, namely feedstock pyrolysis and char gasification. Depending on thermal cracking, partial oxidation and catalytic reforming by char, the produced tar will be removed to a very low level. To research and develop the FBTS gasification process successfully, the synergistic effect of thermal cracking, partial oxidation and catalytic reforming by char was examined systematically on a laboratory FBTS reaction apparatus.

DOI： 10.14912/jsmcwm.29.0_597

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.29.0_301

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

We have developed the technique of numerical simulation which uses the reduced reaction mechanism to predict the combustion behavior in a waste incinerator. In this paper, we newly made the reduced reaction mechanism “N916” (34 species, 76 reactions) for NOx concentration prediction by benchmarking GRI-Mech3.0 (50 species, 326 reactions) which is the typical combustion reaction mechanism. In order to examine the precision of N916, we calculated temperature and NOx concentration distribution in two-dimensional diffusion flame by using N916 and GRI-Mech3.0. The results showed that temperature and NOx concentration distributions were similar and the rate of divergence of NOx concentration value on center axis in the flame was almost 10%. There is a possibility that N916 is able to be used as the substitution for GRI-Mech3.0 in numerical simulation.

DOI： 10.1299/jsmeenv.2018.28.205

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

An incineration process is the most dominant method of the waste disposal in Japan. A stoker furnace is widely used for the waste incineration. Recently, in the stoker furnace, low air ratio and high temperature incineration have been applied increasingly. However, they result in the increase in the amount of air pollutant NOx and greenhouse gas N₂O generated due to flame instability. In this research, in order to clarify the NOx generation mechanisms in the waste incineration, RDF burning experiments were carried out, investigating the combustion behaviors and exhaust gas compositions. Mass reduction of RDF proceeded faster with higher temperature. NOx concentration in exhaust gas was found to decrease with increase in temperature. It might result from the strong reduction atmosphere generated around RDF fuel. In addition, RDF burning simulation was carried out, using elemental reaction kinetics. It was found that most of HCN and NH₃ at high temperature was converted to NO, N₂O and N₂.

DOI： 10.14912/jsmcwm.29.0_309

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetokai.2018.67.528

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

The Minamata Convention on Mercury was adopted in 2013, and regulations on mercury emissions are becoming stricter all over the world. Coal combustion is one of the major mercury emission sources. The majority of mercury emissions from coal combustion is in elemental mercury. This is because elemental mercury is water-insoluble, although oxidized mercury is water-soluble and easily captured by wet scrubbing systems. In this study, we expected the De-NOx catalyst to have a mercury oxidation/capture performance and conducted mercury oxidation/capture experiment using the De-NOx catalyst as a sorbent. In the result, when HCl existed in the atmosphere, the De-NOx catalyst oxidized all of vapor mercury. On the other hand, when HCl existed in the atmosphere, the De-NOx catalyst showed high mercury capture performance. Furthermore, De-NOx catalyst maintained high mercury capture performance at a high temperature (743 K)

DOI： 10.1299/jsmeenv.2018.28.307

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

DOI： 10.20550/jieenermix.96.3_234

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>One of major problems in pulverized coal combustion process is ash deposition which causes corrosion of the heat transfer tube, decrease in the heat exchange rate, blockage of the gas flow path, etc. The properties of ash particle such as particle number, particle diameter and elemental composition are very important factors to predict and control such ash deposition phenomena. Moreover, it is also important to distinguish whether an ash particle is Included Mineral (IM) or Excluded Mineral (EM). In this study, we made the models of single pulverized coal particle in combustion process using the CCSEM data of different carbon conversion and coal types gotten by DTF experiment in authors’ previous study and evaluated properties of ash particles through the simulation.</p>

DOI： 10.20550/jietaikaiyoushi.26.0_256

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.28.0_301

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>To elucidate fundamental combustion behaviors of some solid combustible wastes, the isothermal combustion experiments are carried out, using an electrically heated vertical batch furnace. The effects of the furnace temperature and the oxygen partial pressure in the reaction atmosphere on the combustion behaviors are studied experimentally and kinetically. Comparing the experimental results obtained with the kinetic modelling results, the most optimum kinetic model is proposed for all of the samples employed, and the detail combustion mechanisms are also elucidated quantitatively. As a result, the completion period of the overall combustion decreases with increases of both the furnace temperature and the oxygen partial pressure. The evolution period of volatile matter (VM) is reduced in order from the bituminous coal, the oil coke to the waste plastic of composite materials. While, the reaction period by 95 % of the conversion is shorten in order from the oil coke, the waste plastic of composite materials and the bituminous coal. The reaction model for the oil coke is revealed as the parallel model of the volumetric model with the grain model. For both the waste plastic of composite materials and the bituminous coal, the parallel model the volumetric model of with the pore model agrees well with the respective experimental results. The activation energy of the fixed carbon (FC) combustion for the oil coke is the largest of the three. The activation energy for the waste plastic of composite material is almost the same as that for the bituminous coal. The reaction orders of the oxygen partial pressure for the VM evolution and the FC combustion become almost 0 and 1 for all of the samples, respectively.</p>

DOI： 10.3775/jie.96.167

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Both resources and environmental controls have globally become obvious. Although alternative energy resources should be utilized more and more, it is also necessary to enhance efficient and ecological use of fossil fuels, which have undertaken basis of global energy society. As coal is one of the even-distributed and reasonable fossil fuels worldwide, huge amount of coal has been consumed in economically developed countries, such rising countries as China and India and economically developing countries. As a result, not only tightness of the coal supply, but also increase of load of the global environment have worried in the near future. From the present viewpoint and the future trend, coal must utilize efficiently and ecologically, and another solid fuels, including biomass and solid wastes, must also be recognized as one of the alternative ones. Additionally, development of both the global, ecological and efficient utilization technologies for those solid fuels and the core and component technologies to support them as well as the academic studies to elucidate the mechanisms in the phenomena occurring have been much more important in the near future to sustain the basis of global energy society.</p>

DOI： 10.20550/jieenermix.96.3_236

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>The Minamata Convention on Mercury was adopted in 2013, and regulations on mercury emissions are becoming stricter all over the world. Coal combustion is one of the major mercury emission sources. The majority of mercury emissions from coal combustion is an elemental mercury. This is because oxidized mercury is water-soluble, but on the other hand elemental mercury is water-insoluble. In this study, we expected the De-NOx catalyst to have a mercury oxidation/capture performance and conducted mercury oxidation/capture experiment using the De-NOx catalyst as a sorbent. In the result, when HCl is present in the atmosphere, the De-NOx catalyst oxidized mercury and when HCl is not present in the atmosphere, the De-NOx catalyst showed high mercury capture performance. Furthermore, De-NOx catalyst maintained high mercury capture performance at a high temperature (743 K)</p>

DOI： 10.20550/jietaikaiyoushi.26.0_336

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Among various recovery processes from waste plastics, the gasification with steam addition is one of the promising technologies to reduce unwanted tar and increase the conversion to syngas. In this study, batch furnace experiments of pyrolysis and steam gasification were conducted on three kinds of plastics. Gas, tar and soot and generation behaviors were examined in them. Granular samples of ABS (acrylonitrile butadiene styrene), PC (polycarbonate) and PE (polyethylene) were used as simulated waste plastics. All experiments were duplicated using different sampling trains for gas collections and tar collections. Nitrogen gas was fed into the furnace to achieve an inert atmosphere, and the temperature was raised to 973 K, 1073 K and 1173 K, respectively. 1.2 g of the sample was inserted into the furnace. In the steam gasification experiment, water vapor was entrained by the nitrogen.</p>

DOI： 10.20550/jietaikaiyoushi.26.0_308

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In this study, we conducted coal gasification experiments by electrical drop tube furnace. In the experiments, we used Low Pressure Impactor (LPI) for the particle sampling in different particle size. Captured particles are dissolved in the acid on each particle size and the trace element concentrations of the solutions in the particles are analyzed by ICP-AES. For the consideration of the result of the experiments, we conducted thermodynamic equilibrium calculations. Calculation results support to investigate the chemical compounds of trace elements in the gasification atmosphere.</p>

DOI： 10.20550/jietaikaiyoushi.26.0_260

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Oxy-fuel coal combustion has drawn attention in the world as useful technique to achieve carbon dioxide capture and storage (CCS). It is a technology to enrich CO₂ in exhaust gas by the flue gas recirculation with additional pure O₂ to combustion atmosphere, which makes easy to capture CO₂ downstream. Meanwhile, bubbling fluidized bed coal combustion has advantages of direct de-sulfurization in bed material and reduction of thermal NO_X in low combustion temperature. However, there are few studies of oxy-coal fluidized bed combustion including emission behaviors of SOx and NOx. In particular, SO₃ is of special concern, because the elevated SO₂ and H₂O concentrations in boiler by the flue gas recirculation may promote the formation of SO₃. Objectives of this study are to understand SOx emission behaviors during the oxy-coal fluidized bed combustion under the actual flue gas recirculation condition, compared with those under the air and CO₂-O₂ combustion conditions.</p>

DOI： 10.20550/jietaikaiyoushi.26.0_258

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.28.0_323

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Material Cycles and Waste Management  

Thermal treatment is a promising technology for the fast disposal of hazardous municipal solid waste incineration (MSWI) fly ash in China. However, fly ash produced in grate incinerator (GFA) is rich in CaO and chlorides, which promote the formation of toxic hexavalent chromium [Cr(VI)] and ash agglomeration during the thermal process, inhibiting the thermal disposal of GFA. In this study, sintering characteristics of CaO-rich GFA were improved by adding Si/Al-rich MSWI ash residues. According to the results, ash agglomeration was well suppressed during thermal treatment of the mixed ash. Si/Al/Fe-compounds competed with un-oxidized Cr-compounds to react with CaO and suppressed Cr(VI) formation. Meanwhile, chlorides in GFA facilitated heavy metal volatilization from added ashes to the secondary fly ash, favoring the recovery of these metals. Ca-aluminosilicates was found as the main mineral phase in the thermally treated mixed ash, which has attractive potential for applications. The formation of the aluminosilicates made the heavy metals that remained in the treated mixed ash more stable than the thermally treated single ash.

DOI： 10.1007/s10163-014-0341-z

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Combustion Society of Japan  

<p>In this study a series of steam gasification experiments were performed on three thermoplastics - Acrylonitrile butadiene styrene (ABS), Polycarbonate (PC) and Polyethylene (PE), in a batch reactor. The effects of steam flow rate and reactor temperature (600～1000℃.) on the amount of tar, soot and char have been studied. The results were then compared with those of Pyrolysis, from our previous study. In addition time of flight mass spectrometry (TOF-MS) analysis was performed to identify the fingerprints of several different tars. It was found out that steam addition has varying effects on each of the studied polymers. It had a positive effect on soot reduction in the case of ABS and PE; tar reduction in PE; and some char reduction in PC. Temperature increase was found to decrease the relative amount of tar while increasing char production. According to the TOF-MS data, the average molecular weight of tar increases with temperature increase.</p>

DOI： 10.20619/jcombsj.58.186_234

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

<p>In order to incinerate heterogeneous fuel such as waste products completely, high excess air ratio was traditionally applied to the burning zone in the incinerator. However, from viewpoints of heat recovery efficiency and flue gas treatment, low excess air ratio at high temperature has been becoming more popular for the waste incinerator year by year. Meanwhile, technologies for NOx emission control should be stricter since high temperature and flame instability under low excess air incineration conditions intend to extend NOx formation. In this study, initial pyrolysis behaviors of wastes in their incineration processes were analyzed to investigate their contributions to NOx formations.</p>

DOI： 10.1299/jsmeenv.2016.26.304

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

<p>Recently, the issue of global environment becomes worse and it is caused by greenhouse gas such as carbon dioxide. Woody biomass attracts attention since it is a renewable energy source and carbon-neutral. One of the promising methods for energy conversion from woody biomass is gasification technology. The purpose of this study is to clarify the gasification behavior of woody biomass and formation/decomposition behavior of tar in the packed-bed gasifier. Gasification experiments (downdraft gasification) were carried out by using the packed-bed gasifier. In this study, pellets of black pine were fed intermittently and using air as the gasification agent. In the gasification experiments, the temperature distribution and the gas compositions in the gasifier were measured during gasification, and the amount of tar in the gasified gas was measured.</p>

DOI： 10.1299/jsmepes.2016.21.e224

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Some ash particles in solid wastes adhere on the heat exchanger tube surfaces inside incinerators. The ash deposition may cause such troubles, heat transfer inhibition, operational problems and high temperature corrosion. The authors have conducted the fundamental research for a surface treatment technology, using a thermal spray coating technique to reduce the deposition and the corrosion. First, this paper reviewed the previous studies on the deposition and the corrosion, such as characteristics of wastes, formation of ash and mechanisms in the incinerators. Then, the corrosion mechanisms were reported by means of our analysis and thermo-equilibrium calculations of the interfaces between the tube surface and the deposition. Moreover, the recent countermeasures against the ash deposition and the hot corrosion were reviewed, and their effectiveness and feasibilities were evaluated.</p>

DOI： 10.3775/jie.95.1089

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

Japan generates about 1 million kL of used lubricant oil annually, only 2 % of which is recycled as regenerated oil. The method presented in this report using solvent extraction with membrane separation produces few residual products : only impurities remaining in a membrane rubber bag. For this study, a continuous regeneration system was set up and operated with two waste lubricant oil samples. The oil recovery rate was estimated over time. Oil quality was tested before and after regeneration processing. Sulfur contents, carbon residue, viscosity at 40 °C, carbon number distribution, and water content were analyzed to assess the oil quality. Continuous regeneration up to 15 h was achieved. The regenerated base oil quality was confirmed, showing no degradation during 15 h extraction.

DOI： 10.3985/jjsmcwm.27.37

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Spectroscopy Letters  

This study describes a measuring system for mass spectrometry, consisting of a glow discharge ionization source for soft plasma ionization and a time-of-flight mass spectrometer, to detect toxic volatile organic compounds rapidly and easily. It is the most important to determine how the complicated fragmentation of such compounds can be suppressed to occur so as to recognize the mass spectra of the volatile organic compounds as their fingerprints. The novelty of this work is that the optimal discharge condition for the soft plasma ionization-time-of-flight mass spectrometer system could be selected, so that the parent mass peak of analyte molecules could be observed both with high sensitivity and with little or no fragmentation of them. Use of air gas at a pressure of 1000 Pa provided the most favorable result for these criteria, whereas, in a previous report, the soft plasma ionization source operating with argon at a pressure of 346 Pa had yielded additional mass peaks of the fragmented species. The reason for this would be explained by the fact that energetic electrons in the plasma, which principally cause the fragmentation of the volatile organic compounds, have lower number density at higher gas pressures, through de-accelerated collisions with the plasma gas.

DOI： 10.1080/00387010.2014.905962

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Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Combustion Society of Japan  

<p>Lignin and cellulose chemicals were used as artificial biomass components to make-up a simulated biomass. Alkali and alkaline earth metal (AAEM) as well as volatile matter contents in these chemicals were much different from each other. Co-gasification of coal with simulated biomass shows improved conversion characteristics in comparison to the average calculated from separate conversion of coal and simulated biomass. Two conversion synergetic peaks were observed whereby the first peak occurred around 400 °C while the second one occurred above 800 °C. Although co-gasification of coal with lignin that has high AAEM content also shows two synergy peaks, the one at higher temperature is dominant. Co-gasification of coal with cellulose shows only a single synergy peak around 400 °C indicating that synergy at low temperature is related with interaction of volatiles. Investigation of morphology changes during gasification of lignin and coal, suggests that their low reactivity is associated with their solid shape maintained even at high temperature.</p>

DOI： 10.20619/jcombsj.57.179_21

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

The iron making process, especially pig iron making process discharges the huge amount of CO_2 because coke made from coal is used as a reductant. For this reason, steel industry discharges the largest amount of CO_2 and it occupies about 13% in Japanese emission. This paper focused the woody biomass substitute for coke in pig iron making process and studied reduction characteristics of iron oxide when heated iron oxide and woody biomass mixed sample in N_2 atmosphere. In addition, we aim to clarify the reduction characteristics of iron oxide by volatile matters in woody biomass.

DOI： 10.20550/jiebiomassronbun.9.0_62

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Energy and Fuels  

Integrated coal gasification combined cycle is expected to play an important role as one of a number of highly efficient conversion technologies for carbonaceous resources. However, it is vital to remove as much H 2S and COS as possible. Our previous study suggested that the molten alkali carbonates of 43 mol of Na2CO3 + 57 mol of K 2CO3 can completely adsorb them at 1173 K to form alkali sulfides. Furthermore, to enhance the overall efficiency in the gasification system, the regeneration characteristics of the used alkali carbonates should be studied. Therefore, the current study works on that issue. The optimum regeneration condition for experiments was estimated by chemical equilibrium software, FactSage 6.2, prior to the regeneration experiments. Chemical equilibrium calculations suggested that a mixture of carbon dioxide and steam could regenerate the used alkali carbonates. The experiments were conducted in an electrically heated tube reactor using a mixture of CO2 and steam as the regeneration agent. As a result, the remaining sulfur in solid after regeneration experiments was around 5 mass % of the total sulfur content in the raw sample at an optimum temperature range of 650-773 K. It is expected that around 95% of alkali sulfides was converted back to alkali carbonates. © 2013 American Chemical Society.

DOI： 10.1021/ef400219q

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Fuel  

Some ash particles in solid fuels adhere on heat exchanger tube surfaces inside coal and/or biomass combustion boilers. The authors have already proposed a surface treatment on tubes, using a thermal spraying technique, to reduce ash deposition. Understanding reduction mechanisms of the ash deposition is necessary to evaluate effects of the surface treatment technique on the reduction of ash deposition. The reduction mechanisms of the ash deposition were elucidated due to physical and chemical aspects, measuring adhesion forces between the ash particles and some alloy specimens of the tube at high temperature under the simulated boiler conditions. As a result, the adhesion force increased with time and depended on both the ash types and the alloy specimens. The thermal spraying of Ni-alloy, in particular, could reduce the adhesion force. Moreover interface reactions between the ash particles and the alloy specimen played an effective role in increasing the adhesion force, alkali metal compounds in the ash samples also related to an increase of the adhesion force. Fe, which was one of the main alloy elements, diffused into the ash deposition layer beyond the interface. This observation result suggested that the interface reactions of the ash particles with the alloy caused an increase of the adhesion force. © 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fuel.2012.11.017

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Fuel  

Effective utilization of biomass materials as a reducing agent in the ironmaking process is one of the key technologies for environmental protection. In this work, in order to study the possibility of effective use of woody biomass as a reducing agent in the carbon composite method, we carried out experiments of the thermal decomposition of woody powder and reduction of mixture of woody powder and iron oxide. Conversion ratio into H2 from woody powder was almost the same between thermal decomposition of woody powder and reduction of the mixture sample. Conversion ratio into CO by reduction was larger than that by thermal decomposition. The final reduction degrees of mixture samples at the temperature from 1273 to 1573 K were 100%. © 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fuel.2010.09.019

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：30th Annual International Pittsburgh Coal Conference 2013, PCC 2013  

The purpose of this study is to examine the gravity shedding mechanisms of ash deposits experimentally. A horizontal furnace, which could simulate the temperature profile in practical boilers, was used in this experiment. The pulverized coal was burned in this furnace. The typical bituminous coal was selected as a sample coal. The gravity shedding of ash deposits was observed, inserting a water-cooling tube into the furnace during combustion. After the experiments, the cross-sectional surface of the water-cooling tube was analyzed using a scanning electronic microscopy. The ash deposits before shedding were found to be between 2 and 3 mm thick. The ash deposits near the metal surface consisted of ash particles, while the surface of the ash deposits partly consisted of lightly sintered ash particles. After shedding, the remaining ash layer was found to be 500 μm thick on the tube surface.

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Combustion Society of Japan  

<p>According to the supply trend of primary energy resources, the resources of such fossil fuels as oil, natural gas and coal have still been consumed steadily worldwide. Among those fossil fuels, the coal resource has the highest ratio of reserves to production. On the other hand, the global environmental issues have strongly been focused recently. In these points of view, the coal must be utilized efficiently and ecologically as well as carbon neutral resources like biomass and solid wastes should also be utilized more effectively. The coal, biomass and solid wastes are generally categorized as solid fuel. Even for the biomass, it is necessary to convert it high-efficiently and environment-friendly. However, those solid fuels have not only their own structural difficulties, but also compositional diversity. In order to solve those difficulties, the harmonization between the theory or model and the social needs is necessary, and the interdisciplinary cooperation will also be effective.</p>

DOI： 10.20619/jcombsj.55.172_87

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the Combustion Institute  

Boron behavior during coal combustion was studied experimentally and theoretically. Seven types of coal with different boron concentrations were pyrolyzed or burned, using an electrically heated drop tube furnace. In order to understand the effect of coal type on the boron component of ash, chemical equilibrium calculations were made to determine which boron compounds contributed to forming the boron compounds found in the ash particles. Additionally, XAFS analyses were also carried out to evaluate the results obtained by the chemical equilibrium calculations. Some boron compounds in coal were volatilized, and others remained in the molten coal ash after combustion. Both the chemical equilibrium calculations of the boron compounds under the combustion condition and the boron analysis of the ash particles by the XAFS suggested that the boron compound contained in the ash was mainly B 2O3. The boron compounds were concentrated in the molten slag during combustion. The enrichment of boron into the ash as particles was related to the amount of slag formed. The index, (Base/Acid ratio) × (Ash content), correlates well with the volatilization fraction of boron even in the actual power plants. © 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

DOI： 10.1016/j.proci.2012.07.018

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Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In order to enhance net power generation efficiency obtained by pulverized coal fired boilers more, it is necessary to fundamentally develop reduction technologies of ash deposit during operation. The thermal coating technology on surfaces of heat exchanger tubes was applied to reduce the ash deposit during coal combustion in this study. Such several tests as the ash melting experiments at high temperature, the deposition experiments of ash particles and the measurements of deposition force after long-term keeping under the simulated boiler condition were carried out. Consequently, the Ni alloy specimen was selected as the best coating material to control the ash deposit. Finally, that coating material was also tested in practical boilers and showed the good performance on the reduction of ash deposit.

DOI： 10.20550/jietaikaiyoushi.22.0_vi

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.24.0_355

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In recent years, protections of environmental pollution and global warming are most important issues to discuss the world energy use. Efficient and clean use of fossil energy resources in the world has been increasing in importance. Coal is produced all over the world also, and it amount of reserves is larger than any other fossil fuels (oil, natural gas, etc.). Consequently, IGFC (Integrated gasification fuel cell combined cycle) has been attracting attention as one of efficient coal utilization. However, trace elements in coal are emitted to coal syn-gas in vapor phase, and affect fuel cell electrodes to deteriorate their performances. In this study, we assess the effect of trace element in syn-gas on SOFC power generation. We have tested a button cell in 900℃ for about 20 hours with simulated gas doped vapor As and Se.

DOI： 10.20550/jiesekitanronbun.49.0_120

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Cleaner Combustion and Sustainable World - Proceedings of the 7th International Symposium on Coal Combustion  

This study proposes reduction technology of ash deposition on the heat exchanger tube in pulverized coal fired (PCF) boilers. Thermal spraying technique is adopted to change the surface properties of tube to reduce the ash deposition. As a result, Ni alloy as a thermal spraying material played an effective role to reduce the deposition under both the ash deposition experiments and the actual coal combustion experiments. However, it is necessary to change ash types in order to evaluate that the thermal spraying technology is universally useful or not. If this technology will be applied to the commercialized PCF boilers, additionally, the effectiveness for the long-term will also be studied as well as the theoretical elucidation on the reduction of ash deposition must be discussed. In this study, therefore, four types of coal ash with different melting points were tested as samples for the ash deposition experiments. The long-term ash adhesion experiments were also carried out, using a precise tension tester at high temperature. As the theoretical approaches, the compositions of each ash particle depositing on the tube surface were analyzed by a computer-controlled scanning electron microscope (CCSEM) with electron dispersive spectroscopy (EDS) detector, thereby the interfacial reactions between the ash deposition layer and the heat exchanger tube were discussed. Those results obtained were also compared to the results obtained by the thermal equilibrium calculations. © Tsinghua University Press, Beijing and Springer-Verlag Berlin Heidelberg 2012.

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Cleaner Combustion and Sustainable World - Proceedings of the 7th International Symposium on Coal Combustion  

The purpose of this study is to quantitatively evaluate behaviors of ash deposition during combustion of Upgraded Brown Coal (UBC) and bituminous coal in a 145 MW practical coal combustion boiler. A blended coal consisting 20 wt% of the UBC and 80 wt% of the bituminous coal was burned for the combustion tests. Before the actual ash deposition tests, the molten slag fractions of ash calcualted by chemical equilibrium calculations under the combustion condition was adopted as one of the indices to estimate the tendency of ash deposition. The calculation results showed that the molten slag fraction for UBC ash reached approximately 90% at 1523 K. However, that for the blended coal ash became about 50%. These calculation results mean that blending the UBC with a bituminous coal played a role in decreasing the molten slag fraction. Next, the ash deposition tests were conducted, using a practical pulverized coal combustion boiler. A water-cooled stainless-steel tube was inserted in locations at 1523 K in the boiler to measure the amount of ash deposits. The results showed that the mass of deposited ash for the blended coal increased and shape of the deposited ash particles on the tube became large and sperical. This is because the molten slag fraction in ash for the blended coal at 1523 K increased and the surface of deposited ash became sticky. However, the mass of the deposited ash for the blended coal did not greatly increase and no slagging problems occurred for 8 days of boiler operation under the present blending conditions. Therefore, appropriate blending of the UBC with a bituminous coal enables the UBC to be used with a low ash melting point without any ash deposition problems in a practical boiler. © Tsinghua University Press, Beijing and Springer-Verlag Berlin Heidelberg 2012.

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

A process to recover base oil from waste lubricating oil is proposed in this study, which is based on solvent extraction with membrane. In this process, organic solvent is circulated in a closed loop, leading to a resource saving. Residue consists of only impurities in waste lubricating oil, such as suspended particles, aqueous droplets, soot and tar, leading to a waste reducing. This process includes a fractional distillation, too, but it is for separating out organic solvent from oils. Then, temperature for fractional distillation is lower than 100 °C, leading to an energy saving. Rubber film is utilized as membrane, whose polymer network structure works as filter to separate impurities from oil dissolved in solvent. In order to verify the feasibility of this process, effect of extraction period, solvent volume and extraction temperature on both yield and quality of the extracted oil was experimentally estimated.

DOI： 10.1299/kikaib.78.1048

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人日本エネルギー学会  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan  

Objective in this study is to elucidate the fundamental gasification characteristics for carbonaceous resources. Effects of temperature and gaseous agents on the gasification characteristics of carbonaceous materials were experimentally and theoretically studied by the gasification of woody sawdust, using an electrically heated drop tube furnace. Results of the co-gasification of CO2 with H2O were compared by the gasification by a single gaseous agent such as CO2 or H2O. As a result, H2 and CO concentrations increased with an increase of temperature. CO concentration under the co-gasification condition produced more than that under the single gasification condition. The H2 formation showed the opposite tendency to the CO formation during the co-gasification. This synergy effect was also elucidated theoretically by the simulation of reaction kinetics. The simulated temperature indicating the maximum synergy effect on CO formation agreed well with that obtained by the experiments.

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

Pyrolysis and combustion experiments of dried sewage sludge were conducted using an electrically heated drop furnace to elucidate NOx formation/destruction characteristics. When the dried sewage sludge was fed into the drop furnace, the particle temperature rose rapidly and the particles swelled. The char particle structure became balloon-like. Regarding NOx formation, both NO and N<SUB>2</SUB>O were formed during combustion. After N<SUB>2</SUB>O was generated in the flame, NO was produced because N<SUB>2</SUB>O was destroyed by H radicals formed by CO oxidation. Although conversion of fuel-N into N<SUB>2</SUB>O decreased with increased furnace temperature, conversion of fuel-N into NO increased. The N<SUB>2</SUB>O conversion ratio of the dried sewage sludge was higher than that of the sample coal because the dried sewage sludge emits more HCN, which more readily produces N<SUB>2</SUB>O.

DOI： 10.3985/jjsmcwm.21.193

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Iron and Steel Institute of Japan  

Objective in this study is to elucidate the fundamental gasification characteristics for carbonaceous resources. Effects of temperature and gaseous agents on the gasification characteristics of carbonaceous materials were experimentally and theoretically studied by the gasification of woody sawdust, using an electrically heated drop tube furnace. Results of the co-gasification of CO₂ with H₂O were compared by the gasification by a single gaseous agent such as CO₂ or H₂O. As a result, H₂ and CO concentrations increased with an increase of temperature. CO concentration under the co-gasification condition produced more than that under the single gasification condition. The H₂ formation showed the opposite tendency to the CO formation during the co-gasification. This synergy effect was also elucidated theoretically by the simulation of reaction kinetics. The simulated temperature indicating the maximum synergy effect on CO formation agreed well with that obtained by the experiments.

DOI： 10.2355/tetsutohagane.96.150

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：High Temperature Society of Japan  

Sulfur oxides (SO<SUB>x</SUB>) are one of the main sources of acid rain. In a fluidized bed combustor, limestone is a directly supplied into the combustor, as a desulfurizer in order to decrease the emissions of SO<SUB>x</SUB> from fuel, such as sewage sludge and coal. In our previous studies, NaCl-doped limestone has a good performance on the desulfurization characteristics. In the present study, the effect of alkali metal compounds NaCl, KCl and LiCl-dopings on the formation of CaO crystal structure was simulated by the molecular dynamics method. The result indicates that KCl in KCl-doped CaO deforms more largely the CaO crystal structure than NaCl, because K atom tends to separate from Cl atom at high temperature due to larger ionic radius of K than that of Na. For LiCl-doped CaO, LiCl also deforms the CaO crystal structure, because Li, whose ionic radius is smaller than that of Na, can move freely inside the CaO crystal lattice at high temperature. Based on the results obtained by the molecular dynamics simulations, only the NaCl-doping into CaO has a positive effect on the CaO crystallization. Consequently, this NaCl-doping may enhance the desulfurization efficiency. From this viewpoint, the molecular dynamics simulation can well explain the relationship between the desulfurization efficiency of CaO and the effect of alkali metal compounds addition into CaO.

DOI： 10.7791/jhts.36.41

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Particuology  

Some of the heavy metals in coal and wastes vaporize during combustion, concentrate in fine particulates, and emit with the flue gas into the atmosphere, to produce adverse effect on environment and health. This study first investigates the fate of the heavy metal species, especially Pb, Cd and Cr, known as semi-volatile, in various flue gases, especially in the presence of HCl and SO2, by chemical equilibrium calculation, in which, Si and Ca were proposed as base sorbent materials to capture Pb, Cd and Cr. Then Si- and Ca-based compounds as well as waste materials used as sorbents were optimized to capture the heavy metals. Finally, the optimal sorbent was tested in actual burning of dried sewage sludge as solid fuel, to evaluate the effectiveness of the sorbent. Calculated results show that Cl increases the volatility of most heavy metals, while SO2 enhances formation of condensed phases. Among the sorbents tested, kaolin appears most efficient to capture Pb and Cd. For sludge combustion with kaolin addition, both Pb and Cd were shifted from sub-micron to macro-sized particles, and accompanied by considerable decrease of 0.1 μm particles. © 2009.

DOI： 10.1016/j.partic.2009.06.004

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Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In order to control ash deposition on heat exchanger tubes in coal or woody biomass combustion boilers, surface treatment of the tubes, using a thermal spraying technique, was proposed in this study. The ash deposition mechanisms were elucidated, based on physical and chemical aspects, under the condition of long exposure period. First, adhesive force (<I>S<SUB>b</SUB></I>) between ash and alloy surface at high temperature was measured. As the physical aspect, <I>S<SUB>b</SUB></I> increased with an increase of the exposure time and could be predicted by an improved logistic function. Moreover, <I>S<SUB>b</SUB></I> depended on the temperature, so that an interface reaction controlled the increasing rate of adhesive force. As the chemical aspect, the interface between the ash deposition and alloy was observed and analyzed by a SEM-EDS and a FE-EPMA to consider the mechanisms of an increase of the adhesive force. The result showed that S and Na contained in the ash composition diffused into the alloy and that Fe mainly composing of the alloy specimens also diffused into the ash deposition. The diffusion coefficient of Fe into the ash deposition was also calculated by the results of a point elemental analysis. These results suggested that the interfacial reactions of the ash particles with the alloy affected the increase of adhesive force.

DOI： 10.3775/jie.88.816

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Gasification technology is recognized as one of the candidates to utilize the biomass effectively. From this viewpoint, this study focused fundamentals on woody biomass gasification, using a labscale packed-bed. In this experiment, pellets of black pine are gasified, using air as the gasification agent. The gasification tests were carried out under both updraft and downdraft conditions. The temperature distribution inside the gasifier and the compositions of gasified gas were measured and analyzed during gasification by thermo-couples inserted from a furnace wall and a micro gas chromatograph, respectively. The produced gasses before cooling were also sampled to analyze amount of tar generation in the gasses. As a result, the lower heating value of the produced gas under the downdraft condition was higher than that under the updraft condition. It was easier to operate under the downdraft condition than under the updraft. Under the updraft condition, bridging phenomenon happened. Amount of tar generation under the downdraft condition was lower than that under the updraft. This is because tar passes through a partial combustion zone or higher temperature zone in the downdraft gasifier.

DOI： 10.1299/kikaib.75.752_810

Scopus

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In pulverized coal fired boilers, molten ash particles generated during combustion have possibility of adhesion on surface of heat exchanger tubes. This causes problems of heat transfer inhibition such as slagging and fouling as well as boiler trouble on operation. In order to solve this problem, surface treatment technology of the heat exchanger tubes is developed in this study. This paper describes dependence of the adhesive force between the deposition layer and the tube surface on the coal types.

DOI： 10.20550/jiesekitanronbun.46.0_126

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

DOI： 10.14912/jsmcwm.20.0.125.0

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Boron contained in coal are partly released to the flue gas during combustion. Boron are captured in flue gas cleaning systems and the emissions of these elements are generally low. However, it is important to understand the behavior of boron to improve the reliability of the gas cleaning systems. Though a lot of researches examined the behavior of boron, the behavior of these elements in coal combustion has not been clarified in detail yet. In this research, the release behavior of boron from coal was investigated using a drop tube furnace (DTF). As a result, it is thought that a part of the boron would be absorbed in molten slag during combustion.

DOI： 10.20550/jiesekitanronbun.46.0_144

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Welding Society  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：JAPAN WELDING SOCIETY  

A report of the adesion behaviors of ashes on work boiler tubes and some properties of thermal splaying layer, based on the study of the mechanisms of ash adhesion.

DOI： 10.14920/jwstaikai.2008f.0.311.0

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

The role of methanol (MeOH) in the supercritical water oxidation (SCWO) of ammonia (NHs) was investigated near the typical operating conditions of a commercial plant at 560-620°C and 25 MPa using a tubular reactor. It was found that the presence of MeOH strongly affected the reaction behavior of nitrogen. With the addition of MeOH, at concentrations more than twice the initial concentrations of NH3 (1.4-5.7 mmol/mol of the feed mixture), the conversion of NH3 to N2O increased by about four times to 0.5-0.6 compared to that with no MeOH addition. The production of NO3- from NH3 increased in the liquid effluent with a conversion of up to 0.2. The productions of NO2-, NO, and NO2 from NH3 had similar behavior under the presence of MeOH at the tested conditions, and significant effects were observed at MeOH concentrations more than 2-6 times of the initial concentrations of NH3. The experimental results made it clear that NO and NO 2 were produced under the SCWO conditions. Methods for the reduction of N2O and NO3- were also investigated. Results showed that SCWO is not suitable for the decomposition of N2O. Other post-treatment methods such as catalytic decomposition should be applied to reduce N2O in the gas effluent. NO3- reduction methods (e.g., two-step reaction) proposed in this study should also be considered to prevent corrosion of the reactor material. © 2007 American Chemical Society.

DOI： 10.1021/ie070168u

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

The biomass gasification has recently been recognized as one of the candidate technologies to utilize the biomass effectively. In this study, pellets of black pine are gasified in a packed-bed gasifier, using air as gasification agent. In the gasification tests, the temperature distribution in the gasifier and the compositions in the gasified gas are measured and analyzed during gasification by thermo-couples and a micro gas chromatograph, respectively. Fundamental gasification characteristics in the packed-bed were discussed by those results obtained.

DOI： 10.20550/jiebiomassronbun.2.0_88

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Fundamental gasification characteristics in CO_2 and H_2O atmospheres at high temperature are experimentally studied, using an electric heated drop tube furnace. The gasification experiments are performed, changing temperature at the furnace wall, gasification agents and residence time. Hinoki sawdust is selected as a fuel. In the experiments, the gas composition and the elemental compositions in the residual reaction particles are analyzed. The result shows that co-existence of CO_2 with H_2O can enhance the gasification performance, compared with the individual gasification characteristics.

DOI： 10.20550/jiebiomassronbun.2.0_36

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Society of Inorganic Materials, Japan  

DOI： 10.11451/mukimate2000.14.177

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Fuel  

DOI： 10.1016/j.fuel.2005.08.024

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Gasification and pyrolysis characteristics of woody biomass were studied, using an electrically heated drop tube furnace, at 1173K and in CO_2 and N_2 atmospheres, respectively. Hinoki sawdust was selected as one of samples of woody biomass. Under this experimental condition, the gasification conversion and cold gas efficiency attained about 18% and 39%, respectively. The main components of the gaseous species were CO, H_2 and CH_4. The concentrations of those gaseous species in gasification were higher than that in pyrolysis. The main composition of the residue for gasification was fixed carbon. These results suggested that volatile matter in the biomass is easily gasified. The fixed carbon in the biomass was hard to be gasified.

DOI： 10.20550/jiebiomassronbun.1.0_110

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramic Society of Japan  

In this study, the change in the desulfurization characteristics of limestone induced by adding some alkali metal compounds and chlorides to limestone was investigated by thermobalance experiments. In addition, molecular dynamics (MD) simulations were performed to elucidate the effect of alkali-metal chloride additions on the CaO calcination for the desulfurization process. The experimental results obtained show that the addition of NaCl into the limestone is the most effective in improving the desulfurization efficiency. The X-ray diffraction analyses of the calcined seashell, limestone and NaCl-doped limestone found that the calcined seashell, as well as the calcined NaCl-doped limestone, have a similar structure as the CaO crystal. These two materials also show a high desulfurization efficiency. The MD simulations show that NaCl doping into the CaO contributes to the crystallization of CaO, while KCl and LiCl dopings have a small contribution. Therefore, the NaCl doping has a predominant effect on the CaO crystallization leading to a high desulfurization efficiency.<br>

DOI： 10.2109/jcersj.114.676

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In considering effective utilization of low-grade coals with high fixed carbon content, it is necessary to enhance ignition and burnout characteristics by means of adding the supplemental fuels. Co-combustion technologies for low-grade coals with biomass are generally recognized as one of the candidate technologies to enhance these characteristics. Although the biomass addition will affect NO_x emission, the precise NO and N_2O behaviors during co-combustion have not always been elucidated yet. Therefore, this report studies fundamental NO and N_2O formation/decomposition behaviors and their mechanisms experimentally and theoretically. In the simulation, the homogeneous and heterogeneous reaction schemes are considered to elucidate the NO and N_2O formation/decomposition mechanisms precisely. As a result, concentrations of NO and N_2O during co-combustion become almost similar to those during coal combustion, even if the input fuel nitrogen in co-combustion is half of that in coal combustion. The NO and N_2O formation/decomposition mechanisms relate to the heterogeneous reaction scheme. The main elemental reaction is the reaction of NO with char-C to produce CN, which reacts with OH to form NCO. Consequently, the simulation results agree well with the experimental results obtained.

DOI： 10.20550/jiebiomassronbun.1.0_102

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Material Cycles and Waste Management  

This paper studies the fundamental formation characteristics of fine particulates during the wasted oil combustion. The combustion experiments are conducted, using a drop tube furnace with a spray burner of two-phase flow type. The particulate matter in the exhausted gas is collected and classified by a Low Pressure Impactor (LPI) isokinetically. This study focuses on effect of content of residual carbon and Polycyclic Aromatic Hydrocarbons (PAH) in a fuel on the PM formation. The light oil with C-type heavy oil or several types of aromatic hydrocarbons are tested as the simulated waste oils. As a result, particle size distribution of the particulates during light oil combustion at stoichiometric air ratio of 0.8 becomes single-mode with the size between 0.08 and 0.24 mm. The PM collected looks like a tar as precursor of soot particles. The residual carbon and aromatic hydrocarbons in a fuel affect concentration of precursor of soot particles and formation of submicron particles with size between 0.08 and 0.24 mm. Additionally, 3 to 4 rings PAHs are concentrated in the precursor of soot particles.

DOI： 10.14912/jswmepac.17.0.241.0

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Combustion Society of Japan  

DOI： 10.20619/jcombsj.48.144_174

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Fuel  

Current understanding has shown that aluminosilicate- and calcium-based sorbents could be applied to control trace metals emission from combustion and incineration processes. However, the use of industrial commercial sorbents is not always appropriate. The present study dwells on the use of natural and waste materials as sorbents to capture lead and cadmium compounds during combustion. The main task is to optimize the use of those materials by screening them, using a thermobalance. Then, the determined optimum sorbent was tested on an electrically heated drop tube furnace, burning sewage sludge at temperatures ranging from 1073 to 1223 K. The results showed that some of aluminosilicate-based sorbent were more effective than calcium-based sorbents. Kaolin was found to be a relatively effective sorbent for Pb and Cd capturing. The results further showed that the capture ability depended on chemical compositions and specific surface area of the sorbents. Presence of HCl caused a little decrease in the capture ability, using aluminosilicate-based sorbents, while significant effect on the capture processes was noted when calcium-based sorbents were used. Furthermore, when kaolin was added into the sewage sludge, kaolin was an appropriate sorbent to control lead and cadmium emissions. Temperature increase enhances the capture ability under our experimental conditions. Kaolin addition played a role for low leachability of the trace metals. © 2003 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fuel.2003.10.022

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人日本エネルギー学会  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

Web of Science

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal De Physique. IV : JP  

Coal and wastes combustion have become an important issue not only in terms of energy generation but also environmental conservation. The need for alternative fuels and wastes management has made the two energy sources of importance. However, the utilization of the two is faced with problems of impurity trace metals in the fuel. These metals usually speciate during combustion or incineration leading to generation of fumes and subsequently particles. This paper reports on the study aimed at understanding the speciation of trace metals and their emission from combustion systems as particulates. Experiments carried out using a down-flow furnace and theoretical study carried out using lead, chromium and cadmium as basic metals had shown that their speciation and subsequent emission is controlled by both chemical composition and physical properties of the fuel. The physical and chemical and physical properties of the fuel and their respective compounds and the operating conditions of the incineration and combustion system control the enrichment of the particles with trace metals.

DOI： 10.1051/jp4:20030448

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Combustion Science and Technology  

Municipal waste combustion has been opted as a method for reducing the size of the volume, and consequently, for reducing the necessary requirement of areas for direct disposal. However, the emission of the conventional gaseous pollutants are not the only problem; traces of metal fumes emanate from the metallic compounds that are in the wastes. Efforts to control these metal fumes have not been so successful because of the complicated mechanisms of the metallic compounds during combustion. Failure of the conventional systems to trap the trace elements is due to their appearance with the submicron particles from the combustion and incineration systems. In this work, a thermomechanical equilibrium approach is employed to study the combustion and gasification behavior of trace metals with a case of lead, cadmium, and chromium during the incineration of sewage sludge. In this work, sulfur and chlorine have been found to play a key role in the speciation of the trace metals. However, these elements are only active when oxygen is present. A test on alkali metals mixed with trace metals showed that at low concentrations of S and Cl, the alkali metals react first with these elements before other metals. Chlorine assists in retaining most of the trace metals in the vapor phase while sulfur keeps them in the condensed form. The presence of iron, as is the case with most sorbents, hinders the reaction of Cl with the metals, thus suppressing the formation of volatile compounds.

DOI： 10.1080/713712965

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

Fundamental evolution characteristics of alkali metal compounds, especially sodium compounds in coal combustion/gasification were experimentally studied using a rapidly heated batch reactor under a wide range of temperature conditions. Six types of coal with different properties were reacted in the reactor. The evolution characteristics of sodium compounds obtained experimentally were compared with those predicted using both coal properties of cross-correlation coefficient between sodium and silicon in the raw coal and the fraction of condensed sodium aluminosilicates in the residue, calculated by the thermochemical equilibrium theory. The reason why the two indices were selected is that the sodium aluminosilicates was detected by X-ray diffraction analysis in the residue. The cross-correlation coefficient between sodium and silicon in the raw coal is calculated using two digital images of sodium and silicon distributions obtained by the Energy dispersed X-ray (EDX) analysis at the cross-section of raw coals. On the other hand, the chemical equilibrium calculation is performed by prescribing the experimental conditions and ultimate analysis data and ash compositions of the coal. The results predicted correlated well with the experimental data even when the evolution characteristics of sodium was dependent on the coal type and when the experimental conditions were varied widely. The coal with low cross-correlation coefficient between sodium and silicon and low fraction of condensed sodium aluminosilicates in the residue was found to release sodium compounds. Both of the two indices proposed can contribute to the prediction of fundamental evolution characteristics of alkali metal compounds in the coal combustion/gasification.

DOI： 10.1252/jcej.34.899

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOCIETY OF ENVIRONMENTAL SCIENCE, JAPAN  

DOI： 10.11353/sesj1988.14.333

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

Fundamental de-chlorination characteristics of Refuse-Derived Fuels (RDF), which were developed for use as a source of thermal energy, were studied by using both practical RDF and simulated RDF. For the simulated RDF polyvinyl chloride (PVC) or NaCl was added as a chlorine source. In the experiments, single pellets of RDF were burned in an electrically heated batch furnace. The de-chlorination efficiency was calculated by analysis of Cl in the residue after combustion. The efficiency obtained was compared with that obtained by chemical equilibrium calculation.<br>HCl was found to be mainly emitted during the volatile matter combustion. The de-chlorination characteristics for PVC addition differ from that for NaCl addition. For the RDF with PVC and Ca(OH)₂ addition, the de-chlorination reaction depends on the furnace temperature, and the optimum temperature is about 923 K. At low temperature the de-chlorination rate is slower than the evolution rate of HCl gas, whereas high temperature, CaCl₂, which is produced by the de-chlorination reaction, is decomposed during the char combustion. For the NaCl addition, C1 is not absorbed into a Ca compound. According to chemical equilibrium calculation, NaCl is evaporated as a form of NaCl and Na₂Cl₂ vapors, and HCl is not produced.

DOI： 10.1252/kakoronbunshu.27.604

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOCIETY OF ENVIRONMENTAL SCIENCE, JAPAN  

In order to realize a social system with sustainable development, it is necessary for local communities to construct inter-industries material circulation network. In this aspect, wastes evolving from the industries are defined as unused materials. This study suggests a methodology of constructing networks among different industries for reusable materials. Two types of databases are made by means of industrial surveys. One of the databases reveals information about raw material, products and wastes, which is received or emitted on each company of industries in a subject community. The second database defines conversion technologies that enable to transform the wastes into reusable materials. Based on the databases, a network simulator program can analyze material flows in the community. In this paper, Higashi-Mikawa area in Aichi Prefecture was chosen as a model of local community, and the databases of the industries and wastes treatment companies were made, furthermore the material flow for. selected wastes were simulated. Additionally, one suggestion about optimum material circulation network in an application of proper conversion technology is hypothetically designed.

DOI： 10.11353/sesj1988.14.231

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Iron and Steel Institute of Japan  

Reaction behaviors of a coke lump in raceway of blast furnaces which pulverized coal injection technology was adopted were studied by using a horizontal pulverized coal reactor. In the experiments two types of coke lump were used as samples. In the experiments, the reaction behaviors of coke lump were continuously observed by an 8 mm video camera system. Mass change of the coke lump was weighed at each exposure time, and surface temperature of the coke lump was also continuously measured by a two-color pyrometer. Additionally, both the reacting coal particles and gas were sampled and analyzed, and the deposition on the coke surface was also analyzed. In order to elucidate the effect of ash particles in coal on the coke reaction, LPG was also supplied as a fuel into the reactor instead of coal. <br>As a result, mass loss of coke in the coal combustion is larger than that in the LPG combustion. When the coal particles collide with the coke at the surface, the ash particles easily stick there and spherical molten ash is formed on the surface. For the LPG combustion, only small spherical molten ash resulted from the coke is formed. Those results suggest that ash particles of the coal may enhance coke degradation due to chemical interactions between coal ash and coke.

DOI： 10.2355/isijinternational.40.744

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

The adhesion behavior of ash generated during coal gasification under high temperature condition was investigated by using horizontal-type pulverized coal reactor with water-cooled tube. The size distribution and chemical composition of attacking and deposited particles on tube surface were measured by CCSEM (Computer Controlled Scanning Electron Microscopy). The fraction of fine size and low fusion temperature in collision particles selectively adhered to tube surface. The ash adhesion probability to dry surface was determined by the collision efficiency and viscosity prediction of each particle. Ash adhesion model that will be applied to the gasifier was proposed.

DOI： 10.20550/jiesekitanronbun.37.0_281

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

DOI： 10.20550/jietaikaiyoushi.9.0_285

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Influence of alkali metal compounds on desulfurization characteristics of sea-shell and limestone was elucidated quantitatively by using a thermobalance in this study. Scallop removed alkali metals and chlorine and Tsukumi limestone added several alkali metal compounds and chlorides were used as a sample. In order to elucidate additive effect of sodium chloride into the limestone on the desulfurization characteristics, the mean pore size by a pore sizer, the sulfur distribution within a reacting particle by an EDX system and the crystal structure of particles by a XRD system were measured.<BR>As a result, the desulfurization efficiency for the scallop even after removing the alkali metals and chlorine little changed. The addition of sodium chloride into the limestone can increase the desulfurization efficiency best. Both the mean pore size and the crystal structure of the calcined limestone, into which sodium chloride was added, was similar to those of the calcined scallop.Thus the desulfurization reaction produced over the whole of a particle. However, even if sodium chloride was added into the calcined limestone (CaO), the desulfurization efficiency was not promoted.

DOI： 10.3775/jie.79.1070

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Association of Aerosol Science and Technology  

In order to utilize low-grade coals, which contain high concentrations of sulfur (2-6 wt. %) and ash (>15 wt. %, dry basis), controlling pollutant emissions during combustion in domestic stoves and small-capacity industrial boilers, a composite solid fuel “coal-biomass briquette” with sulfur fixation function was produced in a pilot plant in Chongqing city, China. It was composed of 80 wt. % of low-grade coal and 20 wt. % of biomass (<I>e. g.</I>, wood chips and agricultural wastes) with a small fraction of sulfur-fixation additives. In this study, we investigated the ignition and combustion characteristics of the coal-biomass briquettes, and developed a new sulfur fixation additive made from sub-product in gas welding industries. It was found that the coal-biomass briquette has the lower ignition temperature and higher combustion efficiency than the usual coal briquettes, and that the newly developed additive was superior to limestone or scallop shells in sulfur fixation capability. This method is simple, economical, and efficient, in terms of emission control of SO<SUB>2</SUB>, CO and other particulate pollutants from the combustion of low-grade coals using the conventional domestic stoves and boilers without modification. The coal-biomass briquette can be applicable for pollution control of coal combustion in some developing countries.

DOI： 10.11203/jar.15.364

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/ef980127y

Web of Science

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

In combined cycle power generation systems for coal combustion and/or gasification, the vapor of alkali metal compounds may cause hot corrosion at the surface of blades of a gas turbine. The influence of coal type on fundamental evolution characteristics of alkali metal compounds, especially sodium compounds, in coal combustion is experimentally elucidated in this study by using a rapidly heated electrical batch combustor. Both classification of forms of sodium compounds and analysis of the cross-correlation coefficients between the existing locations of sodium and other elements in the cross-section of a particle of raw coal by using an EDX (Energy Dispersive X-ray) system and an image correlation method are conducted in order to quantify the effect of coal type on the sodium evolution characteristics.<BR>As a result, the evolution characteristics of sodium are influenced by the coal type. Most of the sodium evolved is classified as water-soluble sodium. Coal in which sodium chloride is contained as a major sodium compound evolves sodium compounds more easily than other coals do. The distributions of sodium, silicon and aluminum in a coal particle contribute to the evolution characteristics of sodium. Coals with high cross-correlation coefficients between sodium and silicon/aluminum show low evolution fraction of sodium.

DOI： 10.1252/kakoronbunshu.25.389

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

The characteristics of self-denitrification in biobriquettes are studied experimentally. To enhance effective utilization of low-grade coals, and to control emission of environmental pollutants from combustion, a new artificial solid fuel, a biobriquette with a self-denitrification function, is developed. It was produced by the mixture of low-grade coal, cornstalk as biomass and pulp black liquid as denitrificazer under a high compression pressure condition. Both experiments of pyrolysis and combustion were performed in order to reveal the mechanism of nitrogen-oxide formation and denitrification of the biobriquette.<BR>It is found that the release fraction of fuel-N is raised with increasing pyrolysis temperature in both coal and biomass. The release fraction of fuel-N in biomass is much higher than coal at the same pyrolysis temperature. The conversion fraction of fuel-N to NO slightly ascends and the fraction to N<SUB>2</SUB>O slowly descends with increasing furnace temperature, but the sum of conversion fraction of fuel-N to NO and N<SUB>2</SUB>O appears to be independent of furnace temperature. The denitrification process of the biobriquette with the pulp black liquid appears to proceed as two stages, namely the volatile combustion stage and the char combustion stage. Denitrification mainly happens in the char combustion stage. A denitrification efficiency of 40% can be obtained in the biobriquette combustion with a pulp black liquid of 10 mass%. Finally, it is confirmed for the first time that the pulp black liquid has significant denitrification capabilities in the biobriquette combustion.

DOI： 10.1252/kakoronbunshu.24.779

Scopus

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Symposium (International) on Combustion  

The characteristics of self-desulfurization and self-denitrification in biobriquettes were studied experimentally and numerically in this paper. The biobriquette was produced by mixing coal, biomass, desulfurizer, and/or denitrificater under a high-compression pressure condition. The combustion process of biobriquette appears in two stages, namely the volatile combustion stage and the char combustion stage. It was proved that limestone, wasted scallop shell, and calcium hydroxide have effective self-desulfurization capability in biobriquette combustion and that desulfurization mainly happens in the char combustion stage. Comparatively among the three desulfurizers used, calcium hydroxide has the highest desulfurization capability because of its lower calcination temperature, and scallop shell the second because of the larger porosity after calcination. A desulfurization efficiency as high as about 80% can be reached for some kinds of coals using scallop shell as desulfurizer with Ca/S over 3. A modified shrinking-core model was developed to predict the desulfurization efficiency in the char combustion stage, and an approximate agreement was obtained between the predictions and the experiments. It was also found that pulp black liquid, an industrial waste to roll as binder in the biobriquetting process, has both self-denitrification and self-desulfurization capabilities in biobriquette combustion. A denitrification efficiency of about 40% can be obtained by adding the pulp black liquid into biobriquette with about 15% in mass.

DOI： 10.1016/S0082-0784(98)80157-4

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JSAE Review  

In order to reduce the pollutants from diesel exhaust, high-pressure gas was injected during combustion into a modified pre-chamber of an IDI diesel engine at a varied load and gas injection timing. The result shows that high-pressure gas injection can reduce the particulates and NOx simultaneously, with little influence on the engine performance. The combustion process in the pre-chamber was visualized by means of an ultra high-speed video system and image analysis of the pictures obtained. The results of the visualization show that by injecting gas, the flame is first quenched, followed by the reduction of NOx in the pre-chamber by hydrocarbon. Although high-pressure gas injection could have caused a substantial increase in HC as a result of temperature quenching, this seems to be controlled by the consumed portion of HC during the recycling of NOx. Chemical analysis of polycyclic aromatics compounds was carried out for the purpose of establishing its variations with gas injection. It was established that gas injection not only reduces PM by oxidation of solid carbon, but also the PAH component. © 1997 Society of Automotive Engineers of Japan, Inc. and Elsevier Science B.V.

DOI： 10.1016/S0389-4304(97)00013-1

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering  

A modified pre-chamber of an indirect injection (IDI) diesel engine was used to elucidate the influence on emissions of compressed air injection into the pre-chamber during combustion. The test parameters were air injection timing and arrangements of gas injection. This paper presents the experimental results for two types of injection arrangements; I- and Y-type. The I-type is arranged such that the gas injection jet and fuel injection nozzle are in opposite directions, while the Y-type is such that it forms a 'Y' shape with the nozzle and the passageway. Results obtained reveal that the Y-type arrangement is superior in combustion characteristics and emissions reduction to the I-type. A remarkable reduction in both particulate matter (PM) and NOx is realized at air injection timings during 35° and 65° after top dead centre (ATDC). The reduction mechanism can be explained as due to the induced turbulence which improves mixing and heat transfer. The effect of the modifications on the performance of the engine was evaluated based on the fuel economy and efficiency. This evaluation has shown that the test cylinder approximates closely to the normal cylinder of the original engine. © IMechE 1997.

DOI： 10.1243/0954407971526380

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 日本機械学会  

DOI： 10.1299/jsmemag.100.947_1108

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

Characteristics of pyrolysis and combustion of biobriquettes were studied by using an electrically heated batch combustor. The influences of biomass content of the biobriquette on the combustion characteristics which were obtained by measuring the fuel consumption profile and the experimental results were analyzed by both volume and shrinking-core reaction models.<BR>The following conclusions were obtained (1) total volatile matter content in the biobriquette was directly proportional to its biomass content. Biomass in the biobriquette promotes ignitability and burning rate of low grade coal ; (2) combustion time history was divided into two stages, in which volatile matter mainly evolved and burned to lead fixed carbon combustion ; (3) in the former stage, the reaction rate constant and its order always remained linear related to biomass content ; (4) in the latter stage, the combustion behavior may be simulated by using the shrinking-core reaction model and the reaction was controlled by oxygen diffusion through both the gas boundary layer film and the ash layer almost evenly, and ash layer diffusion coefficients were also linear related to biomass content.

DOI： 10.1252/kakoronbunshu.23.404

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CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

In order to obtain fundamental data for alkali metal vaporization, the evaporation rate of alkali chlorides and alkali sulfates (NaCl, KCl, Na<SUB>2</SUB>SO<SUB>4</SUB>, K<SUB>2</SUB>SO<SUB>4</SUB>), which are major alkali compounds present in coal, were measured under inert, oxidizing and reducing atmosphere by using a thermobalance. A diffusion model was applied to obtain alkali metal evaporation data and identify an evaporating path and a rate controlling phenomena.<BR>Alkali chlorides evaporated as monomers and dimers. The evaporation rate is explained by a diffusion model. In the case of alkali sulfates, a dissociation reaction occurred simultaneously with evaporation as monomer. In inert and oxidizing atmospheres, the dissociation reaction was represented as<BR>M<SUB>2</SUB>SO<SUB>4</SUB>⇒2M+SO<SUB>2</SUB>+O<SUB>2</SUB><BR>Evaporation rates can be calculated by a diffusion model in oxidizing atmosphere. In an inert atmosphere, however, when dissociation becames remarkable evaporation rate is controlled by the dissociation rate. Under a reducing atmosphere the expected reaction was represented as<BR>M<SUB>2</SUB>SO<SUB>4</SUB>+2CO⇒2M+SO<SUB>2</SUB>+2CO<SUB>2</SUB><BR>This reaction does not reach equilibrium, so that the following reactions controll evaporation rate.<BR>M<SUB>2</SUB>SO<SUB>4</SUB>⇒2M+COS+5CO<SUB>2</SUB><BR>COS+2CO<SUB>2</SUB>⇒SO<SUB>2</SUB>+3CO

DOI： 10.1252/kakoronbunshu.23.635

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CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

The combustion time history of a biobriquette is divided into two stages in which volatile matter content mainly evolves and burns prior to char combustion. The volume model for the former stage and the shrinking-core reaction model for the latter stage are employed to calculate the combustion rate of the biobriquette. In this study, the influence of briquette shape, compression pressure and types of coal on the combustion rate are investigated by using the two models and experimental data.<BR>The shapes of spherical and cylindrical biobriquettes hardly influence the combustion behavior of the biobriquette (if they have same diameter and the length of cylinder is equal to its diameter). Compression pressure has no effect on the rate of the former stage but gave obvious effect on the latter stage through the density change of the biobriquette when it is under about 245 MPa. The reaction rate constant and its order vary linearly with the fuel ratio of coal briquette in the former stage. The type of coal and compression pressure have a larger influence on the rate of the latter stage due to different porosity in the ash layer. Finally, the combustion rate can be analyzed by the obtained models and semi-empirical equation.

DOI： 10.1252/kakoronbunshu.23.954

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：一般社団法人日本機械学会  

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

DOI： 10.20550/jietaikaiyoushi.4.0_103

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

Desulfurization characteristics of shells (scallop (Hotate), short-necked clam (Asari) and oyster (Kaki)) were studied by using a thermobalance and compared to the results obtained by limestones (Tsukumi-and Funao-Brand) currently used as desulfurizers. First, such physical and chemical properties of these samples as specific surface area, pore size distribution and chemical constituents are identified. In the thermobalance experiments the calcination temperature, the rate of temperature increase to this point, and the desulfurizing temperature are changed, and the particle diameter is fixed in the range of 297-420 μm. After calcination is carried out in N<SUB>2</SUB> gas, the sample is sulfurized in SO<SUB>2</SUB>+O<SUB>2</SUB> gas in N<SUB>2</SUB> balance. The cross-sectional sulfur distribution within the reacted particle is measured by a two-dimensional XMA. Results show there is no correlation between the desulfurization efficiency and the specific surface area. However the desulfurization efficiency depends on the pore size distribution. The desulfurization efficiency of shells becomes higher than that of limestones. In the case of limestone, sulfur is only trapped near the particle surface since the micro-pores are plugged due to CaSO<SUB>4</SUB>. In the case of the shells, however, the sulfur is distributed over the whole body.

DOI： 10.1252/kakoronbunshu.21.904

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

Formation/destruction characteristics of nitrous oxide (N<SUB>2</SUB>O) in bubbling fluidized-bed coal combustion, especially in char combustion, were experimentally studied, using a fixed-bed reactor in which char particles were packed in a single layer. In the combustion experiment, such combustion parameters as bed temperature, supplied oxygen concentration and char type were varied. The change of gas species concentration and compositions in the burning char were analyzed during the char combustion process.<BR>In the initial stage of char combustion, NO was produced rapidly, but N<SUB>2</SUB>O concentration increased slowly. This result is caused by N<SUB>2</SUB>O destruction due to H radical, which is produced from the oxidation of CO. In the latter half of combustion, however, N<SUB>2</SUB>O concentration increased faster since the formation rate of H radical decreased. The N<SUB>2</SUB>O concentration increased with decreasing bed temperature and with increasing supplied O<SUB>2</SUB> concentration. This tendency is similar to that in the volatile combustion. From chemical and physical analyses of the burning char particles, the evolution behavior of N-component is influenced by the difference in surface and internal structures (network or balloon type) during the char combustion.

DOI： 10.1252/kakoronbunshu.20.482

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

One of the main sources of N<SUB>2</SUB>O production is considered to be exhaust gas released from low temperature coal combustors. In this study N<SUB>2</SUB>O formation/destruction characteristics in pulverized coal combustion under low temperature condition are discussed by changing coal types. The experimental apparatus is a one dimensional electrically heated laminar flow reactor. By calculating the mass balance of nitrogen included in both the sampled burning particles and combustion gas, the effect of gas species including nitrogen (HCN and NH<SUB>3</SUB>) on N<SUB>2</SUB>O formation is studied experimentally.<BR>N<SUB>2</SUB>O is mainly produced during volatile matter combustion. Coals which emit more HCN than NH<SUB>3</SUB> produce higher N<SUB>2</SUB>O concentration. After volatile matter combustion, N<SUB>2</SUB>O concentration increases again and NO concentration decreases gradually. This result can be explained by means of the mass balance of nitrogen. An increase in N<SUB>2</SUB>O in char combustion may be caused not only by the reaction between NO and carbon in char : NO + (char-C) -NCO and NCO + NO→N<SUB>2</SUB>O +CO, but also the reaction between nitrogen in char and NO : (char-N) +NO→N<SUB>2</SUB>O. The conversion from fuel nitrogen to N<SUB>2</SUB>O increases with a decrease in the burning fraction and with a decrease in the fuel ratio. This tendency depends on the difference of temperature and combustion atmosphere surrounding coal particles.

DOI： 10.1252/kakoronbunshu.20.843

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

Characteristics and mechanisms of N<SUB>2</SUB>O formation/destruction in bubbling fluidized-bed coal combustion were studied experimentally and theoretically. Combustion experiments were carried out to find the influence of bed temperature, combustion stoichiometry, coal type and feeding method of coal particles on N<SUB>2</SUB>O formation. To obtain get a deeper understanding of the mechanisms of N<SUB>2</SUB>O formation/destruction, the homogeneous volatile combustion in the freeboard were simulated numerically. The effect of bed temperature, combustion stoichiometry and volatile-N species on N<SUB>2</SUB>O formation and the controlling reactions of N<SUB>2</SUB>O formation/destruction are analyzed.<BR>This study finds that N<SUB>2</SUB>O concentration increases with decreasing bed temperature and with increasing combustion stoichiometry. On the other hand, NO concentration changes little against bed temperature, but increases with increasing combustion stoichiometry. N<SUB>2</SUB>O seems to be mainly formed from the volatile matter combustion. HCN and NH<SUB>3</SUB>, evolved as volatile-N species, strongly contribute to form N<SUB>2</SUB>O as well as NO. Especially, HCN contributes more to forming N<SUB>2</SUB>O than does NH<SUB>3</SUB>. On the other hand, H radicals produced by the oxidation reactions of CO and H<SUB>2</SUB> promote the destruction of N<SUB>2</SUB>O.

DOI： 10.1252/kakoronbunshu.20.178

Scopus

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

DOI： 10.3775/jie.72.252

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

The combustibility of finely powdered fly ash A and B, discharged from a combustion furnace operated at 1673 K and a fluidized-bed combustor at 1123 K, respectively, was investigated by applying nonisothermal reaction analysis with a thermo-gravimeter. The combustion experiments were carried out in an atmosphere of air flow under the following conditions : sample size < 37μm, heating rate 1-1000 K/min, and temperature up to 1173K. The results obtained are as follows.<BR>1) When heating rate is below 2 K/min the combustion becomes reaction-controlled; when it is above 700 K/min the combustion becomes diffusion-controlled.<BR>2) The combustion reaction parameters and effective diffusivity of oxygen in ash were fly ash A : <I>E</I> 70.1 (kJ/mol), <I>A</I>=0.71 (Us kPa), <I>D</I><I><SUB>c</SUB></I> =1.66× 10<SUP>-5</SUP> (cm<SUP>2</SUP>/s) <BR>fly ash B : <I>E</I> = 82.0 (kJ / mol), <I>A</I>=13.3 (1/s kPa), <I>D</I><I><SUB>c</SUB></I>= 1.94×10<SUP>-5</SUP> (cm<SUP>2</SUP>/s) <BR>3) The combustibility of fly ash A is sampller than that of char A. It was observed that part of the unburned carbon in fly ash A was converted to graphite.<BR>4) The combustibility of fly ash B is slightly greater than that of char B. This difference was considered to be caused by the difference in specific surface area of unburned carbon between char B and fly ash B.

DOI： 10.1252/kakoronbunshu.19.48

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Symposium (International) on Combustion  

Characteristics of N2O formation/destruction in coal combustion are studied experimentally and theoretically over a wide range of combustion temperature. The combustion experiments are carried out in pulverized (1200-1700 K) and bubbling fluidized bed (1000-1200 K) coal combustors to find the influence of combustion temperature, combustion air ratio and coal type on N2O formation. The effect of catalytic reactions by char, CaO and stainless steel particles on the N2O destruction reaction are also tested by using a packed bed reactor. In order to get a deeper understanding of the mechanisms of N2O formation/destruction, numerical simulations are carried out for homogeneous volatile combustion and for combustion of single coal particles. The controlling reactions of N2O formation/destruction are analyzed. The experimental and numerical study found that N2O was mainly formed from the volatiles combustion. The low temperature and oxidizing atmosphere favor N2O formation. N2O concentration increases with decreasing temperature and with increasing air ratio. HCN and NH3, evolved as volatile-N species, make important contributions to the formation of N2O as well as NO. Especially, HCN contributes more to the formation of N2O than NH3 in the low temperature range. On the other hand, H radicals produced by the oxidation reactions of CO and H2 promote the destruction of N2O. Char, CaO and stainless steel particles also act as N2O destruction catalysts. © 1992 Combustion Institute.

DOI： 10.1016/S0082-0784(06)80165-7

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

The local and the average heat transfer coefficients between gas and solid particles in a circulating fluidized bed were estimated by temperature profiles by use of the heat balance equation. Characteristics of interfacial heat transfer were studied on an experimental basis.<BR>The local heat transfer coefficient showed high value near the bottom of the riser. Above this elevation the local heat transfer coefficient gradually decreased to a constant value. The coefficient is influenced by a change in slip velocity between gas and solid particles. The average heat transfer coefficient was well correlated with the particle Reynolds number with slip velocity. The Nusselt number obtained in the circulating fluidized bed condition was low comparing with that in the pneumatic conveying and bubbling fluidized bed conditions. The Nusselt number decreased with an increase in total particle hold -up in the riser. These results suggest that heat transfer between gas and solid particles in the circulating fluidized bed condition depends on the solid particle behavior and gas flow characteristics.

DOI： 10.1252/kakoronbunshu.18.600

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

An optical method to measure particle and gas temperatures simultaneously and separately was proposed in order to study a combustion mechanism in pulverized coal combustion fields. The particle temperature was measured by high-speed two-color thermometry. The gas temperature was measured by an Na-D line reversal method. The CT method was used to (computed tomography) estimate the cross-sectional tem-perature distributions along the pulverized coal combustion field. Attenuation of radiation by the particles along the optical path was taken into account in the temperature calculation. The applicability of this method was demonstrated by computer simulations for artificial temperature and particle concentration distributions.<BR>The temperature distribution in the furnace was correctly obtained by the experimental projection data by means of the CT method. The experimentally obtained particle and gas temperature distributions showed that there existed a great difference between these two temperatures. In the volatile combustion region the particle temperature was higher than the gas temperature, and the fluctuation of particle temperature was also larger than that of gas temperature. In the char combustion region, on the other hand, the gas temperature became higher than the particle temperature.

DOI： 10.1252/kakoronbunshu.18.643

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

To detect oil leakage in a dynamo or transformer, a direct and simple method is proposed in this study. The oil leakage detector was manufactured and tested as a labo -scale experiment. Sample insulation, lubrication and control oils were used. Based on the results obtained, the detector was applied to a practical dynamo and transformer. To study the coloring mechanism of the detector, important chemical species included in those oils were identified by using an FID gas chromatograph, a GC mass -spectral analyzer and a nuclear magnetic resonance analyzer.<BR>Labo -scale experiments showed that a detector combining a coloring matter with a developed color was usable for leakage detection of the three kinds of oil used. Water did not interrupt the oil leakage signal detected. From measurements of detail chemical properties the key coloring component was an aromatic proton. Before doing practical tests such the safety of the detector as the electric resistance, the destructive voltage of insulation and the temperature characteristics was confirmed in advance. The detector was able to defect oil leakage in practical use.

DOI： 10.1252/kakoronbunshu.18.562

CiNii Research

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

A CFM-bed (Combined Fast Fluidized Bed and Moving Bed) gas-solid contactor was applied to a solid fuel combustor. This combustor was proposed as a promising solid-fuel combustor with high efficiency and a countermeasure against environmental pollution. The combustor is composed of a set of double pipes. A fast fluidized bed and/or an entrained bed is formed in the inner pipe where partial combustion of coal particles may take place. A moving bed is made at the outlet of the annular part wherechar combustion may happen.<BR>In the present study, Loy Yang coal and coke were used as a typical low-grade solid fuel. Rich and lean combustion limits were experimentally investigated with a single-staged combustion mode by changing the primary air ratio. It was confirmed that this combustor could be operated successfully in a wide operational range of primary air ratio from 0.3 to 2.4. The principal ignition mechanism of the fule in this combustor was made clear by considering not only internal particle circulation but also the exhaust heat recirculation from the annular part to the inner pipe.

DOI： 10.1252/kakoronbunshu.15.105

CiNii Research

Publishing type：Research paper (scientific journal)  

DOI： 10.2355/isijintemational.ISIJINT-2019-692

Web of Science

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Currently, pulverized coal is blown into blast furnaces to reduce the amount of coke used in the steelmaking process. On the other hand, in recent years, the grade of coal has been declining due to the increase in the use of coal, and the company has been forced to respond to the diversification of coal types. Therefore, in this study, we used a batch furnace to prepare three types of coal char, and then the cross-sectional observation of the char by SEM and specific surface area analysis by BET method using N₂ were carried out. Coal with porous particles and high specific surface area values was found to have very high gasification reactivity for both CO₂ and H₂, while coal with balloon-type particles with large cavities inside the particles and low specific surface area values was found to have lower gasification reactivity.</p>

DOI： 10.20550/jiesekitanronbun.57.0_2

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In this study, effects of tar-containing fuel gas on the SOFC with Ni-YSZ as anode electrode are evaluated. The simulated gas was hydrogen contaminated with toluene as model substance of tar. Electrochemical behaviors were investigated under several toluene concentrations in wet (2.3vol% H₂O) H₂ at 850°C during 30h using constant current measurement and impedance analysis in order to assess the SOFC's stability. Constant current measurements were conducted under 200mA/cm² mainly and impedance analysis was conducted under OCV conditions. Experimental results show that the presence of tar dramatically reduces the electrochemical performance of SOFC even under a low concentration of 100ppm. It was also indicated this reduction tend to be serious when concentration of toluene increase.</p>

DOI： 10.20550/jietaikaiyoushi.29.0_130

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Oxy-Fuel combustion is one of the techniques to achieve carbon dioxide capture and storage (CCS). Meanwhile, fluidized bed combustion has the advantage of increasing combustion efficiency due to particle flow. Oxy-fuel coal combustion in a fluidized bed is a relatively new study, so the combustion behavior remains unclear. In this study, we investigated Oxy-fuel coal combustion behavior by comparing three combustion atmospheres, air, CO₂-O₂ and Oxy-Fuel using bubbling fluidized bed reactor. Especially in this research, we focused on the production of SOx, and in Oxy-fuel combustion, the concentration of SO₂ increased due to the effect of recirculation. Regarding SO₃ generation in Oxy-fuel combustion, the concentration became high due to the influence of SO₂ circulation and H₂O circulation.</p>

DOI： 10.20550/jiesekitanronbun.57.0_4

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.talanta.2019.05.115

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PubMed

Publishing type：Research paper (scientific journal)   Publisher：Journal of Material Cycles and Waste Management  

DOI： 10.1007/s10163-019-00883-9

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Publishing type：Research paper (scientific journal)   Publisher：Energy and Fuels  

DOI： 10.1021/acs.energyfuels.9b00672

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jhazmat.2019.05.045

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PubMed

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.energyfuels.8b04341

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.fuel.2018.10.084

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.proci.2018.06.175

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers and The Heat Transfer Society of Japan  

<p>The effective utilization of sub-bituminous coals should be extended as an energy source for power generation because of their low cost and long minable years. However, sub-bituminous coal may undergo spontaneous combustion owing to high reactivity with oxygen in low-temperature air compared with bituminous coal. Therefore, the objective of this study is to elucidate the low-temperature oxidation behaviors of sub-bituminous coal. In particular, transition from oxygen chemisorption to low-temperature oxidation of sub-bituminous coal has been experimentally examined in detail. Isothermal gravimetric analyses are conducted for several bituminous and sub-bituminous coal samples at temperatures varying between 356 K and 476 K in oxygen-enriched air. The chemical compositions of emission gas are continuously monitored under low-temperature oxidation conditions. The changes in the chemical structure of the coals are analyzed using Fourier transform infrared (FTIR) spectrometry. The experimental results show that the mass of all tested coals, including those of bituminous and sub-bituminous coals, increases at temperatures below 426 K as a result of oxygen chemisorption. At 476 K, the mass of sub-bituminous coal increases slightly with low H₂ and CO₂ emissions at the beginning and subsequently decreases with high CO and CO₂ emissions. This mass change indicates that the transition from oxygen chemisorption to low-temperature oxidation occurs during this period. In addition, the FTIR spectra of sub-bituminous coals show the existence of carbonyl groups even in raw coal samples. These carbonyl groups are considered to contribute to the formation of CO₂ and H₂ from the beginning of reactions, triggering the transition from oxygen chemisorption to low-temperature oxidation.</p>

DOI： 10.1299/jtst.2019jtst0005

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CiNii Research

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Currently, the proportion of fossil fuel in the primary energy supply in Japan is very high. So, the use of renewable energy is collecting a lot of attention as an alternative to fossil fuel. Biomass, a type of renewable energy, has the advantage of carbon neutral. On the other hand, Biomass has the disadvantage of low power generation efficiency when using power generation because of the low energy density. From these backgrounds, biomass co-combustion for coal fired power generation has been focused on. In this study, co-combustion experiments of pulverized coal and biomass samples were carried out, in order to investigate the effect of mixture ratios and types of biomass samples on co-combustion behaviors.</p>

DOI： 10.20550/jiesekitanronbun.56.0_28

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In coal-fired power generation, De NOx catalysts are known to deteriorate over time, but its mechanism has not been clarified yet. According to the previous research, it has been found that amorphous silica forms a thin layer on the catalyst surface, which composition are much different from those of coal ash. It implies that coal ash itself does not adhere on the surface of the catalyst, but Si compounds in the gas deposits to the catalyst. In order to confirm this consideration, deposition behaviors of vapor Si compounds to the catalyst surface were examined, and its effect on the catalyst performance was investig ated. High volatile siloxane was selected to simulate vapor Si compounds in exhaust gas. Two kinds of experiments are conducted, such as exposure and immersion tests. In the former, test pieces of the catalyst were exposed to siloxane vapor. In the latter, test pieces were immersed in liquid siloxane and calcined afterward. The amount of silica deposition on the surface of the catalyst was analyzed by SEM / EDX. In the catalyst performance evaluation test, dete rioration of the catalyst by silica adhesion wa s confirmed.</p>

DOI： 10.20550/jiesekitanronbun.56.0_10

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Coal combustion process discharges a large amount of ash, compared with petroleum and natural gas combustions. Coal ash particles melt and partially volatilizes at high temperature zones, causing many problems. In this study, ash deposition experiment was carried out, using simulated heat transfer tubes made of thermal spraying material. Coal ash was injected into the furnace via high penetrance at a high temperature. The molten slag formation ratio of their chemical composition in a single coal was estimated by the thermodynamic equilibrium calculation and the change of ash deposition characteristics was quantitatively discussed.</p>

DOI： 10.20550/jietaikaiyoushi.28.0_8

Publishing type：Research paper (scientific journal)   Publisher：12th Asia-Pacific Conference on Combustion, ASPACC 2019  

Scopus

Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the Combustion Institute  

DOI： 10.1016/j.proci.2018.07.064

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

Molten salt gasification is a promising way for collaborative use of solar energy and Zhundong coal, with in situ capture of Cl/S-pollutants as well as alkali metals. The present study provides a deep insight into carbon conversion during molten salt gasification of a typical Zhundong coal in ternary carbonate eutectics (Li2CO3-Na2CO3-K2CO3). The results demonstrated that the molten salt gasification of Zhundong coal underwent a rapid devolatilization of raw coal and then the gasification of char. The interactions between CO2 and volatiles promoted the cracking of macromolecular compounds, increasing the carbon conversion efficiency during the devolatilization process. The gasification of char was mainly determined by the direct reaction with molten salt, which was slightly affected by the CO2 concentration in the carrier gas. The results of char characterization evidenced that the condensation/graphitization of char was stimulated in the molten eutectics. Meanwhile, a large amount of O-containing groups, especially carbonyl groups, were formed in the molten salt treated char with carbonates as oxygen supplier. Under the influence of molten salts, some carbonyl groups would be formed inside the char. However, the decomposition of those carbonyl groups was suppressed by the mass transfer resistance of the released CO and/or CO2. Applying proper feeding mode, such as feeding coal in pulverized form, could enhance the contact of coal, molten salt and CO2, which remarkably promoted the interactions between molten salts and char containing functional groups.

DOI： 10.1016/j.fuel.2017.12.051

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

This study describes an ionization source for mass analysis, consisting of glow discharge plasma driven by a pulsed direct-current voltage for soft plasma ionization, to detect toxic volatile organic compounds (VOCs) rapidly and easily. The novelty of this work is that a molecular adduct ion, in which the parent molecule attaches with an NO+ radical, [M + NO]+, can be dominantly detected as a base peak with little or no fragmentation of them in an ambient air plasma at a pressure of several kPa. Use of ambient air as the discharge plasma gas is suitable for practical applications. The higher pressure in an ambient air discharge provided a stable glow discharge plasma, contributing to the soft ionization of organic molecules. Typical mass spectra of VOCs toluene, benzene, o-xylene, chlorobenzene and n-hexane were observed as [M + NO]+ adduct ion whose peaks were detected at m/z 122, 108, 136, 142 and 116, respectively. The NO generation was also confirmed by emission bands of NO γ-system. The ionization reactions were suggested, such that NO+ radical formed in an ambient air discharge could attach with the analyte molecule.

DOI： 10.1016/j.sab.2017.11.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Tokyo  

For thermal recycle by wasted plastics coated around electric cables, ignition and combustion experiments of the pulverized samples were carried out, using two types of electrically heated drop tube furnace, in which the particles are pulsatively fed and continuously fed, respectively. The ignition phenomenon was defined as occurrence of luminous emission from a cloud of the particles fed in the former furnace. The wasted plastics coated around the electric cables mainly make of polyethylene with a little amount of carbon particles. The ignition characteristics of the pulverized plastic samples as well as graphite particles as a reference sample were studied, changing the particle diameters and the furnace wall temperatures. In the electrically heated drop tube furnace with the continuous feeding system, the wall temperature and stoichiometric combustion air ratio were varied to elucidate the fundamental combustion characteristics. As a result, the ignition temperature depended on the particle diameter. The plastics with the particle diameter ranged from 150 to 300 µm could ignite at the lowest furnace temperature. From the continuous combustion tests, CO and lower molecule hydrocarbons like CH4, C2H2 and C2H4 were produced in the upper region of furnace. Finally, all of them gradually burned out.

DOI： 10.1007/s10163-017-0618-0

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Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 廃棄物資源循環学会  

Four kinds of fly ash from three municipal solid incinerators in southern China were examined in this study. The characteristics of fly ash were examined and acid leaching treatment was used to remove heavy metals from samples. The toxicity characteristic leaching procedure (TCLP) was executed to assess the effect of acid leaching method to fly ash samples. The experiment results showed that the contents of Cd and Pb in the original fly ash were higher, which classified them into the hazardous waste list. With the treatment of water washing and acid leaching, all fly ash samples removed heavy metals efficiently and the contents of heavy metals in treated fly ash met the admittance criterion of sanitary landfill.

DOI： 10.14912/jsmcwm.29.0_603

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>One of the important purposes of the coke in the blast furnace is the spacer to ensure the gas and liquid permeability. In other hands, ash particles in coke became slags inside the furnace and these are one of the causes that significantly worsen the permeability. In this study, combustion and gasification experiments of coke were conducted at each experimental temperature. Ash particles in the coke samples were analyzed by using SEM in order to clarify effect of temperatures on ash particles characteristics during combustion and gasification of coke.</p>

DOI： 10.20550/jiesekitanronbun.55.0_36

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Zhundong coalfield in China is the largest intact coalfield in the world. However, serious fouling and slagging issues occurred when the Zhundong coal combustion, because of its high Na and Ca contents. In this study, a novel CO2-water leaching method was proposed to remove Na and Ca in Zhundong coal. The removal efficiencies of Na and Ca and the ash characteristics of the leached coal were investigated in detail. The results show that the CO2-water leaching can be easily achieved at room temperature under atmospheric pressure. The removal efficiencies of Na and Ca by the CO2-water leaching were significantly higher than those of water leaching. It is attributed to the effective removal of the organic Na and Ca in the coal. In addition, the CaCO3 in the coal was also effectively removed by CO2-water leaching. The volatility of Na from CO2-water leached coal is only 25% of that of raw coal during the combustion at 900 degrees C. The alkali-acid ratio (B/A) of the CO2-water leached coal ash was significantly lower than those of the raw coal and the water leached coal ashes. The fusion temperature of the CO2-water leached coal ash significantly increased, compared with those of the raw coal and the water leached coal ashes. The deformation temperature of the CO2-water leached coal ash was as high as 1202 degrees C, much higher than those of the raw coal and water leached coal ashes, which were 1098 degrees C and 1142 degrees C, respectively. Besides, the agglomeration and sintering phenomena of coal ash was also inhibited significantly by the CO2-water leaching. Therefore, the CO2-water leaching method was found to be an effective and promising method for AAEM removal from Zhundong coal, and can markedly mitigate the fouling and slagging during Zhundong coal combustion.

DOI： 10.1016/j.fuel.2017.08.046

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Molten salt gasification provides a promising way for the combined usage of solar energy and coal, during which molten salts act as a heat storage and transfer medium. However, the interactions between coal ash components and molten salts might have undesired effects on the molten salt gasification. The present study investigated the distribution of mineral matters in typical Zhundong coals and the fate of coal ashes in the high-temperature Li2CO3-Na2CO3-K2CO3 eutectic system. The results showed that alkali and alkaline earth metals (AAEMs) were widely distributed in Zhundong coals in the forms of NaCl, CaCO3, CaSO4 and organic matter, which were predominantly dissolved in the molten salts. After the dissolution of these AAEMs, the melting temperature and enthalpy of the molten salts were changed, while the viscosity of the mixtures was hardly affected in melting phase. On the other hand, Si/Al-compounds were also of high content in some Zhundong coals, existing as quartz, kaolin and amorphous species. Some of these compounds tended to react with molten salts, by forming Li-silicate or Li/K-aluminosilicates, which were precipitated out of the system. Meanwhile, the suspension of the unreacted Si/Al-compounds increased the viscosity of molten salts. Additionally, interactions between coal ashes and molten salts brought about the decrease in thermal diffusivity and thermal conductivity of the eutectic system as well as the increase in specific heat capacity. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fuel.2017.06.079

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

A promising approach to decrease CO2 emissions from blast furnaces during ironmaking is to blow a reducing gas containing hydrogen into blast furnaces from their tuyeres. However, the combustion behavior of pulverized coal in the presence of a hydrogen-containing gas has not been elucidated. In this work, the combustion experiments of pulverized coal using a drop tube fumace were carried out to investigate the effect of H-2 gas addition on the combustibility of pulverized coal. The combustion ratio of char particles in the presence of H-2 gas (when introduced at a flow rate of 0.10 L/min) was larger than that in the absence of H-2 gas. This is because of the enhanced release of volatile matter from coal and the combustion of char due to an increase in the temperature of the coal particles, which was caused by the drastic combustion of H-2 gas. The combustion ratio of char particles when H-2 gas was added at flow rates higher than 0.21 L/min was considerably smaller than that obtained when H-2 gas was not added. It was found that the combustibility of coal was enhanced when an optimum H-2 gas flow rate was used. (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fuproc.2017.02.034

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

In order to predict ash deposition in a pulverized coal combustion process, the fragmentation, detachment, and coalescence behavior of ash particles in coal were quantitatively evaluated to distinguish between excluded and included minerals. The experiments for simulated EM heating and simulated coal combustion were carried out in a drop tube furnace. Change in the numbers of EM and IM particles were measured at different residence times by scanning a sampling probe along the flow direction in the reactor tube. The rate constants of EM fragmentation were estimated from the simulated EM heating experiment. The solution to a system of differential equations that includes the effects of fragmentation, detachment, and coalescence as functions for the numbers of EM and IM was obtained as a kinetic model. These functions were fitted to the experimental results for simulated coal combustion experiment to obtain the rate constants for detachment and coalescence. This method was also applied to previous experimental results using three actual coal samples. The rate constants of detachment and coalescence were mainly affected by char structure during coal combustion. (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fuproc.2017.02.033

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：ARPN Journal of Engineering and Applied Sciences  

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

In this study we performed a non-isothermal thermogravimetric analysis on three thermoplastics-ABS, PC and PE. The Coats and Redfern method (Nature 201: 68-69, 1964) was then used to approximate the kinetic parameters of each material. In addition, we performed a series of pyrolysis experiments in a batch reactor, for each plastic. The experiments were performed over the temperature range of 600-1000 degrees C at a constant residence time. The liquid and solid products of the pyrolysis, were collected, separated and weighted. Those products were categorized as soot, tar and char (PC only), and their relative weight to initial sample weight (DAF) was plotted against the temperature. The tar measured was exclusively medium to high molecular weight (&gt;80 g/mol). Results revealed that relative tar and soot production, for all three materials, first increases and then decreases with temperature increase. The maximum achieved tar yields for ABS, PC and PE were at 700, 650 and 800 degrees C, respectively; and the maximum soot yields were at 1000, 1000, 950 degrees C, respectively.

DOI： 10.1007/s10163-016-0470-7

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>Consumption of subbituminous coal will be expanded due to its low cost and long minable years around the world. However, a control of spontaneous firing at the stock yard is one of outstanding issues for the utilization of subbituminous coal. Therefore, an objective of this study is the elucidation of low-temperature oxidation behaviors of subbituminous coals. Several subbituminous and bituminous coals were selected as experimental samples for low-temperature oxidation. Mass changes of coal samples were measured by thermos-balance at the temperature between 356K and 476K in 50%N₂-50%O₂ atmosphere. Differences of molecular structures of coals between before and after low-temperature oxidation were analyzed by FTIR As a result, the aliphatic carbon in the coal was confirmed to react with oxygen, forming carbonyl group.</p>

DOI： 10.20550/jietaikaiyoushi.26.0_24

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>To elucidate fundamental combustion behaviors of some solid combustible wastes under isothermal conditions, the isothermal combustion experiments are carried out, using an electrically heated vertical batch furnace. The effects of the furnace temperature and the oxygen partial pressure in the reaction atmosphere on the combustion behaviors are studied experimentally and kinetically. As a result, the completion period of the overall combustion decreases with increases of both the furnace temperature and the oxygen partial pressure.</p>

DOI： 10.20550/jietaikaiyoushi.26.0_186

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

<p>In this study, we conducted coal gasification experiments by electrical drop tube furnace. In the experiments, we used Low Pressure Impactor (LPI) for the particle sampling in different particle size. Captured particles are dissolved in the acid on each particle size and the trace element concentrations of the solutions in the particles are analyzed by ICP-AES. For the consideration of the result of the experiments, we conducted thermodynamic equilibrium calculations. Calculation results support to investigate the chemical compounds of trace elements in the gasification atmosphere.</p>

DOI： 10.20550/jiesekitanronbun.54.0_2

Publishing type：Research paper (scientific journal)   Publisher：Energy and Fuels  

DOI： 10.1021/acs.energyfuels.6b00722

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：Energy and Fuels  

DOI： 10.1021/acs.energyfuels.5b02836

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：公益社団法人 化学工学会  

Flue gases contain elemental mercury formed by combustion/incineration processes, and it is difficult to remove them by conventional gas cleaning devices. Researchers have developed a few sorbent materials to capture gaseous elemental mercury. Our study also found two candidate sorbent materials using low-cost waste derived particles, a paper sludge incineration ash and a carbonized municipal solid waste char. The main objective of this study is to elucidate the capturing mechanisms of gaseous elemental mercury in these two sorbents. In order to analyze the chemical states of the mercury adsorbed on the sorbents, X-ray absorption near edge structure (XANES) analyses of the mercury captured by sorbents are conducted. The XANES spectra of the two sorbents were found to be similar to those of Hg₂Cl₂ and HgS standard chemicals, while the XANES spectrum of the commercialized activated carbon for mercury capture was similar to that of elemental mercury. These results suggest that the gaseous mercury is captured and fixed on the sorbents via oxidation by chlorine and sulfur present in the sorbents.

DOI： 10.1252/jcej.14we339

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：公益社団法人 化学工学会  

The objectives in the present study are to elucidate the fundamental gasification characteristics of woody biomass with a mixture gas of CO₂ and H₂O. The effects of temperature and gasification agents on the gasification characteristics of woody biomass were experimentally studied using an electrically heated drop tube furnace. The co-gasification performance of CO₂ with H₂O was compared with the CO₂ or H₂O gasification performance alone. As a result, H₂ and CO concentrations increased with an increase of temperature under both the co- and single-gasification conditions. CO under the co-gasification condition was produced more than under the single-gasification condition. The H₂ formation showed the opposite tendency to the CO formation during the co-gasification. This synergistic effect is caused by the difference of the surface structure of the woody biomass particles by CO₂ from H₂O.

DOI： 10.1252/jcej.14we338

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：Journal of Chemical Engineering of Japan  

DOI： 10.1252/jcej.16pr4903

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：Fuel Processing Technology  

DOI： 10.1016/j.fuproc.2015.08.040

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Auto-thermal updraft gasification of biomass pellets in a packed bed reactor was conducted by using air and air-steam mixture. Air-steam gasification produced syngas with slightly improved lower heating value of 4.5 MJ/m(N)(3), in comparison to 4.4 MJ/M-N(3) produced during air gasification. The corresponding tar generation for air gasification and air-steam gasification was 212 g/m(N)(3) and 26.2 g/m(N)(3), respectively. Cold gas efficiency for air gasification and air-steam gasification was realized to be 91% and 91.4%, respectively. Carbon conversion during air-steam gasification reached about 91.5% while carbon conversion during air gasification was limited to 84.3%. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fuproc.2015.07.015

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetokai.2016.65._519-1_

Publishing type：Research paper (scientific journal)   Publisher：The Iron and Steel Institute of Japan  

Coal contains harmful trace elements. Especially, mercury has high volatility. Mercury of approximately 27% in coals used in coal fired power plants is released as gaseous elemental mercury in a flue gas to the atmosphere. In an ironmaking system, since large amounts of coal are used as a reducing agent and heat source, there is a possibility that the gaseous elemental mercury emits from some processes. Therefore, an objective in this work is to develop adsorbents that are able to capture the gaseous elemental mercury in an air atmosphere and a reducing atmosphere. In this work, carbonized wastes (sewage sludge, paper sludge, woody biomass and municipal solid waste) were used as experimental samples. As a result, the municipal solid waste char has the highest property to capture the elemental mercury in the air atmosphere at 423 K. From results of X-ray Absorption Near Edge Structure (XANES) analyses, the mercury captured in the municipal solid waste char was mainly captured as mercury sulfide (HgS) on the char. On the other hand, a mercury capture ratio of the municipal solid waste char in the reducing atmosphere was lower than that in the air atmosphere.

DOI： 10.2355/tetsutohagane.TETSU-2015-046

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

One of the major problems in pulverized coal combustion process is ash deposit phenomena such as slagging and fouling. The behaviors of Included Minerals (IM) and Excluded Minerals (EM) are an important factor to predict and control such ash deposit phenomena. Then, we sampled pulverized coal particles in different carbon conversion and coal types using Drop Tube Furnace (DTF) and analyzed ash particles by Computer Controlled Scanning Electric Microscope (CCSEM) in previous study³⁾. In this study, we made the models of single pulverized coal particle in combustion process using data gotten by CCSEM analysis and evaluated IM/EM particle properties such as particle number, particle diameter and composition in different carbon conversion and coal types through the simulation.

DOI： 10.20550/jiesekitanronbun.53.0_6

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Coal combustion is one of the major mercury emission sources. The majority of mercury emissions from coal combustion is an elemental mercury. This is because oxidized mercury is water-soluble and easily captured, but on the other hand elemental mercury is water-insoluble and difficult to capture. In this study, we expected the De-NO_x catalyst to have a mercury capture/oxidation performance and performed mercury capture/oxidation experiment using the De-NO_x catalyst as a sorbent. In the result, when HCl is present in the atmosphere, the De-NO_x catalyst oxidized mercury and when HCl is not present in the atmosphere, the De-NO_x catalyst showed high mercury capture performance. Furthermore, De-NO_x catalyst maintained high mercury capture performance at a relatively high temperature (673 K).

DOI： 10.20550/jiesekitanronbun.53.0_4

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Oxy-Fuel coal combustion has drawn attention in the world as useful technique to achieve carbon dioxide capture and storage (CCS). It is a technology to enrich CO₂ in exhaust gas by the flue gas recirculation with additional pure O₂ to combustion atmosphere, which makes easy to capture CO₂. Meanwhile, bubbling fluidized bed coal combustion has advantages of direct sulfur capturing in bed material and decreasing of thermal NO_X in low combustion temperature. Objectives of this paper are to understand hazardous emission behaviors during the oxy-coal fluidized bed combustion under the actual flue gas recirculation condition, compared with those under the air and CO₂-O₂ combustion conditions. A lab-scale fluidized bed reactor was utilized as the experimental equipment. Dusts were separated from flue gas via cyclone downstream, and carbon contents in them were analyzed to estimate carbon balances through the reactor.

DOI： 10.20550/jiesekitanronbun.53.0_2

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：Fuel Processing Technology  

DOI： 10.1016/j.fuproc.2015.05.017

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Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：Fuel Processing Technology  

DOI： 10.1016/j.fuproc.2014.10.036

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：Fuel Processing Technology  

DOI： 10.1016/j.fuproc.2015.02.011

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetokai.2015.64._213-1_

Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 日本鉄鋼協会  

CO₂ emissions from blast furnaces should be reduced to curtail the impact of global warming. A promising solution is the low reducing agent rate (RAR) operation of blast furnaces. Char and ash particles derived from pulverized coal affect permeability in the furnace during low RAR operation. In our study, the combustion behavior and ash particle properties of pulverized coal during combustion were investigated. Char particles formed during combustion were sampled using a drop tube furnace, and then analyzed for their combustion ratio and ash particle properties. As a result, the combustion behavior of pulverized coal and properties of ash particles in raw coal were different by a coal type. Moreover, the combustibility of pulverized coal and the variation in ash particle properties during combustion were affected by the structure of the char particles.

DOI： 10.2355/isijinternational.55.1305

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In order to use the low-grade coals which are out of the power station requirement, blending of high-grade coals have been carried out in pulverized coal power station. However, for ash adhesion such as slagging and fouling, which is one of the important evaluation items of the coal, improvement of coal characteristics by the blending of coal does not become clear. It is necessary to establish the ash adhesion evaluation technology on the blending of the coal to reduce the cost of generation and increase availability of coal because most of low-grade coals are low ash fusion temperature. The purpose of this work is elucidation of ash deposition behavior at blended coal combustion. Ash deposits were collected on a heat transfer tube with an ash deposit experiment at some blend condition. In addition, we calculated the molten fraction of each blending condition by chemical equilibrium theory, using FactSage Ver.6.3.1 software.

DOI： 10.20550/jietaikaiyoushi.24.0_192

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

The purpose of this study is the gasification behavior of biomass in the packed-bed, carrying out gasification experiment (updraft and downdraft gasification). In this study, pellets of black pine (φ6.5 mm × 8.5 mm) were fed intermittently and using air as the gasification agent. In the gasification tests, the temperature distribution and the gas compositions in the gasifier were measured during gasification, and the amount of tar in the gasified gas was measured. In addition, the steam was injected in the gasifier in order to reduce the amount of tar.

DOI： 10.20550/jietaikaiyoushi.24.0_70

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Coal has better stability of price and supply compared to other fossil fuels. In particular, subbituminous coal is expected effective utilization because that has low cost and long minable years. However, subbituminous coal has the self-ignition risk that caused by reacting with oxygen in the air. Therefore, an objective of this study is the elucidation of oxygen adsorption properties of coal. Experimental samples are some kinds of the subbituminous coal and bituminous coal. In the oxygen adsorption experiments between 356K and 476K in 50%N_2-50%O_2 atmosphere, the amount of oxygen adsorption on the coal was determined by thermobalance. As a result, it is found that the oxygen adsorption amount of bituminous coal is larger than those of subbituminous coal and oxygen adsorption amount is correlated with the carbon content of the coal.

DOI： 10.20550/jiesekitanronbun.52.0_100

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Ash deposition behaviors on heat transfer tubes under blended coal combustion condition have been becoming one of important issues associated to recent pulverized coal-fired boilers. In this study, ash deposition experiments, using two ash samples from bituminous and subbituminous coals, at two different temperatures, 1050℃ and 1250℃, were carried out and the mass of ash deposition was measured. Deposited ash samples were solidified by epoxy resin, and then analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectrometer (EDX). In addition, fractions of liquid slag in ash were estimated by Thermo-equilibrium calculation to analyze ash melting characteristics.

DOI： 10.20550/jiesekitanronbun.52.0_56

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Some ash particles of biomass fuels adhere to heat exchanger tube surfaces, which causes some troubles such as heat transfer inhibition, operational problems and hot corrosion in incineration plants. In this study, the authors have developed a surface treatment technology of tubes via a thermal spraying technology and a corrosion-resistant coating to reduce the ash deposition and the hot corrosion. Both the results of 'High-temperature Corrosion Test' and 'Electrochemical Impedance Spectroscopy (EIS)' are exhibited in this paper. The major conclusions are drawn as follows: Polarization conductance of specimens can be evaluated by means of equivalent circuits which are assumed on the interface between specimens and simulated ash. Moreover, it is clear that EIS is available for evaluating the corrosion resistance.

DOI： 10.20550/jiesekitanronbun.52.0_52

Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the Combustion Institute  

DOI： 10.1016/j.proci.2014.08.029

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：Fuel  

DOI： 10.1016/j.fuel.2014.06.020

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：Fuel  

DOI： 10.1016/j.fuel.2013.07.050

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetokai.2014.63._328-1_

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Currently, one methods of recycling waste plastics include gasification. Gasification is carrying out thermal decomposition of the carbon resources, such as coal and the biomass for generating combustible gas. However, gasification will generate tar which is a mixture of polycyclic aromatic hydrocarbon. It generate as a by-product. If the amount of generation of tar can be reduced, failure of a gas engine can be prevented, and also generation gas can also be increased. So, in this research, by adding vapor as a gasifying agent, when gasifying a plastic, reduction of tar was aimed at and the gasification behavior was inquired using the Time of Flight Mass Spectrometry (TOFMS).

DOI： 10.20550/jietaikaiyoushi.23.0_276

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Some ash particles of solid fuels adhere to heat exchanger tube surfaces, which causes some troubles such as heat transfer inhibition, operational problems and hot corrosion in incineration plants. The authors have developed a surface treatment technology of tubes via a thermal spraying technique (TST) to reduce the ash deposition. Both the results of 'High-temperature corrosion test' and 'Alternating current impedance testing' were exhibited in this paper. The corrosion resistance of TST was evaluated by measuring the polarization conductance and weight loss in corrosive conditions. As a result, it was clear that some materials of TST have high corrosion resistance and the AC impedance testing is available for evaluating the corrosion resistance.

DOI： 10.20550/jietaikaiyoushi.23.0_260

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：一般社団法人 日本鉄鋼協会  

The price of caking coal, which is used in the production of metallurgical coke, has risen in recent years. Also of concern is the amount of CO₂ emitted from steel industries, comprising approximately 15% of total CO₂ emissions in Japan. Therefore, CO₂ emissions from the ironmaking process should be reduced to avoid global warming. In this work, fundamental research is conducted on the effect of adding woody biomass to the properties of coke, with the aim of possibly using woody biomass, which is carbon neutral, as a raw material in coke-making. Experimental results showed that the connectivity between coal particles in the coke sample during carbonization and coke strength drastically decrease by adding woody biomass to caking coal. However, the coke properties of the coke sample with added woody biomass could be improved by removing the partly volatile matter of woody biomass before mixing with caking coal, and as a result, the possibility of using woody biomass as a raw material for coke-making with prior carbonization at temperatures of more than 500°C was found.

DOI： 10.2355/isijinternational.54.2454

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

DOI： 10.1159/000437289

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Recently, the efficient use of coal has been increasingly developed as technologies against global warming issues. One of the solutions is a triple combined cycle system with coal gasification, such as IGFC (Integrated coal Gasification Fuel Cell combined cycle). SOFC (Solid Oxide Fuel Cell) is a key device in the system. however, trace elements in syn gas damage anodes of the SOFC. In this study, thermodynamics equilibrium calculation and power generation experiment are conducted to elucidate the reaction between anode materials and trace elements, such as As and Se.

DOI： 10.20550/jiesekitanronbun.51.0_118

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

One of the important purposes of the coke in the blast furnace is the spacer to ensure the gas and liquid permeability. In other hands, Ash particles in coke became slags inside the furnace and these are one of the causes that significantly worsen the permeability. in this study, combustion experiments of coke were conducted and ash particles in the coke samples were analyzed by using SEM/EDX in order to clarify ash particles behavior during combustion of coke.

DOI： 10.20550/jiesekitanronbun.51.0_8

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：Fuel  

DOI： 10.1016/j.fuel.2011.06.011

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Scopus

Publishing type：Research paper (scientific journal)   Publisher：Fuel Processing Technology  

DOI： 10.1016/j.fuproc.2011.09.009

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Atmospheric mercury emissions from coal combustion and waste incineration processes have been drawing attention as global pollutant. It has been reported that wet desulfurization process and/or absorbing bed of activated carbon, which are generally installed in domestic coal fired power plants, can control mercury emissions. However, considering the growing diversity of fuels including waste products and the overseas market development, a low-cost dry process for mercury removal from stack gas needs to be developed in near future. Objective in this study is to utilize particle materials derived from waste products to capture gaseous mercury. Mercury absorption experiments have bee n conducted using some mineral particles. As a result, calcined paper sludge showed the high performance for mercury absorption.

DOI： 10.1299/jsmeenv.2013.23.214

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetokai.2013.62.185

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Nano-sized organic aerosols, nanoparticles (d_p < 50 nm), in the atmosphere have attracted a lot of attention in recent years because of adverse effects on human health. A new system combining a soft plasma ionization (SPI) source with a time-of-flight mass spectrometer (TOFMS) has been successfully developed and applied to direct and on-line analysis of smoke generated during combustion. The mass spectra of smoke were obtained in conjunction with the effects of gas species (air, Ar and He), pressure (1600-2600 Pa) and current (10-130 mA) of the SPI discharge. To investigate the ionization mechanism of the SPI, we also have studied spontaneous emission spectra from the SPI source. Considering the results from mass and emission s pectral data, we suppose an ionization mechanism of the SPI which can efficiently produce excitation ofN_2 in the presence o f the noble gas, leading to promote ionization of sample.

DOI： 10.1299/jsmeenv.2013.23.222

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：Proceedings of the Combustion Institute  

DOI： 10.1016/j.proci.2012.08.009

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Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：2013 International Symposium on Micro-NanoMechatronics and Human Science, MHS 2013  

DOI： 10.1109/MHS.2013.6710484

Scopus

Publishing type：Research paper (scientific journal)  

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In pulverized coal combustion boiler, ash deposits such as slagging and fouling prevent heat transfer. On the other hand, a reserve of high lank coal is limited. So co-combustion of low lank coal, that is inexpensive, and high lank coal has been carried out in pulverized coal combustion boiler. Generally, low lank coal includes ash of low melting point. However, in this situation, ash deposition behavior has not been clarified. The purpose of this work is elucidation of ash deposition behavior during co-combustion in pulverized coal combustion boiler. Ash deposits were collected on a heat transfer tube with an ash deposit experiment at some blend condition. Ash particles near the adhesion interface were analyzed about element distribution by a Scanning Electron Microscope and an Energy Dispersive X-ray (SEM/EDX). And ash particles are also analyzed about composition and particle size distribution by a Computer Control Scanning Electron Microscope (CCSEM). We calculated the molten fraction of each mix condition ash by chemical equilibrium theory, using FactSage Ver.6.3.1 software.

DOI： 10.20550/jiesekitanronbun.50.0_52

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Recently, oxy-fuel coal combustion has drawn attention as useful technique to achieve carbon dioxide capture and storage (CCS). This is the technique that enriches CO_2 in exhaust gas by the flue gas recirculation with additional pure O_2 to combustion atmosphere, which makes easy to capture CO_2. 0n the other hand, bubbling fluidized bed coal combustion has advantages of direct sulfur capturing in furnace by adding desulfurizing agents to bed material and decreasing of thermal NO_x as a result of low combustion temperature. However, oxy-fuel combustion behavior of coal in a bubbling fluidized bed is still unclear. In this study, we conducted the coal burning experiment under CO_2/O_2 using bubbling fluidized bed and compared oxy-fuel combustion behavior with air combustion behavior of coal. In addition, three coal samples having different nitrogen contents were tested to estimate the effect of raw coal properties on oxy-fuel combustion behaviors.

DOI： 10.20550/jiesekitanronbun.50.0_56

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

In general, the use of coal having different physical properties from those of design coal in a pulverized coal combustion plant causes ash deposit troubles, such as fouling and slagging. However, from the viewpoint of utilization of low rank coals, flexibilities for various coal types as fuel are going to be required in pulverized coal fired boilers before long. Then, it is important to preliminarily predict mineral particle behaviors in coal combustion process. In this study, their behaviors are studied by use of artificial coal samples which contains included minerals and excluded minerals. Coal samples are burned in a drop tube furnace to sample particles in different conversion ratio and residence time. Then included and excluded minerals are analyzed and classified in particles by CCSEM

DOI： 10.20550/jiesekitanronbun.50.0_54

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Society of Chemical Engineers, Japan  

Boron compounds are generally highly volatile, and some of them vaporize in coal combustion and are contained in the flue gas. The partitioning behavior of boron from coal to the flue gas depends on the coal type, and the partitioning mechanisms are complex. In order to elucidate these mechanisms, it is necessary to develop a method to measure gaseous boron in coal combustion flue gas. In this study, we examined the absorption solution and sampling system material for gaseous boron compounds, using a model system of gaseous boron compounds and flue gas from a practical coal combustion facility. As a result, nitric acid with hydrogen peroxide was found to be the optimum solution for absorption. Silica glass or ethylene tetrafluoride resin were suitable materials for the sampling probe and line and the absorption impinger. Additionally, the sampling line must be kept at more than 130&deg;C in order to analyze the gaseous boron concentration accurately.

DOI： 10.1252/kakoronbunshu.38.183

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Coal and solid fuels derived from industrial wastes sometimes contain a small amount of mercury compounds. In conmbustion processes, gaseous elemental mercury passes through the stack and releases into the atmosphere. Mercury emissions in the combustion processes have been focused as one of upcoming air pollutants. In this work, it is the purpose to use wastes (sewage sludge, woody biomass and municipal waste) as an adsorbent of elemental mercury. We conducted mercury adsorption experiment used carbonized sewage sludge, carbonized biomass and carbonized municipal waste as adsorbents. As a result, the mercury adsorption ratio of carbonized municipal waste was the largest.

DOI： 10.1299/jsmeenv.2012.22.131

Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetokai.2012.61._403-1_

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

Web of Science

Publishing type：Research paper (scientific journal)   Publisher：The Japan Institute of Energy  

Currently, it becomes increasingly necessary to decrease CO_2 emissions from fossil fuel combustion processes, because they are major contributors to the global warming. Oxy-fuel coal combustion has drawn attention as useful technique to achieve carbon dioxide capture and storage (CCS). This is the technique that enriches CO_2 in exhaust gas by the flue gas recirculation with additional pure O_2 to combustion atmosphere, which makes easy to capture and liquidize CO_2 downstream. However, there have been few reports about behaviors of various environmental pollutants in oxy-fuel coal combustion with the flue gas recirculation. In this study, we experimentally estimated effects of NO and N_2O recirculation with CO_2 by a drop tube furnace equipment. In addition, we simulated NO and N_2O formations under oxy-fuel coal combustion condition by elementary reaction analysis, and then we discussed mechanism for the formation of NOX.

DOI： 10.20550/jiesekitanronbun.49.0_42

Publishing type：Research paper (scientific journal)  

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

Web of Science

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)   Publisher：Fuel  

DOI： 10.1016/j.fuel.2011.06.041

Web of Science

Scopus

Publishing type：Research paper (scientific journal)