Faculty Profiles - NARUSE Ichiro

The role of post-pyrolysis carbon dioxide capture in hydrogen recovery from waste-derived pyrolysis gas

Wang, YX; Veksha, A; Ong, J; Ueki, Y; Yoshiie, R; Naruse, I; Lisak, G

FUEL Vol. 381 2025.2

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

The study elucidated the role of post-pyrolysis CO2 removal using a CaO sorbent on upgrading pyrolysis gas into H2-rich gas. The pyrolysis gas was obtained from various waste-derived feedstocks (municipal sewage sludge, refused derived fuel (RDF), pine sawdust (biomass), and marine litter) by pyrolysis (600 °C), and underwent the treatment with CaO (600 °C) followed by the thermolytic decomposition at 1300 °C. The results show that CaO utilization does not change significantly H2 yield and higher heating value of gas on a feedstock mass basis but increases H2 purity from 49.6–83.3 to 63.7–94.4 vol% and H2/CO ratio from 1.1–5.7 to 1.9–19.8 of the product gas across all feedstocks. Normalized rate constants K for CO2 capture by CaO, determined by the grain model, varied between 0.0001 and 0.0006 min−1, revealing the feedstock-specific effectiveness of CaO. The higher CaO consumption rates were observed in case of RDF and biomass compared to sludge and marine litter. This could be attributed to the coking and faster carbonation of CaO caused by the composition of pyrolytic products. The obtained results emphasize the potential of integrating CaO sorbent into pyrolysis-based processes for the production of decarbonized H2-rich gas with higher purity. Moreover, the use of normalized kinetic parameters provides a straightforward method for the selection of feedstocks suitable for decarbonization of pyrolysis gas using CaO sorbent. The predominant factor affecting the carbonation kinetics of the CaO sorbent was found to be the CO2 flow rates in their respective pyrolysis gases.

DOI： 10.1016/j.fuel.2024.133293

Effect of temperature on reaction and degradation behaviors during CO2 and H2O gasification reactions of coke in same conversion ratio

Zheng Zhenjie, Ueki Yasuaki, Naruse Ichiro

ISIJ International Vol. advpub ( 0 ) 2025

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

The efficiency of blast furnaces is adversely affected by coke degradation via gasification. Considering the utilization of hydrogen-enriched blast furnaces, it is essential to investigate the reaction and degradation behaviors of coke at different temperatures. In this study, coke gasification experiments were conducted under CO2 and H2O atmospheres at different temperatures to prepare cokes with a conversion ratio of 0.2. The reaction rate of the H2O gasification reaction was higher than that of the CO2 gasification reaction at the same temperature. The activation energies for CO2 and H2O gasification were 150.2 and 126.0 kJ/mol, respectively. After gasification, the shrinkage ratio was low by H2O gasification at 1273 K and increased with increasing temperature, indicating that the surface reaction became the control factor that consumed the coke matrix with increasing temperature. On the other hand, the shrinkage ratio by CO2 gasification tended to be stable from 1273 to 1673 K. Furthermore, the increase in the porosity of coke by H2O gasification was lower than that by CO2 gasification at higher temperatures. In addition, the strength of the coke via H2O gasification was higher than that of the coke via CO2 gasification.

DOI： 10.2355/isijinternational.isijint-2024-344

O-05　Evaluation of ash agglomeration in fluidized-bed combustion of biomass fuels

TAUCHI Nozomi, MIYASHITA Kazuhiro, SHIGETA Jun-ichi, DEMACHI Toyoko, UEKI Yasuaki, NARUSE Ichiro

Proceedings of the Conference on Biomass Science Vol. 20 ( 0 ) page： 9 - 10 2024.12

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

Biomasses are focused on as one of alternative fuels, and are generally burned in circulating fluidized bed systems, which have fewer restrictions on fuel types and their shapes. However, agglomeration occurs inside the bed due to the reaction between silica sand as fluidizing material with ash containing in the biomass at high temperatures. In this study, the reaction characteristics between the silica sand and the ash particles are tested, using a small-scale packed bed, and are calculated by means of chemical equilibrium theory under the conditions with different ash properties. As a result, the actual agglomeration characteristics agrees well with fraction of the formation of molten slag calculated.

DOI： 10.20550/jiebiomassronbun.20.0_9

O-10　CO2 gasification characteristics of woody biomass in packed bed gasifier

HASEGAWA Shoichi, DEMACHI Toyoko, UEKI Yasuaki, NARUSE Ichiro, YOSHIIE Ryo

Proceedings of the Conference on Biomass Science Vol. 20 ( 0 ) page： 19 - 20 2024.12

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

To improve energy conversion efficiency, it is effective to convert solid biomass into gaseous fuel by gasification. However, tar emission during gasification process is crucial problem as it causes mechanical troubles in gas engines downstream. Therefore, it’s important to elucidate tar emission behavior and lower emission mass. To lower tar emission, we considered that CO2 reforming in packed bed gasifier of tar might be effective, so we conducted CO2 gasification experiment. In the experiment, we analyzed syngas yields and sampled tar using Small packed bed reactor.

DOI： 10.20550/jiebiomassronbun.20.0_19

O-06　Modeling and Elucidation of Combustion Behavior of Various Biomass Fuels

TAKAHASHI Kota, DEMACHI Toyoko, UEKI Yasuaki, NARUSE Ichiro, YOSHIIE Ryo, MATSUNARI Shohei

Proceedings of the Conference on Biomass Science Vol. 20 ( 0 ) page： 11 - 12 2024.12

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

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.

DOI： 10.20550/jiebiomassronbun.20.0_11

Degradation of solid oxide fuel cell anodes by the deposition of potassium compounds Open Access

Zhang, H; Yoshiie, R; Naruse, I; Ueki, Y

CARBON RESOURCES CONVERSION Vol. 7 ( 4 ) 2024.12

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

1-01　Pulverization behaviors during gasification reaction of coke at high temperatures

ZHENG Zhenjie, UEKI Yasuaki, DEMACHI Toyoko, NARUSE Ichiro

Proceedings of Conference on Coal Science Vol. 61 ( 0 ) page： 2 - 3 2024.10

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

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 CO2 and 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.

DOI： 10.20550/jiesekitanronbun.61.0_2

2-12　Technologies for reduction of ash deposition and high-temperature corrosion in Waste-to-Energy Plants

NAGANUMA Hiroshi, SAWADA Akihiro, MORI Takehito, GOTO Taeko, KOSAKA Sachie, NARUSE Ichiro

Proceedings of Conference on Coal Science Vol. 61 ( 0 ) page： 52 - 53 2024.10

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

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.

DOI： 10.20550/jiesekitanronbun.61.0_52

1-11　Behaviors of Cl deposit on heat transfer tubes in biomass combustors

WADA Chikako, SATO Naoki, WATANABE Kazuhiro, NARUSE Ichiro

Proceedings of Conference on Coal Science Vol. 61 ( 0 ) page： 22 - 23 2024.10

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

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.

DOI： 10.20550/jiesekitanronbun.61.0_22

Comparative life cycle assessment of organic industrial solid waste co-disposal in a MSW incineration plant

Liu, YH; Li, AJ; Guo, GZ; Zhang, JW; Ren, Y; Dong, L; Gong, LF; Hu, HY; Yao, H; Naruse, I

ENERGY Vol. 305 2024.10

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

3-3-2　Reduction behaviors of iron oxide by waste plastics and woody biomass

KADA Kohei, DEMACHI Toyoko, UEKI Yasuaki, NARUSE Ichiro, YOSHIIE Ryo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 33 ( 0 ) page： 58 - 59 2024.7

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

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.

DOI： 10.20550/jietaikaiyoushi.33.0_58

5-2-1　Ash melting behaviors and ash adhesion control technology for energy recovery of industrial waste

MUKOMOTO Shun, DEMACHI Toyoko, UEKI Yasuaki, NARUSE Ichiro, YOSHIIE Ryo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 33 ( 0 ) page： 148 - 149 2024.7

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

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.

DOI： 10.20550/jietaikaiyoushi.33.0_148

Processing plastic waste via pyrolysis-thermolysis into hydrogen and solid carbon additive to ethylene-vinyl acetate foam for cushioning applications

Wang, YX; Chang, BP; Veksha, A; Kashcheev, A; Tok, ALY; Lipik, V; Yoshiie, R; Ueki, Y; Naruse, I; Lisak, G

JOURNAL OF HAZARDOUS MATERIALS Vol. 464 page： 132996 2024.2

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

Ash deposition and corrosion mechanisms of tubes in Waste-to-Energy plants

PubMed

NAGANUMA Hiroshi, MORI Takehito, WATANABE Sho, SAWADA Akihiro, GOTO Taeko, UEKI Yasuaki, YOSHIIE Ryo, NARUSE Ichiro

Mechanical Engineering Journal Vol. 11 ( 2 ) page： 23-00486 - 23-00486 2024

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

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.

DOI： 10.1299/mej.23-00486

Mechanism of arsenic migration and transformation during pulverized coal combustion

Huang, YD; Li, AJ; Hu, HY; Li, S; Zou, C; Zou, RJ; Wu, XJ; Naruse, I; Yao, H

PROCEEDINGS OF THE COMBUSTION INSTITUTE Vol. 40 ( 1-4 ) 2024

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

Influence mechanism of chlorine on arsenic release and transformation during municipal solid waste incineration

Li, S; Hu, HY; Zou, C; Dong, L; Huang, YD; Liu, H; Naruse, I; Yao, H

PROCEEDINGS OF THE COMBUSTION INSTITUTE Vol. 40 ( 1-4 ) 2024

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

Electrochemical characteristics of solid oxide fuel cells supplied with CO-rich fuel gases Open Access

ZHANG Hui, ONOGI Rui, YOSHIIE Ryo, UEKI Yasuaki, NARUSE Ichiro

Journal of Thermal Science and Technology Vol. 19 ( 1 ) page： 23-00525 - 23-00525 2024

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

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.

DOI： 10.1299/jtst.23-00525

Mechanism of ash deposition in industrial waste treatment furnaces and its control

Nii Daiki, Demachi Toyoko, Ueki Yasuaki, Naruse Ichiro, Yoshiie Ryo

Proceedings of the Annual Conference of Japan Society of Material Cycles and Waste Management Vol. 35 ( 0 ) page： 395 2024

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

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.

DOI： 10.14912/jsmcwm.35.0_395

Elucidation of release behaviors of volatile matter for various types of biomass particles by chemical kinetic analysis

MATSUNARI Shohei, TAKAHASHI Kodai, UEKI Yasuaki, YOSHIIE Ryo, NARUSE Ichiro

The Proceedings of the National Symposium on Power and Energy Systems Vol. 2024.28 ( 0 ) page： A113 2024

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

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.

DOI： 10.1299/jsmepes.2024.28.a113