Faculty Profiles - NORINAGA Koyo

Mechanism investigation of direct electrochemical reduction of CO2-loaded 2-(ethylamino)ethanol solution into CO Reviewed

Dai, RC; Zhang, LJ; Tran, KVB; Sirisomboonchai, S; Machida, H; Norinaga, K

SEPARATION AND PURIFICATION TECHNOLOGY Vol. 355 2025.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Separation and Purification Technology

Carbon capture and utilization (CCU) has attracted considerable interest recently as CO2 emission and global warming have greatly affected various aspects of the environment, economy, and society. However, energy consumption during CCU must be substantially reduced. In this study, we propose an alternative approach using electrochemical reduction to directly convert CO2-loaded amine solutions into CO. The effects of the electrodes, temperature, potential, and CO2 loading on the Faradaic efficiency (FE) of CO were comprehensively investigated. The Ag NPs/CP electrode showed good catalytic performance on the electrochemical reduction of CO2-loaded amine solution to CO. By comparing the chemical composition in the solution before and after the electrochemical reaction, we determined that the main source of CO might be free CO2, which is mainly converted from bicarbonate rather than carbamate. In addition, electrochemical impedance spectroscopy was used to investigate the resistance during the reaction. The electric double-layer was found over the electrode surface when different amine solutions were used as the electrolyte. The spatial structure of ammonium cations and carbamate plays a key role in the FE of CO in this process.

DOI： 10.1016/j.seppur.2024.129575

Design of an efficient CO<inf>2</inf> methanation process and techno-economic analysis with CO<inf>2</inf> capture from the flue gas of automotive shredder residue Reviewed

Wasnik C.G., Nakamura M., Machida H., Ito J., Shiratori K., Norinaga K.

Chemical Engineering Journal Vol. 507 2025.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Engineering Journal

Recycling and utilizing automotive shredder residue (ASR) is necessary for realizing a sustainable automotive industry. This study conducted a feasibility analysis using a process simulator for Case I, where fuel gas is produced through the gasification of ASR followed by combined heat and power generation using a gas engine, CO2 capture from exhaust gas through chemical absorption, and production of synthetic methane (CH4) using the captured CO2 and renewable hydrogen produced via water electrolysis powered by renewable energy sources. This process produces not only CH4 but also surplus electricity, which can be used to produce H2 or power adjacent equipment. Case II, where fuel gas obtained from ASR gasification was directly methanated, was considered for comparison. This study compared the economic potential of both processes for kiln-type ASR gasification that can process 1,200 kg-ASR/h to produce 3,350 Nm3/h of fuel gas. Case I produced 4,800 tons/year of CH4 with an energy efficiency of 46.5 %, whereas Case II produced 2,720 tons/year. The levelized production cost of methane in 2050 can be estimated at $1,241/ton and $1,568/ton for Cases I and II, respectively, which are lower than the expected cost of natural gas in market environments by 2050. This study highlights the potential of ASR-derived CO2 methanation as a carbon–neutral technology that can effectively achieve carbon conversion while producing high-value synthetic methane.

DOI： 10.1016/j.cej.2025.160737

CO<inf>2</inf> methanation over low-loaded Ni-M, Ru-M (M = Co, Mn) catalysts supported on CeO<inf>2</inf> and SiC Reviewed Open Access

Wasnik C.G., Nakamura M., Shimada T., Machida H., Norinaga K.

Carbon Resources Conversion Vol. 8 ( 1 ) 2025.3

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

The concentration of the major greenhouse gas CO2 is rapidly increasing in the atmosphere, leading to global warming and a range of environmental issues. An efficient circulation and utilization of CO2 is critical in the current environmental context. Methanation, an exothermic process, emerges as a critical strategy for effective CO2 utilization. On this front, there is a significant demand for rational design of catalysts that maintain high activity and methane selectivity over a wide temperature range (250–550 °C). The catalyst that can promise a consistent reaction even at 500 °C under an atmospheric pressure is thus obliged. The present study investigated bimetallic catalysts with SiC, which is known for its exceptional thermal conductivity, and CeO2, which is characterized by its CO₂ affinity, as base materials. We incorporated Ni-M and Ru-M (M = Co and Mn) as the active metals, each loaded at 2 %. Impressively, with merely 20 mg, the Ni-Co/SiC catalyst achieved a CO2 conversion rate of 77 % and CH₄ selectivity of 88 % at 500 °C, in a fixed-bed tubular reactor system with conditions of H2/CO2 = 4, a total flow rate of 70 ml min−1, and a steady GHSV of 12,000 h−1. Moreover, 2Ni-2Co/CeO2 catalyst demonstrated exceptional performance with a 76 % conversion of CO2 and a 83 % selectivity for CH4, all under identical conditions. The catalyst's durability was confirmed by a subsequent 40-hour stability test, which showed only a 3–5 % degradation. The developed catalysts were comprehensively characterized by BET/BJH, CO pulse chemisorption, H2-TPR, HAADF-STEM-EDS, SEM-EDS and XRD etc. to unveil their physicochemical and surface traits. It was found that Co and Mn, when integrated, effectively restrained the agglomeration of Ni and Ru particles, ensuring optimal metal dispersion on the support. In conclusion, our synthesized bimetallic catalysts shown a sustained catalytic capability, even in the high-temperature environment.

DOI： 10.1016/j.crcon.2024.100241

Open Access

Observation and kinetic modeling of carbon dioxide deposition under reduced pressures at cryogenic temperatures Reviewed Open Access

Xiao, SW; Hirayama, M; Machida, H; Norinaga, K

CHEMICAL ENGINEERING SCIENCE Vol. 305 2025.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Engineering Science

Liquefied natural gas (LNG) is typically vaporized through heat exchange with seawater or other sources and used as city gas or power generation fuel, but its cold energy remains underutilized. This study proposes a new CO2 capture process leveraging LNG's cryogenic temperatures to create a vacuum environment, recovering CO2 from amine-based solutions as dry ice. CO2 deposition under cryogenic and vacuum conditions was observed, and a deposition rate model was developed. In the experiment, liquid nitrogen circulated through the tube side of a glass vertical single-tube shell-and-tube heat exchanger (230 mm long), while CO2 was supplied to the shell side. CO2 was deposited on the outer surface of a 5-mm diameter tube, with its growth rate measured by a laser displacement sensor. At 293 K and pressures of 140–1000 Pa, experimental results matched a rate model based on energy balance and mass transfer.

DOI： 10.1016/j.ces.2024.121177

Open Access

Nickel/Zirconia-Catalyzed CO2 Methanation in Differential and Integral Fixed-Bed Reactors: Experimental and Computational Fluid Dynamics Studies Reviewed

Shimada, T; Nakamura, M; Fukumoto, K; Ibrahim, M; Wasnik, CG; Machida, H; Norinaga, K

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH Vol. 64 ( 3 ) page： 1473 - 1487 2025.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Industrial and Engineering Chemistry Research

Isothermal conditions and a chemical-kinetics-limited rate should be maintained when measuring the reaction rates of gases on solid catalysts. However, in highly exothermic reactions─such as the Sabatier reaction─temperature variations within the catalyst bed make it challenging to achieve isothermality. In this study, temperature changes in a Ni/ZrO2 catalyst bed were minimized using α-Al2O3 diluent and high gas hourly space velocities (GHSVs) to achieve low feed gas conversion (differential conditions: 0.9 MPa; 523-873 K; GHSV = 7600-30,000 L/h/g cat). The temperature profile within the catalyst bed was obtained by coupling a previously reported kinetic model with three-dimensional computational fluid dynamics (CFD) simulations. Experiments were also conducted under integral conditions at low GHSVs, resulting in high conversion rates and heat release. CFD simulations accurately reproduced the experimental feed gas conversion and temperature, suggesting that the CFD-simulation-guided kinetic parameters appropriately predicted the methanation characteristics at practically relevant high conversion rates.

DOI： 10.1021/acs.iecr.4c03789

CFD simulation of crude oil fouling from laboratory- to industrial-scale heat exchangers using a weak coupling approach Reviewed

Fukumoto, K; Zhang, W; Choi, C; Tang, F; Machida, H; Norinaga, K

APPLIED THERMAL ENGINEERING Vol. 258 2025.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Thermal Engineering

Crude oil fouling is described as an accumulation of unwanted materials such as asphaltene and metallic salt on a heat transfer surface in a pre-heat train of the crude distillation unit in oil refineries, causing an economic loss of 1–1.2 billion U.S. dollars per year in 2019. Computational fluid dynamics is one of the useful simulation tools for numerical research on this topic. However, crude oil fouling is a long-term phenomenon; therefore, the time scale is longer than general computational fluid dynamics problems. The fouling layer in oil refineries grows over several months to several years despite the small pipe diameter of several or several tens of millimetres. For this reason, it is not easy to satisfy the Courant–Friedrichs–Lewy condition. To overcome this problem, we developed a new algorithm based on a weak coupling approach, validated this scheme, and exhibited the application of this technology. In the new algorithm, momentum and pressure fields and enthalpy and mass fraction fields are solved separately. The algorithm was implemented as FoulingFOAM, a crude oil fouling simulator based on OpenFOAM v2006. Then, the solver was first validated with the lab-scale measurements, showing good agreement with the experimental data. Next, industrial-scale data in the two refineries were simulated for validation. It was possible to predict the peak fouling resistance against time. Finally, for both lab- and industrial-scale simulations, the predictions of our numerical tool showed that fouling resistance increased with higher wall temperature, lower crude oil velocity, and higher concentration of fouling species, which were identical to previous measurements. Hence, we concluded that the weak coupling approach is promising for investigating crude oil fouling problems.

DOI： 10.1016/j.applthermaleng.2024.124614

A New Method to Observe the Internal Amine Distribution in an Amine-Functionalized Resin Sorbent Particle Reviewed

Xu C., Liu P., Peng Y.L., Dou M., Jiang Q., Jia X., Zhang Y., Norinaga K.

Industrial and Engineering Chemistry Research 2025

Language：English Publishing type：Research paper (scientific journal) Publisher：Industrial and Engineering Chemistry Research

Understanding the amine distribution within solid amine sorbents is crucial for enhancing their amine utilization and ultimately improving the CO2 adsorption capacity. However, suitable characterization methods are lacking. To address this, a novel method was proposed to visualize the distributions of total and accessible amine content within the sorbent particles. In this method, SO2 was selected to label the accessible amine, while scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS) were used to measure the nitrogen and sulfur content, which were further used to calculate the total amine and accessible amine content, respectively. By this method, the total amine content is found to be evenly distributed, which is also higher than the accessible amine content due to the utilization of nitrogen for cross-linking and the diffusion resistance within the particles. For particle sizes larger than a critical size, accessible amine content is higher near the wall and lower at the core. This gradient becomes less pronounced as particle size decreases and becomes uniform when particle size is below this critical size. Therefore, reducing the particle size of solid amine sorbents to below the critical size range (e.g., 250-338 μm in this study) can effectively enhance CO2 adsorption capacity by maximuming the accessible amine cont within the sorbent particles.

DOI： 10.1021/acs.iecr.4c05007

1-07　Techno-Economic Analysis on Synthesis of Tetrahydrofurfuryl Alcohol by Furfural Hydrogenation Reviewed

UEHARA Yusuke, LI Qiao, RAO Thuppati Upender, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 61 ( 0 ) page： 14 - 15 2024.10

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

Efficient conversion of biomass-derived furfural into high value-added chemicals such as tetrahydrofurfuryl alcohol (THFA) by hydrogenation has received much attention in terms of post-fossil fuel and energy saving. While many researchers have put their efforts on developing cost-effective catalysts for furfural hydrogeneration, only little investigations have been reported on its techno-economic analysis as well as process optimization. This study aims to design an energy saving process model of furfural hydrogeneration for THFA synthesis coupled with thermal recovery system consisting of organic Rankine cycle and heat pump, and to evaluate energy efficiency and economics of the proposed process through Aspen simulation, based on our previous experimental data with Ni1Cu1-Al1 catalyst.

DOI： 10.20550/jiesekitanronbun.61.0_14

1-03　Conversion of carbon dioxide to ethylene by electrolytic reduction using perovskite catalysts Reviewed

Suchada SIRISOMBOONCHAI, Norinaga KOYO

Proceedings of Conference on Coal Science Vol. 61 ( 0 ) page： 6 - 7 2024.10

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

The electrochemical CO2 reduction reaction (eCO2RR) offers a sustainable method for reducing greenhouse gas emissions by converting CO2 into valuable chemicals and fuels without requiring extreme conditions. Electrocatalysts play a significant role in this process by producing carbon-based products such as ethylene, etc. Perovskite oxides have emerged as promising electrocatalysts due to their high ionic/electronic structure, stability, ability to vary elements, and the alkaline earth effect, which enhances the *CO2 - intermediate. Specifically, Ca is the A-site in coordination with the Cu-site, providing Ca2CuO3 with strong basic strength and exceptional CO2 adsorption capabilities. The Ca2CuO3 catalyst demonstrates significant efficiency in converting CO2 to C2H4, exceeding FEC2H4 50% at 100 mA/cm2. This research represents an attractive advancement in realizing the conversion of CO2 to C2H4.

DOI： 10.20550/jiesekitanronbun.61.0_6

Design and Optimization of Large-Scale Green Liquid Hydrogen Production Integrated with Heat Recovery and Absorption Precooling Reviewed

Li, Q; Machida, H; Norinaga, K

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH Vol. 63 ( 44 ) page： 19063 - 19075 2024.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Industrial and Engineering Chemistry Research

Liquid hydrogen (LH2) presents a viable solution for energy storage and transportation, particularly when produced by using renewable electricity. In this study, the energy efficiency of large-scale PEM water electrolysis for hydrogen production was investigated to be 59.74%, with the levelized electricity cost of hydrogen of 57.48 kWh/kg. To recover the waste heat from the PEM electrolyzer, two heat integration approaches have been proposed: the organic Rankine cycle (ORC) and the absorption refrigeration cycle (ARC). The ORC converted waste heat into electricity, while the ARC generated cold energy to precool the refrigerant, alongside electricity generation, both of which reduced energy consumption in the hydrogen liquefaction process. Subsequently, the process parameters were optimized through Matlab with the Mesh Adaptive Direct Search algorithm aimed at minimizing the specific energy consumption (SEC) of hydrogen liquefaction integrated with ORC or ARC, resulting in SECs of 6.76 and 6.61 kWh/kg LH2, with 21.33% and 22.87% reductions compared with the liquefaction process without heat recovery, respectively. The corresponding exergy efficiencies were 56.96% and 57.16% for the liquid hydrogen production process, with 86.69% and 87.73% for the hydrogen liquefaction process, respectively.

DOI： 10.1021/acs.iecr.4c02383

P-4-5　Investigation of numerical conditions for heat transfer in a CO2 sublimation tank Reviewed

YAMAGUCHI Hiroyasu, UEHARA Yusuke, MACHIDA Hiroshi, NORINAGA Koyo, SAITO Yasuhiro

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 33 ( 0 ) page： 244 - 245 2024.7

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

Numerical simulations for cooling of CO2 gas around a cold plate in a laboratory-scale sublimation tank were performed to investigate the effect of the heat flux from the plate and the initial temperatures of the CO2 gas on the temperature distribution. The results showed that the heat flux of the plate had a minimal impact on the temperature distribution in the tank. The effect of the heat of sublimation of CO2 on the temperature distribution in the tank would be significantly large.

DOI： 10.20550/jietaikaiyoushi.33.0_244

6-2-4　Development of Atomically Dispersed Ni Catalyst on N-doped Carbonized Lignin for Highly Efficient Electrochemical CO2 Reduction Reviewed

Park Gi-Dong, Suchada Sirisomboonchai, Norinaga Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 33 ( 0 ) page： 166 - 167 2024.7

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

The Ni single-atom catalysts (SACs) on N-doped carbon are promising electrocatalyst for the electrochemical CO2 reduction (CO2R), owing to their unique electrocatalytic properties. However, conventional methods to fabricate SACs are not environmentally friendly. To overcome it, we utilized lignin for preparing Ni SAC, which is derived from biomass. Furthermore, the coordination number of Ni−NxC sites was regulated to investigate the effects of change in geometrical/electronic nature on catalytic behaviors. The Ni SAC on lignin-derived N-doped carbon performed an CO Faradaic efficiency of 98.2 % at −0.9 V vs. RHE, in H-type cell configuration. Along with experimental results, DFTbased theoretical calculations elucidated the reasons for the enhanced CO2R performance, depending on the different coordination environments of Ni−NxC sites.

DOI： 10.20550/jietaikaiyoushi.33.0_166

6-2-2　Study on methane synthesis process using treated gas from automobile shredder dust as feedstock Reviewed

Nakamura Maki, Li Qiao, Chopendra G. Wasnik, Norinaga Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 33 ( 0 ) page： 162 - 163 2024.7

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

This study proposes a rational process aimed at carbon recycling to effectively recycle carbon dioxide (CO2) emitted from automobile shredder residue (ASR). The methods investigated include direct methane synthesis from ASR process gas and methane synthesis from CO2 recovered by chemical absorption using a gas engine cogeneration system. By optimizing the type and operating conditions of these reactors, it was found that the methane synthesis cost can be reduced by using CO2 recovered through chemical absorption in the methane synthesis process.

DOI： 10.20550/jietaikaiyoushi.33.0_162

6-2-3　Development Of CO2 Methanation Catalysts Supported On CeO2 And SiC At Elevated Temperatures Reviewed

Chopendra G. Wasnik, Nakamura Maki, Shimada Taiki, Machida Hiroshi, Norinaga Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 33 ( 0 ) page： 164 - 165 2024.7

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

The increasing concentration of CO2 in the atmosphere is a major environmental concern, and effective utilization of CO2 is crucial. In this context, efficient circulation and utilization of CO2 are paramount. The methanation process emerges as a critical strategy for effective CO2 utilization. The methanation is an exothermic reaction. Therefore, catalysts that uphold high activity and methane selectivity over a wide temperature range are in significant demand. This study investigated 2Ni-2Co/SiC and 2Ni-2Co/CeO2 bimetallic catalysts, using only 20 mg of the sample. The experiments were carried out in a fixed-bed tubular reactor at a steady GHSV of 12,000 h-1. The results showed that the catalyst 2Ni-2Co/SiC showed 77% conversion of CO2 with an 88% CH4 selectivity, while 2Ni-2Co/CeO2 demonstrated 76% CO2 conversion and 83% selectivity for CH4 at 500°C. These bimetallic catalysts have high activity for Ni and Ru, with resistance to Co and Mn carbon deposition, and can withstand high temperatures up to 500°C without losing activity, selectivity, and thermal stability. The catalysts were characterized through multiple tests, to unveil their physicochemical properties. The Co and Mn have effectively restrained the Ni and Ru agglomeration, optimized metal dispersion, and enhanced catalytic activity even in high-temperature environments.

DOI： 10.20550/jietaikaiyoushi.33.0_164

LNG Oxy-Fuel Power and Green Methanol Poly Generation Systems Associated with CO2 Condensation Capture: Techno-Economic Environmental Assessment Reviewed

Discussion Reviewed

NODA Reiji, NORINAGA Koyo, FUSHIMI Chihiro, ENOMOTO Hiroshi, HOSOKAI Sou, OTA Tomohisa

Nihon Enerugii Gakkai Kikanshi Enermix Vol. 103 ( 4 ) page： 422 - 431 2024.7

Li, Q; Machida, H; Feng, ZM; Norinaga, K

ENERGY & FUELS Vol. 38 ( 14 ) page： 13089 - 13103 2024.7

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

To achieve energy-environment synergy and sustainability, this study proposes a poly generation system that integrates the energy release process of liquefied natural gas (LNG) oxy-fuel power generation with the energy storage process of green methanol synthesis from renewable energy. In this system, oxygen, the byproduct of water hydrolysis to hydrogen, can support LNG oxy-fuel power generation; while the cold energy released during LNG regasification can serve as a cold source for carbon capture, the captured CO2 can be utilized as the carbon source for methanol synthesis, thus realizing cleaner methanol production and an efficient power generation process with near-zero carbon emission. Following the process design, the parameters were optimized with minimum levelized production cost of methanol and electricity as the objective function through Matlab using the “MADS” algorithm, resulting in 683.79 $/tonne and 68.05 $/MW h, respectively, with overall exergy efficiency of 50.28%. Notably, as green methanol synthesis requires additional CO2, a reduction of 2272.59 kg/h can be achieved. The study concludes that the novel poly generation process is superior in exergy efficiency and CO2 capture and utilization but inferior in high production costs.

DOI： 10.1021/acs.energyfuels.4c01250

Energy optimization of a non-aqueous solvent CO2 absorption system with pressure swing regeneration Reviewed

Environmental-friendly extraction of di(2-ethylhexyl) phthalate from poly (vinyl chloride) using liquefied dimethyl ether Reviewed Open Access

Wang, T; Kanda, H; Kusumi, K; Mei, L; Zhang, LJ; Machida, H; Norinaga, K; Yamamoto, T; Sekikawa, H; Yasui, K; Zhu, L

WASTE MANAGEMENT Vol. 183 page： 21 - 31 2024.6

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

Poly(vinyl chloride) (PVC) is one of the most widely used plastics. However, a major challenge in recycling PVC is that there is no economical method to separate and remove its toxic phthalate plasticizers. This research made a breakthrough by extracting PVC with liquefied dimethyl ether (DME) and successfully separating the plasticizer components. Nearly all (97.1 %) of the di(2-ethylhexyl) phthalate plasticizer was extracted within 30 min by passing liquefied DME (285 g) through PVC at 25 °C. The compatibility of PVC with organic solvents, including liquefied DME, was derived theoretically from their Hansen solubility parameters (HSP), and actual dissolution experiments were conducted to determine the optimal PVC solvents. A liquefied DME mixture was used to dissolve PVC, and the extract was diluted with ethanol to precipitate the dissolved PVC. We demonstrated that liquefied DME is a promising method for producing high quality recycled products and that the process retains the fundamental properties of plasticizers and PVC without inducing degradation or depolymerization. Because of its low boiling point, DME can be easily separated from the solute after extraction, allowing for efficient reuse of the solvent, extracted plasticizer, and PVC. DME does not require heat and produces little harmful wastewater, which significantly reduces the energy consumption of the plasticizer additive separation process.

DOI： 10.1016/j.wasman.2024.04.050

Chairunnisaa; Zhou, YX; Wu, YT; You, C; Thu, K; Miyazaki, T; Uehara, Y; Machida, H; Norinaga, K

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol. 135 2024.6

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Greenhouse Gas Control

This study focuses on optimizing the energy requirement in the post-combustion CO2 capture system using pressure swing regeneration through a model-based design (MBD). The simulation results highlight the significant impact of CO2 recovery, inlet gas and liquid flow rate, and CO2 concentration in the flue gas on the overall energy demand of the system. Moreover, an investigation into the de-sublimation chamber was undertaken, revealing a relationship between dry ice formation and the heat transfer between the LNG stream and CO2 in the heat exchanger. The parametric analysis study reveals that the sensible heat of the lean solvent is significantly influenced by the CO2 concentration in the liquid, consequently affecting the overall system energy. According to the results, the utilization of cold energy from LNG could save 80 % of the total energy requirement. The optimization results found the best working condition, which consumes energy of 0.190 GJ/ton CO2, 31 % lower than the basic scenario.

DOI： 10.1016/j.ijggc.2024.104154

High-Throughput CO2 Solubility Measurement in Miscible and Liquid-Liquid Phase Separation Types of Amine Solvent Using Headspace Gas Chromatography Reviewed

Tran, KVB; Yanase, K; Rao, TU; Hirayama, M; Norinaga, K; Machida, H

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH Vol. 63 ( 13 ) page： 5823 - 5832 2024.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Industrial and Engineering Chemistry Research

CO2 solubility is one of the key factors in evaluating not only the efficiency of the absorbent but also the energy consumption of the CO2 capture process from flue gas. In this study, a system namely headspace gas chromatography (HS-GC), which is a combination of gas chromatography (GC-3200, GL Sciences) and a headspace autosampler (Turbomatrix HS16, PerkinElmer), was developed to measure the CO2 solubility of amine solutions. The equilibrium time and calibration curve of this system were checked and compared with those of the literature data. The developed system showed high reproducibility with reference CO2 solubility data of benchmark amine solutions. Distinct from conventional measurement methods of CO2 solubility, high-throughput CO2 solubility measurement by HS-GC shows its advantages such as a small amount sample requirement, rapid achievement of equilibration time, automation of sample exchange, and high reproducibility, which is superior in the amine solvent screening phase. Moreover, this system can evaluate new types of CO2 capture solvents, including the phase separation solvent. By acquiring continuous data, the inflection point in the solubility curve indicated by phase separation was observed. The absorption heat estimated from those CO2 solubility curves measured by this system also agrees well with the experimental data.

DOI： 10.1021/acs.iecr.3c03314

Design and optimization of the flexible poly- generation process for methanol and formic acid from CO2 hydrogenation under uncertain product prices Reviewed

Li, Q; Machida, H; Ren, XS; Feng, ZM; Norinaga, K

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY Vol. 54 page： 635 - 651 2024.2

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Hydrogen Energy

During the design of the carbon capture and hydrogen storage process, a static CO2 hydrogenation poly-generation process for methanol and formic acid synthesis was developed, thereby reducing recycling flow and feedstock losses in the single methanol synthesis process and increasing product diversity. Additionally, a novel flexible poly-generation process was proposed as the product prices fluctuated with the market environment throughout the plant's life cycle. For the static poly-generation process, a mixed integer nonlinear programming model was established, followed by the Mesh Adaptive Direct Search algorithm to determine the optimal parameter design. For flexible processes, with the unscented transform tool, a two-stage optimization strategy is proposed for obtaining optimal design and operating parameters that are computationally tractable. With an input CO2 flow rate of 200 kmol/h, the results show (1) the static process with an optimal Return On Investment of 13.05%, a fixed investment cost of $ 34.14 × 106, and an annual net profit of 4.46 × 106 $/year; and (2) the flexible process, in which the flexibility indices of the methanol and formic acid production units are 1.088 and 1.194, respectively, resulting the fixed investment cost increase to $ 39.19 × 106, an increase of 14.79%. Accordingly, the annual net profit increased by 8.97% to 4.86 × 106 $/year, while the Return On Investment decreased by 4.67%–12.44%. For investment decision-makers, the flexible poly-generation process can achieve higher profits and reduce potential market risks when they have adequate financing.

DOI： 10.1016/j.ijhydene.2023.01.205

Regulation of temperature distribution in fixed bed reactor for CO2 methanation through "CHESS" monolith structure catalyst Reviewed

Zhang, W; Lin, YX; Zhang, YM; Li, TL; Li, JZ; Chen, ZW; Norinaga, K

APPLIED THERMAL ENGINEERING Vol. 236 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Thermal Engineering

CO2 methanation suffers from the problem of temperature runaway phenomenon due to its exothermic nature. To mitigate this issue, optimizing catalyst structure becomes crucial. This work established numerical models to investigate the CO2 methanation reaction and heat/mass transfer process in the reactor with porous pellet and monolithic catalysts. Results show that the reactor with porous pellets has the lowest carbon conversion per unit pressure drop due to its large total pressure drop. In contrast, the reactor with monolith exhibits a much larger carbon conversion per unit pressure drop but a smaller absolute carbon conversion. Based on this, an improved “CHESS” monolith structure was proposed and improved, which not only maintains a high absolute carbon conversion (62.6 %) but also enhances the heat transfer process in CO2 methanation. Moreover, compared with the reactor with porous pellets, the maximum temperature in the improved “CHESS” monolith was decreased by around 11.09 %.

DOI： 10.1016/j.applthermaleng.2023.121826

1-02　Tar and soot formation characteristics of various coals in a two-stage entrained flow coal gasifier revealed by detailed chemical kinetic modeling

LI Tailin, NAKAMURA Maiki, UEHARA Yusuke, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 60 ( 0 ) page： 4 - 5 2023.10

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

Substituting air with either CO2 or H2O in the gasifying agents presents a viable strategy for promptly integrating a carbon-neutral energy vector into coal gasification technology, concurrently mitigating harmful particulate matter emissions. However, fully understanding the evolution of tar in the practical gasifier has proven to be challenging owing to complex mixture of the scale of reactors. This study presents a detailed kinetic investigation of tar and soot formations from the gas-phase reactions in the reductor of a two-stage entrained flow coal gasifier under oxy-fuel (O2/CO2, O2/H2O) atmospheres. The effects of temperature and coal types were studied. The results show that benzene, followed by naphthalene and phenanthrene, serves as the primary tar products. Higher temperature promotes tar reduction, especially under O2/H2O condition. Moreover, soot yield under the O2/H2O condition is less than that under the O2/CO2 condition owing to weaker hydrogen abstraction acetylene addition route. Soot yield decreases with the temperature rises. This work provides valuable insights and guidance for the reduction of tar and soot in the two-stage entrained flow coal gasifier under oxy-fuel atmospheres.

DOI： 10.20550/jiesekitanronbun.60.0_4

1-08　The computational fluid dynamics analysis resolved at the formed catalyst shape level of CO2 hydrogenation reactor Reviewed

SHIMADA Taiki, LIN Yixiong, NAKAMURA Maki, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 60 ( 0 ) page： 16 - 17 2023.10

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

This paper reports a 3D computational fluid dynamics simulation of carbon dioxide (CO2) methanation in a shell-and-tube reactor resolved to the catalyst geometry level. Fluid flow, heat transfer, and mass transfer are calculated, and the local distribution of gas and solid phases in the reactor is shown in detail. To generalize the simulation model, the catalyst effectiveness factor was treated as a variable, and the catalyst effectiveness factor equation and its parameters were investigated. As a result, the catalyst effective coefficient derived from the general Thiele modulus was the best agreement for the present computational model. For higher accuracy, the equations need to be improved to be more suitable for more reality models and chemical reaction equations.

DOI： 10.20550/jiesekitanronbun.60.0_16

CFD simulation of CO2 methanation through the Sabatier reaction in a shell-and-tube reactor incorporating phase change on the shell side Reviewed

Kazui Fukumoto, Wei Zhang, Risa Mizoguchi, Yixiong Lin, Cheolyong Choi, Hiroshi Machida, Koyo Norinaga

Fuel Vol. 349 page： 128126 - 128126 2023.10

Modeling the Chemical Structures of Coals with Different Classifications Using Mean Molecular Weights

Hata Yuki, Hayashizaki Hideyuki, Takanohashi Toshimasa, Takahashi Takafumi, Kanehashi Koji, Norinaga Koyo

Tetsu-to-Hagane Vol. 109 ( 10 ) page： 792 - 801 2023.10

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

The chemical structure models for the extractions and residues of two types of bituminous coals, A and B, were constructed. The molecular weights of the extractions were determined via gel permeation chromatography (GPC). New standard materials with structures similar to those of coal extraction (i.e., 9, 10- diphenylanthracene, 5,6,11,12-tetraphenylnaphthracene, and chemical compounds A (Mw = 811) and B (Mw = 1135), which were synthesized using the coupling reaction) were adopted for GPC in order to obtain more accurate mean molecular weights than those in literature. Furthermore, a support program for constructing chemical structure models based on 1H nuclear magnetic resonance (NMR) spectra was adopted. The coal models constructed suitably indicate the differences between the types of coal. In particular, it is found that a high pyridine-insoluble fraction extracted rate, which accounts for the most significant difference between the total extracted rates for coals A and B, enhance the coking property of coal A. In addition, the cluster size in the magic solvent-insoluble fraction might affect the softening property of coal.

DOI： 10.2355/tetsutohagane.TETSU-2023-042

Facile Synthesis and Insight of Atomically Dispersed Ni Catalyst on N-Doped Carbonized Lignin for Highly Efficient Electrochemical CO2 Reduction to CO Reviewed

Park, GD; Sirisomboonchai, S; Norinaga, K

CHEMSUSCHEM Vol. 16 ( 16 ) page： e202300530 2023.8

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

For the electrochemical CO2 reduction reaction (CO2RR), the single-metal atom catalysts (SACs) on N-doped carbon are considered promising alternatives to conventional catalysts owing to their unique electrocatalytic properties. However, environmentally friendly methods to prepare SACs are still required. Herein, Ni SAC was synthesized using lignin derived from biomass whose structural and chemical properties render it suitable as both a base carbon matrix and a metal chelating agent. The coordination environment of active Ni−Nx sites was readily manipulated by controlling thermal activation. The Ni SAC on lignin-derived N-doped carbon achieved an outstanding CO Faradaic efficiency of 98.2 % at −0.9 V vs. RHE, which is comparable to those of conventional SACs. Experimental results combined with DFT calculations demonstrate the optimal conditions for manufacturing Ni SAC which is highly selective for CO2-to-CO conversion and the effect of the electronic structure of Ni atom on CO2RR kinetics.

DOI： 10.1002/cssc.202300530

6-1-1 Overall electrochemical CO2 reduction - oxygen evolution reaction system via electrodeposition bimetallic covered Cu-foam based electrode Reviewed

SIRISOMBOONCHAI Suchada, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 32 ( 0 ) page： 116 - 117 2023.8

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

CO2 reduction reaction(CO2RR), as a potential path toward converting CO2 to fuel, is of great significance for alleviating the shortage of fossil fuels and combatting global climate change. Cu foam (CF) exhibits high electrochemical water splitting and CO2 reduction activity. Practical electrochemical overall CO2RR−OER two-electrode systems include a CO2RR at the cathode and an oxygen evolution reaction (OER) at the anode. Herein, we emphasized the CF-modified surface for the two-side reaction by constructing earth-abundant materials on the CF-modified surface with InZnCu/CF as the cathode and Cu(OH)2 NWs@NiCo-LDH as the anode. These were efficient for a CO2RR system with a potential close to an ideal thermodynamic potential for an overall CO2RR−OER. Although this system had different metal composites on both sides, this still allowed a sustainable operation for 40 h with high efficiency. Moreover, we emphasized a further development in scalability. Thus, the energy input for the conversion of CO per ton of CO2 resulted in a low range. The demonstration of the CO2RR−OER provided a facile method of fabricating electrodes based on CF and a constructed overall CO2RR system, which will guide the future development of practical industrial applications.

DOI： 10.20550/jietaikaiyoushi.32.0_116

4-4-1 Effect of fluid temperature on heat transfer and flow behavior in a sublimation tank Reviewed

YAMAGUCHI Hiroyasu, UEHARA Yusuke, MACHIDA Hiroshi, NORINAGA Koyo, SAITO Yasuhiro

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 32 ( 0 ) page： 90 - 91 2023.8

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

This study investigated the temperature distribution in a laboratory-scale sublimation tank. Numerical simulations in the sublimation tank which cooled CO2 gas at a cold plate were performed to examine the effect of the inlet and initial temperatures of CO2 gas on the temperature distribution. The results showed that the inlet temperature had a minimal impact on the temperature distribution in the tank due to the low flowrate of the gas. In contrast, a decrease in the initial temperature resulted in the increase of the sublimation region below the sublimation temperature, indicating the possibility of dry ice deposition in areas other than near the cold plate.

DOI： 10.20550/jietaikaiyoushi.32.0_90

4-5-1 Design and Optimization of the Flexible Poly-generation Process for Methanol and Formic Acid from CO2 Hydrogenation Under Uncertain Product Prices☆ Reviewed

LI Qiao, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 32 ( 0 ) page： 98 - 99 2023.8

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

During the design of the carbon capture and hydrogen storage process, a flexible CO2 hydrogenation poly-generation process for methanol and formic acid synthesis was developed to reduce recycling flow and feedstock losses in the single methanol synthesis process and increase product diversity. This poly-generation process is formulated as the MINLP model, which was optimized using a two-stage optimization strategy with the unscented transform tool to obtain optimal design and operating parameters that are computationally tractable. For investment decision-makers, the flexible polygeneration process can achieve higher profits and reduce potential market risks when they have adequate financing.

DOI： 10.20550/jietaikaiyoushi.32.0_98

Insights into structure-performance relationship in radial flow fixed bed reactor for CO2 methanation Reviewed

Zhang, W; Lin, YX; Norinaga, K

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY Vol. 48 ( 64 ) page： 24594 - 24606 2023.7

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Hydrogen Energy

The extraction of petroleum and natural gas is often accompanied by a large number of associated gases, especially the high CO2 content reservoirs facing the emission of a large amount of CO2. CO2 methanation is recognized as one of the suitable candidates for CO2 utilization to reduce the emission of CO2. Because of the highly exothermic nature of the reaction, however, it is very important to enhance the heat transfer process inside the reactor and inhibit the formation of hot spots. In the fixed bed reactor, the heat transfer in the radial direction is greatly limited compared with that in the axial direction. Thus, this work adopted the radial flow reactor to evaluate the CO2 methanation process by the means of a numerical model based on OpenFOAM. Four types of radial flow reactor configurations, namely centrifugal Z-type, centrifugal Π-type, centripetal Z-type, and centripetal Π-type, were compared. The fluid flow, heat transfer, and reaction performances for these reactors were discussed under consistent operating conditions. Results show that the centrifugal Π-type structure has the most uniform flow field. In terms of heat transfer and reaction performance, the centripetal Z-type structure is the best among the four radial flow reactor configurations. These findings provide a theoretical basis and technical guidance for designing and developing radial flow reactors.

DOI： 10.1016/j.ijhydene.2023.03.343

Polycyclic aromatic hydrocarbons (PAHs) and soot formations under different gasifying agents: Detailed chemical kinetic analysis of a two-stage entrained flow coal gasifier Reviewed

Tailin Li, Cheolyong Choi, Kazui Fukomoto, Hiroshi Machida, Koyo Norinaga

Fuel Vol. 343 page： 127876 - 127876 2023.7

Facile pyridinization of bio-based furfural into 3-hydroxypyridines over Raney Fe catalyst Reviewed

Ren, DZ; Jiang, XL; Zhang, NH; Duo, J; Norinaga, K; Huo, ZB

BIOMASS CONVERSION AND BIOREFINERY Vol. 13 ( 9 ) page： 8115 - 8121 2023.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Biomass Conversion and Biorefinery

Production of pyridine derivatives from bio-based feedstocks instead of fossil fuels is a promising strategy. The development of effective heterogeneous catalysts and mild reaction systems for pyridinization of renewable biomass derivatives remains a huge challenge. In this article, a direct and environment-friendly method was reported to produce 3-hydroxypyridine from bio-based furfural in water over a Raney Fe catalyst. Raney Fe exhibited an efficient catalytic performance for activation of the aldehyde group of furfural and afforded an 18.2% yield of 3-hydroxypyridine at 120 °C with ammonia as N source. The polymerization of furfural on the catalyst in hot water was the main cause of deactivation, which was verified by the scanning electron microscope (SEM), X-ray diffraction (XRD), and N2 adsorption and desorption analysis. A possible mechanism for this reaction was also proposed. This study provides a new way for academia and industry to realize the synthesis of nitrogen-containing chemicals from biomass and its derivatives.

DOI： 10.1007/s13399-021-01802-5

CFD simulation of CVD reactors in the CH3SiCl3(MTS)/H2 system using a two-step MTS decomposition and one-step SiC growth models Reviewed Open Access

Ogawa, T; Fukumoto, K; Machida, H; Norinaga, K

HELIYON Vol. 9 ( 4 ) page： e15061 2023.4

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

In this study, we report on a computational fluid dynamics (CFD) simulation of the chemical vapor deposition reactor of silicon carbide (SiC) in the methyltrichlorosilane (MTS, CH3SiCl3)/H2 system. The formation of SiC thin film is controlled by various process parameters, such as temperature and pressure. In this study, we propose a reaction mechanism of MTS decomposition to SiC growth on a substrate surface for CVD reactors in the CH3SiCl3(MTS)/H2 system. The reaction mechanism has two gas-phase pyrolysis reactions and one SiC film formation reaction. However, we individually build and validate MTS decomposition and SiC growth models to reduce uncertainty. An in-house version of reactingFoam, a reactive flow solver within OpenFOAM v2006, was used as the simulation tool. Our model accurately reproduced MTS decomposition for T = 1100–1350 K and [H2]/[MTS] = 2.65–14 at p = 101,325 Pa. Then, the MTS decomposition model was coupled with the SiC growth model, and the coupled model was applied to the SiC deposition data. The model could reproduce multiple datasets through validation studies.

DOI： 10.1016/j.heliyon.2023.e15061

Lattice Boltzmann study on the effect of hierarchical pore structure on fluid flow and coke formation characteristics in open-cell foam for dry reforming of methane Reviewed Open Access

Lin, YX; Yang, C; Zhang, W; Machida, H; Norinaga, K

CHEMICAL ENGINEERING SCIENCE Vol. 268 2023.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Engineering Science

Dry reforming of methane (DRM) is one of the feasible strategies for carbon capture and utilization. However, the DRM process has a high tendency toward carbon deposition, which is restricted to industrial applications. In order to further improve coke formation resistance, open-cell foam with hierarchical pore structure was investigated. An artificial algorithm was adopted to construct a hierarchical pore structure in open-cell foam. Based on a 3-D lattice Boltzmann model, this work explored the effect of two hierarchical pore structure parameters on the fluid flow and coke formation characteristics in open-cell foam, which are hierarchical pore volume ratio (V2/V1) and hierarchical pore size ratio (d2/d1). The results indicated that increasing V2/V1 and d2/d1 can significantly promote permeability. Under the restriction ofV2/V1 = 4, from d2/d1 = 1 to 4, the coke formation rate decreases by approximately 57.49 %. These findings provide a theoretical basis and technical guidance for designing and developing open-cell foam reactors.

DOI： 10.1016/j.ces.2022.118380

Estimation of effective thermal conductivity in open-cell foam with hierarchical pore structure using lattice Boltzmann method Reviewed

Japanese Gasification Technology Reviewed

NODA Reiji, ENOMOTO Hiroshi, NAMIOKA Tomoaki, FUSHIMI Chihiro, HOSOKAI Sou, NORINAGA Koyo

Nihon Enerugii Gakkai Kikanshi Enermix Vol. 102 ( 1 ) page： 74 - 79 2023.1

Lin, YX; Yang, C; Zhang, W; Fukumoto, K; Saito, Y; Machida, H; Norinaga, K

APPLIED THERMAL ENGINEERING Vol. 218 2023.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Thermal Engineering

Effective thermal conductivity in open-cell foam with hierarchical pore structure was estimated using lattice Boltzmann method. A new structure algorithm was proposed to reconstruct hierarchical pore structure in open-cell foam. In order to elucidate the heat transfer characteristics in hierarchical pore structure, the effect of structure parameters, namely the hierarchical pore size ratio (d2/d1), the hierarchical pore volume ratio (V2/V1), and temperature on the effective thermal conductivity was investigated. These results indicated that hierarchical pore structure is unfavorable to the effective thermal conductivity in open-cell foam for the heat conduction process. At high temperatures (Tave = 450–1650 K), however, the effective thermal conductivity in hierarchical pore structure is higher than that in uniform pore structure considering heat radiation. Furthermore, for the heat conduction process, a correlation of the effective thermal conductivity related to open-cell foam with hierarchical pore structure was proposed and validated by available experimental data.

DOI： 10.1016/j.applthermaleng.2022.119314

Boosting in-situ hydrodeoxygenation of fatty acids over a fine and oxygen-vacancy-rich NiAl catalyst br Reviewed Open Access

Wang, JY; Ren, DZ; Zhang, NH; Lang, JY; Du, YY; He, WH; Norinaga, K; Huo, ZB

RENEWABLE ENERGY Vol. 202 page： 952 - 960 2023.1

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

Hydrodeoxygenation (HDO) of fatty acids into long-chain alkanes for aviation fuels with alcohol hydrogen donor at mild condition over Ni-based catalyst is a practicable subject. However, highly active sites design for Ni-based catalyst remains significant challenges. Herein, a fine NiAl particle catalyst with numerous oxygen vacancy sites was fabricated via hydrothermal and reduction treatment. Introduction of small amount of Al species into Ni catalyst not only reduces the Ni particle size exposing plenty of active sites, but also generates oxygen vacancies in AlOx and sets up charge transfer in Ni-AlOx interfaces, thus guarantees the excellent in-situ HDO activity of fatty acids using isopropanol as hydrogen donor. Density functional theory calculation results further reveal that Ni (111) modified by AlOx with oxygen vacancy improves the charge density in Ni-AlOx interface and enhances the adsorption of fatty acid, facilitating the hydrodeoxygenation process. Benefiting from these attributes, Ni–Al0.33Ox presented superior catalytic activity and stability, which achieved 93.2% yield of n-heptadecane at 250 °C and was able to reuse at least 4 times. Therefore, the as-prepared Ni–Al0.33Ox is a promising Ni-based catalyst for alkanes production via in-situ HDO of fatty acids at mild conditions.

DOI： 10.1016/j.renene.2022.11.095

Modeling and estimating kinetic parameters for CO<inf>2</inf> methanation from fixed bed reactor experiments Reviewed

Tsuboi T., Yasuda S., Choi C., Zhang W., Machida H., Norinaga K., Yajima T., Kawajiri Y.

Journal of Advanced Manufacturing and Processing Vol. 5 ( 1 ) 2023.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Advanced Manufacturing and Processing

CO2 methanation, which converts CO2 and hydrogen into methane as fuel, is one of the promising candidates for the development of CO2 utilization technologies. Recently, a highly active catalyst made of Ni/ZrO2 for methanation has been developed, and is currently investigated as a potential use in a high-performance reactor. However, design of reactor must be carried out carefully, since this reaction is highly exothermic, which may cause reactor runaway and deterioration of catalysts. For this problem, a mathematical model that can predict the behavior inside the reactor is necessary. In this work, we consider the methanation reaction of CO2 in a reactor model and estimate the kinetic parameters in the reaction rate model from experimental data. In the parameter estimation using literature values and Tikhonov regularization, eight kinetic parameters in the rate equations were identified from 64 data points with a wide range of conditions. We confirm that molar fractions at the reactor exit predicted by this reactor model are in good agreement with the experimental results. Furthermore, the developed model was validated to predict the compositions and temperature that were not used in the estimation. We expect the developed model will be a powerful tool for the reactor design.

DOI： 10.1002/amp2.10145

Large-eddy simulation of the non-adiabatic reforming process of hot coke oven gas using a flamelet-based approach Open Access

New Data Processing Method for Heavy Oil Components Analyzed by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Reviewed Open Access

KATANO Keita, SUZUKI Teruo, MATSUMOTO Kotaro, KATO Hiroshi, NORINAGA Koyo

Journal of the Japan Petroleum Institute Vol. 66 ( 4 ) page： 101 - 108 2023

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

A data processing method to automatically assign molecular formulae and correct the abundances was developed and used to improve the reliability and quantitative accuracy of data obtained via Fourier transform ion cyclotron resonance mass spectrometry. The technique was utilized to analyze fractions of atmospheric residue, and assigned molecular formulae for each fraction. The algorithm automatically identified nearly 20,000 heavy oil components. The reliability of the data processing technique was demonstrated by absolute mean mass errors in the range of 0.15-0.23 ppm. Distillation simulation was used to correct the abundances of assigned molecular formulae. The distillation properties were estimated from the molecular formulae, and corrections made to match the simulated results within 1 wt%. The correction factor indicated that lower boiling point components tended to require higher correction factors, suggesting that the ion transport efficiency of the instrument becomes lower in the lower molecular weight region.

DOI： 10.1627/jpi.66.101

Changes in Intermolecular Interaction Forces Inducing Glass Transition Determined by Three-Dimensional Aggregated Structural Models of Coal Reviewed Open Access

Hata Yuki, Hayashizaki Hideyuki, Matsuzaki Yoichi, Morimoto Masato, Takanohashi Toshimasa, Takahashi Takafumi, Kanehashi Koji, Norinaga Koyo

ISIJ International Vol. 63 ( 9 ) page： 1433 - 1440 2023

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

The three-dimensional aggregated structural models of two types of coals, A and B, were constructed. It is found that the density and the Tg of the models were qualitatively consistent with values obtained experimentally. The Tg of coals A and B calculated using the model structures are 315°C and 328°C, respectively. The effect of temperature on the distribution of cohesive energy was quantitatively elucidated using the three-dimensional aggregated structural models. The cohesive energy density (CED) of coal B was greater than that of coal A at temperatures <Tg. However, at temperatures >Tg, the CED of coal A is comparable to that of coal B. This implies that the molecules are more strongly aggregated in coal B than in coal A at low temperatures due to hydrogen bonding, and the intermolecular interaction is considered to have gradually relaxed above the Tg. It is concluded that differences in the molecular and cohesive structures of the coals led to differences in the distribution of van der Waals energy and electric energy at different temperatures. The van der Waals energy changed from attraction to repulsion at about 450°C and 285°C in coal A and B, respectively. Electric energy remained an attractive force as the temperature increased. The mechanism of the 13°C difference in the calculated Tg of each coal can be explained by the temperature change in the intermolecular force distribution. Therefore, this three-dimensional aggregated structural model can be used to understand the thermal behavior of aggregated molecules, such as coal thermoplasticity.

DOI： 10.2355/isijinternational.ISIJINT-2022-547

Experimental Study on Quantitative Evaluation of Transferable Hydrogen in Possible Raw Materials for Metallurgical Cokes Including Bituminous, Sub-bituminous, Lignite Coals and Biomass Reviewed Open Access

Zhang Lijuan, Uehara Yusuke, Nakamura Maki, Choi Cheolyong, Liu Chong, Machida Hiroshi, Hayashizaki Hideyuki, Kawai Yuya, Hata Yuki, Norinaga Koyo

ISIJ International Vol. 63 ( 9 ) page： 1441 - 1450 2023

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

Researchers have thoroughly studied coal pyrolysis over a long period, while the analysis of volatile evolution and the chemical structural changes of solid char were carried out individually in most of the studies. In this work, we quantified the chemical reactions to explain the different physical phenomena, such as softening and caking properties, exhibited by different ranks of coals during pyrolysis. Four typical carbonaceous feedstocks (bituminous, sub-bituminous, lignite coals, and biomass) were selected as test samples. The authors analyzed the generated gas during pyrolysis by using a quadrupole mass spectrometer (Q-MS) and the chemical structure of the pyrolyzed char via spectroscopic methods (NMR, FT-IR, CHNS, and XPS) to gain new insights into the pyrolysis mechanism of the carbonaceous feedstocks. Transferable hydrogen was introduced to define the hydrogen used to stable the free radicals formed during pyrolysis, which can be obtained by quantifying the conversion routes of hydrogen. The hydrogen released for the growth of aromatic clusters has three pathways, namely, (1) consumption by the hydrodeoxygenation reaction to produce pyrolytic vapor, (2) release as gaseous H2, and (3) transferable hydrogen. The calculation shows that the amount of transferable hydrogen during pyrolysis decreases as the coal rank gets lower. For pyrolysis up to 500°C, the amount of transferable hydrogen is 3.96, 2.32, and 1.36 mol/kg-coal for bituminous, sub-bituminous, and lignite coals, respectively. On the other hand, the transferable hydrogen of biomass needs to be further considered in terms of the effect of cellulose and hemicellulose’s structure.

DOI： 10.2355/isijinternational.ISIJINT-2022-517

YU Panlong, YADAV Sujeet, HU Yong, KAI Reo, NORINAGA Koyo, KUROSE Ryoichi, WATANABE Hiroaki

Journal of Thermal Science and Technology Vol. 18 ( 2 ) page： 23-00279 - 23-00279 2023

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

Large-eddy simulation (LES) coupling with a non-adiabatic flamelet progress variable (NA-FPV) approach with reconstructed flamelet chemistry states is employed to simulate the hot coke oven gas (HCOG) reforming process. In the NA-FPV model, the chemistry states are first computed based on the correction factor for enthalpy defects and then modified by substituting the species statistics in the maximum heat loss state with those of less heat release to compensate for the unphysical results. The numerical results of LES coupling this NA-FPV model have been compared with the experimental measurement data in terms of temperature and yields, and reasonable agreements have been achieved. According to the LES results, it is seen O2 only participates in the combustion process in the upper stream and the combustion process which mainly consumes H2 and CO is to provide the other reforming process with heat and steam. In the upper and middle streams, the main HCOG jet is wrapped by the swirling high-temperature combustion products, and the reforming process primarily takes place by consuming CH4, polycyclic aromatic hydrocarbons (PAHs), and steam, while considerable H2, CO, and CO2 are produced. It is observed that accompanying the reforming process C2H2 is generated and it peaks in the middle stream, thus it is considered soot is formed in the complex reactions.

DOI： 10.1299/jtst.23-00279

Development of a kinetic model for CO2 methanation over a commercial Ni/SiO2 catalyst in a differential reactor Reviewed

Khuenpetch, A; Choi, C; Reubroycharoen, P; Norinaga, K

ENERGY REPORTS Vol. 8 page： 224 - 233 2022.12

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

Development of a kinetic model for CO2 methanation over a commercial nickel catalyst was performed to consider pathways of CO2 conversion via Sabatier and RWGS reactions. H2/CO2 ratio in the feed gas composition was varied at the stoichiometry of the Sabatier reaction assuming a fictitious CO2 conversion of 0 to 0.7. Non-stochiometric gas feeding and the addition of product gases, i.e., methane and steam, were also considered to examine reaction orders and inhibition effects. The kinetic tests were carried out at 300–350 °C and 0.1–0.9 MPa. GHSV corresponded to 37,494 h−1. The stable activity was achieved by forcibly stressing the catalyst under the equilibria at 500 °C for 35 h. The kinetic measurements were conducted at an isothermal differential fixed bed reactor in the absence of heat and mass transport limitations. The methanation reaction was first fitted with the power law and LH approaches by considering the Sabatier reaction. Then, the RWGS reaction was added to consider CO formation using the power law models. The results showed a better fitting of experimental observations by using the LH expression with the formation of formyl as RDS and the power law model with inhibiting influence of water.

DOI： 10.1016/j.egyr.2022.10.194

1-07 Highly selective electrochemical reduction of CO2 into CO achieved via indium thin-layer on zinc nanosheet over Cu foam Reviewed

SIRISOMBOONCHAI Suchada, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 59 ( 0 ) page： 14 - 15 2022.10

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

Electrochemical reduction (ECR) of CO2 is one of the most promising technologies for electrification of the conversion process of CO2 to obtain valuable chemicals/fuels without extreme condition requirements. Here, the performance of an electrocatalyst with the three-dimensional structure of indium thin-layer dispersed completely over Zn nanosheet structure growing on Cu/Cu foam (CF) is presented. This electrocatalyst was fabricated by electrodeposition of In and Zn over CF and exhibited a superior reduction at a Faradaic efficiency of 93.7% and an excellently long duration of 100h. Furthermore, owing to the synergy of the In thin layer, the Zn nanosheets provided a high active surface area and strong mechanical robustness during the reaction. Moreover, the InZnCu/CF catalyst presented low input energy of 2.90MWh for converting one ton of CO2 into CO, that is an encouraging achievement toward a feasible large scale applications.

DOI： 10.20550/jiesekitanronbun.59.0_14

2-26 Evaluation of lignin conversion into valuable chemicals via hydrogenation combined with fast pyrolysis processes Reviewed

ZHANG Lijuan, SIRISOMBOONCHAI Suchada, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 59 ( 0 ) page： 80 - 81 2022.10

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

Lignin, as an important part of lignocellulosic biomass, should give more attention to promote the utilization of biomass. Being a polymer composed of phenylpropane units, lignin is regarded as a promising candidate for obtaining olefins and aromatic compounds. Herein, thermo-catalytic hydrogenation was used as a pretreatment process of lignin, after that more olefins and aromatics were obtained from the solid hydrogenated lignin via fast pyrolysis. This two-stage valorization process was techno-economically evaluated by Aspen plus and compared with the conventional fast pyrolysis process of lignin. Process simulation based on the experiment data suggested the significant economic benefit of this strategy to convert lignin into valuable chemicals, like olefins, aromatics, and phenolics.

DOI： 10.20550/jiesekitanronbun.59.0_80

2-06 Numerical simulation of polycyclic aromatic hydrocarbons and soot formations from coal volatiles in a Two-stage Entrained Flow Gasifier with detailed chemistry Reviewed

LI Tailin, CHOI Cheolyong, FUKUMOTO Kazui, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 59 ( 0 ) page： 40 - 41 2022.10

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

CO2 recirculation in the oxy-fuel Integrated Coal Gasification Combined Cycle (IGCC) system is essential for continuous use of coal in the future. This study presents a detailed kinetic investigation into coal gasification under O2-N2 and oxy-fuel (O2-H2O, O2-CO2) gasifying agents. The effects on polycyclic aromatic hydrocarbons (PAHs) and soot formation in the reductor of a two-stage entrained flow gasifier were simulated using CHEMKIN. The detailed chemical kinetic model includes 202 species, 1,351 gas-phase reactions, and 101 surface reactions. The numerical results showed that the oxy-fuel blown modes promoted tar reforming to complete elimination at 1,200°C (<1.5mg/Nm3). Because of a different tar conversion behavior, the O2-H2O blown mode provided a more potent tar-yield inhibition. In the case of soot formation, the amount of soot decreased under oxy-fuel blown modes. This behavior resulted from hydrogen abstraction and C2H2 addition (HACA) surface growth, and nucleation rate reductions. Also, the PAHs condensation had a weak effect on the soot formation rate among different gasifying agents. This study promises a better gasification process design for a two-stage entrained flow gasifier in an oxy-IGCC system.

DOI： 10.20550/jiesekitanronbun.59.0_40

Analysis of Low Temperature-oxidation Mechanism for Coal by Using High Resolution Solid State NMR and Gas Analysis Reviewed Open Access

Hata Yuki, Takahashi Takafumi, Sakuragi Kiyoshi, Yamaguchi Akimasa, Saito Koji, Norinaga Koyo

Tetsu-to-Hagane Vol. 108 ( 10 ) page： 693 - 702 2022.10

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

Spontaneous combustion property of low rank coal, an important issue in coal science, has been substantially studied. However, there are few studies discussing quantitative chemical structural changes of coal during its oxidization under 80°C.In the present study, low rank coals of X and Y were oxidized in an adiabatic vessel where their temperature was increased due to spontaneous heating. Generated gases of H2O, CO2, and CO were analyzed by gas chromatography during the oxidization. As a result, coal Y, which was more easily oxidized than coal X, showed higher generation rate of CO2 and CO gas than coal X. Some of H2O generated during the oxidation must have been remained in coal as adsorbed water since the amount of water in the oxidized coal was higher than that before oxidation.13C MAS NMR spectra of coal X and Y indicated that and chemical reaction producing carboxyl acid in coal Y is more activated than that in coal X. Furthermore, the number of aromatic carbon was reduced during the oxidization. It implied that the aromatic carbon might contribute to oxidization reaction. Coal Y before oxidation had smaller number of aromatic carbon per one cluster than coal X, while the structural parameters of aliphatic carbons in coal X and Y were almost the same. It is considered that smaller number of aromatic carbons more destabilize carbon radicals to generate “active” species. Such active carbon radicals are suggested to also react with oxygen in the atmosphere.

DOI： 10.2355/tetsutohagane.TETSU-2022-010

Pretreatment of lignin by electrochemical hydrogenation to enhance the olefins and aromatic products during rapid pyrolysis Reviewed Open Access

Zhang, LJ; Sirisomboonchai, S; Choi, C; Machida, H; Norinaga, K

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS Vol. 166 2022.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Analytical and Applied Pyrolysis

Lignin is one of the most promising biopolymers for producing hydrocarbons and aromatic compounds in nature. Electrochemical conversion of lignin is regarded as an attractive technology for producing various aromatic chemicals which are generally derived from fossil fuels. The author reports an electrochemical approach for hydrogenating alkaline lignin (AL), which uses relatively low-cost Ni foam as a working electrode under alkali electrolyte. The primary factors (such as power input, reactor type, temperature, reaction time, catalysts, and electrode substrates) of electrochemical hydrogenation were used to control the products' yield and features. The redox characteristics of the reaction system were directly compared with the cyclic voltammetry measurement under different parameters. After electrochemical hydrogenation (ECH), rapid pyrolysis was conducted on HAL samples to investigate the influence of electrochemical reactions on lignin. The maximum olefins and aromatics yield from HAL was increased to more than three times AL, accounting for 2.22 wt% and 4.07 wt%, respectively. Then, thermogravimetric analysis (TGA), elemental analysis (EA), Fourier-transform infrared spectroscopy (FTIR), and heteronuclear single quantum coherence (HSQC) NMR were employed to characterize hydrogenated lignin samples (HAL), as well as gas chromatography–mass spectrometry (GC-MS) was conducted to investigate the oil-phase products. This work focused on this electrochemical hydrogenation coupled with rapid pyrolysis process to give a possibility that converting lignin into not only liquid oil products, but solid hydrogenated lignin can be used to produce more olefins and aromatics in rapid pyrolysis, and presented the advantages and disadvantages of this two-stage process finally.

DOI： 10.1016/j.jaap.2022.105625

Efficient CO2 Electrochemical Reduction by a Robust Electrocatalyst Fabricated by Electrodeposition of Indium and Zinc over Copper Foam Reviewed

Sirisomboonchai, S; Machida, H; Tran, KVB; Kawasumi, M; Norinaga, K

ACS APPLIED ENERGY MATERIALS Vol. 5 ( 8 ) page： 9846 - 9857 2022.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ACS Applied Energy Materials

Electrochemical reduction of CO2comprising the CO2reduction reactuib (CO2RR) and oxygen evolution reaction (OER) is one of the most promising technologies for electrification of the chemical process industry. Here, the performance of a electrocatalyst with a three-dimensional structure of InZnCu on Cu foam (CF) is presented. This electrocatalyst was fabricated by electrodeposition of In and Zn over Cu and exhibited a superior reduction of CO2to CO at a Faradaic efficiency of 93.7% at -0.7 V and an excellently long duration of 100 h. Due to the synergy of the thin In layer, the Zn nanosheets provided a high surface-active area and strong mechanical robustness during the reaction. Additionally, a two-electrode system was constructed based on the CF-modified surface, which provided valuable guidelines on the overall CO2RR-OER system for further evolution. Furthermore, due to the facile synthesis, the bimetal-layer double hydroxide (LDH) exhibited high conductivity and high OER performance. Hence, the two-electrode system assembled excellent electrocatalysts for the CO2RR-OER (InZnCu/CF||Cu(OH)2NWs@NiCo-LDH/CF) with high conversions of CO2to CO of 67% and 88% at 2 and 50 mA cm-2, respectively. Notably, the CO2RR-OER system exhibited excellent stability in a 40 h CO2conversion with a constant current density of 2 mA cm-2at an ultralow voltage of 1.59 V. Moreover, the calculation of the energy input converting CO per ton of CO2resulted in a low energy input range for further development in scalability. This overall CO2RR-OER proposes development in electrochemical CO2reduction for industrial applications.

DOI： 10.1021/acsaem.2c01564

Selective hydrogenation of furfural to tetrahydrofurfuryl alcohol in 2-butanol over an equimolar Ni-Cu-Al catalyst prepared by the co-precipitation method Reviewed Open Access

Rao, TU; Suchada, S; Choi, C; Machida, H; Huo, ZB; Norinaga, K

ENERGY CONVERSION AND MANAGEMENT Vol. 265 2022.8

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

In order to upgrade biomass-derived platform chemicals to high value-added chemicals and liquid fuels, it is highly advantageous and desirable to synthesize suitable non-precious bimetallic catalysts that are efficient and versatile in chemical reactions. Equal moles of Ni and Cu were dispersed on varying mole ratios of Al by the co-precipitation method to synthesize Ni-Cu alloy particles to obtain a maximum yield of tetrahydrofurfuryl alcohol (THFA) by the liquid phase hydrogenation of furfural. The nickel species were active for both the furan ring (C=C) and carbonyl group (C=O) of furfural molecule, while Cu species were highly active for only the carbonyl group of furfural molecule. Systematic characterization of the prepared catalysts by XRD, TPR, STEM-EDS, and XPS analysis revealed the formation of highly active Ni-Cu alloys and near-equal Ni/Cu surface contents were achieved for the equimolar catalyst, which showcased a maximum of 98 mol% yield of THFA at 140 °C, 30 bar, 4 h. The reaction pressure and temperature showed a substantial effect on the product yield. The solvent selection also influenced the product selectivity, particularly with 2-butanol, which promoted the reaction with its hydrogen donor capacity and supported the ring hydrogenation of FAL to THFA. Moreover, the reduced Ni1Cu1-Al1 catalyst displayed good recyclability for three runs and an equal activity to that of a fresh catalyst after the regeneration.

DOI： 10.1016/j.enconman.2022.115736

Understanding the involved chemistry and physics toward numerically simulating the reactors for carbon resources and carbon dioxide conversions Reviewed

NORINAGA Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 31 ( 0 ) page： xviii - xix 2022.7

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

The recent approaches by the author and co-workers in understanding the involved chemistry and physics toward numerically simulating the chemical reactors are presented. The processes will include the gasification of solid fuels, coal tar reforming, and Sabatier reaction for producing carbon neutral synthetic methane.

DOI： 10.20550/jietaikaiyoushi.31.0_xviii

CFD simulation of the Sabatier process in a shell-and-tube reactor under local thermal non-equilibrium conditions: Parameter sensitivity and reaction mechanism analysis Reviewed Open Access

Lin, YX; Zhang, W; Machida, H; Norinaga, K

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY Vol. 47 ( 34 ) page： 15254 - 15269 2022.4

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Hydrogen Energy

The Sabatier process is a competitive technology applied for carbon capture and utilization. This process increases the risk of carbon deposition and catalyst thermal degradation because of its exothermic property. In this study, a CFD model verified through existing experimental data was established to systematically investigate the Sabatier process in a shell-and-tube reactor. The effects arising from several operating parameters (e.g., gas flow rate, feed gas composition, the thermal conductivity of catalyst pellet, the inlet temperature of cooling phase, as well as phase change refrigeration) on temperature profile and reaction performance were studied. Moreover, a mechanism of three reactions was investigated, including CO2 methanation, CO methanation, as well as RWGS reaction. Furthermore, the competition between CO2 methanation and RWGS reaction was explored. According to the further sensitivity analysis, increasing the thermal conductivity of the catalyst particles would be effective to inhibit hot spots, while keeping the carbon conversion rate unchanged.

DOI： 10.1016/j.ijhydene.2022.03.029

Catalytic transfer hydrogenation of ethyl levulinate into γ-valerolactone over air-stable skeletal cobalt catalyst Reviewed

Ren, DZ; Zhao, C; Zhang, NH; Norinaga, K; Zeng, X; Huo, ZB

JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING Vol. 10 ( 2 ) 2022.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Environmental Chemical Engineering

A fast and easy handled batch air diffusion method (BA) was developed to obtain a non-pyrophoric, air-stable skeletal Co catalyst (A-SCo) for catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) into γ-valerolactone (GVL). A batch air diffusion method (BA) consumed the active adsorbed H2 on the surface of skeletal Co (SCo) but maintained structure catalyst and avoided excessive oxidation of metallic Co, Ni and Al. The 96% yield of GVL was obtained over the A-SCo and HZSM-5 at 140 °C. Further study of CTH process shows that metallic state of A-SCo provides important active sites for dehydrogenation of i-PrOH, which is critical step for hydrogenation of EL. This study provides a simple, efficient method to prepare an air-stable skeletal metal catalyst for CTH and hydrogenation process.

DOI： 10.1016/j.jece.2022.107188

A review of thermal catalytic and electrochemical hydrogenation approaches for converting biomass-derived compounds to high-value chemicals and fuels Reviewed Open Access

Zhang, LJ; Rao, TU; Wang, JY; Ren, DZ; Sirisommboonchai, S; Choi, C; Machida, H; Huo, ZB; Norinaga, K

FUEL PROCESSING TECHNOLOGY Vol. 226 2022.2

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

Major global issues such as greenhouse gas emissions and the excessive use of fossil fuels lead to looking for sustainable and clean energy resources. Lignocellulosic biomass is a prospective resource for sustainable carbon-based energy. The production of petroleum-based green fuels, chemicals, and solvents from biomass-derived products has garnered much attention in the recent past. The study of biomass derivatives hydrogenation improves the efficiency of generating high-value chemicals and provides much-needed insights into the primary reaction mechanism for the effective utilization of raw constituents or biomass. However, the existing thermochemical conversions of biomass and biomass-derived products such as thermal catalytic hydrogenation (TCH) involve energy-intensive and expensive processes. In this regard, sustainable energy generation attracts alternative conversion technologies, including electrochemical conversion (ECC), electrocatalytic hydrogenation (ECH), and photocatalytic conversions that can be directly integrated with renewable wind/solar technologies and operated at ambient or lower temperatures. The role of electrocatalyst and electrolyte is pivotal to achieve efficient and selective ECH of biomass organics. This review paper summarizes the utilization of TCH and ECH processes on cellulose/hemicellulose, lignin, and their derivatives/model compounds, including catalyst types, reaction conditions, hydrogenation efficiency, and technical limitations. The advantages and disadvantages of the two technologies for biomass utilization have also been compared, which provides a more favourable knowledge base and theoretical basis for the subsequent research work.

DOI： 10.1016/j.fuproc.2021.107097

Durability and fire-hazardous-risk evaluation of unique phase separation solvent using high-boiling-point amine and ether Reviewed

Maeda, N; Kishimoto, A; Machida, H; Yamaguchi, T; Yanase, K; Norinaga, K

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol. 114 2022.2

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Greenhouse Gas Control

Durability and fire hazard risk evaluations were conducted to determine the process feasibility of a unique phase separation solvent with a low regeneration temperature (90 °C) consisting of an amine, ether, and a small amount of water. The results are as follows. I) The amine degradation rate of the phase separation solvent was determined to be less than 1/10 of that of monoethanolamine, which was attributed to the high oxidative resistance and low regeneration temperature of the former. II) The composition of the gas that formed in the absorber was completely out of the combustible range during the treatment of 6% oxygen-containing gas on a dry basis. Therefore, we believe that this phase separation solvent is applicable to the treatment of exhaust gas from coal-fired thermal power plants and can realize stable operation with a small amount of amine required for replenishment.

DOI： 10.1016/j.ijggc.2021.103532

Fluctuation in diethylene glycol diethyl ether/water mixtures near the lower critical solution temperature studied by small- and wide-angle x-ray scattering and thermodynamic calculation Reviewed Open Access

Yanase, K; Tran, KVB; Yamaguchi, T; Machida, H; Norinaga, K

JOURNAL OF MOLECULAR LIQUIDS Vol. 346 2022.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Molecular Liquids

We studied local structure of diethylene glycol diethyl ether (DEGDEE)-water mixtures near the lower critical solution temperature (LCST) by means of simultaneous small- and wide-angle x-ray scattering measurement and thermodynamic calculation based on the activity coefficient model. Long-wavelength limits of structure factors SNN(0), SCC(0), and SNC(0), which respectively represent mean square fluctuations in the particle number, the concentration, and their cross correlation, are determined from scattering intensity extrapolated to the zero scattering vector and thermodynamic quantities according to the Bhatia and Thornton formula. SNN(0) and SCC(0) exhibit maxima near critical concentration. We found that difference between partial molar volumes of water and DEGDEE essentially results in SNN(0) values being one order of magnitude larger than SCC(0) values. Further, we determined Kirkwood-Buff (KB) integrals to clarify a mixing state of the solution from a mesoscopic point of view. The KB integrals also exhibit extrema near critical concentration. These results demonstrate self-segregations of both DEGDEE and water in a nanometer length scale even at homogeneous solution states, which can be regarded as a precursor of the macroscopic phase separation. Concentration dependence of the wide-angle scattering curve suggests that the short-range structure, whose length scale is sub-nanometer, moderately changes between the intrinsic bulk structures of DEGDEE and water. Comparison of the KB integrals with those determined by the activity coefficient model using non-random two-liquid equation is presented and effects of the fluctuation on the phase behavior are discussed.

DOI： 10.1016/j.molliq.2021.117830

Determination of Kinetic Parameters for CO2 Methanation (Sabatier Reaction) over Ni/ZrO2 at a Stoichiometric Feed-Gas Composition under Elevated Pressure Reviewed

Modeling the Chemical Structures of Coals with Different Classifications Using Mean Molecular Weights Reviewed Open Access

Hata Yuki, Hayashizaki Hideyuki, Takanohashi Toshimasa, Takahashi Takafumi, Kanehashi Koji, Norinaga Koyo

ISIJ International Vol. 62 ( 5 ) page： 948 - 956 2022

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

The chemical structure models for the extractions and residues of two types of bituminous coals, A and B, were constructed. The molecular weights of the extractions were determined via gel permeation chromatography (GPC). New standard materials with structures similar to those of coal extraction (i.e., 9, 10- diphenylanthracene, 5,6,11,12-tetraphenylnaphthracene, and chemical compounds A (Mw = 811) and B (Mw = 1135), which were synthesized using the coupling reaction) were adopted for GPC in order to obtain more accurate mean molecular weights than those in literature. Furthermore, a support program for constructing chemical structure models based on 1H nuclear magnetic resonance (NMR) spectra was adopted. The coal models constructed suitably indicate the differences between the types of coal. In particular, it is found that a high pyridine-insoluble fraction extracted rate, which accounts for the most significant difference between the total extracted rates for coals A and B, enhance the coking property of coal A. In addition, the cluster size in the magic solvent-insoluble fraction might affect the softening property of coal.

DOI： 10.2355/isijinternational.ISIJINT-2021-459

Choi, C; Khuenpetch, A; Zhang, W; Yasuda, S; Lin, YX; Machida, H; Takano, H; Izumiya, K; Kawajiri, Y; Norinaga, K

ENERGY & FUELS Vol. 35 ( 24 ) page： 20216 - 20223 2021.12

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

Methanation of CO2 using H2 obtained by renewable energy sources has been gaining attention as one of the promising options for utilizing captured CO2 and surplus power obtained when intermittent power sources such as solar and wind energy are used. Herein, kinetics of CO2 methanation over Ni/ZrO2 was studied using a tubular quartz reactor at 0.9 MPa. The Sabatier reaction (CO2 + 4H2 = CH4 + 2H2O, ΔHr298K = – 165 kJ mol–1) was carried out under stoichiometric gas feeding (CO2/H2 = 1/4 v/v to CH4/H2O = 1/2 v/v), and its reaction rate was determined. The exothermic nature of CO2 methanation and extremely high catalytic activities increased the reaction temperature to 400–600 °C even when the feed-gas temperature was as low as 250–400 °C, and the gas hourly space velocity was as high as 3 × 106 h–1. Nonlinear regression analyses based on one- and multistep kinetic models were used to investigate the reaction rates to estimate the kinetic parameters. Both models with optimized parameters can reproduce the experimentally obtained CH4 formation rates for the entire range of the feed-gas conversion with a coefficient of determination (R2) of over 0.98.

DOI： 10.1021/acs.energyfuels.1c01534

An Alternative CO2 Capture with a Pressure Swing Amine Process Driven by Cryogenic Pumping with the Unused Cold Energy of Liquefied Natural Gas Reviewed

Machida, H; Hashiride, R; Niinomi, R; Yanase, K; Hirayama, M; Umeda, Y; Norinaga, K

ACS SUSTAINABLE CHEMISTRY & ENGINEERING Vol. 9 ( 47 ) page： 15908 - 15914 2021.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Sustainable Chemistry and Engineering

This paper presents an alternative concept of CO2 capture that can substantially reduce the energy required for CO2 capture by utilizing unused cold energy. The heat of vaporization of liquefied natural gas (LNG), of which the boiling point is 110 K, is a possible candidate for unused cold energy. This technology is based on a pressure swing amine process combined with a sublimation tank to cool CO2 released from a desorber into dry ice by exchanging the LNG cold energy. The feature of this technology is that pure CO2 is recovered mostly by a pressure swing that decreases the pressure in the desorber utilizing a cryogenic pump with CO2 sublimation instead of a mechanical pump. We developed an amine-based absorbent that can realize the proposed process for exhaust gas from a fossil fuel-fired power plant. A process simulation indicated that the required energy is as low as 0.25 GJ/ton CO2 when both the absorber and the desorber are operated at around 313 K, the desorber pressure is reduced to 1 kPa, and the sublimation tank is operated at 150 K.

DOI： 10.1021/acssuschemeng.1c05892

The effects of nitrogen functional groups and narrow micropore sizes on CO2 adsorption onto N-doped biomass-based porous carbon under different pressure Reviewed

Luo, JY; Liu, BG; Shi, R; Guo, Y; Feng, QG; Liu, Z; Li, LQ; Norinaga, K

MICROPOROUS AND MESOPOROUS MATERIALS Vol. 327 2021.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Microporous and Mesoporous Materials

The biomass-derived N-doped porous carbons have been proved promising adsorbent material, due to their good CO2/N2 selectivity and excellent CO2 adsorption performance. However, many researchers simply studied the effect of nitrogen groups or narrow micropores (less than 0.7 nm) on CO2 uptake at 1 bar and ignored the role of different pressures. In this study, a promising porous carbon derived from eucalyptus bark with high CO2 adsorption capacity was prepared by urea-assisted hydrothermal and KOH activation. The obtained porous carbons were found to be mainly microporous and showed rich nitrogen content. Among the materials, at 1 bar, NPC700 exhibits high CO2 adsorption of 4.20 mmol/g and 6.98 mmol/g at 25 °C and 0 °C, respectively. Based on Grand canonical Monte Carlo (GCMC) simulation, the adsorption density and adsorption energy on graphite slit pore with different pore sizes (0.6–2.0 nm) and N-doped functional groups (pyridinic-N, pyrrole-N and graphitic-N) were calculated. And the results showed that the nitrogen functional groups played a crucial contribution on CO2 adsorption capacity at relative low pressure (0–0.16 bar). In the case of relative high pressure (0.16–1 bar), the narrow micropores volume determined the CO2 uptake capacity.

DOI： 10.1016/j.micromeso.2021.111404

Inhibition of temperature runaway phenomenon in the Sabatier process using bed dilution structure: LBM-DEM simulation Reviewed

Lin, YX; Yang, C; Choi, C; Zhang, W; Fukumoto, K; Machida, H; Norinaga, K

AICHE JOURNAL Vol. 67 ( 10 ) 2021.10

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

The Sabatier process is promising for carbon dioxide utilization and energy storage. However, the serious problem that limits more comprehensive industrial applications is catalyst deactivation due to the temperature runaway phenomenon. The inert particle dilution approach, including the mixing dilution method and layered dilution method is applied to solve this problem. Based on the lattice kinetic scheme-lattice Boltzmann method (LKS-LBM), the effects of three parameters in bed dilution structure reconstructed by the discrete element method (DEM) on temperature distribution and carbon conversion rate were discussed, so as to investigate the relationship between packing structure and temperature distribution. Furthermore, numerical results indicated that an optimal bed dilution structure, which not only can control the peak temperature below the critical temperature to avoid coking and sintering of catalyst, but also can improve the conversion rate by almost 18% compared with the structure without dilution under the same circumstance.

DOI： 10.1002/aic.17304

Comprehensive Compositional Analysis of Heavy Oil Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and a New Data Analysis Protocol Reviewed

Katano, K; Teratani, S; Suzuki, T; Tanaka, R; Kato, H; Norinaga, K

ENERGY & FUELS Vol. 35 ( 17 ) page： 13687 - 13699 2021.9

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

A sequential method that deterministically estimates the molecular composition of heavy oil is reported. A sample of vacuum residua is preseparated into seven fractions: saturated (Sa), aromatic fractions containing one, two, and three or more rings (1A, 2A, and 3A+, respectively), polar and polyaromatic (Po and PA, respectively) resins, and asphaltene (As). The analysis by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) uses one of three different ionization methods depending on the type of structure. Paraffinic species in Sa are ionized by Ag cationization and laser desorption. Aromatic species in 1A, 2A, 3A+, and Po are ionized by atmospheric pressure photoionization. Poorly volatile and condensed aromatic species in PA and As are ionized by laser desorption ionization. Collision-induced dissociation (CID) is used by the FT-ICR MS instrument to determine the structural building blocks. A new data analysis protocol developed to represent petroleum molecules named the composition and structure analyzer (CSA) requires data obtained before and after CID as inputs. The CSA provides juxtaposed attributes for chemical-structure description (JACDs). Structural information based on JACDs can be used to predict physical and chemical properties such as boiling and melting points and solubility parameters and build attribute-based reaction models, to optimize heavy oil upgrading processes.

DOI： 10.1021/acs.energyfuels.1c01429

Density and Viscosity Calculation of a Quaternary System of Amine Absorbents before and after Carbon Dioxide Absorption Reviewed

Tran, KVB; Sato, M; Yanase, K; Yamaguchi, T; Machida, H; Norinaga, K

JOURNAL OF CHEMICAL AND ENGINEERING DATA Vol. 66 ( 8 ) page： 3057 - 3071 2021.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Chemical and Engineering Data

Viscosity and density of amine absorbents affect directly their flow, which is involved in the process design and simulation of carbon dioxide capture. A mixture of 2-(ethyl amino) ethanol (EAE), diethylene glycol diethyl ether (DEGDEE), and water changes its phase from homogeneous to two-liquid ones on CO2 absorption. It is difficult to calculate the viscosity and density of this phase separation solution, especially those of quaternary-component phases. In this research, models to calculate the density and viscosity of the quaternary-component system of EAE/DEGDEE/water/carbamate were suggested based on nonrandom two-liquid (NRTL)-DVOL and NRTL-DVIS models. Given the component concentrations, these models can replicate well the viscosity and density of the solutions. A good calculation result with a few numbers of parameters makes the models simple and easy to use.

DOI： 10.1021/acs.jced.1c00195

Production of light hydrocarbons from organosolv lignin through catalytic hydrogenation and subsequent fast pyrolysis Reviewed Open Access

Zhang, LJ; Choi, C; Machida, H; Norinaga, K

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS Vol. 156 2021.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Analytical and Applied Pyrolysis

Valorization and utilization of lignin have been drawing increasing attention recently. Hydroprocess is one of the main technologies, which can reduce organic compounds and partially depolymerize the macromolecular structure of lignin. The mechanism of lignin hydroprocess has been extensively discussed focusing on hydrogenolysis. In contrast, the solid residue regarded as unreacted or depolymerized lignin has drawn less attention so far. This study proposes an integrated process that consists of catalytic hydrogenation and subsequent fast pyrolysis for valorizing lignin. The results showed that 48−87 wt.% of solid product could be recovered as hydrogenated lignin (H-EOL) after hydrogenation at 200–250 ℃ for 1−7 h. Chemical structure of H-EOL was comprehensively investigated by means of elemental analysis, FTIR, 13C & 1H NMR, and TGA. Furthermore, behavior of fast pyrolysis of H-EOL was detected here for the first time. H-EOL has higher hydrogen to carbon atomic effective ratio(H/Ceff ratio) and achieves the increasing reactivity of thermal decomposition. H-EOL yields light olefins double as much as raw ethanol organosolv lignin (EOL). And the formation of alkanes (C1-C4), benzene, and toluene was promoted to various degrees, while the yield of carbon monoxide, carbon dioxide, and vapor decreased. A novel and efficient pretreatment method has been provided to valorize lignin, which is instructive for subsequent research.

DOI： 10.1016/j.jaap.2021.105096

An Approach to Simulate Vapor Phase Reactions of Coal Volatiles in a Reducing Section of the Two Stage Entrained Flow Gasifier with a Detailed Chemical Kinetic Model

Choi Cheolyong, Adachi Nozomi, Zhang Wei, Machida Hiroshi, Hayashi Jun-ichiro, Watanabe Hiroaki, Norinaga Koyo

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN Vol. 54 ( 6 ) page： 334 - 343 2021.6

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

The present study further develops an approach in predicting reactions undergone by coal volatiles in a reducing section (reductor) of an air-blown two-stage entrained flow gasifier toward designing a better gasification process. A detailed chemical kinetic model was first applied to simulate chemical reactions of a complex molecular mixture of the coal volatiles evolved due to rapid pyrolysis of coal fed into the reductor. The composition of volatiles was determined based on pyrolysis-gas chromatography experiments, where 22 compounds including inorganic gases (H2, H2O, CO and CO2), light hydrocarbon gases (C1–C4) and aromatic hydrocarbons (benzene to pyrene) were identified. Gas composition at the reductor inlet was estimated by integrating the information on the experimentally obtained molecular composition of the volatiles, and the thermodynamically calculated composition of inorganic gases generated from the combustor and the coal feeding rates into reductor and combustor. Concentration profiles of the individual chemical species, as well as soot particles along with the flow direction of the reductor, were revealed by using an extended detailed chemical kinetic model involving 202 species, 1,351 gas-phase reactions and 101 surface reactions for soot formation and growth. The simulation highlighted that near-complete decomposition of tar (<1.5 mg/Nm3) regarded as a set of all aromatic hydrocarbons is likely to require operation temperature of the reductor at temperatures as high as 1,200°C, when the combustor is operated at 1,800°C.

DOI： 10.1252/jcej.20we171

A Review on Detailed Kinetic Modeling and Computational Fluid Dynamics of Thermochemical Processes of Solid Fuels Reviewed

Choi, C; Zhang, W; Fukumoto, K; Machida, H; Norinaga, K

ENERGY & FUELS Vol. 35 ( 7 ) page： 5479 - 5494 2021.4

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

This review presents the recent advances in computational approaches to understand thermochemical reactions of solid fuels with minimized empirical factors. It includes studies on kinetic modeling of gas-phase reactions of multicomponent molecular mixtures of volatiles derived from primary pyrolysis of solid fuels using a database for elementary reactions. Mechanistic studies to model the devolatilization of biomass and coal upon heating are also mentioned. The efforts to integrate the kinetic model with computational fluid dynamics to understand the flow and heat transfer behavior of industrial reactors for solid fuel conversions, including gasification and combustion, are reviewed. These advances are primarily based on the conventional forward analysis that provides a deeper understanding of chemically reacting flows of fuels undergoing thermochemical reactions. For the further development of the thermochemical conversion technology, it can be expected to develop alternative approaches such as inverse analysis to determine the optimal reactor design and operating conditions.

DOI： 10.1021/acs.energyfuels.0c04052

Durability and fire-hazardous-risk evaluation of unique phase separation solvent using high-boiling amine and ether Reviewed

Catalytic hydrotreatment of alkaline lignin and its consequent influences on fast pyrolysis Reviewed Open Access

Zhang, LJ; Choi, C; Machida, H; Huo, ZB; Norinaga, K

CARBON RESOURCES CONVERSION Vol. 4 page： 219 - 229 2021

Authorship：Last author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Carbon Resources Conversion

The current state of lignin has been characterized by these three: (1) as one of the main components in lignocellulosic biomass with an abundant amount; (2) not be taken seriously but treated as a waste product; (3) underutilized due to a complex and stubborn structure. However, lignin can be a rich source for hydrocarbons and aromatic compounds when gives appropriate utilization. In this work, we have studied the hydrotreatment of alkaline lignin (AL) under relatively mild conditions and further investigated the characterization of hydrogenated lignin (HL), especially the behavior during fast pyrolysis. The recovery of the HL decreased with increasing reaction temperature from 60 wt.% to 41 wt.% in the range of 150–250 ℃. The hydrotreated products were analyzed using Elemental Analysis, FTIR (for HL) and GC–MS (for bio-oil). The HL samples were found to have a higher hydrogen/carbon atomic effective ratio (H/Ceff ratio) and a higher degree of saturation than AL. Compared to the internal structure of the lignin before and after hydrotreatment, the side chain groups were removed from AL during the process. After that, from the fast pyrolysis of HL, it was observed that more light hydrocarbons and aromatic compounds were formed than that of AL. Furthermore, fast pyrolysis in the hydrogen atmosphere revealed that more volatile fractions were released compared to the Helium atmosphere. The total olefins yield was increased for HL compared AL from 1.02 wt.% to 3.1 wt.% at 250 ℃ for 7 hours. This study of HL is instructive to some extent for the industrial utilization of lignin.

DOI： 10.1016/j.crcon.2021.09.001

A comprehensive study on butanolysis of furfuryl alcohol to butyl levulinate using tungstated zirconia and sulfonated carbon catalysts Reviewed Open Access

Thuppati, UR; Choi, C; Machida, H; Norinaga, K

CARBON RESOURCES CONVERSION Vol. 4 page： 111 - 121 2021

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Carbon Resources Conversion

This work presents the formation of butyl levulinate, a potential fuel additive, and an excellent renewable chemical obtained by the butanolysis of furfuryl alcohol (FAL) over a solid acid catalyst. The butanolysis of furfuryl alcohol reaction is a strong function of acidity for which tungstated zirconia (WO3-ZrO2), a robust solid acid catalyst, and a sulfonated carbon catalyst were employed to produce high yields of butyl levulinate targeting a lower initial molar ratio of butanol to FAL. A maximum of 28 mol% yield of butyl levulinate was obtained with tungstated zirconia catalyst. Easily prepared sulfonated carbon catalyst at high reaction temperatures facilitated the complete conversion of reaction intermediate, 2-butoxymethylfuran (2-BMF) through which butyl levulinate was formed, and as high as 80 mol% of butyl levulinate yield was produced at an initial mole ratio of 8.5:1 of butanol to FAL. The better results of sulfonated carbon catalyst could be attributed to the presence of -SO3H, carboxylic acid, and phenolic OH groups on the carbon surface.

DOI： 10.1016/j.crcon.2021.03.003

Maeda N., Kishimoto A., Machida H., Yamaguchi T., Yanase K., Norinaga K.

15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021 2021

Language：English Publishing type：Research paper (scientific journal) Publisher：15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021

Durability and fire hazard risk evaluation were conducted to determine the process feasibility on the unique phase separation solvent with low regeneration temperature (90 °C), consisting of amine, ether, and small amount of water. The results we obtained are as follows; I) The amine degradation rate of the phase separation solvent would be less than 1/10 of that of monoethanolamine (MEA), which was contributed by its high oxidative resistant nature and low regeneration temperature. II) The gas composition formed in the absorber was completely out of combustible range and almost no accumulations of explosive compounds such as peroxides were observed when in contact with 6 % oxygen containing gas (dry base). Therefore, we believe that the phase separation solvent is applicable to the treatment of exhaust gas from coal-fired thermal power plants.

Energy analysis of CO<inf>2</inf> separation process with low energy consumption using phase separation solvent Reviewed

Maeda N., Nakanishi K., Kishimoto A., Machida H., Yamaguchi T., Norinaga K.

15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021 2021

Language：English Publishing type：Research paper (scientific journal) Publisher：15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021

We calculated the energy required for regeneration when the phase separation solvent solvent is applied to the treatment of exhaust gas from coal-fired power plants. This solvent is characterized by regeneration at a low temperature of less than 100°C. As a result, it was clarified that under ideal conditions with no pressure drop and no heat loss, the required energy could be suppressed to 1.5 GJ/ton-CO2 by satisfying the following conditions; i) pinch point of the heat exchanger between rich-amine and lean-amine: 1 °C, ii) water concentration of the solvent: kept at 10 wt%, iii) COP of the heat pump: 5.5. However, increase of the pinch point, increase of the water concentration, and decrease of the COP will all result in a significant increase in the required energy. Therefore, in order to realize a process with low energy consumption, it is essential to meet these design constraints.

2-14 Investigation of methanation kinetic model by analysis considering distributions of temperature and gas composition over a catalyst bed Reviewed

CHOI Cheolyong, YASUDA Shoya, ZHANG Wei, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 57 ( 0 ) page： 44 - 45 2020.10

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

CO2 methanation is expected to be an option for energy storage and supply integrated with water electrolysis using renewable energies, named power-to-gas, taking advantages of the applicability to the existing infrastructures for natural gas. There are only a few industrial-scale plants, and development of a kinetic model is essential for scaling up the methanation reactor. In this study, a kinetic model was developed for CO2 methanation under three pressure conditions considered in industrial-scale plants. The rate coefficients were determined at each pressure and correlated with the total pressure. The derived model was applied to an estimation of a larger bench-scale reactor filled with a pelletized catalyst through one-dimensional packed bed simulations, in which the diffusion resistance caused by the use of the pellet was considered using a catalyst effectiveness factor. The kinetic model was able to reproduce the CO2 conversion at the exit and the temperature distribution in the catalyst bed. It revealed that formation of a side product, CO was suppressed at the entire range of reactor.

DOI： 10.20550/jiesekitanronbun.57.0_44

2-16 Development of Phase Separation Solvent and H2 Stripping Process to Save Energy of CO2 Capture Reviewed

MACHIDA Hiroshi, HASHIRIDE Ryusei, SUZUKI Takefusa, NISHIO Hitoshi, YANASE Keiichi, Tran Khuyen, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 57 ( 0 ) page： 48 - 49 2020.10

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

To develop the energy-saving CO2 capture from exhaust gas, we have been studying on both absorbent and process. As an absorbent, we have developed a phase separation solvent that separates into two liquid phases during CO2 absorption, and as a process, we have developed a H2 stripping that supplies H2 to the desorber. We will report the results of case studies with our developed solvents and processes.

DOI： 10.20550/jiesekitanronbun.57.0_48

Online composition analysis of phase separation solvent for carbon dioxide capture using ATR-FT-IR Reviewed

Sato M., Tran K.V.B., Yamaguchi T., Machida H., Norinaga K.

Journal of Advanced Manufacturing and Processing Vol. 2 ( 4 ) 2020.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Advanced Manufacturing and Processing

An amine solvent that undergoes phase change after absorption of CO2 has been studied to reduce the energy consumed during the CO2 capture process. Depending on the components of the solvent, the CO2-rich phase can be separated for the regeneration step or the component in CO2-lean phase accelerates the regeneration step in the solvent that undergoes liquid-liquid phase change. Since the homogeneous solvent separates into two liquid phases after CO2 absorption, an analysis method to track the change in chemical species during the absorption process, especially at the phase separation time, is necessary to illuminate the phenomenon. To establish an online method to analyze the components of the solvent, a Fourier-transform infrared (FT-IR) spectrometer equipped with an attenuated total reflection (ATR) probe was used during the CO2 absorption of phase separation solvent composed of amine, ether, and water. The calibration samples of amines, ethers, and CO2-loaded solutions were used to develop the partial least square regression model. The consumption of reactants, as well as the formation of products, can be monitored quantitatively using the FT-IR spectra. Utilizing this information, the changes in the chemical species shed light on the phase separation mechanism of this solvent: ether was pushed out of the solvent to form a CO2-lean phase due to its hydrophobicity, while CO2 and its products along with amine and water remain in the CO2-rich phase. Without sampling, this rapid and high-accuracy method is suitable for closed processes, especially for a high-pressure process.

DOI： 10.1002/amp2.10067

Rate of CO<inf>2</inf> absorption of a phase-separation absorbent Reviewed

Esaki T., Machida H., Norinaga K.

Journal of Advanced Manufacturing and Processing Vol. 2 ( 1 ) 2020.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Advanced Manufacturing and Processing

In this study, we evaluated the CO2 absorption characteristics of a phase-separation amine absorbent. The phase-separation absorbent consists of a 30:60:10 (by weight percent) mixture of 2-(ethylamino)ethanol, diethylene glycol diethyl ether, and water. The CO2 absorption rate of the phase-separation absorbent was measured in a lab-scale counter flow absorber. In addition, the CO2 transport phenomena in the absorber were analyzed by performing model fitting. The experimental results revealed that the CO2 absorption rates are different before and after phase separation. In fact, the overall CO2 absorption capacity coefficient after phase separation is 4.5 times higher than that obtained before phase separation. By changing the gas-liquid ratio, we obtained a CO2 recovery ratio of over 80% using the model. Thus, the absorption temperature, CO2 loading, and gas-liquid ratio can be tuned to obtain the desired CO2 recovery ratio.

DOI： 10.1002/amp2.10033

1-12 Numerical simulation for a CO2 methanation reactor Reviewed

Zhang Wei, Mizoguchi Risa, Machida Hiroshi, Norinaga Koyo

Proceedings of Conference on Coal Science Vol. 56 ( 0 ) page： 24 - 25 2019.10

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

This paper reports a numerical study for a singl e shell and tube rea ctor of CO2 methanation with a 1.5 m long reaction zone. A new conjugate heat transfer solver is developed based on the open-source OpenFOAM code. The newly developed solver solves the heat transfer problem as well as the reactions happen in the gas phase. The reactor is meshed with fully resolved gas, solid, and coolant regions , Two-temperature model is considered to solve the temperature of catalyst bed . The tube diam e ter is changed to investi gate the effect on the hot spot formation. The results show that the diameter of the tube is an important factor in determining the tem perature profiles of the catalyst bed as well as reacting gas. The peak t emperature of the hot spot was decreased from 980 to 770K with decreasing the tube diame ter from 32 to 14mm at a GHSV=3428h-1.

DOI： 10.20550/jiesekitanronbun.56.0_24

2-5 Numerical simulation of PAH reforming and soot formation in a two-stage entrained flow coal gasifier through a detailed chemical kinetic model Reviewed

CHOI Cheolyong, ADACHI Nozomi, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 56 ( 0 ) page： 56 - 57 2019.10

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

Tar evolved from coal pyrolysis contains polycyclic aromatic hydrocarbons (PAHs) that grow to soot through further aromatization in parall el with its reforming during gasification. Understanding of the chemistry and kinetics in a gasifier is important for developing low-temperature gasification. This work focused on numerical simulation of PAH reforming and soot formation in various coal typ es and gasification modes. A detailed chemical kinetic model was used for simulating a reductor of a two stage entrained flow gasifier under the gas composition determined by combination of experimental molecular composition of coal and inorganic gas compo sition at chemical equilibrium. O2/CO2-and O2 /H2O-blown modes significantly reduced the yield of PAHs and the formation of soot. Growth of soot particle was dominated by acetylene addition above 1300°C, while nucleation of soot precursors and PAH condensat ion became dominant at lower temperature.

DOI： 10.20550/jiesekitanronbun.56.0_56

1-22 Fate of hydrogen formed by growth of aromatic cluster during coal pyrolysis Reviewed

FUKUOKA Tetsuya, CHOI Cheolyong, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 56 ( 0 ) page： 44 - 45 2019.10

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

Changes in chemical structure of coal during carbonization are important factors to determine properties of softening and melting. It is believed that the caking properties are directly affected by transferable hydrogen, and its consumption lowers the degree of caking. Investigation of the fate of the hydrogen during carbonization is thus necessary for understanding the characteristics of caking. This work conducted quantitative analyses of the chemical structure of coke derived from caking and non-caking coal, together with an online gas analysis. As a result, the transferable hydrogen derived from the non-caking coal was partly consumed for decomposition of the functional groups such as ethers during carbonization, while that from the caking coal was little consumed.

DOI： 10.20550/jiesekitanronbun.56.0_44

1-13 Evaluation of CO2 absorption and regeneration performance of low-energy phase-separation solvent Reviewed

SUZUKI Takehiro, NISHIO Hitoshi, Tran Khuyen, YANASE Keiichi, MACHIDA Hiroshi, NORIANGA Koyo

Proceedings of Conference on Coal Science Vol. 56 ( 0 ) page： 26 - 27 2019.10

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

Carbon dioxide capture and storage (CCS) is expected to play a role in combating global warming. Thus,research and development are progressing around the world. However, there are limitations such as thedemonstration examples being limited to cases where the CO2 capture site and storage site are close. In recent years, Carbon dioxide Capture and Utilization (CCU) using captured CO2 has attracted attention.This time, we will focus on technologies that reduce CO2 and convert it into fuels and chemicals, mainly focusing on methanation. Energy saving can be achieved by integrating the CO2 capture process and the CO2 utilization process.In this paper, we report the results of energy calculation in the CO2 separation by the new process using the phase-separated type CO2 absorbent developed so far, and the experimental results of continuous operation using this process.

DOI： 10.20550/jiesekitanronbun.56.0_26

1-2-2 Detailed chemical kinetic modeling for conversion characteristics of sulfur compounds in a two-stage entrained flow coal gasifier Reviewed

ADACHI Nozomi, Choi Cheolyong, ZHANG Wei, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 28 ( 0 ) page： 10 - 11 2019.7

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

Toward developing an environmentally-friendly coal gasification process, a deeper understanding of chemistry and kinetics of reactions happening in a gasifier is of great importance. This work presents a numerical approach to predict conversion characteristics of sulfur compounds in a reductor of a two-stage entrained flow coal gasifier. A detailed chemical kinetic model consisting of 1951 reactions and 257 chemical species were used to calculate concentration profiles along with the reductor position at different gasification modes, temperature, and coal types. The sulfur compounds were mainly converted into H2S, whereas COS is a second major product at the reductor outlet and the formation is more enhanced at an O2/CO2-blowing mode than those at air-, and O2/H2O-blowing modes. The predicted total concentrations of H2S and COS are ranged between 400 and 800 ppm and agreed with the results obtained with an air-blowing 200 ton/day test coal gasification plant reported in the literature.

DOI： 10.20550/jietaikaiyoushi.28.0_10

2-1-2 Construction of CO2 methanation kinetic model based on experiment with catalyst fixed bed reactor Reviewed

Yasuda Shoya, Machida Hiroshi, Norinaga Koyo, Takano Hiroyuki, Izumiya Koichi

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 28 ( 0 ) page： 32 - 33 2019.7

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

Methanation CO2+4H2→CH4+2H2O discovered by Sabatier more than 100 years ago is an exothermic reaction that proceeds on a Ni-based catalyst. Catalysts with high activity and durability is now available and the research and development are currently shifting to a more practical stage including reactor design for demonstrating a large scale and a highly-efficient methanation process. This study is thus aiming at developing a global reaction model that can be applied for the numerical simulation with a computational fluid dynamics of a methanation reactor. Experiments using a catalyst fixed bed flow reactor were conducted and the rates of methanation reaction were measured under possible conditions happened at entire range of CO2 conversion rates. Power law and Langmuir Hinshelwood models were used to reproduce the experimental results and the rate parameters were determined with minimizing the difference between model calculations and experimental data.

DOI： 10.20550/jietaikaiyoushi.28.0_32

Reducing energy required for CO<inf>2</inf> separation and recovery process by employing phase separation solvents Reviewed

Continuous monitoring of char surface activity toward benzene Reviewed Open Access

Choi C., Shima K., Kudo S., Norinaga K., Gao X., Hayashi J.i.

Carbon Resources Conversion Vol. 2 ( 1 ) page： 43 - 50 2019.4

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

Kinetics of thermal decomposition of benzene on lignite-derived char was investigated at 900 °C by applying a new method to continuously monitor the char surface activity. Benzene vapor was continuously forced to pass through a micro fixed bed of char with residence time as short as 7.6 ms, and then detected continuously by a flame-ionization detector. Results showed the presence of two different types of char surfaces; consumptive Type I surface and non-consumptive (sustainable) Type II surface. Type I surface of a partially CO2-gasified char had an capacity of carbon deposit from benzene over 20 wt%-char and an initial activity (represented by a first-order rate constant) as high as 160 s−1. Both of them decreased with increasing carbon deposit due to consumption of micropores accessible to benzene, and finally became zero leaving Type II surface that had a very stable activity with rate constant of 4 s−1. The chars without gasification had capacities of Type I surfaces smaller by two orders of magnitude than the partially gasified char, while the Type II surfaces had activities similar to that of the partially gasified char. It was found that Type II surface converted benzene into not only carbon deposit but also diaromatics and even greater aromatics. Composition of the greater aromatics was unknown because they were deposited onto the reactor wall immediately after passing through the char bed.

DOI： 10.1016/j.crcon.2018.12.001

Effect of SiO<inf>2</inf> on loss of catalysis of inherent metallic species in CO<inf>2</inf> gasification of coke from lignite Reviewed Open Access

Choi C., Ashik U.P.M., Kudo S., Uebo K., Norinaga K., Hayashi J.i.

Carbon Resources Conversion Vol. 2 ( 1 ) page： 13 - 22 2019.4

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

Inherent metallic species retained by coal char or coke, such as Na and Ca, behave as catalysts in gasification. The char/coke normally contains inherent SiO2, which can react with the inherent catalysts to form silicates, resulting in catalyst deactivation over the range of pyrolysis, carbonization and gasification, and thereby reducing the char/coke reactivity. The present authors simulated the inherent catalyst deactivation experimentally by blending a Victorian lignite with SiO2, briquetting the SiO2/lignite blend, carbonizing the briquette, and then gasifying the coke with CO2. The kinetic analysis of the gasification employed a comprehensive model, which assumed progress in parallel of non-catalytic and catalytic gasification. The model quantitatively described the measured kinetics of the coke gasification with different SiO2 contents over a range of coke conversion up to 99.9%. The kinetic analysis revealed that the SiO2 deactivated substantial and entire portions of the most active catalyst and its precursor, respectively, before the gasification (i.e., during the carbonization). The catalyst deactivation also occurred during the gasification, but mainly following a self-deactivation mechanism that involved no silicates formation.

DOI： 10.1016/j.crcon.2018.09.002

An approach for quantifying transferable hydrogen in pyrolyzing coals Reviewed

Norinaga K., Fukuoka T., Machida H., Zhang W.

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

Norinaga K., Nishio H., Khuyen T., Machida H.

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

An approach for quantifying transferable hydrogen in pyrolyzing coals Reviewed

Norinaga K, Fukuoka T, Machida H, Zhang W

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

Reducing energy required for CO<inf>2</inf> separation and recovery process by employing phase separation solvents Reviewed

Norinaga K, Nishio H, Khuyen T, Machida H

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

No.2-19 Reducing energy required for CO2 separation/recovery process by employing amine/ether mixed absorbent Reviewed

MACHIDA Hiroshi, NISHIO Hitoshi, KHUYEN Tran, NORIANGA Koyo, ESAKI Takehiro

Proceedings of Conference on Coal Science Vol. 55 ( 0 ) page： 84 - 85 2018.10

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

It has been recognized that the CO2 separation and recovery process accounts around 60% of the total cost for operating CO2 capture and storage (CCS). The CO2 chemical absorption with a conventional amine solvent like monoethanol amine requires around 4 GJ/t-CO2 for CO2 recovery. Recently we developed phase separation solvent system which consists of not only amine but also hydrophobic solvent, ether. This system, before CO2 absorption, we have single phase, while after CO2 absorption, we have phase separation, one is CO2 rich phase and the other is CO2 lean phase. We can expect that the energy can significantly be reduced because it is not necessary to regenerate whole solvent but only the CO2 rich phase is to be regenerated. In this study, we examined the phase phenomena for 9 types of amine and a hydrophobic solvent mixture before and after CO2 absorption to find phase separation solvent system to minimize energy for CO2 recovery. Based on the observation, the mechanism for the phase separation and solvent regeneration is also discussed.

DOI： 10.20550/jiesekitanronbun.55.0_84

No.2-30 Chemical structure of coal and pyrolysis char and Quantitative evaluation of gas generation characteristics during pyrolysis Reviewed

FUKUOKA Tetsuya, MACHIDA Hiroshi, NORINAGA Koyo

Proceedings of Conference on Coal Science Vol. 55 ( 0 ) page： 110 - 111 2018.10

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

Changes in the chemical structure of coal during the dry distillation process and the composition and production characteristics of volatile components are important factors related to the mechanism of caking property development and the physical properties of coke masses and analyzed by various methods. However, up to now, analysis of volatile components and structural analysis of solid char are mostly performed individually, and it is difficult to combine both and to obtain quantitative knowledge on the thermal decomposition reaction mechanism. In this study, we tried to measure composition of dry distillation for caking coal and subbituminous coal using online gas analysis, and analyze changes of coal chemical structure using several spectroscopic methods (NMR, FT-IR, XPS etc.), integrated the obtained information to combine the former and the latter, and attempted to obtain new understanding of the coal dry distillation mechanism.

DOI： 10.20550/jiesekitanronbun.55.0_110

Computational Study on the Thermal Decomposition of Phenol-Type Monolignols Reviewed

Yuki Furutani, Yuki Dohara, Shinji Kudo, Jun-Ichiro Hayashi, Koyo Norinaga

International Journal of Chemical Kinetics Vol. 50 ( 4 ) page： 304 - 316 2018.4

Language：English Publishing type：Research paper (scientific journal) Publisher：John Wiley and Sons Inc.

A detailed chemical kinetic model has been developed to theoretically predict the pyrolysis behavior of phenol-type monolignol compounds (1-(4-hydroxyphenyl)prop-2-en-1-one, HPP
p-coumaryl alcohol, 3-hydroxy-1-(4-hydroxyphenyl)propan-1-one, HHPP
1-(4-hydroxyphenyl)propane-1,3-diol, HPPD) released from the primary heterogeneous pyrolysis of lignin. The possible thermal decomposition pathways involving unimolecular decomposition, H-addition, and H-abstraction by H and CH3 radicals were investigated by comparing the activation energies calculated at the M06–2X/6–311++G(d,p) level of theory. The results indicated that all phenol-type monolignol compounds convert to phenol by side-chain cleavage. p-Coumaryl alcohol decomposes into phenol via the formation of 4-vinylphenol, whereas HPP, HHPP, and HPPD decompose into phenol via the formation of 4-hydroxybenzaldehyde. The pyrolytic pathways focusing on the reactivity of the hydroxyl group in HPP and producing cyclopentadiene (cyc-C5H6) were also investigated. The transition state theory (TST) rate constants for all the proposed elementary reaction channels were calculated at the high-pressure limit in the temperature range of 300–1500 K. The kinetic analysis predicted the two favorable unimolecular decomposition pathways in HPP: the one is the dominant channel below 1000 K to produce cyc-C5H6, and the other is above 1000 K to yield phenol (C6H5OH).

DOI： 10.1002/kin.21164

Characteristic Properties of Lignite to Be Converted to High-Strength Coke by Hot Briquetting and Carbonization Reviewed

Shinji Kudo, Aska Mori, Gentaro Hayashi, Takuya Yoshida, Noriyuki Okuyama, Koyo Norinaga, Jun-Ichiro Hayashi

Energy and Fuels Vol. 32 ( 4 ) page： 4364 - 4371 2018.4

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

A sequence of hot briquetting and carbonization (HBC) is a promising technology for the production of coke with a high mechanical strength from lignite, but factors affecting the coke strength have not yet been fully understood. The HBC cokes prepared from 12 lignites in this study showed diverse tensile strength (e.g., from 0.2 to 31.2 MPa in the preparation at 200 °C and 112 MPa for hot briquetting and 1000 °C for carbonization), and the coke strengths could not be explained by differences in commonly used structural properties of the parent lignites, such as elemental composition and contents of volatile matter/fixed carbon and ash. In this study, two methods were proposed for correlating the coke strength with the lignite properties, which employed the chemical structure analyzed by solid-state 13C nuclear magnetic resonance or the volumetric shrinkage during carbonization. A stronger coke was obtained from lignite that contained more aliphatic carbons (less aromatic carbons) or shrank more considerably. These characteristics contributed to intensified compaction of lignite in the briquetting and suppression of the formation of large pores, which are a cause of coke fracture. Two empirical equations, predicting the coke strength from the parameters of lignite properties, were established to be criteria for selection of lignite as HBC coke feedstock, although further investigation with more experimental data would be necessary for the validation.

DOI： 10.1021/acs.energyfuels.7b03155

CO2 Gasification of Sugar Cane Bagasse: Quantitative Understanding of Kinetics and Catalytic Roles of Inherent Metallic Species Reviewed

Zayda Faizah Zahara, Shinji Kudo, Daniyanto, U. P.M. Ashik, Koyo Norinaga, Arief Budiman, Jun-Ichiro Hayashi

Energy and Fuels Vol. 32 ( 4 ) page： 4255 - 4268 2018.4

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

A total of 18 chars from the pyrolysis of six trios of sugar cane bagasses (SCBs
original, water-washed, and acid-washed) were gasified with CO2 at 900 °C, aiming at a quantitative description of the rate of gasification catalyzed by inherent metallic species and a correlation of the catalytic activity and its change during the gasification with the metallic species composition. The measured kinetics was described quantitatively over a range of char conversion, 0-0.999, by a model that assumed progress in parallel of the catalytic gasification and non-catalytic gasification, together with the presence of a catalytic precursor and three to four types of catalysts having different activities and deactivation characteristics. A series of regression analyses was scrutinized and reached expression of initial catalytic activity as a linear function of Na, K, Ca, Fe, and Si concentrations in the char with a correlation factor (r2) of &gt
0.98. The catalyst precursor contributed fully by water-soluble Na, K, and Ca. Si was responsible for the catalyst deactivation during the pyrolysis but not during the gasification. The chars produced from original SCBs followed a linear relationship between the initial catalytic deactivation rate and initial activity (r2 &gt
0.99), while such a linear relationship was not valid for those formed from the water-washed SCBs. This was explained mainly by more rapid deactivation of the Fe catalyst in the chars from water-washed SCBs than that in the chars formed from the original SCBs. Na and K in char from the original SCBs, originating from the water-soluble SCBs, chemically interacted with the Fe catalyst, slowing its deactivation.

DOI： 10.1021/acs.energyfuels.7b03147

Energy-saving CO<inf>2</inf> Capture Process Using Phase Separation Type Solvent by Aqueous (amine + ether) Solution Reviewed

Machida H., Takehiro E., Yamaguchi T., Norinaga K., Kishimoto A., Akiyama K., Nishimura M.

GHGT 2018 - 14th International Conference on Greenhouse Gas Control Technologies 2018

Language：English Publishing type：Research paper (scientific journal) Publisher：GHGT 2018 - 14th International Conference on Greenhouse Gas Control Technologies

We have developed the phase separation solvent for CO2 capture. Our developed solvent consists amine, organic solvent and water and shows single liquid phase before CO2 absorption though it shows two liquid phases after CO2 absorption. Feature of phase separation solvent is reducing temperature difference between absorber and stripper. We apply the heat pump system for CO2 separation and evaluate the energy consumption. Low temperature swing process saves energy requirement for CO2 capture process with highly-effective reaction-heat recovering. To evaluate the CO2 capture system with our solvent, screening test for amine and organic solvent combination and CO2 solubility measurement were examined. In the phase separation test, three types of solvents were obtained by combining amine and ether, that is, no phase separation with CO2 scrubbing, phase separation with CO2 scrubbing, and thoroughly immiscible. The phase behaviour depends on the hydrophobicity of amines or organic solvents, and the types of solvents were classified using the hydrophobic parameter.

Current situation and future scope of biomass gasification in Japan Open Access

Furutani, Y, Norinaga, K, Kudo, S, Hayashi, J.-I, Watanabe, T

Evergreen Vol. 4 ( 4 ) page： 24 - 29 2017.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Transdisciplinary Research and Education Center for Green Technologies, Kyushu University

In this study, we investigated current situation of biomass gasification plants in 5 cities (c.a. Murayama City, Chichibu City, Ueno Village, Oshu City and Yamaguchi City) in Japan, and make R&D policy proposals to expand the biomass gasification plants. Four cities have commonly promoted the efficient heat utilization such as snow melting, drying the wood and supplying hot water into mushroom bed and hot spring. However, heat utilization is limited in a small area because heat loss is generated during the long-distance transportation. In order to obtain energy forms suitable for the long-distance transportation, such as hydrogen gas and electricity, the R&D of biomass gasification with hydrogen production or combined with Solid Oxide Fuel Cell (SOFC) should be promoted in the future.

DOI： 10.5109/1929681

7-2-4 Development of energy-saving CO2 capture process using phase separation absorbent Reviewed

MACHIDA Hiroshi, ESAKI Takehiro, YAMAGUCHI Tsuyoshi, HORIZOE Hirotoshi, NORINAGA Koyo, KISHIMOTO Akira, MATSUOKA Akira, AKIYAMA Katsuya, NISHIMURA Makoto

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 26 ( 0 ) page： 228 - 229 2017

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

Phase separation type CO2 capture solvent was developed which transforms into two liquid phases after CO2 absorption. At first, we checked the phase phenomena of 9 types of amine and 3 types of polyether combinations. There shows three types; keeping one liquid phase before and after CO2 absorption, transforming into two liquid phase after CO2 absorption, forming initially two liquid phases. CO2 solubility of the developed phase separation solvent was measured. The results show that the phase separation solvent can reduce the temperature difference between absorber and desorber than that of conventional amine solvent. Required energy for CO2 capture using phase separation solvent was estimated under 2.0 GJ/ton-CO2.

DOI： 10.20550/jietaikaiyoushi.26.0_228

P-3-3 Detailed Chemical Kinetic Modeling of Primary and Secondary Pyrolysis of Lignin Reviewed

FURUTANI Yuki, DOHARA Yuki, KUDO Shinji, HAYASHI Jun-ichiro, NORINAGA Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 26 ( 0 ) page： 268 - 269 2017

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

A set of lignin pyrolysis processes involving primary pyrolysis and secondary vapor-phase reactions were described with a detailed chemical kinetic model (DCKM). The DCKM of primary pyrolysis, which characterizes lignin structures as three model compounds, predicted the yields of volatiles (c.a. 22 gas species and 10 monolignols) derived from primary pyrolysis. The original DCKM of secondary vapor-phase reactions did not involve the kinetic database on vapor-phase reaction of monolignols. Thus, the pyrolytic pathways of 1-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-en-1-one (HDPP) accounted for 60 - 80 wt% of total monolignol species were proposed, and total 230 elementary reaction rate constants obtained by ab initio theory were added into the original kinetic database. The simulation of secondary vapor-phase reaction was performed using the volatile composition predicted by the DCKM of primary pyrolysis as a boundary condition. The established kinetic models successfully reproduced the yields of H2O and char, but at high temperature overestimated tar yield and underestimated CO yield. This is probably due to the insufficient kinetic model of the secondary vapor phase reaction, which did not include the decomposition pathways of the monolignols except for HDPP.

DOI： 10.20550/jietaikaiyoushi.26.0_268

A Supported Ni Catalyst Produced from Ni-Al Hydrotalcite-Like Precursor for Reduction of Furfuryl Alcohol to Tetrahydrofurfuryl Alcohol by NaBH4 in Water Reviewed

Ren, DZ; Wang, JY; Jiang, XL; Song, ZY; Norinaga, K; Huo, ZB

CHEMISTRYSELECT Vol. 6 ( 4 ) page： 551 - 556 2021.1

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

Tetrahydrofurfuryl alcohol (THFA) is a kind of high value-added compound in industry, which can be obtained from biomass chemical engineering. However, Synthesis of THFA under mild condition with green hydrogen donors remains a big challenge. In this article, a supported Ni catalyst derived from Ni−Al hydrotalcite-like compounds (HTs) as precursors for the reduction of furfuryl alcohol (FA) into THFA with NaBH4 as reducing agent in water was first reported. As a result, Ni/Al2O3−HT exhibited high catalytic activity for the transformation, and THFA was achieved in 100 % yield at 60 °C for 60 min. Moreover, Ni/Al2O3−HT could be recycled at least seven times without the loss of its activity. Under optimized conditions, the reduction reaction of several furan and ketone compounds was investigated. A possible mechanism for the reduction of FA to afford THFA was also proposed.

DOI： 10.1002/slct.202003543

Lattice Boltzmann simulation of multicomponent reaction-diffusion and coke formation in a catalyst with hierarchical pore structure for dry reforming of methane Reviewed Open Access

Lin, YX; Yang, C; Choi, CY; Zhang, W; Machida, H; Norinaga, K

CHEMICAL ENGINEERING SCIENCE Vol. 229 2021.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Engineering Science

In order to further enhance catalytic activity and inhibit carbon formation, the hierarchical structure-performance relationship has been investigated in dry reforming of methane (DRM). A modified random generation of macro-mesopores (RGMMP) algorithm was adopted to model the structure of the catalyst with macropore and mesopore. Based on multi-component non-continuum reaction-diffusion lattice Boltzmann model, the effects of three hierarchical pore geometrical parameters, namely the catalyst porosity, the ratio of mesopore volume to macropore volume and the ratio of average macropore diameter to average mesopore diameter, on coke formation and catalytic performance were investigated to elucidate the deactivation and reaction-diffusion mechanism of the catalyst in DRM. Based on the competitive relationship between heterogeneous reaction and intraparticle diffusion, the optimal values to define hierarchical pore structure have been identified, which provides maximum catalytic performance and coking resistance for a reaction condition.

DOI： 10.1016/j.ces.2020.116105

Prediction of Phase Behavior of CO2 Absorbents Using Conductor-like Screening Model for Real Solvents (COSMO-RS): An Approach to Identify Phase Separation Solvents of Amine/Ether/Water Systems upon CO2 Absorption Reviewed

Nakaoka, M; Tran, KVB; Yanase, K; Machida, H; Norinaga, K

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH Vol. 59 ( 42 ) page： 19020 - 19029 2020.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Industrial and Engineering Chemistry Research

Developing energy-saving absorbents for carbon dioxide (CO2) is essential for improving carbon capture and storage (CCS) technologies. Recently, we have designed phase separation solvents, which can significantly reduce the regeneration energy for CO2 capture and separation down to 1.6 GJ/ton-CO2 [ Machida, H.; et al. Int. J. Greenhouse Gas Control2018, 75, 1-7 ]. For further developing better solvents, this paper studied a theoretical approach with conductor-like screening model for real solvents (COSMO-RS) to screen the amine/ether/water systems to identify phase separation solvents upon CO2 absorption. In this work, liquid-liquid equilibria of 21 amine/ether/water systems were determined both before and after CO2 absorption. Experimentally, it has already been demonstrated that the phase behavior of these systems is classified into three categories: phase separation type, miscible type, and immiscible type. This study demonstrates that the octanol/water partition coefficient is empirically able to search for a combination of amine and ether compounds, in which the system exhibits the phase separation behavior by absorbing CO2. The COSMO-RS calculations successfully reproduced experimental phase behavior with a rate of agreement of more than 80% by accounting the following two factors: (i) ion pairing for the description of the association/dissociation state for ionic species and (ii) relevant low-lying conformations of ether and amine, which are rationalized by experiments such as conductivity and excess enthalpy measurements. Moreover, we also validated the ability of the COSMO-RS calculation to qualitatively describe the compositions of 2-(ethylamino)ethanol, diethylene glycol diethyl ether, and water in CO2-rich and CO2-lean phases at varying CO2 loading conditions.

DOI： 10.1021/acs.iecr.0c03233

Energy-Saving CO2 Capture by H-2 Gas Stripping for Integrating CO2 Separation and Conversion Processes Reviewed

水素を用いた省エネルギー CO₂ 回収技術

町田洋，柳瀬慶一，チャンクウィン，山口毅，則永行庸

クリーンエネルギー Vol. 29 ( 10 ) page： 17 - 22 2020.10

水素を用いた省エネルギー CO₂ 回収技術 Invited Reviewed

町田洋, 柳瀬慶一, チャンクウィン, 山口毅, 則永行庸

クリーンエネルギー Vol. 29 ( 10 ) page： 17 - 22 2020.10

メタネーション大規模実証に向けた基盤研究およびCO2分離回収と利用の統合プロセスに関する研究開発

則永行庸、張煒、チェチョルヨン、柳瀬慶一、チャンクウィン、町田洋

Adsorption News Vol. 34 ( 2 ) page： 18 - 22 2020.7

メタネーション大規模実証に向けた基盤研究およびCO2分離回収と利用の統合プロセスに関する研究開発 Invited Reviewed

則永行庸, 張煒, チェチョルヨン, 柳瀬慶一, チャンクウィン, 町田洋

Adsorption News Vol. 34 ( 2 ) page： 18 - 22 2020.7

Machida Hiroshi, Esaki Takehiro, Yamaguchi Tsuyoshi, Norinaga Koyo

ACS SUSTAINABLE CHEMISTRY & ENGINEERING Vol. 8 ( 23 ) page： 8732 - 8740 2020.6

Carbon Dioxide Absorption Heat in Liquid-Liquid and Solid-Liquid Phase-Change Solvents Using Continuous Calorimetry Reviewed

Tran Khuyen V. B, Ando Ryuya, Yamaguchi Tsuyoshi, Machida Hiroshi, Norinaga Koyo

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH Vol. 59 ( 8 ) page： 3475 - 3484 2020.2

Computational fluid dynamics simulation of CO2 methanation in a shell-and-tube reactor with multi-region conjugate heat transfer Reviewed

Zhang Wei, Machida Hiroshi, Takano Hiroyuki, Izumiya Koichi, Norinaga Koyo

CHEMICAL ENGINEERING SCIENCE Vol. 211 2020.1

Modelling of CO<inf>2</inf> solubility in phase separation solvent composed of amine/ether/water system for CO<inf>2</inf> capture Reviewed

Machida, H., Ando, R., Esaki, T., Yamaguchi, T., Norinaga, K.

Journal of Molecular Liquids Vol. 292 2019.10

Quantitative Description of Catalysis of Inherent Metallic Species in Lignite Char during CO2 Gasification Reviewed

Halim Nurulhuda, Ashik U. P. M, Gao Xiangpeng, Kudo Shinji, Sanwani Edy, Norinaga Koyo, Hayashi Jun-ichiro

ENERGY & FUELS Vol. 33 ( 7 ) page： 5996 - 6007 2019.7

Production of High-strength Cokes from Non-/Slightly Caking Coals. Part I: Effects of Coal Pretreatment and Variables for Briquetting and Carbonization on Coke Properties Reviewed Open Access

Matoba Masahiro, Kudo Shinji, Mori Aska, Norinaga Koyo, Uchida Kenya, Dohi Yusuke, Uebo Kazuya, Hayashi Jun-ichiro

ISIJ INTERNATIONAL Vol. 59 ( 8 ) page： 1440 - 1448 2019

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

In continuation of the present authors’ studies on production of high strength coke from lignite by sequential binderless hot briquetting and carbonization, this study has been carried out aiming at proposing methods to produce high strength coke from non-/slightly caking coals of subbituminous to bituminous rank. This paper firstly demonstrates preparation of cokes with cold tensile strengths above 10 MPa from two single non-caking coals (particle size; < 106 µm) by applying briquetting at temperature and mechanical pressure of over 200°C and 100 MPa, respectively. Such strength of coke is obtained over a wide range of heating rate, 3–30°C/min, during carbonization with final temperature of 1000°C. Then, a simple pretreatment, fine pulverization of coal to particle sizes smaller than 10 or 5 µm, is examined. This pretreatment enables to prepare coke with tensile strength even over 25 MPa, by decreasing porosity of resulting coke and more extensively the size of macropores simultaneously. The coke strength changes with carbonization temperature having a particular feature; significant development of strength at 600–1000°C, i.e., after completion of tar evolution, in which macropores and non-porous (dense) part of coke shrink in volume, inducing bonding and coalescence of particles and thereby arising the strength.

DOI： 10.2355/isijinternational.ISIJINT-2018-819

Quantitative Analyses of Chemical Structural Change and Gas Generation Profile of Coal upon Heating toward Gaining New Insights for Coal Pyrolysis Chemistry Reviewed Open Access

Fukuoka Tetsuya, Takeda Norihiro, Zhang Lu, Machida Hiroshi, Zhang Wei, Watanabe Masahiko, Nishibata Yuko, Hayashi Jun-ichiro, Norinaga Koyo

ISIJ INTERNATIONAL Vol. 59 ( 8 ) page： 1376 - 1381 2019

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

Chemical structure of coal is evolutionary changed during pyrolysis that accompanies gas release. The chemical structural change and gas formation profiles play important roles in determining caking property and physical properties such as strength and size of the resultant coke. However, analyses of volatile components and structural analysis of solid char have been mostly performed individually, and it is difficult to combine both and to obtain quantitative understanding on the thermal decomposition of coal at mechanistic level. In this study, simultaneous analyses of solid chemical structures of the heat treated coals and gas formation profiles were conducted for two kinds of coals that were pyrolyzed at an identical condition. On-line gas analysis with a quadrupole mass spectrometer and spectroscopic methods (NMR and FT-IR) were employed for quantitative evaluation of gas formation characteristics and solid chemical structure, respectively. The information obtained were then integrated to acquire new insight for coal pyrolysis mechanism. Here an approach to quantify the transferable hydrogen that contributes to stabilize radicals formed in pyrolyzing coal was proposed. It includes the quantitative assessment of aromatic cluster growth, decomposition of hydroxyls, and releases of hydrogen and pyrolytic water into gas phase. The proposed approach suggested that a bituminous coal that exhibits plasticity during pyrolysis had 3.5 mol/kg-coal transferable hydrogen, whereas the amount of transferable hydrogen of the sub-bituminous coal, a non-caking coal, was 1.3 mol/kg-coal, during pyrolysis up to 500°C.

DOI： 10.2355/isijinternational.ISIJINT-2018-816

Production of High-strength Cokes from Non-and Slightly Caking Coals. Part II: Application of Sequence of Fine Pulverization of Coal, Briquetting and Carbonization to Single Coals and Binary Blends Reviewed Open Access

Uchida Kenya, Kudo Shinji, Mori Aska, Ashik U. P. M, Norinaga Koyo, Dohi Yusuke, Uebo Kazuya, Hayashi Jun-ichiro

ISIJ INTERNATIONAL Vol. 59 ( 8 ) page： 1449 - 1456 2019

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

Sequential coal briquetting and carbonization was applied to preparation of cokes from 9 non- or slightly caking coals with carbon contents (fC) of 67–85 wt%-daf. Coal pulverization to sizes of <106 µm and briquetting at 40°C enabled to prepare cokes with tensile strength (σ) over 10 MPa from 4 coals with fC of 82–85 or 67 wt%-daf. Then, by introducing fine pulverization to sizes of < 10 µm before the briquetting, 7 coals were converted successfully into cokes with σ = 11–25 MPa. Increasing the briquetting temperature to 240°C further increased σ to 19–35 MPa for all the 9 coals. It was thus demonstrated that the hot briquetting of finely pulverized coal was a method to prepare high strength coke regardless of the rank of parent coal. Cokes were also prepared from 14 binary coal blends. All the cokes prepared by applying the fine pulverization and hot briquetting had σ of 20–35 MPa, which agreed well with that calculated by weighted average of those from the component coals. On the other hand, positive and also negative synergistic effects of blending occurred when blends were briquetted at 40°C. Characteristics of bonding/coalescence among particles of different types of coals were responsible for such synergies.

DOI： 10.2355/isijinternational.ISIJINT-2018-847

An approach for quantifying transferable hydrogen in pyrolyzing coals Reviewed

Norinaga K

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

Reducing energy required for CO<inf>2</inf> separation and recovery process by employing phase separation solvents Reviewed

Norinaga K

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

An approach for quantifying transferable hydrogen in pyrolyzing coals Reviewed

Norinaga K

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

Reducing energy required for CO<inf>2</inf> separation and recovery process by employing phase separation solvents Reviewed

Norinaga K

36th Annual International Pittsburgh Coal Conference: Clean Coal-Based Energy/Fuels and the Environment, PCC 2019 2019

Characteristics of gas evolution profiles during coal pyrolysis and its relation with the variation of functional groups Reviewed Open Access

Zhang, L, Qi, S, Takeda, N, Kudo, S, Hayashi, J, Norinaga, K

International Journal of Coal Science and Technology Vol. 5 ( 4 ) page： 452 - 463 2018.12

Effects of HZSM-5 on volatile products obtained from the fast pyrolysis of lignin and model compounds Reviewed

Yang Huamei, Norinaga Koyo, Li Ji, Zhu Wenyou, Wang Haijun

FUEL PROCESSING TECHNOLOGY Vol. 181 page： 207 - 214 2018.12

Prediction of hot coke oven gas reforming by LES coupled with the extended flamelet/progress variable approach Reviewed

Panlong Yu, Koyo Norinaga, Hiroaki Watanabe, Toshiaki Kitagawa

Fuel Vol. 231 page： 234 - 243 2018.11

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

Large-eddy simulation (LES) coupled with the extended flamelet/progress variable approach (EFPV) has been performed to predict characteristics of reacting flows in a bench-scale hot coke oven gas (HCOG) reformer. In order to investigate the capability of capturing effects of operating conditions, simulations were carried out in two different cases in which the coke oven gas temperature and oxygen ratio were altered. Results showed that the LES coupled with the EFPV performed very well in terms of predicting temperature distribution as well as the temperature variation trend between the two cases. In addition, major species such as H2, CO, CO2, H2O and CH4, as well as minor species like benzene and some typical polycyclic aromatic hydrocarbons (PAH) were analyzed to illustrate their activities and dominant chemical events. With regards to the composition of the dry reformed gas, comparisons were made between the experimental data and the numerical simulation results, and reasonable results have been obtained. It has been confirmed that the general feature of the reacting flows in the HCOG reformer can be precisely captured by the present LES.

DOI： 10.1016/j.fuel.2018.05.104