研究者詳細 - 町田　洋

論文 - 町田　洋

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Numerical investigation of polycyclic aromatic hydrocarbons (PAHs) and soot formation from various coals in a two-stage entrained flow gasifier with detailed chemistry

Li, TL; Fukumoto, K; Zhang, LJ; Lin, YX; Choi, C; Machida, H; Norinaga, K

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS 188 巻 2025年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Analytical and Applied Pyrolysis

The substitution of air with O2/CO2 atmosphere is a promising solution for CO2 recirculation during coal gasification. However, a comprehensive understanding on the formation mechanism of PAHs and soot under different conditions is necessary to reduce their emissions. This work presents simulation results of a two-stage entrained flow coal gasifier in a 250 MW industrial-scale plant using detailed chemistry. The influences of reductor temperature (1000–1200 ℃) and coal types (bituminous coal, sub-bituminous coal, and lignite) on PAHs and soot formations from the coal volatiles in the reductor were simulated through a detailed chemical kinetic model under air and O2/CO2 atmospheres. Results show that 2- and 3-ring aromatics are main PAHs products. Rising temperature has inhibitory effects on PAHs formation, especially for lignite. The O2/CO2 condition reduces the PAHs yield compared with the air condition. Rate of production analysis reveals that conversion of major PAHs occurs mainly between PAHs and their radicals. Vinyl-naphthyl radical and indenyl radical play an important role in the acenaphthylene conversion. In addition, soot production increases with a higher temperature under both air and O2/CO2 conditions. The O2/CO2 condition effectively suppressed soot production through a weaker HACA surface growth route than the air condition. lignite produces the least soot, and sub-bituminous coal produces the most. This study deeply reveals the formation mechanisms of PAHs and soot in a two-stage entrained flow gasifier through detailed chemical kinetic modeling, giving an insight into the complex PAHs and soot formations to assess the design and the operating condition of gasifier with O2/CO2 injection.

DOI： 10.1016/j.jaap.2025.107027

Mechanism investigation of direct electrochemical reduction of CO<sub>2</sub>-loaded 2-(ethylamino)ethanol solution into CO

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

SEPARATION AND PURIFICATION TECHNOLOGY 355 巻 2025年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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<sub>2</sub> methanation process and techno-economic analysis with CO<sub>2</sub> capture from the flue gas of automotive shredder residue 査読有り

Wasnik, CG; Nakamura, M; Machida, H; Ito, J; Shiratori, K; Norinaga, K

CHEMICAL ENGINEERING JOURNAL 507 巻 2025年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

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

CHEMICAL ENGINEERING SCIENCE 305 巻 2025年2月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Nickel/Zirconia-Catalyzed CO<sub>2</sub> Methanation in Differential and Integral Fixed-Bed Reactors: Experimental and Computational Fluid Dynamics Studies 査読有り

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

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 64 巻 ( 3 ) 頁： 1473 - 1487 2025年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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 査読有り

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

APPLIED THERMAL ENGINEERING 258 巻 2025年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

Li, Q; Machida, H; Norinaga, K

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 63 巻 ( 44 ) 頁： 19063 - 19075 2024年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Modeling and uncertainty quantification of CO<sub>2</sub> absorption process using phase separation solvent 査読有り

Yuyama, S; Machida, H; Yajima, T; Kawajiri, Y

CHEMICAL ENGINEERING SCIENCE 298 巻 2024年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Engineering Science

Absorption using an amine solvent is one of the primary means for capturing CO2 from many combustion sources such as fossil fuel power plants. CO2 capture systems by absorption need a large amount of thermal energy to strip CO2 from the amine solvent. In recent years, absorption using a phase separation solvent, which forms two phases when CO2 is absorbed, has been demonstrated as a promising technique to reduce the energy consumption. In this study, we examine several process models for the CO2 absorption process using a phase separation solvent, and quantify the uncertainty of the model parameters. We estimated model parameters, including equilibrium and mass transfer parameters, from two sources of experimental data: solubility tests, as well as lab-scale absorber tests. Model parameters were estimated by Bayesian inference using the Markov chain Monte Carlo method. The proposed approach successfully quantified the uncertainties of the model parameters.

DOI： 10.1016/j.ces.2024.120348

LNG Oxy-Fuel Power and Green Methanol Poly Generation Systems Associated with CO<sub>2</sub> Condensation Capture: Techno-Economic Environmental Assessment 査読有り

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

ENERGY & FUELS 38 巻 ( 14 ) 頁： 13089 - 13103 2024年7月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Environmental-friendly extraction of di(2-ethylhexyl) phthalate from poly (vinyl chloride) using liquefied dimethyl ether 査読有り

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

WASTE MANAGEMENT 183 巻頁： 21 - 31 2024年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Energy optimization of a non-aqueous solvent CO<sub>2</sub> absorption system with pressure swing regeneration 査読有り

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

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL 135 巻 2024年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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 CO<sub>2</sub> Solubility Measurement in Miscible and Liquid-Liquid Phase Separation Types of Amine Solvent Using Headspace Gas Chromatography

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

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 63 巻 ( 13 ) 頁： 5823 - 5832 2024年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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 CO<sub>2 </sub>hydrogenation under uncertain product prices

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

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 54 巻頁： 635 - 651 2024年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

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

Carbon Resources Conversion 2024年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

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

FUEL 349 巻 2023年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Fuel

This paper reports a computational fluid dynamics simulation of carbon dioxide (CO2) methanation via the Sabatier process in a shell-and-tube reactor, incorporating a water phase change simulation on the shell side using the volume of fluid (VOF) method. The essential heat removal factors and their mechanisms, such as the catalyst size, bed porosity, thermal conductivity, coolant flow rate, and coolant boiling, were primarily investigated. The computational code was a newly developed in-house version of ChtMultiRegionFOAM based on OpenFOAM v2006. This code can simulate catalyst-gas heat transfer, which is called the two-temperature model. The code was extended to new methanation and phase-change models based on the VOF method. The computational code was first validated using existing experimental data. After sufficient accuracy was confirmed, several parametric studies were conducted. Catalyst heat conductivity was the most influential factor among the catalyst-related parameters. The flow rate of the oil coolant significantly affected the cooling performance. Finally, the use of boiling water significantly reduced the coolant flow rate. Moreover, the cooling performance remained unchanged until the total heat release rate from the gas exceeded the total latent heat of the water.

DOI： 10.1016/j.fuel.2023.128126

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

Li, TL; Choi, C; Fukomoto, K; Machida, H; Norinaga, K

FUEL 343 巻 2023年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Fuel

The injection of CO2 with coal into coal gasifier is a promising approach to achieve CO2 recirculation. Predicting the formation and evolution of polycyclic aromatic hydrocarbons (PAHs) and soot during coal gasification is particularly important as their presence poses challenges to the gasifier operation and environment. However, the effect of CO2 injection on their formation must be elucidated in more detail to optimize the gasifier design. This work investigates PAHs and soot formations in gas-phase reactions under different gasifying agents (Air, O2/CO2, O2/H2O) in a two-stage entrained flow coal gasifier using a detailed chemical kinetic model (DCKM). Under the O2/CO2– and O2/H2O-blown conditions, aromatics reforming was progressed whereas the yields of tar and soot were effectively suppressed. The benzene was observed as the most abundant PAHs species, followed by naphthalene and acenaphthalene. Regarding the relative oxygen concentration, the conversion behavior of aromatics was significantly influenced in the O2/CO2-blown condition, while the somewhat effect was found in the O2/H2O-blown condition. Tar yield peaked at 50% relative oxygen concentration in the O2/CO2-blown condition. The present finding may have practical significance in the O2/CO2-blown gasifier to facilitate CO2 recirculation for the oxy-fuel IGCC system.

DOI： 10.1016/j.fuel.2023.127876

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

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

HELIYON 9 巻 ( 4 ) 2023年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

CHEMICAL ENGINEERING SCIENCE 268 巻 2023年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

APPLIED THERMAL ENGINEERING 218 巻 2023年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

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

Journal of Advanced Manufacturing and Processing 5 巻 ( 1 ) 2023年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

Zhang, LJ; Uehara, Y; Nakamura, M; Choi, C; Liu, C; Machida, H; Hayashizaki, H; Kawai, Y; Hata, Y; Norinaga, K

ISIJ INTERNATIONAL 63 巻 ( 9 ) 頁： 1441 - 1450 2023年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ISIJ International

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

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

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

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS 166 巻 2022年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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 CO<sub>2</sub> Electrochemical Reduction by a Robust Electrocatalyst Fabricated by Electrodeposition of Indium and Zinc over Copper Foam

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

ACS APPLIED ENERGY MATERIALS 5 巻 ( 8 ) 頁： 9846 - 9857 2022年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

ENERGY CONVERSION AND MANAGEMENT 265 巻 2022年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Phase equilibrium modeling of mixtures containing conformationally flexible molecules with the COSMO-SAC model

Hung, YC; Hsieh, CM; Machida, H; Lin, ST; Shimoyama, Y

JOURNAL OF MOLECULAR LIQUIDS 356 巻 2022年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

The multi-conformational structures sampling of a molecule, considered as conformational information, is found to be crucial for applying COSMO-SAC to systems containing compounds with flexible molecular structures, such as alkylene glycol derivatives. In this study, a hybrid modeling approach that combines the COSMO-SAC model with classical molecular dynamics (MD) is proposed to investigate the phase behavior of systems containing alkylene glycol derivatives. The accuracy in predicting liquid–liquid equilibrium (LLE) was found to be strongly influenced by conformational populations obtaining from MD simulations under different solvation environments. The overall root mean square deviation (RMSD) in predicting LLE mutual solubility from COSMO-SAC for seven selected mixtures containing alkylene glycol derivatives reduces from 19.1% to 10.1% when conformation distribution is included. The new approach significantly improves the accuracy in predicting phase behaviors for alkylene glycol derivatives solutions and can be applied to systems containing compounds with flexible molecular structures.

DOI： 10.1016/j.molliq.2022.118896

Modeling of phase separation solvent for CO<sub>2</sub> capture using COSMO-SAC model

Hung, YC; Hsieh, CM; Machida, H; Lin, ST; Shimoyama, Y

JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS 135 巻 2022年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of the Taiwan Institute of Chemical Engineers

Background: Phase separation solvents are proposed to replace conventional solvents for CO2 capture due to a significant reduction of absorbent regeneration heat. A predictive approach based on COSMO-SAC is developed to model the CO2 capture process using the phase separation solvent of 2-(ethylamino)ethanol (EAE) + water + diethylene glycol diethyl ether (DEGDEE). Methods: In this approach, liquid phase compositions, including CO2 solubility, are determined from vapor-liquid-liquid equilibrium calculation with a chemisorption reaction in both liquid phases. The behavior of phase separation after CO2 capture and CO2 solubility in both CO2-lean and CO2-rich phases at 313 and 353 K can be well described by the proposed approach. Significant findings: The overall root-mean-square-deviation (RMSD) in predicting compositions (128 data points) of all components in both liquid phases is 0.064, which is slightly better than a previous study on the accuracy of COSMO-SAC in LLE prediction (RMSD = 0.105). The phase separation behavior of solvent can be realized with the hydrophilic product upon CO2 absorption from the σ-profile analysis. The proposed framework is expected to be a useful tool for the development of a new phase separation solvent.

DOI： 10.1016/j.jtice.2022.104362

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

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

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 47 巻 ( 34 ) 頁： 15254 - 15269 2022年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Unveiling the mechanism of CO<sub>2</sub>-driven phase change in amine plus water plus glycol ether ternary mixture

Hung, YC; Hsieh, CM; Machida, H; Lin, ST; Shimoyama, Y

JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS 131 巻 2022年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of the Taiwan Institute of Chemical Engineers

Background: Phase separation solvents have been developed for CO2 capture with the advantage of low regeneration energy. Understanding the mechanism of phase change driven by CO2 capture is critical toward design of phase separation solvents. Methods: In this work, the molecular information of σ-profile and simulated ternary liquid–liquid equilibrium (LLE) phase diagram obtained from a predictive modeling based on COSMO-SAC method is used to investigate the phase behavior of phase separation solvents before and after CO2 absorption. Significant findings: Ternary mixtures of three selected amines [2-aminoethanol (MEA), 2-(ethylamino)ethanol (EAE), 2-(butylamino)ethanol (BAE)] + water + glycol ether, with different strengths of hydrophilicity of amines, exhibit three types of partially miscible behaviors. Upon absorption of CO2, amine reacts to form hydrophilic reaction products (carbamate + protonated amine), resulting in the change of the molecular interactions and immiscible behaviors. Our study shows that amines, such as EAE, having a balanced interaction with water and glycol ether (exhibiting small immiscible region) are potential candidates for amine + water + glycol ether based phase separation solvent for CO2 capture.

DOI： 10.1016/j.jtice.2021.11.010

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

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

FUEL PROCESSING TECHNOLOGY 226 巻 2022年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL 114 巻 2022年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

JOURNAL OF MOLECULAR LIQUIDS 346 巻 2022年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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 CO<sub>2</sub> Methanation (Sabatier Reaction) over Ni/ZrO<sub>2</sub> at a Stoichiometric Feed-Gas Composition under Elevated Pressure

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

ENERGY & FUELS 35 巻 ( 24 ) 頁： 20216 - 20223 2021年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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 CO<sub>2</sub> Capture with a Pressure Swing Amine Process Driven by Cryogenic Pumping with the Unused Cold Energy of Liquefied Natural Gas

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

ACS SUSTAINABLE CHEMISTRY & ENGINEERING 9 巻 ( 47 ) 頁： 15908 - 15914 2021年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

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

AICHE JOURNAL 67 巻 ( 10 ) 2021年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Towards design of phase separation solvent for CO<sub>2</sub> capture using COSMO-SAC model

Hung, YC; Hsieh, CM; Machida, H; Lin, ST; Shimoyama, Y

JOURNAL OF MOLECULAR LIQUIDS 336 巻 2021年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

There is a growing interest in developing CO2 capture processes based on phase separation solvents due to its much lower energy consumption compared to the reference amine process using monoethanolamine (MEA). In this work, the predictive COSMO-SAC activity coefficient model was applied to describe phase behavior for phase separation solvent composed of amine + water + glycol ether. From the calculated ternary liquid-liquid equilibrium (LLE) phase diagram, ternary mixtures of fourteen selected amines + water + glycol ether can be classified into miscible- or immiscible-type solvents. The work presented here indicates that amines having comparable affinity to water and glycol ether generally result in a smaller two-phase region and form type I phase behavior near the amine-lean region. The amines having a strong affinity to water or glycol ether show a larger two-phase region and result in type II phase behavior. Further analysis shows that KOW and σ-profile can be good indicators for the affinity of amine to water and glycol ether, which is the key factor to determine the phase behavior of investigated ternary mixtures. The feed composition and operating temperature of phase separation solvent should be judged by the interaction between solvent molecules. This study demonstrates that COSMO-SAC is a useful tool for exploiting the phase behavior of potential phase separation solvents with limited available experimental data.

DOI： 10.1016/j.molliq.2021.116229

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

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

JOURNAL OF CHEMICAL AND ENGINEERING DATA 66 巻 ( 8 ) 頁： 3057 - 3071 2021年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS 156 巻 2021年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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, C; Adachi, N; Zhang, W; Machida, H; Hayashi, J; Watanabe, H; Norinaga, K

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 54 巻 ( 6 ) 頁： 334 - 343 2021年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Chemical Engineering of Japan

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 was proposed. A detailed chemical kinetic model was 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 together with the flow direction of the reductor, were revealed using an extended detailed chemical kinetic model involving 202 species, 1351 gas-phase reactions, and 101 surface reactions for soot formation and growth. The simulation revealed that near-complete decomposition of tar regarded as a set of all aromatic hydrocarbons is likely to require operation temperature of the reductor at temperatures as high as 1200°C, when the combustor is operated at 1800°C.

DOI： 10.1252/jcej.20we171

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

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

ENERGY & FUELS 35 巻 ( 7 ) 頁： 5479 - 5494 2021年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

Lin Y.

Chemical Engineering Science 229 巻 2021年1月

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

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

CARBON RESOURCES CONVERSION 4 巻頁： 219 - 229 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

CARBON RESOURCES CONVERSION 4 巻頁： 111 - 121 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Evaluation CO<inf>2</inf> solubility in biphasic solvent with AMP/Ether/Water for CO<inf>2</inf> capture

Esaki T., Ueno Y., Uchiyama H., Matsukuma Y., Machida H.

Proceedings of the International Conference on Power Engineering 2021, ICOPE 2021 2021年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of the International Conference on Power Engineering 2021, ICOPE 2021

We suggest new CO2 absorption processes with biphasic phase separation type for reducing consumption energy. the CO2-rich solution liquid was separated hydrophilic liquid and hydrophobic liquid. In this work, we studied some kind of amine and ether mixture solvents, and observed phase separation phenomena. From the results of phase separation characteristics, we selected with 2-Amino-2-methyl-1-prophanol (AMP), diethylene diethyl ether (DEGDEE) and water pair. We measured the CO2 solubility at different temperature and CO2 patricidal pressure conditions, and evaluated the effect of component concentration in the solvents on CO2 absorption characteristics and phase separation phenomena. We adjusted the biphasic solvents. AMP, DEGDEE and H2O of biphasic solvent weight-composition ratio are 30, 20 and 50 wt% respectively. The CO2 solubility of absorption at 40 ℃, 0.1atm was obtained 0.647 mol-CO2/mol-AMINE. The CO2 solubility of desorption at 90℃, 1.0 atm was obtained 0.177 mol-CO2/mol-AMINE. The difference of CO2 loading of this solvent was high performance of CO2 capture compared with that of other solvents. These result is attributed to the additive phase assisting in the regeneration of CO2 by extracting the regenerated amine. The results of the present study show reduction of desorption temperature and high CO2 absorption performance.

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

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

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

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

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

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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.

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

Nakaoka Mana, Tran Khuyen V. B., Yanase Keiichi, Machida Hiroshi, Norinaga Koyo

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 59 巻 ( 42 ) 頁： 19020-19029 2020年10月

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

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

Journal of Advanced Manufacturing and Processing 2 巻 ( 4 ) 頁： 1 - 12 2020年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

Machida Hiroshi, Esaki Takehiro, Yamaguchi Tsuyoshi, Norinaga Koyo

ACS SUSTAINABLE CHEMISTRY & ENGINEERING 8 巻 ( 23 ) 頁： 8732-8740 2020年6月

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

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

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 59 巻 ( 8 ) 頁： 3475-3484 2020年2月

Computational fluid dynamics simulation of CO<inf>2</inf> methanation in a shell-and-tube reactor with multi-region conjugate heat transfer

Zhang W.

Chemical Engineering Science 211 巻 2020年1月

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

Esaki T., Machida H., Norinaga K.

Journal of Advanced Manufacturing and Processing 2 巻 ( 1 ) 頁： 1 - 7 2020年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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

Machida H.

Journal of Molecular Liquids 292 巻 2019年10月

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

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

ISIJ INTERNATIONAL 59 巻 ( 8 ) 頁： 1376-1381 2019年

An approach for quantifying transferable hydrogen in pyrolyzing coals

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年

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

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年

Low temperature swing process for CO<sub>2</sub> absorption-desorption using phase separation CO<sub>2</sub> capture solvent

Machida, H; Ando, R; Esaki, T; Yamaguchi, T; Horizoe, H; Kishimoto, A; Akiyama, K; Nishimura, M

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL 75 巻頁： 1 - 7 2018年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Greenhouse Gas Control

We have developed a phase separation solvent which transforms into two liquid phases after CO2 absorption, in order to establish an energy-saving CO2 capture process. The CO2 loading changes strongly with temperature increase during the phase separation, which enables us to reduce the temperature difference between absorber and desorber. The low temperature swing process economizes the energy requirement for the CO2 capture process with highly-effective reaction-heat recovery. We evaluated the energy consumption of the CO2 capture process with our novel phase separation solvent based on the CO2 solubility. The energy requirement was estimated to be as low as 1.6 GJ/ton-CO2.

DOI： 10.1016/j.ijggc.2018.05.010

Shear Viscosity and Heterogeneous Structure of Alkylaminoethanol-Based CO2 Absorbents

Yamaguchi Tsuyoshi, Ando Ryuya, Yoshida Koji, Yamaguchi Toshio, Machida Hiroshi

JOURNAL OF PHYSICAL CHEMISTRY B 122 巻 ( 14 ) 頁： 4045-4050 2018年4月

Degradation Test for Energy-Saving CO<inf>2</inf> Absorbent based on Phase Separation Type Solvent by Aqueous (Amine + Ether) Solution

Maeda N., Kishimoto A., Machida H., Yamaguchi T.

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

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：GHGT 2018 - 14th International Conference on Greenhouse Gas Control Technologies

The unique phase separation type amine/ether absorbent is expected to realize the CO2 separation process with low-energy consumption (1.5GJ/ton-CO2). In this study, a degradation test of the absorbent under thermal load of liquid regeneration was conducted in order to clarify 1) the behavior of its performance declination for CO2 capture and 2) the behavior of amine loss mainly caused by generation of by-product. The regeneration condition was chosen based on two assumptions that a) most likely to damage to the solution, which means high-oxidation atmosphere containing oxygen and sulfur oxide, and b) adopting actual operating temperature when absorbing or desorbing. As a result, only a small amount of the CO2 capture capability was lost through 48 hours cyclic thermal load of 50-90 °C. Consequently, it was found that the phase separation type solvent could be durable enough for the practical use. Besides, the running cost associated with make-up amine might be drastically reduced.

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

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年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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.

Development of phase separation solvent for CO2 capture by aqueous (amine plus ether) solution

Machida Hiroshi, Oba Kazuki, Tomikawa Takashi, Esaki Takehiro, Yamaguchi Tsuyoshi, Horizoe Hirotoshi

JOURNAL OF CHEMICAL THERMODYNAMICS 113 巻頁： 64-70 2017年10月

過酸化水素の予熱条件が流通式メタン水熱部分酸化改質反応に与える影響査読有り

織田耕彦, 町田洋, 堀添浩俊

化学工学論文集 43 巻 ( 5 ) 頁： 342-346 2017年9月

Partial Oxidation of Methane by Fenton Reaction under Hydrothermal Environment 査読有り

Yasuhiko ORITA, Hiroshi MACHIDA, Hirotoshi HORIZOE

Journal of the Japan Institute of Energy 96 巻 ( 8 ) 頁： 339-345 2017年8月

Phase Separation Solvent for CO2 Capture 査読有り

Hiroshi Machida, Takehiro Esaki, Kazuki Oba, Takashi Tomikawa, Tsuyoshi Yamaguchi, Hirotoshi Horizoe

Energy Procedia 114 巻頁： 823-826 2017年7月

Effect of Preheating Conditions of Hydrogen Peroxide on Flow-Type Hydrothermal Partial Oxidation of Methane

Orita Yasuhiko, Machida Hiroshi, Horizoe Hirotoshi

KAGAKU KOGAKU RONBUNSHU 43 巻 ( 5 ) 頁： 342-346 2017年

Biomass Pretreatment with Hydrothermal Explosion for Bioethanol Production 査読有り

Machida, Hiroshi Honda, Yurie Saito, Masahiro Horizoe, Hirotoshi

96 巻 ( 9 ) 頁： 386-392 2017年

Hydrogen Peroxide and Carbon Dioxide Effect on Biomass Hydrothermal Treatment 査読有り

Hiroshi MACHIDA, Masahiro SAITO, and Hirotoshi HORIZOE

Journal of the Japan Institute of Energy 95 巻 ( 639 ) 頁： 644 2016年

Modeling of CO2 Solubility in Tertiary Amine Solvents Using pKa 査読有り

Hiroshi Machida, Hidetaka Yamada, Shin Yamamoto

Journal of Chemical & Engineering Data 61 巻頁： 2144-2148 2016年

CO2 Solubility Measurements and Modeling for Tertiary Diamines 査読有り

Hiroshi Machida, Hidetaka Yamada, Yuichi Fujioka, Shin Yamamoto

Journal of Chemical & Engineering Data 60 巻頁： 814 2015年

High efficiency metal removal from hexane-extracted algae oil using super and subcritical propane 査読有り

Hiroshi Machida, Hirotoshi Horizoe

Energy Conversion and Management 95 巻頁： 90 2015年

High pressure vapor liquid equilibria measurements and modeling of butane ethanol system and isobutane ethanol system 査読有り

H. Machida, K. Matsumura, H. Horizoe

Fluid Phase Equilibria 375 巻頁： 176-180 2014年5月

Production of 5-hydroxymethylfurfural from corn stalk catalyzed by corn stalk-derived carbonaceous solid acid catalyst 査読有り

Lulu Yan, Nian Liu, Yu Wang, Hiroshi Machida, Xinhua Qi

Bioresource Technology 173 巻頁： 462 2014年

Development of chemical CO2 solvent for high-pressure CO2 capture 査読有り

Shin Yamamoto, Hiroshi Machida, Yuichi Fujioka, Takayuki Higashii

Energy Procedia 37 巻頁： 505-517 2013年

Green chemical processes with supercritical fluids: Properties, materials, separations and energy 査読有り

Hiroshi Machida, Masafumi Takesue, Richard L. Smith Jr.

The Journal of Supercritical Fluids 60 巻 ( SI ) 頁： 2-15 2011年12月

Correlation of supercritical CO2-ionic liquid vapor-liquid equilibria with the e*-modified Sanchez-Lacombe equation of state 査読有り

Masayuki Iguchi, Hiroshi Machida, Yoshiyuki Sato and Richard L. Smith, Jr.

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING 7 巻頁： S95-S100 2011年10月

Infinite dilution partition coefficients of benzene derivative compounds in supercritical carbon dioxide + ionic liquid systems: 1-butyl-3-methylimidazolium chloride [bmim][Cl], 1-butyl-3-methylimidazolium acetate [bmim][Ac] and 1-butyl-3-methylimidazolium octylsulfate [bmim][OcSO4] 査読有り

Yuya Hiraga, Wataru Endo, Hiroshi Machida, Yoshiyuki Sato, Taku Michael Aida, Masaru Watanabe, Richard L. Smith Jr.

The Journal of Supercritical Fluids 2011年8月

Simple modification of the temperature dependence of the Sanchez-Lacombe equation of state 査読有り

Hiroshi Machida, Yoshiyuki Sato, Richard L. Smith Jr.

Fluid Phase Equilibria 297 巻 ( 2 ) 頁： 25 2010年10月

Ionic liquid structural effects on solute partitioning in biphasic ionic liquid and supercritical carbon dioxide systems 査読有り

Hiroshi Machida, Toru Kawasumi, Wataru Endo, Yoshiyuki Sato, Richard L. Smith Jr.

Fluid Phase Equilibria 294 巻 ( 1-2 ) 頁： 15 2010年7月

Measurement and correlation of high pressure densities of ionic liquids, 1-ethyl- 3-methylimidazolium L-lactate ([emim][Lactate]), 2-hydroxyethyl-trimethylammonium L-lactate ([(C2H4OH)(CH3)3N][Lactate]), and 1-butyl-3- methylimidazolium chloride ([bmim][Cl]) 査読有り

Hiroshi Machida, Ryosuke Taguchi, Yoshiyuki Sato and Richard L. Smith, Jr.

Journal of Chemical & Engineering Data 56 巻 ( 4 ) 頁： 923-928 2010年

Analysis of ionic liquid PVT behavior with a Modified Cell Model 査読有り

Hiroshi Machida, Ryosuke Taguchi, Yoshiyuki Sato, Richard L. Smith Jr.

Fluid Phase Equilibria 281 巻 ( 2 ) 頁： 25 2009年7月

High-Pressure Densities of 1-Alkyl-3-methylimidazolium Hexafluorophosphates and 1-Alkyl-3-methylimidazolium Tetrafluoroborates at Temperatures from (313 to 473) K and at Pressures up to 200 MPa 査読有り

Ryosuke Taguchi, Hiroshi Machida, Yoshiyuki Sato and Richard L. Smith, Jr.

Journal of Chemical & Engineering Data 54 巻 ( 1 ) 頁： 22 2009年

Measurement and correlation of supercritical CO2 and ionic liquid systems for design of advanced unit operations 査読有り

Hiroshi Machida, Ryosuke Taguchi, Yoshiyuki Sato, Louw J. Flourusse, Cor J. Peters, Richard L. Smith, Jr.

Frontiers of Chemical Engineering in China 3 巻 ( 1 ) 頁： 12 2009年

Pressure-volume-temperature (PVT) measurements of ionic liquids ([bmim+][PF6 -], [bmim+][BF4 -], [bmim+][OcSO4 -]) and analysis with the Sanchez-Lacombe equation of state 査読有り

Hiroshi Machida, Yoshiyuki Sato, Richard L. Smith Jr.

Fluid Phase Equilibria 264 巻 ( 1-2 ) 頁： 1 2008年3月

Measurement and correlation of infinite dilution partition coefficients of aromatic compounds in the ionic liquid 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6])-CO2 system at temperatures from 313 to 353 K and at pressures up to 16 MPa 査読有り

Hiroshi Machida, Yoshiyuki Sato, Richard L. Smith Jr.

The Journal of Supercritical Fluids 43 巻 ( 3 ) 頁： 430 2008年

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