研究者詳細 - 町田　洋

論文 - 町田　洋

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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.

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