2021/06/30 更新

写真a

チェ チョルヨン
CHOI Cheolyong
CHOI Cheolyong
所属
名古屋大学 大学院工学研究科 化学システム工学専攻 先進化学工学システム 特任助教
職名
特任助教

学位 1

  1. 博士(工学) ( 2019年3月   九州大学 ) 

 

論文 11

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

    Lin Yixiong, Yang Chen, Choi Cheolyong, Zhang Wei, Fukumoto Kazui, Machida Hiroshi, Norinaga Koyo

    AICHE JOURNAL     2021年6月

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    記述言語:日本語   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

    Web of Science

    Scopus

  2. Production of light hydrocarbons from organosolv lignin through catalytic hydrogenation and subsequent fast pyrolysis

    Zhang L., Choi C., Machida H., Norinaga K.

    Journal of Analytical and Applied Pyrolysis   156 巻   2021年6月

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    記述言語:日本語   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

    Scopus

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

    Choi Cheolyong, Zhang Wei, Fukumoto Kazui, Machida Hiroshi, Norinaga Koyo

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

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    記述言語:日本語   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

    Web of Science

    Scopus

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

    Lin Yixiong, Yang Chen, Choi Cheolyong, Zhang Wei, Machida Hiroshi, Norinaga Koyo

    CHEMICAL ENGINEERING SCIENCE   229 巻   2021年1月

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    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:Chemical Engineering Science  

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

    DOI: 10.1016/j.ces.2020.116105

    Web of Science

    Scopus

  5. A comprehensive study on butanolysis of furfuryl alcohol to butyl levulinate using tungstated zirconia and sulfonated carbon catalysts

    Thuppati U.R., Choi C., Machida H., Norinaga K.

    Carbon Resources Conversion   4 巻   頁: 111 - 121   2021年1月

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    記述言語:日本語   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

    Scopus

  6. 2-14 触媒層温度及びガス組成分布を考慮した解析によるメタネーション反応速度モデルの検討

    CHOI Cheolyong, 安田 将也, ZHANG Wei, 町田 洋, 則永 行庸

    石炭科学会議発表論文集   57 巻 ( 0 ) 頁: 44-45   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    <p>CO<sub>2</sub> methanation is expected to be an option for energy storage and supply integrated with water electrolysis using renewable energies, named power-to-gas, taking advantages of the applicability to the existing infrastructures for natural gas. There are only a few industrial-scale plants, and development of a kinetic model is essential for scaling up the methanation reactor. In this study, a kinetic model was developed for CO<sub>2</sub> methanation under three pressure conditions considered in industrial-scale plants. The rate coefficients were determined at each pressure and correlated with the total pressure. The derived model was applied to an estimation of a larger bench-scale reactor filled with a pelletized catalyst through one-dimensional packed bed simulations, in which the diffusion resistance caused by the use of the pellet was considered using a catalyst effectiveness factor. The kinetic model was able to reproduce the CO<sub>2 </sub>conversion at the exit and the temperature distribution in the catalyst bed. It revealed that formation of a side product, CO was suppressed at the entire range of reactor.</p>

    DOI: 10.20550/jiesekitanronbun.57.0_44

    CiNii Article

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

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

    Carbon Resources Conversion   2 巻 ( 1 ) 頁: 13 - 22   2019年4月

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    記述言語:日本語   出版者・発行元:Carbon Resources Conversion  

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

    DOI: 10.1016/j.crcon.2018.09.002

    Scopus

  8. Continuous monitoring of char surface activity toward benzene

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

    Carbon Resources Conversion   2 巻 ( 1 ) 頁: 43 - 50   2019年4月

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    記述言語:日本語   出版者・発行元:Carbon Resources Conversion  

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

    DOI: 10.1016/j.crcon.2018.12.001

    Scopus

  9. 1-2-2 石炭ガス化炉内硫黄化合物転換特性の詳細化学反応速度モデルに基づく解析

    安達 希美, Choi Cheolyong, ZHANG Wei, 町田 洋, 則永 行庸

    日本エネルギー学会大会講演要旨集   28 巻 ( 0 ) 頁: 10-11   2019年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    <p>Toward developing an environmentally-friendly coal gasification process, a deeper understanding of chemistry and kinetics of reactions happening in a gasifier is of great importance. This work presents a numerical approach to predict conversion characteristics of sulfur compounds in a reductor of a two-stage entrained flow coal gasifier. A detailed chemical kinetic model consisting of 1951 reactions and 257 chemical species were used to calculate concentration profiles along with the reductor position at different gasification modes, temperature, and coal types. The sulfur compounds were mainly converted into H<sub>2</sub>S, whereas COS is a second major product at the reductor outlet and the formation is more enhanced at an O<sub>2</sub>/CO<sub>2</sub>-blowing mode than those at air-, and O<sub>2</sub>/H<sub>2</sub>O-blowing modes. The predicted total concentrations of H<sub>2</sub>S and COS are ranged between 400 and 800 ppm and agreed with the results obtained with an air-blowing 200 ton/day test coal gasification plant reported in the literature.</p>

    DOI: 10.20550/jietaikaiyoushi.28.0_10

    CiNii Article

  10. 2-5 詳細反応化学速度モデルを用いた噴流床石炭ガス化炉における芳香族炭化水素の改質およびスス生成シミュレーション

    CHOI Cheolyong, 安達 希美, 町田 洋, 則永 行庸

    石炭科学会議発表論文集   56 巻 ( 0 ) 頁: 56-57   2019年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    <p>Tar evolved from coal pyrolysis contains polycyclic aromatic hydrocarbons (PAHs) that grow to soot through further aromatization in parall el with its reforming during gasification. Understanding of the chemistry and kinetics in a gasifier is important for developing low-temperature gasification. This work focused on numerical simulation of PAH reforming and soot formation in various coal typ es and gasification modes. A detailed chemical kinetic model was used for simulating a reductor of a two stage entrained flow gasifier under the gas composition determined by combination of experimental molecular composition of coal and inorganic gas compo sition at chemical equilibrium. O<sub>2</sub>/CO<sub>2</sub>-and O<sub>2</sub> /H<sub>2</sub>O-blown modes significantly reduced the yield of PAHs and the formation of soot. Growth of soot particle was dominated by acetylene addition above 1300°C, while nucleation of soot precursors and PAH condensat ion became dominant at lower temperature.</p>

    DOI: 10.20550/jiesekitanronbun.56.0_56

    CiNii Article

  11. 1-22 石炭熱分解時の芳香族クラスター成長により発生する水素の転換反応機構

    福岡 鉄也, CHOI Cheolyong, 町田 洋, 則永 行庸

    石炭科学会議発表論文集   56 巻 ( 0 ) 頁: 44-45   2019年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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

    DOI: 10.20550/jiesekitanronbun.56.0_44

    CiNii Article

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