Faculty Profiles - NORINAGA Koyo

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

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

AICHE JOURNAL Vol. 67 ( 10 ) 2021.10

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

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

DOI： 10.1002/aic.17304

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

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

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

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

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

DOI： 10.1021/acs.energyfuels.1c01429

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

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

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

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

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

DOI： 10.1021/acs.jced.1c00195

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

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

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS Vol. 156 2021.6

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

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

DOI： 10.1016/j.jaap.2021.105096

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

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

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

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

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

DOI： 10.1252/jcej.20we171

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

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

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

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

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

DOI： 10.1021/acs.energyfuels.0c04052

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

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

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

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

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

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

DOI： 10.1016/j.crcon.2021.09.001

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

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

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

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

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

DOI： 10.1016/j.crcon.2021.03.003

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

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

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

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

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

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

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

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

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

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

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

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

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

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

DOI： 10.20550/jiesekitanronbun.57.0_44

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

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

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

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

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

DOI： 10.20550/jiesekitanronbun.57.0_48

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

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

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

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

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

DOI： 10.1002/amp2.10067

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

Esaki T., Machida H., Norinaga K.

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

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

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

DOI： 10.1002/amp2.10033

1-12 Numerical simulation for a CO2 methanation reactor Reviewed

Zhang Wei, Mizoguchi Risa, Machida Hiroshi, Norinaga Koyo

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

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

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

DOI： 10.20550/jiesekitanronbun.56.0_24

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

CHOI Cheolyong, ADACHI Nozomi, MACHIDA Hiroshi, NORINAGA Koyo

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

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

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

DOI： 10.20550/jiesekitanronbun.56.0_56

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

FUKUOKA Tetsuya, CHOI Cheolyong, MACHIDA Hiroshi, NORINAGA Koyo

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

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

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

DOI： 10.20550/jiesekitanronbun.56.0_44

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

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

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

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

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

DOI： 10.20550/jiesekitanronbun.56.0_26

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

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

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

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

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

DOI： 10.20550/jietaikaiyoushi.28.0_10