TY - JOUR
T1 - Numerical analysis of reaction degradation for threedimensional coke pore structure
AU - Numazawa, Yui
AU - Igawa, Daisuke
AU - Matsuo, Shohei
AU - Saito, Yasuhiro
AU - Matsushita, Yohsuke
AU - Aoki, Hideyuki
AU - Shishido, Takahiro
AU - Okuyama, Noriyuki
N1 - Funding Information:
This work was carried out as a part of the research activities “CO2 Ultimate Reduction in Steelmaking process by Innovative technology for cool Earth 50 (COURSE50). The financial support from New Energy and Industrial Technology Development Organization (NEDO) is gratefully acknowledged.
Publisher Copyright:
© 2018 ISIJ.
PY - 2018/8/15
Y1 - 2018/8/15
N2 - In order to investigate coke degradation behavior due to CO2 gasification reaction in the blast furnace, mass transfer analyses with the reaction and stress analyses for coke considering its structure after the reaction were performed. Using the finite element method, CO2 gas diffusion in a coke lump and consumption of coke matrices owing to the gasification reaction were considered for the coke model in which the actual coke structure was reproduced. The rate-controlling step was also evaluated calculating the Thiele modulus and the effectiveness factor of catalyst obtained from CO2 concentration distribution in a coke lump. Further, stress analyses assuming a uniaxial tensile test were carried out for the coke model after CO2 gasification reaction, and the effect of the gasification reaction on a stress state in a coke lump was investigated. As a result, the reaction progressed mainly in the vicinity of the external surface with reaction temperature of 1 673 K while it did uniformly in the whole coke lump with 1 273 and 1 473 K. Thus, the rate-controlling step shifted from the reaction-controlling step to the diffusion-controlling step with an increase in a reaction temperature, and the Thiele modulus and the effectiveness factor of catalyst also showed the same trend. From the stress analysis, coke strength decreased uniformly in the whole coke lump in case of the reaction-controlling step whereas it did mainly in the vicinity of the external surface in case of diffusion-controlling step.
AB - In order to investigate coke degradation behavior due to CO2 gasification reaction in the blast furnace, mass transfer analyses with the reaction and stress analyses for coke considering its structure after the reaction were performed. Using the finite element method, CO2 gas diffusion in a coke lump and consumption of coke matrices owing to the gasification reaction were considered for the coke model in which the actual coke structure was reproduced. The rate-controlling step was also evaluated calculating the Thiele modulus and the effectiveness factor of catalyst obtained from CO2 concentration distribution in a coke lump. Further, stress analyses assuming a uniaxial tensile test were carried out for the coke model after CO2 gasification reaction, and the effect of the gasification reaction on a stress state in a coke lump was investigated. As a result, the reaction progressed mainly in the vicinity of the external surface with reaction temperature of 1 673 K while it did uniformly in the whole coke lump with 1 273 and 1 473 K. Thus, the rate-controlling step shifted from the reaction-controlling step to the diffusion-controlling step with an increase in a reaction temperature, and the Thiele modulus and the effectiveness factor of catalyst also showed the same trend. From the stress analysis, coke strength decreased uniformly in the whole coke lump in case of the reaction-controlling step whereas it did mainly in the vicinity of the external surface in case of diffusion-controlling step.
KW - Coke degradation behavior
KW - Coke strength
KW - Controlling step
KW - Gasification
KW - Ironmaking
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U2 - 10.2355/isijinternational.ISIJINT-2018-144
DO - 10.2355/isijinternational.ISIJINT-2018-144
M3 - Article
AN - SCOPUS:85051481726
VL - 58
SP - 1420
EP - 1426
JO - Transactions of the Iron and Steel Institute of Japan
JF - Transactions of the Iron and Steel Institute of Japan
SN - 0915-1559
IS - 8
ER -