TY - JOUR
T1 - Numerical simulation of single coal char particle combustion with the overall gas-phase reaction
AU - Ishimoda, Kengo
AU - Akaotsu, Shota
AU - Saito, Yasuhiro
AU - Matsushita, Yohsuke
AU - Aoki, Hideyuki
N1 - Funding Information:
The authors gratefully acknowledge financial support from the Japan Society for the Promotion of Science (KAKENHI 16K18354).
Publisher Copyright:
Copyright © 2019 Journal The Society of Chemical of Chemical Engineering Engineers, of Japan
PY - 2019
Y1 - 2019
N2 - The quasi-steady state heat and mass transfer around a single coal char particle with and without CO oxidation was numerically analyzed to investigate the effect of CO oxidation on the reaction process of char. With CO oxidation, the gas temperature around the particle is increased by the exothermic heat of CO oxidation, and the particle itself also experiences a temperature increase due to the heat transfer between high-temperature gas and the particle. In addition, the generation of additional CO2 by CO oxidation promotes the CO2 gasification of char, whereas the consumption of O2 suppresses the char oxidation. As a result of balancing among these factors, the net reaction rate of char, which is the sum of the partial oxidation rate and CO2 gasification rate, with CO oxidation became larger than that without CO oxidation. Under conditions of a higher temperature and larger particle size, the net reaction rate with CO oxidation was larger than that without CO oxidation, though the partial oxidation rate with CO oxidation was smaller than that without CO oxidation because of the promoted consumption of O2 by CO oxidation. This result indicates that CO2 gasification compensates for the decrease in the net reaction rate due to the suppression of char oxidation. Therefore, CO oxidation should greatly affect the heterogeneous reaction rates of char, especially CO2 gasification, through changes in the temperature and compositions of the gas-phase near a coal char particle.
AB - The quasi-steady state heat and mass transfer around a single coal char particle with and without CO oxidation was numerically analyzed to investigate the effect of CO oxidation on the reaction process of char. With CO oxidation, the gas temperature around the particle is increased by the exothermic heat of CO oxidation, and the particle itself also experiences a temperature increase due to the heat transfer between high-temperature gas and the particle. In addition, the generation of additional CO2 by CO oxidation promotes the CO2 gasification of char, whereas the consumption of O2 suppresses the char oxidation. As a result of balancing among these factors, the net reaction rate of char, which is the sum of the partial oxidation rate and CO2 gasification rate, with CO oxidation became larger than that without CO oxidation. Under conditions of a higher temperature and larger particle size, the net reaction rate with CO oxidation was larger than that without CO oxidation, though the partial oxidation rate with CO oxidation was smaller than that without CO oxidation because of the promoted consumption of O2 by CO oxidation. This result indicates that CO2 gasification compensates for the decrease in the net reaction rate due to the suppression of char oxidation. Therefore, CO oxidation should greatly affect the heterogeneous reaction rates of char, especially CO2 gasification, through changes in the temperature and compositions of the gas-phase near a coal char particle.
KW - CO Oxidation
KW - Heterogeneous Reaction
KW - Pulverized Coal Combustion
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U2 - 10.1252/jcej.18we012
DO - 10.1252/jcej.18we012
M3 - Article
AN - SCOPUS:85069697643
VL - 52
SP - 616
EP - 624
JO - Journal of Chemical Engineering of Japan
JF - Journal of Chemical Engineering of Japan
SN - 0021-9592
IS - 7
ER -