Effect of Ca/Fe additives on solution loss reactions of cokes in H2O+CO2 atmosphere

被引：0
|
作者：
Dou M. [1 ]
Han J. [1 ]
Sun Y. [1 ]
Sun Z. [1 ]
Liang Y. [1 ]
机构：
[1] College of Chemical Engineering, North China University of Science and Technology, Tangshan
来源：
Gongcheng Kexue Xuebao/Chinese Journal of Engineering | 2023年 / 45卷 / 11期
关键词：
Ca/Fe additives; catalysis; coke; H[!sub]2[!/sub]O + CO[!sub]2[!/sub] atmosphere; inhibition factor; solution loss reaction;
D O I：
10.13374/j.issn2095-9389.2022.09.05.001
中图分类号：
学科分类号：
摘要：
To examine the solution loss reaction properties of cokes with Ca/Fe additives in a hydrogen-rich blast furnace, the solution loss reactions of cokes were performed using a CO2 (N2) carrier gas with various percentages (0–30%) of H2O vapor, and the effect of Ca/Fe additives on the Boudouard reaction (C + CO2 = 2CO) and water–gas reaction (C + H2O = CO + H2) of cokes in a H2O + CO2 atmosphere was studied by examining the content of CO and H2 in the off-gas. The results demonstrate that the coke reactivity has a positive linear relationship with the percentages of H2O vapor in H2O + CO2 and H2O + N2 atmospheres, and the fitting slope k could be used to characterize the rate constant for the solution loss reaction of cokes in H2O + CO2 and H2O + N2 atmospheres. The k value for the solution loss reaction of the coke in the H2O + CO2 atmosphere is smaller than that of the coke in the H2O + N2 atmosphere, which shows that there is a competition between the reactions of H2O and CO2 with cokes in the H2O + CO2 atmosphere. Furthermore, the experimental reactivities of coke are smaller than their theoretical reactivities in the H2O + CO2 atmosphere, and the difference between the experimental and theoretical reactivities of the basic coke (BC) is less than those of the cokes with Ca/Fe additives (BC + Ca, BC + Fe), which shows that the Ca/Fe additives affect the competitive relationship of the reactions of CO2 and H2O with coke. Two inhibition factors, αCO2/H2O and αH2O/CO2 , are proposed to measure the degree of inhibition based on the difference in the k value for the cokes in H2O + CO2 and H2O + N2 atmospheres. The inhibition factor αCO2/H2O could quantitatively characterize the inhibition degree of CO2 on C + H2O reaction in the H2O + CO2 atmosphere, and the inhibition factor αH2O/CO2 could quantitatively characterize the inhibition degree of H2O on the C + CO2 reaction in the H2O + CO2 atmosphere. The αCO2/H2O factors of BC, BC + Fe, and BC + Ca cokes are 0.260, 0.251, and 0.170, respectively, and the αH2O/CO2 factors of BC, BC + Fe, and BC + Ca are 0.121, 0.217, and 0.263, respectively. The Ca/Fe additives in cokes reduce the αCO2/H2O factor and increase the αH2O/CO2 factor, showing that Ca/Fe additives can attenuate the inhibition degree of CO2 on the C + H2O reaction and improve the activity of the C + H2O reaction, and the Ca additive has a greater impact on the competitive relationship between the reactions of CO2 and H2O with coke than the Fe additive. The catalytically active substances in Ca/Fe additives in cokes could be CaFe2O4 and Ca2Al2SiO7, and the difference in the existing states of Ca/Fe elements in cokes causes the difference in the catalytic effect of Ca/Fe additives on the solution loss reactions of cokes. © 2023 Science Press. All rights reserved.
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页码：1859 / 1867
页数：8
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