窦明辉, 韩嘉伟, 孙洋, 孙章, 梁英华. Ca/Fe添加剂对焦炭在H2O+CO2气氛中溶损反应的影响[J]. 工程科学学报, 2023, 45(11): 1859-1867. DOI: 10.13374/j.issn2095-9389.2022.09.05.001
引用本文: 窦明辉, 韩嘉伟, 孙洋, 孙章, 梁英华. Ca/Fe添加剂对焦炭在H2O+CO2气氛中溶损反应的影响[J]. 工程科学学报, 2023, 45(11): 1859-1867. DOI: 10.13374/j.issn2095-9389.2022.09.05.001
DOU Minghui, HAN Jiawei, SUN Yang, SUN Zhang, LIANG Yinghua. Effect of Ca/Fe additives on solution loss reactions of cokes in H2O+CO2 atmosphere[J]. Chinese Journal of Engineering, 2023, 45(11): 1859-1867. DOI: 10.13374/j.issn2095-9389.2022.09.05.001
Citation: DOU Minghui, HAN Jiawei, SUN Yang, SUN Zhang, LIANG Yinghua. Effect of Ca/Fe additives on solution loss reactions of cokes in H2O+CO2 atmosphere[J]. Chinese Journal of Engineering, 2023, 45(11): 1859-1867. DOI: 10.13374/j.issn2095-9389.2022.09.05.001

Ca/Fe添加剂对焦炭在H2O+CO2气氛中溶损反应的影响

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

  • 摘要: 为了探究富氢高炉内Ca/Fe基高反应性焦炭的溶损反应特性,以CO2(N2)载带不同摩尔比例H2O蒸气(0~30%)进行焦炭溶损实验,通过分析尾气中CO和H2的含量,研究Ca/Fe添加剂对焦炭在H2O+CO2混合气氛下碳溶反应和水煤气反应的影响。研究表明,焦炭在H2O+CO2和H2O+N2两种气氛下的焦炭反应性随H2O蒸气载带率增加呈线性关系,焦炭在H2O+CO2气氛中溶损反应的拟合斜率k值明显小于在H2O+N2气氛中的k值,H2O+CO2混合气氛中H2O和CO2与焦炭反应存在竞争关系。而且基础焦炭(BC)反应性的实验与理论的差值明显小于Ca/Fe基焦炭(BC+Ca、BC+Fe)的差值,表明Ca/Fe添加剂影响了CO2和H2O与焦炭共同反应时的竞争关系。基于两种气氛下速率常数的差异提炼了两个抑制因子 \alpha_\rmCO_2/\rmH_2\rmO \alpha_\rmH_2\rmO/\rmCO_2 \alpha_\rmCO_2/\rmH_2\rmO 定量表征CO2对C+H2O反应的抑制程度, \alpha_\rmCO_2/\rmH_2\rmO 定量表征H2O对C+CO2反应的抑制程度,BC、BC+Fe、BC+Ca三种焦炭的 \alpha_\rmCO_2/\rmH_2\rmO 分别为0.260、0.251、0.170,而 \alpha_\rmH_2\rmO/\rmCO_2 分别为0.121、0.217、0.263,Ca/Fe添加剂降低了 \alpha_\rmCO_2/\rmH_2\rmO 而提高了 \alpha_\rmH_2\rmO/\rmCO_2 ,说明Ca/Fe添加剂能够减小CO2对C+H2O反应的抑制程度,显著增强C+H2O反应的活性。Ca/Fe基焦炭中催化活性物质为铁酸钙和硅铝酸钙,Ca/Fe元素在焦炭中赋存形式的不同导致了Ca/Fe添加剂对焦炭溶损反应催化效果的差异性。

     

    Abstract: 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, \alpha_\rmCO_2/\rmH_2\rmO and \alpha_\rmH_2\rmO/\rmCO_2 , 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 \alpha_\rmCO_2/\rmH_2\rmO could quantitatively characterize the inhibition degree of CO2 on C + H2O reaction in the H2O + CO2 atmosphere, and the inhibition factor \alpha_\rmH_2\rmO/\rmCO_2 could quantitatively characterize the inhibition degree of H2O on the C + CO2 reaction in the H2O + CO2 atmosphere. The \alpha_\rmCO_2/\rmH_2\rmO factors of BC, BC + Fe, and BC + Ca cokes are 0.260, 0.251, and 0.170, respectively, and the \alpha_\rmH_2\rmO/\rmCO_2 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 \alpha_\rmCO_2/\rmH_2\rmO factor and increase the \alpha_\rmH_2\rmO/\rmCO_2 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.

     

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