H_(2)O+CO_(2)气氛下焦炭的溶损行为及气孔结构演变  

Solution behavior and pore structure evolution of coke under H_(2)O+CO_(2) atmosphere

作　　者：韩嘉伟 窦明辉 吕叶飞 付佳旭 孙章 HAN Jiawei;DOU Minghui;LU Yefei;FU Jiaxu;SUN Zhang(College of Chemical Engineering,North China University of Science and Technology,Tangshan 063210,Hebei,China)

机构地区：[1]华北理工大学化学工程学院,河北唐山063210

出　　处：《中国冶金》2024年第8期29-37,共9页China Metallurgy

基　　金：国家自然科学基金资助项目(51874136)。

摘　　要：探究含水气氛下焦炭气孔结构的溶蚀演化规律对认识焦炭在富氢高炉内的溶损劣化行为具有重要意义。采用自制连续进水的焦炭反应性测定装置开展柱状焦炭在CO_(2)、N_(2)+20%H_(2)O和CO_(2)+20%H_(2)O气氛的溶损试验,运用图像分析法结合环形测试方式逐层检测焦炭剖面的气孔结构特征,在空间尺度上探究焦炭溶损过程中气孔结构的演化规律。研究结果表明,柱状焦炭在H_(2)O+CO_(2)气氛下溶损反应中气孔结构呈现“类锥形”演化,H_(2)O的存在使得焦炭气孔分布呈现出未侵蚀焦芯距离减小、溶损扩散深度减弱的特征。焦炭小气孔含量随反应深度增加呈二次线性增大,H_(2)O的存在使得拟合方程的通径减小,表明焦炭内外层气孔结构差异增大。基于焦炭气孔溶蚀的溶损层体积和反应性,提出碳素单位溶损体积比参数,定量表征溶损反应的扩散深度,H_(2)O的存在使得碳素单位溶损体积比减小24.4%,焦炭未侵蚀焦芯所占比例增加9.78%。因此,反应气氛中H_(2)O含量增加导致溶损反应主要集中于焦炭表面,水煤气反应使得焦炭深层反应减弱、缩核程度增强。研究结果可为加深认识富氢高炉内焦炭劣化行为、完善焦炭质量评价体系提供试验基础和理论依据。It is of great significance for investigating the corrosion and evolution of coke pore structures under HO+CO_(2) atmospheres to understand the solution-loss and degradation behaviors of cokes in hydrogen-rich blast furnace.The solution-loss experiments of columnar cokes in the CO_(2),N_(2)+20%H_(2)O,and CO_(2)+20%H_(2)O atmospheres were carried out by a homemade coke reactivity measurement device with continuous water inflow.The characteris-tics of pore structure distribution in coke profiles were layer-by-layer detected by image analysis method combined with circular testing mode,and the evolution of coke pore structures during solution-loss process was studied on a three-dimensional scale.The results show that the pore structures of the columnar coke present a"cone-like"evolu-tion during the solution-loss reactions of coke under H_(2)O+CO_(2) atmosphere.The H_(2)O in the reaction atmosphere could shorten the reaction depth to the uneroded core of coke with the similar characteristics of pore distribution and weaken the diffusion depth of coke in the solution-loss reaction.The content of small pores in coke has a quadratic linear relationship with the reaction depth,and the path of the fitting quadratic equation(d)is proposed to charac-terize the degree of solution-loss evolution for coke pore structures.The H_(2)O in the reaction atmosphere could lead to the decrease of the d value,which shows that the difference in pore structure between the inner and outer layers of coke increases.Moreover,the solution-loss volume ratio of carbon based on the solution-loss layer volume and re-activity of cokes is proposed to quantitatively characterize the diffusion depth of the coke in solution-loss reaction.The H_(2)O in the reaction atmosphere could reduce the solution-loss volume ratio of carbon by 24.4%,and the pro-portion of uneroded core in coke increases by 9.78%.Therefore,the increase of H_(2)O content in the reaction atmos-phere promotes the solution loss reactions on the surface of the coke,and water-gas reaction

关 键 词：焦炭 气孔结构 H_(2)O+CO_(2)气氛 溶损反应 未侵蚀焦芯 

分 类 号：TQ520.1[化学工程—煤化学工程]