气基竖炉直接还原炼铁流程重构优化

直接还原铁比较纯净、成分稳定,是电炉炼钢的优质原料。中国焦化行业产生大量焦炉煤气,适宜发展以焦炉煤气为还原气的竖炉直接还原炼铁流程,现有工艺主要有Midrex工艺和HYL-ZR工艺。为了解决Midrex工艺和HYL-ZR工艺所存在的问题,通过流程功能分析,提出气基竖炉直接还原重构优化流程,主要工序包括焦炉煤气压缩、TSA预处理、PSA脱碳、PSA提纯CH₄、富氢气加热、竖炉直接还原炼铁等。该流程不仅净化焦炉煤气,而且可分离CH₄,使还原气中H₂与CO的比例达到8,并省去CH₄重整环节,提高炉内直接还原效率。该流程前端与焦化工序连接,后端与电弧炉连接,不仅有利于钢铁联合企业资源优化配置,而且可以生产天然气,提高能源利用效率。

Reconstruction optimization of gas-based shaft furnace direct reduction ironmaking process

Direct reduction iron (DRI) is a good raw material of electric arc furnace (EAF) steelmaking, which is purity and stable in chemical composition. The coking industry generates large quantities of coke oven gas (COG), which is suitable for the development of shaft furnace direct reduction ironmaking process with COG and the main processes are Midrex process and HYL-ZR process. In order to resolve the problems of Midrex process and HYL-ZR process, through process function analysis, the reconstruction optimization process of gas-based shaft furnace direct reduction ironmaking is proposed through the process function analysis. The main procedures include COG compression, TSA pretreatment, PSA decarbonization, PSA purification of CH₄, hydrogen-rich gas heating, shaft furnace direct reduction ironmaking, and so on. The process can improve the reduction efficiency of shaft furnace because the COG purification is achieved, CH₄ is separated, the ratio of H₂ and CO reaches to 8 in the reduction gas, and the CH₄ reforming is omitted. The process links the coking process and EAF, which is not only beneficial to the resource optimization of the integrated iron and steel works, but also can produce natural gas and improve energy utilization efficiency.