中国钢铁生产“碳中和”解决方案探讨

Discussion on solution of"carbon neutrality"in China's steel production

根据某工程各工序碳素流计算出全流程吨热轧钢材的直接CO_(2)排放量为1.786 t。以此为基数,就高炉-转炉长流程工艺的几种主要减碳技术的减碳效果进行了定量评估,发现减碳效果有限,只能作为从“碳达峰”到“碳中和”的过渡方案或最终解决方案的补充。从“碳中和”要求的角度看,以全废钢或气基还原铁+废钢为原料的电炉炼钢短流程无疑是最佳解决方案。结合中国资源条件就几种典型短流程组合方案进行了适应性分析,提出了以“氢基竖炉直接还原铁+电炉炼钢方案”为主、以“高炉-转炉长流程工艺减碳技术+碳捕集与封存(CCS)方案”和“全废钢电炉炼钢方案”为补充的“碳中和”解决方案,最后给出了安全低成本获取氢基竖炉直接还原铁所需的“绿氢”方案建议。

The directly emitted CO_(2) for per ton of hot-rolled steel products in the full process route of a project is 1.786 t which is calculated from the carbon flow of each process.With this value as basis,a quantitative evaluation is made on the carbon reduction result of several major carbon reduction technologies in the BF-BOF long process route,and the result revealed that the technologies can function only as a transition approach or a supplement to the final solution in the evolution course from"peak emission"to"carbon neutrality"due to their limited carbon reduction etfect.Viewing from the perspective of"carbon neutrality"requirements,the short process route of EAF with 100% scrap or gas-based DRI+scrap as raw materials,assuredly,is the best solution.An applicability analysis on portfolio solution of several typical short process routes which in consideration of China's resource conditions is made,and an all-round solution is proposed,which is underlaid by“H_(2)-based shaft furnace DRI+EAF steelmaking”and supplemented by“BF-BOF long process CO_(2) reduction technology+CCS route”and“100% scrap EAF steelmaking route”.A solution of obtaining the"green H_(2)"required for H_(2)-based shaft furnace DRI production is also suggested.