关于直接还原铁工艺及还原气制备的若干思考

优化改良氢基直接还原铁制备工艺是中国发展实施碳减排的有效途径之一,随着碳减排和碳中和的积极推进,氢基直接还原铁工艺必将有较大的发展.从含铁原料、还原气制备参数选择和能源保障等三方面讨论分析了有关氢基气体直接还原铁工艺中存在的难点问题,尤其针对还原气制备参数的选择问题,创新性地提出了确定制备氢基还原气体工艺参数的图解法....

Thoughts on preparation of hydrogen-based reduction gas and process of direct reduction iron

Optimizing and improving the preparation process of hydrogen based direct reduction iron is one of the effective ways to develop and implement carbon emission reduction in China. Therefore, hydrogen-based direct reduction iron process will have great development with the promotion of “carbon emission reduction” and “carbon neutralization”. This paper discussed and analyzed the difficult problems in the process of hydrogen-based gas direct reduction of iron from three aspects: iron containing raw materials, reduction gas preparation parameter selection and energy guarantee. Especially for the selection of reduction gas preparation parameters, an innovative graphical method for determining the process parameters of hydrogen-based reduction gas was proposed. This method was used to construct the "mass and chemical balance diagram of H-C-O system" and unify the expression of reducing gas by n_H/n_C and n_O/n_C. Through the introducing of ray nH₂O/nCH₄ scale passing through CO₂ point, the nCO₂/nCH₄ scale parallel to line L₁ (nH₂O+nCH₄>0、nCO₂=0), and the straight line family of nH₂/nCO isolines at different temperatures, and using " mass and chemical equilibrium diagram of H-C-O system", the existence domain of any composition gas could be clearly expressed, that means, the n_H/n_C and n_O/n_C of any composition gas could be clearly expressed. Using this method, the addition amount of nH₂O or nCO₂ or for 1 mol CH₄ under a given nH₂/nCO can be determined. For the process of preparing hydrogen-based reducing gas by reforming natural gas or coke oven gas, the process operating parameters (such as, addition amount and ratio) for preparing hydrogen-based reducing gas with a given nH₂/nCO at a specified temperature can be easily determined by graphical method according to the gas source conditions, so as to provide a theoretical guiding basis for the selection of process parameters for preparing hydrogen-based reducing gas.