关于天然气重整制备富氢还原气体过程中析碳问题的调控--H-C-O体系质量及化学平衡衡算图的应用例  

Regulation of carbon deposition during preparation process of hydrogen-rich reducing gas by natural gas reforming--An application example of H-C-O system mass balance and chemical equilibrium diagram

作　　者：沈峰满 章苇玲 郑艾军[3] 郑海燕 丁智敏 李季 SHEN Fengman;ZHANG Weiling;ZHENG Aijun;ZHENG Haiyan;DING Zhimin;LI Ji(School of Metallurgy,Northeastern University,Shenyang 110819,Liaoning,China;Department of Technical Management,Baosteel Zhanjiang Iron and Steel Co.,Ltd.,Zhanjiang 524072,Guangdong,China;Xuanhua Iron and Steel Group Co.,Ltd.,HBIS,Xuanhua 075100,Hebei,China)

机构地区：[1]东北大学冶金学院,辽宁沈阳110819 [2]宝钢湛江钢铁有限公司制造管理部,广东湛江524072 [3]河钢集团宣化钢铁集团有限责任公司,河北宣化075100

出　　处：《钢铁》2023年第7期9-16,共8页Iron and Steel

基　　金：国家自然科学基金资助项目(NSFC52274322,NSFC51974073)。

摘　　要：采用天然气重整或焦炉煤气重整工艺制备富氢还原气体时,若操作参数控制不当将会出现碳的析出问题,影响制备富氢气体工序的稳定顺行,因此研究控制制备富氢还原气体过程中的析碳非常必要。应用“H-C-O体系质量及化学平衡衡算图”和化学平衡原理,探讨了天然气重整或焦炉煤气重整工艺制备富氢还原气体过程中的“析碳”问题。在假设天然气重整或焦炉煤气重整体系处于临界析碳状态的前提下,确定了析碳曲线与还原气体n_(H_(2))/n_(CO)、重整温度和体系总压等因素的对应关系,从热力学角度给出了天然气重整或焦炉煤气重整制备富氢还原气体工艺中的临界析碳曲线、“析碳区”与“非析碳区”以及控制析碳且能满足直接还原铁要求的给定n_(H_(2))/n_(CO)值富氢还原气体制备时的重整温度与体系总压等工艺参数。结果表明,为了确保n_(H_(2))/n_(CO)和有效成分φ(H_(2))+φ(CO)合量同时满足直接还原气体组成要求,在体系总压P_(tot)=0.1 MPa条件下重整温度须高于800℃;随着体系总压的升高,CH4的转化率呈下降趋势;对于低n_(H_(2))/n_(CO)(=2),随着体系总压的升高析碳区域将增大;但对于n_(H_(2))/n_(CO)(=5),随着体系总压的升高析碳区域反而变小,这是因为当n_(H_(2))/n_(CO)较低时,碳的气化反应为主流反应,提高压力将增强析碳,而当n_(H_(2))/n_(CO)较高时,甲烷分解反应为主流反应,压力升高将妨碍甲烷分解,抑制了析碳的缘故;另外,体系总压过高将无法获得有效成分φ(H_(2))+φ(CO)合量满足直接还原铁工艺要求的还原气体。If the operating parameters in the process of preparing hydrogen-rich reducing gas are not properly controlled,the problem of carbon deposition will occur,which will affect the stability of the process of preparing hydrogen-rich reducing gas by using natural gas or coke oven gas as the gas source.Therefore,it is necessary to investigate and control the problem of carbon deposition in the process of preparing hydrogen-rich reducing gas that meets the requirements of the direct reduction iron process.The problem of"carbon deposition"in the process of preparing hydrogen-rich reducing gas from natural gas reforming or coke oven gas reforming process was discussed by using the"H-C-O system mass and chemical balance diagram"and the principle of chemical equilibrium.Assuming that the natural gas reforming or coke oven gas reforming system is at the critical state of carbon deposition,the relationships between the carbon deposition curve and the factors of n_(H_(2))/n_(CO) of the reduction gas,reforming temperature,and total system pressure were determined,the critical carbon deposition curve in the process of reforming natural gas or coke oven gas to hydrogen-rich reducing gas was given from the perspective of thermodynamics,the"carbon deposition region"and"non-carbon deposition region"were obtained,and the process parameters,such as the reforming temperature of hydrogen-rich reducing gas and the total system pressure,which can inhibit the carbon deposition and meet the required n_(H_(2))/n_(CO) of direct reduction iron,were given.The results show that in order to ensure n_(H_(2))/n_(CO) and the total amount of the effective composition ofφ(H_(2))+φ(CO)simultaneously meet the requirements for the composition of the direct reduction gas,the reforming temperature must be higher than 800℃under P_(tot)=0.1 MPa;The conversion of CH4 decreased with the increase of total system pressure;For low n_(H_(2))/n_(CO)(=2),the carbon deposition region will increase with the increase of the total system pressure and for n_(H_(2))/n

关 键 词：富氢直接还原铁 富氢还原气体 天然气重整或焦炉煤气重整 H-C-O体系质量及化学平衡衡算图 析碳控制 热力学分析 

分 类 号：TF55[冶金工程—钢铁冶金]