在负载镍催化剂上由甲烷和CO_2分步制取合成气的研究

Study of stepwise syngas production from methane and carbon dioxide on supported nickel catalyst

用热重分析法考察了在镍催化剂上通过甲烷积炭和ＣＯ２消炭（简称两步法）制合成气的可能性，得到积炭和消炭的过程机理及若干动力学参数。结果表明，在反应条件下，甲烷积炭反应活化能为７４．５ｋＪ／ｍｏｌ，主要积炭形式是须状炭，控制步骤是甲烷在镍催化剂上的表面反应；ＣＯ２消炭反应的活化能是１２６．６ｋＪ／ｍｏｌ，控制步骤是ＣＯ２与碳的表面反应，消炭过程的关键是碳与镍晶粒的紧密接触。积炭反应与消炭反应的速率，在一定实验条件（８７３Ｋ左右）下可以相互匹配。通过分析得到两步法制取合成气的操作是可行的。

Using dynamic thermogravimetry technique, the possibility of producing synthetic gas by means of carbon deposition by methanecracking and carbon elimination by carbondioxide (briefly referred to as two stepmethod) on nickel catalyst has been investigated. The process mechanism for carbon deposition and carbon elimination and various kinetics parameters have been obtained.' The result show that the activation energy of carbondeposition is 74. 5 kJ/mol with the main formof filamentous carbon and the rate controllingstep is the surface reaction of methane overthe catalyst. The activation energy of carbonelimination is 126. 6kJ/mol and the rate controlling step is the surface reaction betweenCO2 and carbon. The key issue of carbon elimination is the close contact between carbon and' nickel crystal grain. The both rates can bematching each other under a certain experimental condition (at 873K). It is feasible toproducing syngas by the two step method.