由CO和CO₂加氢制甲烷是现今氢能储存及燃料和化学品可持续生产的有效途径之一，但目前对该反应过程（尤其是针对CO和CO₂混合物加氢）的一些细节尚不明晰。为此，作为前期有关CO和CO₂加氢制烃和醇研究工作的补充，本工作对CO和CO₂，尤其是两者混合物的加氢制甲烷反应过程进行了热力学分析。结果证实，与单独CO或CO₂相比，两者混合物加氢制甲烷更为合适，总碳基甲烷收率可作为评估甲烷合成反应过程效率的重要指标。CO加氢的甲烷平衡收率比CO₂加氢的高，而CO和CO₂混合物加氢的总碳基甲烷平衡收率位于两者之间；对于CO和CO₂混合物加氢，尽管CO和CO₂的平衡转化率随进料组成不同会有很大的变化，但其总碳基甲烷平衡收率随着原料中CO₂/(CO+CO₂)物质的量比的增大而线形降低。整体上看，在温度低于400 ℃和压力高于0.1 MPa时，无论是CO、CO₂、还是两者混合物的化学计量比加氢，其总碳基甲烷平衡收率均高于85%。这些结果无疑对高效CO和CO₂加氢制甲烷催化剂研制及反应过程的设计和操作优化有重要的参考价值。

The synthesis of methane from CO and CO₂ by hydrogenation is now considered as a promising route in effectively storing hydrogen energy as well as sustainably producing fuels and chemicals, while many reaction details involved in such processes, in particular for the hydrogenation of the CO and CO₂ mixture, are not yet adequately understood. As a supplement to our previous works on the hydrogenation of CO and CO₂ into alcohols and hydrocarbons, a thermodynamic consideration is made in this work to evaluate the potential and limit for the synthesis of methane from CO, CO₂, and their mixture in particular. The results consolidate that in comparison with single CO or CO₂, their mixture is probably more credible in practice for the production of methane by hydrogenation, where the overall C-based methane yield can be used as the major index to evaluate the process efficiency. The hydrogenation of CO shows a higher equilibrium yield of methane than the hydrogenation of CO₂, while the overall C-based equilibrium yield of methane for the hydrogenation of the CO and CO₂ mixture just lies in between and decreases almost lineally with the increase of the CO₂/(CO+CO₂) molar ratio in the feed, despite the great change in the equilibrium conversions of CO and CO₂ with the feed composition. Nevertheless, an adequate overall C-based equilibrium yield of methane (> 85%) can be achieved at a temperature lower than 400 ℃ and a pressure higher than 0.1 MPa for the stoichiometric hydrogenation of CO, CO₂, or their mixture whichever. These results should be beneficial to the design of more efficient catalysts and processes for the hydrogenation of CO and CO₂ to methane.