二甲醚与合成气反应制乙醇的热力学计算与分析

Thermodynamics of ethanol synthesis from dimethyl ether and syngas

采用Benson基团贡献法估算得到二甲醚（DME）和乙酸甲酯（MA）的标准生成焓和标准生成吉布斯自由能，在298～1000K时计算了DME与合成气制乙醇（DME羰基化反应、MA加氢反应以及二者组成的总反应）过程中的反应焓变、反应熵变、反应吉布斯自由能变和化学反应的平衡常数。在此基础上，分析了反应压力、反应温度和原料比对DME转化率的影响。在413K、1＆#215;105Pa、CO∶DME=1条件下考察了不同H2浓度情况下合成乙醇反应中两个反应的协同效应。分析结果表明，在低于493K、3MPa、n（CO）∶n（DME）=1的条件下有利于合成反应的进行，由于两反应的协同效应，使MA加氢反应的平衡转化率有大幅度提高。

Both standard formation enthalpy and standard Gibbs free energy of dimethyl ether （DME） and methyl acetate were estimated with the Benson group contribution method. Reaction enthalpy change,reaction entropy change,reaction Gibbs free energy change and equilibrium constant of reactions of ethanol synthesis （DME carbonylation,MA hydrogenation,overall reactions） were calculated and analyzed. On this basis,effects of reaction temperature,reaction pressure,raw material ratio on DME conversion were investigated. The synergistic effect between the two reactions of ethanol synthesis were investigated at different concentrations of H2 under the conditions of 413K,normal pressure,CO∶DME=1. A moderate reaction temperature （lower than 493K）,3MPa,n（CO）∶n（DME）=1 were beneficial to ethanol synthesis and the equilibrium conversion in MA hydrogenation increased greatly due to this synergistic effect.