二氧化碳和水蒸气重整制甲醇的热力学分析

Thermodynamic analysis of CO_2-H_2O reforming for methanol production

二氧化碳和水蒸气重整制甲醇是有效利用二氧化碳资源的重要途径,具有重要的经济和环保意义。从热力学角度进行分析,找出合理的反应条件,以提高甲醇的选择性和收率,对指导CO2和H2O反应具有重要意义。文中基于Gibbs最小自由能原理对该体系的热力学平衡进行了相关计算,分析了温度、压力、原料配比H2O/CO2等条件对该反应体系平衡组成的影响。结果表明:改变温度对体系的平衡组成影响不大,而体系的平衡组成随着压力和原料配比H2O/CO2的增大而增大。得到优化反应条件为初始原料摩尔比n(H2O)/n(CO2)为7∶3,温度约为500 K,压力为8 MPa。这对二氧化碳水蒸气重整制甲醇反应条件的优化具有一定的指导价值。

CO2 -H2O reforming for methanol production is a promising way for effective use of CO2, which is challenging from both economic and environmental view points. It is of significance to make a thermodynamic analysis for CO2 -H2O reforming system, so as to find out the reasonable reaction conditions and improve the selectivity and yield of methanol. Based on the principle of minimum Gibbs free energy, thermodynamic equilibrium calculation was carried out to CO2 -H2O reforming system. The influence of the factors （ temperature, pressure and raw material ratio, etc） on the equilibrium composition of the reaction system was analyzed. The results show that the temperature has little impact on the equilibrium composition; the equilibrium composition of the system increases with the increase of pressure and H2O/CO2 molar ratio. The appropriate reaction conditions are H2O/CO2 molar ratio of 7 ： 3, the system temperature about 500 K and the pressure 8 MPa. This study provides a powerful theoretical support to optimize reaction conditions of CO2 -H2O reforming.