煤直接制甲烷系统的热力学分析

Thermodynamic Analysis of Direct Methane Production From Coal

通过Ca基吸收剂的引入,将煤的气化反应、甲烷化反应和CO_2吸收反应集成在同一反应器内,形成煤直接制甲烷系统,可缩短传统煤制甲烷系统流程,提高转化效率。分析了热力学平衡状态下温度、压力、Ca/C比和H_2O/C比对气体产物产量的影响。结果表明降低反应温度和提高反应压力有利于甲烷的产生,而Ca/C比和H_2O/C比的选取存在最优值,得到了煤直接制甲烷体系较为适宜的反应条件为:500～700℃,5～10 MPa,Ca/C=0.5,H_2O/C=1。

By the introduction of Ca-based CO2 absorbent, a new system of direct methane production from coal was developed, which integrated coal gasification, methanation, and CO2 absorption in one reactor. Comparing to the traditional coal-to-methane process, it would have a shorter process and higher conversion efficiency. The effects of temperature, pressure, Ca/C ratio, and H20/C ratio were analyzed in thermodynamic equilibrium model. The results showed that, the CH4 yield increased with reducing temperature and increasing pressure, and the selection of Ca/C ratio and H20/C ratio has an optimal value. The suitable range of reaction conditions for direct methane production from coal were at about 500-700℃, 5-10 MPa, Ca/C=0.5, H20/C=I.