煤制合成天然气中甲烷化过程的分析与计算

Analysis and Calculation of Methanation Unit in Process of Coal to Synthetic Natural Gas

合成气甲烷化是煤制合成天然气过程中的重要步骤.基于自制Ni/A12O3催化剂的合成气甲烷化评价结果,通过热力学分析、反应温升计算、多级绝热固定床的工艺分析、流程模拟和能量分析,计算和讨论了合成气甲烷化反应在热力学平衡限制和催化剂使用温度250～650℃限制下的适宜工艺条件.以最大化生产高压蒸汽为能量优化目标的前提下,最优方案是第1级反应器的出口温度处于催化剂使用温度上限,所产高压蒸汽热量占总反应热的83％;适当降低反应器出口温度、增产中低压蒸汽,可降低有效能损失;优选工艺方案的有效能利用率达到65.19％.

The methanation of syngas in the process of coal to synthetic natural gas was studied. The appropriate reaction conditions over a self-made Ni/Al203 catalyst with the thermodynamics equilibrium limitation and the catalyst temperature tolerance（250-650 ℃） were investigated by thermodynamics analysis, temperature rise calculation, reaction process simulation in an adiabatic fixed bed and energy analysis. For the maximization of the high pressure steam production, the outlet temperature of the first methanation reactor should be at the upper limit of the catalyst temperature tolerance, at which the heat quantity of the generated high pressure steam was 83% of the total reaction heat. The recovery efficiency of the available energy would reach 65.19% by increasing the generation of medium and low pressure steam and reducing the reactor outlet temperature.