适合于低浓度煤层气的低温液化精馏浓缩的工艺流程模拟与分析

Simulation and Analysis of Low-temperature Liquefaction and Distillation Process of Low-concentration CBM

针对大陆矿煤层气气源条件,提出了一种低浓度煤层气低温液化精馏分离的工艺流程。该方法中的液化系统采用混合制冷剂液化工艺,低温部分采用低温精馏的方法从LNG中分离氮氧,运用大型化工流程软件对液化系统进行了模拟计算与比较分析,分析了煤层气中O2含量的变化及精馏塔的再沸比的变化对LNG的组分的影响,以及再沸比的变化对再沸器热负荷的影响。

According to the characteristics of conditions in the Dalu mine gas source,the paper presents a cryogenic liquefaction and distillation separation process which is suitable for low concentration CBM containing plentiful nitrogen and oxygen.The liquefaction unit adopts highefficiency mixed refrigerant liquefaction cycle.The low-temperature part adopts the distillation tower to remove the nitrogen and oxygen from LNG.The low concentration CBM liquefaction system is simulated and analyzed using large-scale numerical analysis software.It analyzes the influence of O2 mole fraction in CBM,and the molar boil-up ratio on LNG components,such as CH4 and O2.It also analyzes the influence of the molar boil-up ratio on the distillation tower duty.