针对低浓度煤层气深冷液化工艺,使用化工流程模拟软件Aspen Plus,对低温精馏过程进行了模拟研究,发现当原料气入口流量为552 kmol/h,精馏塔压力为0．34 MPa时,塔底液态甲烷的纯度为99%。分析了抽采煤层气流量波动对低温精馏效果的影响,发现当煤层气流量降低时,塔顶氮氧尾气中的甲烷含量增加,并且处于爆炸界限内；随着煤层气流量增加,塔底甲烷的纯度和回收率均降低。%To aim at the cryogenic liquefaction technology of low-concentration coal-bed methane, simulation study was made on the cryogenic distillation process with Aspen Plus software. It was found from the study that when the inlet flow rate of the feed gas was 552 kmol/h and the pressure of the distillation column was 0. 34 MPa, the purity of the liquid methane at the column bottom was 99%. Analysis was carried out on the influence of the coal-bed methane flow rate fluctuations on the cryogenic distillation. When the flow rate of coal-bed methane decreased, the methane content in nitrogen oxide gases at the top of the column increased and was within the explosion limit;with the increase of the flow rate of coal-bed methane, the purity and recovery of the methane at the column bottom decreased.
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