含氧煤层气脱氧制LNG工艺研发

Research of Oxygen-contained Coal-bed Methane to Produce LNG Through De-oxygenation

设计了一种利用氮-甲烷膨胀制冷低温精馏含氧煤层气制LNG的工艺,并对其进行了模拟分析。结果表明,该工艺可较彻底除去氮气、氧气等,获得较高浓度的LNG产品。同时分析了回流比、塔板数以及入塔温度对塔底产品含氧量和甲烷含量的影响,并且对该低温精馏工艺中的各设备进行了能耗分析。结果表明,在精馏塔进料温度为-163℃、压力为0.2 MPa时,最佳工艺操作条件为回流比1.5,塔板数24,在此条件下,甲烷回收率可达99.64%,塔底甲烷产品纯度高达99.98%,氧气体积分数仅为0.016%,系统单位能耗0.573 kWh/m3。

In order to better use the oxygencontained coalbed methane （CBM） extracted in the process of coal min ing, a kind of nitrogenmethane expansion refrigeration and low temperature distillation technology for purification of CBM was designed and its simulation analysis was carried out. The results showed that this process could thoroughly remove im purities such as nitrogen, oxygen, and obtain relatively high concentrations of LNG product. The impact of the reflux ratio, plate number and feeding temperature on the oxygen and methane content of the bottom product was analyzed. Additional ly, energy consumption of the equipment involved in the low temperature fractionation process was analyzed.