天然气单塔深冷脱氮工艺研究

Study on Single Column Cryogenic Denitrification of Natural Gas

随着资源的深入开发,采用注氮工艺作为增产措施(EOR)而采出的天然气中含氮量最高可达40%,严重影响天然气综合利用价值。针对塔河油田注氮开发采出天然气含氮量高且含氮量波动特别大的气源条件,本文在消化吸收典型的双塔深冷脱氮工艺技术上进行优化改进,提出了一种适用于含氮量波动大的天然气单塔深冷脱氮工艺,该工艺具有流程简化、操作简单等显著特点。采用ASPEN HYSYS软件对单塔深冷脱氮工艺进行模拟计算,分析了精馏塔压力、原料天然气中含氮量变化以及压缩机后排气压力等参数对流程比功耗、损失及流程适应性的影响,结果表明:单塔深冷脱氮工艺具有甲烷提取率高、能耗低、对原料气组份变化适应性好等优点。

With the further exploitation of resource,the maximum nitrogen content in natural gas produced by adopting the nitrogen injection process as an output increase measure(EOR)can reach 40%,which seriously affects the comprehensive utilization value of natural gas.Considering the high nitrogen content and extremely large nitrogen content fluctuations of the natural gas source produced by nitrogen injection process in Tahe Oilfield,a single-column cryogenic denitrification process was adopted after absorbing and optimizing the typical domestic and worldwide double tower cryogenic denitrification technology.The single-column cryogenic denitrification process has the characteristics of simplified process and simple operation.The ASPEN HYSYS software was used to simulate the single-column cryogenic denitrification process,and the parameters such as the rectification tower pressure,the change in nitrogen content of in the raw natural gas,and the exhaust pressure after the compressor were compared to the process specific power consumption,exergy loss,and process.The results show that the single-column cryogenic denitrification process has the advantages of high methane extraction rate,low energy consumption,and good adaptability to change in the composition of the feed gas.