天然气轻烃回收DHX工艺优化研究

Design and optimization of DHX process for light hydrocarbon recovery from natural gas

设计了一种用于天然气轻烃回收的DHX工艺,并考察了原料气预冷温度、膨胀机出口压力与原料气中C1/C2组成对DHX塔温度、丙烷压缩机功率、产品气增压机功率、膨胀机功率和C3+收率的影响。结果表明:丙烷压缩机功率和C3+产品收率均随着原料气预冷温度的降低先增大后减小;随着膨胀机出口压力的降低,DHX塔出口物料温度逐渐降低,产品气增压机功率、膨胀机功率和C3+产品收率均显著增加;原料气中n(C1)/n(C2)逐渐增大,使得DHX塔进出口物料温度明显降低,导致C3+产品收率逐渐增加。优化后DHX工艺为原料气预冷温度为-40℃,膨胀机出口压力为3.2MPa,C3+收率可达到97.18%。

A DHX process for light hydrocarbon recovery from natural gas was designed, and the influences of feed gas pre-cooling temperature, outlet pressure of expander, and C1/C2 mole ratio of feed gas on DHX tower temperature, propane compressor power, compressor power of product gas, expander power and C3^＋ recovery rate were investigated. The results showed that propane compressor power and C3^＋recovery rate increased at first and then decreased with the decrease of feed gas pre-cooling temperature;the outlet temperature of DHX tower decreased while the compressor power of product gas, expander power and C3^＋ recovery rate increased with the decrease of the outlet pressure of expander;and increasing C1/C2 mole ratio of feed gas led to the obvious decrease of the inlet and outlet temperature of DHX tower, and ultimately increased C3^＋recovery rate. The optimum operation parameters for the DHX process were feed gas pre-cooling temperature of-40℃and expander outlet pressure of 3.2MPa, and C3^＋recovery rate could reach 97.18%under these conditions.