天然气凝液回收直接换热工艺分析及改进

Analysis and improvement of direct heat exchange process for natural gas condensate recovery

天然气凝液回收对防止天然气管道运输中轻烃凝液析出以及实现天然气资源的分层次利用具有十分重要的意义。但是,当原料气压力与外输气压力均较高时,回收能耗与成本将会大大增加。利用Aspen HYSYS,对直接换热工艺(DHX)凝液回收进行了分析及改进。在保证回收率的前提下,采用复叠式制冷循环代替膨胀机制冷,并增加精馏塔一台,进一步控制DHX工艺塔顶进料中丙烷含量。改进的DHX工艺综合能耗减少约30%火用损失减少1230.79 kW。改进的工艺在运行2.3年后,累计效益将高于改进增加的投资。

The recovery of natural gas condensate is of great significance in preventing the precipitation of light hydrocarbon condensate in natural gas pipeline transportation and realize the graded utilization of natural gas resources.However,when the pressures of the raw material gas and external gas are both high,the energy consumption and recovery costs will be greatly increased.Aspen HYSYS was used to analyze and improve the condensate recovery of the direct heat exchange process(DHX).Under the premise of ensuring the recovery rate,the cascade refrigeration cycle was used to replace the expander refrigeration,and a rectification tower was added to further control the propane content in the feed at the top of the DHX tower.The energy consumption of the improved DHX process is reduced by about 30%,and the exergy loss is reduced by 1230.79 kW.After 2.3 years of operation,the cumulative return will cover the increase in investment for the improvement.