关于西气东输天然气污液分析

ANALYSIS ON WASTE LIQUID IN WEST TO EAST GAS TRANSMISSION

西气东输首站油田—末站轮南站,是一座塔里木各气田产品气的混合气与西气东输长输管道进行天然气商务交接的计量站。其天然气的质量直接影响到下游的安全使用和计量。对西气东输油田末站排出污液的频率统计,发现进入冬季后,随着环境温度降低,析出液体渐多,排液的间隔缩短,排液频率增加。通过对主力气源克拉2与油田末站两处的析出液组分分析和排出液的物性数据,以及供气源沿线各测点水烃露点数据的分析认为,西气东输油田末站排出污液增加的原因主要是克拉2二厂的天然气在处理工艺流程中未脱重烃,冬季由于管道内的温度降低,析出液量较多。烃的露点高于水的露点,所以管线或设备中析出液主要是凝析油,含有少量的水醇混合物。但在油田末站交接点天然气的水露点可满足要求。建议对污液进行回收。

The last station (Lunnan station) of west to east gas transportation in Tarim Oilfield is a commercial trade station which transmits all gas from every oil-gas operational facility to west to east transporation pipeline.Quality of the gas from here will exert an important influence on down stream gauge and aplication.According to the drained waste liquid frequency statistics at the last station,however,it is found out that as tempreature lowers down in winter,the amount of condensated liquid becomes more dramastically,the peorid of draining liquid gets shorter and the frequency higher.By means of the physical property data of drained liquid and the component analysis of condensated liquid from main gas source Kela 2 and the last station,as well as the gydrocarbon dew point analysis along gas supplying spots,it is recognized the reason that the amount of drained waste liquid at the last station increases is mainly the heavy hydrocarbon in the gas supplied by Kela 2 factory being not eliminated in the process of treatment,in the winter time,because of decrease of the temperature in pipeline,the amount of condensated liquid gets more.The dew point of hydrocarbon is higher than that of water,so the condensated liquid is mainly condesated oil in pipeline or facilities,containig a little glycol and glycerol.The water dew point of the gas at the last station in oil field can meet the nees.It is suggested to recover the waste liquid.