大涝坝天然气处理装置工艺改造研究

Study on the Technological Reform for Gas Processing Unit in Dalaoba

关键词:  天然气  轻烃  膨胀机  模拟

Key words:  natural gas  light hydrocarbon  expander  simulation

摘要:

大涝坝天然气处理装置采用膨胀制冷工艺,其设计天然气日处理量为25×104m3。自2005年投产以来,随着大涝坝凝析气田不断开发天然气的日处理逐渐增加至30×104m3左右,超过了设计处理能力,装置处于超负荷运行,造成C3及C3+收率降低;另外还存在大约每天10×104m3未经过严格脱烃的天然气直接进入了外输管网,造成外输气烃露点无法保证以及C3+资源未能充分回收。针对大涝坝天然气处理装置超负荷运行问题,在原有流程的基础上将分子筛脱水系统改造为四塔流程;制冷系统改造为副冷箱加双膨胀机流程,并进行了计算机模拟。结果 表明:改造后装置的处理能力增加了15×104m3/d,外输干气的烃露点下降了25℃,C3的收率增加了17.4%,C3+收率增加11.8%;液化气产量增加了18.6t/d,稳定轻烃产量增加了2.6t/d。

Abstract:

Gas processing unit in Dalaoba uses expansion refrigeration process and its processing ability is 250,000 m3/d. Since the commissioning of unit in 2005,processing ability of gas increased to about 300,000 m3/d,with gas field develop in Dalaoba more than the design capacity.Overload operation of the devices result in lower yield of C3 and C+3. There are also about 100,000 m3/d gas directly into a pipeline without de-hydrocarbon strictly,causing hydrocarbon dew point of transmission gas can not be guaranteed,and the C+3 resources are not fully recovered. According to overload operation problem of gas treatment unit in Dalaoba,the system of molecular sieve dehydration is transformed as 4 towers process; the refrigeration system is reformed as the vice-cold box with double expander process based on the original process,and the process is simulated by computer. The results showed that: after transformation,the processing ability is increased 150,000 m3/d; the hydrocarbon dew point of transmission gas decreased by 25℃;the yield of C3 increased by 17.4%,the yield of C+3 increased by 11.8%; liquefied gas production increased by 18.6t/d; the stabilized light hydrocarbon production increased by 2.6t/d.