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 C₃⁺. 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 C₃⁺ 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 C₃⁺ increased by 11.8%; liquefied gas production increased by 18.6t/d; the stabilized light hydrocarbon production increased by 2.6t/d.