基于RSV工艺装置提高乙烷收率的工艺技术

Approaches for improving ethane recovery rate based on RSV process facility

关键词:  天然气  RSV工艺  深冷工艺  提高  乙烷收率 

Key words:  natural gas  recycle split vapor process  cryogenic processs  improve  ethane recovery rate

摘要:

目的 为研究大型天然气深冷工艺装置因膨胀机未投运、关键工艺参数未及时优化调整造成脱甲烷塔操作难度大等导致装置乙烷收率降低等问题,现采用适时投运膨胀机、优化液烃回收装置关键工艺参数等措施开展提高乙烷收率的工艺技术研究。方法 基于Aspen HYSYS软件建立装置工艺计算模型,对比分析低温分离器温度、回流贫气和过冷原料气流量及温度等关键设计运行参数对提高乙烷收率的影响,考查上述关键工艺参数对装置乙烷收率的效果。结果 经现场验证得出结论,低温分离器温度优化为-68.8～-68.0 ℃,回流贫气流量和温度分别调整为(7.38～7.60)×10⁴ m³/h、-101.45～-100.05 ℃,过冷原料气流量和温度分别调整为(7.45～7.63)×10⁴ m³/h、-101.48～-100.45 ℃,装置实现液烃产品年增产17.56×10⁴ t。结论 该项目的应用可实现装置乙烷平均收率由30%提高至90%以上,每年可以获得较高的经济效益,具有较大的推广价值。 

Abstract:

Objective Aiming at the issues of non-running expander, non-optimized main process parameters and difficult operation in large-scale natural gas cryogenic process facility, the approaches of expander commissioning, optimizing main process parameters in natural gas liquid (NGL )recovery unit to improve ethane recovery rate are researched. Methods Based on process models by Aspen HYSYS simulation software, the effects of expander commissioning and optimizing main process parameters such as low-temperature separator (LTS) temperature, reflux lean gas flow rate, sub-cooled gas flow rate on improving ethane recovery rate and the practical ethane production are compared and investigated respectively. Results The LTS temperature has been optimized to the range of -68.8 ℃ to -68.0 ℃. The reflux lean gas temperature and flow rate have been adjusted to the range of -101.45 ℃ to -100.05 ℃ and (7.38-7.60)×10⁴ m³/h, respectively. The sub-cooled gas temperature and flow rate have been adjusted to the range of -101.48 ℃ to-100.45 ℃ and (7.45-7.63)×10⁴ m³/h, respectively. After the above applications of these efficient measures in the natural gas cryogenic facility and field test, annual NGL production has already increased 175 600 tons. Conclusion sAfter the implementation of these measures, the ethane average recovery rate has been increased from 30% to more than 90%. It can not only obtain huge economic benefits, but also has a good prospect of promotion and application.