基于J-T阀和机械制冷工艺调节天然气露点的热力学及经济分析  

Thermodynamic and economic analysis of tuning the natural gas dew point based on a J-T valve and a mechanical refrigeration process

作　　者：杨铜林 谭川江[1] 李国娜[1] 张波[1] 王坤[1] 李浩玉 黄靖珊 YANG TongLin;TAN ChuanJiang;LI GuoNa;ZHANG Bo;WANG Kun;LI HaoYu;HUANG JingShan(PetroChina Tarim Oilfield Company,Kuerle 841000;PetroChina Changqing Oilfield Company,Xi’an 710000;CPECC Xinjiang Branch,Karamay 834000,China)

机构地区：[1]中国石油塔里木油田分公司,库尔勒841000 [2]中国石油长庆油田分公司,西安710000 [3]中油(新疆)石油工程有限公司设计分公司,克拉玛依834000

出　　处：《北京化工大学学报（自然科学版）》2024年第5期10-19,共10页Journal of Beijing University of Chemical Technology(Natural Science Edition)

摘　　要：在天然气输送过程中,常采用J-T阀制冷、机械制冷这两种低温分离法析出液烃和水来控制露点保证管输安全。针对两种工艺结构差异较大的情况,从能量、经济上对J-T阀制冷和机械制冷这两种天然气露点调节方法进行了模拟分析。研究结果表明,两种工艺的烃露点降接近,而机械制冷工艺的水露点降更高。在(火用)分析对比上,JT阀制冷工艺(火用)损(5 159kW)明显高于机械制冷工艺(1 961kW),机械制冷工艺的系统换热效率更高,使得其整体(火用)效率高于J-T阀制冷;高级(火用)分析结果显示,机械制冷工艺可避免(火用)损占比(69.8%)高于J-T阀制冷工艺(66.7%),改进潜力更大且代价更低。在资本投资对比方面,机械制冷工艺采用外部制冷系统提供冷量,设备的购置成本更高,但其保留了原料气的压力能,在相同外输条件下运行成本更低。综合投资成本及产品收益,在整个运行周期,机械制冷工艺的收益高出812.64×10^(4)美元。对两种工艺的敏感性分析显示,丙烷的冷却性能不会随其流量的增加而持续增加;随着地层压力的降低,利用压差来改善天然气性质的工艺效果低于采用外部丙烷制冷工艺。In natural gas transportation,low-temperature separation methods(J-T valve refrigeration,mechanical refrigeration)are often used to separate liquid hydrocarbons and water to control the dew point and ensure pipeline transportation safety.Given the significant differences between the two processes,we have simulated and analyzed the J-T valve refrigeration and mechanical refrigeration from both energy and economic aspects.The results show that the hydrocarbon dew point drop of the two processes is close,while the water dew point drop of the mechanical refrigeration process is higher.On the basis of exergy analysis,the J-T valve refrigeration process has a higher exergy destruction(5159 kW)than the mechanical refrigeration process(1961 kW).The mechanical refrigera-tion process has a higher system heat transfer efficiency,which makes its overall efficiency higher than J-T valve refrigeration.Detailed analysis shows that the avoidable energy destruction(69.8%)of the mechanical refrigera-tion process is higher than the J-T valve refrigeration process(66.7%),with greater improvement potential and lower cost.In terms of capital investment,the mechanical refrigeration process uses an external refrigeration system to provide cooling capacity,resulting in higher equipment purchase cost,but it retains the pressure energy of the feed gas.Under the same export conditions,the operating cost and the comprehensive investment cost of the mechanical refrigeration process is lower than the J-T valve refrigeration process.Over the whole operation cycle,the mechanical refrigeration process resulted in a cost advantage of 812.64×10^(4) dollars.A sensitivity analysis of the two processes shows that the cooling performance of the refrigerant does not continue to increase with increasing flow rate.As the formation pressure decreases,the effect of using differential pressure of natural gas is less than that of external refrigerant refrigeration.

关 键 词：节流阀 机械制冷 (火用)分析 经济分析 敏感性分析 

分 类 号：TE89[石油与天然气工程—油气储运工程]