氮气双膨胀制冷提氦联产乙烷工艺设计与优化  

Process design and optimization of helium extraction and ethane co-production by nitrogen double expansion refrigeration

作　　者：马国光[1] 周明杰 雷洋 刘璐 邓昊天 MA Guoguang;ZHOU Mingjie;LEI Yang;LIU Lu;DENG Haotian(School of Petroleum and Natural Gas Engineering,Southwest Petroleum University,Chengdu 610500,Sichuan,China;Shenzhen Gas Corporation Ltd.,Shenzhen 518000,Guangdong,China)

机构地区：[1]西南石油大学石油与天然气工程学院,四川成都610500 [2]深圳燃气集团股份有限公司,广东深圳518000

出　　处：《低碳化学与化工》2024年第10期110-118,共9页Low-Carbon Chemistry and Chemical Engineering

摘　　要：国内某气田天然气中乙烷和氦气含量(物质的量分数)逐年升高,回收价值凸显。提出了一种氮气双膨胀制冷提氦联产乙烷工艺,采用HYSYS软件对该工艺进行了流程模拟,并对工艺流程的关键参数(低温分离器温度、脱甲烷塔塔顶回流比、二级提氦塔进料温度、二级提氦塔塔顶回流比、氮气膨胀端入口压力、氮气膨胀端出口压力和氮气制冷剂流量)对工艺指标的影响规律开展了研究。基于最优化理论,以C_(2)收率最大和二次粗氦浓度最大时装置总能耗最小为目标,采用Back Propagation(BP)神经网络算法对关键参数进行了寻优。结果表明,装置总能耗主要受低温分离器温度、氮气膨胀端出口压力和氮气制冷剂流量影响,C_(2)收率主要受低温分离器温度和脱甲烷塔塔顶回流比影响,氦收率主要受二级提氦塔进料温度影响。关键参数最佳组合为:低温分离器温度为-95.30℃,氮气制冷剂流量为1549.22 kmol/h,氮气膨胀端入口压力为3.25 MPa,氮气膨胀端出口压力为0.44 MPa,脱甲烷塔塔顶回流比为0.13,二级提氦塔进料温度为-150.57℃,二级提氦塔塔顶回流比为0.80。相比于优化前,优化后装置总能耗降低了1.46%,C_(2)收率提升了5.64%,二次粗氦浓度(物质的量分数)提升了1.81%。The content(mole fraction)of ethane and helium in the natural gas of a domestic gas field is increasing year by year,and the recovery value is highlighted.A process of helium extraction and ethane co-production by nitrogen double expansion refrigeration was proposed.The process was simulated by HYSYS software,and the influences of the key parameters of the process(temperature of the cryogenic separator,reflux ratio of the demethanizer top,feed temperature of the secondary helium extraction tower,reflux ratio of the secondary helium extraction tower top,inlet pressure of the nitrogen expansion end,outlet pressure of the nitrogen expansion end and flow rate of the nitrogen refrigerant)on the process indexes were investigated.Based on the optimisation theory,the Back Propagation(BP)neural network algorithm was used to optimise the key parameters with the objectives of minimising the total energy consumption of the unit when the C_(2) yield and the secondary crude helium concentration were maximised.The results show that the total energy consumption of the unit is mainly affected by temperature of the cryogenic separator,the outlet pressure of the nitrogen expansion end and the flow rate of the nitrogen refrigerant,and the C_(2) yield is mainly affected by temperature of the cryogenic separator and the reflux ratio of the demethanizer top,and the helium yield is mainly affected by the feed temperature of the secondary helium extraction tower.The optimal combination of key parameters is as follows:Temperature of the cryogenic separator is-95.30℃,flow rate of the nitrogen refrigerant is 1549.22 kmol/h,inlet pressure of the nitrogen expansion end is 3.25 MPa,outlet pressure of the nitrogen expansion end is 0.44 MPa,reflux ratio of the demethanizer top is 0.13,feed temperature of the secondary helium extraction tower is-150.57℃,and eflux ratio of the secondary helium extraction tower top is 0.80.Compared with the pre-optimization,the total energy consumption of the optimized unit is reduced by 1.46%,the C_(2) yield i

关 键 词：氮气双膨胀制冷 天然气提氦 乙烷回收 联产工艺 参数优化 BP神经网络算法 

分 类 号：TE646[石油与天然气工程—油气加工工程]