基于双级节流制冷循环的天然气液化工艺模拟与优化  

Simulation and optimization of natural gas liquefaction process based on two-stage throttling refrigeration cycle

作　　者：潘杰[1,2] 李媛媛 曹清寒 韩冰 王佳乐 李冉 PAN Jie;LI Yuanyuan;CAO Qinghan;HAN Bing;WANG Jiale;LI Ran(College of Petroleum Engineering,Xi'an Shiyou University,Xi'an,Shaanxi 710065,China;Engineering Research Center of Safety and Energy Saving in Oil&Gas Storage and Transportation,Universities of Shaanxi Province,Xi'an,Shaanxi 710065,China;Shanghai Marine Diesel Engine Research Institute,China State Shipbuilding Corporation Limited,Shanghai 201108,China;Natural Gas Research Institute,Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,Xi'an,Shaanxi 710075,China)

机构地区：[1]西安石油大学石油工程学院 [2]油气储运安全与节能陕西省高校工程研究中心 [3]中国船舶集团有限公司第七一一研究所 [4]陕西延长石油(集团)有限责任公司天然气研究院

出　　处：《天然气工业》2024年第6期111-121,共11页Natural Gas Industry

基　　金：国家自然科学基金项目“带温差发电装置的翼型肋印刷电路板式LNG气化器热—流—电耦合机理研究及多目标优化”(编号:52274064);“集成冷能温差发电装置的空温式气化器纵向翅片管热动态特性研究、能效分析及结构优化”(编号:51774237);西安石油大学研究生创新基金项目“基于双级节流式制冷循环以及双级喷射式制冷循环的两种天然气液化工艺设计”(编号:YCX2412012)。

摘　　要：液化天然气以其安全可靠、汽化潜热高、环境污染小等特点,在天然气贸易中占据重要位置,但天然气液化工艺系统功耗大以及液化成本较高等问题仍然存在。为此,基于2个双级节流制冷循环的天然气液化工艺系统,采用Aspen HYSYS软件,以比功耗、㶲效率、液化率和总成本作为评价指标,分析了关键参数对系统性能的影响;然后对2个系统进行了单目标和多目标优化,确定了系统的最优运行工况;最后对2个系统的最优性能进行对比,并采用LINMAP与TOPSIS方法对Pareto前沿进行决策,在最优工况下对系统设备进行了㶲分析。研究结果表明:①节流阀V1、V3、V4的节流压力增大,或乙烯质量流量增大,均会使系统比功耗先减后增;单目标优化结果显示系统B性能优于系统A;②采用LINMAP与TOPSIS方法对Pareto前沿的决策结果有所差别,基于LINMAP方法的决策结果表明,系统B的总成本优于系统A,系统A的比功耗和㶲效率更优,综合性能更好;③基于TOPSIS方法的决策结果表明,系统A的比功耗优于系统B,系统B的㶲效率和总成本更优,综合性能更好;④㶲分析结果显示,节流阀及换热器的㶲损较大。结论认为,开展双级节流制冷循环天然气液化工艺研究,对其进行参数分析和优化,能够为天然气液化工艺设计创新提供借鉴,将有助于天然气液化行业的高质量发展。Liquefied natural gas(LNG)plays an important role in natural gas trade due to its safety,reliability,high latent heat of vaporization and low environmental pollution.However,the natural gas liquefaction process system still has the problems of high power consumption and high liquefaction costs.In this paper,based on two natural gas liquefaction process systems with two-stage throttling refrigeration cycles,taking specific power consumption,exergy efficiency,liquefaction rate and total cost rate as evaluation indicators,the Aspen HYSYS software is used to analyze the influence of key parameters on the system performance.Then,single-objective and multi-objective optimizations are carried out on the two systems to determine the optimal operating conditions of them.Finally,the optimal performance of the two systems is compared,the LINMAP and TOPSIS methods are used to make decisions on the Pareto front,and exergy analysis was performed on the system equipment under the optimal operating conditions.The results show that an increase in the throttling pressure of V1,V3 and V4 or an increase in the mass flow rate of ethylene all allows the specific power consumption of the systems to first reduce and then increase,and the single-objective optimization results show that system B performs better than system A.The decision-making results of Pareto front using the LINMAP and TOPSIS methods are different:the decision-making results based on the LINMAP method show that the total cost rate of system B is better than that of system A,the specific energy consumption and exergy efficiency of system A are better,and its overall performance is better.The decision-making results based on the TOPSIS method show that the specific power consumption of system A is better than that of system B,the exergy efficiency and total cost rate of system B are better,and its overall performance is better.The exergy analysis results show that the exergy destruction of the throttle valve and the heat exchanger is greater.It is concluded that conducti

关 键 词：天然气液化 双级循环制冷 节流制冷 遗传算法 系统优化 多目标决策 㶲分析 

分 类 号：TE646[石油与天然气工程—油气加工工程]