单级混合冷剂天然气液化工艺优化及分析

Optimization and analysis of single-stage mixed-refrigerant natural gas liquefaction process

以四川省某天然气液化工厂实际运行参数为依据,采用HYSYS软件模拟了单级混合冷剂天然气液化工艺流程。以比功耗为优化目标,分别使用黑箱(BOX)算法、序列二次规划(SQP)算法、遗传算法(GA)对冷剂组分、冷剂压缩压力、蒸发气(BOG)压缩压力等操作参数进行了优化,并从比功耗和换热器传热温差两方面对比了各算法的优化效果。对比发现,相较于现有运行工况的比功耗0.3837(kW·h)/kg,BOX算法降低了3.99%,SQP算法降低了6.62%,GA降低了7.64%。总体上,GA对天然气液化工艺操作参数的优化效果最好。

Based on the actual operating parameters of a natural gas liquefaction plant in Sichuan Province,the HYSYS software was used to simulate the single-stage mixed refrigerant natural gas liquefaction process.Taking specific power consumption as the optimization goal,BOX method,SQP method and genetic algorithm(GA)were used to optimize the operating parameters such as refrigerant composition,refrigerant compression pressure and boil off gas(BOG)compression pressure.The optimization effects of each method were compared from two aspects of specific power consumption and heat transfer temperature difference of heat exchanger.It is found that compared with the specific power consumption of 0.3837(kW·h)/kg under the existing operating conditions,the BOX method reduced by 3.99%,the SQP method reduced by 6.62%,and the GA reduced by 7.64%.In general,the GA has the best optimization effects on the operating parameters of the natural gas liquefaction process.