Simulation and optimization of natural gas liquefaction process based on two-stage throttling refrigeration cycle
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 conducting research on the two-stage throttling refrigeration cycle natural gas liquefaction process and analyzing and optimizing its parameters can provide reference for the design innovation of natural gas liquefaction process,and will contribute to the high-quality development of the natural gas liquefaction industry.
万方数据
维普
