Comparative study and multi-objective optimization of various configurations in natural gas liquefaction process

Abstract

PRICO process is a promising method for liquefaction of the natural gas which is sometimes used with some optional equipment. Although the PRICO process is widely used in natural gas liquefaction, the configuration leading to the most desirable performance has not been determined. The liquefaction rate and the energy consumption are two important factors to evaluate the performance of the PRICO process. In this paper, the PRICO process with five different configurations were simulated and compared. By the means of the multi-objective optimization method, the liquefaction rate and the energy consumption were optimized, simultaneously, for the each of the procedures. The five different simulated configurations are simple PRICO process, simple process with third compressor, simple process with second heat exchanger, simple process with precooling heat exchanger and full-set process. The optimization results demonstrated that the three-compressor and the full-set processes achieved the maximum liquefaction rate (96.51) and the minimum energy consumption (1219.53 kW), respectively. The economic analysis has also presented and revealed that the three-compressor process had the highest net profit (730.9288 M$/25 years) among the configurations. In other words, three-compressor process outperformed other configurations with respect to the operation and economics (maximum liquefaction rate of 96.51 and net profit of 730.9288 M$/25 years).