Analysis of the influence of mixed refrigerant pressure on performance of natural gas liquefaction process from a new view of interactions among process parameters

Refrigerant pressure is an important parameter affecting refrigeration and cryogenic system performance. However, when we study the impact of the mixed refrigerant pressure on system performance, it is often difficult to obtain exact results, mainly due to the complicated and nonlinear interactions among process parameters. So far, there are only a few experimental or numerical studies in which they all kept other process parameters unchanged while changing the pressure parameters, resulting in one-sided and limited conclusions. This paper is the first to study the influence of the mixed refrigerant pressure on the performance of the propane pre-cooled mixed refrigerant process of natural gas liquefaction from the view of interactions among process parameters in four aspects: the system refrigerant composition, flow rate, heat exchangers, and energy consumption, where the process parameters used in the analysis are obtained using the proposed pinch analysis approach with interactive optimization procedure of process parameters guided by the combination of the specific heat capacity properties of feed natural gas and composite curves in the pinch analysis. In contrast to previous studies, the above analysis strategy and the conclusions drawn in this paper are more realistic, exact, and of higher theoretical and practical value.