Experimental studies on a natural gas liquefaction process operating with mixed refrigerants and a rectifying column

Abstract Small-scale natural gas liquefiers are developing rapidly in China due to the scattered and remote distribution of natural gas sources with small reserve. Compared to the complexity of cascade process and the relatively higher power consumption of expander process, the mixed refrigerant process is a preferable choice for small-scale liquefaction systems considering its relatively simple structure and moderate power consumption. In this paper, a single-cycle natural gas liquefaction process operating with mixed refrigerants and a rectifying column was proposed for small-scale applications, which could utilize a commercial oil-lubricated compressor to realize the liquefaction of natural gas. Experiments were conducted to study the influences of the operating pressures and mixed refrigerant compositions on the overall performances. Relatively optimum SPC values of 4.49 kW h/kg, 1.98 kW h/kg, 1.61 kW h/kg and 1.29 kW h/kg were obtained for the liquefactions of 0.1 MPa, 0.3 MPa, 0.5 MPa and 0.7 MPa pure methane, respectively.