Characteristic of Cryogenic Cascade LNG Liquefaction Process

Abstract

In this paper, several types of natural gas liquefaction process with 2 staged compression cascade processes are designed and simulated to develop the liquefaction process which is the core technology in the Industry of natural gas liquefaction plant. These include the cascade cycle with inter-cooler which is consisted of Propane, Ethylene and Methane cycle. After this, two liquid-gas heat exchangers are applied to between methane and ethylene cycles, and between ethylene and propane cycles. Moreover, the expander is applied to above cascade process. Also, these cycles are compared with basic cascade process. The compressor work and refrigeration capacity of two staged cascade process with inter-cooler are 16.34% and 3.06% lower than that of basic respectively and COP of that is 15.88% higher than that of basic process. Liquid-gas heat exchanger process showed about 18.77% and 6.36% lower compressor work and refrigeration capacity, and 15.27% higher COP than that of basic process. At last, compressor work and refrigeration capacity of expander process is 19.04% and 6.77% lower and COP of that is 15.88% higher than basic cycle respectively. Also, the yield efficiency of LNG has been improved comparing with expander process by 18.99% lower specific power.