Liquefied natural gas (LNG) is an important energy source and occupies an important proportion in natural gas consumption, therefore, the selection of appropriate liquefaction processes and related optimization should be seen as subjects of great importance. Accordingly, in the present review, we provide a comparative and critical analysis of the current status of natural gas liquefaction technology through examination of the advantages and disadvantages associated with three natural gas liquefaction processes (namely, the cascade liquefaction cycle, the expander-based cycle and the mixed refrigerant cycle). It is shown that the energy consumption related to the cascade refrigeration cycle is the lowest. Compared with it, the mixed refrigerant cycle has the advantages of being a simpler process, with less units, low investment cost and low requirements in terms of refrigerant purity. The expander-based cycle can be started and stopped quickly and simply, but the power consumption is relatively high.

Natural gas; liquefaction; process; comparison; energy consumption