Abstract: Apparatus for liquefying natural gas, comprising a series of heat exchangers for cooling the natural gas in countercurrent heat exchange relationship with a refrigerant, compression means for compressing the refrigerant, expansion means for isentropically expanding at least two separate streams of the compressed refrigerant, said expanded streams of refrigerant communicating with a cool end of a respective one of the heat exchangers, and a precooling refrigeration system for precooling the natural gas to a temperature below 0° C. before it is fed to the series of heat exchangers, and for precooling the compressed refrigerant discharged from a warm end of the series of heat exchangers to a temperature below 0° C. before it is fed back into the series of heat exchangers or to the expansion means.

Abstract: A support structure that is either floatable or otherwise adapted to be disposed in an offshore location at least partially above sea level. A natural gas liquefaction system is located on or in the support structure and has a series of heat exchangers for cooling the natural gas in a countercurrent heat exchange relationship with a refrigerant. One or more compressors compress the refrigerant which is divided into two separate streams. Each stream is fed to a liquid expansion turbine where it is isentropically expanded. The expanded streams of refrigerant are then fed to the cool end of one of the heat exchangers.

Abstract: A natural gas liquefaction process comprises passing natural gas through a series of heat exchangers in countercurrent relationship with a gaseous refrigerant circulated through a work expansion cycle. The work expansion cycle comprises compressing the refrigerant, dividing and cooling the refrigerant to produce at least first and second cooled refrigerant streams, substantially isentropically expanding the first refrigerant stream to a coolest refrigerant temperature, substantially isentropically expanding the second refrigerant stream to an intermediate refrigerant temperature warmer than said coolest refrigerant temperature, and delivering the refrigerant in the first and second refrigerant streams to a respective heat exchanger for cooling the natural gas through corresponding temperature ranges.