Liquefaction processes
Natural gas liquefaction

To liquefy natural gas, the thermodynamic path followed is shown in figure 6 : the gas is cooled under pressure, then it reaches a zone where the gas and liquid phases coexist, then it becomes totally liquid under pressure, it is then sub-cooled, and finally expanded to be stored at approximately atmospheric pressure.

The various industrial processes used for this type of liquefaction are all based on compression-expansion cycles. The principle of these cycles is shown in figure 7 .

The refrigerant, compressed to a pressure sufficient to condense at the temperature of the available cold source, is expanded to vaporize....