Natural gas liquefying system and liquefying method

摘要

[Problem] To suppress excessive increases in the temperature of a raw material gas that is introduced to a liquefying device after being compressed by a compressor and thereby to easily adjust the temperature level of the raw material gas such that said temperature level nears the temperature level of the site where the gas is introduced to the liquefying device. [Solution] A natural gas liquefying system (1) that is characterized by being provided with: a first expander (3) that expands a raw material gas that is a natural gas obtained by pressurization; first coolers (10, 11, 12) that cool the raw material gas; a distilling device (15) that distills the raw material gas that is cooled by the first coolers and thereby reduces or eliminates the heavy components of the raw material gas; a first compressor (4) into which is introduced an overhead distillate from which the heavy components of the raw material gas have been reduced or eliminated in the distilling device; and a liquefying device (21) that liquefies, by means of a heat exchange with a coolant, the gaseous phase component that is separated from a compressed gas that is compressed in the first compressor.