FIELD: gas liquefaction. SUBSTANCE: invention refers to technique of liquefaction of flow of compressed gas rich in methane with the aid of heat exchanger cooled by stage cooling system to win liquid product abounding in methane and having temperature above -112 C. In accordance with technique flow of compressed gas is brought into heat-exchange contact with first cooling cycle that involves at least one cooling stage that cools flow of gas with the use of first part of first cooling agent to obtain flow of cooled gas. Flow of cooled gas is brought into heat- exchange contact with second cooling cycle involving at least one cooling stage which reduces temperature of flow of cooled gas to produce liquefied flow of gas rich in methane, having temperature of about -112 C and pressure sufficient for liquefied flow to be in point of start of its boiling or below. EFFECT: updated technique of liquefaction of natural gas by way of reduced number of employed units and consumed power. 11 cl, 3 dwg, 2 tbl
