FIELD: production of ethylene from starting gas. SUBSTANCE: starting gas containing hydrogen, methane, ethylene and other C2--hydrocarbons and heavier hydrocarbons is cooled by means of cooling system employing binary mixture of cooling agents. Mixture of methane and ethylene or methane and ethane is compressed in compressor, thus obtaining binary mixture cooling agents. This binary mixture of cooling agents is gradually expanded, cooled and passed through row of heat exchangers where heat exchange between binary mixture being gradually cooled and starting gas takes place. Heat exchange is accompanied by cooling and separation of hydrogen and part of methane and obtaining flows of liquid in demethanizer at high concentration of ethylene and other C2-hydrocarbons and heavier hydrocarbons. These flows of liquid are fed to low-pressure demethanizer obtaining flow taken from upper part of demethanizer which mainly consists of methane which mainly consists of methane which is treated by gradually cooled binary mixture of cooling agents. flow of phlegm used for sprinkling the demethanizer and flow of end products taken from upper part of demethanizer are separated from said flow. Flow of phlegm thus obtained is returned to demethanizer. EFFECT: enhanced efficiency of cooling. 9 cl, 3 dwg, 1 tbl
