METHOD FOR ISOLATING A STREAM OF C2+ HYDROCARBONS CONTAINED IN THE REFINERY RESIDUAL GAS, AND PLANT FOR IMPLEMENTATION THEREOF

摘要

FIELD: gas industry.;SUBSTANCE: invention relates to a method for isolating a stream (12) of C2+ hydrocarbons contained in the refinery residual gas (16), including the following stages: forming a residual stream (28) from said refinery residual gas (16); supplying said residual stream (28) to the evaporation tank (30) to form a gaseous overhead stream (32) of the evaporation tank and a liquid bottom stream (34) of the evaporation tank; supplying said bottom stream (34) of the evaporation tank to the distillation column (38); cooling said overhead stream (32) of the evaporation tank in a heat exchanger (36), resulting in a cooled overhead stream (58) of the evaporation tank; separating said cooled overhead stream (58) of the evaporation tank into a liquid lower stream (64) supplied into the distillation column (38) and a gaseous upper stream (80); supplying the lower stream (64) to the distillation column (38) above the inlet of the bottom stream (34) of the evaporation tank; extracting the stream (12) of C2+ hydrocarbons in the bottom part of the distillation column (38); removing the gaseous overhead stream (72) in the head part of the distillation column (38); forming at least one effluent stream (14) from the overhead stream (72) of the distillation column and/or from the upper stream (80); heating said or each effluent stream (14) in the heat exchanger (36) by means of heat exchange with the overhead stream (32) of the evaporation tank. Separation of the cooled overhead stream (58) of the evaporation tank includes supplying the cooled overhead stream (58) of the evaporation tank into an absorber (40) and introducing a methane-rich stream (42) into the absorber (40) to bring the cooled overhead stream (58) of the evaporation tank into contact with the methane-rich stream (42), wherein the molar content of methane in the methane-rich stream (42) is greater than 90 mol.% The invention also relates to a plant (10) for isolating a stream (12) of C2+ hydrocarbons from the refinery residual gas (16).;EFFECT: effective and stable isolation of valuable products from the refinery residual gas, while simultaneously limiting the capital and operating costs of the method.;14 cl, 1 tbl, 1 dwg