FIELD: technological processes.
SUBSTANCE: invention relates to low-temperature dephlegmation units with rectification and can be used in gas industry for extraction of hydrocarbons C2+ from main natural gas. Disclosed group of inventions includes versions of main gas deethanization units with production of LNG. Deethanization unit of main gas to produce LNG, equipped with high and low pressure gas lines, includes drying unit, recuperative heat exchanger, expanders connected to compressor by means of kinematic or electrical connection, a refluxer with a reflux line connected by a reflux gas feed line equipped with an expander and a low-pressure gas supply line with a separator which is equipped with methane-containing gas feed lines from the fractionation unit and a wide fraction of light hydrocarbons to the fractionation unit, wherein as a separator a demethanizer is installed, connected to the refluxer by a reflux feed line with a reducing device, equipped with an output line LNG located below the dephlegmation gas supply line abutment, wherein the wide hydrocarbon light fraction feed line is connected to the cooling unit located on the bypass heat exchanger line and equipped with the compressor, and the supply line of the wide fraction of light hydrocarbons after the cooling unit is connected to the demethanizer.
EFFECT: high output of hydrocarbons C2+ due to reduction of high-pressure gas temperature by arrangement of additional cooling unit and expansion of products range due to installation of demethanizer with LNG output line.
2 cl, 2 dwg
