FIELD: technological processes.
SUBSTANCE: invention relates to low-temperature dephlegmation with rectification units and can be used in gas industry for deethanization of main natural gas. Disclosed group of inventions includes versions of plants LTDR for producing hydrocarbons C2+ from main gas, including drying unit, recuperative heat exchanger, cooling assembly with a second recuperative heat exchanger and a compressor connected to the expanders by kinematic or electrical coupling, an intermediate separator, reduction devices including at least one expander, as well as a dephlegmator, a demethanizer and a fractionation unit. During operation of the first version of main gas is drained, part is cooled in recuperative heat exchanger and reduced, another part is cooled in cooling unit, combined, separated in intermediate separator into condensate and gas, directed to dephlegmator, from which condensate and dephlegmation gas are removed. Reduced condensates are supplied to demethanizer, and the following is output from demethanizer: from the top – deethanized gas, which is mixed with reduced dephlegmation gas, heated in the dephlegmator heat exchange section and the first recuperative heat exchanger and discharged, from the middle part – flow of circulating reflux, which is heated in the second recuperative heat exchanger and returned to the demethanizer, bottom – demetanized condensate, which is fed into a fractionation unit for separation into products and methane-containing gas, which is returned to the demethanizer. Second version is characterized by supply of reduced dephlegmation gas to the demethanizer.
EFFECT: high output of hydrocarbons C2+.
2 cl, 2 dwg
