FIELD: oil and gas industry.
SUBSTANCE: invention relates to low-temperature separation plants and can be used in gas industry for extraction of hydrocarbons C2+ from natural gas. Disclosed is a plant which includes, in version 1, a drying unit, an external cooling circuit in the evaporator, a compressor, a condenser and a reducing device, two recuperative heat exchangers, two reducing devices, a separator, a dephlegmator and a demethanizer. Version 2 instead of external cooling circuit equipment includes compressor, refrigerator and third reduction device. In operation of version 1, high-pressure gas is dried and separated into two streams, first is cooled in first recuperative heat exchanger, and second one – in evaporator and in second recuperative heat exchanger, then flows are combined, reduced, separated in separator condensate and sent to dephlegmator, cooled by low pressure gas, which is then heated in first recuperative heat exchanger and discharged. During circulation, the coolant of the external circuit after heating in the evaporator is compressed by a compressor driven by at least one of the expanders, cooled in a condenser and reduced. Reflux gas is reduced and mixed with methane-containing gas to obtain low-pressure gas. Reflux gas is discharged from the dephlegmator, mixed with condensate and pump through a second recovery heat exchanger, into a demethanizer, from which hydrocarbons C2+ and methane-containing gas. Operation of version 2 is characterized by that the second high-pressure gas stream is compressed by a compressor driven by at least one of the expanders, cooled in a cooler, in a second recuperative heat exchanger and reduced.
EFFECT: invention increases output of hydrocarbons C2+.
6 cl, 2 dwg
