FIELD: technological processes.
SUBSTANCE: invention relates to low-temperature separation plants and can be used in gas industry for extraction of hydrocarbons C2+ from natural gas. Proposed is a unit including, 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, three reducing devices, a separator, a dephlegmator and a demethanizer. Alternative 2 instead of equipment of external cooling circuit includes compressor, refrigerator and fourth reducing 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 and directed to dephlegmator, cooled by low pressure gas, which is then heated in the 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 is discharged from refluxer, reduced, weathering to produce weathering gas supplied to low pressure gas line, and is fed via second recovery heat exchanger into 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, a second recuperative heat exchanger and reduced.
EFFECT: high output of hydrocarbons C2+.
4 cl, 2 dwg
