FIELD: oil and gas industry.
SUBSTANCE: invention relates to low-temperature separation plants and can be used in gas industry for production of hydrocarbons C2+ from natural gas. Proposed is a plant including, in version 1, a drying unit, an external cooling circuit comprising an evaporator, a compressor, a condenser and a reducing device, two recuperative heat exchangers, two expansion devices, a pump, a dephlegmator and a demethanizer. Version 2 instead of external cooling circuit includes compressor, refrigerator and third expander. 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 in the first expander and sent to a dephlegmator, cooled with low pressure gas, which is then heated in the first recuperative heat exchanger and discharged. During circulation, the cooling agent of the external circuit after heating in the evaporator is compressed with a compressor driven by expanders, cooled in a condenser and reduced. Dephlegmated gas is reduced in the second expander and mixed with the methane-containing gas to form a low-pressure gas. From dephlegmator reflux is supplied through second recovery heat exchanger to demethanizer, from which hydrocarbons C2+ and methane-containing gas are removed. Operation of version 2 is characterized by that the second high-pressure gas stream is compressed by a compressor driven by expanders, cooled in a cooler, a second recuperative heat exchanger and reduced by means of a third expander.
EFFECT: invention increases output of C2+ hydrocarbons.
2 cl, 2 dwg
