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 an plant which includes, in version 1, a drying unit, an external cooling circuit in the evaporator, a compressor, a condenser and a reducing device, recuperative heat exchangers, reducing devices, separator, fractionating absorber, demethanizer and deethanizer. Version 2 instead of external cooling circuit equipment includes a compressor, a refrigerator and a reducing device. In operation of version 1, high-pressure gas is dried and cooled in a first recovery heat exchanger, an evaporator and a second recovery heat exchanger, cooled gas is reduced and directed to a fractionating absorber cooled by low pressure gas, which is then heated in the first recuperative heat exchanger. During circulation, the coolant after heating in the evaporator is compressed by a compressor driven by at least one of the expanders, cooled in a condenser and reduced. Absorption gas is reduced and mixed with methane-containing gas to obtain low-pressure gas. Absorbate is removed from the fractionating absorber, reduced, weathered to produce weathering gas supplied to the low-pressure gas line, and the pump is supplied through the second recuperative heat exchanger to the demethanizer, from which methane-containing gas and hydrocarbons C2+ are removed, which are separated in a deethanizer into a ethane fraction and a propane-butane fraction, part of which is fed into a fractionating absorber as an absorbent. Operation of version 2 differs by the fact that part of high pressure gas is compressed by compressor actuated by means of at least one of expanders, cooled in refrigerator, second recovery heat exchanger and reduced.
EFFECT: invention increases output of hydrocarbons C2+.
2 cl, 2 dwg
