HYDROCARBON GAS PROCESSING Russian patent published in 2021 - IPC B01D53/00 F25J3/02 

FIELD: hydrocarbon gas processing.

SUBSTANCE: method and installation for a compact processing unit to improve the extraction of C₂ (or C₃) and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. The method involves treating the gas stream in one or more heat exchange stages and at least one separation stage to produce at least a first stream that is cooled under pressure until complete condensation, and at least a second stream that is cooled under pressure. The first stream is delivered to the top feed point in the distillation column. The second stream is delivered to the intermediate feed point in the distillation column. In the distillation column, the streams are fractionated at a lower pressure. The less volatile components are extracted into the stream of the cubic liquid. The volatile fraction exits as an overhead vapor stream, which is directed to an absorption device to come into contact with the condensed stream. The less volatile components condense to form a partially rectified vapor stream. The partially rectified vapor stream is collected in the upper zone of the absorption device and sent to the heat and mass transfer device. The less volatile components of the stream condense to form an additional rectified vapor stream and a condensed stream. The condensed stream is directed to the absorption device. The rectified vapor stream is directed to the heat exchanger and heated. The outgoing vapor stream is divided into the first part and the second part. The first part is compressed. The compressed steam is directed to the heat exchanger and cooled to condensation. The condensed stream is expanded. The rapidly expanded stream is heated in a heat and mass transfer device. The heated rapidly expanded stream is combined with the second part to form a volatile fraction of the residual gas. The condensed first stream is directed to the heat exchanger and further cooled under pressure. The additionally cooled first stream is expanded. The distilled liquid stream is collected from the lower zone of the absorption device and combined with the expanded additionally cooled first stream. The combined feed stream is directed to the top feed point on the distillation column. The combined feed stream and the expanded second stream are fractionated in the distillation column at a lower pressure.

EFFECT: improved extraction efficiency, reduced installation size, reduced air emissions.

34 cl, 6 tbl, 1 ex, 14 dwg