Patent RU-2753698-C2 (RU)
Title: Hydrocarbon gas processing
Inventor: LINCH DZHO T
IPC: F25J3/02
Filed: 2017-08-04
Granted: 2021-08-19
Abstract: FIELD: gas industry. 
     SUBSTANCE: invention relates to a method and installation for separating a gas stream containing methane, C 2  components, C 3  components and heavier hydrocarbon components into a volatile fraction of the residual gas and a relatively less volatile fraction containing the main part of the above-mentioned components. The method includes the following stages: (a) processing the above-mentioned gas stream to obtain the first stream and the second stream; (b) expanding the condensed first stream to lower pressure and delivering it to an upper supply point in a distillation column; (c) expanding the cooled second stream to lower pressure and delivering it to an intermediate supply point in the distillation column and (d) fractionating the expanded additionally cooled first stream and second stream in the distillation column. Further, the components of the less volatile fraction are extracted into the cubic liquid flow, and the volatile fraction of the residual gas outcomes as an overhead vapor stream. In this case, (1) the overhead vapor stream is directed to an absorption device to come into contact with the condensed stream, in the result of which its less volatile components are condensed to form partially rectified vapor stream, (2) partially rectified vapor stream is collected in the upper zone of the absorption device and is sent to the device of heat and mass transfer, in the result of which additional rectified vapor stream and condensed stream are formed, after which the condensed stream is sent to the absorption device, (3) additional rectified vapor stream is sent to a heat exchange device and heated, after which it is output as outgoing vapor stream, (4) outgoing vapor stream is divided into the first part and the second part, (5) the first part is compressed to higher pressure to form compressed stream, (6) compressed stream is sent to the heat exchange device and cooled until condensation, in the result of which at least part of the heating stage (3) is realized and condensed stream is formed, (7) condensed stream is expanded to lower pressure, in the result of which it is additionally cooled to form rapidly expanded stream, (8) rapidly expanded stream is heated in the device of heat and mass transfer, in the result of which at least part of the cooling stage (2) is realized and heated rapidly expanded stream is formed, (9) heated rapidly expanded stream is combined with the second part to form a volatile fraction of the residual gas, (10) distilled liquid flow is collected and combined with expanded additionally cooled first stream to form combined raw material stream, after which it is directed to the upper supply point of raw materials on the distillation column, (11) combined raw material stream and expanded second stream are fractionated in the distillation column at lower pressure, in the result of which the components of the relatively less volatile fraction are extracted into the cubic liquid flow, and (12) quantities and temperatures of raw material streams incoming the distillation column are sufficient to maintain the overhead temperature, at which main parts of components are extracted into the cubic liquid flow.  
     EFFECT: improving the extraction of ethylene, ethane, propylene, propane and heavier hydrocarbon components.  
     34 cl, 14 dwg, 8 tbl, 4 ex