| 摘要 |
Low-temp. sepn. of a feed gas into stream contg. 3C+ and/or 4C+ hydrocarbons and a light gas stream (A) contg. H2, N2, CO, CO2, CH4 and/or 2C hydrocarbons comprises: (a) cooling to effect partial condensation by indirect heat exchange against process streams; (b) phase sepg. into heavy liq. stream 1, contg. heavy hydrocarbons, and vapour stream 1, contg. light components; (c) rectifying vapour stream 1, giving light gas stream 1 and a segregated heavy liq. stream 2, by low temp. dephlegmation, in which vapour stream 1 is cooled by indirect heat exchange with light gas stream 1, which is expanded to a lower temp. and pressure; (d) expanding heavy liq. streams 1 and 2 to a lower pressure and temp. and then using one or both in step (a), by indirect heat exchange with partial vaporisation, to cool the feed gas; (e) separately introducing heavy liq. streams 1 and 2 into a distn. column operated with an overhead condenser and bottom reboiler; (f) sepg. into 3C+ and/or 4C+ hydrocarbons as bottom prod. and a light gas stream 2; and (g) recovering light gas streams 1 and 2 to produce prod. light gas stream(s) (A).
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