| 摘要 |
Disclosed is a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process (a) said gas stream is cooled under pressure to provide a cooled stream; (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered; wherein following cooling, said cooled stream is divided into first and second streams; and (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled; (2) said expanded cooled first stream is heated and is thereafter supplied to said distillation column at an upper mid-column feed position; (3) said second stream is expanded to said lower pressure and is supplied to said distillation column at a mid-column feed position below said upper mid-column feed position; an overhead vapor stream is withdrawn from an upper region of said distillation column and heated, thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; (5) a distillation vapor stream is withdrawn from a region of said distillation column below said upper mid-column feed position and above said mid-column feed position and is directed into heat exchange relation with said expanded cooled first stream and said overhead vapor stream, whereby said distillation vapor stream is cooled sufficiently to condense at least a part of it and thereby form a residual vapor stream and a condensed stream, thereby supplying at least a portion of the heating of steps (2) and (4); (6) at least a portion of said condensed stream is supplied to said distillation column at a top feed position; and (7) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered. |
