Hydrocarbon Gas Processing

In an apparatus 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 said apparatus there being

• (a) a first cooling means to cool said gas stream under pressure connected to provide a cooled stream under pressure;
• (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and expand it to a lower pressure, whereby said stream is further cooled;
• and
• (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into said volatile residue gas fraction and said relatively less volatile fraction;
• the improvement wherein said apparatus includes
• (1) first dividing means prior to said first cooling means to divide said gas stream into first and second streams;
• (2) second cooling means connected to said first dividing means to receive said first stream and cool it sufficiently to substantially condense it;
• (3) said first expansion means connected to said second cooling means, said first expansion means being adapted to receive said substantially condensed first stream and expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded substantially condensed first stream to said distillation column at an upper mid-column feed position;
• (4) said first cooling means connected to said first dividing means to receive said second stream and cool it under pressure sufficiently to partially condense it;
• (5) separating means connected to said first cooling means to receive said partially condensed second stream and separate it into a vapor stream and at least one liquid stream;
• (6) second dividing means connected to said separating means to receive said vapor stream and divide it into first and second portions;
• (7) third cooling means connected to said second dividing means to receive said first portion and cool it sufficiently to substantially condense it;
• (8) second expansion means connected to said third cooling means to receive said substantially condensed first portion and expand it to said lower pressure, said second expansion means being further connected to said distillation column to supply said expanded substantially condensed first portion to said distillation column at a top feed position;
• (9) third expansion means being connected to said second dividing means to receive said second portion and expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position below said upper mid-column feed position;
• (10) fourth expansion means connected to said separating means to receive at least a portion of said at least one liquid stream and expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a lower mid-column feed position below said mid-column feed position;
• and
• (11) control means adapted to regulate the quantities and temperatures of said feed streams to said distillation column 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.