Hydrocarbon gas processing

In a process for the separation of a gas containing methane, C.sub.2 components, C.sub.3 components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and C.sub.2 components and a relatively less volatile fraction containing a major portion of said C.sub.3 components and heavier components, in which process

• (a) said gas 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 fractionated at said lower pressure whereby the major portion of said C.sub.3 components and heavier components is recovered in said relatively less volatile fraction;
• the improvement wherein prior to cooling, said gas is divided into gaseous first and second streams and
• (1) said gaseous first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure;
• (2) said gaseous second stream is cooled under pressure and is thereafter expanded to said lower pressure;
• (3) the expanded cooled first stream is directed in heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column;
• (4) the distillation stream is cooled by said first stream sufficiently to partially condense it and said partially condensed distillation stream is separated thereby to provide said volatile residue gas and a reflux stream, said reflux stream is supplied to said distillation column at a top column feed position;
• (5) the warmed first stream is then supplied to said distillation column at a first mid-column feed position;
• (6) the expanded cooled second stream is supplied to said distillation column at a second mid-column feed position;
• and
• (7) the temperatures of said feeds to the column are effective to maintain column overhead temperature at a temperature whereby the major portion of said C.sub.3 components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

In a process for the separation of a gas containing methane, C.sub.2 components, C.sub.3 components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and C.sub.2 components and a relatively less volatile fraction containing a major portion of said C.sub.3 components and heavier components, in which process

• (a) said gas 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 fractionated at said lower pressure whereby the major portion of said C.sub.3 components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;
• the improvement 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;
• (2) said second stream is expanded to said lower pressure;
• (3) the expanded cooled first stream is directed in heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column;
• (4) the distillation stream is cooled by said first stream sufficiently to partially condense it and said partially condensed distillation stream is separated thereby to provide said volatile residue gas and a reflux stream, said reflux stream is supplied to said distillation column at a top column feed position;
• (5) the warmed first stream is then supplied to said column at a first mid-column feed position;
• (6) the expanded second stream is supplied to said distillation column at a second mid-column feed position;
• and
• (7) the temperatures of said feeds to the column are effective to maintain column overhead temperature at a temperature whereby the major portion of said C.sub.3 components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

In an apparatus for the separation of a gas containing methane, C.sub.2 components, C.sub.3 components and heavier hydrocarbons into a volatile residue gas fraction containing a major portion of said methane and C.sub.2 components and a relatively less volatile fraction containing a major portion of said C.sub.3 components and heavier components, in said apparatus there being

• (a) a first cooling means to cool said gas 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 to expand it to a lower pressure, whereby said stream is further cooled;
• and
• (c) a distillation column connected to said first expansion means to receive the further cooled stream therefrom;
• the improvement wherein said apparatus includes
• (1) first cooling means adapted to cool said feed gas under pressure sufficiently to partially condense it;
• (2) first separation means connected to said first cooling means to receive said partially condensed feed and to separate it into a vapor and a condensed stream;
• (3) dividing means connected to said first separation means to receive said vapor and to divide said vapor into first and second streams;
• (4) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
• (5) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure;
• (6) heat exchange means connected to said second expansion means to receive said expanded first stream and to heat it, said heat exchange means being further connected to said distillation column (a) at a first mid-column feed position to supply said heated first stream to said distillation column and (b) at a point to receive a distillation stream rising from fractionation stages of the distillation column and to cool and partially condense said distillation stream;
• said heat exchange means being further connected to second separation means;
• (7) said second separation means being connected to said heat exchange means to receive said partially condensed distillation stream and to separate it into said volatile residue gas fraction and a reflux stream, said second separation means being further connected to said distillation column to supply said reflux stream to the distillation column at a top column feed position;
• (8) first expansion means connected to said dividing means to receive said second stream and expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded stream to said column at a second mid-column feed position;
• (9) third expansion means connected to said first separation means to receive the condensed stream from said first separation means and to expand it to said lower pressure;
• said third expansion being further connected to said distillation column to supply said condensed stream to said column at a third mid-column feed position;
• and
• (10) control means adapted to regulate the temperatures of said first stream, said second stream, said reflux stream and said condensed stream to maintain column overhead temperature at a temperature whereby the major portion of said C.sub.3 components and heavier components is recovered in said relatively less volatile fraction.

In an apparatus for the separation of a feed gas containing methane, C.sub.2 components, C.sub.3 components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and C.sub.2 components and a relatively less volatile fraction containing a major portion of said C.sub.3 components and heavier components;

• in said apparatus there being
• (a) a first cooling means to cool said gas 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 to expand it to a lower pressure, whereby said stream is further cooled;
• and
• (c) a distillation column connected to said expansion means to receive the further cooled stream therefrom;
• the improvement wherein said apparatus includes
• (1) dividing means prior to said first cooling means to divide said feed gas into a first gaseous stream and a second gaseous stream;
• (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
• (3) second expansion means connected to said second cooling means to receive the substantially condensed first stream therefrom and to expand it to said lower pressure;
• (4) heat exchange means connected to said second expansion means to receive said expanded first stream and to heat it, said heat exchange means being further connected to said distillation column (a) at a first mid-column feed position to supply said heated first stream to said column and (b) at a point to receive a distillation stream rising from fractionation stages of the distillation column wherein said heat exchange means cools and partially condenses said distillation stream;
• said heat exchange means being further connected to separation means;
• (5) said separation means being connected to said heat exchange means to receive said partially condensed distillation stream and to separate it into said residue gas fraction and a reflux stream, said separation means being further connected to said distillation column to supply said reflux stream to the distillation colmn at a top column feed position;
• (6) said first cooling means being connected to said dividing means to receive said second stream and to cool it;
• (7) said first expansion means being connected to said first cooling means to receive said cooled second stream and to expand and further cool it;
• said first expansion means being further connected to said distillation column to supply said second stream to the column at a second mid-column feed position;
• and
• (8) control means adapted to regulate the temperatures of said first stream, said second stream and said reflux stream to maintain column overhead temperature at a temperature whereby the major portion of said C.sub.3 components and heavier components is recovered in said relatively less volatile fraction.

In an apparatus for the separation of a gas containing methane, C.sub.2 components, C.sub.3 components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and C.sub.2 components and a relatively less volatile fraction containing a major portion of said C.sub.3 components and heavier components;

• in said apparatus there being
• (a) a first cooling means to cool said gas undr 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 to expand it to a lower pressure, whereby said stream is further cooled;
• and
• (c) a distillation column connected to said expansion means to receive the further cooled stream therefrom;
• the improvement wherein said apparatus includes
• (1) dividing means after said first cooling means to divide said cooled stream into a first stream and a second stream;
• (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
• (3) second expansion means connected to said second cooling means to receive the substantially condensed first stream therefrom and to expand it to said lower pressure;
• (4) heat exchange means connected to said second expansion means to receive said expanded first stream and to heat it, said heat exchange means being further connected to said distillation column (a) at a first mid-column feed position to supply said heated first stream to said distillation column and (b) at a point to receive a distillation stream rising from fractionation stages of the distillation column wherein said heat exchange means cools and partially condenses said distillation stream;
• said heat exchange means being further connected to separation means;
• (5) said separation means being connected to said heat exchange means to receive said partially condensed distillation stream and to separate it into said volatile residue gas fraction and a reflux stream, said separation means being further connected to said distillation column to supply said reflux stream to the distillation column at a top column feed position;
• (6) said first expansion means being connected to said dividing means to receive said second stream and to expand and cool it;
• said first expansion means being further connected to said distillation column to supply said second stream to the column at a second mid-column feed position;
• and
• (7) control means adapted to regulate the temperatures of said first stream, said second stream and said reflux stream to maintain column overhead temperature at a temperature whereby the major portion of said C.sub.3 components and heavier components is recovered in said relatively less volatile fraction.