Hydrocarbon gas processing

• US 4,889,545 A
• Filed: 11/21/1988
• Issued: 12/26/1989
• Est. Priority Date: 11/21/1988
• Status: Expired due to Term

• Current Assignee: UOP Llc (Honeywell International Inc.)
• Original Assignee: Elcor Corporation
• Inventors: Hudson, Hank M., Wilkinson, John D., Campbell, Roy E.
• Primary Examiner(s): Capossela, Ronald C.
• Application Number:
  US07/275,102
• Time in Patent Office: 400 Days
• Field of Search: 62/11, 62/23, 62/24, 62/38, 62/39, 62/43
• US Class Current: 62/621
• CPC Class Codes: C07C 7/04 by distillation
• CPC Class Codes: F25J 2200/02 in a single pressure main column system
• CPC Class Codes: F25J 2200/72 Refluxing the column with at least a part of the totally condensed overhead gas
• CPC Class Codes: F25J 2205/04 in the feed line, i.e. upstream of the fractionation step
• CPC Class Codes: F25J 2210/06 Splitting of the feed stream, e.g. for treating or cooling in different ways
• CPC Class Codes: F25J 2210/12 Refinery or petrochemical off-gas
• CPC Class Codes: F25J 2230/08 Cold compressor, i.e. suction of the gas at cryogenic temperature and generally without afterstage-cooler
• CPC Class Codes: F25J 2240/02 Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
• CPC Class Codes: F25J 2240/30 Dynamic liquid or hydraulic expansion with extraction of work, e.g. single phase or two-phase turbine
• CPC Class Codes: F25J 2270/02 Internal refrigeration with liquid vaporising loop
• CPC Class Codes: F25J 3/0209 Natural gas or substitute natural gas
• CPC Class Codes: F25J 3/0219 Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
• CPC Class Codes: F25J 3/0233 separation of CnHm with 1 carbon atom or more
• CPC Class Codes: F25J 3/0238 separation of CnHm with 2 carbon atoms or more
• CPC Class Codes: F25J 3/0242 separation of CnHm with 3 carbon atoms or more

Abstract

A process for the recovery of ethane, ethylene, propane, propylene and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. The stream is divided into first and second streams. The first stream is cooled to condense substantially all of it and is thereafter expanded to the fractionation tower pressure. After expansion, the cooled first stream is directed in heat exchange relation with a compressed recycle portion of the fractionation tower overhead. The warmed first stream is then supplied to the fractionation tower at a first mid-column feed position. The second stream is expanded to the tower pressure and is then supplied to the column at a second mid-column feed position. The recycle stream is cooled by the first stream sufficiently to substantially condense it. The substantially condensed recycle stream is then expanded to the pressure of the distillation column and supplied to the column at a top column feed position. The pressure of the recycle stream and the quantities and temperatures of the feeds to the column are effective to maintain the column overhead temperature at a temperature whereby the major portion of the desired components is recovered.

Claims

1. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile reaction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(1) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) said gaseous first stream is combined with at least a portion of said condensed stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) the expanded cooled combined stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said combined stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) said compressed recycle stream is cooled by said expanded cooled stream sufficiently to substantially condense it;

(7) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(8) said gaseous second stream is expanded to said lower pressure and is supplied to said distillation column at a second mid-column feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

17. The improvement according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 wherein said recycle stream is heated prior to compression.

18. The improvement according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

19. The improvement according to claim 1, 2, 3, 4, 5 or 6 wherein at least a portion of said condensed stream is expanded to said lower pressure and then supplied to said distillation column at a third mid-column feed position.

20. The improvement according to claim 1, 2, 3, 4, 5 or 6 wherein at least a portion of said condensed stream is expanded to said lower pressure, heated and then supplied to said distillation column at a third mid-column feed position.

21. The improvement according to claim 19 wherein said recycle stream is heated prior to compression.

22. The improvement according to claim 20 wherein said recycle stream is heated prior to compression.

23. The improvement according to claim 19 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

24. The improvement according to claim 20 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

25. The improvement according to claim 1 or 2 wherein at least portions of two or more of said combined stream, said second stream and said condensed stream are combined to form a second combined stream and said second combined stream is supplied to said column at a mid-column feed position.

26. The improvement according to claim 25 wherein said recycle stream is heated prior to compression.

27. The improvement according to claim 25 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

55. The improvement according to claim 1, 2, 7, 8, 13, 14, 15 or 16 wherein said second stream is heated after expansion to said lower pressure.

56. The improvement according to claim 55 wherein said recycle stream is heated prior to compression.

57. The improvement according to claim 55 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

2. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(2) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) said gaseous first stream is combined with at least a portion of said condensed stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) the expanded cooled combined stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said combined stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) said compressed recycle stream is cooled by said expanded cooled combined stream sufficiently to substantially condense it;

(7) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(8) said gaseous second stream is expanded to said lower pressure and is supplied to said distillation column at a second mid-column feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

3. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ components and heavier hydrocarbon 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 second stream is cooled under pressure sufficiently to partially condense it;

(2) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(3) said gaseous first stream is cooled and then combined with at least a portion of said condensed stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) the expanded cooled combined stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said combined stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) said compressed recycle stream is cooled by said expanded cooled combined stream sufficiently to substantially condense it;

(7) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain the tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

28. The improvement according to claim 3, 4, 5 or 6 wherein at least portions of two or more of said combined stream, said vapor stream and said condensed stream are combined to form a second combined stream and said second combined stream is supplied to said column at a mid-column feed position.

29. The improvement according to claim 28 wherein said recycle stream is heated prior to compression.

30. The improvement according to claim 28 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

4. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ components and heavier hydrocarbon 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 second stream is cooled under pressure sufficiently to partially condense it;

(2) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(3) said gaseous first stream is cooled and then combined with at least a portion of said condensed stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) the expanded cooled combined stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said combined stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) said compressed recycle stream is cooled by said expanded cooled combined stream sufficiently to substantially condense it;

(7) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain the tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

5. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ 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 stream; and

(1) said second stream is cooled sufficiently to partially condense it;

(2) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(3) said first stream is combined with at least a portion of said condensed stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) said expanded cooled combined stream is directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said combined stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) said compressed recycle stream is cooled by said expanded cooled combined stream sufficiently to substantially condense it;

(7) said substantially condensed compressed recycle stream is expanded to said lower pressure and thereafter supplied to said fractionation tower at a top feed position;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

6. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ 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 second stream is cooled sufficiently to partially condense it;

(2) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(3) said first stream is combined with at least a portion of said condensed stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) said expanded cooled combined stream is directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said combined stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) said compressed recycle stream is cooled by said expanded cooled combined stream sufficiently to substantially condense it;

(7) said substantially condensed compressed recycle stream is expanded to said lower pressure and thereafter supplied to said fractionation tower at a top feed position;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

7. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(1) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) said gaseous first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) the expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) the compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(7) the substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(8) the gaseous second stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;

(9) at least a portion of said condensed stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

31. The improvement according to claim 7 or 8 wherein at least portions of two or more of said first stream, said second stream and said condensed stream are combined to form a combined stream and said combined stream is supplied to said column at a mid-column feed position.

32. The improvement according to claim 31 wherein said recycle stream is heated prior to compression.

33. The improvement according to claim 31 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

8. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(1) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) said gaseous first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;

(4) the expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(5) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(6) the compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(7) the substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(8) the gaseous second stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;

(9) at least a portion of said condensed stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

9. In a preocess for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ components and heavier hydrocarbon 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 whereby it is further cooled;

(2) the expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(6) said gaseous second stream is cooled under pressure sufficiently to partially condense it;

(7) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;

(9) at least a portion of said condensed stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain the tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

10. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ components and heavier hydrocarbon 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 whereby it is further cooled;

(2) the expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(6) said gaseous second stream is cooled under pressure sufficiently to partially condense it;

(7) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;

(9) at least a portion of said condensed stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain the tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

34. The improvement according to claim 9, 10, 11 or 12 wherein at least portions of two or more of said first stream, said vapor stream and said condensed stream are combined to form a combined stream and said combined stream is supplied to said column at a mid-column feed position.

35. The improvement according to claim 34 wherein said recycle stream is heated prior to compression.

36. The improvement according to claim 34 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

40. The improvement according to claim 7, 8, 9, 10, 11 or 12 wherein,

(a) said condensed stream is cooled prior to said expansion and then divided into first and second liquid portions;

(b) said first liquid portion is expanded to said lower pressure and supplied to said column at a mid-column feed position; and

(c) said second liquid portion is expanded to said lower pressure and supplied to said column at a higher mid-column feed position.

41. The improvement according to claim 40 wherein said recycle stream is heated prior to compression.

42. The improvement according to claim 40 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

43. The improvement according to claim 40 wherein

(a) at least part of said second liquid portion is combined with said first stream to form a combined stream and said combined stream is directed in heat exchange relation with said compressed recycle stream;

(b) the remainder of said second liquid portion is expanded to said lower pressure and supplied to said column at another mid-column feed position.

44. The improvement according to claim 43 wherein said recycle stream is heated prior to compression.

45. The improvement according to claim 43 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

46. The improvement according to claim 40 wherein said first liquid portion is expanded, directed in heat exchange relation with said condensed stream and is then supplied to said column at a mid-column feed position.

47. The improvement according to claim 46 wherein said recycle stream is heated prior to compression.

48. The improvement according to claim 46 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

49. The improvement according to claim 40 wherein said second liquid portion is expanded to said lower pressure and at least part of said expanded second liquid portion is combined with said expanded cooled first stream to form a combined stream and said combined stream is directed in heat exchange relation with said compressed recycle stream.

50. The improvement according to claim 49 wherein said recycle stream is heated prior to compression.

51. The improvement according to claim 49 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

52. The improvement according to claim 7, 8, 9, 10, 11 or 12 wherein said expanded condensed stream is heated prior to being supplied to said distillation column.

53. The improvement according to claim 52 wherein said recycle stream is heated prior to compression.

54. The improvement according to claim 52 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

58. The improvement according to claim 3, 4, 5, 6, 9, 10, 11 or 12 wherein said vapor stream is heated after expansion to said lower pressure.

59. The improvement according to claim 58 wherein said recycle stream is heated prior to compression.

60. The improvement according to claim 58 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

11. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ 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 whereby it is further cooled;

(2) said expanded cooled first stream is directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and thereafter supplied to said fractionation tower at a top feed position;

(6) said second stream is cooled sufficiently to partially condense it;

(7) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;

(9) at least a portion of said condensed stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

12. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ 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 whereby it is further cooled;

(2) said expanded cooled first stream is directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and thereafter supplied to said fractionation tower at a top feed position;

(6) said second stream is cooled sufficiently to partially condense it;

(7) said partially condensed second stream is separated thereby to provide a vapor stream and a condensed stream;

(8) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;

(9) at least a portion of said condensed stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

13. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ 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 whereby it is further cooled;

(2) said expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(6) said second stream is expanded to said lower pressure and is supplied to said distillation column at a second mid-column feed position; and

(7) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

37. The improvement according to claim 13, 14, 15 or 16 wherein at least portions of said first stream and said second stream are combined to form a combined stream and said combined stream is supplied to said column at a mid-column feed position.

38. The improvement according to claim 37 wherein said recycle stream is heated prior to compression.

39. The improvement according to claim 37 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

14. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ 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 whereby it is further cooled;

(2) said expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(6) said second stream is expanded to said lower pressure and is supplied to said distillation column at a second mid-column feed position; and

(7) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

15. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ components and heavier hydrocarbon 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 whereby it is further cooled;

(2) the expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fraction and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(6) said gaseous second stream is cooled under pressure and then expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position; and

(7) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain the tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

16. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ components and heavier hydrocarbon 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 whereby it is further cooled;

(2) the expanded cooled first stream is then directed in heat exchange relation with a warmer compressed recycle portion of a distillation stream which rises in a fractionation tower;

the distillation stream is withdrawn from an upper region of said tower and is thereafter divided into said volatile residue gas fracton and said recycle stream;

(3) said first stream is thereafter supplied at a first mid-column feed position to a distillation column in a lower region of the fractionation tower;

(4) said compressed recycle stream is cooled by said expanded cooled first stream sufficiently to substantially condense it;

(5) said substantially condensed compressed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position;

(6) said gaseous second stream is cooled under pressure and then expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position; and

(7) the pressure of said compressed recycle stream and the quantities and temperatures of said feeds to the column are effective to maintain the tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction.

61. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(1) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) said gaseous first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure and supplied at a first mid-column feed position to a distillation column in a lower region of a fractionation tower;

(4) said gaseous second stream is expanded to said lower pressure and is then supplied to said distillation column at a second mid-column feed position;

(5) at least a portion of said condensed stream is expanded to said lower pressure and is then supplied to said distillation column at a third mid-column feed position;

(6) a distillation stream is withdrawn from an upper region of said fractionation tower and is thereafter divided into said volatile residue gas fraction and a recycle stream;

(7) a cold liquid stream is withdrawn from said distillation column at a mid-column position;

(8) said recycle stream is compressed and directed in heat exchange relation with said cold liquid stream whereby said compressed recycle stream is cooled by said cold liquid stream sufficiently to substantially condense it and said cold liquid stream is heated and partially vaporized;

(9) the substantially condensed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperature of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier components is recovered in said relatively less volatile fraction.

65. The improvement according to claim 61, 62, 63 or 64 wherein said recycle stream is heated prior to compression.

66. The improvement according to claim 61, 62, 63 or 64 wherein said distillation stream is heated prior to being divided into said volatile residue gas fraction and said recycle stream.

62. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(1) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) said gaseous first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure and supplied at a first mid-column feed position to a distillation column in a lower region of a fractionation tower;

(4) said gaseous second stream is expanded to said lower pressure and is then supplied to said distillation column at a second mid-column feed position;

(5) at least a portion of said condensed stream is expanded to said lower pressure and is then supplied to said distillation column at a third mid-column feed position;

(6) a distillation stream is withdrawn from an upper region of said fractionation tower and is thereafter divided into said volatile residue gas fraction and a recycle stream;

(7) a cold liquid stream is withdrawn from said distillation column at a mid-column position;

(8) said recycle stream is compressed and directed in heat exchange relation with said cold liquid stream whereby said compressed recycle stream is cooled by said cold liquid stream sufficiently to substantially condense it and said cold liquid stream is heated and partially vaporized;

(9) the substantially condensed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position; and

(10) the pressure of said compressed recycle stream and the quantities and temperature of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier components is recovered in said relatively less volatile fraction.

63. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 C₂ components, C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(1) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) at least a portion of said condensed stream is combined with said gaseous first stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure and supplied at a first mid-column feed position to a distillation column in a lower region of a fractionation tower;

(4) said gaseous second stream is expanded to said lower pressure and is then supplied to said distillation column at a second mid-column feed position;

(5) a distillation stream is withdrawn from an upper region of said fractionation tower and is thereafter divided into said volatile residue gas fraction and a recycle stream;

(6) a cold liquid stream is withdrawn from said distillation column at a mid-column position;

(7) said recycle stream is compressed and directed in heat exchange relation with said cold liquid stream whereby said compressed recycle stream is cooled by said cold liquid stream sufficiently to substantially condense it and said cold liquid stream is heated and partially vaporized;

(8) the substantially condensed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperature of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier components is recovered in said relatively less volatile fraction.

64. In a process for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 C₃ components and heavier hydrocarbon components is recovered in said relatively less volatile fraction;

the improvement wherein said gas is cooled sufficiently to partially condense it; and

(1) said partially condensed gas is separated thereby to provide a vapor stream and a condensed stream;

(2) said vapor stream is thereafter divided into gaseous first and second streams;

(3) at least a portion of said condensed stream is combined with said gaseous first stream to form a combined stream and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure and supplied at a first mid-column feed position to a distillation column in a lower region of a fractionation tower;

(4) said gaseous second stream is expanded to said lower pressure and is then supplied to said distillation column at a second mid-column feed position;

(5) a distillation stream is withdrawn from an upper region of said fractionation tower and is thereafter divided into said volatile residue gas fraction and a recycle stream;

`(6) a cold liquid stream is withdrawn from said distillation column at a mid-column position;

(7) said recycle stream is compressed and directed in heat exchange relation with said cold liquid stream whereby said compressed recycle stream is cooled by said cold liquid stream sufficiently to substantially condense it and said cold liquid stream is heated and partially vaporized;

(8) the substantially condensed recycle stream is expanded to said lower pressure and supplied to said fractionation tower at a top feed position; and

(9) the pressure of said compressed recycle stream and the quantities and temperature of said feeds to the column are effective to maintain tower overhead temperature at a temperature whereby the major portion of said C₃ components and heavier components is recovered in said relatively less volatile fraction.

67. In an apparatus for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 fractionation tower 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) 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) first dividing means connected to said separation means to receive said vapor and to divide said vapor into first and second streams;

(4) combining means connected to combine said condensed stream and said first stream into a combined stream;

(5) second cooling means connected to said combining means to receive said combined stream and to cool it sufficiently to substantially condense it;

(6) second expansion means connected to said second cooling means to receive said substantially condensed combined stream and to expand it to said lower pressure;

(7) heat exchange means connected to said second expansion means to receive said expanded combined stream and to heat it, said heat exchange means further connected to compressing means to receive a compressed recycle portion of a distillation stream which rises in the fractionation tower, wherein said heat exchange means cools and substantially condenses said compressed recycle stream;

said heat exchange means being further connected to a distillation column in a lower region of the fractionation tower to supply said expanded combined stream to said distillation column at a first mid-column feed position;

said heat exchange means being further connected to a third expansion means;

(8) said third expansion means being connected to said heat exchange means to receive said substantially condensed compressed recycle stream and expand it to said lower pressure, said third expansion means being further connected to said fractionation tower to supply said expanded condensed recycle stream to the tower at a top feed position;

(9) second dividing means connected to said fractionation tower to receive said distillation stream and to divide it into said volatile residue gas fraction and said recycle stream;

(10) compressing means connected to said dividing means to receive said recycle stream and to compress it, said compressing means being further connected to said heat exchange means;

(11) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded second stream to said column at a second mid-column feed position; and

(12) control means adapted to regulate the pressure of said compressed recycle stream and the quantities and temperatures of said combined stream, said second stream and said recycle stream to maintain column overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier components is recovered in said relatively less volatile fraction.

68. In an apparatus for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 fractionation tower 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) 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) first dividing means connected to said separation means to receive said vapor and to divide said vapor into first and second streams;

(4) combining means connected to combine said condensed stream and said first stream into a combined stream;

(5) second cooling means connected to said combining means to receive said combined stream and to cool it sufficiently to substantially condense it;

(6) second expansion means connected to said second cooling means to receive said substantially condensed combined stream and to expand it to said lower pressure;

(7) heat exchange means connected to said second expansion means to receive said expanded combined stream and to heat it, said heat exchange means further connected to compressing means to receive a compressed recycle portion of a distillation stream which rises in the fractionation tower, wherein said heat exchange means cools and substantially condenses said compressed recycle stream;

said heat exchange means having further connected to a distillation column in a lower region of the fractionation tower to supply said expanded combined stream to said distillation column at a first mid-column feed position;

said heat exchange means being further connected to a third expansion means;

(8) said third expansion means being connected to said heat exchange means to receive said substantially condensed compressed recycle stream and expand it to said lower pressure, said third expansion means being further connected to said fractionation tower to supply said expanded condensed recycle stream to the tower at a top feed position;

(9) second dividing means connected to said fractionation tower to receive said distillation stream and to divide it into said volatile residue gas fraction and said recycle stream;

(10) compressing means connected to said dividing means to receive said recycle stream and to compress it, said compressing means being further connected to said heat exchange means;

(11) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded second stream to said column at a second mid-column feed position; and

(12) control means adapted to regulate the pressure of said compressed recycle stream and the quantities and temperatures of said combined stream, said second stream and said recycle stream to maintain column overhead temperature at a temperature whereby the major portion of said C₃ components and heavier components is recovered in said relatively less volatile fraction.

69. In an apparatus for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 fractionation tower connected to said expansion means to receive the further cooled stream therefrom;

the improvement wherein said apparatus includes

(1) first 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 compressing means to receive a compressed recycle portion of a distillation stream which rises in the fractionation tower, wherein said heat exchange means cools and substantially condenses said compressed recycle stream;

said heat exchange means being further connected to a distillation column in a lower region of the fractionation tower to supply said heated first stream to the column at a first mid-column feed position;

said heat exchange means being further connected to a third expansion means;

(5) said third expansion means being connected to said heat exchange means to receive said substantially condensed recycle stream and to expand it to said lower pressure, said third expansion means being further connected to said fractionation tower to supply said expanded condensed recycle stream to the tower at a top feed position;

(6) second dividing means connected to said fractionation tower to receive said distillation stream and to divide it into said volatile residue gas fraction and said recycle stream;

(7) compressing means connected to said dividing means to receive said recycle stream and to compress it, said compressing means being further connected to said heat exchange means;

(8) said first cooling means being connected to said first dividing means to receive said second stream and to cool it;

(9) 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

(10) control means adapted to regulate the pressure of said compressed recycle stream and the quantities and temperatures of said first stream, said second stream and said recycle stream to maintain column overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier components is recovered in said relatively less volatile fraction.

70. In an apparatus for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 fractionation tower connected to said expansion means to receive the further cooled stream therefrom;

the improvement wherein said apparatus includes

(1) first 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 compressing means to receive a compressed recycle portion of a distillation stream which rises in the fractionation tower, wherein said heat exchange means cools and substantially condenses said compressed recycle stream;

said heat exchange means being further connected to a distillation column in a lower region of the fractionation tower to supply said heated first stream to the column at a first mid-column feed position;

said heat exchange means being further connected to a third expansion means;

(5) said third expansion means being connected to said heat exchange means to receive said substantially condensed recycle stream and to expand it to said lower pressure, said third expansion means being further connected to said fractionation tower to supply said expanded condensed recycle stream to the tower at a top feed position;

(6) second dividing means connected to said fractionation tower to receive said distillation stream and to divide it into said volatile residue gas fraction and said recycle stream;

(7compressing means connected to said dividing means to receive said recycle stream and to compress it, said compressing means being further connected to said heat exchange means;

(8) said first cooling means being connected to said first dividing means to receive said second stream and to cool it;

(9) 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

(10) control means adapted to regulate the pressure of said compressed recycle stream and the quantities and temperatures of said first stream, said second stream and said recycle stream to maintain column overhead temperature at a temperature whereby the major portion of said C₃ components and heavier components is recovered in said relatively less volatile fraction.

71. In an apparatus for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile fraction containing a major portion of said C₂ components, C₃ 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 fractionation tower connected to said first expansion means to receive the further cooled stream therefrom;

the improvement wherein said apparatus includes

(1) first 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 first 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 compressing means to receive a compressed recycle portion of a distillation stream which rises in the fractionation tower, wherein said heat exchange means cools and substantially condenses said compressed recycle stream;

said heat exchange means being further connected to a distillation column in a lower region of the fractionation tower to supply said heated expanded first stream to said distillation column at a first mid-column feed position;

said heat exchange means being further connected to a third expansion means;

(5) said third expansion means connected to said heat exchange means to receive said substantially condensed recycle stream therefrom and expand it to said lower pressure, said third expansion means being further connected to said fractionation tower to supply said expanded recycle stream to said tower at a top feed position;

(6) second dividing means connected to said fractionation tower to receive said distillation stream and to divide into said volatile residue gas fraction and said recycle stream;

(7) compressing means connected to said second dividing means to receive said recycle stream and compress it, said compressing means being further connected to said heat exchange means;

(8) said first expansion means being connected to said first 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

(9) control means adapted to regulate the pressure of said compressed recycle stream and the quantities and temperatures of said first stream, said second stream and said recycle stream to maintain column overhead temperature at a temperature whereby the major portion of said C₂ components, C₃ components and heavier components is recovered in said relatively less volatile fraction.

72. In an apparatus for the separation of a gas containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and said C₂ components and a relatively less volatile fraction containing a major portion of said C₃ 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 fractionation tower connected to said first expansion means to receive the further cooled stream therefrom;

the improvement wherein said apparatus includes

(1) first 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 first 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 compressing means to receive a compressed recycle portion of a distillation stream which rises in the fractionation tower, wherein said heat exchange means cools and substantially condenses said compressed recycle stream;

said heat exchange means being further connected to a distillation column in a lower region of the fractonation tower to supply said heated expanded first stream to said distillation column at a first mid-column feed position;

said heat exchange means being further connected to a third expansion means;

(5) said third expansion means connected to said heat exchange means to receive said substantially condensed recycle stream therefrom and expand it to said lower pressure, said third expansion means being further connected to said fractionation tower to supply said expanded recycle stream to said tower at a top feed position;

(6) second dividing means connected to said fractionation tower to receive said distillation stream and to divide into said volatile residue gas fraction and said recycle stream;

(7) compressing means connected to said second dividing means to receive said recycle stream and compress it, said compressing means being further connected to said heat exchange means;

(8) said first expansion means being connected to said first 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

(9) control means adapted to regulate the pressure of said compressed recycle stream and the quantities and temperatures of said first stream, said second stream and said recycle stream to maintain column overhead temperature at a temperature whereby the major portion of said C₃ components and heavier components is recovered in said relatively less volatile fraction.