Hydrocarbon gas processing

• US 5,890,378 A
• Filed: 03/31/1998
• Issued: 04/06/1999
• Est. Priority Date: 04/21/1997
• Status: Expired due to Term

• Current Assignee: UOP Llc (Honeywell International Inc.)
• Original Assignee: Elcor Corporation
• Inventors: Rambo, C. L., Hudson, Hank M., Wilkinson, John D., Pierce, Michael C.
• Primary Examiner(s): Capossela, Ronald
• Application Number:
  US09/052,845
• Time in Patent Office: 371 Days
• Field of Search: 62/621, 62/630
• US Class Current: 62/621
• CPC Class Codes: C10G 5/06 by cooling or compressing
• CPC Class Codes: C10L 3/06 Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04 liquefying by pressure and cold treatment F25J
• CPC Class Codes: F25J 2200/02 in a single pressure main column system
• CPC Class Codes: F25J 2200/04 in a dual pressure main column system
• CPC Class Codes: F25J 2200/70 Refluxing the column with a condensed part of the feed stream, i.e. fractionator top is stripped or self-rectified
• CPC Class Codes: F25J 2200/78 Refluxing the column with a liquid stream originating from an upstream or downstream fractionator column
• CPC Class Codes: F25J 2205/02 using simple phase separation in a vessel or drum
• 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 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 2270/02 Internal refrigeration with liquid vaporising loop
• CPC Class Codes: F25J 2270/12 External refrigeration with liquid vaporising loop
• CPC Class Codes: F25J 2270/60 Closed external refrigeration cycle with single component refrigerant [SCR], e.g. C1-, C2- or C3-hydrocarbons
• CPC Class Codes: F25J 2280/02 Control in general, load changes, different modes ("runs"), measurements
• CPC Class Codes: F25J 2290/40 Vertical layout or arrangement of cold equipments within in the cold box, e.g. columns, condensers, heat exchangers etc.
• CPC Class Codes: F25J 2290/80 Retrofitting, revamping or debottlenecking of existing plant
• CPC Class Codes: F25J 3/0209 Natural gas or substitute natural gas
• 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, and the second stream is cooled and expanded to a lower pressure and supplied to a contacting device. The first stream is cooled to condense substantially all of it, expanded to the lower pressure, and then used to cool a warmer distillation stream from a distillation column to at least partially condense the distillation stream. At least a portion of the partially condensed distillation stream is directed to the contacting device to intimately contact the expanded second stream, the resulting vapors and liquids are separated from the contacting device, and these liquids are supplied to the distillation column. The quantities and temperatures of the feeds to the contacting device and the distillation column are effective to maintain the overhead temperatures of the contacting device and the distillation column at temperatures whereby the major portion of the desired components is recovered.

Claims

1. In a process for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in which process

(a) said gas stream is divided into gaseous first and second streams;

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

(c) said gaseous second stream is cooled under pressure and is thereafter expanded to said lower pressure; and

(d) said cooled expanded first and second streams are fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;

the improvement wherein

(1) said expanded cooled first stream is directed into heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) at least a portion of said cooled expanded second stream is intimately contacted with at least a portion of said at least partially condensed distillation stream in a contacting device containing at least a fractional theoretical separation stage, and thereafter the vapors and liquids from said contacting device are separated;

(3) said liquids thereby recovered are supplied to said distillation column as a liquid feed thereto;

(4) said vapors thereby recovered are directed into heat exchange relation with said gaseous first stream thereby to heat said vapors and supply said cooling of step (b), whereupon said heated vapors are thereafter discharged as said volatile residue gas fraction; and

(5) the quantities and temperatures of said feed streams to said contacting device and said distillation column are effective to maintain the overhead temperatures of said contacting device and said distillation column at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

7. The improvement according to claims 1, 2, 3, 4, 5, or 6 wherein at least a portion of said liquids separated from said contacting device are heated before being supplied to said distillation column as a feed thereto.

8. The improvement according to claims 1, 2, 3, 4, or 5 wherein

(a) vapor is separated from said at least partially condensed distillation stream before entering said contacting device, forming a residual vapor stream;

and

(b) said residual vapor stream is combined with said vapors separated from said contacting device to form said volatile residue gas fraction, whereupon said volatile residue gas fraction is directed into heat exchange relation with said gaseous first stream thereby to heat said volatile residue gas fraction and supply said cooling of said gaseous first stream.

2. In a process for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in which process

(a) said gas stream is cooled under pressure and then divided into gaseous first and second streams;

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

(c) said gaseous second stream is expanded to said lower pressure; and

(d) said cooled expanded first stream and said expanded second stream are fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;

the improvement wherein

(1) said expanded cooled first stream is directed into heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) at least a portion of said expanded second stream is intimately contacted with at least a portion of said at least partially condensed distillation stream in a contacting device containing at least a fractional theoretical separation stage, and thereafter the vapors and liquids from said contacting device are separated;

(3) said liquids thereby recovered are supplied to said distillation column as a liquid feed thereto;

(4) said vapors thereby recovered are directed into heat exchange relation with said gaseous first stream thereby to heat said vapors and supply said cooling of step (b), whereupon said heated vapors are thereafter discharged as said volatile residue gas fraction; and

(5) the quantities and temperatures of said feed streams to said contacting device and said distillation column are effective to maintain the overhead temperatures of said contacting device and said distillation column at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

3. In a process for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in which process

(a) said gas stream is divided into gaseous first and second streams;

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

(c) said gaseous second stream is cooled under pressure sufficiently to partially condense it and separated thereby to provide a vapor stream and a condensed stream;

(d) said vapor stream is expanded to said lower pressure;

(e) said condensed stream is expanded to said lower pressure; and

(f) said cooled expanded first stream, said expanded vapor stream, and said expanded condensed stream are fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;

the improvement wherein

(1) said expanded cooled first stream is directed into heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) at least a portion of said expanded vapor stream is intimately contacted with at least a portion of said at least partially condensed distillation stream in a contacting device containing at least a fractional theoretical separation stage, and thereafter the vapors and liquids from said contacting device are separated;

(3) said liquids thereby recovered are supplied to said distillation column as a liquid feed thereto;

(4) said vapors thereby recovered are directed into heat exchange relation with said gaseous first stream thereby to heat said vapors and supply said cooling of step (b), whereupon said heated vapors are thereafter discharged as said volatile residue gas fraction; and

(5) the quantities and temperatures of said feed streams to said contacting device and said distillation column are effective to maintain the overhead temperatures of said contacting device and said distillation column at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

4. In a process for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in which process

(a) said gas stream is cooled under pressure and then divided into gaseous first and second streams;

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

(c) said gaseous second stream is cooled under pressure sufficiently to partially condense it and separated thereby to provide a vapor stream and a condensed stream;

(d) said vapor stream is expanded to said lower pressure;

(e) said condensed stream is expanded to said lower pressure; and

(f) said cooled expanded first stream, said expanded vapor stream, and said expanded condensed stream are fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;

the improvement wherein

(1) said expanded cooled first stream is directed into heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) at least a portion of said expanded vapor stream is intimately contacted with at least a portion of said at least partially condensed distillation stream in a contacting device containing at least a fractional theoretical separation stage, and thereafter the vapors and liquids from said contacting device are separated;

(3) said liquids thereby recovered are supplied to said distillation column as a liquid feed thereto;

(4) said vapors thereby recovered are directed into heat exchange relation with said gaseous first stream thereby to heat said vapors and supply said cooling of step (b), whereupon said heated vapors are thereafter discharged as said volatile residue gas fraction; and

(5) the quantities and temperatures of said feed streams to said contacting device and said distillation column are effective to maintain the overhead temperatures of said contacting device and said distillation column at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

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

(a) said gas stream is cooled under pressure sufficiently to partially condense it and separated thereby to provide a vapor stream and a condensed stream;

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

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

(d) said gaseous second stream is expanded to said lower pressure;

(e) said condensed stream is expanded to said lower pressure; and

(f) said cooled expanded first stream, said expanded second stream, and said expanded condensed stream are fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;

the improvement wherein

(1) said expanded cooled first stream is directed into heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) at least a portion of said expanded second stream is intimately contacted with at least a portion of said at least partially condensed distillation stream in a contacting device containing at least a fractional theoretical separation stage, and thereafter the vapors and liquids from said contacting device are separated;

(3) said liquids thereby recovered are supplied to said distillation column as a liquid feed thereto;

(4) said vapors thereby recovered are directed into heat exchange relation with said gaseous first stream thereby to heat said vapors and supply said cooling of step (c), whereupon said heated vapors are thereafter discharged as said volatile residue gas fraction; and

(5) the quantities and temperatures of said feed streams to said contacting device and said distillation column are effective to maintain the overhead temperatures of said contacting device and said distillation column at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

6. In a process for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in which process

(a) said gas stream is cooled under pressure sufficiently to partially condense it and separated thereby to provide a vapor stream and a condensed stream;

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

(c) said gaseous first stream is combined with at least a portion of said condensed stream to form a combined stream;

(d) said combined stream is cooled under pressure to condense substantially all of it and is thereafter expanded to a lower pressure whereby it is further cooled;

(e) said gaseous second stream is expanded to said lower pressure; and

(f) said cooled expanded combined stream, said expanded second stream, and any remaining portion of said condensed stream are fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;

the improvement wherein

(1) said expanded cooled combined stream is directed into heat exchange relation with a warmer distillation stream which rises from fractionation stages of a distillation column, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) at least a portion of said expanded second stream is intimately contacted with at least a portion of said at least partially condensed distillation stream in a contacting device containing at least a fractional theoretical separation stage, and thereafter the vapors and liquids from said contacting device are separated;

(3) said liquids thereby recovered are supplied to said distillation column as a liquid feed thereto;

(4) said vapors thereby recovered are directed into heat exchange relation with said combined stream thereby to heat said vapors and supply said cooling of step (d), whereupon said heated vapors are thereafter discharged as said volatile residue gas fraction; and

(5) the quantities and temperatures of said feed streams to said contacting device and said distillation column are effective to maintain the overhead temperatures of said contacting device and said distillation column at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

9. The improvement according to claim 6 wherein

(a) vapor is separated from said at least partially condensed distillation stream before entering said contacting device, forming a residual vapor stream;

and

(b) said residual vapor stream is combined with said vapors separated from said contacting device to form said volatile residue gas fraction, whereupon said volatile residue gas fraction is directed into heat exchange relation with said combined stream thereby to heat said volatile residue gas fraction and supply said cooling of said combined stream.

10. In an apparatus for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in said apparatus there being

(a) a dividing means to divide said gas stream into gaseous first and second streams;

(b) a first heat exchange means connected to said dividing means to receive said gaseous first stream and to cool it under pressure sufficiently to substantially condense it;

(c) a first expansion means connected to said first heat exchange means to receive said substantially condensed first stream and to expand it to a lower pressure, whereby said stream is further cooled;

(d) a cooling means connected to said dividing means to receive said gaseous second stream and to cool it under pressure;

(e) a second expansion means connected to said cooling means to receive said cooled second stream and to expand it to said lower pressure; and

(f) a fractionation tower connected to said first expansion means and said second expansion means to receive said expanded streams therefrom;

the improvement wherein said apparatus includes

(1) a second heat exchange means connected to said first expansion means to receive said expanded cooled first stream, said second heat exchange means being further connected to said fractionation tower to receive a warmer distillation stream which rises from fractionation stages of a distillation column in said fractionation tower, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) a contacting and separating means connected to receive at least a portion of said at least partially condensed distillation stream and at least a portion of said cooled expanded second stream wherein said streams are commingled in at least one contacting device, said contacting and separating means including separating means to separate the vapor and liquid after contact in said contacting device to form a vapor stream and a liquid stream, said contacting and separating means being further connected to supply said liquid stream to said distillation column in said fractionation tower as a liquid feed thereto;

(3) said contacting and separating means being further connected to supply said vapor stream to said first heat exchange means to heat said vapor stream and thereby supply the cooling of step (b), whereupon said heated vapor stream is thereafter discharged as said volatile residue gas fraction; and

(4) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means and said fractionation tower to maintain the overhead temperatures of said contacting and separating means and said fractionation tower at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

16. The improvement according to claims 10, 11, 12, 13, 14, or 15 wherein the apparatus includes a heating means connected to said contacting and separating means to receive at least a portion of said liquid stream separated therefrom and heat it, said heating means being further connected to supply said heated stream to said distillation column in said fractionation tower as a feed thereto.

17. The improvement according to claims 10 or 11 wherein the apparatus includes

(a) a separation means connected to said second heat exchange means to receive said at least partially condensed distillation stream and separate it thereby to form a residual vapor stream and a liquid reflux stream, said separation means being further connected to supply said liquid reflux stream to said contacting and separating means;

(b) a combining means connected to said separation means to receive said residual vapor stream, said combining means being further connected to said contacting and separating means to receive said vapor stream separated therefrom and combine it with said residual vapor stream to form said volatile residue gas fraction; and

(c) said combining means being further connected to supply said volatile residue gas fraction to said first heat exchange means, thereby heating said volatile residue gas fraction and supplying said cooling of said gaseous first stream.

11. In an apparatus for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in said apparatus there being

(a) a cooling means to cool said gas stream under pressure;

(b) a dividing means connected to said cooling means to receive said cooled gas stream and to divide it into gaseous first and second streams;

(c) a first heat exchange means connected to said dividing means to receive said gaseous first stream and to cool it under pressure sufficiently to substantially condense it;

(d) a first expansion means connected to said first heat exchange means to receive said substantially condensed first stream and to expand it to a lower pressure, whereby said stream is further cooled;

(e) a second expansion means connected to said dividing means to receive said gaseous second stream and to expand it to said lower pressure; and

(f) a fractionation tower connected to said first expansion means and said second expansion means to receive said expanded streams therefrom;

the improvement wherein said apparatus includes

(1) a second heat exchange means connected to said first expansion means to receive said expanded cooled first stream, said second heat exchange means being further connected to said fractionation tower to receive a warmer distillation stream which rises from fractionation stages of a distillation column in said fractionation tower, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) a contacting and separating means connected to receive at least a portion of said at least partially condensed distillation stream and at least a portion of said expanded second stream wherein said streams are commingled in at least one contacting device, said contacting and separating means including separating means to separate the vapor and liquid after contact in said contacting device to form a vapor stream and a liquid stream, said contacting and separating means being further connected to supply said liquid stream to said distillation column in said fractionation tower as a liquid feed thereto;

(3) said contacting and separating means being further connected to supply said vapor stream to said first heat exchange means to heat said vapor stream and thereby supply the cooling of step (c), whereupon said heated vapor stream is thereafter discharged as said volatile residue gas fraction; and

(4) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means and said fractionation tower to maintain the overhead temperatures of said contacting and separating means and said fractionation tower at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

12. In an apparatus for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in said apparatus there being

(a) a dividing means to divide said gas stream into gaseous first and second streams;

(b) a first heat exchange means connected to said dividing means to receive said gaseous first stream and to cool it under pressure sufficiently to substantially condense it;

(c) a first expansion means connected to said first heat exchange means to receive said substantially condensed first stream and to expand it to a lower pressure, whereby said stream is further cooled;

(d) a cooling means connected to said dividing means to receive said gaseous second stream and to cool it under pressure sufficiently to partially condense it;

(e) a separation means connected to said cooling means to receive said cooled second stream and separate it thereby to provide a first vapor stream and a condensed stream;

(f) a second expansion means connected to said separation means to receive said first vapor stream and to expand it to said lower pressure;

(g) a third expansion means connected to said separation means to receive said condensed stream and to expand it to said lower pressure; and

(h) a fractionation tower connected to said first expansion means, said second expansion means, and said third expansion means to receive said expanded streams therefrom;

the improvement wherein said apparatus includes

(1) a second heat exchange means connected to said first expansion means to receive said expanded cooled first stream, said second heat exchange means being further connected to said fractionation tower to receive a warmer distillation stream which rises from fractionation stages of a distillation column in said fractionation tower, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) a contacting and separating means connected to receive at least a portion of said at least partially condensed distillation stream and at least a portion of said expanded first vapor stream wherein said streams are commingled in at least one contacting device, said contacting and separating means including separating means to separate the vapor and liquid after contact in said contacting device to form a second vapor stream and a liquid stream, said contacting and separating means being further connected to supply said liquid stream to said distillation column in said fractionation tower as a liquid feed thereto;

(3) said contacting and separating means being further connected to supply said second vapor stream to said first heat exchange means to heat said second vapor stream and thereby supply the cooling of step (b), whereupon said heated second vapor stream is thereafter discharged as said volatile residue gas fraction; and

(4) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means and said fractionation tower to maintain the overhead temperatures of said contacting and separating means and said fractionation tower at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

18. The improvement according to claims 12, 13, or 14 wherein the apparatus includes

(a) a second separation means connected to said second heat exchange means to receive said at least partially condensed distillation stream and separate it thereby to form a residual vapor stream and a liquid reflux stream, said second separation means being further connected to supply said liquid reflux stream to said contacting and separating means;

(b) a combining means connected to said second separation means to receive said residual vapor stream, said combining means being further connected to said contacting and separating means to receive said second vapor stream separated therefrom and combine it with said residual vapor stream to form said volatile residue gas fraction; and

(c) said combining means being further connected to supply said volatile residue gas fraction to said first heat exchange means, thereby heating said volatile residue gas fraction and supplying said cooling of said gaseous first stream.

13. In an apparatus for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in said apparatus there being

(a) a first cooling means to cool said gas stream under pressure;

(b) a dividing means connected to said first cooling means to receive said cooled gas stream and to divide it into gaseous first and second streams;

(c) a first heat exchange means connected to said dividing means to receive said gaseous first stream and to cool it under pressure sufficiently to substantially condense it;

(d) a first expansion means connected to said first heat exchange means to receive said substantially condensed first stream and to expand it to a lower pressure, whereby said stream is further cooled;

(e) a second cooling means connected to said dividing means to receive said gaseous second stream and to cool it under pressure sufficiently to partially condense it;

(f) a separation means connected to said second cooling means to receive said cooled second stream and separate it thereby to provide a first vapor stream and a condensed stream;

(g) a second expansion means connected to said separation means to receive said first vapor stream and to expand it to said lower pressure;

(h) a third expansion means connected to said separation means to receive said condensed stream and to expand it to said lower pressure; and

(i) a fractionation tower connected to said first expansion means, said second expansion means, and said third expansion means to receive said expanded streams therefrom;

the improvement wherein said apparatus includes

(1) a second heat exchange means connected to said first expansion means to receive said expanded cooled first stream, said second heat exchange means being further connected to said fractionation tower to receive a warmer distillation stream which rises from fractionation stages of a distillation column in said fractionation tower, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) a contacting and separating means connected to receive at least a portion of said at least partially condensed distillation stream and at least a portion of said expanded first vapor stream wherein said streams are commingled in at least one contacting device, said contacting and separating means including separating means to separate the vapor and liquid after contact in said contacting device to form a second vapor stream and a liquid stream, said contacting and separating means being further connected to supply said liquid stream to said distillation column in said fractionation tower as a liquid feed thereto;

(3) said contacting and separating means being further connected to supply said second vapor stream to said first heat exchange means to heat said second vapor stream and thereby supply the cooling of step (c), whereupon said heated second vapor stream is thereafter discharged as said volatile residue gas fraction; and

(4) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means and said fractionation tower to maintain the overhead temperatures of said contacting and separating means and said fractionation tower at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

14. In an apparatus for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in said apparatus there being

(a) a cooling means to cool said gas stream under pressure sufficiently to partially condense it;

(b) a separation means connected to said cooling means to receive said cooled gas stream and separate it thereby to provide a first vapor stream and a condensed stream;

(c) a dividing means connected to said separation means to receive said first vapor stream and to divide it into gaseous first and second streams;

(d) a first heat exchange means connected to said dividing means to receive said gaseous first stream and to cool it under pressure sufficiently to substantially condense it;

(e) a first expansion means connected to said first heat exchange means to receive said substantially condensed first stream and to expand it to a lower pressure, whereby said stream is further cooled;

(f) a second expansion means connected to said dividing means to receive said gaseous second stream and to expand it to said lower pressure;

(g) a third expansion means connected to said separation means to receive said condensed stream and to expand it to said lower pressure; and

(h) a fractionation tower connected to said first expansion means, said second expansion means, and said third expansion means to receive said expanded streams therefrom;

the improvement wherein said apparatus includes

(1) a second heat exchange means connected to said first expansion means to receive said expanded cooled first stream, said second heat exchange means being further connected to said fractionation tower to receive a warmer distillation stream which rises from fractionation stages of a distillation column in said fractionation tower, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) a contacting and separating means connected to receive at least a portion of said at least partially condensed distillation stream and at least a portion of said expanded second stream wherein said streams are commingled in at least one contacting device, said contacting and separating means including separating means to separate the vapor and liquid after contact in said contacting device to form a second vapor stream and a liquid stream, said contacting and separating means being further connected to supply said liquid stream to said distillation column in said fractionation tower as a liquid feed thereto;

(3) said contacting and separating means being further connected to supply said second vapor stream to said first heat exchange means to heat said second vapor stream and thereby supply the cooling of step (d), whereupon said heated second vapor stream is thereafter discharged as said volatile residue gas fraction; and

(4) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means and said fractionation tower to maintain the overhead temperatures of said contacting and separating means and said fractionation tower at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

15. In an apparatus for the separation of a gas stream containing methane, C₂ components, C₃ components and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing said C₂ components, C₃ components and heavier hydrocarbon components or said C₃ components and heavier hydrocarbon components, in said apparatus there being

(a) a cooling means to cool said gas stream under pressure sufficiently to partially condense it;

(b) a separation means connected to said cooling means to receive said cooled gas stream and separate it thereby to provide a first vapor stream and a condensed stream;

(c) a dividing means connected to said separation means to receive said first vapor stream and to divide it into gaseous first and second streams;

(d) a combining means connected to combine said gaseous first stream and at least a portion of said condensed stream into a combined stream;

(e) a first heat exchange means connected to said combining means to receive said combined stream and to cool it under pressure sufficiently to substantially condense it;

(f) a first expansion means connected to said first heat exchange means to receive said substantially condensed combined stream and to expand it to a lower pressure, whereby said stream is further cooled;

(g) a second expansion means connected to said dividing means to receive said gaseous second stream and to expand it to said lower pressure;

(h) a third expansion means connected to said separation means to receive any remaining portion of said condensed stream and to expand it to said lower pressure; and

(i) a fractionation tower connected to said first expansion means, said second expansion means, and said third expansion means to receive said expanded streams therefrom;

the improvement wherein said apparatus includes

(1) a second heat exchange means connected to said first expansion means to receive said expanded cooled combined stream, said second heat exchange means being further connected to said fractionation tower to receive a warmer distillation stream which rises from fractionation stages of a distillation column in said fractionation tower, thereby cooling said distillation stream sufficiently to at least partially condense it;

(2) a contacting and separating means connected to receive at least a portion of said at least partially condensed distillation stream and at least a portion of said expanded second stream wherein said streams are commingled in at least one contacting device, said contacting and separating means including separating means to separate the vapor and liquid after contact in said contacting device to form a second vapor stream and a liquid stream, said contacting and separating means being further connected to supply said liquid stream to said distillation column in said fractionation tower as a liquid feed thereto;

(3) said contacting and separating means being further connected to supply said second vapor stream to said first heat exchange means to heat said second vapor stream and thereby supply the cooling of step (e), whereupon said heated second vapor stream is thereafter discharged as said volatile residue gas fraction; and

(4) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means and said fractionation tower to maintain the overhead temperatures of said contacting and separating means and said fractionation tower at temperatures whereby the major portions of the components in said relatively less volatile fraction are recovered.

19. The improvement according to claim 15 wherein the apparatus includes

(a) a second separation means connected to said second heat exchange means to receive said at least partially condensed distillation stream and separate it thereby to form a residual vapor stream and a liquid reflux stream, said second separation means being further connected to supply said liquid reflux stream to said contacting and separating means;

(b) a combining means connected to said second separation means to receive said residual vapor stream, said combining means being further connected to said contacting and separating means to receive said second vapor stream separated therefrom and combine it with said residual vapor stream to form said volatile residue gas fraction; and

(c) said combining means being further connected to supply said volatile residue gas fraction to said first heat exchange means, thereby heating said volatile residue gas fraction and supplying said cooling of said combined stream.