Hydrocarbon Gas Processing

• US 20150315106A2
• Filed: 08/18/2014
• Published: 11/05/2015
• Est. Priority Date: 09/11/2013
• Status: Active Grant

• Current Assignee: UOP Llc (Honeywell International Inc.), SME Products LP
• Original Assignee: Ortloff Enigneers, Ltd., SME Products LP
• Inventors: Miller, Scott A., Wilkinson, John D., Lynch, Joe T., Hudson, Hank M., Cuellar, Kyle T., Johnke, Andrew F., Lewis, W. Larry
• Granted Patent: US 9,783,470 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 3/26 Fractionating columns in which vapour and liquid flow past each other, or in which the fluid is sprayed into the vapour, or in which a two-phase mixture is passed in one direction
• CPC Class Codes: B01D 3/32 Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
• CPC Class Codes: B01D 3/322 Reboiler specifications
• CPC Class Codes: B01D 5/0063 Reflux condensation
• CPC Class Codes: C07C 7/09 by fractional condensation
• CPC Class Codes: C10G 5/06 by cooling or compressing
• CPC Class Codes: C10L 2290/06 Heat exchange, direct or indirect
• CPC Class Codes: C10L 2290/48 Expanders, e.g. throttles or flash tanks
• CPC Class Codes: C10L 2290/541 Absorption of impurities during preparation or upgrading of a fuel
• CPC Class Codes: C10L 2290/543 Distillation, fractionation or rectification for separating fractions, components or impurities during preparation or upgrading of a fuel
• CPC Class Codes: C10L 2290/545 Washing, scrubbing, stripping, scavenging for separating fractions, components or impurities during preparation or upgrading of a fuel
• 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 1/0022 Hydrocarbons, e.g. natural gas
• CPC Class Codes: Y02P 30/00 Technologies relating to oil refining and petrochemical industry

Abstract

A process and an apparatus are disclosed for a compact processing assembly to remove C₅ and heavier hydrocarbon components from a hydrocarbon gas stream. The hydrocarbon gas stream is expanded to lower pressure and supplied to the processing assembly between an absorbing means and a mass transfer means. A distillation vapor stream is collected from the upper region of the absorbing means and cooled in a first heat and mass transfer means inside the processing assembly to partially condense it, forming a residual vapor stream and a condensed stream. The condensed stream is supplied to the absorbing means at its top feed point. A distillation liquid stream is collected from the lower region of the mass transfer means and directed into a second heat and mass transfer means inside the processing assembly to heat it and strip out its volatile components.

Claims

1. A process for the separation of a gas stream containing methane, C₂ components, C₃ components, C₄ components, C₅ components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C₅ components and heavier hydrocarbon components wherein

(1) said gas stream is expanded to lower pressure;

(2) said expanded gas stream is supplied as a feed between an absorbing means and a mass transfer means housed in a processing assembly, said absorbing means being located above said mass transfer means;

(3) a first distillation vapor stream is collected from an upper region of said absorbing means and cooled in a first heat and mass transfer means housed in said processing assembly to simultaneously condense the less volatile components from said first distillation vapor stream, thereby forming a condensed stream and a second distillation vapor stream, whereupon said second distillation vapor stream is discharged from said processing assembly as said volatile residue gas fraction;

(4) said condensed stream is supplied as a top feed to said absorbing means;

(5) a distillation liquid stream is collected from a lower region of said mass transfer means and heated in a second heat and mass transfer means housed in said processing assembly to simultaneously strip the more volatile components from said distillation liquid stream, whereupon said heated and stripped distillation liquid stream is discharged from said processing assembly as said relatively less volatile fraction; and

(6) a control means is adapted to maintain the temperature of said second distillation vapor stream at a temperature whereby the major portion of said C₅ components and heavier hydrocarbon components are recovered in said relatively less volatile fraction.

2. The process according to claim 1 wherein

(a) said gas stream is cooled;

and

(b) said cooled gas stream is expanded to said lower pressure and supplied as said feed between said absorbing means and said mass transfer means.

3. The process according to claim 1 wherein

(a) said gas stream is cooled sufficiently to partially condense it;

(b) said partially condensed gas stream is supplied to a separating means and is separated therein to provide a vapor stream and at least one liquid stream;

(c) said vapor stream is expanded to said lower pressure and supplied as said feed between said absorbing means and said mass transfer means; and

(d) at least a portion of said at least one liquid stream is expanded to said lower pressure and heated, and thereafter is supplied as an additional feed to said processing assembly below said mass transfer means.

4. The process according to claim 2 wherein said second distillation vapor stream is heated in one or more heat exchange means housed in said processing assembly, thereby to supply at least a portion of the cooling of step (a), and thereafter discharging said heated second distillation vapor stream from said processing assembly as said volatile residue gas fraction.

5. The process according to claim 3 wherein said second distillation vapor stream is heated in one or more heat exchange means housed in said processing assembly, thereby to supply at least a portion of the cooling of step (a), and thereafter discharging said heated second distillation vapor stream from said processing assembly as said volatile residue gas fraction.

6. The process according to claim 3 or 5 wherein said separating means is housed in said processing assembly.

7. The process according to claim 2 or 4 wherein

(a) a collecting means is housed in said processing assembly;

(b) an additional heat and mass transfer means is included inside said collecting means, said additional heat and mass transfer means including one or more passes for an external refrigeration medium;

(c) said cooled gas stream is supplied to said collecting means and directed to said additional heat and mass transfer means to be further cooled by said external refrigeration medium; and

(d) said further cooled gas stream is expanded to said lower pressure and supplied as said feed between said absorbing means and said mass transfer means.

8. The process according to claim 3 or 5 wherein

(a) an additional heat and mass transfer means is included inside said separating means, said additional heat and mass transfer means including one or more passes for an external refrigeration medium;

(b) said vapor stream is directed to said additional heat and mass transfer means to be cooled by said external refrigeration medium to form additional condensate; and

(c) said additional condensate becomes a part of said at least one liquid stream separated therein.

9. The process according to claim 6 wherein

(a) an additional heat and mass transfer means is included inside said separating means, said additional heat and mass transfer means including one or more passes for an external refrigeration medium;

(b) said vapor stream is directed to said additional heat and mass transfer means to be cooled by said external refrigeration medium to form additional condensate; and

(c) said additional condensate becomes a part of said at least one liquid stream separated therein.

10. An apparatus for the separation of a gas stream containing methane, C₂ components, C₃ components, C₄ components, C₅ components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C₅ components and heavier hydrocarbon components comprising

(1) expansion means connected to receive said gas stream under pressure and expand it to a lower pressure;

(2) a processing assembly connected to said expansion means to receive said expanded gas stream as a feed between an absorbing means and a mass transfer means housed in said processing assembly, said absorbing means being located above said mass transfer means;

(3) vapor collecting means housed in said processing assembly and connected to said absorbing means to receive a first distillation vapor stream from an upper region of said absorbing means;

(4) first heat and mass transfer means housed in said processing assembly and connected to said vapor collecting means to receive said first distillation vapor stream and cool it while simultaneously condensing the less volatile components from said first distillation vapor stream, thereby forming a condensed stream and a second distillation vapor stream, whereupon said second distillation vapor stream is discharged from said processing assembly as said volatile residue gas fraction;

(5) said absorbing means being further connected to said first heat and mass transfer means to receive said condensed stream as a top feed thereto;

(6) liquid collecting means housed in said processing assembly and connected to said mass transfer means to receive a distillation liquid stream from a lower region of said mass transfer means;

(7) second heat and mass transfer means housed in said processing assembly and connected to said liquid collecting means to receive said distillation liquid stream and heat it, thereby simultaneously stripping the more volatile components from said distillation liquid stream, whereupon said heated and stripped distillation liquid stream is discharged from said processing assembly as said relatively less volatile fraction; and

(8) control means adapted to maintain the temperature of said second distillation vapor stream at a temperature whereby the major portion of said C₅ components and heavier hydrocarbon components are recovered in said relatively less volatile fraction.

11. The apparatus according to claim 10 wherein

(a) one or more heat exchange means is connected to receive said gas stream under pressure and cool it;

and

(b) said expansion means is adapted to be connected to said one or more heat exchange means to receive said cooled gas stream and expand it to said lower pressure, whereupon said expanded cooled gas stream is supplied to said processing assembly as said feed between said absorbing means and said mass transfer means.

12. The apparatus according to claim 10 wherein

(a) one or more heat exchange means is connected to receive said gas stream under pressure and cool it sufficiently to partially condense it;

(b) a separating means is connected to said one or more heat exchange means to receive said partially condensed gas stream and separate it into a vapor stream and at least one liquid stream;

(c) said expansion means is adapted to be connected to said separating means to receive said vapor stream and expand it to said lower pressure, whereupon said expanded vapor stream is supplied to said processing assembly as said feed between said absorbing means and said mass transfer means;

(d) an additional expansion means is connected to said separating means to receive at least a portion of said at least one liquid stream and expand it to said lower pressure, thereby forming an expanded liquid stream; and

(e) a heating means is connected to said additional expansion means to receive said expanded liquid stream and heat it, said heating means being further connected to said processing assembly to supply said heated expanded liquid stream as an additional feed to said processing assembly below said mass transfer means.

13. The apparatus according to claim 11 wherein

(i) said one or more heat exchange means is housed in said processing assembly;

and

(ii) said one or more heat exchange means is further connected to said first heat and mass transfer means to receive said second distillation vapor stream and heat it, thereby to supply at least a portion of the cooling of element (a), and thereafter discharging said heated second distillation vapor stream from said processing assembly as said volatile residue gas fraction.

14. The apparatus according to claim 12 wherein

(i) said one or more heat exchange means is housed in said processing assembly;

and

(ii) said one or more heat exchange means is further connected to said first heat and mass transfer means to receive said second distillation vapor stream and heat it, thereby to supply at least a portion of the cooling of element (a), and thereafter discharging said heated second distillation vapor stream from said processing assembly as said volatile residue gas fraction.

15. The apparatus according to claim 12 or 14 wherein said separating means is housed in said processing assembly.

16. The apparatus according to claim 11 or 13 wherein

(a) a collecting means is housed in said processing assembly;

(b) an additional heat and mass transfer means is included inside said collecting means, said additional heat and mass transfer means including one or more passes for an external refrigeration medium;

(c) said collecting means is connected to said one or more heat exchange means to receive said cooled gas stream and direct it to said additional heat and mass transfer means to be further cooled by said external refrigeration medium; and

(d) said expansion means is adapted to be connected to said collecting means to receive said further cooled gas stream and expand it to said lower pressure, whereupon said expanded further cooled gas stream is supplied to said processing assembly as said feed between said absorbing means and said mass transfer means.

17. The apparatus according to claim 12 or 14 wherein

(a) an additional heat and mass transfer means is included inside said separating means, said additional heat and mass transfer means including one or more passes for an external refrigeration medium;

(b) said vapor stream is directed to said additional heat and mass transfer means to be cooled by said external refrigeration medium to form additional condensate; and

(c) said additional condensate becomes a part of said at least one liquid stream separated therein.

18. The apparatus according to claim 15 wherein

(a) an additional heat and mass transfer means is included inside said separating means, said additional heat and mass transfer means including one or more passes for an external refrigeration medium;

(b) said vapor stream is directed to said additional heat and mass transfer means to be cooled by said external refrigeration medium to form additional condensate; and

(c) said additional condensate becomes a part of said at least one liquid stream separated therein.