Hydrocarbon gas processing including a single equipment item processing assembly

• US 9,939,196 B2
• Filed: 06/02/2010
• Issued: 04/10/2018
• Est. Priority Date: 02/17/2009
• Status: Active Grant

• Current Assignee: UOP Llc (Honeywell International Inc.), SME Products LP
• Original Assignee: Ortloff Enigneers, Ltd., SME Products LP
• Inventors: Johnke, Andrew F., Lewis, W. Larry, Wilkinson, John D., Lynch, Joe T., Hudson, Hank M., Cuellar, Kyle T.
• Primary Examiner(s): Pettitt, John F
• Application Number:
  US12/792,136
• Publication Number:
  US 20100326134A1
• Time in Patent Office: 2,869 Days
• Field of Search: 62617, 62618, 62619, 62620, 62627
• CPC Class Codes: F25J 2200/02 in a single pressure main column system
• CPC Class Codes: F25J 2200/50 using multiple (re-)boiler-condensers at different heights of the column
• CPC Class Codes: F25J 2200/74 Refluxing the column with at least a part of the partially condensed overhead gas
• CPC Class Codes: F25J 2200/80 using integrated mass and heat exchange, i.e. non-adiabatic rectification in a reflux exchanger or dephlegmator
• CPC Class Codes: F25J 2205/04 in the feed line, i.e. upstream of the fractionation step
• CPC Class Codes: F25J 2215/04 Recovery of liquid products
• CPC Class Codes: F25J 2235/80 the fluid being carbon dioxide
• 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 2240/40 Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval
• CPC Class Codes: F25J 2260/20 Integration in an installation for liquefying or solidifying a fluid stream
• CPC Class Codes: F25J 2260/80 Integration in an installation using carbon dioxide, e.g. for EOR, sequestration, refrigeration etc.
• CPC Class Codes: F25J 2270/02 Internal refrigeration with liquid vaporising loop
• CPC Class Codes: F25J 2270/90 External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
• 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 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 3/0266 separation of carbon dioxide production of carbon dioxide in general C01B32/00
• CPC Class Codes: F25J 3/0295 Start-up or control of the process; Details of the apparatus used, e.g. sieve plates, packings
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A process and an apparatus are disclosed for a compact processing assembly to remove carbon dioxide from a hydrocarbon gas stream. The gas stream is cooled, expanded to intermediate pressure, and fed to the top of a mass transfer means. A distillation liquid stream from the mass transfer means is heated in a first heat and mass transfer means to strip out its volatile components and form a bottom liquid product. A distillation vapor stream from the mass transfer means is combined with any vapor in the expanded cooled gas stream, and the combined vapor stream is cooled in a second heat and mass transfer means to partially condense it, forming a condensed stream that is fed to the top of the mass transfer means. A portion of the bottom liquid product is subcooled, expanded to lower pressure, and used to cool the combined vapor stream.

Claims

1. A process for the separation of a gas stream containing at least methane and carbon dioxide 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 carbon dioxide wherein

(1) said gas stream is cooled in a first means for providing heat and mass transfer that is housed in a single equipment item processing assembly thereby forming a cooled stream, and further cooled in a lower region of one or more means for providing heat exchange housed in said processing assembly, thereby forming a further cooled stream;

(2) said further cooled stream is expanded to intermediate pressure whereby it is further cooled;

(3) said expanded further cooled stream is supplied as a top feed to a mass transfer means housed in said processing assembly, said mass transfer means having a lower region and an upper region;

(4) a distillation liquid stream is collected from the lower region of said mass transfer means and heated in said first means for providing heat and mass transfer, said first means for providing heat and mass transfer being configured to provide heat exchange between

(a) said gas stream flowing through one pass of said first means for providing heat and mass transfer; and

(b) said distillation liquid stream flowing downward from said mass transfer means,

so that said gas stream is cooled to form said cooled stream while heating said distillation liquid stream before it leaves said first means for providing heat and mass transfer; and

wherein as said distillation liquid stream is heated, a portion of it is vaporized to form stripping vapors that rise upward as remaining liquid continues flowing downward through said first means for providing heat and mass transfer; and

wherein said first means for providing heat and mass transfer provides continuous contact between said stripping vapors and said remaining liquid so that said first means for providing heat and mass transfer also functions to provide mass transfer between vapor and liquid phases, stripping said remaining liquid of methane and lighter components; and

wherein said first means for providing heat and mass transfer supplies at least a portion of the cooling of step (1) while simultaneously stripping the more volatile components from said remaining liquid stream, and thereafter discharging said heated and stripped remaining liquid from said processing assembly as said relatively less volatile fraction;

wherein said first means for providing heat and mass transfer does not include external reboilers;

(5) a first distillation vapor stream is collected from the upper region of said mass transfer means and combined with a vapor portion of said expanded further cooled stream to form a second distillation vapor stream;

(6) said second distillation vapor stream is cooled in a second means for providing heat and mass transfer that is housed in said processing assembly, thereby condensing the less volatile components from said second distillation vapor stream and forming a condensed stream and a third distillation vapor stream;

wherein said second means for providing heat and mass transfer does not include external reflux equipment items;

(7) at least a portion of said condensed stream is supplied as another top feed to said mass transfer means;

(8) said relatively less volatile fraction is divided into at least first and second streams;

(9) said second stream is cooled in an upper region of said one or more heat exchange means and thereafter expanded to lower pressure whereby it is further cooled;

(10) said expanded cooled second stream is heated, in said second means for providing heat and mass transfer, said second means for providing heat and mass transfer being configured to provide heat exchange between

(a) said second distillation vapor stream flowing upward through one pass of said second means for providing heat and mass transfer; and

(b) said expanded cooled second stream flowing downward,

so that said second distillation vapor stream is cooled while heating said expanded cooled second stream;

wherein as said second distillation vapor stream is cooled, a portion of said second distillation vapor stream is condensed and said condensed stream is thereby formed and falls downward while said third distillation vapor stream is also formed and flows upward through said second means for providing heat and mass transfer;

wherein said second means for providing heat and mass transfer provides continuous contact between said condensed stream and said third distillation vapor stream so that said second means for providing heat and mass transfer also functions to provide mass transfer between vapor and liquid phases, thereby providing rectification of said third distillation vapor stream; and

wherein said second means for providing heat and mass transfer supplies at least a portion of the cooling of step (6);

(11) said third distillation vapor stream is heated in said lower region of said one or more means for providing heat exchange that is housed in said processing assembly, said one or more means for providing heat exchange being configured to provide heat exchange between

(a) said cooled stream flowing through one pass in said lower region of said one or more heat exchange means,

(b) said heated expanded cooled second stream flowing through another pass in said lower region of said one or more heat exchange means, and

(c) said third distillation vapor stream arising from said second means for providing heat and mass transfer,

so that said third distillation vapor stream is heated to form a partially heated third distillation vapor stream and said heated expanded cooled second stream is further heated while said cooled stream is further cooled; and

wherein said one or more means for providing heat exchange is further configured to provide heat exchange between

(d) said second stream flowing through one pass in said upper region of said one or more heat exchange means, and

(e) said partially heated third distillation vapor stream that has been heated in said lower region of said one or more means for providing heat exchange,

wherein said second stream is cooled while further heating said partially heated third distillation vapor stream to form a heated third distillation vapor stream and wherein said one or more means for providing heat exchange supplies at least a portion of the cooling of steps (1) and (9), and thereafter discharging said heated third distillation vapor stream from said processing assembly as said volatile residue gas fraction;

wherein said one or more heat exchange means does not include external reflux equipment items; and

(12) the quantities and temperatures of said feed streams to said mass transfer means are effective to maintain the temperature of said upper region of said mass transfer means at a temperature whereby the major portion of said carbon dioxide is recovered in said relatively less volatile fraction.

2. The process according to claim 1 wherein

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

(2) 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;

(3) said at least one liquid stream is expanded to intermediate pressure;

(4) said expanded liquid stream is supplied as said top feed to said mass transfer means;

(5) said vapor stream is expanded to said intermediate pressure and is supplied as a feed to said processing assembly below said second means for providing heat and mass transfer; and

(6) said first distillation vapor stream is collected from the upper region of said mass transfer means and combined with the vapor portion of said expanded vapor stream to form said second distillation vapor stream.

3. The process according to claim 2 wherein said separating means is housed in said processing assembly.

4. The process according to claim 2 or 3 wherein

(1) an additional mass transfer means is housed in said processing assembly below said second means for providing heat and mass transfer, said additional mass transfer means having a lower region and an upper region;

(2) said expanded vapor stream is supplied as a top feed to said additional mass transfer means;

(3) said first distillation vapor stream is directed to said additional mass transfer means as a bottom feed thereto;

(4) a fourth distillation vapor stream is collected from the upper region of said additional mass transfer means and combined with said vapor portion of said expanded vapor stream to form said second distillation vapor stream;

(5) at least a portion of said condensed stream is supplied as another top feed to said additional mass transfer means; and

(6) the quantities and temperatures of said feed streams to said additional mass transfer means are effective to maintain the temperature of said upper region of said additional mass transfer means at a temperature whereby the major portion of said carbon dioxide is recovered in said relatively less volatile fraction.

5. The process according to claim 1 wherein said first means for providing heat and mass transfer includes one or more passes for an external heating medium to supplement the heating supplied by said gas stream for said stripping of said more volatile components from said remaining liquid stream.

6. The process according to claim 4 wherein said first means for providing heat and mass transfer includes one or more passes for an external heating medium to supplement the heating supplied by said gas stream for said stripping of said more volatile components from said distillation liquid stream.

7. An apparatus for the separation of a gas stream containing at least methane and carbon dioxide 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 carbon dioxide comprising

(1) first means for providing heat and mass transfer housed in a single equipment item processing assembly to cool said gas stream;

(2) one or more means for providing heat exchange housed in said processing assembly and connected to said first means for providing heat and mass transfer to receive said cooled gas stream and further cool it, thereby forming a cooled stream;

(3) first expansion means connected to said one or more means for providing heat exchange to receive said cooled stream and expand it to intermediate pressure;

(4) mass transfer means housed in said processing assembly and connected to said first expansion means to receive said expanded cooled stream as a top feed thereto, said mass transfer means having a lower region and an upper region;

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

(6) said first means for providing heat and mass transfer being further connected to said liquid collecting means to receive said distillation liquid stream and heat it, said first means for providing heat and mass transfer being configured to provide heat exchange between

(a) said gas stream flowing through one pass of said first means for providing heat and mass transfer; and

(b) said distillation liquid stream flowing downward from said mass transfer means,

so that said gas stream is cooled to form said cooled stream while heating said distillation liquid stream before it leaves said first means for providing heat and mass transfer; and

wherein as said distillation liquid stream is heated, a portion of it is vaporized to form stripping vapors that rise upward as remaining liquid continues flowing downward through said first means for providing heat and mass transfer; and

wherein said first means for providing heat and mass transfer provides continuous contact between said stripping vapors and said remaining liquid so that said first means for providing heat and mass transfer also functions to provide mass transfer between vapor and liquid phases, stripping said remaining liquid of methane and lighter components; and

wherein said first means for providing heat and mass transfer supplies at least a portion of the cooling of step (1) while simultaneously stripping the more volatile components from said remaining liquid stream, and thereafter discharging said heated and stripping remaining liquid from said processing assembly as said relatively less volatile fraction;

wherein said first means for providing heat and mass transfer does not include external reboilers;

(7) vapor collecting means housed in said processing assembly and connected to said mass transfer means to receive a first distillation vapor stream from the upper region of said mass transfer means;

(8) combining means connected to said vapor collecting means to receive said first distillation vapor stream and combine it with any vapor portion of said expanded cooled stream and form thereby a second distillation vapor stream;

(9) second means for providing heat and mass transfer housed in said processing assembly and connected to said combining means to receive said second distillation vapor stream and cool it, thereby forming a condensed stream and a third distillation vapor stream;

(10) said mass transfer means being further connected to said second means for providing heat and mass transfer to receive at least a portion of said condensed stream as another top feed thereto;

(11) dividing means connected to said processing assembly to receive said relatively less volatile fraction and divide it into at least first and second streams;

(12) said one or more means for providing heat exchange being connected to said dividing means to receive said second stream and cool it;

(13) second expansion means connected to said one or more means for providing heat exchange means to receive said cooled second stream and expand it to lower pressure;

(14) said second means for providing heat and mass transfer being further connected to said second expansion means to receive said expanded cooled second stream and heat it, thereby to supply at least a portion of the cooling of step (9);

said second means for providing heat and mass transfer being configured to provide heat exchange between

(a) said second distillation vapor stream flowing upward through one pass of said second means for providing heat and mass transfer; and

(b) said expanded cooled second stream flowing downward,

so that said second distillation vapor stream is cooled while heating said expanded cooled second stream;

wherein as said second distillation vapor stream is cooled, a portion of said second distillation vapor steam is condensed and said condensed stream is thereby formed and falls downward while said third distillation vapor stream is also formed and flows upward through said second means for providing heat and mass transfer;

wherein said second means for providing heat and mass transfer provides continuous contact between said condensed stream and said third distillation vapor stream so that said second means for providing heat and mass transfer also functions to provide mass transfer between vapor and liquid phases, thereby providing rectification of said third distillation vapor stream;

(15) said third distillation vapor stream is heated in a lower region of said one or more means for providing heat exchange that is housed in said processing assembly, said one or more means for providing heat exchange being configured to provide heat exchange between

(a) said cooled stream flowing through one pass in said lower region of said one or more heat exchange means,

(b) said heated expanded cooled second stream flowing through another pass in said lower region of said one or more heat exchange means, and

(c) said third distillation vapor stream arising from said second means for providing heat and mass transfer,

so that said third distillation vapor stream is heated to form a partially heated third distillation vapor stream and said heated expanded cooled second stream is further heated while said cooled stream is further cooled; and

wherein said one or more means for providing heat exchange is further configured to provide heat exchange between

(d) said second stream flowing through one pass in an upper region of said one or more heat exchange means, and

(e) said partially heated third distillation vapor stream that has been heated in said lower region of said one or more means for providing heat exchange,

wherein said second stream is cooled while further heating said partially heated third distillation vapor stream to form a heated third distillation vapor stream and wherein said one or more means for providing heat exchange supplies at least a portion of the cooling of steps (1) and (12), and thereafter discharging said heated third distillation vapor stream from said processing assembly as said volatile residue gas fraction;

wherein said one or more heat exchange means does not include external reflux equipment items; and

(16) control means adapted to regulate the quantities and temperatures of said feed streams to said upper region of said mass transfer means to maintain the temperature of said upper region of said mass transfer means at a temperature whereby the major portion of said carbon dioxide is recovered in said relatively less volatile fraction.

8. The apparatus according to claim 7 wherein

(1) said one or more means for providing heat exchange is adapted to receive said cooled gas stream and further cool it, thereby forming a partially condensed gas stream;

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

(3) said first expansion means is connected to said separating means to receive said at least one liquid stream and expand it to intermediate pressure;

(4) said mass transfer means is connected to said first expansion means to receive said expanded liquid stream as said top feed thereto;

(5) a third expansion means is connected to said separating means to receive said vapor stream and expand it to said intermediate pressure, said third expansion means being further connected to said processing assembly to supply said expanded vapor stream as a feed thereto below said second means for providing heat and mass transfer; and

(6) said combining means is connected to said vapor collecting means to receive said first distillation vapor stream and combine it with the vapor portion of said expanded vapor stream and form thereby said second distillation vapor stream.

9. The apparatus according to claim 8 wherein said separating means is housed in said processing assembly.

10. The apparatus according to claim 8 or 9 wherein

(1) an additional mass transfer means is housed in said processing assembly below said second means for providing heat and mass transfer, said additional mass transfer means having a lower region and an upper region;

(2) said additional mass transfer means is connected to said third expansion means to receive said expanded vapor stream as a top feed thereto;

(3) said additional mass transfer means is further connected to said vapor collecting means to receive said first distillation vapor stream as a bottom feed thereto;

(4) an additional vapor collecting means is housed in said processing assembly and connected to said additional mass transfer means to receive a fourth distillation vapor stream from the upper region of said additional mass transfer means;

(5) said combining means is adapted to be connected to said additional vapor collecting means to receive said fourth distillation vapor stream and combine it with said vapor portion of said expanded vapor stream, thereby forming said second distillation vapor stream;

(6) said additional mass transfer means is further connected to said second means for providing heat and mass transfer to receive at least a portion of said condensed stream as another top feed thereto; and

(7) said control means is adapted to regulate the quantities and temperatures of said feed streams to said upper region of said additional mass transfer means to maintain the temperature of said upper region of said additional mass transfer means at a temperature whereby the major portion of said carbon dioxide is recovered in said relatively less volatile fraction.

11. The apparatus according to claim 7, 8, or 9 wherein said first means for providing heat and mass transfer includes one or more passes for an external heating medium to supplement the heating supplied by said gas stream for said stripping of said more volatile components from said distillation liquid stream.

12. The apparatus according to claim 10 wherein said first means for providing heat and mass transfer includes one or more passes for an external heating medium to supplement the heating supplied by said gas stream for said stripping of said more volatile components from said distillation liquid stream.