Patent · US9396854B2 · B2 · US

Process and apparatus for removing gaseous contaminants from gas stream comprising gaseous contaminants

(11) Publication number

US9396854B2

(21) Application number

13/061,435

(22) Filing date

2009-08-27

(30) Priority date

2008-08-29

(43) Publication date

2016-07-19

(45) Date of grant

2016-07-19

(51) IPC

B01D 9/04; F25J 3/08; H01R 24/58; C10L 3/10; F25J 3/06; H01F 27/28; H01F 5/04

(52) CPC

H01F Magnets; inductances; transformers; selection of materials for their magnetic properties: 5/04, 27/2895
B01D Separation: 2256/24, 53/002
C10L Fuels not otherwise provided for; natural gas; synthetic natural gas obtained by processes not covered by subclasses C10G or C10K; liquified petroleum gas; use of additives to fuels or fires; fire-lighters: 3/10, 3/102, 3/104
F25J Liquefaction, solidification or separation of gases or gaseous {or liquefied gaseous} mixtures by pressure and cold treatment {or by bringing them into the supercritical state}: 2205/02, 2205/20, 2210/60, 2215/04, 2215/60, 2215/80, 2220/64, 2220/66, 2240/02, 2240/40, 2240/60, 2245/02, 2270/12, 2270/60, 2270/66, 2290/42, 3/061, 3/0635, 3/067
H01R Electrically-conductive connections; structural associations of a plurality of mutually-insulated electrical connecting elements; coupling devices; current collectors: 13/6633, 13/6658, 24/64

(73) Assignee

Shell Oil Co

(72) Inventors

Henricus Abraham GEERS; Helmar Van Santen

(54) Title

Process and apparatus for removing gaseous contaminants from gas stream comprising gaseous contaminants

(57) Abstract

The invention provides a process and a device for removing gaseous contaminants from a feed gas stream which comprises methane and gaseous contaminants, in which process the feed gas stream is cooled to obtain a slurry which comprises solid contaminant, liquid phase contaminant and a methane enriched gaseous phase, the slurry so obtained is introduced into a cryogenic separation device (4) in which from the top the methane enriched gaseous phase is removed (5), the slurry is diluted with liquid phase contaminant (6) and introduced as suction fluid into an ejector (9) via which it is passed into a heat exchanger (10) arranged outside the separation device and wherein solid contaminant is melted into liquid phase contaminant, part of the liquid phase contaminant so obtained is recycled (6) to dilute the slurry of contaminants inside the separation device and part (13) is introduced into the bottom part of the separation device, liquid phase is withdrawn (14) from the bottom part of the separation device, and part of the withdrawn liquid phase contaminant is recovered as a stream product (16) and part is recycled (17) to the ejector for use a motive fluid.

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Claims (14)

A process for removing gaseous contaminants from a feed gas stream which comprises methane and gaseous contaminants, the process comprising: 1) providing the feed gas stream; 2) cooling the feed gas stream to a temperature at which part of the contaminants solidify to obtain a slurry which comprises solid contaminant, liquid phase contaminant and a methane enriched gaseous phase in a conduit; 3) introducing the slurry obtained in step 2) from the conduit into the top or intermediate part of a cryogenic separation device; 4) removing from the top part of the cryogenic separation device a stream which comprises the methane enriched gaseous phase such that a slurry containing liquid and solid phases remains in the cryogenic separation device; 5) introducing a stream comprising the liquid phase contaminant obtained in step 6) below into the intermediate or the bottom part or both of the cryogenic separation device to obtain a diluted slurry of contaminants; 6) introducing the diluted slurry of contaminants obtained in step 5) via an eductor into a heat exchanger in which solid contaminant present in the diluted slurry of contaminants is melted into liquid phase contaminant, wherein the heat exchanger is positioned outside the separation device, and the eductor is arranged inside the cryogenic separation device; 7) introducing part of the liquid phase contaminant obtained in step 6) into a gas-liquid separator; 8) introducing part of the liquid phase contaminant obtained in step 6) into the into the intermediate or the bottom part or both of the cryogenic separation device as described above in step 5); 9) removing from the gas-liquid separator a stream of liquid phase contaminant; and 10) separating the stream of liquid contaminant obtained in step 9) into a liquid product stream and a recirculation stream which is used as a motive fluid in the eductor.
A process according to claim 1, in which the feed gas stream is a natural gas stream in which the gaseous contaminants are selected from the group consisting of carbon dioxide, hydrogen sulphide and C2+-hydrocarbons.
A process according to claim 2, wherein the natural gas stream comprises between 15 and 90 vol % of carbon dioxide.
A process according to claim 2 or 3, in which the natural gas stream comprises between 0 and 25 vol % of C2+-hydrocarbons.
A process according to claim 2, in which the hydrocarbon fraction in the feed gas stream comprises at least 75 vol % of methane.
A process according to claim 1, in which the feed gas stream in step 1) has a temperature between −20 and 150° C. and a pressure between 10 and 250 bara.
A process according to claim 1, in which the cooling in step 2) is done by isenthalpic expansion, comprising isenthalpic expansion over an orifice or a valve.
A process according to claim 7, in which the feed gas stream is pre-cooled to a temperature between 15 and −35° C. before the expansion of step 2).
A process according to claim 8, in which the pre-cooling of the feed gas stream is done by heat exchange against a cold fluidum, comprising an external refrigerant.
A process according to claim 1, in which the feed gas stream is cooled in step 2) to a temperature between −40 and −100° C.
A process according to claim 1, in which all the solid contaminant present in the slurry of contaminants is melted in step 6).
A process according to claim 1, in which in step 7) the liquid phase contaminant is introduced into the bottom part of the gas-liquid separator at a level which is higher than the level at which liquid phase contaminant is removed from the bottom part of the gas-liquid separator in step 9).
A process according to claim 1, in which in step 5) the stream comprising liquid phase contaminant is introduced into the separation device at a level which is lower than the level at which the methane enriched gaseous phase is removed from the separation device in step 4).
A process for removing gaseous carbon dioxide from a feed gas stream which comprises methane and gaseous contaminants including carbon dioxide, the process comprising: 1) providing the feed gas stream; 2) cooling the feed gas stream to a temperature at which part of the carbon dioxide solidifies to obtain a slurry that comprises solid carbon dioxide, liquid phase carbon dioxide and a methane enriched gaseous phase in a conduit; 3) introducing the slurry obtained in step 2) from the conduit into the top or intermediate part of a cryogenic separation device; 4) removing from the top part of the cryogenic separation device a stream which comprises the methane enriched gaseous phase such that a slurry containing liquid and solid phases remains in the cryogenic separation device; 5) introducing a stream comprising the liquid phase carbon dioxide obtained in step 6) below into the intermediate or the bottom part or both of the cryogenic separation device to obtain a diluted slurry of carbon dioxide; 6) introducing the diluted slurry of carbon dioxide obtained in step 5) via an eductor into a heat exchanger in which solid carbon dioxide present in the diluted slurry of carbon dioxide is melted into liquid phase carbon dioxide, wherein the heat exchanger is positioned outside the separation device, and the eductor is arranged inside the cryogenic separation device; 7) introducing part of the liquid phase carbon dioxide obtained in step 6) into a gas-liquid separator; 8) introducing part of the liquid phase carbon dioxide obtained in step 6) into the into the intermediate or the bottom part or both of the cryogenic separation device as described above in step 5); 9) removing from the gas-liquid separator a stream of liquid phase carbon dioxide; and 10) separating the stream of liquid carbon dioxide obtained in step 9) into a liquid product stream and a recirculation stream which is used as a motive fluid in the eductor.

Description

The present invention concerns a process for removing gaseous contaminants, especially carbon dioxide and/or hydrogen sulphide, from a feed gas stream comprising methane and gaseous contaminants. The invention further comprises a cryogenic separation device to carry out the process, as well as products made in the process.

The removal of acid contaminants, especially carbon dioxide and/or hydrogen sulphide, from methane containing gas streams has been described in a number of publications.

In WO 03/062725 a process is described for the removal of freezable species from a natural gas stream by cooling a natural gas stream to form a slurry of solid acidic contaminants in compressed liquefied natural gas. The solids are separated from the liquid by means of a cyclone. It will be clear that a complete separation of the liquid from the solids is not easily achieved.

In U.S. Pat. No. 4,533,372 a cryogenic process is described for the removal of carbon dioxide and other acidic gases from methane-containing gas by treating the feed stream in a distillation zone and a controlled freezing zone. This is a rather complicated process requiring very specific equipment.

In U.S. Pat. No. 3,398,544 a process is described for the removal of acid contaminants from a natural gas stream by cooling to liquefy the stream and to partly solidify the stream, followed by expansion and separation of cleaned gas and liquid streams from the solids. Solid contaminants need to be removed from the separation vessel, which is a complicated process when the loss of natural gas liquid is to be minimized.

Citations (21)

US2900797A
US2996891A
US3132016A
US3398544A
US3867195A
US4533372A
US5062270A
US5120338A
US5980698A
US5730860A
US5819555A
DE19739473A1
US20020174678A1
US20020189443A1
WO2003062725A1
WO2004070297A1
US20080034789A1
WO2007030888A1
WO2008091316A1
US20110144407A1
US20110132034A1

Record as JSON

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  "publication_number": "US9396854B2",
  "country": "US",
  "kind": "B2",
  "title": "Process and apparatus for removing gaseous contaminants from gas stream comprising gaseous contaminants",
  "abstract": "The invention provides a process and a device for removing gaseous contaminants from a feed gas stream which comprises methane and gaseous contaminants, in which process the feed gas stream is cooled to obtain a slurry which comprises solid contaminant, liquid phase contaminant and a methane enriched gaseous phase, the slurry so obtained is introduced into a cryogenic separation device (4) in which from the top the methane enriched gaseous phase is removed (5), the slurry is diluted with liquid phase contaminant (6) and introduced as suction fluid into an ejector (9) via which it is passed into a heat exchanger (10) arranged outside the separation device and wherein solid contaminant is melted into liquid phase contaminant, part of the liquid phase contaminant so obtained is recycled (6) to dilute the slurry of contaminants inside the separation device and part (13) is introduced into the bottom part of the separation device, liquid phase is withdrawn (14) from the bottom part of the separation device, and part of the withdrawn liquid phase contaminant is recovered as a stream product (16) and part is recycled (17) to the ejector for use a motive fluid.",
  "claims": [
    "1. A process for removing gaseous contaminants from a feed gas stream which comprises methane and gaseous contaminants, the process comprising: 1) providing the feed gas stream; 2) cooling the feed gas stream to a temperature at which part of the contaminants solidify to obtain a slurry which comprises solid contaminant, liquid phase contaminant and a methane enriched gaseous phase in a conduit; 3) introducing the slurry obtained in step 2) from the conduit into the top or intermediate part of a cryogenic separation device; 4) removing from the top part of the cryogenic separation device a stream which comprises the methane enriched gaseous phase such that a slurry containing liquid and solid phases remains in the cryogenic separation device; 5) introducing a stream comprising the liquid phase contaminant obtained in step 6) below into the intermediate or the bottom part or both of the cryogenic separation device to obtain a diluted slurry of contaminants; 6) introducing the diluted slurry of contaminants obtained in step 5) via an eductor into a heat exchanger in which solid contaminant present in the diluted slurry of contaminants is melted into liquid phase contaminant, wherein the heat exchanger is positioned outside the separation device, and the eductor is arranged inside the cryogenic separation device; 7) introducing part of the liquid phase contaminant obtained in step 6) into a gas-liquid separator; 8) introducing part of the liquid phase contaminant obtained in step 6) into the into the intermediate or the bottom part or both of the cryogenic separation device as described above in step 5); 9) removing from the gas-liquid separator a stream of liquid phase contaminant; and 10) separating the stream of liquid contaminant obtained in step 9) into a liquid product stream and a recirculation stream which is used as a motive fluid in the eductor.",
    "2. A process according to claim 1, in which the feed gas stream is a natural gas stream in which the gaseous contaminants are selected from the group consisting of carbon dioxide, hydrogen sulphide and C2+-hydrocarbons.",
    "3. A process according to claim 2, wherein the natural gas stream comprises between 15 and 90 vol % of carbon dioxide.",
    "4. A process according to claim 2 or 3, in which the natural gas stream comprises between 0 and 25 vol % of C2+-hydrocarbons.",
    "5. A process according to claim 2, in which the hydrocarbon fraction in the feed gas stream comprises at least 75 vol % of methane.",
    "6. A process according to claim 1, in which the feed gas stream in step 1) has a temperature between −20 and 150° C. and a pressure between 10 and 250 bara.",
    "7. A process according to claim 1, in which the cooling in step 2) is done by isenthalpic expansion, comprising isenthalpic expansion over an orifice or a valve.",
    "8. A process according to claim 7, in which the feed gas stream is pre-cooled to a temperature between 15 and −35° C. before the expansion of step 2).",
    "9. A process according to claim 8, in which the pre-cooling of the feed gas stream is done by heat exchange against a cold fluidum, comprising an external refrigerant.",
    "10. A process according to claim 1, in which the feed gas stream is cooled in step 2) to a temperature between −40 and −100° C.",
    "11. A process according to claim 1, in which all the solid contaminant present in the slurry of contaminants is melted in step 6).",
    "12. A process according to claim 1, in which in step 7) the liquid phase contaminant is introduced into the bottom part of the gas-liquid separator at a level which is higher than the level at which liquid phase contaminant is removed from the bottom part of the gas-liquid separator in step 9).",
    "13. A process according to claim 1, in which in step 5) the stream comprising liquid phase contaminant is introduced into the separation device at a level which is lower than the level at which the methane enriched gaseous phase is removed from the separation device in step 4).",
    "14. A process for removing gaseous carbon dioxide from a feed gas stream which comprises methane and gaseous contaminants including carbon dioxide, the process comprising: 1) providing the feed gas stream; 2) cooling the feed gas stream to a temperature at which part of the carbon dioxide solidifies to obtain a slurry that comprises solid carbon dioxide, liquid phase carbon dioxide and a methane enriched gaseous phase in a conduit; 3) introducing the slurry obtained in step 2) from the conduit into the top or intermediate part of a cryogenic separation device; 4) removing from the top part of the cryogenic separation device a stream which comprises the methane enriched gaseous phase such that a slurry containing liquid and solid phases remains in the cryogenic separation device; 5) introducing a stream comprising the liquid phase carbon dioxide obtained in step 6) below into the intermediate or the bottom part or both of the cryogenic separation device to obtain a diluted slurry of carbon dioxide; 6) introducing the diluted slurry of carbon dioxide obtained in step 5) via an eductor into a heat exchanger in which solid carbon dioxide present in the diluted slurry of carbon dioxide is melted into liquid phase carbon dioxide, wherein the heat exchanger is positioned outside the separation device, and the eductor is arranged inside the cryogenic separation device; 7) introducing part of the liquid phase carbon dioxide obtained in step 6) into a gas-liquid separator; 8) introducing part of the liquid phase carbon dioxide obtained in step 6) into the into the intermediate or the bottom part or both of the cryogenic separation device as described above in step 5); 9) removing from the gas-liquid separator a stream of liquid phase carbon dioxide; and 10) separating the stream of liquid carbon dioxide obtained in step 9) into a liquid product stream and a recirculation stream which is used as a motive fluid in the eductor."
  ],
  "description_excerpt": "The present invention concerns a process for removing gaseous contaminants, especially carbon dioxide and/or hydrogen sulphide, from a feed gas stream comprising methane and gaseous contaminants. The invention further comprises a cryogenic separation device to carry out the process, as well as products made in the process.\n\nThe removal of acid contaminants, especially carbon dioxide and/or hydrogen sulphide, from methane containing gas streams has been described in a number of publications.\n\nIn WO 03/062725 a process is described for the removal of freezable species from a natural gas stream by cooling a natural gas stream to form a slurry of solid acidic contaminants in compressed liquefied natural gas. The solids are separated from the liquid by means of a cyclone. It will be clear that a complete separation of the liquid from the solids is not easily achieved.\n\nIn U.S. Pat. No. 4,533,372 a cryogenic process is described for the removal of carbon dioxide and other acidic gases from methane-containing gas by treating the feed stream in a distillation zone and a controlled freezing zone. This is a rather complicated process requiring very specific equipment.\n\nIn U.S. Pat. No. 3,398,544 a process is described for the removal of acid contaminants from a natural gas stream by cooling to liquefy the stream and to partly solidify the stream, followed by expansion and separation of cleaned gas and liquid streams from the solids. Solid contaminants need to be removed from the separation vessel, which is a complicated process when the loss of natural gas liquid is to be minimized.",
  "cpc": [
    "H01F 5/04",
    "B01D 2256/24",
    "B01D 53/002",
    "C10L 3/10",
    "C10L 3/102",
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    "F25J 2205/02",
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    "F25J 2270/12",
    "F25J 2270/60",
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    "F25J 3/0635",
    "F25J 3/067",
    "H01F 27/2895",
    "H01R 13/6633",
    "H01R 13/6658",
    "H01R 24/64"
  ],
  "ipc": [
    "B01D 9/04",
    "F25J 3/08",
    "H01R 24/58",
    "C10L 3/10",
    "F25J 3/06",
    "H01F 27/28",
    "H01F 5/04"
  ],
  "assignees": [
    "Shell Oil Co"
  ],
  "inventors": [
    "Henricus Abraham GEERS",
    "Helmar Van Santen"
  ],
  "filing_date": "2009-08-27",
  "publication_date": "2016-07-19",
  "grant_date": "2016-07-19",
  "priority_date": "2008-08-29",
  "application_number": "US-200913061435-A",
  "family_id": "40377403",
  "cited_by_count": 7,
  "citations": [
    "US2900797A",
    "US2996891A",
    "US3132016A",
    "US3398544A",
    "US3867195A",
    "US4533372A",
    "US5062270A",
    "US5120338A",
    "US5980698A",
    "US5730860A",
    "US5819555A",
    "DE19739473A1",
    "US20020174678A1",
    "US20020189443A1",
    "WO2003062725A1",
    "WO2004070297A1",
    "US20080034789A1",
    "WO2007030888A1",
    "WO2008091316A1",
    "US20110144407A1",
    "US20110132034A1"
  ]
}

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