AU2016236357B2 - Process for producing a purified gas stream from natural gas wells - Google Patents
Process for producing a purified gas stream from natural gas wells Download PDFInfo
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- AU2016236357B2 AU2016236357B2 AU2016236357A AU2016236357A AU2016236357B2 AU 2016236357 B2 AU2016236357 B2 AU 2016236357B2 AU 2016236357 A AU2016236357 A AU 2016236357A AU 2016236357 A AU2016236357 A AU 2016236357A AU 2016236357 B2 AU2016236357 B2 AU 2016236357B2
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- gas stream
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- xylene
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- 239000007789 gas Substances 0.000 title claims abstract description 87
- 238000000034 method Methods 0.000 title claims abstract description 41
- 239000002343 natural gas well Substances 0.000 title description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims abstract description 78
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 78
- 239000007788 liquid Substances 0.000 claims abstract description 77
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 44
- 238000010521 absorption reaction Methods 0.000 claims abstract description 43
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 22
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 22
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims abstract description 20
- 150000001491 aromatic compounds Chemical class 0.000 claims abstract description 18
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000003345 natural gas Substances 0.000 claims abstract description 13
- 150000003335 secondary amines Chemical class 0.000 claims abstract description 11
- 150000003512 tertiary amines Chemical class 0.000 claims abstract description 11
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 claims description 40
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical group CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 37
- IVSZLXZYQVIEFR-UHFFFAOYSA-N m-xylene Chemical group CC1=CC=CC(C)=C1 IVSZLXZYQVIEFR-UHFFFAOYSA-N 0.000 claims description 34
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 claims description 26
- 229940078552 o-xylene Drugs 0.000 claims description 18
- 238000001816 cooling Methods 0.000 claims description 17
- 229930195733 hydrocarbon Natural products 0.000 claims description 15
- 150000002430 hydrocarbons Chemical class 0.000 claims description 15
- 150000001875 compounds Chemical class 0.000 claims description 11
- 125000004432 carbon atom Chemical group C* 0.000 claims description 10
- 238000000605 extraction Methods 0.000 claims description 10
- 238000005201 scrubbing Methods 0.000 claims description 5
- 239000004215 Carbon black (E152) Substances 0.000 claims description 2
- 238000000926 separation method Methods 0.000 claims description 2
- 239000008096 xylene Substances 0.000 abstract description 8
- 150000003738 xylenes Chemical class 0.000 abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 description 12
- LVTYICIALWPMFW-UHFFFAOYSA-N diisopropanolamine Chemical compound CC(O)CNCC(C)O LVTYICIALWPMFW-UHFFFAOYSA-N 0.000 description 11
- 102100032373 Coiled-coil domain-containing protein 85B Human genes 0.000 description 10
- 101000868814 Homo sapiens Coiled-coil domain-containing protein 85B Proteins 0.000 description 10
- 239000002904 solvent Substances 0.000 description 10
- 239000000356 contaminant Substances 0.000 description 8
- 239000003507 refrigerant Substances 0.000 description 7
- PVXVWWANJIWJOO-UHFFFAOYSA-N 1-(1,3-benzodioxol-5-yl)-N-ethylpropan-2-amine Chemical compound CCNC(C)CC1=CC=C2OCOC2=C1 PVXVWWANJIWJOO-UHFFFAOYSA-N 0.000 description 6
- QMMZSJPSPRTHGB-UHFFFAOYSA-N MDEA Natural products CC(C)CCCCC=CCC=CC(O)=O QMMZSJPSPRTHGB-UHFFFAOYSA-N 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 6
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 5
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 5
- 239000003949 liquefied natural gas Substances 0.000 description 5
- 150000001412 amines Chemical class 0.000 description 4
- -1 oxylene Natural products 0.000 description 4
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 3
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 2
- BFSVOASYOCHEOV-UHFFFAOYSA-N 2-diethylaminoethanol Chemical compound CCN(CC)CCO BFSVOASYOCHEOV-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 2
- OPKOKAMJFNKNAS-UHFFFAOYSA-N N-methylethanolamine Chemical compound CNCCO OPKOKAMJFNKNAS-UHFFFAOYSA-N 0.000 description 2
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical class CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 2
- 239000012190 activator Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- LHIJANUOQQMGNT-UHFFFAOYSA-N aminoethylethanolamine Chemical compound NCCNCCO LHIJANUOQQMGNT-UHFFFAOYSA-N 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 229940031098 ethanolamine Drugs 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1456—Removing acid components
- B01D53/1462—Removing mixtures of hydrogen sulfide and carbon dioxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/002—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by condensation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1487—Removing organic compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1493—Selection of liquid materials for use as absorbents
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
- C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
- C10L3/10—Working-up natural gas or synthetic natural gas
- C10L3/101—Removal of contaminants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
- C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
- C10L3/10—Working-up natural gas or synthetic natural gas
- C10L3/101—Removal of contaminants
- C10L3/102—Removal of contaminants of acid contaminants
- C10L3/103—Sulfur containing contaminants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
- C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
- C10L3/10—Working-up natural gas or synthetic natural gas
- C10L3/101—Removal of contaminants
- C10L3/102—Removal of contaminants of acid contaminants
- C10L3/104—Carbon dioxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
- B01D2252/20—Organic absorbents
- B01D2252/204—Amines
- B01D2252/20426—Secondary amines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
- B01D2252/20—Organic absorbents
- B01D2252/204—Amines
- B01D2252/20431—Tertiary amines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
- B01D2252/20—Organic absorbents
- B01D2252/205—Other organic compounds not covered by B01D2252/00 - B01D2252/20494
- B01D2252/2056—Sulfur compounds, e.g. Sulfolane, thiols
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2256/00—Main component in the product gas stream after treatment
- B01D2256/24—Hydrocarbons
- B01D2256/245—Methane
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/30—Sulfur compounds
- B01D2257/304—Hydrogen sulfide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/50—Carbon oxides
- B01D2257/504—Carbon dioxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
- B01D2257/702—Hydrocarbons
- B01D2257/7027—Aromatic hydrocarbons
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/65—Employing advanced heat integration, e.g. Pinch technology
- B01D2259/652—Employing advanced heat integration, e.g. Pinch technology using side coolers
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L2290/00—Fuel preparation or upgrading, processes or apparatus therefore, comprising specific process steps or apparatus units
- C10L2290/06—Heat exchange, direct or indirect
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L2290/00—Fuel preparation or upgrading, processes or apparatus therefore, comprising specific process steps or apparatus units
- C10L2290/48—Expanders, e.g. throttles or flash tanks
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L2290/00—Fuel preparation or upgrading, processes or apparatus therefore, comprising specific process steps or apparatus units
- C10L2290/54—Specific separation steps for separating fractions, components or impurities during preparation or upgrading of a fuel
- C10L2290/542—Adsorption of impurities during preparation or upgrading of a fuel
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Gas Separation By Absorption (AREA)
Abstract
The invention relates to a process for producing a purified gas stream from a feed gas stream comprising natural gas, carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, xylenes. In the process the feed gas stream is contacted with absorbing liquid comprising sulfolane and a secondary or tertiary amine in an absorption column. The temperature of the absorbing liquid is reduced at an intermediate section of the absorption column. A loaded absorbing liquid and a depleted gas stream are obtained. Optionally the gas stream is cooled and de-pressurized, and flash gas is obtained. A single stage flesh vessel can be used, while it is not necessary to use a scrubber or de (m)ethanizer. Flash gas comprising less than 3 ppmv BTEX can be obtained. This flash gas can be subjected to liquefaction to obtain LNG.
Description
Field of the invention
The invention relates to a process for producing a purified gas stream from a feed gas stream comprising contaminants .
Background to the invention
Gas streams from natural gas wells typically comprise contaminants such as carbon dioxide, hydrogen sulphide, and aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene that need to be removed before the gas streams can be further used.
Processes for removing hydrogen sulfide, carbon dioxide and aromatic hydrocarbons from a gas stream are known in the art. Such processes typically comprise an absorption step for removing hydrogen sulfide, carbon dioxide and aromatic hydrocarbons from the gaseous feed stream by contacting such gaseous feed stream with a solvent, for example an amine solvent, in an absorption column. Thus a purified gaseous stream is obtained and a solvent loaded with contaminants. The loaded solvent is typically regenerated in a stripper to obtain a gas stream comprising contaminants and a lean solvent that is recycled to the absorption column.
BTX is often used as acronym for benzene, toluene, and xylenes (e.g. o-xylene, m-xylene and/or p-xylene). BTEX is often used as acronym for benzene, toluene, ethylbenzene, and xylenes (e.g. o-xylene, m-xylene and/or p-xylene).
-1WO 2016/150827
PCT/EP2016/055871
When producing LNG (liquefied natural gas), BTEX is removed prior to liquefaction to avoid freezing. When the level of BTEX in the gas is too high, tubes may become plugged during liquefaction. Generally it is preferred to have a BTEX concentration in the gas of at most 3 ppmv (parts per million by volume) before liquefaction.
W02007003618 describes a process in which benzene, toluene, o-xylene, m-xylene and p-xylene (BTX) are removed by means of an absorbing liquid comprising a physical solvent. In this step hydrogen sulfide and carbon dioxide are also removed to a large extent. In a preferred process a mixture of sulfolane, a secondary or tertiary amine, and water is used as absorbing liquid.
After benzene, toluene, and xylenes have been removed to a large extend by means of an absorbing liquid, it is necessary to lower the their concentration further. This is typically performed by means of a scrubber column, an adsorber, an extraction unit, or another type of BTEX or BTX removal unit. In such a second step it is sometimes also possible to remove hydrocarbons with more than 5 carbon atoms (C5+) from the gas.
There is a need for an improved process in which the removal of benzene, toluene, and xylenes is more efficient, without disturbing the removal of hydrogen sulfide and carbon dioxide.
Summary of the invention
It has now been found that the efficiency of the removal of benzene, toluene, and xylenes can be increased by contacting the gas with a specific absorption liquid and reducing the temperature in the absorption column.
2016236357 25 Feb 2019
In one aspect there is provided a process for producing a purified gas stream from a feed gas stream comprising natural gas, carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, ethylbenzene, oxylene, m-xylene and p-xylene, the process comprising the following steps:
(a) contacting the feed gas stream with absorbing liquid comprising sulfolane and a secondary or tertiary amine in an absorption column, and reducing the temperature of the absorbing liquid at an intermediate section of the absorption column, to obtain loaded absorbing liquid comprising carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, o-xylene, m-xylene and p-xylene, and a gas stream depleted of these compounds;
(b) cooling and de-pressurizing at least a part of the gas stream obtained in step (a) to obtain a liquid comprising aromatic compounds selected from the group of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, and flash gas depleted of these compounds.
Disclosed herein is a process wherein a purified gas stream is produced from a feed gas stream comprising natural gas, carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, ethylbenzene, oxylene, m-xylene and p-xylene. The process comprises the following steps:
(a) contacting the feed gas stream with absorbing liquid comprising sulfolane and a secondary or tertiary amine in an absorption column, and reducing the temperature of the absorbing liquid at an intermediate section of the absorption column, to obtain loaded absorbing liquid comprising carbon dioxide, hydrogen sulphide, and aromatic compounds
AH26(22159758_2):RTK
3a
2016236357 25 Feb 2019 selected from the group of benzene, toluene, o-xylene, m-xylene and p-xylene, and a gas stream depleted of these compounds;
(b) cooling and de-pressurizing at least a part of the gas stream obtained in step (a) to obtain a liquid comprising aromatic compounds selected from the group of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, and flash gas depleted of these compounds.
An advantage of the process according to the invention is that the efficiency of the removal of benzene, toluene, and xylenes (BTX) has been increased in step (a).
Step (b) has as additional advantage that the efficiency of the removal of benzene, toluene, ethylbenzene, o-xylene, mxylene and p-xylene (BTEX) is improved.
Another advantage is that NGL and aromatics can be removed by the cooling and de-pressurization of step (b).
AH26(22159758_2):RTK
WO 2016/150827
PCT/EP2016/055871
Step (b) can be performed in one or more single stage flash vessels. There is no need to use a scrubbing column, a deethanizer or de-methanizer, an adsorber, or an extraction unit. Apart from one or more single stage flash vessels, there is no need to use another BTX or BTEX removal unit in step (b). And the NGL removal unit of an LNG plant can be significantly simplified. NGL stands for Natural Gas liquids, which are associated hydrocarbons such as C2H6, C3H8, nC4H10, and pentanes.
A further advantage is that in step (b) flash gas comprising less than 3 ppmv BTEX can be obtained. This flash gas can be subjected to liquefaction to obtain LNG. Detailed description of the invention
In the process according to the invention, a purified gas stream is produced from a feed gas stream comprising natural gas, carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene. The process comprises the following steps:
(a) contacting the feed gas stream with absorbing liquid comprising sulfolane and a secondary or tertiary amine in an absorption column, and reducing the temperature of the absorbing liquid at an intermediate section of the absorption column, to obtain loaded absorbing liquid comprising carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, o-xylene, m-xylene and p-xylene, and a gas stream depleted of these compounds;
-4WO 2016/150827
PCT/EP2016/055871 (b) cooling and de-pressurizing at least a part of the gas stream obtained in step (a) to obtain a liquid comprising aromatic compounds selected from the group of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, and flash gas depleted of these compounds.
The feed gas stream comprises natural gas, carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene. The feed gas stream may also comprise hydrocarbons with more than 5 carbon atoms (C5+).
Natural gas is a general term that is applied to mixtures of light hydrocarbons and optionally other gases (nitrogen, carbon dioxide, helium) derived from natural gas wells. The main component of natural gas is methane.
Further, often ethane, propane and butane are present. In some cases (small) amounts of higher hydrocarbons may be present, often indicated as natural gas liquids or condensates. When produced together with oil, the natural gas is usually called associated gas. Other compounds that may be present as contaminants in natural gas in varying amounts include carbon dioxide, hydrogen sulphide, and aromatic compounds.
The feed gas stream may comprise H2S, for example in the range of from 1 ppmv to 10 vol%, based on the total feed gas stream. The feed gas stream may also comprise carbon dioxide, for example in the range of from 0 to 40 vol%, based on the total feed gas stream.
In case the feed gas stream additionally comprises hydrocarbons with more than 5 carbon atoms, the loaded absorbing liquid obtained in step (a) also additionally comprises hydrocarbons with more than 5 carbon atoms and
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PCT/EP2016/055871 the liquid obtained in step (b) additionally comprises hydrocarbons with more than 5 carbon atoms.
Preferably the absorbing liquid is used in step (a) to remove contaminants by transferring contaminants from the feed gas stream to the absorbing liquid. This results in an absorbing liquid loaded with contaminants. The loaded absorbing liquid may be regenerated by contacting with a regeneration gas.
The absorbing liquid comprises sulfolane and a secondary or tertiary amine. Sulfolane is a physical solvent. The secondary or tertiary amine is a chemical solvent. Preferably the absorbing liquid additionally comprises another solvent, most preferably water.
Preferably the amount of sulfolane is in the range of from 10 to 80, more preferably from 15 to 50, still more preferably from 20 to 35 parts by weight, based on the total absorbing liquid. The remainder of the absorbing liquid is secondary or tertiary amine and suitably another solvent, preferably water.
Examples of suitable secondary or tertiary amines are an amine compound derived from ethanol amine, more especially DIPA (di-isopropanolamine), DEA, MMEA (monomethyl-ethanolamine), MDEA, or DEMEA (diethylmonoethanolamine), preferably DIPA or MDEA, most preferably DIPA.
The absorbing liquid may further comprise a so-called activator compound. Suitable activator compounds are piperazine, methyl-ethanolamine, or (2-aminoethyl)ethanolamine, especially piperazine. A preferred absorbing liquid comprises sulfolane, MDEA and piperazine.
For the current process a highly preferred absorbing liquid comprises sulfolane, water and DIPA.
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The absorbing liquid typically comprises water, preferably in the range of from 15 to 45 parts by weight, more preferably of from 15 to 40 parts by weight of water.
In step (a) the temperature of the absorbing liquid is reduced at an intermediate section of the absorption column. Preferably the temperature of the absorbing liquid is reduced by means of removing absorbing liquid from the absorption column, cooling the removed absorbing liquid, and feeding cooled absorbing liquid back to the absorbing column .
Most preferably cooled liquid is fed back to the absorbing column at a level lower than at which absorbing liquid to be cooled is removed from the absorbing column.
But it can also be fed back at the same level, or at a level higher than at which absorbing liquid to be cooled is removed from the absorbing column.
In a preferred embodiment the temperature of the absorbing liquid is reduced by means of inter-stage cooling. The temperature of the absorbing liquid may be reduced by means of an intercooler. An intercooler can be obtained, for example, from Black & Veatch. An example of an absorption column with inter-stage cooling is provided in Figure 1.
In step (b) gas obtained in step (a) preferably is cooled to a temperature in the range of between -30 and 100 °C, preferably between -35 and -100 °C, more preferably between -35 and -70 °C, even more preferably between -35 and -65 °C, before de-pressurizing.
Preferably depressurization in step (b) is performed in one or more single stage flash vessels. Step (b) may be performed with a simple knock out vessel. Suitable flash vessels can be obtained, for example, from Linde Star LNG.
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After step (b) it is not necessary to use a scrubbing column, a de-ethanizer or de-methanizer, an adsorber, or an extraction unit.
The flash gas obtained in step (b) may be (partially) subjected to liquefaction.
According to an embodiment, the flash gas obtained in step (b) comprises less than 3 ppmv BTEX and is passed to a liquefaction unit, in particular to one or more heat exchangers comprised by the liquefaction unit, without being passed through any further BTEX removal equipment and/or hydrocarbon extraction/separation unit (NGL extraction), in particular without being passed through a scrubbing column, a de-ethanizer or de-methanizer, an adsorber and an extraction unit.
Passing the flash gas to the liquefaction unit, in particular to one or more heat exchangers comprised by the liquefaction unit, may comprise passing the flash gas through a water removal unit and/or a mercury removal unit.
The liquefaction unit may comprise a pre-cooling heat exchanger and a main cryogenic heat exchanger. Both the pre-cooling heat exchanger and/or the main cryogenic heat exchanger may be formed by one or more parallel and/or serial sub-heat exchangers.
The liquefaction unit may use a C3-MR process in which the refrigerant used for the pre-cooling heat exchanger is mainly propane and the refrigerant used for the main cryogenic heat exchanger is a mixed refrigerant. The liquefaction unit may use a DMR process in which the refrigerant used for the pre-cooling heat exchanger is a first mixed refrigerant and the refrigerant used for the main cryogenic heat exchanger is a second mixed refrigerant.
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Optionally a part of the flash gas obtained in step (b) is recycled to the absorption column. When a part of the flash gas is recycled to step (a), the feed gas stream and the flash gas are contacted with the absorbing liquid in the absorption column.
Figure 1
Figure 1 shows an example of an absorption column with inter-stage cooling. A feed gas stream enters the absorption column via line 1. A gas stream depleted of carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, o-xylene, mxylene and p-xylene leaves the absorption column via line 2. This gas is subjected to step (b), and optionally additionally to liquefaction.
Absorbing liquid, which may be regenerated absorbing liquid, enters the absorption column via line 3. The absorbing liquid entering via line 3 does not comprise or is lean with regard to carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, o-xylene, m-xylene and p-xylene.
The absorption of carbon dioxide is exothermal and the temperature of the absorbing liquid increases while flowing down the column. The temperature of the absorbing liquid is at an intermediate section of the absorption column. Warm absorbing liquid is removed from the absorption column via line 5 and after cooling fed back to the absorption column via line 6.
Examples
Experiments according to the present invention were performed with a feed gas stream comprising natural gas, carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, ethylbenzene,
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PCT/EP2016/055871 o-xylene, m-xylene and p-xylene. The feed gas stream was contacted with absorbing liquid comprising sulfolane and a secondary or tertiary amine in an absorption column.
In Experiment 1 the amine was MDEA, and the absorption 5 liquid also comprised piperazine. Step (b) of the current process was not performed. The table below shows that the absorption liquid comprising water, sulfolane, MDEA and piperazine results in very good BTX removal.
In Experiment 2 the amine was DIPA. Step (b) of the 10 current process was not performed. The table below shows that the absorption liquid comprising water, sulfolane and DIPA results in excellent BTX removal.
In Experiment 3 the amine was DIPA. Step (b) of the current process was performed. The table below shows that the absorption liquid comprising water, sulfolane and DIPA results in an even better BTX removal than Experiment 2.
| Experiment | Absorption liquid | BTX (% mol out | 1 mol in) |
| 1 (step a) | water, sulfolane, MDEA and piperazine | 40% | |
| 2 (step a) | water, sulfolane and DIPA | 23% | |
| 3 (step a and b) | water, sulfolane and DIPA | 16% |
For step (b) the influence of the cooling temperature 20 before de-pressurizing was investigated. The BTX removal of step (b) increases when the gas is cooled deeper.
| Flash vessel inlet | BTX removed (%) |
| temperature (°C ) |
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| -60 | 80% |
| -51 | 73% |
| -45 | 59% |
| -40 | 43% |
| -30 | 7% |
The person skilled in the art will readily understand that many modifications may be made without departing from the scope of the invention. For instance, it is noted here that step (b) is an optional step. Furthermore, where the word step or steps is used in this text, it will be understood that this is not done to imply a specific order. The steps may be applied in any suitable order, including simultaneously.
Claims (18)
1. A process for producing a purified gas stream from a feed gas stream comprising natural gas, carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, the process comprising the following steps:
(a) contacting the feed gas stream with absorbing liquid comprising sulfolane and a secondary or tertiary amine in an absorption column, and reducing the temperature of the absorbing liquid at an intermediate section of the absorption column, to obtain loaded absorbing liquid comprising carbon dioxide, hydrogen sulphide, and aromatic compounds selected from the group of benzene, toluene, o-xylene, mxylene and p-xylene, and a gas stream depleted of these compounds;
(b) cooling and de-pressurizing at least a part of the gas stream obtained in step (a) to obtain a liquid comprising aromatic compounds selected from the group of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene, and flash gas depleted of these compounds.
2. The process according to claim 1, wherein the level at which absorbing liquid enters the absorption column and the level at which feed gas stream enters the absorption column are separated by a height H, and the temperature of the absorbing liquid is reduced at a level lower than 0.1 H from the level at which absorbing liquid enters the absorption column and higher than 0.1 H from the level at which feed gas stream enters the absorption column.
3. The process according to claim 2, wherein the temperature of the absorbing liquid is reduced at a level lower than 0.2 H from the level at which absorbing liquid enters the absorption column
AH26(22159758_2):RTK
2016236357 25 Feb 2019 and higher than 0.2 H from the level at which feed gas stream enters the absorption column.
4. The process of claim 2 or 3, wherein the temperature of the absorbing liquid is reduced at a level lower than 0.3 H from the level at which absorbing liquid enters the absorption column and higher than 0.3 H from the level at which feed gas stream enters the absorption column.
5. The process according to any one of the preceding claims, wherein the temperature of the absorbing liquid is reduced by means of removing absorbing liquid from the absorption column, cooling the removed absorbing liquid, and feeding cooled absorbing liquid back to the absorbing column.
6. The process according to any one of the preceding claims, wherein the temperature of the absorbing liquid is reduced by means of inter-stage cooling.
7. The process according to any one of the preceding claims, wherein the feed gas stream additionally comprises hydrocarbons with more than 5 carbon atoms, and the loaded absorbing liquid obtained in step (a) additionally comprises hydrocarbons with more than 5 carbon atoms.
8. The process according to any one of the preceding claims wherein step (b) is performed, and wherein the feed gas stream additionally comprises hydrocarbons with more than 5 carbon atoms, and the loaded absorbing liquid obtained in step (a) additionally comprises hydrocarbons with more than 5 carbon atoms, and the liquid obtained in step (b) additionally comprises hydrocarbons with more than 5 carbon atoms.
9. The process according to any one of the preceding claims wherein in step (b) at least a part of the gas stream obtained
AH26(22159758_2):RTK
2016236357 25 Feb 2019 in step (a) is cooled to a temperature in the range of between 30 and -100 °C before de-pressurizing.
10. The process according to any one of the preceding claims wherein in step (b) at least a part of the gas stream obtained in step (a) is cooled to a temperature in the range of between -35 and -100°C before de-pressurizing.
11. The process according to any one of the preceding claims wherein in step (b) at least a part of the gas stream obtained in step (a) is cooled to a temperature in the range of between 35 and -70°C before de-pressurizing.
12. The process according to any one of the preceding claims wherein in step (b) at least a part of the gas stream obtained in step (a) is cooled to a temperature in the range of between 35 and -65°C before de-pressurizing.
13. The process according to any one of the preceding claims wherein the depressurization in step (b) is performed in one or more single stage flash vessels.
14. The process according to any one of the preceding claims wherein in step (b), no use is made of a scrubbing column, a deethanizer or de-methanizer, an adsorber, or an extraction unit.
15. The process according to any one of the preceding claims wherein the flash gas obtained in step (b) is subjected to liguefaction .
16. The process according to claim 15, wherein a part of the flash gas obtained in step (b) is recycled to step (a), whereby said part of the flash gas and the feed gas stream are contacted with the absorbing liguid.
AH26(22159758_2):RTK
2016236357 25 Feb 2019
17. The process according to any one of the preceding claims, wherein the flash gas obtained in step (b) comprises less than 3 ppmv BTEX and is passed to a liquefaction unit without being passed through any further BTEX removal equipment and/or hydrocarbon extraction/separation unit (NGL extraction).
18. The process according to claim 17, wherein the flash gas obtained in step (b) comprises less than 3 ppmv BTEX and is passed to a liquefaction unit without being passed through a scrubbing column, a de-ethanizer or de-methanizer, an adsorber and an extraction unit.
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| EP15160094 | 2015-03-20 | ||
| EP15160094.7 | 2015-03-20 | ||
| PCT/EP2016/055871 WO2016150827A1 (en) | 2015-03-20 | 2016-03-17 | Process for producing a purified gas stream from natural gas wells |
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| EA202190312A1 (en) | 2018-07-18 | 2021-04-21 | Шелл Интернэшнл Рисерч Маатсхаппий Б.В. | METHOD AND SYSTEM OF GAS PURIFICATION |
| CN109364720A (en) * | 2018-09-21 | 2019-02-22 | 湖南顶立科技有限公司 | The purification system and its application method of discarded circuit board cracking gas |
| CN109251775A (en) * | 2018-10-10 | 2019-01-22 | 赵崇来 | A kind of new energy methane purifying device |
| EP3943851A1 (en) | 2020-07-22 | 2022-01-26 | Shell Internationale Research Maatschappij B.V. | Method and system for natural gas liquefaction with improved removal of heavy hydrocarbons |
| CA3199448A1 (en) | 2020-10-26 | 2022-05-05 | Shell Internationale Research Maatschappij B.V. | Compact system and method for the production of liquefied natural gas |
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| WO2004026441A1 (en) * | 2002-09-17 | 2004-04-01 | Fluor Corporation | Configurations and methods of acid gas removal |
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| WO2007003618A1 (en) * | 2005-07-04 | 2007-01-11 | Shell Internationale Research Maatschappij B.V. | Process for producing a gas stream depleted of mercaptans |
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| EP2789957A1 (en) * | 2013-04-11 | 2014-10-15 | Shell Internationale Research Maatschappij B.V. | Method of liquefying a contaminated hydrocarbon-containing gas stream |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| EP2869909A1 (en) * | 2012-07-03 | 2015-05-13 | Shell Internationale Research Maatschappij B.V. | Process for deep contaminent removal of gas streams |
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Patent Citations (6)
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| GB2147984A (en) * | 1983-10-11 | 1985-05-22 | Exxon Production Research Co | A process for the liquefaction of natural gas |
| US20060032377A1 (en) * | 2002-07-03 | 2006-02-16 | Satish Reddy | Split flow process and apparatus |
| WO2004026441A1 (en) * | 2002-09-17 | 2004-04-01 | Fluor Corporation | Configurations and methods of acid gas removal |
| WO2007003618A1 (en) * | 2005-07-04 | 2007-01-11 | Shell Internationale Research Maatschappij B.V. | Process for producing a gas stream depleted of mercaptans |
| WO2007107004A1 (en) * | 2006-03-23 | 2007-09-27 | University Of Regina | Heat recovery gas absorption process |
| EP2789957A1 (en) * | 2013-04-11 | 2014-10-15 | Shell Internationale Research Maatschappij B.V. | Method of liquefying a contaminated hydrocarbon-containing gas stream |
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| EA201792081A1 (en) | 2018-04-30 |
| EA038262B1 (en) | 2021-07-30 |
| WO2016150827A1 (en) | 2016-09-29 |
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