Classifications

• • 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
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  • 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 OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • 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
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  • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
  • B01D5/0003—Condensation of vapours; Recovering volatile solvents by condensation by using heat-exchange surfaces for indirect contact between gases or vapours and the cooling medium
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  • 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
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  • B01D—SEPARATION
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  • 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
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  • 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
• • 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 OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • 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
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  • 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
  • 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
• • 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
  • B01D2252/204—Amines
  • B01D2252/20436—Cyclic amines
  • B01D2252/20447—Cyclic amines containing a piperazine-ring
• • 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
  • B01D2252/20478—Alkanolamines
  • B01D2252/20489—Alkanolamines with two or more hydroxyl groups
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/10—Single element gases other than halogens
  • B01D2257/102—Nitrogen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/60—Heavy metals or heavy metal compounds
  • B01D2257/602—Mercury or mercury compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/80—Water
• • 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
  • B01D53/1425—Regeneration of liquid absorbents
• • 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
  • B01D53/14—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
  • B01D53/1468—Removing hydrogen sulfide
• • 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
  • B01D53/1475—Removing carbon dioxide
• • 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 OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L2290/00—Fuel preparation or upgrading, processes or apparatus therefore, comprising specific process steps or apparatus units
  • C10L2290/08—Drying or removing water
• • 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 OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L2290/00—Fuel preparation or upgrading, processes or apparatus therefore, comprising specific process steps or apparatus units
  • C10L2290/44—Deacidification step, e.g. in coal enhancing
• • 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 OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • 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
  • C10L2290/541—Absorption of impurities during preparation or upgrading of a fuel

Definitions

• the present invention relates to a method for producing a deacidified fluid stream, in particular for producing deacidified natural gas, with a low methanol content.
• natural gas which is produced after production, contains various other components such as other hydrocarbons, water and acidic gases such as CO2, H 2 S or mercaptans.
• Crude gas must be purified as a so-called sales gas before it is sold, so that it meets the specifications and requirements of the customers and the sales companies.
• Drying also guarantees a constant calorific value of the gas when it is fed into the public gas network.
• acidic gases such as CO2, H 2 S and mercaptans have to be removed as they are corrosive and can lead to corrosion damage in the pipes or equipment of the raw gas processing plants.
• acidic gases such as CO2, H 2 S and mercaptans
• CO2 and H 2 S environmental pollutants they are the main cause of so-called acid rain.
• LNG liquefied natural gas
• the raw gas therefore generally goes through a large number of purification steps before it is fed into the natural gas network as sales gas.
• the raw gas is usually cooled so that water and the constituents that form the natural gas condensate, such as longer-chain alkanes and aromatics, condense out.
• the condensed liquids ie the natural gas condensate and water, can be separated from the non-liquefied natural gas.
• Water and natural gas condensate are usually separated off at or near the production site.
• methanol is usually added to the natural gas after the water and natural gas condensate have been separated off and before being transported to a natural gas processing plant. Methanol acts as an inhibitor against the formation of methane hydrates in raw gas.
• a natural gas processing plant generally includes one or more of the following steps:
• the raw gas is generally brought into contact with an absorbent which absorbs at least some of the acid gases, so that a deacidified natural gas and an absorbent loaded with the acid gases are obtained.
• the methanol present in the raw gas is generally not completely co-absorbed in the absorbent, so that the deacidified natural gas still contains certain residual amounts of methanol before it is fed to the dewatering stage (ii). This can be the case in particular if the absorbent itself contains residual amounts of methanol. Residual amounts of methanol can be contained in the absorbent if regenerated absorbent is used for deacidification, from which methanol has not been completely removed.
• the drainage can be configured, for example, as pressure swing adsorption (or pressure swing adsorption (PSA)), preferably as temperature swing adsorption (TSA) or as glycol drying.
• PSA pressure swing adsorption
• TSA temperature swing adsorption
• a 4 A molecular sieve must be used instead of a 3 A molecular sieve in the presence of residual amounts of methanol, which in addition to water and methanol also other components such as H2S and ethane are absorbed.
• the absorption of methanol competes with the preferred absorption of water.
• Methanol can also lead to faster coking of the molecular sieve when the molecular sieve is regenerated by increasing the temperature.
• methanol can be carried over to several parts of the system, since this separates during the regeneration of the drying agent Water also contains methanol.
• methanol generally requires a further aftertreatment of the separated water, in which methanol is separated from water, in order to recover methanol and / or water in a purity in which the substances are reused as make-up water or inhibitor can be.
• RU 2602908 therefore discloses a process for the deacidification of crude gas, in which a deacidified natural gas with a low MeOH content is obtained.
• the raw gas containing MeOH is first introduced into an absorber.
• the MeOH-containing crude gas is brought into contact with an aqueous amine solution in the absorber.
• acidic gases such as CO2
• most of the MeOH is also absorbed.
• the loaded amine solution is regenerated at a higher temperature in a regenerator, the acid gases and MeOH being stripped out of the loaded amine solution.
• the stream obtained via the top of the regenerator is fed to a condenser in which the predominant portion of methanol is condensed out together with the stripping steam and separated from the acid gases remaining in the gas phase.
• RU 2602908 discloses further processing of the MeOH-containing condensate from the regenerator in a downstream distillation column.
• the regenerator condensate is separated into methanol (top product) and water (bottom product).
• the MeOH can then be used again as an inhibitor in the raw gas.
• the almost MeOH-free water is fed into a buffer tank where it is mixed with the regenerated absorbent to compensate for water losses and returned to the absorber.
• a disadvantage of the process described in RU 2602908 is that the process described in RU 2602908 requires an additional distillation column. This increases the operating and / or investment costs. Similar problems can arise in the production of synthesis gas.
• methanol can be formed as a by-product by steam reforming methane.
• acidic gases such as CO 2 and CO
• methanol can also be present in the fluid stream.
• the deacidified synthesis gas and / or the deacidified hydrogen can also contain residual amounts of methanol.
• water which can generally be introduced by an aqueous absorbent, the problems described above can also arise during the subsequent drying of the synthesis gas and / or hydrogen.
• the object of the present invention was therefore to generate a deacidified fluid stream, in particular a deacidified natural gas, which has a low MeOH content, the manufacturing process required for this being intended to have lower investment and operating costs.
• the present invention should enable a high recovery rate of the methanol used as an inhibitor.
• the method according to the invention should enable the streams from certain process steps to be returned to other process steps.
• the object of the present invention has been achieved by a
• a process for producing a deacidified fluid stream from a fluid stream containing methanol and at least one acidic gas comprising a) an absorption step in which the fluid stream is brought into contact with an absorbent in an absorber, one containing methanol and acid Absorbent laden gases and an at least partially deacidified fluid stream; b) a regeneration step in which at least a portion of the loaded absorbent obtained from step a) is regenerated in a regenerator, an at least partially regenerated absorbent and a gaseous stream containing methanol and at least one acidic gas being obtained; c) a recycling step in which at least a partial stream of the regenerated absorbent from step b) is returned to absorption step a), d) a condensation step in which a condensate containing methanol is condensed out of the gaseous stream from step b) ; characterized in that the regenerator additionally comprises a backwashing section and the condensate from step d) is partially returned to the upper
• a fluid stream containing methanol and at least one acidic gas is used in the process according to the invention.
• the amount of methanol in the fluid stream is preferably in the range from 50 to 5000 vppm, particularly preferably 100 to 1000 vppm and very particularly preferably 200 to 800 vppm.
• methanol is preferably added to the fluid stream before step a).
• methanol can also be formed as a by-product in the production of the fluid stream, for example in the steam reforming of methane.
• the fluid stream used contains at least one acidic gas.
• the crude gas preferably contains CO 2 and / or H 2 S.
• CO 2 and / or H 2 S other acidic gases can be used in the
• Raw gas may be present, such as COS and Mercaptane.
• SO 3 , SO 2 , CS 2 and HCN may also be present.
• the content of acid gases in the fluid stream is generally 0.01 to 40 vol.%, Preferably 0.05 to 15 vol.% And particularly preferably 0.1 to 5 vol.%.
• the fluid stream used in the method according to the invention contains hydrocarbons.
• the hydrocarbon content in the fluid stream is generally 60 to 99.9% by volume, preferably 85 to 99.5% by volume and particularly preferably 95 to 99% by volume.
• the hydrocarbons contained in the fluid stream preferably contain 80 to 100% by volume of methane, particularly preferably 90 to 99.9% by volume and very particularly preferably 95 to 99% by volume of methane.
• the fluid stream used in the method according to the invention can contain water.
• the water content in the fluid stream is generally in a range from> 0% by volume up to a content which corresponds to the saturation concentration of water in the fluid stream under the prevailing pressure and temperature conditions.
• the fluid stream can contain other components such as other gases (N2 or He), mercury or naturally occurring radioactive substances.
• the proportion of further components in the fluid stream is generally 0 to 4% by volume, preferably 0.0001 to 3.5% by volume and very particularly preferably 0.0005 to 1.5% by volume.
• the fluid stream can be any fluid stream that contains at least one acidic gas and methanol.
• the fluid stream is preferably raw gas.
• the fluid stream can also be a synthesis gas or a biogas to which methanol has been added or in the production of which methanol is formed as a by-product.
• a raw gas from which natural gas condensate and water have been separated by condensation is generally used as the raw gas.
• the natural gas condensate and water can be separated off according to a process known to the person skilled in the art, for example by lowering the temperature of the raw gas conveyed and separating the condensed components, such as water and the natural gas condensate, from the uncondensed components of the raw gas.
• a fluid flow is preferably used which has a total pressure in the range from 20 to 120 bar, particularly preferably 40 to 100 bar and very particularly preferably 50 to 80 bar.
• the fluid stream is introduced into an absorption step in which the fluid stream is brought into contact with an absorbent in an absorber, an absorbent loaded with methanol and acid gases and an at least partially deacidified fluid stream being obtained.
• the absorbent contains at least one amine.
• Preferred amines are the following: i) Amines of the formula I:
• NR 1 (R 2 ) 2 (I) wherein R 1 under C2-C6-H yd roxyalkyl groups, Ci-C6-alkoxy-C2-C6-alkyl groups, hydroxy-C1-C6-alkoxy-C2-C6-alkyl groups and 1 -Piperazinyl-C 2 -C 6 -alkyl groups and R 2 is independently selected from H, Ci-C 6 -alkyl groups and C2-C6-H yd roxyalkyl groups; ü) Amines of the formula II:
• R 3 R 4 NX-NR 5 R 6 (II) wherein R 3 , R 4 , R 5 and R 6 independently of one another under H, Ci-C 6 alkyl groups, C2-C6-hydroxyoxyalkyl groups, Ci-C6-alkoxy-C2-C6-alkyl groups and C2-C6- Aminoalkyl groups are selected and X is a C2-C6-alkylene group, -X 1 -NR 7 -X 2 - or -X 1 -0-X 2_ , where X 1 and X 2 independently of one another are C2-C6-alkylene groups and R 7 represents H, a C1-C6 alkyl group, C2-C6 hydroxyalkyl group or C2-C6 aminoalkyl group; iii) 5- to 7-membered saturated heterocycles with at least one nitrogen atom in the ring, which may contain one or two further heteroatoms selected from nitrogen and oxygen in the ring, and iv) mixtures thereof.
• amines are: i) 2-aminoethanol (monoethanolamine), 2- (methylamino) ethanol, 2- (ethylamino) ethanol, 2- (n-butylamino) ethanol, 2-amino-2-methylpropanol, N - (2-aminoethyl) piperazine, methyl diethanolamine, ethyl diethanolamine, dimethylaminopropanol, t-butylaminoethoxyethanol (TBAEE), 2-amino-2-methylpropanol, diisoproanolamine (DI PA); ii) 3-methylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, 2,2-dimethyl-1,3-diaminopropane, hexamethylenediamine, 1,4-diaminobutane, 3,3-iminobispropylamine, tris (2-aminoethyl) amine, bis ( 3-
• the absorbent contains at least one of the amines monoethanolamine (MEA), methylaminopropylamine (MAPA), piperazine (PIP), diethanolamine (DEA), triethanolamine (TEA), diethylethanolamine (DEEA), diisopropanolamine (DIPA), aminoethoxyethanol ( AEE), tert-butylaminoethoxyethanol (TBAEE dimethylaminopropanol (Dl MAP) and methyldiethanolamine (MDEA) or mixtures thereof.
• MEA monoethanolamine
• MDEA methylaminopropylamine
• PIP piperazine
• DEA diethanolamine
• TAA diethylethanolamine
• DIPA diisopropanolamine
• AEE aminoethoxyethanol
• TSAEE tert-butylaminoethoxyethanol
• TSAEE dimethylaminopropanol
• MDEA methyldiethanolamine
• the amine is a hindered amine or a tertiary amine.
• a sterically hindered amine is a secondary amine in which the amine nitrogen is bonded to at least one secondary carbon atom and / or at least one tertiary carbon atom; or a primary amine in which the amine nitrogen is attached to a tertiary carbon atom.
• a preferred sterically hindered amine is t-butylaminoethoxyethanol.
• a preferred tertiary amine is methyl diethanolamine.
• the absorbent preferably also contains an activator if the amine contained in the absorbent is a sterically hindered amine or a tertiary amine.
• the activator is generally a sterically unhindered primary or secondary amine. In these sterically unhindered amines, the amine nitrogen of at least one amino group is only bound to primary carbon atoms and hydrogen atoms. If the aim is only to remove part of the gases contained in the fluid stream, for example the selective removal of H2S from a fluid stream containing H2S and CO2, the absorbent preferably contains no activator.
• the sterically unhindered primary or secondary amine which can be used as an activator is selected, for example, from alkanolamines, such as monoethanolamine (MEA), diethanolamine, (DEA), ethylaminoethanol, 1-amino-2-methyl-propan-2-ol, 2 -Amino-1-butanol, 2- (2-aminoethoxy) ethanol and 2- (2-aminoethoxy) ethanamine, polyamines such as hexamethylene diamine, 1,4-diaminobutane, 1,3-diaminopropane, 3- (methylamino) propylamine (MAPA ), N- (2-hydroxyethyl) ethylenediamine, 3- (dimethylamino) propylamine (DMAPA), 3- (diethylamino) propylamine, N, N'-bis (2-hydroxyethyl) ethylenediamine, 5-, 6- or 7 -linked saturated heterocycles with at least one NH
• Piperazine is very particularly preferred.
• the absorbent contains the tertiary amine methyldiethanolamine and the activator piperazine.
• the molar ratio of activator to sterically hindered amine or tertiary amine is preferably in the range from 0.05 to 1.0, particularly preferably in the range from 0.05 to 0.7.
• the absorbent contains 10 to 60% by weight of amine.
• the absorbent can additionally contain physical solvents. Suitable physical solvents are, for example, N-methylpyrrolidone, tetramethylene sulfone, oligoethylene glycol dialkyl ethers such as oligoethylene glycol methyl isopropyl ether (SEPASOLV MPE), oligoethylene glycol dimethyl ether (SELEXOL).
• the physical solvent is generally present in the absorption medium in amounts of 1 to 60% by weight, preferably 10 to 50% by weight, in particular 20 to 40% by weight.
• the absorbent contains less than 10% by weight, e.g. less than 5% by weight, especially less than 2% by weight of inorganic basic salts, such as e.g. Potassium carbonate.
• the absorbent can also contain additives such as corrosion inhibitors, antioxidants, enzymes, antifoams, etc.
• additives such as corrosion inhibitors, antioxidants, enzymes, antifoams, etc.
• the amount of such additives is in the range of about 0.01-3% by weight of the absorbent.
• Fresh absorbent can be fed to the absorber, or regenerated absorbent can be fed to the absorber in the return step e).
• the addition of fresh absorbent means that the components of the absorbent have not yet gone through steps b) to e).
• the supply of regenerated absorbent requires that at least some of the components of the absorbent have gone through steps b) to e).
• the absorbent preferably contains 0.05% by volume or less methanol, particularly preferably 0.03% by volume or less methanol, very particularly preferably 0.01% by volume or less methanol and in particular 0.005% by volume or less methanol.
• the absorbent is preferably aqueous. That that the various constituents of the absorbent, such as amine, methanol, physical solvents, additives, are mixed with water in the abovementioned quantities.
• An aqueous solution of methyldiethanolamine is very particularly preferably used as the absorbent.
• the fluid stream is brought into contact with the absorbent in step a) in an absorber.
• the absorber is preferably an absorption tower or an absorption column, e.g. B. a packed body, packing or tray column.
• the absorber generally comprises an absorption zone and optionally a backwash zone.
• Absorption Zone :
• the absorption zone is considered to be the section of the absorption column in which the fluid stream comes into material exchange contact with the absorption medium.
• the fluid stream is brought into contact with the absorbent in the absorption zone, preferably in countercurrent.
• the absorption zone usually contains internals, e.g. Packings, packages and / or trays, such as valve, bell, Thormann or sieve trays.
• the height of the packing elements / packings of the absorption zone is preferably in the range from 5 to 20 m, particularly preferably in the range from 6 to 15 m and very particularly preferably in the range from 8 to 14 m.
• the number of trays in the absorption zone is preferably in the range from 8 to 30, particularly preferably 12 to 25 and very particularly preferably 15 to 23 trays.
• the absorption zone can be subdivided into one or more sections, preferably 2 to 4 sections.
• Support and holding trays and / or distributor trays can be arranged between the individual sections of the absorption zone, which improve the distribution of the absorbent over the entire column cross section.
• the temperature of the absorbent introduced into the absorption zone is in
• the pressure in the absorber is usually in the range from 30 to 120 bar, particularly preferably 40 to 100 bar and very particularly preferably 50 to 80 bar.
• the inlet point for the introduced fluid flow is preferably below or in the lower area of the absorption zone.
• the feed is preferably via a gas distributor.
• the absorber can comprise one or more feed points for the absorber introduced.
• the absorber can thus comprise an inlet for fresh absorbent and an inlet for regenerated absorbent. Fresh and regenerated absorbent can also be fed into the absorber together via an inlet point.
• the one or more feed points are preferably located above or in the upper area of the absorption zone. Individual constituents of the absorption medium, such as make-up water, can also be supplied via the inlet point for fresh absorption medium. If the absorber has an optional backwash zone, the feed preferably takes place between the absorber zone and the backwash zone.
• a demister can be attached in the area of the draw-off point in order to separate any liquid residues of the absorbent or the detergent from the emerging fluid flow.
• the at least partially deacidified fluid stream can optionally be brought into contact with a washing liquid in the absorption zone.
• the feed point for the detergent is preferably in the upper region or above the absorption zone.
• the washing liquid is particularly preferably an aqueous liquid.
• the washing liquid can be an intrinsic liquid to the process, i.e. an aqueous liquid that occurs elsewhere in the process, or around aqueous liquids supplied from outside.
• the washing liquid preferably comprises a condensate (so-called absorber head condensate) and / or fresh water formed when the deacidified fluid stream is cooled downstream.
• entrained absorption agent components such as amines
• the water balance of the process can also be balanced if more water is discharged via the escaping streams than is entered via the entering streams.
• the absorber can have a so-called backwash zone.
• the deacidified fluid flow is counter-flowed with a washing liquid.
• the backwash zone is usually a section of the absorber, which is located above the feed point of the absorbent.
• the backwashing zone preferably has packing elements, packings and / or bottoms in order to intensify the contact of the fluid stream with the washing liquid.
• the backwash zone has floors, in particular valve, bell, Thormann or sieve floors.
• the backwash zone preferably comprises 1 to 7, particularly preferably 2 to 6, and very particularly preferably 3 to 5 trays, or a packing height (packing / packs) of preferably
• the washing liquid is generally introduced above the backwash zone or in the upper region of the backwash zone.
• the washing liquids mentioned above can be used as the washing liquid.
• the washing liquid can be recycled via the backwashing zone.
• the washing liquid is below the backwash zone, for. B. collected by means of a suitable collecting base and pumped to the upper end of the backwashing zone by means of a pump.
• the recycled washing liquid can be cooled, preferably to a temperature of 20 to 70 ° C., in particular 30 to 60 ° C.
• the washing liquid is expediently pumped over a cooler.
• a partial stream of the washing liquid is preferably discharged from the backwashing zone.
• the deacidified fluid stream is preferably drawn off via a discharge in the upper part of the absorber.
• the deacidified fluid stream can be passed through a condenser.
• condensers with a cooling coil or spiral tube, plate heat exchanger, double tube cooler and tube bundle heat exchanger can be used as the condenser.
• the capacitor is generally operated at a temperature in the range from 10 to 60 ° C., preferably 20 to 50 ° C., particularly preferably 20 to 30 ° C.
• the deacidified fluid stream obtained in step a) preferably contains 0.01 to 10 vppm methanol, particularly preferably 0.05 to 5 vppm methanol, and very particularly preferably 0.1 to 3 vppm methanol.
• the water content of the deacidified fluid stream is generally 80-100% of the saturation concentration of water in the fluid stream under the present pressure and temperature conditions.
• the content of H2S in the deacidified fluid stream is preferably 5 vppm or less and the CO 2 content
• the CO 2 content in the deacidified fluid stream is preferably 100 vppm and less and particularly preferably 50 vppm and less.
• the FhS content in the deacidified fluid stream is preferably 5 vppm and less and particularly preferably 2 vppm and less for LNG.
• step a) One or more of the following work-up steps are then optionally carried out on the deacidified fluid stream obtained in step a): aa) water removal; bb) removal of mercury; cc) removal of nitrogen; dd) removal of natural gas condensates; and / or ee) liquefaction (LNG)
• the water removal aa) is preferably carried out as pressure swing adsorption (or pressure swing adsorption (PSA)) and particularly preferably as temperature swing adsorption (or temperature swing adsorption (TSA)) or as glycol drying.
• PSA pressure swing adsorption
• TSA temperature swing adsorption
• the PSA or TSA can be used according to methods known to those skilled in the art. Common implementation variants are, for example, in Nag, Ashis, “Distillation and Hydrocarbon Processing Practices”, PennWell 2016, ISBN 978-1-59370-343-1 or in A. Terrigeol, GPA Europe, Annual Conference, Berlin, Germany, 23rd-25th May, 2012 (https: //www.cecachemicals.com/export/sites/ceca/.content/medias/downloads/products/dtm/molecular-sieves-contaminants-effects-consequences-and- mitigation.pdf).
• a zeolite, activated carbon or molecular sieve is preferably used in the PSA or TSA.
• a molecular sieve is preferably used as the solid adsorbent in the PSA or TSA.
• a liquid absorbent such as monoethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG) or tetraethylene glycol (TREG), is preferably used in the glycol drying.
• TEG is particularly preferably used as a liquid absorbent.
• glycol drying can be carried out according to process variants known to the person skilled in the art. Examples of glycol drying can also be found, for example, in Nag, Ashi's “” Distillation and Hydrocarbon Processing Practices ", PennWell 2016, ISBN 978-1-59370- 343-1. After drying aa), additional processing steps such as bb) mercury removal, cc) nitrogen removal, dd) removal of natural gas condensates and ee) liquefaction of natural gas to LNG can optionally be carried out. Details of the process steps mentioned can also be found in Nag, Ashi's “Hydrocarbon Processing Practices”.
• the one or more purification steps aa) to dd) generally result in a fluid flow that meets the specifications of end customers and / or sales companies and can be sold as so-called sales gas in the case of natural gas or in a further liquefaction step ee) can be liquefied to LNG.
• step a) an absorbent loaded with acid gases is also obtained.
• a relaxation step is first carried out on the loaded absorbent before it is introduced into the regeneration step b).
• the loaded adsorbent is generally passed into an expansion tank.
• the loaded adsorbent removed from the bottom of the absorber is generally expanded via a throttle valve.
• the loaded adsorbent is preferably expanded to a pressure of 3 to 15 bar, preferably 4 to 12 and particularly preferably 5 to 10 bar.
• the relaxation usually leads to the desorption of co-absorbed hydrocarbons that pass into the gas phase (so-called flash gas).
• flash gas can be returned to absorption by means of a compressor or burned or flared on site as energy.
• the expansion tank is usually a tank that is free of special fittings.
• the flash tank is preferably a so-called flash drum.
• the expansion tank In the upper area of the expansion tank there is usually a gas outlet for the gases that have been converted into the gas phase.
• a demister can in turn preferably be arranged in the area of the gas outlet. If necessary, the acid gases contained can be separated from the flash gas in a further absorption column. Typically, a partial stream of the regenerated solvent is fed to the additional absorption column.
• the absorbent which has at least partially been loaded with the acid gases and which has not been converted into the gas phase is generally drawn off and is generally passed into step b).
• the adsorbent loaded at least partially with acid gases is passed into regeneration step b).
• the regeneration step at least a part of the loaded absorbent obtained from step a) is regenerated in a regenerator, an at least partially regenerated absorbent and a gaseous stream containing methanol and at least one acidic gas being obtained.
• the fluid stream can contain residual amounts of water that have not been separated in the rewax zone.
• the adsorbent which is at least partially loaded with acid gases, is preferably passed over a heat exchanger.
• the absorption medium which is at least partially loaded with acid gases, is preferably heated to a temperature in the range from 50 to 150 ° C., particularly preferably 70 to 130 ° C. and very particularly preferably 80 to 110 ° C.
• the regenerated absorbent drawn off from the bottom of the regenerator is used as the heating medium in the heat exchanger.
• This embodiment has the advantage that the thermal energy of the regenerated absorbent from stage b) can be used to heat the loaded absorbent. This can further reduce the energy costs of the overall process.
• the regenerator is usually designed as a strip column.
• the regenerator preferably comprises a regeneration zone and an evaporator.
• the regenerator is preferably operated at a head pressure in the range from 1 to 5 bar, preferably 1.2 to 4 and particularly preferably 1.3 to 2.5 bar.
• a liquid drain for the regenerated solvent is generally arranged in the sump of the regenerator. There is usually a gas outlet for the gaseous stream at the top of the regenerator. A demister is preferably attached in the area of the gas outlet.
• the gaseous stream is passed into a condensation step d), as described below.
• the regenerator generally has a regeneration zone arranged above the sump and below the backwash zone.
• the region of the regenerator with which the loaded absorbent comes into contact with the steam generated by the bottom evaporator is regarded as the regeneration zone.
• the regeneration zone usually contains internals, e.g. Packings, packings and / or trays, such as valve, bell, Thormann or sieve trays.
• the height of the packing / packing in the regeneration zone is preferably in the range from 5 to 15 m, particularly preferably in the range from 6 to 12 m and very particularly preferably in the range from 8 to 12 m.
• the number of soils in the regeneration zone is preferably in the range from 10 to 30, particularly preferably 15 to 25 and very particularly preferably 17 to 23 soils.
• the regeneration zone can in turn be divided into several sections, preferably 2 to 4.
• Support and holder trays and / or distributor trays can be arranged between the sections of the regeneration zone, which improve the distribution of liquid over the entire cross section of the regenerator.
• the loaded absorbent is preferably introduced into the regenerator in the upper region or above the regeneration zone and below the backwash zone.
• the absorbent flowing down through the regeneration zone is generally countered in the regeneration zone by the steam generated in the evaporator.
• the zone of the regenerator below the regeneration zone is generally referred to as the sump.
• the regenerated absorbent is usually collected and fed to the evaporator via a liquid discharge in the lower area of the regenerator via pipelines and / or partially returned to the absorber as a regenerated absorbent.
• the sump can be divided by a collecting base, which is arranged between the sump fume cupboard and the feed point for the steam generated in the evaporator.
• At least part of the regenerated absorbent is passed from the bottom draw of the regenerator into an evaporator.
• the bottom draw from the regenerator is preferably passed completely into the evaporator.
• the evaporator is usually a reboiler (boiler evaporator), natural circulation evaporator (thermosiphon) or forced circulation evaporator.
• the evaporator of the regenerator is preferably arranged outside the regenerator and connected to the sump vent via pipes.
• the evaporator is generally operated at temperatures in the range from 100 to 150 ° C., preferably 105 to 140 ° C. and very particularly preferably 1 10 to 130 ° C.
• the bottom draw is evaporated in the evaporator and returned to the regenerator.
• the steam and non-evaporated liquid are preferably fed in below the regeneration zone, preferably into the bottom of the regenerator.
• the steam generated is preferably fed in below the collecting tray.
• the regenerator has a backwash zone above the regeneration zone, in particular preferably above the feed point for the loaded absorbent.
• the backwash zone is generally designed as a section of the regenerator arranged above the regeneration zone.
• the backwashing zone preferably has internals, in particular fillers, packings and / or the bottoms, in order to intensify the contact of the fluid stream with the washing liquid.
• the washing section particularly preferably has bottoms, in particular valve bottoms or bell bottoms.
• the internals are fillers and / or packings.
• the pack height (packing / packs) is preferably in a range from 1 to 10, particularly preferably 2 to 8 and very particularly preferably 3 to 6 m.
• the backwash zone has trays, in particular valve trays or bubble trays, the number of trays preferably being in the range from 3 to 20, particularly preferably 4 to 16 and, very particularly preferably 6 to 12 trays.
• a washing liquid can be introduced into the upper region of the backwashing zone or above the backwashing zone.
• An aqueous or a slightly acidic, aqueous solution, in particular water, is generally used as the washing liquid.
• the temperature of the washing liquid is generally in the range from 10 to 60 ° C., preferably in the range from 20 to 55 ° C. and particularly preferably 30 to 40 ° C.
• the backwash zone thus enables methanol to be enriched in the gaseous stream, so that it does not have to be separated in a subsequent column, but a subsequent condensation step is sufficient to obtain methanol in a purity which enables it to be used again as an inhibitor.
• the regenerated absorbent obtained at the bottom of the regenerator from step b) is returned to the absorption step a).
• the regenerated absorbent is returned, as described above, in one of the inlet points of the absorber for the regenerated absorbent.
• the gaseous stream from the regenerator is introduced into a condensation step d).
• a condensate containing methanol is condensed out of the gaseous stream from step b) (condensate drain).
• the condensate can also contain water that was not separated in the backwashing section.
• the uncondensed gas phase is preferably discharged from the process as waste gas (waste gas).
• the condensation step is preferably carried out in such a way that the gaseous stream from stage b) is passed over one or more condensers (regenerator top condensers).
• the top condensers usually include a heat exchanger and a container in which the liquid phase can be separated from the gas phase (phase separation container).
• the heat exchanger and container can also be integrated in one component.
• the regenerator top condenser is generally operated in such a way that methanol and any water present condenses, while the acidic gases predominantly remain in the gas phase.
• Capacitors with a cooling coil or a spiral tube, a double tube cooler and a tube bundle heat exchanger can be used as the regenerator top condenser, for example.
• the regenerator top condenser is generally operated at a temperature in the range from 10 to 60 ° C., preferably 20 to 55 ° C., particularly preferably 30 to 40 ° C.
• the gaseous stream from stage b) is passed through a regenerator top condenser.
• the gaseous stream from stage b) is passed over two regenerator top condensers.
• the first two regenerator head condensers are preferably cooled with air or cooling water and the second two regenerator head condensers are cooled with a coolant.
• the first regenerator top condenser is generally operated at a temperature in the range from 20 to 60 ° C. and preferably 25 to 45 ° C.
• the second regenerator top condenser is generally operated with a coolant at a temperature in the range from 3 to 20 ° C., preferably 5 to 15 ° C., particularly preferably 5 to 10 ° C.
• the embodiment with at least two overhead condensers has the advantage that the overhead condensate from the second overhead generator has a higher methanol content and can therefore generally be reused as an inhibitor in the raw gas without additional work-up.
• This embodiment with at least two overhead condensers has the further advantage that the content of methanol in the acidic exhaust gas can be reduced, since more methanol can be condensed out at lower temperatures. As a result, the methanol recovery rate can be increased, for example to more than 80%, based on the methanol introduced into the process.
• part of the condensate from the condensation step d) is returned to the regeneration step b).
• a part of the condensate from the condensation step d) is removed from the process and represents the recovered methanol.
• the reflux ratio with respect to the condensate flow is preferably in the range from 5 to 100, particularly preferably in the range from 10 to 70, very particularly preferably in the range from 12 to 40 and particularly preferably in the range from 15 to 38.
• the condensate from the condensation step d) is introduced in the upper region or above the backwashing zone of the regenerator in step b).
• a washing liquid as described above, can additionally be introduced into the regenerator together with the condensate from stage d).
• the introduction can take place via the same inlet point.
• Detergent can also be introduced via a separate feed point.
• FIG. 1 and 3 illustrate an embodiment in which the regenerator comprises a top capacitor.
• FIG. 2 and FIG. 4 represent a preferred embodiment in which the regenerator additionally comprises two head capacitors.
• the absorber is designed as an absorption column.
• the absorption column preferably has an absorption zone.
• the section of an absorption column in which the fluid stream comes into material exchange contact with the absorption medium is regarded as the absorption zone.
• the absorption zone preferably contains internals, e.g. Packings, packs and / or bottoms.
• the absorption zone is preferably divided into two to four packing sections arranged one above the other, which are separated from one another by support and holding trays and / or a distribution tray.
• the height of the packing / packing in the absorption zone is preferably in the range from 5 to 20 m, particularly preferably in the range from 6 to 15 m and very particularly preferably in the range from 8 to 14 m.
• the number of trays in the absorption zone is preferably in the range from 8 to 30, particularly preferably 12 to 25 and very particularly preferably 15 to 23 trays.
• An inlet for the fluid stream to be deacidified is located below or in the lower region of the absorption zone.
• Fresh absorbent can be supplied via an inlet in the upper area or above the absorption zone.
• the supply of fresh absorbent can also include the supply of individual constituents of the absorbent, such as make-up water.
• Regenerated absorbent can be supplied via the same feed point or a separate feed point, which is also located in the upper area or above the absorption zone.
• the absorption zone preferably at the top of the absorption column, there is preferably a withdrawal point for the deacidified fluid stream.
• a demister is preferably installed in the area of the extraction point for the deacidified fluid stream.
• the absorber comprises an additional backwash zone above the absorption zone.
• the backwash zone is generally designed as a section of the absorber designed as a reinforcing part, which is arranged above the inlet point for the absorption medium.
• the backwash zone preferably has packing elements, packings and / or bottoms in order to intensify the contact of the fluid flow with the washing liquid.
• the backwash zone has floors, in particular valve, bell, Thormann or sieve floors.
• a feed point for detergent is preferably located above the backwash zone.
• the backwash zone preferably comprises 1 to 7, particularly preferably 2 to 6, and very particularly preferably 3 to 5 trays, or a packing height (packing or packing) of preferably 1 to 6 m, particularly preferably 2 to 5 and very particularly preferably 2 to 3 m.
• a collecting base can be arranged below the backwashing zone, on which washing liquid can be collected and recycled.
• the recycling is usually carried out by a pump that pumps the washing liquid from the collecting tray to the feed point.
• the washing liquid can be cooled using a heat exchanger.
• the heat exchanger can be designed as a plate heat exchanger or a tube bundle heat exchanger.
• the bottom stream from the regenerator b) is preferably used as the heating medium of the heat exchanger.
• the regenerator in FIGS. 1 to 4 also comprises a regeneration zone, an evaporator, an inlet for the loaded absorption medium, a liquid discharge in the sump of the regenerator, a backwash zone and a discharge point (gas discharge) in the top region of the regenerator.
• the region of the regenerator with which the loaded absorbent comes into contact with the steam generated by the bottom evaporator is regarded as the regeneration zone.
• the regeneration zone contains internals, e.g. Packings, packs and / or bottoms.
• the regeneration zone is preferably divided into two to four packing sections arranged one above the other, which are separated from one another by support and holding trays and / or a distribution tray.
• the height of the packings / packs in the regeneration zone is preferably in the range from 5 to 15 m, particularly preferably in the range from 6 to 12 m and very particularly preferably in the range from 8 to 12 m.
• the number of soils in the regeneration zone is preferably in the range from 10 to 30, particularly preferably 15 to 25 and very particularly preferably 17 to 23 soils
• the inlet for the loaded absorbent is usually located above or in the upper region of the regeneration zone.
• the regenerator in Figures 1 to 4 also includes an evaporator.
• the evaporator is preferably a reboiler, natural circulation evaporator or forced circulation evaporator.
• the evaporator is preferably connected to a liquid outlet at the bottom of the regenerator via a pipe.
• the area below the regeneration zone is generally referred to as the sump.
• the vapor-liquid mixture generated in the evaporator is preferably introduced above the liquid outlet at the bottom, but below the regeneration zone into the lower region of the regenerator via an inlet point.
• the bottom of the regenerator is divided by a collecting base.
• the absorbent collected there is fed to the heat exchanger.
• the steam is fed in and the liquid is returned below the collecting tray.
• the regenerator in FIGS. 1 to 4 also includes a withdrawal point for the gaseous stream formed during the regeneration.
• the withdrawal point for the gaseous stream formed during the regeneration is preferably arranged in the top region of the regenerator.
• a demister is preferably located in the area of the withdrawal point.
• the regenerator in FIGS. 1 to 4 further comprises a backwash zone which has built-in elements.
• the backwashing zone contains packings or packing elements as internals, the packing height (packs / packing elements) preferably in the range from 1 to 10 m, particularly preferably 2 to 8 and very particularly preferably in the range from 3 to 6 m lies.
• the backwash zone contains floors as internals.
• the number of trays is preferably in the range from 3 to 20, particularly preferably 4 to 16 and, very particularly preferably 6 to 12.
• the trays of the washing section can be, for example, valve trays, bell trays, Thormann trays or sieve trays.
• the top condenser comprises a heat exchanger, a container for phase separation (phase separation vessel), a gas outlet and a condensate drain.
• condensers for example, condensers with a cooling coil or a spiral tube, a double tube cooler and a tube bundle heat exchanger can be used.
• FIGS. 2 and 4 A preferred embodiment is shown in FIGS. 2 and 4, which comprises two condensers, each with a heat exchanger, phase separation vessel, gas vent and a condensate drain.
• the first condenser is preferably cooled with air or cooling water and the second condenser is preferably cooled with a coolant.
• the regenerator also has an inlet in the upper area or above the backwash zone, which is connected to a condensate drain from a top condenser d)
• the preferred device also includes a flash tank.
• the expansion tank is connected to the absorber a) and the regenerator b).
• the liquid discharge from the sump of the absorber is preferably connected to the relaxation tank via a valve.
• the expansion tank At least some of the acid gases of the loaded absorption medium are converted into the gas phase and separated from the non-evaporated liquid phase.
• the gas phase is usually drawn off in the upper area of the flash tank as acid exhaust gas and discharged from the process.
• the flash tank In the lower area of the flash tank there is preferably a liquid drain for the non-evaporated liquid phase, which is connected to the regenerator via a pipeline.
• the feed point for the liquid phase from the expansion tank is preferably located above the regeneration zone.
• a heat exchanger is particularly preferably arranged between the expansion tank and the regenerator and is operated with the bottom discharge of the regenerator as a heating medium.
• the device according to the invention, its use according to the invention and the method according to the invention has the advantage over the methods known from the prior art in which the condensation from the condensation step d) is subjected to a further distillation that a distillation column can be saved ,
• the process according to the invention also has the advantage that the methanol supplied as an inhibitor can be recovered at a high rate, preferably more than 80%, based on the methanol supplied. This further reduces the operating costs of the overall process.
• the regenerated absorbent thus has such a low methanol content that the methanol which is introduced in step a) with the fluid stream to be deacidified can be removed almost completely. In this way, recycle streams can be used optimally and the supply of constituents of the absorbent to compensate for losses can be reduced.
• the removal of the methanol from the deacidified fluid stream has the advantage that the problems which occur in the presence of methanol can be reduced in subsequent work-up steps.
• the subsequent dewatering is designed, for example, as PSA or TSA, in which a molecular sieve is used as the solid drying agent, a 3 A molecular sieve can be used instead of a 4 A molecular sieve, since the adsorption of water does not compete with the adsorption of methanol. This means that no other components such as FhS and ethane are absorbed. This enables a smaller design of the drainage level. When the molecular sieve is regenerated by increasing the temperature, a low methanol content leads to less coking of the molecular sieve.
• TEG triethylene glycol
• Nm3 / h stands for the volume flow given in standard cubic meters per hour.
• the standard cubic meter is based on a temperature of 273.15 K and a pressure of 1.01325 bar. All data in the unit “Vol .-%” also refer to these conditions.
• an aqueous amine solution consisting of piperazine and methyldiethanolamine with a total amine content of 40% by weight is used as the absorbent.
• Feed gas 0.2 vol% CO2, 520 vppm methanol, rest hydrocarbons (CH 4 , C2H6) at a temperature of 26 ° C and a pressure of 63.5 bar.
• Absorbent An amine solution consisting of piperazine and methyldiethanolamine with a total amine content of 40% by weight. 0.1 m3 / h regenerated absorbent is used per 1000 Nm3 / hr feed gas. The regenerated absorbent has a temperature of 35 ° C.
• the built-in absorption column has packing elements with a total bed height of 14 m.
• the methanol content of the deacidified fluid stream (natural gas) obtained at the top of the absorber should not exceed 1 vppm.
• the methanol recovered at the top of the methanol distillation should have a purity of greater than 96 wt%.
• a process is simulated in a system according to FIG. 2 (two capacitors).
• the process consists of an absorption column, an expansion tank (HP flash), regenerator with evaporator and two overhead condensers.
• the liquid streams (methanol + water) condensed out in the top condenser are brought together and fed to the backwashing section with a reflux ratio of 29 or separated from the process as methanol
• the methanol recovery is 85% based on the amount of fluid present in stage a).

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• 2019
  • 2019-05-31 CA CA3102880A patent/CA3102880A1/en active Pending
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