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
  • B01D53/1493—Selection of liquid materials for use as 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
• • 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
• • 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
  • B01D53/18—Absorbing units; Liquid distributors therefor
• • 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
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/46—Removing components of defined structure
  • B01D53/62—Carbon oxides
• • 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
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
  • B01D53/77—Liquid phase processes
  • B01D53/78—Liquid phase processes with gas-liquid contact
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
  • C08G65/04—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers only
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
  • C08G65/04—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers only
  • C08G65/06—Cyclic ethers having no atoms other than carbon and hydrogen outside the ring
  • C08G65/08—Saturated oxiranes
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

• the present invention relates to an acid gas remover that removes acid gas, particularly carbon dioxide, from gas by a physical absorption method.
• the present invention is applied to the recovery of acid gases, especially carbon dioxide, from gases above atmospheric pressure.
• This gas is generally synthesis gas produced in the gasification of coal or the reforming of natural gas.
• Carbon dioxide constitutes a greenhouse gas that is believed to cause global warming. As seen with the effectuation of the Kyoto Protocol, both industry and society are demanding reductions in emissions of carbon dioxide into the atmosphere.
• the chemical absorption method is a method of absorbing and capturing carbon dioxide through a chemical reaction, and uses an acid gas remover under low pressure (normal pressure).
• the physical absorption method is a method of absorbing and capturing carbon dioxide under high pressure, using an acid gas remover under high pressure.
• a liquid capable of physically dissolving carbon dioxide is used as the acid gas remover used in the physical absorption method.
• Physical absorption is particularly suitable for high pressure processes because carbon dioxide becomes more soluble in liquids at higher partial pressures, increasing the absorption of carbon dioxide by liquids.
• Patent Document 1 describes the use of polyethylene glycol dimethyl ether.
• the present invention has been made in order to solve such problems.
• a method, an absorber with an acid gas remover and an acid gas scrubber are provided.
• the present invention provides the following [1] to [11].
• An acidic gas remover for removing carbon dioxide in gas which removes acidic gas containing at least one compound selected from a hydroxyl group-containing compound having a number average molecular weight of 500 or more and a derivative of the hydroxyl group-containing compound. agent.
• the acidic gas remover according to [1] or [2], wherein the hydroxyl group-containing compound is polyether monool, polyether polyol, polyester polyol, or polycarbonate diol.
• [7] A method for removing an acidic gas, comprising bringing the acidic gas removing agent according to any one of [1] to [6] into contact with the gas to remove carbon dioxide in the gas.
• the acidic gas removing method according to [7] wherein the acidic gas removing agent is brought into contact with the gas at a temperature within the range of 0 to 200°C.
• the acid-gas remover and the acid-gas removal method using the same are provided with a small fluctuation
• the acidic gas removing agent of the present invention is useful for removing carbon dioxide from gas containing a large amount of carbon dioxide and water vapor discharged from thermal power plants and the like.
• “Remove carbon dioxide in the gas” is not limited to the case where the carbon dioxide in the gas is removed and the carbon dioxide concentration in the gas becomes 0 vol%, but it means that the carbon dioxide concentration in the gas is reduced. means.
• "Hydroxy group-containing compound” is a general term for compounds having at least one hydroxyl group in one molecule.
• a “derivative of a hydroxyl group-containing compound” is obtained by esterification, etherification, amidation or urethanization of a part or all of the hydroxyl groups of a hydroxyl group-containing compound.
• a numerical range represented by "-” means a numerical range whose lower and upper limits are the numerical values before and after "-”.
• Partition coefficient (C(logP)) is the n-octanol/water partition coefficient, and is a parameter that indicates the hydrophilicity/hydrophobicity of a compound.
• ChemDraw Professional Ver. 17.1 Calculated value at 25°C by software package is used.
• it can be expressed as the sum of the products of the partition coefficients of each compound in the mixture and their mole fractions in the mixture.
• Viscosity is a value measured at 25° C. with an E-type viscometer in accordance with JIS K1557-5:2007.
• the number average molecular weight of the hydroxyl group-containing compound is the molecular weight in terms of hydroxyl value.
• the hydroxyl value equivalent molecular weight is calculated based on the hydroxyl value of the hydroxyl group-containing compound according to JIS K 1557-1: 2007, and is 56,100/(hydroxyl value of the hydroxyl group-containing compound) x (number of terminal groups of the hydroxyl group-containing compound). It is a molecular weight calculated by the formula.
• the number average molecular weight of a derivative of a hydroxyl group-containing compound is a molecular weight obtained by gel permeation chromatography (GPC) using polystyrene as a standard substance.
• the acid gas remover of the present invention is an acid gas remover for removing carbon dioxide in gas, and is one or more selected from hydroxyl group-containing compounds having a number average molecular weight of 500 or more and derivatives of the hydroxyl group-containing compounds. It is characterized by containing The acidic gas remover can reduce the variation in the amount of carbon dioxide absorbed even when water coexists in the gas.
• Examples of the hydroxyl group-containing compound having a number average molecular weight of 500 or more include polyether monool, polyether polyol, polyester polyol, polycarbonate diol, and polyether polycarbonate polyol.
• Polyether monools include, for example, polyoxyalkylene monools.
• polyether polyols include polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxytetramethylene glycol, and addition polymers of polyoxytetramethylene glycol and alkylene oxide.
• Polyester polyols include, for example, polyester polyols composed of condensates of dibasic acids and alcohols having two or more hydroxyl groups, and polycaprolactone polyols, which are ring-opening polymers of cyclic ester compounds.
• Polycarbonate diols include, for example, polycondensation products of alcohols having two hydroxyl groups and carbonate compounds, and reaction products of alcohols and cyclic esters having two hydroxyl groups and carbonate compounds.
• Polyether polycarbonate polyols include, for example, condensation polymerization products of polyether diols and carbonate compounds, reaction products of polyether polyols having 3 or more hydroxyl groups, alkylene oxides and carbon dioxide, addition of polycarbonate diols and alkylene oxides. A polymer is mentioned.
• hydroxyl group-containing compounds may be used singly or in combination of two or more.
• polyether monools, polyether polyols, polyester polyols, and polycarbonate diols are preferred from the viewpoint of availability, polyether monools, polyether polyols, and polycarbonate diols are more preferred, and polyether polyols are even more preferred.
• Polypropylene glycol is even more preferred.
• the polyether monool is preferably obtained by ring-opening addition polymerization reaction of a cyclic ether with an initiator having one active hydrogen atom in one molecule.
• the polyether polyol is preferably obtained by ring-opening addition polymerization reaction of a cyclic ether with an initiator having at least two active hydrogen atoms in one molecule.
• Initiators used in the production of polyether monools are compounds having one active hydrogen atom per molecule.
• a hydroxyl group is preferable as the group containing an active hydrogen atom.
• Specific examples of the initiator include monohydric alcohols such as methanol, ethanol, 2-propanol, n-butanol, isobutanol, 2-ethylhexanol, decyl alcohol, lauryl alcohol, tridecanol, cetyl alcohol, stearyl alcohol, and oleyl alcohol. are mentioned. The initiator may be used singly or in combination of two or more.
• Initiators used in the production of polyether polyols are compounds having at least two active hydrogen atoms in one molecule.
• a hydroxyl group is preferable as the group containing an active hydrogen atom.
• the initiator include water, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol and 1,6-hexanediol. , 1,4-cyclohexanediol, bisphenol A, bisphenol F, bisphenol S, resorcinol; Trihydric or higher alcohols such as sugar, methyl glucoside, trehalose, novolak, resol, and castor oil are included.
• the initiator may be used singly or in combination of two or more.
• an organic compound having 2 to 20 carbon atoms and having a cyclic ether structure is preferable.
• organic compounds having 2 to 20 carbon atoms and having a cyclic ether structure include ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, ⁇ -olefin oxides having 5 to 20 carbon atoms, and styrene oxide.
• cyclopentene oxide cyclohexene oxide, epichlorohydrin, glycidyl alkyl ether, glycidyl alkyl ester, and other epoxy group-containing compounds; oxetane, tetrahydrofuran.
• Ethylene oxide or propylene oxide is preferred, and propylene oxide is more preferred, as the cyclic ether used to produce the polyether monool or polyether polyol.
• Cyclic ethers used in the production of polyether monools or polyether polyols may be used singly or in combination of two or more.
• the ring-opening addition polymerization reaction of the cyclic ether is preferably carried out using a catalyst, and examples of the catalyst include a double metal cyanide complex catalyst; alkali catalysts such as sodium hydroxide, potassium hydroxide and cesium hydroxide; metal porphyrin catalyst as a complex obtained by reacting porphyrin; phosphazene catalyst; imino group-containing phosphazenium salt; tris(pentafluorophenyl) borane; Catalysts consisting of macrocyclic ligands of the type A catalyst may be used individually by 1 type, and may use 2 or more types together.
• the catalyst include a double metal cyanide complex catalyst; alkali catalysts such as sodium hydroxide, potassium hydroxide and cesium hydroxide; metal porphyrin catalyst as a complex obtained by reacting porphyrin; phosphazene catalyst; imino group-containing phosphazenium salt; tris(pentafluorophenyl
• the polyester polyol is preferably obtained by subjecting a dibasic acid component or a dialkyl ester of a dibasic acid component to an esterification reaction or a transesterification reaction with an alcohol.
• a known method can be applied to the esterification reaction or transesterification reaction for producing the polyester polyol.
• Dibasic acid components or dialkyl esters of dibasic acid components used in the production of polyester polyols include, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, brassyl Aliphatic dibasic acids such as acid and dimer acid, or dialkyl esters such as dimethyl ester, diethyl ester, dipropyl ester and dibutyl ester of these aliphatic dibasic acids; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid acids or dialkyl esters such as dimethyl ester, diethyl ester, dipropyl ester and dibutyl ester of these alicyclic dicarboxylic acids; aromatic dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid, or
• alcohols used for producing polyester polyols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, neopentyl glycol, 1,4-butanediol, and 1,6-hexanediol.
• diols such as; trihydric or higher alcohols such as glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol and sucrose.
• the esterification reaction or transesterification reaction for producing the polyester polyol is preferably carried out in the presence of a catalyst.
• catalysts include titanium compounds such as tetrabutyl titanate, tetraisopropyl titanate, tetra-2-ethylhexyl titanate, and titanium acetylacetonate; tin compounds such as dibutyltin oxide, methylphenyltin oxide, and hexaethyltin oxide; Magnesium compounds such as magnesium, magnesium oxide, and magnesium alkoxide are included. Among these, titanium compounds are preferable, and tetrabutyl titanate and titanium acetylacetonate are more preferable.
• a catalyst may be used individually by 1 type, and may use 2 or more types together.
• polycarbonate diols examples include polycondensates of alcohols and carbonate compounds, and reaction products of alcohols, cyclic esters, and carbonate compounds.
• Examples of alcohols used in the production of polycarbonate diols include diols.
• Specific examples of diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octane.
• Acyclic aliphatic diols without side chains such as diols, 1,18-octadecanediol, 1,20-eicosanediol; 2-methyl-1,8-octanediol, 2,2-dimethyl-1 ,3-propanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,4-butanediol, 2-methyl-1,3-propanediol, Acyclic aliphatic diols with side chains such as 3-methyl-1,
• Examples of carbonate compounds used for producing polycarbonate diols include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate, trimethylene carbonate, propylene carbonate, 1,2-butylene carbonate, and neopentylene.
• a carbonate is mentioned.
• dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate are preferred from the viewpoint of ease of reaction with alcohols and cyclic esters.
• a carbonate compound may be used individually by 1 type, and may use 2 or more types together.
• Cyclic esters used in the production of polycarbonate diols include, for example, ⁇ -caprolactone, ⁇ -propiolactone, ⁇ -methyl- ⁇ -propiolactone, ⁇ -valerolactone, glycolide, and lactide. Among these, ⁇ -caprolactone is preferred.
• a cyclic ester may be used individually by 1 type, and may use 2 or more types together.
• polycarbonate diol for example, JP-A-2012-77280, JP-A-2014-080590, JP-A-2015-91937, JP-A-2001-270938, JP-A-2010-126591, JP-A-2010-126591, It can be carried out by applying the methods described in Japanese Patent Application Laid-Open No. 02-289616, Japanese Patent Application Laid-Open No. 4-239023, and the like.
• the hydroxyl group-containing compound used in the acidic gas remover of the present invention has a number average molecular weight of 500 or more, preferably 500 to 30,000, more preferably 700 to 20,000, and more preferably 1,000 to 15,000. is particularly preferred.
• the number-average molecular weight is 500 or more, the distribution coefficient tends to be large, the separation from water is easy, the carbon dioxide absorption does not decrease even in the presence of water, and the carbon dioxide absorption ratio increases.
• Examples of the derivative of the hydroxyl group-containing compound having a number average molecular weight of 500 or more include derivatives of the hydroxyl group-containing compound.
• the derivative of the hydroxyl group-containing compound is obtained by esterification, etherification, amidation or urethanization of part or all of the hydroxyl groups of the hydroxyl group-containing compound.
• a method for esterifying, etherifying, amidating or urethanizing some or all of the hydroxyl groups of a hydroxyl group-containing compound a method used as a general esterification reaction, etherification reaction, amidation reaction or urethanization reaction is applied. can.
• Derivatives of hydroxyl group-containing compounds are preferably derivatives of polyether monools, polyether polyols, polyester polyols and polycarbonate diols, and more preferably derivatives of polyether monools.
• the derivative of polyether monool methyl ether of polyether monool and ethyl ether of polyether monool are preferable, and methyl ether of polyether monool is more preferable.
• the number average molecular weight of the derivative of the hydroxyl group-containing compound is preferably 500 or more, more preferably 500 to 30,000, even more preferably 700 to 20,000.
• the partition coefficient tends to be large, the polymer is easily separated from water, the carbon dioxide absorption does not decrease even in the presence of water, and the carbon dioxide absorption ratio increases. If the number average molecular weight is equal to or less than the upper limit, the viscosity will decrease, and the gas in the acid gas remover will easily diffuse.
• Examples of the compound to be reacted with the hydroxyl group when esterifying, etherifying, amidating or urethanizing some or all of the hydroxyl groups of the hydroxyl group-containing compound include monohydric alcohols, carboxylic acids, primary amines, secondary Class amines, monoisocyanate compounds, alkyl halides and the like can be mentioned.
• a monohydric alcohol having 1 to 30 carbon atoms is preferable, and examples thereof include methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, penta Decanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol, tetracosanol, pentacosanol, hexacosanol, heptakosanol, octacosanol, nonacosanol, triacontanol, etc.
• Carboxylic acids include, for example, formic acid, acetic acid, propionic acid, isopropionic acid, butyric acid, isobutyric acid, pivalic acid, valeric acid, and isovaleric acid.
• the primary amine is preferably a primary amine having 2 to 24 carbon atoms, such as ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, decylamine, dodecylamine. , tridecylamine, tetradecylamine, octadecylamine.
• secondary amines include dimethylamine, diethylamine, diisopropylamine, dioctylamine, didecylamine, and didodecylamine.
• monoisocyanate compounds include methyl isocyanate, ethyl isocyanate, phenyl isocyanate, cyclohexyl isocyanate, and benzyl isocyanate.
• Alkyl halides include, for example, alkyl chlorides such as methyl chloride, ethyl chloride, n-propyl chloride, isopropyl chloride, n-butyl chloride, isobutyl chloride, sec-butyl chloride, tert-butyl chloride; Alkyl bromides such as ethyl bromide, n-propyl bromide, isopropyl bromide, n-butyl bromide, isobutyl bromide, sec-butyl bromide, tert-butyl bromide; methyl iodide, ethyl iodide, iodine Alkyl iodides such as n-propyl iodide, isopropyl iodide, n-butyl iodide, isobutyl iodide, sec-butyl iodide, tert-but
• the acid gas remover may further contain an amine compound.
• the acid gas remover can be used not only for physical absorption but also for chemical absorption.
• amine compounds include 1,3-diaminopropane, 2-aminoethanol, 2-amino-1-propanol, 2-(2-aminoethoxy)ethanol, 4-amino-2-methyl-1-butanol, methyl amine, ethylamine, n-propylamine, isopropylamine, n-butylamine, tert-butylamine, diethanolamine, 2-amino-2-methyl-1-propanol, ethylenediamine, amino acids (alanine, glycine, glutamine, lysine), etc.
• the total content of one or more compounds selected from hydroxyl group-containing compounds and derivatives of hydroxyl group-containing compounds in the acid gas remover of the present invention can be appropriately set according to the mode of use, but is preferably 1 to 100% by mass. From the viewpoint of cost effectiveness, 5 to 100% by mass is more preferable, and 5 to 95% by mass is even more preferable.
• the acidic gas remover contains an amine compound
• the content of the amine compound in the acidic gas remover is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, from the viewpoint of cost effectiveness.
• Additives such as antifoaming agents, dispersion stabilizers, surfactants, viscosity modifiers and corrosion inhibitors may be added to the acidic gas remover.
• the distribution coefficient of the acid gas remover is preferably 0 or more, more preferably 1-50, and particularly preferably 1-40.
• the viscosity of the acid gas remover is preferably 1 to 20,000 mPa ⁇ s, more preferably 2 to 15,000 mPa ⁇ s, more preferably 50 to 5, from the viewpoint of an appropriate diffusion coefficient of gas in the acid gas remover. 000 mPa ⁇ s is particularly preferred.
• the carbon dioxide absorption ratio of the acid gas removing agent is 65% or more, preferably 75% or more, it can be said that carbon dioxide is removed satisfactorily. Although the detailed reason is not clear, the amount of carbon dioxide absorbed is greater in the presence of water, and the carbon dioxide absorption ratio may exceed 100% in some cases.
• the carbon dioxide absorption ratio is preferably 65 to 120%, more preferably 75 to 115%.
• the acidic gas remover of the present invention has a large distribution coefficient and low compatibility with water, so that the amount of carbon dioxide absorbed in the presence of water is higher than that in the absence of water. difficult to decrease.
• the acidic gas removing agent of the present invention has less variation in carbon dioxide absorption depending on the presence or absence of coexistence of water, and has a higher carbon dioxide absorption ratio.
• acid gas removers that have a small distribution coefficient and are easily compatible with water, the carbon dioxide adsorption sites of the acid gas remover decrease due to hydration, and the amount of carbon dioxide absorbed decreases in the presence of water. , it is presumed that the carbon dioxide absorption ratio decreases.
• Acidic gas removers that are easily compatible with water tend to have a large variation in carbon dioxide absorption ratio depending on the presence or absence of coexistence with water.
• a smaller change in the carbon dioxide absorption amount ratio makes it possible to absorb a constant amount of carbon dioxide without being affected by the amount of coexisting water, making it easier to control the carbon dioxide removal process.
• the carbon dioxide absorption ratio is calculated by the method described later.
• the acidic gas removing method of the present invention may be, for example, a method of adding the acidic gas removing agent of the present invention to an acidic gas containing carbon dioxide, and in a container filled with the acidic gas removing agent of the present invention.
• a method of continuously removing the acid gas by circulating the acid gas containing carbon dioxide in the container may be used, and the acid gas containing carbon dioxide is filled in a container filled with the acid gas removing agent of the present invention for batch processing.
• a method of removing the acid gas by using in order to increase the contact efficiency between the acidic gas removing agent of the present invention and the acidic gas containing carbon dioxide, the acidic gas removing agent and the acidic gas containing carbon dioxide are separated from each other using perforated plates, bubble cap trays, etc. in the packed tower. Alternatively, the acidic gas containing carbon dioxide may be passed through while spraying the acid gas removing agent to contact the acid gas. agent.
• the total amount of one or more compounds selected from hydroxyl group-containing compounds and hydroxyl group-containing compound derivatives contained in the acid gas remover of the present invention is gas. It is preferably added in an amount of 0.01 to 100 mol, more preferably 0.1 to 10 mol, per 1 mol of carbon dioxide in the medium.
• the temperature at which the acid gas remover is brought into contact with the gas is preferably in the range of 0 to 200°C, more preferably 25 to 60°C.
• the pressure during the treatment is preferably in the range of 0.7-7.0 MPa, more preferably 1.0-4.0 MPa.
• the gas to be treated is an acid gas containing carbon dioxide, and may contain other acid gases such as hydrogen sulfide, nitrogen, oxygen, hydrogen, and water.
• the acidic gas removing agent of the present invention exhibits a good effect of removing carbon dioxide in a nitrogen-containing gas, and also exhibits a good effect of removing carbon dioxide when the gas to be treated further contains water.
• the nitrogen content is preferably 10 to 90 vol%, more preferably 15 to 80 vol%, from the viewpoint of good carbon dioxide removal effect.
• the liquid content of water is preferably 0.5 to 20 vol%, more preferably 1 to 15 vol%, from the viewpoint of good carbon dioxide removal effect.
• the method for removing acidic gas of the present invention can be carried out, for example, by passing the gas through an absorption device filled with the agent for removing acidic gas of the present invention.
• the absorbers used may be scrubbers commonly used in gas scrubbing processes. Scrubbers include, for example, columns with random or structured packing, columns with trays, membrane contactors, radial flow scrubbers, jet scrubbers, venturi scrubbers, rotary spray scrubbers.
• the number average molecular weight of the hydroxyl group-containing compound is obtained from the hydroxyl value determined based on JIS K 1557-1: 2007, 56,100 / (hydroxyl value of the hydroxyl group-containing compound) ⁇ (number of terminal groups of the hydroxyl group-containing compound) formula It was the hydroxyl value equivalent molecular weight calculated by.
• the number average molecular weight of the hydroxyl group-containing compound derivative was measured by gel permeation chromatography (GPC) under the following measurement conditions.
• the carbon dioxide absorption ratio was obtained by the following procedures (i) to (iv).
• (i) Measurement of carbon dioxide concentration A 500 mL (volume 650 mL) three-necked flask equipped with a thermometer and a stirrer was charged with a stirrer tip, a three-way cock, a septum and a carbon dioxide concentration meter (M170, Weissera). were set respectively, and the temperature was adjusted to 40° C. while stirring at 300 rpm.
• a mixed gas of carbon dioxide/nitrogen 20 vol%/80 vol% (Yokohama Gas Chemicals Co., Ltd.) was passed through the three-necked flask at a flow rate of 1.3 L/min from a three-way cock. Using a carbon dioxide concentration meter, it was confirmed that the carbon dioxide concentration had reached about 20 vol %, and the three-way cock and the mixed gas valve were closed. The carbon dioxide concentration was recorded every minute and after 1 hour it was confirmed that the carbon dioxide concentration had stabilized. Next, 10 mL of an evaluation solution described later was measured with a syringe and injected from the septum into the three-necked flask via a needle. After injecting the evaluation solution, the carbon dioxide concentration was recorded every minute for up to 2 hours.
• Carbon dioxide absorption amount (g) n x 1 (atm) x 0.65 (L) x s/RT (1)
• R: gas constant 0.082 (atm L K -1 mol -1 )
• the carbon dioxide absorption ratio (%) is obtained from the carbon dioxide absorption amount (a) and the carbon dioxide absorption amount (b) in the presence of water, (b) / (a) ⁇ Calculated by 100.
• Partition coefficient> The partition coefficients of polypropylene glycols (PPG) with number average molecular weights of 3,200-18,000 (Examples 3-7) were obtained from ChemDraw Professional Ver. 17.1 The values obtained by extrapolating the calculated partition coefficients of PPG with number average molecular weights of 400, 700, 1,000, and 2,000 were obtained. Partition coefficients for other polymers and compounds are obtained from ChemDraw Professional Ver. 17.1 calculated by software package.
• Table 1 shows the measurement evaluation results for the evaluation liquids A1 to A10 and the evaluation liquids A'1 and A'2.
• the evaluation liquids A1 to A10 of Examples 1 to 10 use the polymers A1 to A10, the propylene glycol (PG) of the evaluation liquid A'1 of Example 11 is manufactured by AGC, and the polyethylene glycol of the evaluation liquid A'2 of Example 12.
• Dimethyl ether (DMPEG) used was manufactured by Tokyo Chemical Industry Co., Ltd.
• DMPEG dimethyl ether
• Table 1-10 the molecular weight is described in the number average molecular weight column. Examples 1-10 are working examples, and examples 11 and 12 are comparative examples.
• An acid gas remover containing a hydroxyl group-containing compound or a derivative of a hydroxyl group-containing compound having a number average molecular weight of 500 or more has a distribution coefficient of 0 or more, is not compatible with water, and is less likely to absorb carbon dioxide in the presence of water. , the carbon dioxide absorption ratio was high.
• an acidic gas remover containing a hydroxyl group-containing compound or a derivative of a hydroxyl group-containing compound having a number average molecular weight of 500 or more is used, compared with the case of using an acidic gas remover containing a hydroxyl group-containing compound having a number average molecular weight of less than 500. , the amount of carbon dioxide uptake could be maintained even in the coexistence of water, and the fluctuation of the amount of carbon dioxide uptake was small.

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