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WO2018100566A1 - Composition for recovering carbon dioxide and method for recovering carbon dioxide - Google Patents

Composition for recovering carbon dioxide and method for recovering carbon dioxide Download PDF

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Publication number
WO2018100566A1
WO2018100566A1 PCT/IB2018/000031 IB2018000031W WO2018100566A1 WO 2018100566 A1 WO2018100566 A1 WO 2018100566A1 IB 2018000031 W IB2018000031 W IB 2018000031W WO 2018100566 A1 WO2018100566 A1 WO 2018100566A1
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carbon dioxide
ionic liquid
absorption
melting point
temperature
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PCT/IB2018/000031
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French (fr)
Japanese (ja)
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健太郎 植田
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大阪瓦斯株式会社
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • 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
    • 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
    • B01D53/81—Solid phase processes
    • 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
    • B01D53/81—Solid phase processes
    • B01D53/82—Solid phase processes with stationary reactants
    • 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
    • B01D53/96—Regeneration, reactivation or recycling of reactants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/50—Carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C211/00—Compounds containing amino groups bound to a carbon skeleton
    • C07C211/62—Quaternary ammonium compounds
    • C07C211/63—Quaternary ammonium compounds having quaternised nitrogen atoms bound to acyclic carbon atoms
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/151—Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Definitions

  • the present invention relates to a carbon dioxide recovery composition containing an ionic liquid, and a carbon dioxide recovery method using the carbon dioxide recovery composition.
  • Patent Document 1 proposes a carbon dioxide separation and recovery method in which CO 2 is separated and recovered from a multicomponent mixed gas by a physical absorption method using an ionic liquid absorbing liquid.
  • absorption of carbon dioxide into an ionic liquid is an exothermic reaction.
  • the temperature of the ionic liquid is increased due to heat generation, the absorption rate of carbon dioxide is not preferable.
  • the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a carbon dioxide recovery composition and a carbon dioxide recovery method that are advantageous in terms of heat balance when recovering carbon dioxide.
  • the characteristic configuration of the carbon dioxide recovery composition for achieving the above object is a carbon dioxide recovery composition containing an ionic liquid, which is an absorption state that is a melting point of the ionic liquid in a state of absorbing carbon dioxide
  • the melting point is 50 ° C. or more and 110 ° C. or less, and the melting point or decomposition temperature of the ionic liquid in a state where carbon dioxide is desorbed is higher than the absorption state melting point.
  • Carbon dioxide recovery is performed on exhaust gas (hereinafter referred to as processing gas) from engines and boilers in factories and power plants.
  • the temperature of these processing gases is generally about 60 ° C to 120 ° C.
  • the inventors have conceived to mitigate the adverse effects of heat generation due to absorption of carbon dioxide in this temperature range by utilizing heat generation and heat absorption associated with phase transition of the ionic liquid. And measure the melting point of the ionic liquid in the state of absorbing carbon dioxide of some ionic liquids, confirm that these ionic liquids cause a phase transition in the temperature range of general processing gas, carbon dioxide recovery As a result, the present invention was completed.
  • the absorption state melting point which is the melting point of the ionic liquid in the state of absorbing carbon dioxide
  • the carbon dioxide recovery composition containing the ionic liquid can be suitably used for carbon dioxide recovery.
  • Another characteristic configuration of the carbon dioxide recovery composition according to the present invention is that the ionic liquid contains tetraethylammonium benzimidazolide.
  • the absorption state melting point of tetraethylammonium benzimidazolide (hereinafter sometimes referred to as “N2Bn”) measured by the inventors is 55 ° C.
  • N2Bn tetraethylammonium benzimidazolide
  • Another characteristic configuration of the carbon dioxide recovery composition according to the present invention is that the ionic liquid contains tetraethylammonium imidazolide.
  • the absorption melting point of tetraethylammonium imidazolide (hereinafter sometimes referred to as “N2Im”) measured by the inventor is 70 ° C.
  • N2Im tetraethylammonium imidazolide
  • the carbon dioxide recovery composition can be suitably used for recovering carbon dioxide from a processing gas having a temperature higher than 70 ° C.
  • Another characteristic configuration of the carbon dioxide recovery composition according to the present invention is that the ionic liquid contains tetrabutylammonium carbazolide.
  • the absorption melting point of tetrabutylammonium carbazolide (hereinafter sometimes referred to as “N4Cz”) measured by the inventor is 100 ° C.
  • N4Cz tetrabutylammonium carbazolide
  • the characteristic configuration of the carbon dioxide recovery method for achieving the above object is a carbon dioxide recovery method having an absorption step
  • the absorption step is a step in which a treatment gas containing carbon dioxide is brought into contact with a carbon dioxide recovery composition containing an ionic liquid to absorb carbon dioxide into the ionic liquid;
  • the absorption state melting point which is the melting point of the ionic liquid in a state of absorbing carbon dioxide, is 50 ° C. or more and 110 ° C. or less, and the melting point or decomposition temperature of the ionic liquid in the state of removing carbon dioxide is the absorption state melting point.
  • Higher than The absorption process temperature at which the absorption process is performed is higher than the absorption state melting point.
  • Carbon dioxide recovery is performed on exhaust gas (hereinafter referred to as processing gas) from engines and boilers in factories and power plants.
  • the temperature of these processing gases is generally about 60 ° C to 120 ° C.
  • the inventors have conceived to mitigate the adverse effects of heat generation due to absorption of carbon dioxide in this temperature range by utilizing heat generation and heat absorption associated with phase transition of the ionic liquid. And measure the melting point of the ionic liquid in the state of absorbing carbon dioxide of some ionic liquids, confirm that these ionic liquids cause a phase transition in the temperature range of general processing gas, carbon dioxide recovery As a result, the present invention was completed.
  • the absorption state melting point of the ionic liquid in the state of absorbing carbon dioxide is 50 ° C. or higher and 110 ° C. or lower, and the melting point or decomposition temperature of the ionic liquid in the state of desorbing carbon dioxide is higher than the absorption state melting point.
  • the absorption process is performed using the carbon dioxide recovery composition containing the ionic liquid, and the absorption process temperature at which the absorption process is performed is higher than the absorption state melting point.
  • the carbon dioxide can be recovered in an advantageous state.
  • the regeneration step is a step of heating the carbon dioxide recovery composition to desorb carbon dioxide, and is performed after the absorption step,
  • the regeneration process temperature at which the regeneration process is performed is higher than the absorption process temperature and lower than the melting point and decomposition temperature of the ionic liquid.
  • FIG. 1 is a schematic configuration diagram of a temperature swing adsorption device in which a carbon dioxide recovery method using a carbon dioxide recovery composition is performed.
  • An ionic liquid is an organic salt that is melted without crystallization even at room temperature.
  • the composition for carbon dioxide recovery according to this embodiment is configured to contain the above-described ionic liquid.
  • the ionic liquid according to the present embodiment has an absorption state melting point that is a melting point of the ionic liquid in a state where carbon dioxide is absorbed is 50 ° C. or higher and 110 ° C. or lower, and a melting point of the ionic liquid in a state where carbon dioxide is desorbed or A decomposition temperature higher than the absorption state melting point is used.
  • Examples of the ionic liquid having such characteristics include tetraethylammonium benzimidazolide (N2Bn), tetraethylammonium imidazolide (N2Im), and tetrabutylammonium carbazolide (N4Cz).
  • N2Bn tetraethylammonium benzimidazolide
  • N2Im tetraethylammonium imidazolide
  • N4Cz tetrabutylammonium carbazolide
  • Tetraethylammonium benzimidazolide (tetraethyl ammoniumbenzimidazolide, N2Bn) is cationic: tetraethylammonium (tetraethylammonium, N 2222) and an anion: A benzimidazole (benzimidazole, BnIm) and salts, ionic liquids represented by the following formula 1 It is.
  • N2Bn can be synthesized by reacting tetraethylammonium hydroxide and benzimidazole. Specifically, it can be synthesized by the following procedure.
  • the absorption state melting point (Tmad) of N2Bn and the melting point or decomposition temperature (Tmde) of the ionic liquid in a state where carbon dioxide was desorbed were measured as follows.
  • Tmad About 1 g of N2Bn was put into the flask, the inside of the flask was evacuated to 0.1 kPa or less, and then the flask was heated from room temperature to 150 ° C. at a rate of 0.5 ° C./min with 14 kPa of carbon dioxide gas supplied. The temperature was raised. N2Bn was visually observed, and the temperature at which N2Bn was liquefied and about half was transparent was defined as Tmad. The Tmad of N2Bn was measured to be 55 ° C.
  • Tetraethylammonium imidazolide (tetraethylammoniumimidazolide, N2Im) is cationic: tetraethylammonium (tetraethylammonium, N 2222) and an anion: a salt with imidazole (imidazole, Im), it is an ionic liquid represented by the following Formula 2.
  • N2Im can be synthesized by reacting tetraethylammonium hydroxide and imidazole. Specifically, it can be synthesized by the following procedure.
  • a 100 ml three-necked reactor equipped with a dropping funnel and a three-way cock is charged with 0.82 g of imidazole (because it is a 98% product, 0.80 g, 11.8 mmol) and 4.0 ml of methanol, and stirred at room temperature. 4.94 g of 35% tetraethylammonium hydroxide solution (1.73 g, 11.8 mmol because it is a 35% product) is dropped from the dropping funnel. Thereafter, the dropping funnel is washed with methanol (2.0 ml), and the methanol solution is also dropped into the reaction system. After stirring at room temperature for 1 day, the solvent of this reaction mixture is distilled off and dried under reduced pressure (60 ° C. 17 hr) to obtain 1.45 g of a white solid.
  • the absorption melting point (Tmad) of N2Im and the melting point or decomposition temperature (Tmde) of the ionic liquid in a state where carbon dioxide was desorbed were measured as follows, similarly to N2Bn.
  • Tmad About 1 g of N2Im was put into the flask, the inside of the flask was evacuated to 0.1 kPa or less, and then the flask was supplied at a rate of 0.5 ° C./min from room temperature to 150 ° C. while supplying 14 kPa of carbon dioxide gas. The temperature was raised. N2Im was visually observed, and the temperature at the time when N2Im liquefied and about half of the amount became transparent was defined as Tmad. The Tmad of N2Im was measured as 70 ° C.
  • Tmde Treatment temperature
  • Tetrabutylammonium carbazolyl de (tetrabuthylammoniumcarbazolide, N4Cz) is cationic: tetrabutylammonium (tetrabuthylammonium, N 4444) and an anion: carbazole (carbazole, Cz) is a salt with an ionic liquid represented by the following Formula 3 It is.
  • N4Cz can be synthesized by reacting tetrabutylammonium hydroxide with carbazole. Specifically, it can be synthesized by the following procedure.
  • a 100 ml three-necked reactor equipped with a dropping funnel and a three-way cock is charged with 0.67 g of carbazole (because it is a 96% product, 0.64 g, 3.85 mmol) and 5.0 ml of THF, and stirred at room temperature.
  • a dropping funnel 10.00 g of a 10% tetrabutylammonium hydroxide methanol solution (1.00 g, 3.85 mmol because it is a 10% product) is dropped.
  • the dropping funnel is washed with THF (2.0 ml), and the THF solution is also dropped into the reaction system.
  • the solvent of this reaction mixture is distilled off and dried under reduced pressure (60 ° C., 17 hr) to obtain 1.26 g of a yellow solid.
  • the absorption melting point (Tmad) of N4Cz and the melting point or decomposition temperature (Tmde) of the ionic liquid in a state where carbon dioxide was desorbed were measured as follows in the same manner as N2Bn.
  • Tmad About 1 g of N4Cz was put into the flask, the inside of the flask was evacuated to 0.1 kPa or less, and then the flask was supplied at a rate of 0.5 ° C./min from room temperature to 150 ° C. while supplying 14 kPa of carbon dioxide gas. The temperature was raised. N4Cz was visually observed, and the temperature at which N4Cz was liquefied and about half was transparent was defined as Tmad. The N4Cz Tmad was measured at 100 ° C.
  • Tmde melting temperature
  • composition for recovering carbon dioxide containing an ionic liquid can be used for recovering carbon dioxide in a liquid state. Further, it is more preferable to use a carbon dioxide recovery composition containing an ionic liquid for carbon dioxide recovery in a state of being supported on a carrier.
  • Examples of applicable carriers include capsules and porous inorganic particles.
  • the capsule for example, a core-shell type capsule or a sea-island structure type capsule that is configured so that the gas absorbing material is not exposed to the surface is preferable. That is, the gas absorbing material is disposed on the inner side, and the outer side of the gas absorbing material is covered with a film or an outer shell.
  • the porous inorganic particles are preferably those that penetrate to the surface but do not elute even when the gas absorbing material is liquefied because the pore diameter is small.
  • Examples of inorganic substances forming the porous inorganic particles include silicates, phosphates, oxides, and the like.
  • Examples of the silicate include calcium silicate, barium silicate, magnesium silicate, and zeolite.
  • Examples of the phosphate include calcium phosphate, barium phosphate, magnesium phosphate, zirconium phosphate, and apatite.
  • Examples of the oxide include silicon oxide such as silicon dioxide and silicon monoxide, and alumina. Preferred is an oxide, more preferred is silicon oxide, and even more preferred is silicon dioxide.
  • the temperature swing adsorption device 1 in this embodiment includes a first absorption tank 2, a second absorption tank 3, a steam supply line 4, a process gas supply line 5, a carbon dioxide recovery line 6, an exhaust line 7, and a blower 8.
  • the gas absorbing material 9 is filled in each of the first absorption tank 2 and the second absorption tank 3.
  • the gas absorbent 9 is obtained by supporting the above-described carbon dioxide recovery composition on a carrier.
  • processing gas applicable to the temperature swing adsorption device 1 for example, industrial processing gas discharged from a thermal power plant, a steelworks blast furnace, an automobile and the like can be mentioned.
  • the processing gas is supplied to the first absorption tank 2 through the processing gas supply line 5 for a predetermined time, and the gas absorbent 9 absorbs carbon dioxide contained in the processing gas (absorption process).
  • the remaining gas components are discharged via the exhaust line 7.
  • the processing gas supply line 5 is switched to supply the processing gas to the second absorption tank 3 for a predetermined time, and high-temperature steam is supplied to the first absorption tank 2 through the vapor supply line 4 for a predetermined time. Then, carbon dioxide is desorbed to regenerate the gas absorbent 9 (regeneration step). The desorbed carbon dioxide is recovered via the carbon dioxide recovery line 6.
  • the processing gas supply line 5 is switched to supply the processing gas to the first absorption tank 2 again for a predetermined time, and the steam supply line 4 is switched to supply steam to the second absorption tank 3 for a predetermined time. And heated to desorb carbon dioxide to regenerate the gas absorbent 9.
  • an absorption process is performed in which the gas absorbent 9 is brought into contact with the processing gas and carbon dioxide is absorbed.
  • the carbon dioxide is removed by heating.
  • the regeneration step of regenerating the gas absorbing material 9 is operated, and is configured to switch every predetermined time. Therefore, carbon dioxide in the processing gas can be continuously separated and recovered.
  • phase change of the ionic liquid in the absorption process and the regeneration process described above will be described by taking as an example the case of using tetraethylammonium benzimidazolide (N2Bn) as the ionic liquid.
  • the regeneration step of the present embodiment is a step of heating the carbon dioxide recovery composition to desorb carbon dioxide.
  • N2Im tetraethylammonium imidazolide
  • the above-described temperature swing adsorption device 1 may further include a condenser. Since the recovered carbon dioxide contains moisture, only the carbon dioxide can be separated and recovered by removing the moisture with a condenser. The removed water can be reused as steam.
  • the above-described temperature swing adsorption device may be combined with a pressure swing method as necessary, or only the pressure swing method may be adopted instead of the temperature swing method.
  • the pressure swing method during the regeneration process, the carbon dioxide recovery line is pulled by a pump to make the inside of the absorption tank have a reduced pressure, so that regeneration of the gas absorbent can be promoted.
  • the gas absorbent 9 is filled in the first absorbent tank 2 and the second absorbent tank 3, and carbon dioxide is recovered without the gas absorbent 9 moving. And in the 1st absorption tank 2 and the 2nd absorption tank 3, an absorption process and a regeneration process are performed by turns.
  • the absorption process is performed in one tank (absorption tower), the regeneration process is performed in the other tank (regeneration tower), and the gas absorbent 9 (carrier carrying ionic liquid) is put into two tanks. It may be circulated. Specifically, the gas absorbent 9 comes into contact with the processing gas in the absorption tower, and the ionic liquid absorbs carbon dioxide and melts.
  • the gas absorbent 9 is transferred to the regeneration tower and heated by high-temperature steam, and the ionic liquid releases carbon dioxide and solidifies. And the gas absorption material 9 is moved to an absorption tower again.
  • the pressure swing method may be combined with the temperature swing method, or only the pressure swing method may be adopted instead of the temperature swing method.
  • the gas absorbent material 9 in a liquid state may be configured as follows. Then, the gas absorbent 9 in the liquid state may be circulated to the absorption tower / regeneration tower described above.

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Abstract

Provided are a composition for recovering carbon dioxide and a method for recovering carbon dioxide, which are advantageous in terms of heat balance during carbon dioxide recovery. A composition for recovering carbon dioxide, said composition containing an ionic liquid, wherein an absorption-state melting point, which is the melting point of the ionic liquid with carbon dioxide absorbed therein is between 50-110°C inclusive, and the decomposition temperature or melting point of the ionic liquid with carbon dioxide desorbed therefrom is higher than the absorption-state melting point.

Description

二酸化炭素回収用組成物および二酸化炭素回収方法Carbon dioxide recovery composition and carbon dioxide recovery method
　本発明は、イオン液体を含有する二酸化炭素回収用組成物、および二酸化炭素回収用組成物を利用した二酸化炭素回収方法に関する。 The present invention relates to a carbon dioxide recovery composition containing an ionic liquid, and a carbon dioxide recovery method using the carbon dioxide recovery composition.
　これまでの研究（非特許文献１、２）により、イオン液体は、従来の物理吸収液より、優れた二酸化炭素吸収量を持つことが明らかにされている。特許文献１では、イオン液体吸収液を用いた物理吸収法により、多成分混合ガスからＣＯ２を分離回収する二酸化炭素分離回収方法が提案されている。 From previous studies (Non-Patent Documents 1 and 2), it has been clarified that the ionic liquid has a carbon dioxide absorption superior to that of the conventional physical absorption liquid. Patent Document 1 proposes a carbon dioxide separation and recovery method in which CO 2 is separated and recovered from a multicomponent mixed gas by a physical absorption method using an ionic liquid absorbing liquid.
特許第５４６７３９４号明細書Japanese Patent No. 5467394
　一般に、イオン液体への二酸化炭素の吸収は発熱反応であるが、発熱によりイオン液体の温度が上昇すると、二酸化炭素の吸収率が低下してしまい好ましくない。 Generally, absorption of carbon dioxide into an ionic liquid is an exothermic reaction. However, when the temperature of the ionic liquid is increased due to heat generation, the absorption rate of carbon dioxide is not preferable.
　本発明は上述の課題に鑑みてなされたものであり、その目的は、二酸化炭素の回収に際して熱収支の面で有利な二酸化炭素回収用組成物および二酸化炭素回収方法を提供することにある。 The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a carbon dioxide recovery composition and a carbon dioxide recovery method that are advantageous in terms of heat balance when recovering carbon dioxide.
　上記目的を達成するための二酸化炭素回収用組成物の特徴構成は、イオン液体を含有する二酸化炭素回収用組成物であって、二酸化炭素を吸収した状態での前記イオン液体の融点である吸収状態融点が５０℃以上１１０℃以下であり、二酸化炭素を脱離した状態での前記イオン液体の融点または分解温度が前記吸収状態融点よりも高い点にある。 The characteristic configuration of the carbon dioxide recovery composition for achieving the above object is a carbon dioxide recovery composition containing an ionic liquid, which is an absorption state that is a melting point of the ionic liquid in a state of absorbing carbon dioxide The melting point is 50 ° C. or more and 110 ° C. or less, and the melting point or decomposition temperature of the ionic liquid in a state where carbon dioxide is desorbed is higher than the absorption state melting point.
　二酸化炭素の回収は、工場や発電所等のエンジンやボイラー等の排気ガス等（以下、処理ガス）に対して行われる。これらの処理ガスの温度は一般に、６０℃~１２０℃程度である。発明者らは、この温度域での二酸化炭素の吸収に伴う発熱の悪影響を、イオン液体の相転移に伴う発熱・吸熱を利用して緩和することに想到した。そして幾つかのイオン液体の、二酸化炭素を吸収した状態でのイオン液体の融点を測定し、それらイオン液体が一般的な処理ガスの温度範囲で相転移を起こすことを確認して、二酸化炭素回収の用途に好適に用い得ることを見出し、本発明を完成したのである。 Carbon dioxide recovery is performed on exhaust gas (hereinafter referred to as processing gas) from engines and boilers in factories and power plants. The temperature of these processing gases is generally about 60 ° C to 120 ° C. The inventors have conceived to mitigate the adverse effects of heat generation due to absorption of carbon dioxide in this temperature range by utilizing heat generation and heat absorption associated with phase transition of the ionic liquid. And measure the melting point of the ionic liquid in the state of absorbing carbon dioxide of some ionic liquids, confirm that these ionic liquids cause a phase transition in the temperature range of general processing gas, carbon dioxide recovery As a result, the present invention was completed.
　すなわち上述の特徴構成によれば、二酸化炭素を吸収した状態でのイオン液体の融点である吸収状態融点が５０℃以上１１０℃以下であり、二酸化炭素を脱離した状態でのイオン液体の融点または分解温度が吸収状態融点よりも高いことによって、固体状態のイオン液体が６０℃~１２０℃程度の処理ガスに接触して二酸化炭素を吸収すると、融点が低下して、固体状態のイオン液体は融解する。その際にイオン液体は融解熱を吸収するから、二酸化炭素吸収に伴う発熱の影響を緩和することができる。また液体状態のイオン液体から二酸化炭素が脱離すると、融点が上昇して、液体状態のイオン液体は凝固する。その際にイオン液体は凝固熱を放出するから、二酸化炭素脱離に伴う吸熱の影響を緩和することができる。以上の作用機序により、上述のイオン液体を含有する二酸化炭素回収用組成物は、二酸化炭素の回収の用途に好適に用い得る。 That is, according to the above-described feature configuration, the absorption state melting point, which is the melting point of the ionic liquid in the state of absorbing carbon dioxide, is 50 ° C. or higher and 110 ° C. or lower, and the melting point of the ionic liquid in the state of desorbing carbon dioxide or When the decomposition temperature is higher than the absorption state melting point, when the solid state ionic liquid comes into contact with the processing gas of about 60 ° C. to 120 ° C. and absorbs carbon dioxide, the melting point decreases and the solid state ionic liquid melts. To do. At that time, since the ionic liquid absorbs the heat of fusion, the influence of heat generation accompanying the absorption of carbon dioxide can be mitigated. Further, when carbon dioxide is desorbed from the liquid ionic liquid, the melting point increases and the liquid ionic liquid is solidified. At that time, since the ionic liquid releases heat of solidification, it is possible to reduce the influence of the endotherm accompanying carbon dioxide desorption. With the above mechanism of action, the carbon dioxide recovery composition containing the ionic liquid can be suitably used for carbon dioxide recovery.
　本発明に係る二酸化炭素回収用組成物の別の特徴構成は、前記イオン液体が、テトラエチルアンモニウムベンゾイミダゾリドを含む点にある。 Another characteristic configuration of the carbon dioxide recovery composition according to the present invention is that the ionic liquid contains tetraethylammonium benzimidazolide.
　発明者によって測定された、テトラエチルアンモニウムベンゾイミダゾリド（以下「Ｎ２Ｂｎ」と記す場合がある。）の吸収状態融点は５５℃である。そうすると、５５℃より高い温度の処理ガスに二酸化炭素回収用組成物が接触すると、固体状態のイオン液体が二酸化炭素を吸収して融点が５５℃となり、融解する。すなわち上述の特徴構成によれば、二酸化炭素回収用組成物を、５５℃より高い温度の処理ガスからの二酸化炭素の回収用途に好適に用い得る。 The absorption state melting point of tetraethylammonium benzimidazolide (hereinafter sometimes referred to as “N2Bn”) measured by the inventors is 55 ° C. Then, when the carbon dioxide recovery composition comes into contact with a processing gas having a temperature higher than 55 ° C., the solid ionic liquid absorbs carbon dioxide and has a melting point of 55 ° C. and melts. That is, according to the above-described feature configuration, the carbon dioxide recovery composition can be suitably used for recovering carbon dioxide from a processing gas having a temperature higher than 55 ° C.
　本発明に係る二酸化炭素回収用組成物の別の特徴構成は、前記イオン液体が、テトラエチルアンモニウムイミダゾリドを含む点にある。 Another characteristic configuration of the carbon dioxide recovery composition according to the present invention is that the ionic liquid contains tetraethylammonium imidazolide.
　発明者によって測定された、テトラエチルアンモニウムイミダゾリド（以下「Ｎ２Ｉｍ」と記す場合がある。）の吸収状態融点は７０℃である。そうすると、７０℃より高い温度の処理ガスに二酸化炭素回収用組成物が接触すると、固体状態のイオン液体が二酸化炭素を吸収して融点が７０℃となり、融解する。すなわち上述の特徴構成によれば、二酸化炭素回収用組成物を、７０℃より高い温度の処理ガスからの二酸化炭素の回収用途に好適に用い得る。 The absorption melting point of tetraethylammonium imidazolide (hereinafter sometimes referred to as “N2Im”) measured by the inventor is 70 ° C. Then, when the composition for recovering carbon dioxide comes into contact with a processing gas having a temperature higher than 70 ° C., the solid ionic liquid absorbs carbon dioxide and has a melting point of 70 ° C. and melts. That is, according to the above-described characteristic configuration, the carbon dioxide recovery composition can be suitably used for recovering carbon dioxide from a processing gas having a temperature higher than 70 ° C.
　本発明に係る二酸化炭素回収用組成物の別の特徴構成は、前記イオン液体が、テトラブチルアンモニウムカルバゾリドを含む点にある。 Another characteristic configuration of the carbon dioxide recovery composition according to the present invention is that the ionic liquid contains tetrabutylammonium carbazolide.
　発明者によって測定された、テトラブチルアンモニウムカルバゾリド（以下「Ｎ４Ｃｚ」と記す場合がある。）の吸収状態融点は１００℃である。そうすると、１００℃より高い温度の処理ガスに二酸化炭素回収用組成物が接触すると、固体状態のイオン液体が二酸化炭素を吸収して融点が１００℃となり、融解する。すなわち上述の特徴構成によれば、二酸化炭素回収用組成物を、１００℃より高い温度の処理ガスからの二酸化炭素の回収用途に好適に用い得る。 The absorption melting point of tetrabutylammonium carbazolide (hereinafter sometimes referred to as “N4Cz”) measured by the inventor is 100 ° C. Then, when the composition for recovering carbon dioxide comes into contact with a processing gas having a temperature higher than 100 ° C., the solid ionic liquid absorbs carbon dioxide and has a melting point of 100 ° C. and melts. That is, according to the above-described characteristic configuration, the composition for recovering carbon dioxide can be suitably used for recovering carbon dioxide from a processing gas having a temperature higher than 100 ° C.
　上記目的を達成するための二酸化炭素回収方法の特徴構成は、吸収工程を有する二酸化炭素回収方法であって、
　前記吸収工程は、二酸化炭素を含有する処理ガスをイオン液体を含有する二酸化炭素回収用組成物に接触させて、二酸化炭素を前記イオン液体に吸収させる工程であり、
　二酸化炭素を吸収した状態での前記イオン液体の融点である吸収状態融点が５０℃以上１１０℃以下であり、二酸化炭素を脱離した状態での前記イオン液体の融点または分解温度が前記吸収状態融点よりも高く、
　前記吸収工程が行われる吸収工程温度は前記吸収状態融点よりも高い点にある。 The characteristic configuration of the carbon dioxide recovery method for achieving the above object is a carbon dioxide recovery method having an absorption step,
The absorption step is a step in which a treatment gas containing carbon dioxide is brought into contact with a carbon dioxide recovery composition containing an ionic liquid to absorb carbon dioxide into the ionic liquid;
The absorption state melting point, which is the melting point of the ionic liquid in a state of absorbing carbon dioxide, is 50 ° C. or more and 110 ° C. or less, and the melting point or decomposition temperature of the ionic liquid in the state of removing carbon dioxide is the absorption state melting point. Higher than
The absorption process temperature at which the absorption process is performed is higher than the absorption state melting point.
　二酸化炭素の回収は、工場や発電所等のエンジンやボイラー等の排気ガス等（以下、処理ガス）に対して行われる。これらの処理ガスの温度は一般に、６０℃~１２０℃程度である。発明者らは、この温度域での二酸化炭素の吸収に伴う発熱の悪影響を、イオン液体の相転移に伴う発熱・吸熱を利用して緩和することに想到した。そして幾つかのイオン液体の、二酸化炭素を吸収した状態でのイオン液体の融点を測定し、それらイオン液体が一般的な処理ガスの温度範囲で相転移を起こすことを確認して、二酸化炭素回収の用途に好適に用い得ることを見出し、本発明を完成したのである。 Carbon dioxide recovery is performed on exhaust gas (hereinafter referred to as processing gas) from engines and boilers in factories and power plants. The temperature of these processing gases is generally about 60 ° C to 120 ° C. The inventors have conceived to mitigate the adverse effects of heat generation due to absorption of carbon dioxide in this temperature range by utilizing heat generation and heat absorption associated with phase transition of the ionic liquid. And measure the melting point of the ionic liquid in the state of absorbing carbon dioxide of some ionic liquids, confirm that these ionic liquids cause a phase transition in the temperature range of general processing gas, carbon dioxide recovery As a result, the present invention was completed.
　二酸化炭素を吸収した状態でのイオン液体の融点である吸収状態融点が５０℃以上１１０℃以下であり、二酸化炭素を脱離した状態でのイオン液体の融点または分解温度が吸収状態融点よりも高いことによって、固体状態のイオン液体が６０℃~１２０℃程度の処理ガスに接触して二酸化炭素を吸収すると、融点が低下して、固体状態のイオン液体は融解する。その際にイオン液体は融解熱を吸収するから、二酸化炭素吸収に伴う発熱の影響を緩和することができる。すなわち上述の特徴構成によれば、イオン液体を含有する二酸化炭素回収用組成物を用いて吸収工程を行い、吸収工程が行われる吸収工程温度は吸収状態融点よりも高いことにより、熱収支の面で有利な状態で二酸化炭素の回収を行うことができる。 The absorption state melting point of the ionic liquid in the state of absorbing carbon dioxide is 50 ° C. or higher and 110 ° C. or lower, and the melting point or decomposition temperature of the ionic liquid in the state of desorbing carbon dioxide is higher than the absorption state melting point. Thus, when the solid state ionic liquid comes into contact with the processing gas of about 60 ° C. to 120 ° C. and absorbs carbon dioxide, the melting point is lowered and the solid state ionic liquid is melted. At that time, since the ionic liquid absorbs the heat of fusion, the influence of heat generation accompanying the absorption of carbon dioxide can be mitigated. That is, according to the above-described feature configuration, the absorption process is performed using the carbon dioxide recovery composition containing the ionic liquid, and the absorption process temperature at which the absorption process is performed is higher than the absorption state melting point. The carbon dioxide can be recovered in an advantageous state.
　本発明に係る二酸化炭素回収方法の別の特徴構成は、再生工程を有し、
　前記再生工程は、前記二酸化炭素回収用組成物を加熱して二酸化炭素を脱離させる工程であり、前記吸収工程の次に行われ、
　前記再生工程が行われる再生工程温度は、前記吸収工程温度よりも高く、前記イオン液体の融点および分解温度よりも低い点にある。 Another characteristic configuration of the carbon dioxide recovery method according to the present invention includes a regeneration step,
The regeneration step is a step of heating the carbon dioxide recovery composition to desorb carbon dioxide, and is performed after the absorption step,
The regeneration process temperature at which the regeneration process is performed is higher than the absorption process temperature and lower than the melting point and decomposition temperature of the ionic liquid.
　上記の特徴構成によれば、再生工程温度が吸収工程温度よりも高くイオン液体の融点および分解温度よりも低いことによって、再生工程で二酸化炭素回収用組成物から二酸化炭素が脱離し、融点が上昇して液体状態のイオン液体は凝固する。その際にイオン液体は凝固熱を放出するから、二酸化炭素脱離に伴う吸熱の影響を緩和することができる。したがって熱収支の面で有利な状態で二酸化炭素の回収を行うことができる。 According to the above characteristic configuration, when the regeneration process temperature is higher than the absorption process temperature and lower than the melting point and decomposition temperature of the ionic liquid, carbon dioxide is desorbed from the carbon dioxide recovery composition in the regeneration process, and the melting point increases. Thus, the ionic liquid in the liquid state is solidified. At that time, since the ionic liquid releases heat of solidification, it is possible to reduce the influence of the endotherm accompanying carbon dioxide desorption. Therefore, carbon dioxide can be recovered in a state advantageous in terms of heat balance.
［図１］は、二酸化炭素回収用組成物を用いた二酸化炭素回収方法が行われる温度スイング吸着装置の概略構成図である。 FIG. 1 is a schematic configuration diagram of a temperature swing adsorption device in which a carbon dioxide recovery method using a carbon dioxide recovery composition is performed.
　まず本実施形態に係る二酸化炭素回収用組成物およびイオン液体について説明する。イオン液体とは、常温でも結晶化せずに溶融している有機塩である。本実施形態に係る二酸化炭素回収用組成物は、上述のイオン液体を含有して構成される。 First, the carbon dioxide recovery composition and ionic liquid according to this embodiment will be described. An ionic liquid is an organic salt that is melted without crystallization even at room temperature. The composition for carbon dioxide recovery according to this embodiment is configured to contain the above-described ionic liquid.
　本実施形態に係るイオン液体は、二酸化炭素を吸収した状態でのイオン液体の融点である吸収状態融点が５０℃以上１１０℃以下であり、二酸化炭素を脱離した状態でのイオン液体の融点または分解温度が吸収状態融点よりも高いものが用いられる。 The ionic liquid according to the present embodiment has an absorption state melting point that is a melting point of the ionic liquid in a state where carbon dioxide is absorbed is 50 ° C. or higher and 110 ° C. or lower, and a melting point of the ionic liquid in a state where carbon dioxide is desorbed or A decomposition temperature higher than the absorption state melting point is used.
　このような特性を有するイオン液体としては、テトラエチルアンモニウムベンゾイミダゾリド（Ｎ２Ｂｎ）、テトラエチルアンモニウムイミダゾリド（Ｎ２Ｉｍ）、テトラブチルアンモニウムカルバゾリド（Ｎ４Ｃｚ）を例示することができる。 Examples of the ionic liquid having such characteristics include tetraethylammonium benzimidazolide (N2Bn), tetraethylammonium imidazolide (N2Im), and tetrabutylammonium carbazolide (N4Cz).
　テトラエチルアンモニウムベンゾイミダゾリド（ｔｅｔｒａｅｔｈｙｌ　ａｍｍｏｎｉｕｍｂｅｎｚｉｍｉｄａｚｏｌｉｄｅ、Ｎ２Ｂｎ）は、カチオン：テトラエチルアンモニウム（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ、Ｎ２２２２）と、アニオン：ベンゾイミダゾール（ｂｅｎｚｉｍｉｄａｚｏｌｅ、ＢｎＩｍ）との塩であり、以下の化１で表されるイオン液体である。 Tetraethylammonium benzimidazolide (tetraethyl ammoniumbenzimidazolide, N2Bn) is cationic: tetraethylammonium (tetraethylammonium, N 2222) and an anion: A benzimidazole (benzimidazole, BnIm) and salts, ionic liquids represented by the following formula 1 It is.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　Ｎ２Ｂｎは、テトラエチルアンモニウムヒドロキシドとベンゾイミダゾールとを反応させて合成することができる。具体的には、以下の手順で合成することができる。 N2Bn can be synthesized by reacting tetraethylammonium hydroxide and benzimidazole. Specifically, it can be synthesized by the following procedure.
　滴下漏斗と三方コックを装着した１００ｍｌ三つ口反応器にベンゾイミダゾール２．００ｇ（９８％品であるため実質、１．９６ｇ，１６．６ｍｍｏｌ）、メタノール５．５ｍｌを仕込み、室温撹拌する。滴下漏斗より３５％テトラエチルアンモニウムヒドロキシド溶液６．９８ｇ（３５％品であるため２．４４ｇ、１６．６ｍｍｏｌ）を滴下する。その後、滴下漏斗をメタノール（２．８ｍｌ）で洗い、そのメタノール溶液も反応系中に滴下する。室温で１日撹拌したのち、この反応混合液の溶媒を溜去して減圧乾燥（６０℃１７ｈｒ）することで白色固体３．７２ｇを得る。 In a 100 ml three-necked reactor equipped with a dropping funnel and a three-way cock, 2.00 g of benzimidazole (substantially 1.96 g, 16.6 mmol because it is a 98% product) and 5.5 ml of methanol are charged and stirred at room temperature. 6.98 g of 35% tetraethylammonium hydroxide solution (2.44 g, 16.6 mmol because it is a 35% product) is dropped from the dropping funnel. Thereafter, the dropping funnel is washed with methanol (2.8 ml), and the methanol solution is also dropped into the reaction system. After stirring at room temperature for 1 day, the solvent of the reaction mixture is distilled off and dried under reduced pressure (60 ° C. 17 hr) to obtain 3.72 g of a white solid.
　Ｎ２Ｂｎの吸収状態融点（Ｔｍａｄ）と、二酸化炭素を脱離した状態でのイオン液体の融点または分解温度（Ｔｍｄｅ）は、次の様にして測定された。 The absorption state melting point (Tmad) of N2Bn and the melting point or decomposition temperature (Tmde) of the ionic liquid in a state where carbon dioxide was desorbed were measured as follows.
（Ｔｍａｄ）
　フラスコに約１ｇのＮ２Ｂｎを入れて、フラスコ内を０．１ｋＰａ以下の真空状態とした後、１４ｋＰａの二酸化炭素ガスを供給した状態で、フラスコを室温から１５０℃まで０．５℃／ｍｉｎの速度で昇温した。目視でＮ２Ｂｎを観察し、Ｎ２Ｂｎが液化して約半量が透明化した時点の温度をＴｍａｄとした。Ｎ２ＢｎのＴｍａｄは５５℃と測定された。 (Tmad)
About 1 g of N2Bn was put into the flask, the inside of the flask was evacuated to 0.1 kPa or less, and then the flask was heated from room temperature to 150 ° C. at a rate of 0.5 ° C./min with 14 kPa of carbon dioxide gas supplied. The temperature was raised. N2Bn was visually observed, and the temperature at which N2Bn was liquefied and about half was transparent was defined as Tmad. The Tmad of N2Bn was measured to be 55 ° C.
（Ｔｍｄｅ）
　フラスコに約１ｇのＮ２Ｂｎを入れて、フラスコ内を０．１ｋＰａ以下の真空状態とした後、１０１ｋＰａの窒素ガスを供給した状態で、フラスコを室温から１５０℃まで０．５℃／ｍｉｎの速度で昇温した。目視でＮ２Ｂｎを観察したところ、１５０℃に到達するまでＮ２Ｂｎは液化せず、１５０℃でＮ２Ｂｎは分解した。よってＮ２ＢｎのＴｍｄｅ（分解温度）は１５０℃と測定された。 (Tmde)
About 1 g of N2Bn was put in the flask, and the inside of the flask was evacuated to 0.1 kPa or less. Then, with the supply of 101 kPa of nitrogen gas, the flask was heated from room temperature to 150 ° C. at a rate of 0.5 ° C./min. The temperature rose. When N2Bn was visually observed, N2Bn was not liquefied until it reached 150 ° C, and N2Bn decomposed at 150 ° C. Therefore, the Tmde (decomposition temperature) of N2Bn was measured to be 150 ° C.
　テトラエチルアンモニウムイミダゾリド（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍｉｍｉｄａｚｏｌｉｄｅ、Ｎ２Ｉｍ）は、カチオン：テトラエチルアンモニウム（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ、Ｎ２２２２）と、アニオン：イミダゾール（ｉｍｉｄａｚｏｌｅ、Ｉｍ）との塩であり、以下の化２で表されるイオン液体である。 Tetraethylammonium imidazolide (tetraethylammoniumimidazolide, N2Im) is cationic: tetraethylammonium (tetraethylammonium, N 2222) and an anion: a salt with imidazole (imidazole, Im), it is an ionic liquid represented by the following Formula 2.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　Ｎ２Ｉｍは、テトラエチルアンモニウムヒドロキシドとイミダゾールとを反応させて合成することができる。具体的には、以下の手順で合成することができる。 N2Im can be synthesized by reacting tetraethylammonium hydroxide and imidazole. Specifically, it can be synthesized by the following procedure.
　滴下漏斗と三方コックを装着した１００ｍｌ三つ口反応器にイミダゾール０．８２ｇ（９８％品であるため実質、０．８０ｇ，１１．８ｍｍｏｌ）、メタノール４．０ｍｌを仕込み、室温撹拌する。滴下漏斗より３５％テトラエチルアンモニウムヒドロキシド溶液４．９４ｇ（３５％品であるため１．７３ｇ、１１．８ｍｍｏｌ）を滴下する。その後、滴下漏斗をメタノール（２．０ｍｌ）で洗い、そのメタノール溶液も反応系中に滴下する。室温で１日撹拌したのち、この反応混合液の溶媒を溜去して減圧乾燥（６０℃１７ｈｒ）することで白色固体１．４５ｇを得る。 A 100 ml three-necked reactor equipped with a dropping funnel and a three-way cock is charged with 0.82 g of imidazole (because it is a 98% product, 0.80 g, 11.8 mmol) and 4.0 ml of methanol, and stirred at room temperature. 4.94 g of 35% tetraethylammonium hydroxide solution (1.73 g, 11.8 mmol because it is a 35% product) is dropped from the dropping funnel. Thereafter, the dropping funnel is washed with methanol (2.0 ml), and the methanol solution is also dropped into the reaction system. After stirring at room temperature for 1 day, the solvent of this reaction mixture is distilled off and dried under reduced pressure (60 ° C. 17 hr) to obtain 1.45 g of a white solid.
　Ｎ２Ｉｍの吸収状態融点（Ｔｍａｄ）と、二酸化炭素を脱離した状態でのイオン液体の融点または分解温度（Ｔｍｄｅ）は、Ｎ２Ｂｎと同様に、次の様にして測定された。 The absorption melting point (Tmad) of N2Im and the melting point or decomposition temperature (Tmde) of the ionic liquid in a state where carbon dioxide was desorbed were measured as follows, similarly to N2Bn.
（Ｔｍａｄ）
　フラスコに約１ｇのＮ２Ｉｍを入れて、フラスコ内を０．１ｋＰａ以下の真空状態とした後、１４ｋＰａの二酸化炭素ガスを供給した状態で、フラスコを室温から１５０℃まで０．５℃／ｍｉｎの速度で昇温した。目視でＮ２Ｉｍを観察し、Ｎ２Ｉｍが液化して約半量が透明化した時点の温度をＴｍａｄとした。Ｎ２ＩｍのＴｍａｄは７０℃と測定された。 (Tmad)
About 1 g of N2Im was put into the flask, the inside of the flask was evacuated to 0.1 kPa or less, and then the flask was supplied at a rate of 0.5 ° C./min from room temperature to 150 ° C. while supplying 14 kPa of carbon dioxide gas. The temperature was raised. N2Im was visually observed, and the temperature at the time when N2Im liquefied and about half of the amount became transparent was defined as Tmad. The Tmad of N2Im was measured as 70 ° C.
（Ｔｍｄｅ）
　フラスコに約１ｇのＮ２Ｉｍを入れて、フラスコ内を０．１ｋＰａ以下の真空状態とした後、１０１ｋＰａの窒素ガスを供給した状態で、フラスコを室温から１５０℃まで０．５℃／ｍｉｎの速度で昇温した。目視でＮ２Ｉｍを観察したところ、１２５℃に到達するまでＮ２Ｉｍは液化せず、１２５℃でＮ２Ｉｍは分解した。よってＮ２ＩｍのＴｍｄｅ（分解温度）は１２５℃と測定された。 (Tmde)
About 1 g of N2Im was put into the flask, and after the inside of the flask was evacuated to 0.1 kPa or less, 101 kPa of nitrogen gas was supplied and the flask was heated from room temperature to 150 ° C. at a rate of 0.5 ° C./min. The temperature rose. When N2Im was visually observed, N2Im was not liquefied until it reached 125 ° C, and N2Im decomposed at 125 ° C. Therefore, the Tmde (decomposition temperature) of N2Im was measured to be 125 ° C.
　テトラブチルアンモニウムカルバゾリド（ｔｅｔｒａｂｕｔｈｙｌａｍｍｏｎｉｕｍｃａｒｂａｚｏｌｉｄｅ、Ｎ４Ｃｚ）は、カチオン：テトラブチルアンモニウム（ｔｅｔｒａｂｕｔｈｙｌａｍｍｏｎｉｕｍ、Ｎ４４４４）と、アニオン：カルバゾール（ｃａｒｂａｚｏｌｅ、Ｃｚ）との塩であり、以下の化３で表されるイオン液体である。 Tetrabutylammonium carbazolyl de (tetrabuthylammoniumcarbazolide, N4Cz) is cationic: tetrabutylammonium (tetrabuthylammonium, N 4444) and an anion: carbazole (carbazole, Cz) is a salt with an ionic liquid represented by the following Formula 3 It is.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　Ｎ４Ｃｚは、テトラブチルアンモニウムヒドロキシドとカルバゾールとを反応させて合成することができる。具体的には、以下の手順で合成することができる。 N4Cz can be synthesized by reacting tetrabutylammonium hydroxide with carbazole. Specifically, it can be synthesized by the following procedure.
　滴下漏斗と三方コックを装着した１００ｍｌ三つ口反応器にカルバゾール０．６７ｇ（９６％品であるため実質、０．６４ｇ，３．８５ｍｍｏｌ）、ＴＨＦ５．０ｍｌを仕込み、室温撹拌する。滴下漏斗より１０％テトラブチルアンモニウムヒドロキシドメタノール溶液１０．００ｇ（１０％品であるため１．００ｇ、３．８５ｍｍｏｌ）を滴下する。その後、滴下漏斗をＴＨＦ（２．０ｍｌ）で洗い、そのＴＨＦ溶液も反応系中に滴下する。室温で２日撹拌した後、この反応混合液の溶媒を溜去して減圧乾燥（６０℃１７ｈｒ）することで黄色固体１．２６ｇを得る。 A 100 ml three-necked reactor equipped with a dropping funnel and a three-way cock is charged with 0.67 g of carbazole (because it is a 96% product, 0.64 g, 3.85 mmol) and 5.0 ml of THF, and stirred at room temperature. From a dropping funnel, 10.00 g of a 10% tetrabutylammonium hydroxide methanol solution (1.00 g, 3.85 mmol because it is a 10% product) is dropped. Thereafter, the dropping funnel is washed with THF (2.0 ml), and the THF solution is also dropped into the reaction system. After stirring at room temperature for 2 days, the solvent of this reaction mixture is distilled off and dried under reduced pressure (60 ° C., 17 hr) to obtain 1.26 g of a yellow solid.
　Ｎ４Ｃｚの吸収状態融点（Ｔｍａｄ）と、二酸化炭素を脱離した状態でのイオン液体の融点または分解温度（Ｔｍｄｅ）は、Ｎ２Ｂｎと同様に、次の様にして測定された。 The absorption melting point (Tmad) of N4Cz and the melting point or decomposition temperature (Tmde) of the ionic liquid in a state where carbon dioxide was desorbed were measured as follows in the same manner as N2Bn.
（Ｔｍａｄ）
　フラスコに約１ｇのＮ４Ｃｚを入れて、フラスコ内を０．１ｋＰａ以下の真空状態とした後、１４ｋＰａの二酸化炭素ガスを供給した状態で、フラスコを室温から１５０℃まで０．５℃／ｍｉｎの速度で昇温した。目視でＮ４Ｃｚを観察し、Ｎ４Ｃｚが液化して約半量が透明化した時点の温度をＴｍａｄとした。Ｎ４ＣｚのＴｍａｄは１００℃と測定された。 (Tmad)
About 1 g of N4Cz was put into the flask, the inside of the flask was evacuated to 0.1 kPa or less, and then the flask was supplied at a rate of 0.5 ° C./min from room temperature to 150 ° C. while supplying 14 kPa of carbon dioxide gas. The temperature was raised. N4Cz was visually observed, and the temperature at which N4Cz was liquefied and about half was transparent was defined as Tmad. The N4Cz Tmad was measured at 100 ° C.
（Ｔｍｄｅ）
　フラスコに約１ｇのＮ４Ｃｚを入れて、フラスコ内を０．１ｋＰａ以下の真空状態とした後、１０１ｋＰａの窒素ガスを供給した状態で、フラスコを室温から１５０℃まで０．５℃／ｍｉｎの速度で昇温した。目視でＮ４Ｃｚを観察した。１５０℃に到達するまで、Ｎ４Ｃｚは溶融および分解しなかった。よってＮ４ＣｚのＴｍｄｅ（分解温度）は１５０℃以上と測定された。 (Tmde)
About 1 g of N4Cz was put into the flask, and the inside of the flask was evacuated to 0.1 kPa or less. Then, with the supply of 101 kPa of nitrogen gas, the flask was heated from room temperature to 150 ° C. at a rate of 0.5 ° C./min. The temperature rose. N4Cz was visually observed. N4Cz did not melt and decompose until 150 ° C was reached. Therefore, the Tmde (decomposition temperature) of N4Cz was measured to be 150 ° C. or higher.
　上述したイオン液体を含む二酸化炭素回収用組成物は、液体の状態で二酸化炭素の回収に用いることが可能である。また、イオン液体を含む二酸化炭素回収用組成物を、担体に担持させた状態で二酸化炭素の回収に用いるとより好適である。適用可能な担体としては、例えば、カプセルや多孔質無機粒子等が挙げられる。 The above-mentioned composition for recovering carbon dioxide containing an ionic liquid can be used for recovering carbon dioxide in a liquid state. Further, it is more preferable to use a carbon dioxide recovery composition containing an ionic liquid for carbon dioxide recovery in a state of being supported on a carrier. Examples of applicable carriers include capsules and porous inorganic particles.
　カプセルとしては、例えば、コアシェル型カプセルや、海島構造型カプセルなど、ガス吸収材料が表面に露出しないよう構成されるものが好ましい。即ち、ガス吸収材料が内側に配置され、ガス吸収材料の外側が膜や外殻で覆われる状態となる。 As the capsule, for example, a core-shell type capsule or a sea-island structure type capsule that is configured so that the gas absorbing material is not exposed to the surface is preferable. That is, the gas absorbing material is disposed on the inner side, and the outer side of the gas absorbing material is covered with a film or an outer shell.
　多孔質無機粒子としては、表面まで貫通しているが、孔径が小さくてガス吸収材料が液化しても溶出しないものが好ましい。 The porous inorganic particles are preferably those that penetrate to the surface but do not elute even when the gas absorbing material is liquefied because the pore diameter is small.
　多孔質無機粒子を形成する無機物としては、例えば、ケイ酸塩、リン酸塩、酸化物等が挙げられる。ケイ酸塩としては、例えばケイ酸カルシウム、ケイ酸バリウム、ケイ酸マグネシウム、ゼオライト等が挙げられる。リン酸塩としては、例えば、リン酸カルシウム、リン酸バリウム、リン酸マグネシウム、リン酸ジルコニウム、アパタイト等が挙げられる。酸化物としては、例えば、二酸化ケイ素や一酸化ケイ素などの酸化ケイ素、アルミナ等が挙げられる。好ましくは酸化物であり、より好ましくは酸化ケイ素であり、さらにより好ましくは二酸化ケイ素である。 Examples of inorganic substances forming the porous inorganic particles include silicates, phosphates, oxides, and the like. Examples of the silicate include calcium silicate, barium silicate, magnesium silicate, and zeolite. Examples of the phosphate include calcium phosphate, barium phosphate, magnesium phosphate, zirconium phosphate, and apatite. Examples of the oxide include silicon oxide such as silicon dioxide and silicon monoxide, and alumina. Preferred is an oxide, more preferred is silicon oxide, and even more preferred is silicon dioxide.
　次に本実施形態に係る二酸化炭素回収方法と、二酸化炭素回収方法が行われる設備の一例としての温度スイング吸着装置１について図１を参照して説明する。 Next, a carbon dioxide recovery method according to this embodiment and a temperature swing adsorption device 1 as an example of equipment in which the carbon dioxide recovery method is performed will be described with reference to FIG.
　本実施形態における温度スイング吸着装置１は、第１吸収槽２、第２吸収槽３、蒸気供給ライン４、処理ガス供給ライン５、二酸化炭素回収ライン６、排気ライン７、及びブロワー８を備えて構成されており、ガス吸収材９が、第１吸収槽２及び第２吸収槽３のそれぞれの内部に充填されている。ガス吸収材９は、上述の二酸化炭素回収用組成物を担体に担持させたものである。 The temperature swing adsorption device 1 in this embodiment includes a first absorption tank 2, a second absorption tank 3, a steam supply line 4, a process gas supply line 5, a carbon dioxide recovery line 6, an exhaust line 7, and a blower 8. The gas absorbing material 9 is filled in each of the first absorption tank 2 and the second absorption tank 3. The gas absorbent 9 is obtained by supporting the above-described carbon dioxide recovery composition on a carrier.
　温度スイング吸着装置１に適用可能な処理ガスとしては、例えば、火力発電所、製鉄所高炉、自動車等から排出される産業処理ガスが挙げられる。 As the processing gas applicable to the temperature swing adsorption device 1, for example, industrial processing gas discharged from a thermal power plant, a steelworks blast furnace, an automobile and the like can be mentioned.
　処理ガス供給ライン５を介して処理ガスを第１吸収槽２に所定時間供給して、処理ガス中に含まれる二酸化炭素をガス吸収材９に吸収させる（吸収工程）。残りのガス成分は排気ライン７を介して排出される。 The processing gas is supplied to the first absorption tank 2 through the processing gas supply line 5 for a predetermined time, and the gas absorbent 9 absorbs carbon dioxide contained in the processing gas (absorption process). The remaining gas components are discharged via the exhaust line 7.
　所定時間経過後、処理ガス供給ライン５を切り替えて、処理ガスを第２吸収槽３に所定時間供給すると共に、蒸気供給ライン４を介して高温の蒸気を第１吸収槽２に所定時間供給して加熱し、二酸化炭素を脱離させてガス吸収材９を再生させる（再生工程）。脱離した二酸化炭素は二酸化炭素回収ライン６を介して回収される。 After a predetermined time has elapsed, the processing gas supply line 5 is switched to supply the processing gas to the second absorption tank 3 for a predetermined time, and high-temperature steam is supplied to the first absorption tank 2 through the vapor supply line 4 for a predetermined time. Then, carbon dioxide is desorbed to regenerate the gas absorbent 9 (regeneration step). The desorbed carbon dioxide is recovered via the carbon dioxide recovery line 6.
　さらに所定時間経過後、処理ガス供給ライン５を切り替えて、処理ガスを再び第１吸収槽２に所定時間供給すると共に、蒸気供給ライン４を切り替えて、蒸気を第２吸収槽３に所定時間供給して加熱し、二酸化炭素を脱離させてガス吸収材９を再生させる。 Further, after a predetermined time has elapsed, the processing gas supply line 5 is switched to supply the processing gas to the first absorption tank 2 again for a predetermined time, and the steam supply line 4 is switched to supply steam to the second absorption tank 3 for a predetermined time. And heated to desorb carbon dioxide to regenerate the gas absorbent 9.
　即ち、第１吸収槽２及び第２吸収槽３のいずれか一方において、処理ガスと接触して二酸化炭素をガス吸収材９に吸収させる吸収工程が運転され、他方において、加熱により二酸化炭素を脱離させてガス吸収材９を再生させる再生工程が運転され、所定時間ごとに切り替わるように構成されている。従って、処理ガス中の二酸化炭素を連続的に分離・回収することができる。 That is, in either one of the first absorption tank 2 and the second absorption tank 3, an absorption process is performed in which the gas absorbent 9 is brought into contact with the processing gas and carbon dioxide is absorbed. On the other hand, the carbon dioxide is removed by heating. The regeneration step of regenerating the gas absorbing material 9 is operated, and is configured to switch every predetermined time. Therefore, carbon dioxide in the processing gas can be continuously separated and recovered.
　ここで上述の吸収工程および再生工程におけるイオン液体の相変化について、イオン液体としてテトラエチルアンモニウムベンゾイミダゾリド（Ｎ２Ｂｎ）を使用する場合を例として説明する。 Here, the phase change of the ionic liquid in the absorption process and the regeneration process described above will be described by taking as an example the case of using tetraethylammonium benzimidazolide (N2Bn) as the ionic liquid.
　本実施形態の吸収工程は、二酸化炭素を含有する処理ガスを二酸化炭素回収用組成物に接触させて、二酸化炭素をイオン液体に吸収させる工程であり、吸収工程が行われる吸収工程温度Ｔａｄは吸収状態融点よりも高い。具体的には処理ガスの温度をＮ２Ｂｎの吸収状態融点Ｔｍａｄ＝５５℃よりも高く、例えば７０℃として、吸収工程を行う。二酸化炭素を吸収する前のＮ２Ｂｎは、Ｔｍｄｅ（二酸化炭素を脱離した状態でのイオン液体の融点または分解温度）＝１５０℃であることから、固体である。７０℃の処理ガスと接触して二酸化炭素を吸収すると、Ｎ２Ｂｎの融点はＴｍａｄ＝５５℃まで下がり、吸収工程温度Ｔａｄよりも低くなるから、Ｎ２Ｂｎは融解する。このときＮ２Ｂｎは融解熱を放出する。 The absorption process of the present embodiment is a process in which a treatment gas containing carbon dioxide is brought into contact with the carbon dioxide recovery composition and carbon dioxide is absorbed into the ionic liquid, and the absorption process temperature Tad at which the absorption process is performed is absorbed. It is higher than the state melting point. Specifically, the absorption process is performed with the temperature of the processing gas being higher than the absorption state melting point Tmad of N2Bn = 55 ° C., for example, 70 ° C. Since N2Bn before absorbing carbon dioxide is Tmde (melting point or decomposition temperature of the ionic liquid in a state where carbon dioxide is desorbed) = 150 ° C., it is a solid. When carbon dioxide is absorbed in contact with a processing gas at 70 ° C., the melting point of N 2 Bn falls to Tmad = 55 ° C. and becomes lower than the absorption process temperature Tad, so that N 2 Bn melts. At this time, N2Bn releases heat of fusion.
　本実施形態の再生工程は、二酸化炭素回収用組成物を加熱して二酸化炭素を脱離させる工程であり、吸収工程の次に行われ、再生工程が行われる再生工程温度Ｔｄｅは、吸収工程温度Ｔａｄよりも高く、イオン液体の融点および分解温度（Ｔｍｄｅ）よりも低い。具体的には蒸気の温度（再生工程温度）をＴａｄ＝７０℃よりも高く、かつＮ２ＢｎのＴｍｄｅ＝１５０℃よりも低くして行う。例えば再生工程温度Ｔｄｅ＝１２０℃として再生工程を行う。二酸化炭素を脱離する前のＮ２Ｂｎは、Ｔｍａｄ＝５５℃であることから、液体である。１２０℃の蒸気と接触して二酸化炭素を脱離すると、Ｎ２Ｂｎの融点は上昇してＴｍｄｅ＝１５０℃以上となり、再生工程温度Ｔｄｅ＝１２０℃よりも高くなるから、Ｎ２Ｂｎは凝固する。このときＮ２Ｂｎは凝固熱を放出する。 The regeneration step of the present embodiment is a step of heating the carbon dioxide recovery composition to desorb carbon dioxide. The regeneration step temperature Tde performed after the absorption step and performing the regeneration step is the absorption step temperature. It is higher than Tad and lower than the melting point and decomposition temperature (Tmde) of the ionic liquid. Specifically, the vapor temperature (regeneration process temperature) is higher than Tad = 70 ° C. and lower than Tmde = 150 ° C. of N 2 Bn. For example, the regeneration process is performed at a regeneration process temperature Tde = 120 ° C. Since N2Bn before desorbing carbon dioxide is Tmad = 55 ° C., it is a liquid. When carbon dioxide is desorbed by contact with steam at 120 ° C., the melting point of N 2 Bn rises to Tmde = 150 ° C. or higher and becomes higher than the regeneration process temperature Tde = 120 ° C., so that N 2 Bn is solidified. At this time, N2Bn releases heat of solidification.
　イオン液体としてテトラエチルアンモニウムイミダゾリド（Ｎ２Ｉｍ）を使用する場合、Ｎ２ＩｍのＴｍａｄ＝７０℃、Ｔｍｄｅ＝１２５℃であることから、吸収工程を、吸収工程温度ＴａｄがＴｍａｄ＝７０℃より高い状態、例えば８０℃で行う。再生工程を、再生工程温度ＴｄｅがＴａｄ＝８０℃より高くＴｍｄｅ＝１２５℃より低い状態、例えば１００℃で行う。 When tetraethylammonium imidazolide (N2Im) is used as the ionic liquid, since the Tmad of N2Im is 70 ° C. and Tmde = 125 ° C., the absorption process is performed in a state where the absorption process temperature Tad is higher than Tmad = 70 ° C., for example, 80 Perform at ℃. The regeneration process is performed in a state where the regeneration process temperature Tde is higher than Tad = 80 ° C. and lower than Tmde = 125 ° C., for example, 100 ° C.
　イオン液体としてテトラブチルアンモニウムカルバゾリド（Ｎ４Ｃｚ）を使用する場合、Ｎ４ＣｚのＴｍａｄ＝１００℃、Ｔｍｄｅ＝１５０℃であることから、吸収工程を、吸収工程温度ＴａｄがＴｍａｄ＝１００℃より高い状態、例えば１１０℃で行う。再生工程を、再生工程温度ＴｄｅがＴａｄ＝１１０℃より高くＴｍｄｅ＝１５０℃より低い状態、例えば１３０℃で行う。 When tetrabutylammonium carbazolide (N4Cz) is used as the ionic liquid, since the N4Cz Tmad = 100 ° C. and Tmde = 150 ° C., the absorption process is performed in a state where the absorption process temperature Tad is higher than Tmad = 100 ° C. For example, it is performed at 110 ° C. The regeneration process is performed in a state where the regeneration process temperature Tde is higher than Tad = 110 ° C. and lower than Tmde = 150 ° C., for example, 130 ° C.
（他の実施形態）
（１）上述の温度スイング吸着装置１において、第１吸収槽２、及び第２吸収槽３の２つの吸収槽を使用しているが、この構成に限定されるものではなく、さらにより多くの吸収槽を設置してもよい。 (Other embodiments)
(1) In the above-described temperature swing adsorption device 1, two absorption tanks, the first absorption tank 2 and the second absorption tank 3, are used, but the present invention is not limited to this configuration, and even more An absorption tank may be installed.
（２）上述の温度スイング吸着装置１が、さらに凝縮器を備えるように構成してもよい。回収された二酸化炭素は水分を含むため、凝縮器によって水分を除去して、二酸化炭素のみを分離・回収することができる。尚、取り除かれた水分は、蒸気として再利用することができる。 (2) The above-described temperature swing adsorption device 1 may further include a condenser. Since the recovered carbon dioxide contains moisture, only the carbon dioxide can be separated and recovered by removing the moisture with a condenser. The removed water can be reused as steam.
（３）上述の温度スイング吸着装置に対して、必要に応じて圧力スイング法を組み合わせてもよいし、あるいは温度スイング法に替えて圧力スイング法のみを採用するようにしてもよい。圧力スイング法では、再生工程中に、二酸化炭素回収ラインをポンプで引いて吸収槽内を減圧気味にするため、ガス吸収材の再生を促すことができる。 (3) The above-described temperature swing adsorption device may be combined with a pressure swing method as necessary, or only the pressure swing method may be adopted instead of the temperature swing method. In the pressure swing method, during the regeneration process, the carbon dioxide recovery line is pulled by a pump to make the inside of the absorption tank have a reduced pressure, so that regeneration of the gas absorbent can be promoted.
（４）上述の温度スイング吸着装置では、ガス吸収材９は第１吸収槽２および第２吸収槽３に充填され、ガス吸収材９が移動しない状態で二酸化炭素の回収が行われる。そして第１吸収槽２および第２吸収槽３では、吸収工程と再生工程とが交互に行われる。これを改変し、一方の槽（吸収塔）で吸収工程を行わせ、他方の槽（再生塔）で再生工程を行わせ、ガス吸収材９（イオン液体を担持した担体）を２つの槽に循環させてもよい。具体的には、吸収塔でガス吸収材９が処理ガスと接触して、イオン液体が二酸化炭素を吸収し、融解する。そしてガス吸収材９が再生塔に移され、高温の蒸気により加熱されて、イオン液体が二酸化炭素を放出し、凝固する。そしてガス吸収材９が再び吸収塔に移される。この場合でも、温度スイング法に加えて圧力スイング法を組み合わせてもよいし、あるいは温度スイング法に替えて圧力スイング法のみを採用するようにしてもよい。 (4) In the above-described temperature swing adsorption device, the gas absorbent 9 is filled in the first absorbent tank 2 and the second absorbent tank 3, and carbon dioxide is recovered without the gas absorbent 9 moving. And in the 1st absorption tank 2 and the 2nd absorption tank 3, an absorption process and a regeneration process are performed by turns. By modifying this, the absorption process is performed in one tank (absorption tower), the regeneration process is performed in the other tank (regeneration tower), and the gas absorbent 9 (carrier carrying ionic liquid) is put into two tanks. It may be circulated. Specifically, the gas absorbent 9 comes into contact with the processing gas in the absorption tower, and the ionic liquid absorbs carbon dioxide and melts. Then, the gas absorbent 9 is transferred to the regeneration tower and heated by high-temperature steam, and the ionic liquid releases carbon dioxide and solidifies. And the gas absorption material 9 is moved to an absorption tower again. Even in this case, the pressure swing method may be combined with the temperature swing method, or only the pressure swing method may be adopted instead of the temperature swing method.
（５）上述の実施形態では、イオン液体を担体に担持させて固体として取り扱う例を説明したが、イオン液体を溶解させない溶媒を用いて、その液中にイオン液体をスラリー状に分散させ、全体として液体の状態のガス吸収材９を構成してもよい。そして液体状態のガス吸収剤９を、上述の吸収塔・再生塔に循環させてもよい。 (5) In the above-described embodiment, an example in which an ionic liquid is supported on a carrier and handled as a solid has been described. However, a solvent that does not dissolve the ionic liquid is used to disperse the ionic liquid in a slurry and the whole The gas absorbent material 9 in a liquid state may be configured as follows. Then, the gas absorbent 9 in the liquid state may be circulated to the absorption tower / regeneration tower described above.
　なお上述の実施形態（他の実施形態を含む、以下同じ）で開示される構成は、矛盾が生じない限り、他の実施形態で開示される構成と組み合わせて適用することが可能であり、また、本明細書において開示された実施形態は例示であって、本発明の実施形態はこれに限定されず、本発明の目的を逸脱しない範囲内で適宜改変することが可能である。 Note that the configurations disclosed in the above-described embodiments (including the other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in the other embodiments unless there is a contradiction. The embodiments disclosed in this specification are exemplifications, and the embodiments of the present invention are not limited thereto, and can be appropriately modified without departing from the object of the present invention.
１　　　　：温度スイング吸着装置
２　　　　：第１吸収槽
３　　　　：第２吸収槽
４　　　　：蒸気供給ライン
５　　　　：処理ガス供給ライン
６　　　　：二酸化炭素回収ライン
７　　　　：排気ライン
８　　　　：ブロワー
９　　　　：ガス吸収材 1: Temperature swing adsorption device 2: 1st absorption tank 3: 2nd absorption tank 4: Steam supply line 5: Process gas supply line 6: Carbon dioxide recovery line 7: Exhaust line 8: Blower 9: Gas absorber

Claims (6)

  1. 　イオン液体を含有する二酸化炭素回収用組成物であって、二酸化炭素を吸収した状態での前記イオン液体の融点である吸収状態融点が５０℃以上１１０℃以下であり、二酸化炭素を脱離した状態での前記イオン液体の融点または分解温度が前記吸収状態融点よりも高い、二酸化炭素回収用組成物。 A composition for recovering carbon dioxide containing an ionic liquid, wherein the absorption state melting point of the ionic liquid in a state of absorbing carbon dioxide is 50 ° C. or higher and 110 ° C. or lower and carbon dioxide is desorbed The composition for carbon dioxide recovery, wherein the melting point or decomposition temperature of the ionic liquid is higher than the absorption state melting point.
  2. 　前記イオン液体が、テトラエチルアンモニウムベンゾイミダゾリドを含む請求項１に記載の二酸化炭素回収用組成物。 The composition for carbon dioxide recovery according to claim 1, wherein the ionic liquid contains tetraethylammonium benzimidazolide.
  3. 　前記イオン液体が、テトラエチルアンモニウムイミダゾリドを含む請求項１に記載の二酸化炭素回収用組成物。 The composition for carbon dioxide recovery according to claim 1, wherein the ionic liquid contains tetraethylammonium imidazolide.
  4. 　前記イオン液体が、テトラブチルアンモニウムカルバゾリドを含む請求項１に記載の二酸化炭素回収用組成物。 The composition for carbon dioxide recovery according to claim 1, wherein the ionic liquid contains tetrabutylammonium carbazolide.
  5. 　吸収工程を有する二酸化炭素回収方法であって、
    　前記吸収工程は、二酸化炭素を含有する処理ガスをイオン液体を含有する二酸化炭素回収用組成物に接触させて、二酸化炭素を前記イオン液体に吸収させる工程であり、
    　二酸化炭素を吸収した状態での前記イオン液体の融点である吸収状態融点が５０℃以上１１０℃以下であり、二酸化炭素を脱離した状態での前記イオン液体の融点または分解温度が前記吸収状態融点よりも高く、
    　前記吸収工程が行われる吸収工程温度は前記吸収状態融点よりも高い、二酸化炭素回収方法。     A carbon dioxide recovery method having an absorption step,
    The absorption step is a step in which a treatment gas containing carbon dioxide is brought into contact with a carbon dioxide recovery composition containing an ionic liquid to absorb carbon dioxide into the ionic liquid;
    The absorption state melting point, which is the melting point of the ionic liquid in a state of absorbing carbon dioxide, is 50 ° C. or more and 110 ° C. or less, and the melting point or decomposition temperature of the ionic liquid in the state of removing carbon dioxide is the absorption state melting point. Higher than
    The carbon dioxide recovery method, wherein the absorption process temperature at which the absorption process is performed is higher than the absorption state melting point.
  6. 　再生工程を有し、
    　前記再生工程は、前記二酸化炭素回収用組成物を加熱して二酸化炭素を脱離させる工程であり、前記吸収工程の次に行われ、
    　前記再生工程が行われる再生工程温度は、前記吸収工程温度よりも高く、前記イオン液体の融点および分解温度よりも低い、請求項５に記載の二酸化炭素回収方法。     Has a regeneration process,
    The regeneration step is a step of heating the carbon dioxide recovery composition to desorb carbon dioxide, and is performed after the absorption step,
    The carbon dioxide recovery method according to claim 5, wherein a regeneration process temperature at which the regeneration process is performed is higher than the absorption process temperature and lower than a melting point and a decomposition temperature of the ionic liquid.
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WO2015069799A1 (en) * 2013-11-05 2015-05-14 University Of Notre Dame Du Lac Carbon dioxide capture using phase change ionic liquids
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