WO2021215265A1

WO2021215265A1 - Carbon dioxide absorbing material, carbon dioxide absorbing material production method, carbon dioxide separation body and carbon dioxide separation and recovery device

Info

Publication number: WO2021215265A1
Application number: PCT/JP2021/014974
Authority: WO
Inventors: 北村　武昭
Original assignee: 株式会社Ａｃｒ
Priority date: 2020-04-24
Filing date: 2021-04-09
Publication date: 2021-10-28
Also published as: JPWO2021215265A1; JP7333674B2

Abstract

The invention provides a carbon dioxide absorbing material in solid form, capable of separating and absorbing carbon dioxide from a gas containing carbon dioxide, and recovering the carbon dioxide efficiently and in an energy-saving manner, at a vacuum pressure that is only near ordinary pressure. The invention also provides a carbon dioxide absorbing material production method, a carbon dioxide separation body using the carbon dioxide absorbing material, and a carbon dioxide separation recovery device.　This carbon dioxide absorbing material is characterized by comprising an organopolysiloxane containing secondary amines, which is represented by general formula [I] and has a three-dimensional structure. [Chem 1] [I] (SiO₂·SiO·6CH₂)n(NH)x(2CH₂)x-1 (in the formula, n = an integer of 10 or greater, and X = integer of 1 to 10.)

Description

Carbon dioxide absorber, manufacturing method of carbon dioxide absorber, carbon dioxide separator and carbon dioxide separation and recovery device

The present invention relates to a carbon dioxide absorbent and a method for producing a carbon dioxide absorbent, which adsorbs and separates carbon dioxide from the atmosphere at normal temperature and pressure, and recovers or supplies carbon dioxide under vacuum pressure. Further, the present invention relates to a carbon dioxide separator and a carbon dioxide separation / recovery device that separates, recovers or supplies carbon dioxide with energy saving.

In recent years, the frequent occurrence of climate change and disasters, which are thought to be caused by global warming, has had a great impact on agricultural production, living environment, energy consumption, etc. Attention is being paid to carbon dioxide in the atmosphere as a causative substance of global warming, and as its source, iron oxide is used in coke, a thermal power plant that uses coal gasification gas (IGCC), oil, natural gas, etc. as fuel. Blast furnaces at steel mills to reduce, converters at steel mills that burn carbon in iron iron to make steel, boilers at various factories, kilns at cement factories, etc., and gasoline, heavy oil, light oil, etc. are used as fuel. There are transportation equipment such as automobiles, ships, and aircraft. Of these, equipment other than transportation equipment is fixed equipment, so it is expected to be equipment that makes it easy to take measures to reduce carbon dioxide emissions, and separates carbon dioxide in the exhaust gas emitted from these equipment. The method of recovery is under study.

In addition to this, in a closed space such as a submersible research vehicle or a space station, in order to release carbon dioxide emitted by human breathing or energy conversion of equipment to the outside of the closed space, consideration is given to separating and recovering carbon dioxide. It is also done.

Furthermore, plants promote photosynthesis by absorbing carbon dioxide as they grow. It is known that the growth rate of plants is increased by promoting photosynthesis. By absorbing carbon dioxide from the stomata of the leaves, it promotes photosynthesis, has a taste of vegetables, flowers and fruit trees, has a long shelf life after harvesting, has a great effect on color gloss and enlargement, and has a great effect on vegetables, flowers, Fruit trees can be produced with higher quality.

In farms that produce fruit trees, flowers and vegetables by house cultivation or indoor cultivation, carbon dioxide gas is given to plants using artificial meteorological equipment, gas cylinders, door rai ice and carbon dioxide generators.

However, the period requiring carbon dioxide is long, from the growing period to the late flowering period and the harvesting period, and in large-scale house cultivation and indoor cultivation, it is replaced with artificial meteorological equipment, gas cylinders, door rai ice and carbon dioxide generators. The problem was that the frequency was high and the cost was high.

Absorbents and methods for recovering or recycling exhaust gas and carbon dioxide in the atmosphere have been studied for a long time, and research is still ongoing to solve the problem of recovering carbon dioxide with less energy and low cost.

For example, Patent Document 1 discloses a solid carbon dioxide absorber in which mesoporous silica such as SBA-15 having high thermal stability is used as a support and a silane coupling agent is chemically bonded to the surface thereof.

In Patent Document 1, the silane coupling agent is 3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- ( 2-Aminoethyl) -3-aminopropylmethyldimethoxysilane, (3-trimethoxysilylpropyl) diethylenetriamine, in which alcohol is formed at the end of the molecule to form silanol obtained by hydrolysis, and the support is silica and dehydrated. It is condensed and bonded. The other of the molecules consists of an organic alkyl chain with primary and / or secondary amino groups. The silane coupling agent cannot fill the entire pore volume of the mesoporous silica support, has a low density of amino groups that absorb carbon dioxide, and has a problem that the reaction point for absorption is not sufficient. Further, although 3-aminopropyltriethoxysilane APS (gel) alone is disclosed in Examples, the specific surface area is as ^{small as 2 m 2} / g, and the _{amount of CO 2} adsorbed in the absence of water is inferior.

Patent Document 2 discloses a solid carbon dioxide absorber supported on a support by using 2-isopropylaminoethanol alone or a mixture of piperazines.

Patent Document 3 discloses a carbon dioxide separating material containing a polyamine carrier in which a polyamine having at least two isopropyl groups on a nitrogen atom is supported on the support.

Patent Document 4 describes tertiary alkanolamines and tertiary alkylamines as catalysts such as bis (2,4-pentanenate) magnesium, bis (2,4-pentanezionate) cobalt, and bis (2,4-pentane). Dissolved in an aqueous solution containing (geonate) calcium, bis (2,4-pentanegeonate) zinc, bis (2,4-pentanegeonate) copper and bis [2- (2-benzoxazolyl) phenolate] zinc. Alternatively, a suspended liquid adsorbent or a solid adsorbent carried on a support is disclosed.

However, the desorption (recovery) speed is not sufficient in either case, and the current situation is that energy saving and low cost for practical use have not yet been reached.

Japanese Unexamined Patent Publication No. 2004-261670 Japanese Unexamined Patent Publication No. 2012-139622 Japanese Patent No. 6600457 Japanese Patent No. 6463186

The present invention is a method for producing a solid carbon dioxide absorber and a carbon dioxide absorber that can separate and absorb carbon dioxide in a gas containing carbon dioxide and recover carbon dioxide efficiently with energy saving only at a vacuum pressure close to normal pressure. An object of the present invention is to provide a carbon dioxide separator and a carbon dioxide separation / recovery apparatus using a carbon dioxide absorber.

The carbon dioxide absorbent provided by the first aspect of the present invention is to absorb and separate carbon dioxide from the atmosphere, normal temperature and pressure at the gas pressure of the source. The second aspect of the present invention is that the absorbed and separated carbon dioxide is separated and recovered by a VSA (Vacuum Swing Adsorption) method having a vacuum pressure of -80 kPaG to -101 kPaG (gauge pressure) at room temperature, and the separation and recovery energy is 1.0 GJ. The purpose is to make / t-CO ₂ equivalent and separation cost 1000 yen / t-CO _{2 equivalent.}

In

Patent Documents

1, 2, 3 and 4, primary, secondary and tertiary amine compounds are impregnated into a porous support to form a solid carbon dioxide absorber, and these amine compounds and carbon dioxide are used. We propose the desorption (recovery) of carbon dioxide by absorbing (separating) carbon dioxide by generating carbamate and / or bicarbonate ions from the reaction and causing the reverse reaction.

Therefore, the reaction between the primary, secondary and tertiary amine compounds and carbon dioxide is shown below.

First, the carbon dioxide absorption process using an aqueous solution of a primary amine (R-NH ₂ ) is generally represented by the following formulas (a) to (c).

[Chemical 1]
_{(A) 2R-NH 2 +} CO 2 → R-NH 3 + + R-NH-COO -
_{(B) R-NH 2 +} CO 2 + H 2 O → R-NH 3 + + HCO 3 -
(C) R-NH-COO - + H 2 O → R-NH 2 + HCO 3 -

Next, the carbon dioxide absorption process using an aqueous solution of a secondary amine (R ₁ R _2- NH) is generally represented by the following formulas (d) to (f).

[Chemical 2]
_{_{(D) 2R 1 R 2 -NH}} + CO 2 → R 1 R 2 -NH 2 + + R 1 R 2 -N-COO -
(E) R ₁ R _2- NH + CO ₂ + _{_{_{H 2 O → R 1 R 2}}} -NH 2 + + HCO 3 -
_{_{(F) R 1 R 2 -N}} -COO - + H 2 O → R 1 R 2 -NH + HCO 3 -

Further, the carbon dioxide absorption process using an aqueous solution of a tertiary amine (R ₁ R ₂ R _3- N) is generally represented by the following formula (g).

[Chemical 3]
_{_{(G) R 1 R 2 R}} 3 -N + CO 2 + H 2 O → R 1 R 2 R 3 -NH + + HCO 3 -

The primary amine and the secondary amine _{react with 2 mol of amine and CO 2 as in} formulas (a) and (d) to produce carbamate and absorb _{CO 2.} When the CO ₂ gas contains water, it reacts as in the formulas (b), (c), formula (e), and formula (f) to generate hydrogen carbonate ions and absorb _{CO 2.}

On the other hand, in the tertiary amine, CO ₂ and water react as shown in the formula (g) to generate hydrogen carbonate ion and absorb _{CO 2.}

Absorption of CO ₂ is the sum of the heat of formation is an exothermic reaction, primary amines> secondary amine> larger in the order of tertiary amines, CO ₂ absorption rate is faster trend. On the contrary, the _{desorption (regeneration) of CO 2} is an endothermic reaction, and the speeds of absorption and desorption are in a trade-off relationship.

Therefore, since the reaction heat of the tertiary amine is smaller than that of the primary and secondary amines, the absorption rate is slow and the desorption (regeneration) rate is high. Deprived of heat, the desorption speed is not fast.

^{The solid carbon dioxide absorbent of the present invention has a porous structure having a specific surface area of 100 m 2} / g or more, which is composed of a secondary amine-containing organopolysiloxane having a three-dimensional structure itself without being encapsulated in a porous support. Therefore, the effective density of amine functional groups per unit weight is high, and a large amount of carbon dioxide can be absorbed. Furthermore, since it is composed of organopolysiloxane, it is highly hydrophobic, and it is not affected by the water content in the gas at most, and only the reaction of formula (d) that produces carbamate is dominant, and the reaction is because the functional group is a secondary amine. The heat is moderate and the absorption rate and desorption rate are well-balanced, enabling efficient separation and recovery of carbon dioxide.

As a result of diligent research on the balance between the adsorption rate and desorption rate of _{CO 2} and the energy saving required for desorption, the CO ₂ absorber of the present invention has reached a secondary amine-containing organopolysiloxane.

As a result of diligent studies, the present inventors have been able to absorb carbon dioxide in the air, at room temperature and under normal pressure, and desorb it under vacuum pressure to recover carbon dioxide. A low cost carbon dioxide absorber and recovery method can be provided. That is, the present invention constitutes the following items 1 to 13.

Item 1. A carbon dioxide absorbent that separates and recovers carbon dioxide and is characterized by being composed of a secondary amine-containing organopolysiloxane having a three-dimensional structure represented by the following general formula [I]. ..

[Chemical 4]
(SiO ₂ , SiO, 6CH ₂ ) _n (NH) _x (2CH ₂ ) _x-1 [I]
(In the formula, n = 10 or more, X = 1 to 10 integers.)

Item 2. Item 2. The carbon dioxide absorber according to Item 1, wherein the secondary amine-containing organopolysiloxane is composed of a secondary amine-containing organopolysiloxane having a three-dimensional structure represented by the following formula [II].

Item 3. Item 2. The carbon dioxide absorber according to Item 1, wherein the secondary amine-containing organopolysiloxane is composed of a secondary amine-containing organopolysiloxane having a three-dimensional structure represented by the following formula [III].

Item 4. Item 2. The carbon dioxide absorber according to any one of Items 1 to 3, wherein the secondary amine-containing organopolysiloxane having a three-dimensional structure does not invade or composite with the porous support.

Item 5. Item 2. The carbon dioxide absorber according to any one of Items 1 to 4, wherein the primary average particle size of the secondary amine-containing organopolysiloxane having a three-dimensional structure is 500 nm or less.

Item 6. Item 2. The carbon dioxide absorber according to any one of Items 1 to 5, wherein the specific surface area of the secondary amine-containing organopolysiloxane having a three-dimensional structure is 100 m ^{2 / g or more.}

Item 7. Item 2. The carbon dioxide absorber according to any one of Items 1 to 6, wherein the terminal hydroxyl group of the secondary amine-containing organopolysiloxane having a three-dimensional structure and aminosilane form a siloxane bond.

Item 8. Item 2. The carbon dioxide absorber according to any one of Items 1 to 6, wherein the terminal hydroxyl group of the secondary amine-containing organopolysiloxane having a three-dimensional structure and an alkoxysilane form a siloxane bond.

Item 9. The secondary amine-containing organopolysiloxane having the three-dimensional structure includes bis [3- (trimethoxysilyl) propyl] amine, bis [3- (trimethoxysilyl) propyl] ethylenediamine, and bis (3-triethoxysilylpropyl). Item 2. The carbon dioxide absorber according to any one of Items 1 to 6, wherein at least one is selected from the group of amine and bis [3- (triethoxysilyl) propyl] ethylenediamine and dehydrated and condensed. Manufacturing method.

Item 10. The aminosilane is 3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl)-. Item 7. The method for producing a carbon dioxide absorbent, which is one or more selected from the group of 3-aminopropylmethyldimethoxysilane and (3-trimethoxysilylpropyl) diethylenetriamine.

Item 11. The alkoxysilanes are methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, n-propyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and phenyl. Item 8. The method for producing a carbon dioxide absorbent according to Item 8, wherein the method for producing a carbon dioxide absorbent is one or more selected from triethoxysilane, diethoxydiphenylsilane, n-propyltriethoxysilane, hexyltriethoxysilane, and decyltriethoxysilane.

Item 12. A wall-flowing ceramic honeycomb and a carbon dioxide absorbent composed of a secondary amine-containing organopolysiloxane having the three-dimensional structure according to any one of Items 1 to 8 are provided, and the carbon dioxide absorbent is the wall-flowing ceramic honeycomb. A carbon dioxide separator that is carried in the wall vents of the honeycomb.

Item 13. Item 2. The carbon dioxide separation and recovery device according to Item 12, wherein carbon dioxide is adsorbed and separated under normal temperature and pressure, and carbon dioxide is supplied at room temperature at a vacuum pressure of −80 kPaG to −101 kPaG (gauge pressure). A carbon dioxide separation and recovery device including a carbon separator.

The carbon dioxide absorber of the present invention is more efficient and practical because it can increase the amount of carbon dioxide absorbed and can separate and recover a large amount of carbon dioxide with a short time decompression, and is suitable for carbon dioxide reuse. ing.

In addition, the carbon dioxide absorber of the present invention does not deteriorate the performance of absorption, desorption and reabsorption even when water vapor coexists, and does not require a dehumidification step. It is possible to reduce costs by using the system.

A conceptual diagram of a molecular structure in which a carbon dioxide absorbent material made of a secondary amine-containing organopolysiloxane having a three-dimensional structure has absorbed carbon dioxide. A carbon dioxide absorber in which the end of a secondary amine-containing organopolysiloxane having a three-dimensional structure is modified with N- (2-aminoethyl) -3-aminopropyltrimethoxysilane has a molecular structure in which carbon dioxide is absorbed. Conceptual diagram. FIG. 6 is a conceptual diagram of a molecular structure in which a carbon dioxide absorbent material in which the end of a secondary amine-containing organopolysiloxane having a three-dimensional structure is modified with n-propyltrimethoxysilane absorbs carbon dioxide. Wall circulation Concept of molecular structure in which the end of a secondary amine-containing organopolysiloxane having a three-dimensional structure is absorbed by carbon dioxide in a carbon dioxide separator modified with dimethyldiethoxysilane inside the porous wall of a ceramic honeycomb. figure. Conceptual diagram of carbon dioxide separation and recovery device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments.

The carbon dioxide absorber of the present invention is composed only of a secondary amine-containing organopolysiloxane having a three-dimensional structure without being supported on a porous support. The secondary amine-containing organopolysiloxane having the three-dimensional structure is represented by the following general formula [I]. In the following general formula [I], n = 10 or more, and X = 1 to 10.

[Chemical 7]
(SiO ₂ , SiO, 6CH ₂ ) _n (NH) _x (2CH ₂ ) _x-1 [I]

The n is more preferably an integer of 100 or more. Further, X is more preferably an integer of 1 to 3.

In the present invention, as a specific example of the secondary amine-containing organopolysiloxane having a three-dimensional structure, an amino represented by the following formula [II] having one secondary amine between two siloxane bonds. Examples include compounds. In the following formula [II], it is an integer of n = 10 or more.

Further, an amino compound represented by the following formula [III] having two secondary amines between two siloxane bonds can be mentioned. In the formula [III], it is an integer of n = 10 or more.

The carbon dioxide absorbent made of the secondary amine-containing organopolysiloxane having the three-dimensional structure of the present invention preferably has a primary average particle size of 500 nm or less, more preferably 200 nm or less.

The specific surface area of the carbon dioxide absorbent made of the secondary amine-containing organopolysiloxane having the three-dimensional structure of the present invention ^{is preferably 100 m 2} / g or more, and more preferably 180 m ² / g or more.

The secondary amine-containing organopolysiloxane having the three-dimensional structure of the present invention includes bis [3- (trimethoxysilyl) propyl] amine, bis [3- (trimethoxysilyl) propyl] ethylenediamine, and bis (3-triethoxysilyl) propyl. It can be produced by selecting at least one from the group of propyl) amine and bis [3- (triethoxysilyl) propyl] ethylenediamine as a raw material and dehydrating and condensing it.

The raw material is obtained by mixing with water to form a hydrated sol and dehydrating and condensing the hydrated sol by heating at 80 ° C. to 150 ° C. for 2 to 20 hours. More preferably, heating at 80 to 100 ° C. for 10 to 20 hours is preferable.

[Treatment of secondary amine-containing organopolysiloxane-terminated hydroxyl groups with a three-dimensional structure]
(Treatment with aminosilane coupling agent)
In the carbon dioxide absorber made of a secondary amine-containing organopolysiloxane having a three-dimensional structure of the present invention, a residue made of a hydroxyl group that cannot be dehydrated and condensed at the terminal may be treated by subjecting a siloxane bond with an aminosilane coupling agent. ..

(Type of aminosilane coupling agent)
The aminosilane coupling agent is 3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-amino). At least one may be selected from the group of (ethyl) -3-aminopropylmethyldimethoxysilane, (3-trimethoxysilylpropyl) diethylenetriamine.

(Processing method)
A secondary amine-containing organopolysiloxane having a three-dimensional structure is stirred and dispersed in water, an appropriate amount of the aminosilane coupling agent is added thereto, filtered, and heated and dried at 80 ° C to 130 ° C. A carbon dioxide absorber having a siloxane bond is obtained by dehydrating and condensing the hydroxide residue of the secondary amine-containing organopolysiloxane having a dimensional structure and the aminosilane coupling agent.

(Treatment with alkoxysilane coupling agent)
The aminosilane coupling agent is replaced with the alkoxysilane coupling agent, and in the same manner as described above, the carbon dioxide absorber made of the secondary amine-containing organopolysiloxane having the three-dimensional structure of the present invention has a hydroxyl group that cannot be dehydrated and condensed at the terminal. The residue consisting of the above may be treated by subjecting a siloxane bond with an alkoxysilane coupling agent.

(Type of alkoxysilane coupling agent)
The alkoxysilane coupling agent is methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, n-propyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, methyltriethoxysilane, dimethyldi. At least one may be selected from the group of ethoxysilane, phenyltriethoxysilane, diethoxydiphenylsilane, n-propyltriethoxysilane, hexyltriethoxysilane and decyltriethoxysilane.

(Processing method)
A secondary amine-containing organopolysiloxane having a three-dimensional structure is stirred and dispersed in water, an appropriate amount of the alkoxysilane coupling agent is added thereto, filtered, and heated and dried at 80 ° C to 130 ° C. A carbon dioxide absorber having a siloxane bond is obtained by dehydrating and condensing the hydroxide residue of the secondary amine-containing organopolysiloxane having a three-dimensional structure and the aminosilane coupling agent.

(Carbon dioxide separator)
The sol of the present invention may be molded into a separation membrane and a separator made of a secondary amine-containing organopolysiloxane having a three-dimensional structure.

(Manufacturing method of carbon dioxide separator)
For example, as an example of the separator, a diesel particulate filter (hereinafter referred to as DPF) that collects soot and burns and purifies it, which is used for aftertreatment of diesel exhaust gas in automobiles, may be used. The DPF is generally a wall-circulating ceramic honeycomb structure, and the porosity of the wall is preferably 50 to 65%, more preferably 60 to 65%, from the viewpoint of increasing the effective volume of the carbon dioxide absorbent. The average hole diameter of the wall is preferably 7 to 20 μm, preferably 13 to 20 μm. The number of honeycomb cells is preferably 200 to 400, more preferably 300 to 400. As the number of cells increases, the wall thickness is preferably 0.3 to 0.46 mm, more preferably 0.3 to 0.4 mm. The hydrated sol of the present invention is impregnated in the wall of the DPF to form a secondary amine-containing organopolysiloxane having a three-dimensional structure, and a isolate can be obtained. A conceptual diagram of the separated body is shown in FIG.

(Absorber)
Further, the hydrated sol of the present invention may be molded into the shape of sleeves, pellets and beads by a known method such as a pelletizer, heat-dehydrated and condensed, and filled in the absorption ridge for use. Since the shape can be processed without using a binder during the molding process, there is an advantage that the carbon dioxide absorption performance can be maintained.

(Carbon dioxide separation and recovery device)
In the carbon dioxide separation and recovery apparatus of the present invention, a secondary amine-containing organopolysiloxane having a porous three-dimensional structure without using a support is supported on a sleeve, an absorber formed into pellets, a DPF, or the like. A plate-shaped or sleeve-shaped work piece in which a film is formed on an aggregate having a separate body or a mesh or a mesh is filled in the adsorption column shown in FIG. Absorb (for example, 5 minutes). Table 1 shows the names of the symbols appearing in FIG.

On the other hand, carbon dioxide can be desorbed (separated) using a vacuum pump at reduced pressure of -80 to -101 kPaG (gauge pressure) and normal temperature (for example, 5 minutes). Carbon dioxide is absorbed and desorbed alternately in a cycle, and if necessary for carbon dioxide recycling, it is held in a buffer tank and / or collected and stored in a compression cylinder with a pressure pump.

Table 2 shows an example of the operation method of the carbon dioxide separation and recovery device of the present invention. The cleaning steps shown in Table 2 may be performed according to the recycling application in which it is necessary to increase the purity of carbon dioxide. For example, in the case of growing a plant that uses carbon dioxide on the spot, a washing step is not required.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
Example 1 comprises a secondary amine-containing organopolysiloxane having a three-dimensional network structure by dehydrating and condensing hydrolyzed silanol using bis [3- (trimethoxysilyl) propyl] amine as a raw material. A carbon dioxide absorber was obtained.

First, while stirring 30 g of ion-exchanged water, bis [3- (trimethoxysilyl) propyl] amine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to obtain a sol. Then, after washing with filtered water, it was dried at 80 ° C. for 16 hours, and the powder of the secondary amine-containing organopolysiloxane having a three-dimensional structure was pulverized in a mortar to obtain a carbon dioxide absorbent. The obtained carbon dioxide absorbent had an average particle size of 213 nm and a specific surface area of 186 m ² / g. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Example 2)
Example 2 is the same as in Example 1 except that bis [3- (trimethoxysilyl) propyl] amine is replaced with bis [3- (trimethoxysilyl) propyl] ethylenediamine. A carbon absorber was obtained.

While stirring 30 g of ion-exchanged water, bis [3- (trimethoxysilyl) propyl] ethylenediamine (manufactured by Merck KGaA) was added to obtain a sol. Then, after washing with filtered water, it was dried at 80 ° C. for 16 hours, and the powder of the secondary amine-containing organopolysiloxane having a three-dimensional structure was pulverized in a mortar to obtain a carbon dioxide absorbent. The obtained carbon dioxide absorbent had an average particle size of 385 nm and a specific surface area of 233 m ² / g. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Example 3)
In Example 3, the terminal hydroxyl group of the secondary amine-containing organopolysiloxane powder having the three-dimensional structure obtained in Example 1 was used as N- (2-aminoethyl) -3-aminopropyltrimethoxysilane. It was dehydrated and condensed and treated. First, while stirring 30 g of ion-exchanged water, 1 g of the secondary amine-containing organopolysiloxane powder having the three-dimensional structure obtained in Example 1 was dispersed therein, and N- (2-aminoethyl) -3-amino was dispersed therein. 0.1 g of propyltrimethoxysilane was added, and stirring was continued for 30 minutes. Then, after washing with filtered water, it was dried at 80 ° C. for 16 hours, and the treated powder was pulverized in a mortar to obtain a carbon dioxide absorbent. The obtained carbon dioxide absorbent had an average particle size of 274 nm and a specific surface area of 174 m ² / g. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Example 4)
In Example 4, the terminal hydroxyl group of the secondary amine-containing organopolysiloxane powder having the three-dimensional structure obtained in Example 1 was dehydrated and condensed with n-propyltriethoxysilane. First, while stirring 30 g of ion-exchanged water, 1 g of the secondary amine-containing organopolysiloxane powder having the three-dimensional structure obtained in Example 1 was dispersed, and 0.1 g of n-propyltriethoxysilane was added thereto to 30. Stirring for minutes was continued. Then, after washing with filtered water, it was dried at 80 ° C. for 16 hours, and the treated powder was pulverized in a mortar to obtain a carbon dioxide absorbent. The obtained carbon dioxide absorbent had an average particle size of 258 nm and a specific surface area of 176 m ² / g. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Comparative Example 1)
In Comparative Example 1, a powder of a carbon dioxide solid absorbent treated with (3-trimethoxysilylpropyl) diethylenetriamine using mesoporous silica SBA-15 as a support was used.

(Adjustment method of mesoporous silica SBA-15)
First, tetraethoxysilane (abbreviation: TEOS, Kishida) was dissolved in a solution prepared by dissolving 50 g of a triblock copolymer (abbreviation: EO20PO70EO20,) having a polyethylene oxide chain-polypropylene oxide chain-polyethylene oxide chain in ^{1.3 dm 3} of distilled water. 110 g (manufactured by Chemical Co., Ltd.) was added, and the mixture was stirred for 5 minutes. This solution in 36 volume percent hydrochloric acid (manufactured by Wako Pure Chemical Industries, Ltd.) 175cm ³ was added over 30 min, 35 ° C., and stirred under heating for 20 hours, further 95 ° C., the mixture was heated and stirred 24 hours. The produced solid was collected by suction filtration ^{, washed with distilled water 4 dm 3} , and then dried overnight in a constant temperature bath kept at 70 ° C. to obtain a powder of mesoporous silica SBA-15. ..

Treatment with (3-Trimethoxysilylpropyl) Diethylenetriamine Next, 5.0 g of the support SBA-15 dried for 6 hours in a constant temperature bath kept at 125 ° C. ^{was added to 250 cm 3} of dehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd.). After stirring for 5 minutes, (3-trimethoxysilylpropyl) diethylenetriamine (manufactured by Aldrich), 50 cm ³ was added thereto. The mixture was refluxed and stirred at 110 ° C. for 24 hours in an argon gas stream and then cooled to room temperature. The solid matter recovered by suction filtration of the cooled mixture was washed with dehydrated toluene 200 cm ³ (manufactured by Wako Pure Chemical Industries, Ltd.) and then dried overnight in a constant temperature bath maintained at 60 ° C. (3-trimethoxy). A support powder treated with silylpropyl) diethylenetriamine was obtained. This powder had an average particle size of 10 μm and a specific surface area of 355 m ² / g. The obtained powder was used as a carbon dioxide solid absorber in the carbon dioxide separation / recovery performance evaluation test described later. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Comparative Example 2)
Comparative Example 2 is a gel obtained by dehydration condensation of 3-aminopropyltriethoxysilane without using a support. First, 3-aminopropyltriethoxysilane (manufactured by Aldrich, USA) was collected in a petri dish manufactured by Teflon (registered trademark), left in a desiccator at 25 ° C. saturated with water vapor for 24 hours, and further. It was left in a desiccator at about 60 ° C. saturated with water vapor for 24 hours, and then dried overnight in a constant temperature bath at 60 ° C. to hydrolyze and condense the silane coupling agent to obtain a powder. This powder had an average particle size of 3 μm and a specific surface area of 0.1 m ² / g. The obtained powder was used as a carbon dioxide solid absorber in the carbon dioxide separation / recovery performance evaluation test described later. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Comparative Example 3)
Comparative Example 3 is a carbon dioxide absorbent obtained by treating beads of polymethylmethacrylate PMMA with 2-isopropylaminoethanol (IPAE). First, 2-isopropylaminoethanol (IPAE) was weighed in a predetermined amount (6.67 g in total) so as to be 40% by weight of the solid absorbent, and methanol was measured in a flask having a capacity of 300 cc (Wako Pure Chemical Industries, Ltd. special grade). After being dissolved in 20 g, polymethylmethacrylate PMMA beads (Diaion HP2MG manufactured by Mitsubishi Chemical Corporation; effective diameter 0.3 mm or more; specific surface area 570 m ² / g; pores; A volume of 1.3 mL / g) was added, and the mixture was stirred at room temperature for 2 hours, and then heated to 50 ° C. with a rotary evaporator (N-1000 manufactured by EYELA), and the pressure in the system became 0.03 MPa. The methanol solvent was removed by reducing the pressure to the maximum, and a solid absorbent material in which the amine was uniformly supported on the support was prepared. For the removal of the methanol solvent, the total weight of the flask and the reagents was weighed in advance, and the preparation was completed when a weight loss of 20 g corresponding to the methanol solvent was confirmed. The PMMA beads had a specific surface area of 173 m ² / g. The obtained beads were used as a carbon dioxide absorbent in the carbon dioxide absorption performance evaluation test described later.

(Comparative Example 4)
Comparative Example 4 is a carbon dioxide absorbent obtained by treating mesoporous silica MSU-F with diisopropylated tetraethylenepentamine.

(Synthesis of diisopropylated tetraethylenepentamine (hereinafter, "IP-TEPA"))
First, 1 mol of tetraethylenepentamine (TEPA) and a stir bar were placed in a 2 L flask equipped with a reflux tube, and 2.0 mol of potassium carbonate dissolved in a very small amount of water was added to the flask. While stirring the mixture while cooling the flask with ice, 400 mL of ethanol in which 2.0 mol of 2-bromopropane was dissolved was slowly added dropwise thereto. After the addition of the ethanol solution was completed, the flask was returned to room temperature and the reaction solution was stirred at room temperature for 36 hours. After confirming the completion of the reaction with a liquid chromatograph mass spectrometer (LC-MS), water and ethanol were removed under reduced pressure at 40 ° C. to obtain a residue. Methanol was added to the obtained residue, and the insoluble material was filtered. Methanol was removed under reduced pressure to obtain 259.79 g (yield 95%) of IP-TEPA, which is a pale yellow transparent liquid.

Preparation of (IP-TEPA (40) / MeOH-F) Next, the obtained IP-TEPA was quantitatively weighed so as to be 40% by weight of the carbon dioxide separating material, and this was weighed in an eggplant flask having a capacity of 300 cc. It was dissolved in 20 g of the obtained methanol (manufactured by Wako Pure Chemical Industries, Ltd .; special grade). Then, this was added to 10 g of a separately weighed support MeOH-F (manufactured by Aldrich; mesoporous silica; specific surface area 550 m ² / g, pore diameter 20 nm, pore volume 2.0 mL / g), and stirred at room temperature for 2 hours. After that, while heating this to 60 ° C. with a rotary evaporator (manufactured by EYELA; N-1000), the pressure in the system is reduced to 0.03 MPa to remove the methanol solvent and use amine as a support. A uniformly supported carbon dioxide solid absorber was prepared. For the removal of the methanol solvent, the total weight of the flask and the reagents was weighed in advance, and the preparation was completed when a weight loss of 20 g corresponding to the methanol solvent was confirmed. The average particle size of this carbon dioxide solid absorbent material was 13 μm, and the specific surface area was 84 m ² / g. The obtained carbon dioxide solid absorbent powder was used in the carbon dioxide absorption performance evaluation test described later. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Comparative Example 5)
In Comparative Example 5, beads of a carbon dioxide solid absorbent were obtained in the same manner as in Comparative Example 4, except that the support MSU-F was replaced with beads of polymethylmethacrylate PMMA (HP2MG).

Preparation of (IP-TEPA (40) / PPMA) In the same manner as in Comparative Example 4, the obtained IP-TEPA was quantitatively weighed so as to be 40% by weight of the carbon dioxide separator, and polymethylmethacrylate PMMA was used as a support. (Made by Mitsubishi Chemical Corporation; Diaion (registered trademark) HP2MG; effective diameter 0.3 mm or more, specific surface area 570 m ² / g, pore diameter 19 nm, pore volume 1.3 mL / g) 10 g was used.

The PMMA beads containing IP-TEPA (40) had an average particle size of 0.34 mm and a specific surface area of 99 m ² / g. The beads of the obtained carbon dioxide solid absorbent material were used in the carbon dioxide absorption performance evaluation test described later. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Comparative Example 6)
In Comparative Example 6, beads of polymethylmethacrylate PPMA (HP2MG) were treated in the same manner as in Comparative Example 5 except that IP-TEPA was synthesized in place of IP-Spermine to obtain beads of a solid carbon dioxide absorber. Obtained.

Synthetic spermine diisopropylated (hereinafter referred to as "IP-Spermine") 25 g (0.12 mol) of spermine and a stir bar were placed in a 500 mL flask equipped with a reflux tube, and 0.49 mol of potassium carbonate dissolved in a very small amount of water. Was added to the flask. While stirring the mixture while cooling the flask with ice, 150 mL of ethanol in which 60.78 g (0.49 mol) of 2-bromopropane was dissolved was slowly added dropwise. After the addition of the ethanol solution was completed, the flask was returned to room temperature and the reaction solution was stirred at room temperature for 36 hours. After completion of the reaction, water and ethanol were removed under reduced pressure at 40 ° C. to obtain a residue. Methanol was added to the obtained residue, and the insoluble material was filtered. Methanol was removed under reduced pressure to obtain 29.42 g (yield 83%) of IP-Spermine, which is a colorless liquid.

Preparation of (IP-Spermine (40) / PPMA) Next, the obtained IP-Spermine was quantitatively weighed so as to be 40% by weight of the carbon dioxide separator, and polymethylmethacrylate beads (Mitsubishi Chemical Corporation) as a support. Manufactured by: Diaion (registered trademark) HP2MG; effective diameter 0.3 mm or more, specific surface area 570 m ² / g, pore diameter 19 nm, pore volume 1.3 mL / g) 10 g was used. The obtained carbon dioxide solid absorbent beads had an average particle size of 0.33 mm and a specific surface area of 97 m ² / g, and were used in the carbon dioxide absorption performance evaluation test described later. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Comparative Example 7)
In Comparative Example 7, polymethylmethacrylate PMM beads were treated with N, N, N', N'-tetramethyl-1,6-diaminohexane and [2- (2-benzoxazolyl) phenolate] zinc. , Carbon dioxide solid absorber beads.

N, N, N', N'-tetramethyl-1,6-diaminohexane (TMDAH), which is a tertiary alkylamine, was added to water and mixed to make TMDAH: 30% by weight and water: 70% by weight. The amount of [2- (2-benzoxazolyl) phenolate] zinc (BOPZ) added as a catalyst was 1.0% by weight of the amine compound TMDAH. Since the BOPZ has no solubility in the absorbent TMDAH, it was suspended non-uniformly in the absorbent.

Next, a predetermined amount (6.67 g in total) of the absorbent TMDAH containing the BOPZ was weighed so as to be 40% by weight of the solid absorbent, and methanol was measured in a flask having a capacity of 300 cc (Wako Pure Chemical Industries, Ltd. special grade). After dissolving in 20 g, as a support to be supported, 10 g of polymethylmethacrylate methanol beads (HP2MG) was added in the same manner as in Comparative Example 3, and after stirring at room temperature for 2 hours, this was used as a rotary evaporator (manufactured by EYELA). While heating to 50 ° C. with N-1000), the pressure in the system was reduced to 0.03 MPa to remove the methanol solvent, and the amine was uniformly treated on the support beads to absorb the carbon dioxide solid. Wood beads were prepared. The treated beads had an average particle size of 0.35 mm and a specific surface area of 168 m ² / g. The beads of the obtained carbon dioxide solid absorbent material were used in the carbon dioxide absorption performance evaluation test described later. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Comparative Example 8)
Comparative Example 7 absorbs solid carbon dioxide in the same manner as in Comparative Example 7 except that [2- (2-benzoxazolyl) phenolate] zinc was replaced with bis (2,4-pentanionate) magnesium. The material was prepared. TMDAH, which is a tertiary alkylamine, was added to water and mixed to make TMDAH: 30% by weight and water: 70% by weight. The amount of bis (2,4-pentanionate) magnesium (PDM) added as a catalyst was 2.5% by weight of the amine compound TMDAH. Since the PDM has no solubility in the absorbent TMDAH, it was suspended non-uniformly in the absorbent.

Next, a predetermined amount (6.67 g in total) of the absorbent TMDAH containing the PDM was weighed so as to be 40% by weight of the solid absorbent, and methanol was measured in a flask having a capacity of 300 cc (Wako Pure Chemical Industries, Ltd. special grade). After dissolving in 20 g, as a support to be supported, 10 g of polymethylmethacrylate PMMA beads (HP2MG) was added in the same manner as in Comparative Example 3, and after stirring at room temperature for 2 hours, this was used as a rotary evaporator (manufactured by EYELA). While heating to 50 ° C. with N-1000), the pressure in the system was reduced to 0.03 MPa to remove the methanol solvent, and the amine was uniformly treated on the support beads to absorb the carbon dioxide solid. The material was prepared. The treated beads had an average particle size of 0.34 mm and a specific surface area of 155 m ² / g. The beads of the obtained carbon dioxide solid absorbent material were used in the carbon dioxide absorption performance evaluation test described later. The average particle size was determined by measuring n = 100 particles from an electron microscope image and arithmetically averaging the measured values.

(Carbon dioxide separation / recovery performance evaluation test)
1.0 g of the carbon dioxide absorbers of Examples 1 to 3 and Comparative Examples 1 to 8 thus obtained were filled in a glass U-shaped tube (inner diameter 10 mm, height 150 mm), and both ends were made of glass. Fixed with wool. A glass U-shaped tube filled with the solid absorbent was immersed in a constant temperature water tank, and the temperature was set to 25 ° C. to prepare a reaction tube. A mixed gas of 20% by volume of carbon dioxide and 80% by volume of nitrogen gas was circulated at 0.5 L / min at atmospheric pressure from one side of the reaction tube filled with the solid absorbent.

The carbon dioxide concentration in the gas at the inlet and outlet of the reaction tube is continuously measured with a carbon dioxide meter (Gas analyzer VA-3001 manufactured by Horiba Seisakusho), and the difference in carbon dioxide flow rate between the inlet and outlet of the reaction tube is used. The amount of carbon dioxide absorbed (A) for 5 minutes was measured. Next, the inlet of the reaction tube was closed with a valve, and the outlet side was depressurized and exhausted by a vacuum pump, and the carbon dioxide flow rate was continuously measured to measure the amount of carbon dioxide desorption (recovery) (B) for 5 minutes. The vacuum pressure reached -100 kPaG 1 minute after the start of depressurization and was retained thereafter. The obtained results are shown in Table 3 as the amount of carbon dioxide (g) per 1 kg of carbon dioxide absorbent.

Next, the carbon dioxide absorption amount (A) for 5 minutes at 25 ° C. and 5 at a reduced pressure of -100 kPaG were obtained in the same manner as above, except that water vapor was added to the mixed gas using a humidifier to obtain a relative humidity of 80% RH. The amount of carbon dioxide desorbed (recovered) per minute (B) was measured. The obtained results are shown in Table 4 as the amount of carbon dioxide (g) per 1 kg of carbon dioxide absorbent.

As shown in Tables 3 and 4 above, Examples 1 to 4 absorb a large amount of carbon dioxide in a short time of 5 minutes at normal temperature and pressure as compared with Comparative Examples 1 to 8, and similarly reduce the pressure for 5 minutes. Desorption (separation) was 90% or more, demonstrating that it can be recovered efficiently.

1 Secondary amine-containing organopolysiloxane having a three-dimensional structure 10 Absorption by carbamate of carbon dioxide 11 Modification with N- (2-aminoethyl) -3-aminopropyltrimethoxysilane 12 Modification with n-propyltrimethoxysilane 13 Modification with dimethyldiethoxysilane 14 Wall-flowing ceramic honeycomb 15 Inside wall-flowing

Claims

A carbon dioxide absorbent that separates and recovers carbon dioxide.
A carbon dioxide absorbent comprising a secondary amine-containing organopolysiloxane having a three-dimensional structure represented by the following general formula [I].
[Chemical 1]
(SiO 2 , SiO, 6CH 2 ) n (NH) x (2CH 2 ) x-1 [I]
(In the formula, n = 10 or more, X = 1 to 10 integers.)
The carbon dioxide absorption according to claim 1, wherein the secondary amine-containing organopolysiloxane comprises a secondary amine-containing organopolysiloxane having a three-dimensional structure represented by the following formula [II]. Material.
The carbon dioxide absorption according to claim 1, wherein the secondary amine-containing organopolysiloxane comprises a secondary amine-containing organopolysiloxane having a three-dimensional structure represented by the following formula [III]. Material.
The carbon dioxide absorber according to any one of claims 1 to 3, wherein the secondary amine-containing organopolysiloxane having the three-dimensional structure is not impregnated or composited with the porous support.
The carbon dioxide absorber according to any one of claims 1 to 4, wherein the primary average particle size of the secondary amine-containing organopolysiloxane having the three-dimensional structure is 500 nm or less.
The carbon dioxide absorber according to any one of claims 1 to 5, wherein the specific surface area of the secondary amine-containing organopolysiloxane having a three-dimensional structure is 100 m 2 / g or more.
The carbon dioxide absorber according to any one of claims 1 to 6, wherein the terminal hydroxyl group of the secondary amine-containing organopolysiloxane having the three-dimensional structure and aminosilane form a siloxane bond.
The carbon dioxide absorber according to any one of claims 1 to 6, wherein the terminal hydroxyl group of the secondary amine-containing organopolysiloxane having a three-dimensional structure and an alkoxysilane form a siloxane bond. ..
From bis [3- (trimethoxysilyl) propyl] amine, bis [3- (trimethoxysilyl) propyl] ethylenediamine, bis (3-triethoxysilylpropyl) amine, bis [3- (triethoxysilyl) propyl] ethylenediamine The method for producing a carbon dioxide absorbent according to any one of claims 1 to 6, wherein at least one is selected and dehydrated and condensed.
The aminosilane is 3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl)-. The method for producing a carbon dioxide absorbent according to claim 7, wherein the carbon dioxide absorber is one or more selected from the group of 3-aminopropylmethyldimethoxysilane and (3-trimethoxysilylpropyl) diethylenetriamine.
The alkoxysilanes are methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, n-propyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and phenyl. The method for producing a carbon dioxide absorbent according to claim 8, wherein the method for producing a carbon dioxide absorbent is one or more selected from triethoxysilane, diethoxydiphenylsilane, n-propyltriethoxysilane, hexyltriethoxysilane, and decyltriethoxysilane.
Wall distribution ceramic honeycomb and
A carbon dioxide absorbent made of a secondary amine-containing organopolysiloxane having the three-dimensional structure according to any one of claims 1 to 8 is provided.
The carbon dioxide absorbent is a carbon dioxide separator supported on the wall vents of the wall-flowing ceramic honeycomb.
A carbon dioxide separation and recovery device that adsorbs and separates carbon dioxide under normal temperature and pressure, and supplies carbon dioxide at room temperature at a vacuum pressure of -80 kPaG to -101 kPaG (gauge pressure).
A carbon dioxide separation and recovery device comprising the carbon dioxide separator according to claim 12.