Structure and carbon dioxide recovery device equipped with the structure

Abstract

To provide a structure that is able to efficiently adsorb and absorb carbon dioxide and able to make the cost of desorbing / releasing carbon dioxide low.SOLUTION: A structure for carbon dioxide recovery, in which a reaction layer comprising a substrate, a carrier, and an adsorbent that adsorbs and desorbs carbon dioxide carried on the carrier and a heating layer for heating the reaction layer are alternately layered is characterized in that a width of the reaction layer between the two heating layers is 20 to 100 cm, and a volume ratio of the reaction layer (a volume of the reaction layer / (the volume of the reaction layer + a volume of the heating layer) is 0.6 to 0.9.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a structure and a carbon dioxide recovery device equipped with the structure. [Background technology]

[0002] It is widely known that carbon dioxide (CO2) concentrations show a strong correlation with global warming, which includes rising atmospheric temperatures and an increased likelihood of natural disasters such as typhoons and floods. Industries such as power plants, oil refineries, cement plants, and steel production processes release large amounts of CO2 from their plants, and reducing these CO2 emissions is a major concern.

[0003] To address the above problems, capturing and storing released CO2 has been studied and considered for some time. This method is excellent because it can substantially reduce CO2 emissions, and various methods that do not require major changes to the basic process are being investigated.

[0004] One method used to capture CO2 involves supporting amines as absorbents on pellets, but it is difficult to achieve a large contact area with the CO2. Therefore, attempts are being made to increase the contact area in order to increase the amount of CO2 absorbed by the absorbent. In addition, in order to release the CO2 absorbed by the amine, it is necessary to heat it to about 120°C, and this is generally done using inexpensive steam discharged from power plants. However, when steam is used, moisture adheres to the absorbent, so the absorbent containing moisture needs to be dried, requiring drying equipment and increasing costs. To solve these problems, the following devices and methods have been proposed.

[0005] Specifically, Patent Document 1 discloses an apparatus for recovering carbon dioxide by immersing a honeycomb-shaped substrate (honeycomb structure) in a slurry containing a carrier, thereby coating the substrate with a carrier, and further coating the carrier with an adsorbent using a slurry containing an adsorbent such as an amine.

[0006] Patent Document 2 discloses a carbon dioxide recovery and release device that has an adsorption section in which multiple adsorption units are stacked, each unit comprising a permeable container containing pelletized zeolite and a heater installed around the permeable container.

[0007] Patent Document 3 discloses a method using a honeycomb structure as a substrate, in which an adsorbent is formed on the surface of the partition walls and thermally conductive filaments are provided inside the partition walls.

[0008] Patent Document 4 discloses a honeycomb structure in which the substrate is made of activated carbon and an adsorbent is formed on the surface, and a conductive dopant material is included in the porous cell walls constituting the honeycomb structure, thereby making the honeycomb structure electrically conductive and capable of generating heat. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Special Publication No. 2014-533195 [Patent Document 2] Japanese Patent Publication No. 2019-98220 [Patent Document 3] Special Publication No. 2013-540573 [Patent Document 4] Japanese Patent Publication No. 2015-128771 [Overview of the project] [Problems that the invention aims to solve]

[0010] In the CO2 recovery apparatus described in Patent Document 1, nitrogen gas or steam is used as a means of heating the honeycomb structure. However, when nitrogen gas is used, it is necessary to heat the nitrogen gas, which requires the installation of nitrogen gas heating equipment, thus increasing the recovery cost. When steam is used, as mentioned above, the adsorbent containing moisture must be dried.

[0011] Furthermore, in the apparatus described in Patent Document 2, since the adsorbent is pellets, there is a problem in that when the gas containing CO2 passes through the layer containing the pellets, there is a large pressure loss, requiring a large pressure to be applied to the adsorption part, and the heat transfer efficiency from the heater is low, resulting in high costs for CO2 desorption and release. Furthermore, the methods described in Patent Documents 3 and 4 involve heating by electric current, which is not a cheaper heating method compared to steam, and still suffers from the problem of high costs associated with CO2 desorption and release.

[0012] The present invention was made to solve the above problems and aims to provide a structure that can efficiently adsorb and absorb carbon dioxide and keep the cost of desorption and release of carbon dioxide low, as well as a carbon dioxide recovery device equipped with the above structure. [Means for solving the problem]

[0013] The present invention provides a structure for carbon dioxide recovery in which a reaction layer comprising a substrate, a support, and an adsorbent for adsorbing and desorbing carbon dioxide supported on the support, and a heating layer for heating the reaction layer are alternately stacked, The width of the reaction layer located between the two heating layers is 20 to 100 cm, and the volume ratio of the reaction layer (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) is 0.6 to 0.9.

[0014] According to the structure of the present invention, a reaction layer that performs carbon dioxide adsorption and desorption and a heating layer for heating the reaction layer are alternately stacked, and since the heating layer is provided separately from the reaction layer that performs carbon dioxide deadsorption, the heat source and the adsorbent of the reaction layer do not come into direct contact, inexpensive steam or the like can be used as the heat source for the heating layer, and furthermore, there is no need to evaporate the water adsorbed on the adsorbent of the reaction layer, so that heating costs can be reduced. Furthermore, the width of the reaction layer between the two heating layers is set to 20-100 cm, and the volume ratio of the reaction layer (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) is set to 0.6-0.9. This allows for sufficient volume in the reaction layer and reduces the number of layers, resulting in excellent cost performance and efficient heating of the reaction layer by the heating layer. In this specification, adsorption and desorption are used to include not only adsorption and desorption, but also absorption and release. Furthermore, an adsorbent refers to a substance that adsorbs and absorbs carbon dioxide and desorbs and releases it at a predetermined temperature.

[0015] In the structure of the present invention, if the width of the reaction layer is less than 20 cm, it becomes necessary to manufacture and assemble a large number of reaction layers and heating layers, which increases the manufacturing cost of the structure. Furthermore, the adhesive layer between the reaction layer and the heating layer increases, making it difficult to efficiently and inexpensively adsorb and desorb carbon dioxide. On the other hand, if the total number of reaction layers exceeds 100 cm, the time required to transfer heat from the heating layer becomes too long, making it difficult to efficiently and inexpensively adsorb and desorb carbon dioxide.

[0016] In the structure of the present invention, if the volume ratio of the reaction layer (volume of the reaction layer / volume of the reaction layer and other parts + volume of the heating layer) exceeds 0.9, the heat supply from the heating layer is insufficient, making it difficult to raise the temperature of the reaction layer and thus difficult to efficiently and inexpensively adsorb and desorb carbon dioxide. On the other hand, if the volume ratio of the reaction layer to the heating layer (volume of the reaction layer / volume of the heating layer) is less than 0.6, the volume of the reaction layer decreases, resulting in a smaller amount of carbon dioxide adsorbed and desorbed per unit volume, which also makes it difficult to efficiently and inexpensively adsorb and desorb carbon dioxide.

[0017] In the structure of the present invention, it is desirable that the substrate constituting the reaction layer is a honeycomb structure in which a plurality of through-holes serving as flow passages for a gas containing carbon dioxide are arranged side by side in the extending direction of the through-holes with a partition wall therebetween.

[0018] In the structure of the present invention, when the substrate constituting the reaction layer is a honeycomb structure in which a plurality of through-holes serving as flow passages for a gas containing carbon dioxide are arranged side by side in the extending direction of the through-holes with a partition wall therebetween, since the pressure loss in the flow passage is low, it is not necessary to apply a large pressure to the reaction layer. Further, as compared with the case where pellets or the like are used as the adsorbent, the surface area of the layer containing the adsorbent on which the adsorbent is supported can be increased, and heat transfer is also good, so that a large amount of carbon dioxide can be efficiently adsorbed and desorbed.

[0019] In the structure of the present invention, it is desirable that the honeycomb structure is the substrate and the carrier. In the structure of the present invention, when the honeycomb structure is the substrate and the carrier, the adsorbent can be directly supported on the through-holes of the honeycomb structure, heat transfer to the adsorbent is also good, and the adsorbent can efficiently adsorb and desorb carbon dioxide.

[0020] In the structure of the present invention, it is desirable that the heat conductivity of the honeycomb structure is 15 to 300 W / m·K. In the structure of the present invention, when the heat conductivity of the honeycomb structure is 15 to 300 W / m·K, heat from the heating layer is efficiently transferred to the reaction layer, and in the reaction layer, carbon dioxide can be efficiently adsorbed and desorbed.

[0021] When the heat conductivity of the honeycomb structure is less than 15 W / m·K, it becomes difficult to transfer heat in the reaction layer, and the amount of carbon dioxide adsorbed and desorbed decreases. On the other hand, when the heat conductivity of the honeycomb structure exceeds 300 W / m·K, the manufacturing cost of the honeycomb structure increases, or it becomes difficult to obtain such a material, and the manufacturing of the honeycomb structure becomes difficult.

[0022] In the structure of the present invention, it is preferable that the substrate consists of at least one selected from the group consisting of carbon, metal, and high thermal conductivity ceramic.

[0023] In the structure of the present invention, if the substrate is made of at least one selected from the group consisting of carbon, metal, and highly thermally conductive ceramic, the support has high thermal conductivity and can efficiently receive heat from the heating layer, thereby efficiently and quickly desorbing the carbon dioxide adsorbed and absorbed by the adsorbent.

[0024] In the structure of the present invention, it is preferable that the heating layer consists of a plate-shaped heat transfer element or a heat transfer element having one or more through holes that serve as flow passages for a heating fluid, and is bonded to the reaction layer.

[0025] In the structure of the present invention, if the heating layer is made of a plate-shaped heat transfer material or a heat transfer material having one or more through holes that serve as flow passages for a heating fluid, and is bonded to the reaction layer, then heat from the heating layer can be efficiently transferred to the reaction layer via the bonding layer. Furthermore, in the case of a heat transfer element with through holes, heat from a heat source such as steam is transferred to the heating layer through the through holes, which have a large surface area, allowing the reaction layer to be heated efficiently.

[0026] In the structure of the present invention, it is desirable that the honeycomb structure and the heat transfer element are stacked such that the flow passages of the honeycomb structure constituting the reaction layer and the flow passages of the heat transfer element constituting the heating layer intersect.

[0027] In the structure of the present invention, if the honeycomb structure constituting the reaction layer and the heat transfer element constituting the heating layer are stacked so that their flow passages intersect, the fluids flowing to the reaction layer and the heating layer can be allowed to flow in and out without mixing. Therefore, carbon dioxide can be adsorbed and desorbed efficiently and at low cost.

[0028] The carbon dioxide recovery device of the present invention is characterized by comprising the above-described structure.

[0029] Since the carbon dioxide recovery device of the present invention is equipped with the above-described structure, it is possible to provide a carbon dioxide recovery device that can efficiently and inexpensively adsorb and desorb carbon dioxide. [Brief explanation of the drawing]

[0030] [Figure 1] Figure 1 is a schematic perspective view showing an example of the structure of the present invention. [Figure 2A] Figure 2A is a schematic cross-sectional view showing a honeycomb molded body produced by the manufacturing method of the structure of the present invention. [Figure 2B] Figure 2B is a cross-sectional view of the honeycomb molded body shown in Figure 2A, along line AA. [Figure 3A] Figure 3A is a schematic cross-sectional view showing one step in the manufacturing method of the heat transfer element according to the present invention. [Figure 3B] Figure 3B is a schematic cross-sectional view showing a heat transfer body obtained by the heat transfer body manufacturing method of the present invention. [Figure 4] Figure 4 is a schematic diagram illustrating a carbon dioxide capture device equipped with the structure of the present invention.

[0031] (Detailed description of the invention) The structure of the present invention will be described below. The present invention provides a carbon dioxide recovery structure comprising a reaction layer consisting of a substrate, a support, and an adsorbent for adsorbing and desorbing carbon dioxide supported on the support, and a heating layer for heating the reaction layer, which are alternately stacked. The width of the reaction layer located between the two heating layers is 20 to 100 cm, and the volume ratio of the reaction layer (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) is 0.6 to 0.9.

[0032] According to the structure of the present invention, a reaction layer for adsorption and desorption of carbon dioxide and a heating layer for heating the reaction layer are alternately stacked. Since the heating layer is provided separately from the reaction layer for deadsorption of carbon dioxide, the heat source and the adsorbent of the reaction layer do not come into direct contact. Inexpensive steam or the like can be used as the heat source for the heating layer. Furthermore, there is no need to evaporate the water adsorbed on the adsorbent of the reaction layer, which reduces the cost of heating. Furthermore, the width of the reaction layer between the two heating layers is set to 20-100 cm, and the volume ratio of the reaction layer (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) is set to 0.6-0.9. This allows for sufficient volume in the reaction layer and reduces the number of layers, resulting in excellent cost performance and efficient heating of the reaction layer by the heating layer.

[0033] (Reaction layer) In the structure of the present invention, the reaction layer comprises a substrate, a support, and an adsorbent that adsorbs and desorbs carbon dioxide supported on the support.

[0034] The above-mentioned substrate is a basic component that constitutes the reaction layer. The portion of the substrate that comes into contact with the carbon dioxide-containing gas is covered with a carrier, and the adsorbent is supported on this carrier. Alternatively, the substrate may also serve as the carrier, and the adsorbent may be supported on this carrier-containing substrate. The material constituting the above substrate is not particularly limited, but examples include at least one selected from the group consisting of carbon, metal, and high thermal conductivity ceramics.

[0035] The structure of the base is not particularly limited, but it may be a corrugated structure in which multiple layers of flat and corrugated plates are laminated, the contact portions are bonded or joined to form through holes, and a frame is arranged on the side of these laminates, or it may be a honeycomb structure in which multiple through holes that serve as passages for gas containing carbon dioxide are arranged in parallel in the direction in which the through holes extend, separated by partition walls.

[0036] When the base material consists of a corrugated structure, the flat or corrugated plates may be made of metal plates, or they may be made by weaving fibers made of metal or highly thermally conductive ceramics to form a flat or corrugated shape, or they may be made by using thread-like material and weaving it into a mesh structure to form a flat or corrugated shape. In this case, the metal plate used should preferably be porous or have its surface area increased by etching or similar means. Similarly, fibrous or mesh structures made of metal or high thermal conductivity ceramics should also preferably be porous or have their surface area increased by etching or similar means.

[0037] When the corrugated structure member is made of metal, it is desirable to coat the flat, fibrous, or thread-like metal surface with a wash coat or the like and then support the adsorbent on this support. Examples of supports include Al2O3, TiO2, SiO2, ZrO2, zeolite, and carbon. In practice, these can be used to create supports made of the above materials by using a suspension in which the oxide is dispersed in a dispersion medium such as an inorganic sol, an organic binder, or a mixture thereof, attaching the suspension to the surface of a substrate, and then drying and calcining it.

[0038] When the corrugated structure member is made of a highly thermally conductive ceramic, a carrier may be coated on the fibrous or filamentous metal surface with a wash coat or the like, and the adsorbent may be supported on this carrier, or the substrate may also serve as the carrier, and the adsorbent may be supported directly on the substrate.

[0039] Examples of metals that make up corrugated structural components include iron, aluminum, copper, nickel, cobalt, chromium, and alloys thereof.

[0040] Examples of high thermal conductivity ceramics that make up corrugated structural members include aluminum nitride, silicon carbide, silicon nitride, and alumina.

[0041] If the reaction layer is composed of a honeycomb structure, the material of the honeycomb structure is not particularly limited, but metal, carbon, or high thermal conductivity ceramic is preferable. Examples of high thermal conductivity ceramics that make up a honeycomb structure include aluminum nitride, silicon carbide, silicon nitride, and alumina. Examples of metals that make up a honeycomb structure include iron, aluminum, copper, nickel, cobalt, chromium, and alloys thereof. The material for the honeycomb structure may be a mixture of metal and ceramic.

[0042] When the material of the honeycomb structure is carbon, a carrier may cover the surface of the partition wall separating the through-holes of the honeycomb structure, and an adsorbent may be supported on this carrier. However, it is desirable that the partition wall separating the through-holes of the honeycomb structure has a porous structure with a high specific surface area, and that the adsorbent is supported directly on this porous, high specific surface area partition wall without the need for a carrier.

[0043] Examples of adsorbents supported in the reaction layer include amine compounds. Specific amine compounds include polyethyleneimine, monoethanolamine, diethanolamine, triethanolamine, tetraethyleneaminepentamine, methyldiethanolamine, dibutylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, hexaethylenediamine, benzylamine, metaxylenediamine, polyethyleneimine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0044] For example, the amine compound may be supported on a support by passing an aqueous solution of the amine compound through the through-holes of the honeycomb structure, or by immersing the honeycomb structure in an aqueous solution of the amine compound. Alternatively, aqueous solutions of these amine compounds or alcohol solutions may be mixed with particles constituting the support, allowed to thoroughly impregnate the particles, and then the septum inside the reaction layer may be covered with the amine-containing support to remove water and alcohol. A loading process in which an amine compound is impregnated into the above-mentioned partition wall results in a carbon dioxide adsorbent having amine-derived residues on the surface of the partition wall.

[0045] (heating layer) The heating layer consists of a plate-shaped heat transfer element or a heat transfer element having one or more through holes that serve as flow passages for a heating fluid, and is bonded to the reaction layer. The heating layer described above preferably consists of at least one material selected from the group consisting of carbon, metal, and ceramic.

[0046] The type of metal constituting the heating layer described above is not particularly limited, but those with high thermal conductivity are preferred, such as aluminum, nickel, chromium, cobalt, tungsten, copper, iron, and their alloys. Ceramics with high thermal conductivity are also preferred, such as aluminum nitride, silicon carbide, silicon nitride, and alumina.

[0047] When using metal, a plate-shaped heat transfer element without through holes may be used as is, and heat may be transferred to the reaction layer through the plate-shaped heat transfer element by contact with a heat transfer medium such as water vapor. However, it is preferable to use a metal heat transfer element that has one or more through holes that serve as flow passages for the heating fluid.

[0048] The structure of a metal heat transfer body having multiple through holes is not particularly limited, but it is preferable that it is made by laminating and joining flat plates and corrugated or plate-like bodies with multiple regularly spaced grooves, or that it is a honeycomb structure made of a mixture of ceramic or organic material with metal used as a filler.

[0049] When using carbon or ceramics, a heat transfer body having multiple through-holes can be obtained by extruding a raw material composition, which is a mixture of ceramic powder or carbon powder, a binder, and a dispersion medium such as water, and then firing it.

[0050] (Adhesive layer) The adhesive that forms the bonding layer between the reaction layer and the heating layer is not particularly limited, but inorganic adhesives, heat-resistant organic synthetic adhesives, carbon-based adhesives, and metal-based adhesives such as solder can be used. Examples of inorganic adhesives include those primarily composed of silica-alumina, silica, alumina, and zirconia. Examples of heat-resistant organic synthetic adhesives include silicone adhesives, phenolic resin adhesives, polyimide adhesives, and polybenzimidazole adhesives. To increase thermal conductivity, adhesives containing ceramic powders such as alumina, aluminum nitride, boron nitride, and silicon nitride, or metal powders such as aluminum, copper, and nickel, can be used.

[0051] The heating fluid used to heat the heat transfer element is not particularly limited and can include nitrogen, air, or steam, but steam, which is used in power plants and other factories, is preferable because it is an inexpensive heating source.

[0052] The structure of the present invention has a structure in which a reaction layer and a heating layer are alternately stacked, and its external shape is not particularly limited, but a rectangular prism shape is preferable, and the shapes of the reaction layer and heating layer are also preferably rectangular prism shapes (cuboid shapes).

[0053] Furthermore, a structure is desirable in which the honeycomb structure and the heat transfer elements are stacked so that the flow paths of the honeycomb structure constituting the reaction layer intersect with the flow paths of the heat transfer elements constituting the heating layer.

[0054] Figure 1 is a schematic perspective view showing an example of the structure of the present invention. As shown in Figure 1, the structure 100 of the present invention consists of a ceramic honeycomb structure (reaction layer) 20, which has a large number of through-holes 21 that serve as flow passages for a gas containing carbon dioxide arranged in the longitudinal direction separated by a partition wall 22, and a heat transfer body 10, which has a large number of through-holes 11 that serve as flow passages for a heat source such as water vapor, arranged in the direction in which the through-holes 11 extend, separated by a partition wall 12, and the honeycomb structure 20's flow passages (through-holes 21) and the heat transfer body 10's flow passages (through-holes 11) intersecting.

[0055] Furthermore, an adhesive layer 30 is formed between the honeycomb structure 20 and the heat transfer element 10, and this adhesive layer 30 adheres the honeycomb structure 20 and the heat transfer element 10 together.

[0056] In the structure 100 shown in Figure 1, the honeycomb structure 20 has through holes 21 exposed on the front left side and the back right side, and the heat transfer element 10 has through holes 11 exposed on the front right side and the back left side. Therefore, in the honeycomb structure 20, gases containing carbon dioxide flow from the front left to the back right or in the opposite direction, and in the heat transfer element 10, gases containing water vapor etc. flow from the front right to the back left or in the opposite direction. Since the two flow paths intersect at a right angle, it is easy to circulate two types of fluids (gases), and heat from the heat transfer element 10 can be efficiently transferred to the honeycomb structure 20.

[0057] In the structure 100 shown in Figure 1, the honeycomb structure 20 that constitutes the structure 100 is made up of one honeycomb structure 20, but multiple small honeycomb structures may be combined and bonded together to form a honeycomb structure, and the heat transfer element 10 may also be made up of multiple small heat transfer elements combined and bonded together to form a heat transfer element.

[0058] In the structure of the present invention, the width of the reaction layer between the two heating layers is 20 to 100 cm, but preferably 30 to 90 cm. The volume of this reaction layer is preferably 200 to 1000 L (liters). Furthermore, the volume ratio of the reaction layer to the total volume (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) is 0.6 to 0.9, but it is preferable that it be 0.7 to 0.85.

[0059] As described above, by setting the width and volume ratio of the reaction layer, it is possible to obtain a sufficient volume for the reaction layer and reduce the number of layers, resulting in excellent cost performance and efficient heating of the reaction layer by the heating layer.

[0060] In the structure shown in Figure 1, the end face where the through-holes of the honeycomb structure are exposed is rectangular, and in this case, the length of one side is preferably 20 to 100 cm. When the end face of the honeycomb structure is rectangular and the length of one side is 20 to 100 cm, the surface area inside the honeycomb structure becomes sufficiently large, allowing a large amount of adsorbent to be carried, and heat from the heating layer is easily transferred to the adsorbent.

[0061] In the structure of the present invention, the shape of the through-holes constituting the honeycomb structure is preferably rectangular at the end face and rectangular overall, as shown in Figure 1, but it may also be triangular or hexagonal. The shapes of the through-holes may differ, but it is preferable that they are all the same.

[0062] In the structure of the present invention, it is desirable that the thickness of the partitions of the honeycomb structure be uniform. Specifically, it is desirable that the thickness of the partitions of the honeycomb structure be 0.1 to 1.0 mm, and more preferably 0.2 to 0.5 mm. When the thickness of the partitions of the honeycomb structure is thin, the surface area increases, making it possible to support a larger amount of catalyst.

[0063] When the thickness of the partition walls of the honeycomb structure is set as described above, a larger amount of adsorbent can be supported, allowing for the adsorption and absorption of a large amount of carbon dioxide. Additionally, a large amount of heat can be rapidly supplied from the heating layer, thus enabling efficient adsorption and desorption of carbon dioxide.

[0064] In the structure of the present invention, the density of through-holes in a cross section perpendicular to the longitudinal direction of the honeycomb structure is 46.5 to 155 holes / cm². 2 (300~1000 pieces / inch 2 It is preferable that the number be 62-124 / cm². 2 (400~800 pieces / inch 2 This is more desirable because it increases the surface area, allowing it to support a larger amount of adsorbent. The thermal conductivity of the honeycomb structure, which is the reaction layer, should preferably be between 15 and 300 W / m·K.

[0065] In the structure of the present invention, the honeycomb structure that forms the reaction layer is stacked in 1 to 20 layers, and it is desirable that the reaction layer is sandwiched between the heating layers. The structure of the present invention is configured in this way, and by flowing a heat source such as steam through the heating layer and heating the reaction layer, carbon dioxide that has flowed through the reaction layer, been adsorbed and absorbed, can be efficiently desorbed and released. Furthermore, since the heating layer is provided separately from the reaction layer where carbon dioxide deadsorption takes place, the heat source and the adsorbent in the reaction layer do not come into direct contact, inexpensive steam can be used as the heat source for the heating layer, and there is no need to evaporate the water adsorbed on the reaction layer due to this steam, thus enabling efficient and low-cost adsorption and desorption of carbon dioxide. The honeycomb structure shown in Figure 1 is made of high thermal conductivity ceramics or carbon, but it may also be made of metal.

[0066] The heating layer shown in Figure 1 is assumed to be made of metal, and is constructed by joining together flat plates and corrugated plates. The shape of the through-holes at the end faces will vary depending on the shape of the corrugated plates, but a triangular prism shape or a curved surface approximating a triangular prism, as shown in Figure 1, is desirable. When the heating layer is made of carbon or ceramic, the shape of the through-holes in the heating layer can be a rectangular prism, triangular prism, hexagonal prism, etc., similar to the shape of the through-holes in the honeycomb structure described above.

[0067] The density of through-holes in a cross-section perpendicular to the longitudinal direction of the heated layer is 0.005 to 77.5 holes / cm². 2 (0.03~500 pieces / inch 2 It is preferable that the density be 0.15 to 46.5 particles / cm². 2 (1~300 pieces / inch 2 This is more desirable because it increases the surface area, allowing a large amount of heat, such as water vapor, to be transferred to the honeycomb structure quickly and efficiently.

[0068] In the structure of the present invention, the width of the heating layer is preferably 2 to 20 cm, and more preferably 3 to 18 cm. Furthermore, the volume of the heating layer is preferably 20 to 200 L (liters). Also, the thermal conductivity of the heating layer is preferably 15 to 300 W / m·K.

[0069] [Method for manufacturing the structure] Next, we will describe the method for manufacturing the above structure. When manufacturing the above structure, the following steps are performed to produce a structure in which the honeycomb structure and the heat transfer element are stacked. The following description will focus on the case where carbon is used as the material constituting the honeycomb structure and metal is used as the material constituting the heat transfer element. However, as mentioned above, the materials constituting the honeycomb structure and heat transfer element are not limited to the materials described above, nor are the manufacturing methods limited to the methods described below.

[0070] In manufacturing the structure of the present invention, first, the honeycomb structure and the heat transfer element are manufactured, and then the manufactured honeycomb structure and the heat transfer element are bonded together. When manufacturing a honeycomb structure using carbon as a substrate, or a substrate and support, for example, first, a raw material composition is prepared by mixing and kneading carbon precursor particles, high thermal conductivity filler particles, pore-forming material, binder, dispersion medium, etc.

[0071] Figure 2A is a schematic cross-sectional view showing a honeycomb molded body produced by the manufacturing method of the structure of the present invention, and Figure 2B is a cross-sectional view of the honeycomb molded body shown in Figure 2A along line AA. After the above process, the raw material composition is extruded to produce a honeycomb molded body 40 having a shape almost identical to a honeycomb structure with numerous through holes 41 and partition walls 42 separating the through holes 41, as shown in Figures 2A and 2B. Furthermore, the carbon precursor is carbonized by firing at a temperature of about 600 to 1000°C under an inert gas such as nitrogen.

[0072] Examples of carbon precursors include non-graphitizable carbons such as cellulose fibers and phenolic resins, easily graphitizable carbons such as mesophase pitch, coke, polyvinyl chloride, polyimide, and polyacrylonitrile (PAN); and mixtures thereof. These carbon precursors may be used individually or in combination of two or more. Among these, phenolic resins, PAN, and coke are preferred.

[0073] Examples of high thermal conductivity fillers include aluminum, copper, natural graphite (scaly), and aluminum nitride. By adding these to the raw material composition in particulate form (powder form) as described above, the thermal conductivity of the honeycomb structure can be increased.

[0074] When manufacturing a honeycomb structure, by heating a honeycomb molded body containing a carbon precursor as described above to carbonize it, and then performing an activation treatment, it is possible to manufacture a honeycomb structure with a higher specific surface area, and to support a large amount of adsorbent on the honeycomb structure.

[0075] Methods of activation treatment include gas activation treatment and chemical activation treatment. Gas activation treatment is a method in which the carbide is heated to a predetermined temperature and then activated by supplying an activation gas. As the activation gas, water vapor, air, carbon dioxide, oxygen, combustion gas, and mixtures thereof can be used. The activation treatment may be performed when firing the molded body at a temperature of about 800 to 1000°C, by supplying the above-mentioned activation gas after the predetermined temperature has been reached, or when processing at a temperature higher than 1000°C, by supplying the activation gas and performing the activation treatment.

[0076] Chemical activation treatment is a method in which, when preparing a raw material composition, an activator is added to the raw material composition, a honeycomb molded body is produced, and then the body is fired to simultaneously perform carbonization and activation treatment. In the present invention, it is desirable to use an alkali metal compound as the activator. The alkali metal compound is not particularly limited, but examples include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, alkali metal carbonates such as potassium carbonate and sodium carbonate, and alkali metal sulfates such as potassium sulfate and sodium sulfate. Among these, potassium hydroxide and sodium hydroxide are preferred. Other activators besides alkali metal compounds may be included as activators. Examples of other activators include phosphoric acid, sulfuric acid, calcium chloride, zinc chloride, potassium sulfide, and the like. The raw material composition may further contain molding aids, etc.

[0077] The binder is not particularly limited, but examples include pitch, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyethylene glycol, phenolic resin, epoxy resin, etc., and two or more may be used in combination. Among these, pitch, which readily turns into carbon during firing, is preferred.

[0078] The pore-forming agent is not particularly limited, but examples include acrylic resin and starch. Pore-forming agents are substances used to introduce pores into the interior of honeycomb structures during their manufacture.

[0079] The molding aids are not particularly limited, but include ethylene glycol, dextrin, fatty acids, fatty acid soaps, polyalcohols, etc., and two or more may be used in combination.

[0080] The dispersion medium is not particularly limited, but examples include water, organic solvents such as benzene, and alcohols such as methanol, and two or more may be used in combination.

[0081] When preparing the raw material composition, mixing and kneading is desirable. This may be done using a mixer, attritor, etc., or kneading using a kneader, etc.

[0082] Next, the honeycomb molded body is dried, then heated and fired to carbonize it, thereby producing a honeycomb structure made of carbon (graphite). In the drying process, the honeycomb molded body is dried using dryers such as microwave dryers, hot air dryers, dielectric dryers, vacuum dryers, vacuum dryers, and freeze dryers. Next, it is heated and baked at 600-1000°C. Heating and firing are usually carried out in a nitrogen or argon atmosphere, but as mentioned above, activation can also be performed simultaneously by using steam, air, carbon dioxide, oxygen, combustion gases, or mixtures thereof.

[0083] (Manufacturing of heat transfer devices) The method for manufacturing a metal heat transfer body having multiple through holes is not particularly limited, but the following methods are possible. Figure 3A is a schematic cross-sectional view showing one step of the manufacturing method for the heat transfer body described above, and Figure 3B is a schematic cross-sectional view showing the heat transfer body obtained by the manufacturing method described above. First, a flat steel plate 51 and a corrugated steel plate 52 made of stainless steel or the like are prepared and stacked (see Figure 3A). Next, the stacked flat steel plate 51 and corrugated steel plate 52, which are fixed in place with a fastener (not shown), are placed in a vacuum furnace or the like, and the contact parts are joined by applying a predetermined pressure with a diffusion bonding jig and heating. After this, a flat plate is joined to the side to obtain a heat transfer body 10 having through holes 11 and partition walls 12 as shown in Figure 3B.

[0084] Furthermore, by placing a masking member on one side of a flat metal plate made of stainless steel or the like, and etching using the masking member as a mask, a flat metal plate with grooves forming fluid passages (through holes) can be obtained. Next, the flat metal plate with grooves and a flat metal plate without grooves are stacked and placed in a vacuum furnace or the like in the same manner as above, and by applying a predetermined pressure with a diffusion bonding jig and heating, the contact parts are joined, and a heat transfer body having through holes and partitions can be obtained.

[0085] (Bonding process between heat transfer element and honeycomb structure) The manufactured heat transfer element and honeycomb structure can be bonded alternately using the aforementioned high thermal conductivity inorganic adhesive, organic synthetic adhesive, carbon-based adhesive, or metal-based adhesive, and the flow paths of the honeycomb structure constituting the reaction layer and the flow paths of the heat transfer element constituting the heating layer intersect, thereby producing a structure 100 as shown in Figure 1.

[0086] (Carbon dioxide capture device) The carbon dioxide recovery device of the present invention is characterized by comprising the above-described structure. Figure 4 is a schematic diagram illustrating a carbon dioxide capture device equipped with the structure of the present invention. The carbon dioxide capture device 200 of the present invention comprises two structures, a first structure 211 and a second structure 212. The carbon dioxide capture device 200 may comprise three or more structures, but here the system will be described as a device comprising two structures. Although not shown in the diagram, the first structure 211 and the second structure 212 installed in this carbon dioxide capture device 200 are stacked so that multiple reaction layers and heating layers intersect with each other.

[0087] The carbon dioxide (CO2)-containing gas 210 generated from the generator, etc., passes through a denitrification device, dust collector, desulfurization device, precooler, etc. (not shown) before being introduced into the reaction layer of the first structure 211 or the second structure 212. The piping through which the carbon dioxide (CO2)-containing gas 210 passes is equipped with switching valves 240, 241, 250, and 251, and by switching these valves, the carbon dioxide (CO2)-containing gas 210 is selectively introduced into either structure. After leaving the reaction layer of the first structure 211 or the second structure 212, the carbon dioxide (CO2)-containing gas 210 passes through a chimney 213 and is discharged as exhaust gas 214.

[0088] On the other hand, the piping through which the steam gas 230, which contains the heat source, passes is equipped with switching valves 244, 245, 247, and 248. The steam gas 230 is introduced into the heating layer of either the first structure 211 or the second structure 212, passes through the heat exchanger 231, and is discharged as exhaust gas 232. A gas 233, consisting of air or the like, is introduced into the heat exchanger 231. The gas 233, heated by the steam gas 230 that has left the heating layer, is used as steam preheating gas 234 and preheats the steam via a heat exchanger (not shown). This gas may also be used for other purposes, such as heating specific equipment.

[0089] The first structure 211 or the second structure 212 is also designed to incorporate carbon dioxide (CO2) capture gas 220. The piping for carbon dioxide (CO2) capture gas 220 is equipped with switching valves 246, 249, 242, and 243, and the carbon dioxide desorbed and released in either reaction layer is stored as carbon dioxide (CO2) 222 by various methods via pump 221.

[0090] When operating the carbon dioxide recovery device of the present invention, first, carbon dioxide (CO2)-containing gas 210 is introduced into the reaction layer of the first structure 211, and after carbon dioxide is adsorbed and absorbed, it is discharged through the chimney 213. When the reaction layer of the first structure 211 becomes saturated, the switching valves 240, 241, 250, and 251 are operated, and carbon dioxide (CO2)-containing gas 210 is introduced into the reaction layer of the second structure 212, and similarly, after carbon dioxide is adsorbed and absorbed, it is discharged through the chimney 213.

[0091] While carbon dioxide (CO2)-containing gas 210 is introduced into the second structure 212, water vapor gas 230 is introduced into the heating layer of the first structure 211, which has sufficiently adsorbed and absorbed carbon dioxide. The reaction layer of the first structure 211, heated by the heating layer, desorbs and releases carbon dioxide. The desorbed and released carbon dioxide, along with carbon dioxide recovery gas 220, is introduced into pump 221. After exiting pump 221, it is stored as carbon dioxide (CO2) 222, and carbon dioxide generated by generators, etc., is recovered.

[0092] While the carbon dioxide recovery operation described above is being carried out in the first structure 211, carbon dioxide is sufficiently adsorbed and absorbed in the reaction layer of the second structure 212. Therefore, by operating the switching valves 240, 241, 250, and 251, the carbon dioxide (CO2)-containing gas 210 is reintroduced into the first structure 211. Meanwhile, in the second structure 212, the carbon dioxide recovery operation is carried out in the same manner as in the first structure 211. By alternately repeating the above operations of carbon dioxide adsorption, absorption, desorption, and release between the first structure 211 and the second structure 212, carbon dioxide can be recovered efficiently.

[0093] (Examples) The following are examples that more specifically disclose embodiments of the present invention. However, the present invention is not limited to these embodiments.

[0094] (Example 1)

[0095] (Manufacture of honeycomb structure) 25.5 parts by weight of polyacrylonitrile (PAN), 4.1 parts by weight of an organic binder (methyl cellulose), 55.2 parts by weight of aluminum metal (average particle diameter 10 μm), 1.4 parts by weight of a lubricant (Unirub manufactured by NOF Corporation), and 13.8 parts by weight of water were added and kneaded to prepare a raw material composition.

[0096] Next, using a mold for manufacturing a honeycomb structure, extrusion molding of the raw material composition was performed to produce a honeycomb molded body having the same structure as the honeycomb structure.

[0097] Then, the honeycomb molded body was dried using a microwave dryer, carried into a heating furnace, and fired and carbonized under heating conditions of 1000 °C for 1 hour in a nitrogen atmosphere.

[0098] Next, the obtained honeycomb-structured member was heated at 900 °C under steam and subjected to an activation treatment to increase the surface area.

[0099] Thereafter, an aqueous solution of an amine compound containing monoethanolamine was prepared, and the honeycomb structure after completion of the carbonization step was immersed in the aqueous solution of the amine compound to support 30 g / L of the amine compound on the partition walls of the honeycomb structure.

[0100] The obtained honeycomb structure supporting the amine compound has, with respect to the shape of the end face where the through holes are exposed, a length (width) in the stacking direction of 8.9 cm, a length of the bonding surface of 10 cm, a length in the through hole direction of 10 cm, and a through hole density of 155 pieces / cm 2 (1000 cpsi), and the thickness of the partition wall was 0.2 mm. The length in the stacking direction of the honeycomb structure becomes the width of the reaction layer.

[0101] Also, the obtained honeycomb structure contains 43% by weight of aluminum, and the density is 2.3 g / cm 3 , and the thermal conductivity was 20 W / m·K.

[0102] (Manufacture of heat transfer body) A flat stainless steel plate with a thickness of 0.5 mm and a corrugated stainless steel plate with a thickness of 0.5 mm, a wave pitch of 2 mm, and a valley depth / peak height of 2 mm were prepared. The two were then alternately stacked, placed in a vacuum furnace, and the contact points were joined by applying pressure and heating using a diffusion bonding jig. Plate-like bodies were then joined to the sides to produce a heat transfer body 10 having through holes 11 and partition walls 12 as shown in Figure 3B. Regarding the shape of the end face with the exposed through-hole, the heat transfer element had a width in the stacking direction (vertical): 0.55 cm, a length of the adhesive surface (horizontal): 10 cm, and a length in the direction of the through-hole: 10 cm. The thermal conductivity of the heat transfer material was 16.3 W / m·K.

[0103] (Lamination, adhesion process) An inorganic adhesive made of silica alumina was applied to the bonding surface of one honeycomb structure 20 manufactured by the above process and to the bonding surface of two heat transfer elements 10. The two structures were then stacked and bonded together so that the heat transfer elements 10 were positioned on the outside of both structures, and the adhesive was cured by heating to 150°C, thus completing the manufacture of the laminate of the present invention.

[0104] The width of the reaction layer (honeycomb structure) that constituted the structure manufactured in this Example 1 was 8.9 cm, and the volume ratio of the reaction layer (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) was 0.89.

[0105] (Comparative Example 1) The structure was manufactured in the same manner as in Example 1, except that the width of the reaction layer (honeycomb structure) constituting the manufactured structure was set to 5 cm, the width of the heat transfer element was set to 2.5 cm, and the volume ratio of the reaction layer (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) was set to 0.5.

[0106] (Comparative Example 2) The structure was manufactured in the same manner as in Example 1, except that the width of the reaction layer (honeycomb structure) constituting the manufactured structure was set to 9.4 cm, the width of the heat transfer element was set to 0.3 cm, and the volume ratio of the reaction layer (volume of the reaction layer / (volume of the reaction layer + volume of the heating layer)) was set to 0.94.

[0107] (Carbon dioxide adsorption / desorption test) In the honeycomb structure comprising the manufactured Example 1 and Comparative Examples 1-2, piping for circulating a gas containing carbon dioxide was connected to the end face where the through-holes were exposed, and piping for circulating a heat source containing water vapor was connected to the end face where the through-holes of the heat transfer element were exposed.

[0108] Next, a gas containing 5% by volume of carbon dioxide at 40°C was introduced into the through-holes of the honeycomb structure at a flow rate of SV (space velocity) = 5000 / hr, and the flow was continued until the adsorbent in the structure was saturated. To assess the adsorption and absorption state, the gas that passed through the honeycomb structure was analyzed with a gas analyzer, and saturation was determined when the carbon dioxide concentration, reduced by adsorption and absorption by the adsorbent, returned to its initial concentration. The time to reach saturation was 248 seconds for Example 1, 136 seconds for Comparative Example 1, and 260 seconds for Comparative Example 2.

[0109] Subsequently, a 120°C gas containing water vapor was introduced into the through-holes of the heat transfer element, and nitrogen gas was introduced into the through-holes of the honeycomb structure at an SV (space velocity) of 1000 / hr to desorb and release carbon dioxide. During this process, the amount of desorbed and released carbon dioxide was measured using a gas analyzer, and the desorbing and release process was deemed complete when the carbon dioxide concentration fell to 0.1% by volume or less. As a result, the detachment and release times were 307 seconds for Example 1, 170 seconds for Comparative Example 1, and 762 seconds for Comparative Example 2.

[0110] Thus, in Example 1, a large amount of carbon dioxide could be adsorbed and desorbed in a short time, whereas in Comparative Example 1, the amount of carbon dioxide adsorbed was small, resulting in frequent switching between adsorption and desorption, and in Comparative Example 2, it took a long time for the adsorbed carbon dioxide to be desorbed. In this embodiment, the evaluation was performed using a structure in which two heat transfer elements 10 were bonded to both sides of a single honeycomb structure 20. However, since the same structure can be used when multiple honeycomb structures 20 and heat transfer elements 10 are stacked alternately, similar results can be expected. [Explanation of Symbols]

[0111] 10 Heat transfer element 11 Through hole 12 Bulkhead 20 Honeycomb Structure 21 Through hole 22 Bulkhead 30 Adhesive layer 40 Honeycomb molded body 41 Through hole 42 Bulkhead 51 Flat steel plate 52 Corrugated steel sheet 100 structures 200 Carbon Dioxide Capture Devices 210 Carbon dioxide (CO2) containing gases 211 First structure 212 Second structure 213 Chimney 214, 232 exhaust gas 220 Carbon Dioxide (CO2) Capture Gas 221 Pump 222 Carbon Dioxide (CO2) 230 Water vapor gas 231 Heat exchanger 233 Gas 234 Steam Preheating Gas 240, 241, 242, 243, 244, 245 Switching valve 246, 247, 248, 249, 250, 251 Switching valve

Claims

1. A carbon dioxide recovery structure comprising a reaction layer consisting of a substrate, a support, and an adsorbent for adsorbing and desorbing carbon dioxide supported on the support, and a heating layer for heating the reaction layer, stacked alternately, The adsorbent is an amine compound, The structure is characterized in that the volume ratio of the reaction layers (total volume of the reaction layers / (total volume of the reaction layers + total volume of the heating layers)) is 0.6 to 0.

9.

2. The structure according to claim 1, wherein the substrate constituting the reaction layer is a honeycomb structure in which a plurality of through-holes, which serve as flow passages for a gas containing carbon dioxide, are arranged in parallel in the direction in which the through-holes extend, separated by partition walls.

3. The honeycomb structure is the substrate and the carrier according to claim 2.

4. The structure according to claim 2 or 3, wherein the thermal conductivity of the honeycomb structure is 15 to 300 W / m·K.

5. The structure according to any one of claims 2 to 4, wherein the heating layer is made of a plate-shaped heat transfer material or a heat transfer material having one or more through holes that serve as flow passages for a heating fluid, and is bonded to the reaction layer in a state of close contact with the reaction layer.

6. The structure according to claim 5, wherein the honeycomb structure and the heat transfer element are stacked such that the flow passage of the honeycomb structure constituting the reaction layer and the flow passage of the heat transfer element constituting the heating layer intersect.

7. The structure according to any one of claims 1 to 6, wherein the substrate comprises at least one selected from the group consisting of carbon, metal, and high thermal conductivity ceramic.

8. A carbon dioxide recovery device characterized by comprising the structure described in any one of claims 1 to 7.

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