CO2 separation and recovery system

Abstract

The present invention provides a CO2 separation and recovery device that allows for control of the amount of adsorbent and pressure loss. [Solution] The CO2 separation and recovery apparatus 1 according to the present invention separates and recovers CO2 by physical adsorption, and comprises a tank 2 filled with a first adsorbent that adsorbs the CO2, wherein the tank 2 is divided into multiple stages by a mesh-like structure 31 with a mesh opening smaller than the size of the first adsorbent 4, and each of the multiple stages is filled with the first adsorbent 4.

Description

[Technical Field] 【0001】 This invention relates to a carbon dioxide (CO2) separation and recovery device. [Background technology] 【0002】 Regarding the reduction of CO2 emissions, while progress is being made in the development of electrical appliances and other products that do not emit CO2, there are also products and equipment for which CO2 emissions are unavoidable. For example, gas engines, gas boilers, and drying ovens that use methane or natural gas as fuel generate large amounts of CO2. For instance, the CO2 concentration in the exhaust gas from these devices is about 10%. Given the scale of the exhaust gas volume, physical adsorption methods are considered appropriate for separating and recovering CO2 from these devices. Examples of physical adsorption methods include pressure swing adsorption (PSA) and thermal swing adsorption (TSA). 【0003】 Regarding apparatuses using physical adsorption, for example, Patent Document 1 describes an adsorption tower having a packed adsorbent bed inside a vertical cylindrical tower body, with the upper and lower parts separated by a mesh plate to prevent the escape of adsorbent particles. This adsorption tower has a gas outlet pipe at the top and a gas inlet pipe at the bottom. When separating and recovering CO2 by physical adsorption, apparatuses with adsorption towers of this configuration (CO2 separation and recovery apparatuses) are often used. 【0004】 Patent Document 1 describes a method for filling the adsorbent-packed bed of an adsorption tower with the above-described configuration with adsorbent. In this method, first, adsorbent is filled into the adsorbent-packed bed by gravity from a pressurized filling hopper. Then, the method makes it possible to supply adsorbent from the pressurized filling hopper. Then, pressurized gas is sent into the tower body from a blower connected to the gas inlet pipe to pressurize it. At this time, the filling hopper itself is also pressurized with adsorbent inside. After that, the gas is released by opening a pressure reducing valve connected to the gas outlet pipe to reduce the pressure and perform depressurized fluidized filling. Patent Document 1 states that by doing so, the ineffective volume in the adsorption tower can be reduced and the utilization rate of the adsorbent can be increased. [Prior art documents] [Patent Documents] 【0005】 [Patent Document 1] Japanese Patent Application Publication No. 8-89741 [Overview of the Initiative] [Problems that the invention aims to solve] 【0006】 Conventional technologies, including the invention described in Patent Document 1, have packed adsorbent (adsorbent material) as densely as possible into the adsorption tower. However, because the adsorbent material was packed so densely, it was impossible to control the amount of adsorbent material used, and an excessive amount of packing material was sometimes used. In other words, conventional technologies could not use the necessary and sufficient amount of adsorbent material. Furthermore, because conventional technologies packed the adsorbent material so densely, it was impossible to control any unnecessary pressure loss that occurred. 【0007】 This invention has been made in view of the above circumstances. The object of this invention is to provide a CO2 separation and recovery device that can control the amount of adsorbent and the pressure loss. [Means for solving the problem] 【0008】 The CO₂ separation and recovery device according to the present invention that solves the above problems is a CO₂ separation and recovery device that separates and recovers CO₂ by a physical adsorption method, and includes a tank filled with a first adsorbent that adsorbs the CO₂. The tank is partitioned into multiple stages by a mesh-like structure with a mesh size smaller than the size of the first adsorbent, and the first adsorbent is filled in each of the multiple stages. 【Effect of the Invention】 【0009】 According to the present invention, it is possible to provide a CO₂ separation and recovery device capable of controlling the amount of the adsorbent and the pressure loss. Problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments. Further features related to the present invention will become apparent from the description of this specification and the attached drawings. 【Brief Description of the Drawings】 【0010】 [Figure 1] It is a schematic diagram for explaining the configuration of the CO₂ separation and recovery device 1 according to the first embodiment. [Figure 2A] It is a schematic diagram for explaining the packed bed 241 (packing area) of the adsorbent 204 in the CO₂ separation and recovery device 200 according to the prior art. [Figure 2B] It is a schematic diagram for explaining the packed bed 41 (packing area) of the adsorbent (first adsorbent 4) in the CO₂ separation and recovery device 1 according to the first embodiment. [Figure 3] It is an explanatory diagram for explaining a preferable arrangement example of the adsorbent filling container 3 in the first embodiment. [Figure 4] It is an explanatory diagram for explaining another preferable arrangement example of the adsorbent filling container 3 in the first embodiment. [Figure 5] It is an explanatory diagram for explaining another preferable arrangement example of the adsorbent filling container 3 in the first embodiment. [Figure 6] It is a conceptual diagram of the configuration of the packed bed. [Figure 7] It is a conceptual explanatory diagram of the capture radius r. [Figure 8] It is a conceptual explanatory diagram of the total capture cross-sectional area. [Figure 9] It is a conceptual explanatory diagram showing the relationship between the inspection volume cross-section of the packed layer and the total cross-sectional area contributing to the capture of molecules. [Figure 10A] It is a conceptual diagram showing a model in which the packed layer 241 (packing area) of the adsorbent in the tank 102 is densely packed with the adsorbent. [Figure 10B] It is a conceptual diagram showing a model in which the adsorbent is filled in the adsorbent filling container 3 at a predetermined filling rate and a plurality of them are arranged in the packed layer 41 (packing area) of the adsorbent in the tank 2. [Figure 11] It is a graph showing an example of the change over time of the amount of CO₂ adsorbed in the adsorbent. [Figure 12] It is a schematic diagram for explaining the configuration of the CO₂ separation and recovery device 1 according to the second embodiment. [Figure 13] It is a schematic diagram showing an example of the configuration of the adsorbent filling container 3 in the second embodiment. [Figure 14] It is a schematic diagram for explaining the configuration of the CO₂ separation and recovery device 1 according to the third embodiment. [Figure 15] It is an explanatory diagram for explaining an example of the combustion process. 【Embodiments for Carrying Out the Invention】 【0011】 Hereinafter, a CO₂ separation and recovery device according to an embodiment of the present invention will be described while appropriately referring to the drawings. In the following description and drawings, the same reference numerals may be assigned to common configurations, and duplicate descriptions may be omitted. Further, the present invention is not limited to the following embodiments. Furthermore, the description in this specification is merely a typical example and does not limit the claims or application examples in any sense. 【0012】 In the following embodiments, where necessary for convenience, the description will be divided into multiple sections or embodiments. Unless otherwise specified, these are not unrelated, and one may be a modification, detail, or supplementary explanation of part or all of the other. Furthermore, in the following embodiments, when referring to the number of elements (including quantity, numerical value, amount, range, etc.), unless otherwise specified or clearly limited to a specific number in principle, it is not limited to that specific number, and may be greater than or less than that number. 【0013】 Furthermore, in the following embodiments, it goes without saying that the components are not necessarily essential unless otherwise explicitly stated or considered to be fundamentally essential. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc., of the components, etc., it shall include those that are substantially similar or analogous to their shape, etc., unless otherwise explicitly stated or considered to be fundamentally essential. The same applies to the numerical values ​​and ranges mentioned above. In addition, the size and number of each component etc. in the illustrations have been exaggerated or simplified as appropriate to make the illustrations easier to understand. 【0014】 [CO2 separation and recovery device] [First Embodiment] Figure 1 is a schematic diagram illustrating the configuration of the CO2 separation and recovery apparatus 1 according to the first embodiment. The CO2 separation and recovery device 1 separates and recovers CO2 by physical adsorption. As shown in Figure 1, the CO2 separation and recovery device 1 includes a tank 2 filled with a first adsorbent 4 that adsorbs CO2. This tank 2 is divided into multiple sections by a mesh-like structure 31 with mesh openings smaller than the size of the first adsorbent 4, and each of the multiple sections is filled with the first adsorbent 4. A preferred specific embodiment of the CO2 separation and recovery device 1 according to the first embodiment is as follows: 【0015】 Tank 2 has a raw gas inlet 21 into which raw gas containing CO2 is introduced. Tank 2 also has a processed gas discharge 22 into which processed gas from which CO2 has been adsorbed and removed is discharged. Tank 2 has a cylindrical body 23, a tank bottom 24 provided at the lower part of the body 23, and a tank lid 25 provided at the upper part of the body 23. These parts of Tank 2 can be detachably fixed with bolts and nuts (not shown), and when fixed, a sealed internal space can be obtained. The raw gas inlet 21 is provided at the lower part of Tank 2, that is, at the tank bottom 24. The processed gas discharge 22 is provided at the upper part of Tank 2, that is, at the tank lid 25. 【0016】 In the first embodiment, as one way of partitioning the inside of the tank 2 in multiple stages with a mesh-like structure 31, multiple adsorbent-filled containers 3 are used. Multiple adsorbent-filled containers 3 are arranged inside the tank 2. Each of the multiple adsorbent-filled containers 3 is filled with a first adsorbent 4 capable of adsorbing CO2, and has at least a mesh-like structure 31 with a mesh opening smaller than the size of the first adsorbent 4 on its bottom 32. The mesh-like structure 31 can be made of a mesh made of metal wires woven into a network, or a metal plate with many through holes, but is not limited to these. The adsorbent-filled container 3 has a side wall portion 33 to which the bottom portion 32 is fixed. The mesh-like structure 31 can also be used on this side wall portion 33. The entire bottom portion 32 and side wall portion 33 may be made of the mesh-like structure 31, or only a part of them may have the mesh-like structure 31. The side wall portion 33 has any height suitable for filling with the first adsorbent 4. The adsorbent-filled container 3 is filled with the first adsorbent 4 inside the side wall portion 33 and the bottom portion 32, and holds it. The amount of first adsorbent 4 filled inside the adsorbent-filled container 3 can be appropriately adjusted to control the filling rate of the adsorbent-filled container 3. In this embodiment, one adsorbent-filled container 3 having the first adsorbent 4 at a predetermined filling rate is considered as one unit, and multiple such units are arranged. 【0017】 In this embodiment, the packing rate of the first adsorbent 4 in one unit can be arbitrarily adjusted within a range of more than 0% and less than or equal to 100%. However, if the packing rate of the first adsorbent 4 is low, the packing depth of the first adsorbent 4 may become too shallow. In this case, a short circuit may occur in the flow of the raw gas, and an imbalance may occur in the collision between the first adsorbent 4 and the raw gas, potentially resulting in insufficient processing. Conversely, if the packing rate of the first adsorbent 4 is high, the packing depth of the first adsorbent 4 may become too deep. In this case, the pressure loss may increase. Therefore, considering these balances, it is considered preferable to set the packing rate of the first adsorbent 4 to, for example, 48% to 60%, but it is not limited to this range. The packing rate of the first adsorbent 4 will be explained later. 【0018】 In the CO2 separation and recovery apparatus 1 according to the first embodiment, the plurality of adsorbent-filled containers 3 are all arranged sequentially such that their bottoms 32 are perpendicular to the direction of travel of the introduced raw gas containing CO2. In other words, in the CO2 separation and recovery apparatus 1, the plurality of adsorbent-filled containers 3 are all arranged to obstruct the progress of the introduced raw gas containing CO2, ensuring that contact between the raw gas containing CO2 and the first adsorbent 4 is reliably made. With this configuration, the tank 2 is partitioned into multiple stages. 【0019】 Furthermore, the main body 23, bottom 24, and lid 25 of the tank 2, as well as the bottom 32 and side walls 33 of the adsorbent-filled container 3, can be made of any metal, such as stainless steel. The tank 2 and the adsorbent-filled container 3 may have a circular or rectangular cross-sectional shape in the horizontal direction, but are not limited to these. It is preferable to provide a sealing member such as an O-ring or gasket between the inner wall of the tank 2 and the side wall 33 of the adsorbent-filled container 3. It is also preferable to fill the gap between the side wall 33 of the adsorbent-filled container 3 and the inner wall surface of the tank 2 with heat-resistant inorganic fibers such as steel wool or ceramic fibers. Doing so prevents the raw gas containing CO2 from being discharged from the treated gas discharge section 22 without being treated by the first adsorbent 4. In other words, more reliable CO2 adsorption treatment is achieved. 【0020】 Here, with reference to Figures 2A and 2B, the differences between the conventional CO2 separation and recovery apparatus 200 and the CO2 separation and recovery apparatus 1 according to the first embodiment will be explained. Figure 2A is a schematic diagram illustrating the packed bed 241 (packing area) of the adsorbent 204 in the conventional CO2 separation and recovery apparatus 200. Figure 2B is a schematic diagram illustrating the packed bed 41 (packing area) of the first adsorbent 4 in the CO2 separation and recovery apparatus 1 according to the first embodiment. 【0021】 As shown in Figure 2A, in the conventional CO2 separation and recovery device 200, the adsorbent 204 is densely packed into the tank 202, and the packing rate is made as high as possible. In contrast, as shown in Figure 2B, in the CO2 separation and recovery device 1 according to the first embodiment, the first adsorbent 4 is packed into each unit (adsorbent-filled container 3) with a predetermined packing rate, and multiple units are stacked and arranged in the tank 2 (not shown in Figure 2B). In other words, in the CO2 separation and recovery device 1 according to the first embodiment, because of the above configuration, the packing rate (and amount) of the first adsorbent 4 in the entire tank 2 is lower compared to the packing rate (and amount) of the adsorbent 204 in the conventional CO2 separation and recovery device 200. However, in the CO2 separation and recovery device 1 according to the first embodiment, the packing rate of the first adsorbent 4 can be arbitrarily controlled, thereby allowing for active control of pressure loss. Furthermore, while the conventional CO2 separation and recovery device 200 does not allow adjustment of the amount of adsorbent 204 filled, the CO2 separation and recovery device 1 according to the first embodiment allows the first adsorbent 4 to be filled at any filling rate in each unit, thus enabling control of the first adsorbent 4 to a necessary and sufficient amount. 【0022】 Here, Figure 3 is an explanatory diagram illustrating a preferred arrangement example of the adsorbent-filled container 3 in the first embodiment. As shown in Figure 3, this embodiment has an adsorbent-filled container 3 filled with the second adsorbent 5. In other words, in this embodiment, at least one of the multi-stage partitioned stages, specifically at least one of the multiple adsorbent-filled containers 3, can be filled with a second adsorbent 5 capable of adsorbing gas components with a molecular size smaller than CO2, instead of the first adsorbent 4. Examples of gas components with a molecular size smaller than CO2 include water molecules (H2O). The molecular size of H2O is approximately 0.28 nm, and the molecular size of CO2 is approximately 0.330 nm. In addition to these, exhaust gases from gas engines, gas boilers, and drying ovens also contain nitrogen (N2) gas, oxygen (O2) gas, methane (CH4) gas, etc. The molecular size of N2 is approximately 0.364 nm, the molecular size of O2 is approximately 0.35 nm, and the molecular size of CH4 is approximately 0.380 nm. 【0023】 In this embodiment, the first adsorbent 4 should have a pore size capable of adsorbing CO2. The second adsorbent 5 should have a pore size capable of adsorbing gas components with molecular sizes smaller than CO2. By using such a second adsorbent 5, H2O, a gas component with a molecular size smaller than CO2, can be selectively adsorbed. Commercially available adsorbents can be used for the CO2 molecular size selective adsorption adsorbent (first adsorbent 4) and the H2O molecular size selective adsorption adsorbent (second adsorbent 5). For example, the first adsorbent 4 and the second adsorbent 5 can be made from activated carbon, zeolite, silica glass, etc., but the material is not limited to these, as long as it can physically adsorb CO2 and H2O. The first adsorbent 4 and the second adsorbent 5 can be used in the form of powder, granules, or carriers that have any shape such as sphere, cubic, rectangular, cylindrical, or octahedron by solidifying them, but are not limited to these forms. The first adsorbent 4 may be made of a material that can adsorb CO2 and release the adsorbed CO2 by heating it to a predetermined temperature (for example, around 100-120°C). Sodium ferrite is an example of such a material. 【0024】 It is preferable that the adsorbent-filled container 3, which is filled with the second adsorbent 5, be positioned at least upstream of the adsorbent-filled container 3, which is filled with the first adsorbent 4, in the direction of travel of the raw gas containing CO2 introduced into the tank 2. For example, the adsorbent-filled container 3, which is filled with the second adsorbent 5, can be positioned closest to the raw gas introduction section 21 (see Figure 1). In this way, since H2O molecules are adsorbed by the second adsorbent 5, which is positioned furthest upstream in the tank 2, it is possible to avoid a situation where H2O molecules are adsorbed by the first adsorbent 4, which is positioned downstream, and the adsorption of CO2 molecules is hindered (a situation in which the CO2 adsorption capacity is reduced). Therefore, in this way, the CO2 adsorption capacity of the first adsorbent 4 can be maintained at a high level. 【0025】 Figure 4 is an explanatory diagram illustrating another preferred arrangement example of the adsorbent-filled container 3 in the first embodiment. As shown in Figure 4, in this embodiment, the first adsorbent 4 can be filled at different rates in each of the multi-stage partitioned sections, specifically in each of the multiple adsorbent-filled containers 3. In this way, adsorbent-filled containers 3 with a high or low rate of the first adsorbent 4 can be placed at the required locations as needed. As a more preferred specific embodiment, as shown in the same figure, the filling rate of the first adsorbent 4 can be set to gradually decrease from the raw gas introduction section 21 (not shown in Figure 4, see Figure 1) to the treated gas discharge section 22 (see Figure 1). For example, as shown in Figure 4, the filling rate can be set to high → medium → low from the raw gas introduction section 21 to the treated gas discharge section 22. The CO2 concentration in the raw gas containing CO2 is high immediately after introduction into tank 2, but as it passes through the adsorbent-filled container 3, which is filled with the first adsorbent 4, CO2 is adsorbed and the concentration decreases. Therefore, multiple adsorbent-filled containers 3 can be arranged so that the filling rate of the first adsorbent 4 decreases as you go downstream, in accordance with the CO2 concentration. In this way, the filling rate of the first adsorbent 4 downstream can be reduced, thereby reducing pressure loss. In addition, the amount of first adsorbent 4 used, which is often used in excess, can be controlled (reduced) to a necessary and sufficient amount, thus reducing costs. 【0026】 Figure 5 is an explanatory diagram illustrating another preferred arrangement of the adsorbent-filled containers 3 in the first embodiment. As shown in Figure 5, it is preferable that the multiple adsorbent-filled containers 3 are arranged via spacers 6. This makes it easy to adjust the filling rate of the first adsorbent 4 (and similarly, it makes it easy to adjust the filling rate of the second adsorbent 5). As mentioned above, the filling rate of the first adsorbent 4 can be adjusted by appropriately adjusting the amount of the first adsorbent 4 to be filled inside, but it is cumbersome to measure the amount to fill the containers each time the first adsorbent 4 is filled. However, by arranging multiple adsorbent-filled containers 3 via spacers 6 as shown in Figure 5, it is possible to change the filling rate while keeping the amount of the first adsorbent 4 and the second adsorbent 5 filled constant. In this embodiment, if the length of the spacers 6 can be changed as appropriate, the filling rate can be easily adjusted simply by changing the length of the spacers 6. Therefore, in this embodiment, it is preferable to prepare several types of spacers 6 with different lengths and select and use them as appropriate. In this embodiment, multiple spacers 6 of a certain length may be stacked and used to adjust the length of the spacers 6. The spacers 6 can be made of any metal, such as stainless steel. 【0027】 (Adjustment of the filling rate of the adsorbent) Here, the filling rate (volume filling rate) of the first adsorbent 4 and the second adsorbent 5 in the adsorbent-filled container 3 can be calculated using the following formula (1). 【0028】 【number】 In the above equation (1), γ... Volume packing ratio of the adsorbent (-) M...Weight of the adsorbent material (kg) V... Volume of the adsorbent-filled container (m³) 3 ) ρp…Density of the adsorbent (kg / m³) 3 ) That is the case. 【0029】 In this section, if the adsorbent is a carrier or similar material, it is assumed that its shape, mass, volume, and density are constant. However, some variation is acceptable. If the adsorbent is a powder, the density of the powder particles is used (e.g., 4.23 g / cm³ for sodium ferrite powder). 3 ). 【0030】 In equation (1), a certain weight M (kg) of adsorbent is placed in the adsorbent-filled container 3, in an amount that does not exceed the volume of the adsorbent-filled container 3. Since the volume of the adsorbent-filled container 3 is predetermined, this volume is given by V (m³). 3 Assuming this, the apparent mass density of the packed bed 41 (packed area) (see Figure 2A) can be determined (M / V (kg / m³) 3 )). The value obtained by dividing this value by the density of the carrier mentioned above is the volumetric filling rate γ of the adsorbent (carrier) in the adsorbent-filled container 3. 【0031】 Therefore, in this embodiment, the filling rate of the first adsorbent 4 and the second adsorbent 5 in the adsorbent-filled container 3 can be controlled by adjusting the weight M (filling amount) of the first adsorbent 4 and the second adsorbent 5, or by adjusting the volume of the adsorbent-filled container 3 using the spacer 6. 【0032】 As explained above, the packing rate of the first adsorbent 4 in a single unit can be arbitrarily adjusted within a range of over 0% and up to 100%. The packing rates of the first adsorbent 4 and the second adsorbent 5 can be, for example, around 0.48 to 0.6 (around 48% to 60%). This packing rate of 0.48 to 0.6 is defined as a preferred range based on the results of measuring the packing rate when an adsorbent with a sphere diameter of approximately 2 to 3 mm (equivalent volume sphere diameter) of the same volume as the adsorbent is packed into a column. 【0033】 (Effect of volume packing rate of adsorbent on adsorption rate) Furthermore, as an explanation of the premise, the effect of the volume packing rate (packing rate) of the adsorbent on the adsorption rate will be explained below. In the following explanation, Figure 6 is a conceptual diagram of the packed bed structure. Figure 7 is a conceptual diagram of the capture radius r. Figure 8 is a conceptual diagram of the total capture cross-sectional area (shaded area 8A in the figure). Figure 9 is a conceptual diagram showing the relationship between the inspected volume cross-section of the packed bed and the total cross-sectional area contributing to molecular capture (the shaded area 9A in the figure shows the cross-section contributing to capture). 【0034】 In the explanations in this section, the symbols have the following meanings: a…The characteristic length of the adsorbent. In the case of a cylinder, this is the radius of the cylinder. In the case of a shape other than a cylinder, it is given as the radius of a sphere of equivalent volume (same volume), and in the following discussion, it will be considered as a cylindrical adsorbent with radius a and the same volume. S... Cross-sectional area of ​​the packed bed (tank 2) F... Volume packing rate of the adsorbent in the packed bed (tank 2) r...Capture radius (see Figure 7) λ…Ratio of capture radius r to cylindrical adsorbent radius a: λ=r / a N(X)...Number concentration of molecules to be adsorbed at position X N in ...number concentration of molecules at the packed bed inlet (x coordinate zero) L...Length of the entire packed bed 【0035】 In the conceptual diagram of the packed bed shown in Figure 6, the x-coordinate is taken in the direction of gas flow (upward in the figure). The volume of the micro-inspection volume region enclosed between position (height in the figure) X and position X+dX (where a small amount dX is added) is expressed by equation (2-1). 【0036】 【number】 【0037】 Therefore, the volume of the adsorbent is given by equation (2-2), using the volume packing ratio F. 【0038】 【number】 【0039】 Therefore, the total length of all the adsorbents connected within the volume of the packed bed (inspection volume) is given by equation (2-3), which is obtained by dividing the volume in equation (2-2) by the cross-sectional area of ​​the cylinder, since the adsorbents are cylindrical. 【0040】 【number】 【0041】 If the distance from the center of the adsorbent that captures molecules, as shown in Figure 7, is defined as the capture radius r, then the total cross-sectional area contributing to molecule capture within the inspection volume region is given by equation (2-4), which is the sum of the lengths of all the adsorbents connected together (equation (2-3)) multiplied by twice the capture radius r, as shown in the conceptual diagram in Figure 8. 【0042】 【number】 【0043】 In Figure 9, the circular cross-section shows the cross-section of the packed bed, and the shaded region 9A shows the cross-sectional area that contributes to the trapping of molecules. The sum of the areas of the shaded region 9A is expressed by equation (2-4) above. Here, using the ratio λ of the capture radius r to the radius a, equation (2-4) can be transformed into equation (2-5). 【0044】 【number】 【0045】 The removal rate (adsorption rate) is obtained by dividing the difference (decrease) in the number concentration of molecules at position X and position X+dX by the concentration at the inlet position X. Since this can be considered to be defined by the ratio of the total cross-sectional area contributing to the capture to the cross-sectional area of ​​tank 2, the relationship in equation (2-6) holds. 【0046】 【number】 【0047】 Therefore, equation (2-7) is obtained from equations (2-5) and (2-6). If dX is an infinitesimal quantity, equation (2-7) is transformed into equation (2-8) (the numerator on the left side of equation (2-7) becomes dN(X)). 【0048】 【number】 【0049】 When considering the number concentration of molecules N(X) at an arbitrary position X, with the x-coordinate of the inlet of the packed bed being zero, the number concentration of molecules at the inlet is N in Therefore, the solution to equation (2-8) is given by equation (2-9). And, if the total length of the packed bed is L, then substituting L for X gives equation (2-10). 【0050】 【number】 【0051】 Set both sides of equation (2-10) to N in By dividing by and taking the logarithm of both sides, we obtain the relationship shown in equation (2-11). 【0052】 【number】 【0053】 The left side of equation (2-11) represents the logarithm of the remaining percentage of the adsorbed molecules, while the right side shows a term that is the product of the volumetric packing rate F and the packing length L. In other words, the product of the volumetric packing rate F and the packing length L is important for the removal (adsorption) of the molecules to be adsorbed, and these parameters are factors that determine the adsorption capacity of the adsorbent. As mentioned above, the packing rate of the adsorbent can be controlled by adjusting the weight M (filling amount) of the adsorbent or by adjusting the volume of the adsorbent-filled container 3 using the spacer 6. 【0054】 (Control of pressure loss) Next, we will explain the control of pressure loss. In the following explanation, Figure 10A is a conceptual diagram showing a model in which the adsorbent packing layer 241 (filling area) in the tank 102 is densely filled with adsorbent. Figure 10B is a conceptual diagram showing a model in which adsorbent is filled into an adsorbent-filling container 3 at a predetermined filling rate, and multiple containers are placed in the adsorbent packing layer 41 (filling area) in the tank 2. In these figures, the areas shown as diamond-shaped mesh patterns indicate the locations (cross-sections) where the adsorbent is filled. 【0055】 In the explanations in this section, the symbols have the following meanings: H...Height of the packed bed (packing area) (height of the area in tank 2 where the adsorbent is packed) h...Height of one adsorbent-filled container 3 (unit) ha... The depth of the adsorbent filling in one adsorbent-filled container 3 (unit) n...Number of adsorbent-filled containers 3 (units) stacked inside tank 2 k... The ratio of the height h of the adsorbent-filled container 3 (unit) to the filling depth ha of the adsorbent filled inside the adsorbent-filled container 3 (unit) (see equations (3-1) and (3-2) below). 【0056】 As shown in Figures 10A and 10B, the height h of the adsorbent-filled container 3 and the filling depth ha of the adsorbent filled in the adsorbent-filled container 3 are given as follows. Here, k in equation (3-2) is the ratio of the filling depth ha of the adsorbent to the height h of the adsorbent-filled container 3, and is a value between 0 and 1. 【0057】 【number】 【0058】 While the length of the packed bed 241 shown in Figure 10A is H, the length of the packed bed 41 shown in Figure 10B is given by equation (3-3). 【0059】 【number】 【0060】 As described above, since k is a value between 0 and 1, as is clear from the illustrations of FIGS. 10A and 10B, the length of the packed bed 41 in the tank 2 shown in FIG. 10B is shorter than the packed bed 241 in the tank 102 shown in FIG. 10A. Also, it is self-evident that the pressure loss in the portion where the adsorbent is not filled (non-packed portion) in FIG. 10B is smaller than that in the filled portion. As a result, the pressure loss from the raw gas introduction part 21 to the processed gas discharge part 22 of the tank 2 shown in FIG. 10B is lower than the pressure loss of the tank 102 shown in FIG. 10A. Also, the pressure loss in the non-packed portion in the tank 2 shown in FIG. 10B does not exceed the pressure loss of the packed bed. Therefore, the pressure loss of the gas fluid passing through the inside of the tank 2 shown in FIG. 10B, which is the structure provided by the present embodiment, does not exceed the pressure loss when the adsorbent is filled throughout the inside of the tank 102 as shown in FIG. 10A. This is due to the length of the packed bed. Since the sum of the filling depths ha of the adsorbent is n×ha, the control of the pressure loss can be performed with the ratio k of the height h of the adsorbent filling container 3 to the filling depth ha of the adsorbent filled in the adsorbent filling container 3, and the number n of the adsorbent filling containers 3. For example, reducing k can reduce the pressure loss, and increasing k can increase the pressure loss. 【0061】 (Specific Explanation of Pressure Loss Reduction) Next, a specific explanation of the reduction of the pressure loss will be given. In the explanation of this section, FIGS. 10A and 10B are referred to. In the explanation of this section, the symbols have the meanings shown in Table 1. Note that the equivalent volume sphere in Table 1 refers to a sphere having the same volume as the adsorbent. 【0062】 [Table 1] 【0063】 Let the pressure loss coefficient of the packed bed be f a and the pressure loss coefficient of the piping such as the wall surface of the tank 2 be f pAccording to Reference 1 (Asbestos, Kawaguchi, Flow Loss Model in a Packed Bed, Kanagawa Institute of Technology Research Report, B-18, 1994) and Reference 2 (Ito, Shiro, Fluid Engineering for Chemical Engineers, Kagaku Gijutsu Sha, 1983), f a It is expressed by equation (4-1). According to reference 3 (Masahiro Osakabe, Thermal Fluid Training for Energy Engineers, Kaibundo, 2004), when the Re number exceeds 1200, f p It is expressed by equation (4-2). According to the aforementioned reference 1, with respect to the coefficient A and the power B in equation (4-1), Re p For numbers in the range of 5 to 14, A=97 and B=0.886, Re p For numbers in the range of 30 to 96, A=55.1 and B=0.589. 【0064】 【number】 【0065】 The pressure loss Δp1 under the conditions shown for tank 102 in Figure 10A is given by equation (4-3), and the pressure loss Δp2 for tank 2 shown in Figure 10B is given by equation (4-4). In equation (4-4), the first term on the right-hand side corresponds to the pressure loss in the region filled with adsorbent, and the second term corresponds to the pressure loss in the unfilled region. Using the relationship for "thickness of the packed layer in the adsorbent-filled container" from the explanation of symbols in Table 1, equation (4-4) can be transformed into equation (4-5). 【0066】 【number】 【0067】 Next, we will explain the relationship between the magnitudes of Δp1 and Δp2. The difference between equations (4-3) and (4-5) is expressed by equation (4-6). 【0068】 【number】 【0069】 Equation (4-6) can be transformed into equation (4-7) using the "mean empty gas velocity in the packed bed" as explained in the symbols in Table 1. 【0070】 【number】 【0071】 Here, we compare the magnitudes of Δp1 and Δp2 in the following example. 〔conditions〕 Adsorbent cube with 3mm diameter (equivalent volume sphere diameter d = 3.7mm) The internal dimensions of tank 2, which is filled with adsorbent material (inner diameter of tank 2), are D=200mm x H=1200mm. The packing density of the adsorbent is β = 0.5 (50%) (therefore, the porosity of the packed bed is γ = 0.5). Number of adsorbent-filled containers 3: n = 10 Height of adsorbent-filled container 3: h = 120 mm The thickness of the packed layer inside the adsorbent-filled container 3 is ha = 60 mm. Under these conditions, the ratio of ha to h is k = 0.5 Average flow velocity of gaseous fluid (see explanation of symbols in Table 1) = 0.1 m / s 【0072】 In equation (4-7), the pressure loss coefficient f a and f b The relative magnitudes of Δp1 and Δp2 can be determined by the sign of the terms in equation (4-8), which are part of equation (4-7), based on the packed bed porosity γ and the inner diameter D of tank 2. 【0073】 【number】 【0074】 First, the Reynolds number Re in the packed area (packed bed) of the adsorbent in tank 2. pNext, we determine the Reynolds number Re in the unpacked region. According to the definitions shown in the explanation of the symbols in Table 1, it is necessary to use the representative diameter when determining these values. The representative diameter of the unpacked region (unpacked area) is D = 0.2 m, but using the definition shown in the explanation of the representative diameter of the packed bed (Table 1), the following value can be obtained using the diameter of the equivalent volume sphere d = 3.7 mm (Equation (4-9)). 【0075】 【number】 【0076】 Using this value, the Reynolds number Re of the packed region (packed layer) p The value of the Reynolds number Re of the unpacked region (unpacked area) is given by equation (4-10), and the value of the Reynolds number Re of the unpacked region (unpacked area) is given by equation (4-11). 【0077】 【number】 【0078】 The calculated Reynolds number Re p From Re, the pressure loss coefficient f in the adsorbent filling region. a This can be calculated using equation (4-1), but as explained at the beginning of this section, since the Reynolds number is 33, the coefficient A is 55.1 and the power B is 0.589, and the value is given by equation (4-12). 【0079】 【number】 【0080】 Furthermore, the pressure loss coefficient f in the unfilled region. p Using equation (4-1) and the Reynolds number value of 1300, the value is given by equation (4-13). 【0081】 【number】 【0082】 Therefore, when equation (4-8) is calculated, it yields a positive value as shown in equation (4-14), and the value of pressure loss Δp1 is larger than the value of pressure loss Δp2. 【0083】 【number】 【0084】 (An example of the filling structure and operation method of the adsorbent) The weight of the adsorbent increases as it adsorbs CO2. Figure 11 is a graph showing an example of the change in the amount of CO2 adsorbed by the adsorbent over time. In the figure, the horizontal axis represents the aeration time (minutes), and the vertical axis represents the amount of adsorption (mol-CO2 / g-adsorbent). This graph shows the results of an experiment in which an adsorbent was packed into a SUS pipe column. The SUS pipe column had an inner diameter × length = 10 mm × 100 mm, the adsorbent packing rate was 55.3%, the introduction velocity of the raw gas containing CO2 at the inlet was an average flow velocity of 0.1 m / s, and the gas temperature was 23°C. 【0085】 As shown in Figure 11, CO2 adsorption progressed rapidly immediately after the start of ventilation, and the amount of adsorbed material increased. After 20 minutes from the start of ventilation, the amount of adsorbed material was approximately 0.0033 mol-CO2 / g-adsorbent. After 60 minutes from the start of ventilation, the amount of adsorbed material was approximately 0.0036 mol-CO2 / g-adsorbent, reaching a near-saturation state. At the aforementioned point after 20 minutes from the start of ventilation, the amount of adsorbed material was approximately 90-95% of the near-saturation state. 【0086】 Table 2 shows an example of the results of measuring the weight increase rate at the point when adsorption rupture occurred by passing a raw gas containing CO2 through two different types of adsorbents, A and B. As shown in Table 2, adsorbent A had a minimum weight increase rate of 14.9%, a maximum weight increase rate of 15.8%, an average weight increase rate of 15.375%, and a deviation of 0.377492. Adsorbent B had a minimum weight increase rate of 7.2%, a maximum weight increase rate of 8.3%, an average weight increase rate of 7.825%, and a deviation of 0.485627. The weight increase rates at the time of adsorption rupture for adsorbents A and B shown in Table 2 were approximately 7% to 16%, indicating that the rupture state can be confirmed by the weight change. 【0087】 [Table 2] 【0088】 Therefore, for example, by determining the time interval for periodic inspections and measuring and calculating the rate of change from the initial weight of the adsorbent in each unit during inspections or overhauls, it is possible to identify which units require adsorbent replacement. Then, only the adsorbent in the units that need replacement should be replaced. Alternatively, the adsorbent should be replaced unit by unit (each adsorbent-filled container 3). Furthermore, by knowing in advance the adsorption capacity of the adsorbent material as shown in Figure 11, and creating a database of the relationship between ventilation time and adsorption amount, it becomes possible to predict the deterioration state by, for example, measuring the CO2 concentration at the treated gas discharge section 22 and referring to the database. 【0089】 [Second Embodiment] Figure 12 is a schematic diagram illustrating the configuration of the CO2 separation and recovery device 1 according to the second embodiment. Figure 12 shows an example of the arrangement of the adsorbent-filled container 3 inside the tank 2 of the CO2 separation and recovery device 1 according to the second embodiment. The CO2 separation and recovery device 1 according to the second embodiment is a modified version of the CO2 separation and recovery device 1 according to the first embodiment. The adsorbent-filled container 3 in the second embodiment also has a mesh-like structure 31 with an opening smaller than the size of the first adsorbent 4 at least at the bottom 32, similar to one embodiment described in the first embodiment. It is preferable that the mesh-like structure 31 also be present on the side walls 33 of the adsorbent-filled container 3. This embodiment also has a plurality of such adsorbent-filled containers 3. 【0090】 Furthermore, each of the multiple adsorbent-filled containers 3 is arranged sequentially such that its bottom 32 is perpendicular to the direction of travel of the introduced raw gas containing CO2. However, as shown in Figure 12, although the CO2 separation and recovery device 1 according to the second embodiment has the adsorbent-filled containers 3 stacked vertically, each stage of the adsorbent-filled container 3 is provided with a gas flow path GP to facilitate the flow of the raw gas. This gas flow path GP is provided so as to maximize the distance the raw gas travels (to allow it to bypass). The gas flow path GP can be suitably formed by the following configuration. 【0091】 For example, in the second embodiment, as shown in Figure 12, an adsorbent-filled container 3 having a side wall portion 33 on only one side is used. The adsorbent-filled container 3 is fixed with a spacer 6 while the end portion 33a without the side wall portion 33 is in contact with one inner wall 23a inside the tank 2. In this case, the fixing of the adsorbent-filled container 3 with the spacer 6 is done alternately on one inner wall 23a side and the other inner wall 23b side inside the tank 2 in the same manner as above. Furthermore, as shown in Figure 13, the gas flow path GP may be provided with an inner pipe 34 that penetrates the bottom 32 at any point on the bottom 32 of the adsorbent-filled container 3. Figure 13 is a schematic diagram showing one example of the configuration of the adsorbent-filled container 3 in the second embodiment. 【0092】 As shown in Figures 12 and 13, the travel distance of the raw gas can be increased, as described above. In the embodiments shown in Figures 12 and 13, as the raw gas moves through the gas flow path GP, the CO2 contained in the raw gas is adsorbed onto the first adsorbent 4 filled in the adsorbent-filled container 3. In this embodiment, for example, when the concentration of CO2 in the raw gas is low, CO2 can be removed effectively while further reducing pressure loss. Furthermore, in the embodiment shown in Figure 12, the filling rate can be easily adjusted by changing the height of the spacer 6 to adjust the spacing between the adsorbent-filled containers 3. Furthermore, in the embodiment shown in Figure 13, spacers 6 can be placed between the adsorbent-filled containers 3 to adjust the distance between them, allowing for easy adjustment of the filling rate (this embodiment is not shown in Figure 13). 【0093】 In both embodiments shown in Figures 12 and 13, it goes without saying that, as in the first embodiment, the second adsorbent 5 can be used instead of the first adsorbent 4, or the filling rate of the first adsorbent 4 can be increased closer to the raw gas introduction section 21. 【0094】 [Third Embodiment] Figure 14 is a schematic diagram illustrating the configuration of the CO2 separation and recovery device 1 according to the third embodiment. Figure 14 shows an example of the configuration of the tank 2 of the CO2 separation and recovery device 1 according to the third embodiment. As shown in Figure 14, the CO2 separation and recovery device 1 according to the third embodiment includes a tank 2 filled with a first adsorbent 4 that adsorbs CO2. In the third embodiment, the tank 2 is configured such that a cylindrical body 23 is divided into multiple parts, and these multiple bodies 23 are arranged (connected) in sequence. Furthermore, the tank 2 is configured such that a mesh-like structure 31 with an opening smaller than the size of the first adsorbent 4 is provided at the bottom 231 of each of the multiple cylindrical bodies 23. In other words, in the third embodiment, as one way of partitioning the inside of the tank 2 in multiple stages with the mesh-like structure 31, the mesh-like structure 31 is provided at the bottom 231 of each of the multiple cylindrical bodies 23. 【0095】 In this embodiment, the tank 2 is divided into multiple sections, and the first adsorbent 4 is filled into each section of the divided tank 2. The tank bottom 24, the tank lid 25, and the divided cylindrical body 23 positioned between them can be detachably fixed with bolts 26 and nuts 27, respectively, and when fixed, a sealed internal space can be obtained. In this embodiment, when replacing the first adsorbent 4, the bolts 26 and nuts 27 can be removed, and the first adsorbent 4 can be replaced as a single unit consisting of the body 23 and the bottom 231. 【0096】 In the third embodiment of the CO2 separation and recovery apparatus 1, the filling rate of the first adsorbent 4 in the multi-stage partitioned tank 2 can be arbitrarily adjusted, similar to the first embodiment (the amount of adsorbent can be controlled). Furthermore, in this embodiment, pressure loss can be actively controlled. Moreover, in this embodiment, since the filling rate of the first adsorbent 4 in the multi-stage partitioned tank 2 can be arbitrarily adjusted, it is also possible to control the amount of the first adsorbent 4 to a necessary and sufficient amount. 【0097】 It goes without saying that, in this third embodiment as well, the second adsorbent 5 can be used instead of the first adsorbent 4, or the filling rate of the first adsorbent 4 can be increased closer to the raw gas introduction section 21. 【0098】 (Explanation of the combustion process; explanation of the gas composition of the combustion gases) This section will explain the combustion process. Specifically, it will explain the composition of the combustion gases. Figure 15 is an explanatory diagram illustrating an example of the combustion process. For example, when burning city gas 13A in a gas engine or boiler, equation (5-1) in Figure 15 is the combustion reaction equation. As shown in equation (5-1), 1 mole of methane (CH4) reacts with 2 moles of oxygen (O2) to produce 1 mole of CO2 and 2 moles of water (H2O). The source of O2 is air, and the gas composition of the air is approximately assumed to be 79% nitrogen (N2) and 21% O2. In this case, the mass balance of combustion is given by the fuel gas flow rate Q(m 3Assuming this ratio is / h, it is shown by equations (5-2) to (5-5) in Figure 15. Theoretically, approximately 9.5 times the amount of air as O2 is required, and approximately 7.5 times the amount of N2 that does not contribute to combustion is accompanied by it (equation (5-3) in Figure 15). In actual combustion reactions, since the combustion of 1 mole of CH4 requires the supply of more than 2 moles of O2, it is necessary to supply more than 1 times the amount of air required under ideal conditions containing 2 moles of O2. If this air ratio is N (a value greater than 1), and the flow rate of CH4 is represented as Q, then the gas mass balance of the gas components in the combustion gas composition is shown by equations (5-2) to (5-5) in Figure 15. Table 3 shows the composition of the combustion gas. 【0099】 [Table 3] 【0100】 The combustion gas is composed of N2, CO2, H2O, and O2, as shown in equation (5-1) and the reaction in Figure 15 (Table 3). Since the air ratio N is greater than 1, the CO2 concentration is approximately 12% or less when H2O is absent, and approximately 9.5% or less when H2O is present. For example, in the case of a typical air ratio of N=1.4, the CO2 concentration is approximately 7% when H2O is present, and approximately 8% when water is removed. 【0101】 The CO2 separation and recovery apparatus 1 according to the first to third embodiments described above can recover CO2 contained in the combustion gas (raw gas) at the aforementioned concentrations (approximately 7% and approximately 8%) by adsorption with the first adsorbent 4. The first adsorbent 4, which has adsorbed CO2, is removed from the CO2 separation and recovery device 1 and then subjected to a recovery device for recovering CO2 gas, where it undergoes at least one of the following treatments: reduced pressure and heating. As a result, CO2 is released from the first adsorbent 4 and recovered, and is then reformed into CH4 or other substances as needed, or stored. 【0102】 As described above, the CO2 separation and recovery apparatus 1 according to the first to third embodiments can control the amount of adsorbent (first adsorbent 4) used when adsorbing CO2 and control the pressure loss. Furthermore, the CO2 separation and recovery apparatus 1 can replace only a portion of the adsorbent (first adsorbent 4 and second adsorbent) with new ones as needed. 【0103】 Although the CO2 separation and recovery apparatus 1 according to the present invention has been described in detail above with reference to embodiments, the present invention is not limited to the embodiments described above and includes various modifications. For example, the embodiments described above are described in detail for the purpose of explaining the present invention in an easy-to-understand manner and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. [Explanation of Symbols] 【0104】 1 CO2 separation and recovery device 2 tanks 21 Raw gas inlet section 22. Processed gas discharge section 3 Container filled with adsorbent 31 Mesh-like structure 32 Bottom 4 First adsorbent 5 Second adsorbent 6 Spacers

Claims

[Claim 1] CO ２ CO2 separation and recovery ２ It is a separation and recovery device, The aforementioned CO ２ The tank is filled with a first adsorbent that adsorbs, The tank is divided into multiple sections by a mesh-like structure with an opening smaller than the size of the first adsorbent. Each of the multi-stages is filled with the first adsorbent. CO, characterized by ２ Separation and recovery device. [Claim 2] The tank has a plurality of adsorbent-filled containers, each having the mesh-like structure at least at the bottom. All of the above multiple adsorbent-filled containers are equipped with the CO2 that has been introduced into them. ２ The tanks are partitioned into multiple stages by sequentially arranging them so that their bottoms are perpendicular to the direction of travel of the raw gas containing the raw gas. CO according to Feature 1 ２ Separation and recovery device. [Claim 3] In at least one of the multi-stage partitioned sections, the CO2 is replaced with the first adsorbent. ２ CO1, characterized in that it is filled with a second adsorbent that can adsorb gas components with smaller molecular sizes than the first adsorbent. ２ Separation and recovery device. [Claim 4] The CO separation and recovery device according to claim 1, wherein each of the multi-stage partitions is filled with the first adsorbent at a different filling rate. ２ separation and recovery device. [Claim 5] The aforementioned CO ２ The raw gas inlet section into which the raw gas containing the CO2 is introduced and the CO2 ２ Adsorption occurs and the CO ２ It has a treatment gas discharge section from which the treated gas from which the waste has been removed is discharged. The CO2 ２ Separation and recovery device. [Claim 6] CO2 as described in claim 2, characterized in that the plurality of adsorbent-filled containers are arranged via spacers. ２ Separation and recovery device.

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