Carbon dioxide concentration device

Abstract

To provide a carbon dioxide concentration device capable of efficiently recovering highly concentrated carbon dioxide.SOLUTION: A CO2 concentration device 1 is provided with a first gas passage 3 and a second gas passage 4 to flow a CO2-containing gas in th same direction respectively and a plurality of honeycomb structures 10 with CO2 adsorbents disposed in series at the inside of each gas passage. The first gas passage 3 is heated. In the uppermost stream sides of the first gas passage 3 and the second gas passage 4, a first mechanism 7 to transfer the honeycomb structure 10 at the uppermost stream of the second gas passage 4 to the uppermost stream of the first gas passage 3 and push out the honeycomb structure 10 transferred to the uppermost stream of the first gas passage 3 to the downstream side of the first gas passage 3 is disposed. In the lowermost stream side of the first gas passage 3 and the second gas passage 4, a second mechanism 8 to transfer the honeycomb structure 10 at the lowermost stream of the first gas passage 3 to the lowermost stream of the second gas passage 4 and push out the honeycomb structure 10 transferred to the lowermost stream of the second gas passage 4 to the upstream side of the second gas passage 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a carbon dioxide concentrating device that separates and concentrates carbon dioxide contained in a carbon dioxide-containing gas. [Background technology]

[0002] Conventionally, such a technical field is, for example, described in Patent Document 1. In the carbon dioxide concentrating device described in Patent Document 1, a honeycomb rotor carrying a carbon dioxide adsorbent rotates, and high-temperature gas and low-temperature gas containing carbon dioxide are alternately supplied by the rotation of the honeycomb rotor, and the carbon dioxide adsorbed at the point where the high-temperature gas hits is desorbed, thereby separating the gas into a high-concentration carbon dioxide gas and a carbon dioxide-removed gas, and the high-concentration carbon dioxide is recovered. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-062862 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned carbon dioxide concentrating device, due to factors such as the inability to heat the entire adsorbent uniformly, carbon dioxide is desorbed before it is sufficiently adsorbed by the honeycomb rotor, and therefore carbon dioxide cannot be recovered efficiently.

[0005] The present invention has been made to solve such technical problems, and has an object to provide a carbon dioxide concentrating device that can efficiently recover high-concentration carbon dioxide. [Means for solving the problem]

[0006] The carbon dioxide concentrating apparatus according to the present invention is a carbon dioxide concentrating apparatus that separates and concentrates carbon dioxide contained in a carbon dioxide-containing gas, and includes a first gas flow path and a second gas flow path that branch off from a supply pipe for the carbon dioxide-containing gas and allow the carbon dioxide-containing gas to flow in the same direction, and a plurality of honeycomb structures carrying a carbon dioxide adsorbent that are arranged in series inside the first gas flow path and the second gas flow path, respectively, and the first gas flow path is arranged so that a temperature of the plurality of honeycomb structures arranged therein is higher than a temperature of the plurality of honeycomb structures arranged inside the second gas flow path. The gas passage is heated, and a first mechanism is provided at the most upstream side of the first gas flow path and the second gas flow path, which transfers a honeycomb structure at the most upstream side of the second gas flow path to the most upstream side of the first gas flow path and pushes the honeycomb structure transferred to the most upstream side of the first gas flow path to the downstream side of the first gas flow path, and a second mechanism is provided at the most downstream side of the first gas flow path and the second gas flow path, which transfers a honeycomb structure at the most downstream side of the first gas flow path to the most downstream side of the second gas flow path and pushes the honeycomb structure transferred to the most downstream side of the second gas flow path to the upstream side of the second gas flow path.

[0007] In the carbon dioxide concentrating device according to the present invention, a plurality of honeycomb structures carrying a carbon dioxide adsorbent are arranged in series inside the first gas flow path and the second gas flow path, respectively, and the first and second mechanisms circulate the gas through the first and second gas flow paths. The first gas flow path is heated so that the temperature of the plurality of honeycomb structures arranged therein is higher than the temperature of the plurality of honeycomb structures arranged in the second gas flow path, so that the second gas flow path can be a carbon dioxide adsorption zone and the first gas flow path can be a carbon dioxide desorption zone. In this way, the honeycomb structures arranged in the first and second gas flow paths are circulated to repeatedly adsorb and desorb carbon dioxide, thereby making it possible to efficiently recover high-concentration carbon dioxide. Effect of the Invention

[0008] According to the present invention, high-concentration carbon dioxide can be efficiently recovered. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a CO2 concentrating device according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing a honeycomb structure. [Diagram 3] FIG. 1 is a graph showing the relationship between the temperature of a solid adsorbent material and the amount of CO2 adsorption. [Figure 4] FIG. 2 is a schematic diagram illustrating an example in which the CO2 concentrating device according to the embodiment is applied to an existing facility. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a carbon dioxide (CO2) concentrating apparatus according to the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and the duplicated description will be omitted. In addition, "upstream" and "downstream" in the description are based on the flow direction of the CO2-containing gas supplied from the supply pipe.

[0011] FIG. 1 is a schematic diagram showing a CO2 concentrating apparatus according to an embodiment, and in FIG. 1, the gray portion is a CO2 adsorption concentration distribution. The CO2 concentrating apparatus 1 according to this embodiment is an apparatus for separating and concentrating CO2 contained in a CO2-containing gas, and includes a frame 2 formed of a plurality of metal frames and metal plates, and two pipes supported by the frame 2 and arranged in parallel. One of the two pipes forms a first gas flow path 3 for passing the CO2-containing gas, and the other forms a second gas flow path 4 for passing the CO2-containing gas.

[0012] As shown in Fig. 1, the first gas flow path 3 and the second gas flow path 4 branch off from a CO2-containing gas supply pipe 9, and the CO2-containing gas supplied from the supply pipe 9 flows in the same direction. Here, the flow direction of the CO2-containing gas is the same as the longitudinal direction of the frame 2. The first gas flow path 3 is provided at both ends in the longitudinal direction with bellows portions 5L and 5R that can expand and contract in the longitudinal direction. Similarly, the second gas flow path 4 is provided at both ends in the longitudinal direction with bellows portions 6L and 6R that can expand and contract in the longitudinal direction of the second gas flow path 4.

[0013] A plurality of honeycomb structures 10 are disposed inside the first gas flow passage 3 and the second gas flow passage 4. As shown in Fig. 2, the honeycomb structure 10 has a cylindrical main body 11, a CO2 adsorbent 12 fitted inside the main body 11, and a plurality of fins 13 protruding in the circumferential direction from the outer wall of the main body 11. In addition, a pair of guide portions 14 having a U-shaped cross section are protruding from the outer wall of the main body 11 on the left and right.

[0014] The CO2 adsorbent 12 is a honeycomb structure that supports a CO2 adsorbent and has a plurality of through holes that serve as passages for the CO2-containing gas. The CO2 adsorbent may be any material that can adsorb and desorb CO2, and examples of such materials include solid adsorbents such as zeolite, activated carbon, and silica gel.

[0015] The guide portion 14 is disposed so as to be parallel to the axial direction of the cylindrical main body 11. The guide portion 14 is structured to fit with a rail (not shown) provided on the inner wall of the first gas flow passage 3 or the second gas flow passage 4. When the guide portion 14 is disposed inside the first gas flow passage 3 or the second gas flow passage 4, the guide portion 14 fits with the rail of the first gas flow passage 3 or the second gas flow passage 4, so that the honeycomb structure 10 can move linearly along the rail while being restricted by the rail.

[0016] A plurality of honeycomb structures 10 having such a structure are arranged in series along the longitudinal direction of the first gas flow passage 3 or the second gas flow passage 4. As shown in Fig. 1, in this embodiment, 20 honeycomb structures 10 are arranged in series inside the first gas flow passage 3 and the second gas flow passage 4. The 20 honeycomb structures 10 arranged in the first gas flow passage 3 are shifted by one honeycomb structure 10 from the 20 honeycomb structures 10 arranged in the second gas flow passage 4.

[0017] Specifically, for example, when the honeycomb structures 10 are arranged in the order of 1st, 2nd, ..., 20th from upstream to downstream, in the longitudinal direction of the first gas flow passage 3 and the second gas flow passage 4, the first honeycomb structure 10 on the first gas flow passage 3 side is in the same position as the second honeycomb structure 10 on the second gas flow passage 4 side, and the 19th honeycomb structure 10 on the first gas flow passage 3 side is in the same position as the 20th honeycomb structure 10 on the second gas flow passage 4 side. Therefore, in the first gas flow passage 3, there is no honeycomb structure 10 that is arranged in the same position as the first honeycomb structure 10 on the second gas flow passage 4 side. Similarly, in the second gas flow passage 4, there is no honeycomb structure 10 that is arranged in the same position as the 20th honeycomb structure 10 on the first gas flow passage 3 side.

[0018] The difference in flow path length caused by such misalignment is adjusted by the expansion and contraction of the above-mentioned bellows portions 5L, 5R, 6L, and 6R. For example, the bellows portion 5R on the first gas flow path 3 side is expanded so as to have the same length as the entire length of the first honeycomb structure 10 and the bellows portion 6R on the second gas flow path 4 side, and the bellows portion 6L on the second gas flow path 4 side is expanded so as to have the same length as the entire length of the twentieth honeycomb structure 10 and the bellows portion 5L on the first gas flow path 3 side.

[0019] Further, a first mechanism 7 is provided on the most upstream side of the first gas flow passage 3 and the second gas flow passage 4, which transfers the honeycomb structure 10 at the most upstream of the second gas flow passage 4 to the most upstream of the first gas flow passage 3 and pushes out the honeycomb structure 10 transferred to the most upstream of the first gas flow passage 3 to the downstream side of the first gas flow passage 3. The first mechanism 7 is configured to have a rotation drive unit and an extrusion drive unit.

[0020] The rotary drive unit includes, for example, a rotating disk 71 to which the bellows portion 5R on the first gas flow path 3 side and the bellows portion 6R on the second gas flow path 4 side are respectively fixed, and a motor (not shown) for rotating the rotating disk 71 about its center.

[0021] The extrusion drive unit has a push rod 72 that can swing about its geometric center as an axis, and a cylinder (not shown) for swinging the push rod 72. One end of the push rod 72 is fixed to the most upstream end of the first gas flow passage 3, and the other end is fixed to the most upstream end of the second gas flow passage 4. In addition, the push rod 72 is formed so as to be rotatable by a rotating disk 71 together with the bellows portion 5R in an expanded state, the bellows portion 6R in a contracted state, and the honeycomb structure 10 at the most upstream of the second gas flow passage 4.

[0022] Furthermore, the push rod 72 can push out the first honeycomb structure 10 on the first gas flow passage 3 side to the downstream side of the first gas flow passage 3 by driving the cylinder. Note that in the push-out driving unit, an actuator or the like may be used instead of the cylinder.

[0023] The first mechanism 7 having such a structure is controlled by a control unit (not shown) and operates according to a command from the control unit. For example, when the motor of the rotation drive unit receives a drive command from the control unit and rotates, the rotating disk 71 rotates 180° (see the dashed arrow in FIG. 1). Accordingly, the bellows portion 6R fixed to the rotating disk 71, the most upstream honeycomb structure 10 on the second gas passage 4 side (i.e., the first honeycomb structure 10), the bellows portion 5R, and the extrusion rod 72 also rotate. As a result, the bellows portion 6R fixed to the rotating disk 71 and the most upstream honeycomb structure 10 on the second gas passage 4 side are transferred to the most upstream of the first gas passage 3, and the bellows portion 5R fixed to the rotating disk 71 is transferred to the most upstream of the second gas passage 4.

[0024] When the rotation drive unit stops, the control unit transmits a drive command to the cylinder of the extrusion drive unit, and the cylinder drives the extrusion rod 72 according to the command. The extrusion rod 72 swings about its center of shape as an axis, and is transferred to the most upstream position of the first gas flow passage 3, and extrudes the honeycomb structure 10 to the downstream side of the first gas flow passage 3. At this time, the bellows portion 6R in the contracted state expands, and the bellows portion 5R in the expanded state contracts.

[0025] In addition, a second mechanism 8 is provided on the most downstream side of the first gas flow passage 3 and the second gas flow passage 4, which transfers the honeycomb structure 10 at the most downstream of the first gas flow passage 3 to the most downstream of the second gas flow passage 4 and pushes the honeycomb structure 10 transferred to the most downstream of the second gas flow passage 4 to the upstream side of the second gas flow passage 4.

[0026] The second mechanism 8 has a structure similar to that of the first mechanism 7 described above, and therefore will not be described again. However, the second mechanism 8 differs from the first mechanism 7 in that it transports the honeycomb structure 10 at the most downstream position of the first gas flow path 3 (i.e., the 20th honeycomb structure 10) to the most downstream position of the second gas flow path 4 and pushes it out to the upstream side of the second gas flow path 4.

[0027] The first mechanism 7 and the second mechanism 8 are controlled by the control unit to operate simultaneously. That is, the operation of transferring the most upstream honeycomb structure 10 of the second gas flow passage 4 to the most upstream of the first gas flow passage 3 by the first mechanism 7 and the operation of transferring the most downstream honeycomb structure 10 of the first gas flow passage 3 to the most downstream of the second gas flow passage 4 by the second mechanism 8 are performed simultaneously, and the operation of pushing out the honeycomb structure 10 to the downstream side of the first gas flow passage 3 by the first mechanism 7 and the operation of pushing out the honeycomb structure 10 to the upstream side of the second gas flow passage 4 by the second mechanism 8 are performed simultaneously.

[0028] The first gas flow passage 3 is heated so that the temperature of the plurality of honeycomb structures 10 arranged therein is higher than the temperature of the plurality of honeycomb structures 10 arranged in the second gas flow passage 4. On the other hand, the second gas flow passage 4 is not heated. The first gas flow passage 3 may be heated by utilizing high-temperature exhaust gas discharged from an existing facility, or by laying a pipe along the first gas flow passage 3 and circulating heated water through the pipe.

[0029] Fig. 3 is a diagram showing the relationship between the temperature of a solid adsorbent and the amount of CO2 adsorbed. As shown in Fig. 3, the solid adsorbent has a characteristic that the lower the temperature, the greater the amount of CO2 adsorbed, and the higher the temperature, the less the amount of CO2 adsorbed (in other words, CO2 desorbs). Therefore, in this embodiment, a solid adsorbent having such a characteristic is used for the CO2 adsorbent 12, and a high-temperature zone and a low-temperature zone (or a normal temperature zone) are provided, and the CO2 adsorbent 12 is circulated between the high-temperature zone and the low-temperature zone, thereby repeatedly adsorbing and desorbing CO2, and concentrating the CO2 gas contained in the low-CO2 concentration exhaust gas (i.e., CO2-containing gas).

[0030] In order to concentrate the CO2 gas, the first gas flow passage 3 is heated as described above, but the second gas flow passage 4 is not heated. That is, in this embodiment, the second gas flow passage 4 forms a low temperature zone, and the first gas flow passage 3 forms a high temperature zone. In other words, in the second gas flow passage 4, a CO2 adsorption zone is formed by the CO2 adsorbents 12 of the honeycomb structures 10 arranged in the second gas flow passage 4. On the other hand, in the first gas flow passage 3, a CO2 desorption zone is formed by the CO2 adsorbents 12 of the honeycomb structures 10 arranged in the first gas flow passage 3.

[0031] Therefore, in the second gas flow passage 4, the CO2 adsorbent 12 of each honeycomb structure 10 moves from downstream to upstream and adsorbs CO2 in the CO2-containing gas flowing through the second gas flow passage 4. Therefore, as shown in the CO2 adsorption concentration distribution in gray in FIG. 1, the CO2 adsorption concentration gradually increases from downstream to upstream. The honeycomb structure 10 that reaches the most upstream of the second gas flow passage 4 has the highest CO2 adsorption concentration. The honeycomb structure 10 that reaches the most upstream is transported to the most upstream of the first gas flow passage 3 (desorption zone) by the above-mentioned first mechanism 7, and is further pushed out to the downstream side of the first gas flow passage 3.

[0032] On the other hand, in the first gas flow passage 3, the temperature of the CO2 adsorbent 12 increases due to heating, so that as the CO2 adsorbent 12 of each honeycomb structure 10 moves from the upstream side to the downstream side, the CO2 adsorbed in the CO2 adsorbent 12 is pushed out and desorbed from the CO2 adsorbent 12. Therefore, in the first gas flow passage 3, the concentration of CO2 in the first gas flow passage 3 gradually increases from the upstream side to the downstream side. Then, the honeycomb structure 10 that reaches the most downstream of the first gas flow passage 3 is in a state where all the CO2 has been desorbed, and is transported to the most downstream of the second gas flow passage 4 (adsorption zone) by the above-mentioned second mechanism 8, and is further pushed out to the upstream side of the second gas flow passage 4.

[0033] 1, a first throttle 21 is provided between the supply pipe 9 and the bellows portion 5R on the first gas flow path 3 side to adjust the flow rate of the CO2-containing gas supplied from the supply pipe 9 to the first gas flow path 3. In addition, a second throttle 22 is provided downstream of the bellows portion 5L on the first gas flow path 3 side to adjust the flow rate of the CO2-rich exhaust gas discharged from the first gas flow path 3. These throttles are each controlled by the above-mentioned control unit, and the degree of throttling is adjusted based on a command from the control unit.

[0034] In this way, by adjusting the degree of throttling of the first orifice 21 and / or the degree of throttling of the second orifice 22 via the control unit, the flow rate of the CO2-containing gas to the first gas flow path 3 and / or the flow rate of the CO2-rich exhaust gas from the first gas flow path 3 can be adjusted, thereby realizing concentration control of the CO2-rich exhaust gas. Although not shown, for example, a concentration sensor is installed between the bellows portion 5L and the second orifice 22, and the control unit adjusts the degree of throttling of the first orifice 21 and the second orifice 22 based on the result of the CO2-rich exhaust gas measured by the concentration sensor.

[0035] In the CO2 concentrator 1 of this embodiment, as shown by the white arrow in FIG. 1, the CO2-containing gas (e.g., low-CO2 concentration exhaust gas) supplied from the supply pipe 9 is branched and flows into the first gas flow passage 3 and the second gas flow passage 4, respectively. When the CO2-containing gas flowing into the second gas flow passage 4 passes through each honeycomb structure 10 arranged in the second gas flow passage 4 in order, the CO2 contained therein is adsorbed by the CO2 adsorbent 12 and removed (also called separated). Finally, the exhaust gas from which the CO2 has been removed (CO2-removed exhaust gas) is discharged to the outside. And, since the second gas flow passage 4 is not heated, the CO2-removed exhaust gas is discharged from the second gas flow passage 4 while being kept at room temperature.

[0036] Meanwhile, since the first gas flow passage 3 is heated, each honeycomb structure 10 arranged in the first gas flow passage 3 is heated to a predetermined temperature (for example, 120°C) or higher. Therefore, the CO2-containing gas flowing through the first gas flow passage 3 gradually increases in concentration while pushing out the CO2 desorbed from the CO2 adsorbent 12 in the high temperature environment, and is discharged from the first gas flow passage 3. Therefore, the gas discharged from the first gas flow passage 3 becomes a CO2-rich exhaust gas.

[0037] In this embodiment, as described above, the first mechanism 7 and the second mechanism 8 are used to circulate the honeycomb structures 10 arranged in the first gas flow path 3 and the second gas flow path 4 (see the solid arrows in FIG. 1), thereby repeatedly adsorbing and desorbing CO2 by the CO2 adsorbent 12 of the honeycomb structure 10. As a result, high-concentration CO2 can be efficiently collected. In addition, since CO2 is preferentially desorbed from the honeycomb structure 10 to which high-concentration CO2 is adsorbed, high-concentration CO2 can be collected more efficiently.

[0038] In this embodiment, the second gas flow path 4 may be cooled by utilizing the room temperature CO2-removed exhaust gas discharged from the second gas flow path 4. For example, a return pipe is laid along the second gas flow path 4 so as to return the CO2-removed exhaust gas discharged from the second gas flow path 4 to the second gas flow path 4 side, thereby cooling the second gas flow path 4.

[0039] The CO2 concentrating device 1 of this embodiment can be applied to various existing facilities that discharge CO2-containing gas. An example will be described below with reference to Fig. 4. Here, an example will be given of concentrating CO2-containing gas discharged from an aluminum melting furnace, which is an existing facility 100.

[0040] In an aluminum melting furnace, the CO2-containing gas discharged from the furnace has a CO2 concentration of about 10% or less, but the gas temperature exceeds 600°C. The CO2-containing gas contains a lot of soot, so it is necessary to remove the soot using a filter or other device. Since filters for removing soot are not suitable for high temperatures, the exhaust gas is mixed with a large amount of outside air to lower the temperature (for example, to below 50°C) and then the soot is removed. As a result, the CO2-containing gas discharged from the aluminum melting furnace becomes low-concentration CO2 exhaust gas at room temperature and is released into the atmosphere.

[0041] Therefore, the CO2 concentrating device 1 of this embodiment is used to concentrate and recover the CO2 contained in the CO2-containing gas (that is, low-CO2 concentration exhaust gas) discharged from an aluminum melting furnace.

[0042] Specifically, as shown in Figure 4, first, aluminum metal is melted in an aluminum melting furnace using city gas. The CO2-containing gas discharged from the aluminum melting furnace has a temperature of about 600°C and contains CO2 at a concentration of 10% or less. The CO2-containing gas is cooled to about 300°C in a heat exchanger, and is further mixed with outside air to become gas at a temperature of about 30°C and with a concentration of 1% or less.

[0043] After mixing with outside air, the CO2-containing gas passes through a dust collector consisting of a filter to remove soot contained in the gas, resulting in the low-CO2 concentration exhaust gas mentioned above.

[0044] Next, the CO2-containing gas is supplied to the CO2 concentrator 1 of this embodiment, and is separated into a CO2-rich exhaust gas and a CO2-removed exhaust gas as described above. The CO2-rich exhaust gas is collected, and the CO2-removed exhaust gas is discharged to the outside. Note that the chain line arrows in FIG. 4 indicate the circulation of the honeycomb structure 10 arranged in the first gas flow passage 3 and the second gas flow passage 4.

[0045] 4, in the CO2 concentrator 1, it is preferable to use high-temperature exhaust gas (about 300°C) before mixing with outside air to heat the first gas flow path 3. By using the heat of the high-temperature exhaust gas generated in the existing equipment 100 in this way for CO2 desorption from the CO2 adsorbent 12, it is not necessary to install a special heat source solely for heating the first gas flow path 3.

[0046] As shown in the example of Fig. 4, simply adding the CO2 concentrator 1 of this embodiment to an aluminum melting furnace makes it possible to concentrate and efficiently recover CO2 contained in the CO2-containing gas discharged from the aluminum melting furnace. Moreover, since the modification of the aluminum melting furnace required for application of the CO2 concentrator 1 can be minimized, the effect of enhancing the versatility of the CO2 concentrator 1 can be expected.

[0047] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as described in the claims. [Explanation of symbols]

[0048] 1: CO2 concentrator, 2: frame, 3: first gas flow path, 4: second gas flow path, 5L, 5R: bellows, 6L, 6R: bellows, 7: first mechanism, 8: second mechanism, 9: supply pipe, 10: honeycomb structure, 11: main body, 12: CO2 adsorbent, 13: fin, 14: guide, 21: first aperture, 22: second aperture, 71: rotating disk, 72: extrusion rod, 100: existing equipment

Claims

[Claim 1] A carbon dioxide concentrating device that separates and concentrates carbon dioxide contained in a carbon dioxide-containing gas, a first gas flow path and a second gas flow path branching from the carbon dioxide-containing gas supply pipe and allowing the carbon dioxide-containing gas to flow in the same direction; a honeycomb structure carrying a carbon dioxide adsorbent, the honeycomb structure being disposed in series in the first gas flow passage and the second gas flow passage, Equipped with the first gas flow passage is heated so that a temperature of the honeycomb structures arranged therein is higher than a temperature of the honeycomb structures arranged in the second gas flow passage; a first mechanism is provided on the most upstream side of the first gas flow passage and the second gas flow passage, the first mechanism transporting the honeycomb structure at the most upstream of the second gas flow passage to the most upstream of the first gas flow passage and pushing out the honeycomb structure transported to the most upstream of the first gas flow passage to the downstream side of the first gas flow passage; A carbon dioxide concentrating apparatus characterized in that a second mechanism is provided at the most downstream side of the first gas flow path and the second gas flow path, which transports the honeycomb structure at the most downstream side of the first gas flow path to the most downstream side of the second gas flow path, and pushes the honeycomb structure transported to the most downstream side of the second gas flow path to the upstream side of the second gas flow path.

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