Carbon dioxide recovery device
Patent Information
- Application Number
- JP2024051688
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-27
- Publication Date
- 2025-10-09
Smart Images
Figure 2025150675000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a carbon dioxide capture device. [Background technology]
[0002] Conventionally, carbon dioxide capture devices have been known that capture carbon dioxide by drawing gases such as air containing carbon dioxide into a reactor that holds an adsorbent and adsorbing the carbon dioxide onto the adsorbent. Patent Document 1, for example, describes this type of technology. Patent Document 1 relates to a CO2 separation device for an internal combustion engine that heats the CO2 adsorbent and desorbs the CO2 adsorbed on the CO2 adsorbent without requiring an external supply of thermal energy. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Japanese Patent Publication No. 2022-152077 Summary of the Invention [Problem to be solved by the invention]
[0004] In carbon dioxide capture systems, the adsorbent material may be heated or cooled using a heat transfer medium such as LLC that has been heated or cooled by a heat pump. The LLC is heated or cooled using a separate heat transfer medium such as chlorofluorocarbon gas that flows inside the heat pump, so the system as a whole supplies thermal energy to the adsorbent material via two types of heat transfer medium.
[0005] When two types of heat transfer medium are used, the loss caused by heat exchange increases accordingly. It is possible to directly heat or cool the adsorbent using a heat transfer medium such as chlorofluorocarbon gas without using a heat transfer medium such as LLC. However, because the heat transfer medium such as chlorofluorocarbon gas in a heat pump is heated to a superheated state by compression, supplying it directly to the reactor could result in an unnecessarily high temperature, which could lead to deterioration of the adsorbent.
[0006] An object of the present invention is to provide a carbon dioxide capture device that prevents deterioration of an adsorbent due to a heat medium after compression by a compressor and reduces energy loss. [Means for solving the problem]
[0007] (1) The present invention relates to a system including a plurality of reactors (e.g., a first reactor 11a and a second reactor 11b described later) that contain an adsorbent (e.g., an adsorbent 12 described later) and perform an adsorption process in which a gas containing carbon dioxide is drawn into the adsorbent to adsorb the carbon dioxide, and a desorption process in which the adsorbent is heated under reduced pressure to desorb the carbon dioxide from the adsorbent; expansion valves (e.g., an expansion valve 71, a first expansion valve 71a, and a second expansion valve 71b described later) that expand and depressurize a heat medium supplied to the reactors that perform the adsorption process for cooling; and a compression valve (e.g., a compression valve 72, a first expansion valve 71a, and a second expansion valve 71b described later) that compress and pressurize the heat medium supplied to the reactors that perform the desorption process for heating. a compressor (for example, a compressor 72 described later) and a heat exchanger (for example, heat exchangers 75 and 75a described later) that cool the heat medium compressed by the compressor, the heat medium decompressed by the expansion valve is supplied to the reactor that performs the adsorption step, heat is exchanged between the heat medium and the reactor to cool the adsorbent and heat the heat medium, the heat medium compressed by the compressor is cooled by the heat exchanger and then supplied to a part of the reactor that cools the adsorbent that performs the desorption step, and heat is exchanged between the heat medium and the reactor to heat the adsorbent and cool the heat medium.
[0008] (2) In the carbon dioxide recovery device described in (1) above, the heat exchanger may perform heat exchange between the heat medium after being compressed by the compressor and before passing through the reactor that performs the desorption step, and the heat medium after passing through the reactor that performs the desorption step.
[0009] (3) In the carbon dioxide recovery device described in (1) above, the heat exchanger (for example, heat exchanger 75a described later) may perform heat exchange between the heat medium after being compressed by the compressor and before passing through the reactor that performs the desorption step, and the heat medium passing through a flow path of the heat medium inside the reactor (for example, flow path 76 described later).
[0010] (4) In the carbon dioxide recovery device described in (3) above, the flow path of the heat medium is configured by connecting a plurality of paths (for example, a first path 81, a second path 82, and a third path 83 described later) whose total number is odd, in a folded manner, and the heat exchanger may perform heat exchange between the heat medium that has passed through the path (for example, the second path 82 described later) that is one path before the final path (for example, the third path 83 described later) among the plurality of paths, and the heat medium after being compressed by the compressor. [Effects of the Invention]
[0011] According to the present invention, it is possible to provide a carbon dioxide capture device that prevents deterioration of the adsorbent due to the heat medium after compression by the compressor and has little energy loss. [Brief explanation of the drawings]
[0012] [Figure 1] 1 is a schematic diagram showing the configuration of a carbon dioxide capture device according to a first embodiment. [Figure 2] FIG. 2 is a circuit diagram illustrating a heat exchanger of the carbon dioxide recovery system according to the first embodiment. [Figure 3] FIG. 2 is a Mollier diagram illustrating heat transfer in the heat exchanger of the carbon dioxide recovery unit according to the first embodiment. [Figure 4] FIG. 10 is a circuit diagram illustrating a heat exchanger of a carbon dioxide recovery system according to a second embodiment. [Figure 5] FIG. 10 is a Mollier diagram illustrating heat transfer in a heat exchanger of a carbon dioxide recovery unit according to a second embodiment. [Figure 6]FIG. 10 is a schematic diagram showing a flow path of a heat medium in a reactor of a carbon dioxide capture device according to a third embodiment. [Figure 7] FIG. 10 is a diagram illustrating a configuration example of a fourth embodiment in which a path formed inside a reactor has a one-path configuration. [Figure 8] FIG. 10 is a diagram illustrating a configuration example of a fourth embodiment in which a path formed inside a reactor has a one-path configuration. DETAILED DESCRIPTION OF THE INVENTION
[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0014] First Embodiment Fig. 1 is a schematic diagram showing the configuration of a carbon dioxide capture device 1 according to the first embodiment. Fig. 2 is a circuit diagram illustrating a heat exchange device 70 of the carbon dioxide capture device 1 according to the first embodiment.
[0015] The carbon dioxide capture device 1 is applied to, for example, direct air capture (DAC) technology, which captures carbon dioxide from the atmosphere in order to reduce the carbon dioxide concentration in the atmosphere. The carbon dioxide captured by the carbon dioxide capture device 1 is stored underground or reused as fuel or material.
[0016] 1 and 2, the carbon dioxide capture device 1 includes a first reactor 11a, a second reactor 11b, an atmospheric air suction line 101, a blower 61, a first intake on-off valve 21, a second intake on-off valve 22, a first exhaust line 121, a first exhaust on-off valve 31, a second exhaust line 122, a second exhaust on-off valve 32, a carbon dioxide line 150, a vacuum pump 62, and a heat exchanger 70. Note that the heat exchanger 70 is not shown in FIG.
[0017] Both the first reactor 11a and the second reactor 11b contain an adsorbent 12 therein for adsorbing carbon dioxide. The adsorbent 12 is a particulate material that adsorbs carbon dioxide at low temperatures (for example, in the range of -30°C to 50°C) and desorbs (releases) carbon dioxide at high temperatures (for example, in the range of 50°C to 110°C) when the ambient carbon dioxide concentration is low. An example of such an adsorbent 12 is a solid amine carbon dioxide adsorbent formed by supporting an amine on a porous material such as silica.
[0018] The first reactor 11a and the second reactor 11b alternately perform an adsorption process in which carbon dioxide in a gas such as the air that has been taken in is adsorbed onto the adsorbent 12, and a desorption process in which a vacuum state is created and then reduced pressure and heating is performed to desorb the carbon dioxide adsorbed onto the adsorbent 12. In the example of Fig. 1, the adsorption process is performed in the first reactor 11a, while the desorption process is performed in the second reactor 11b.
[0019] The air suction line 101 is a pipe that sucks in gas such as the atmosphere containing carbon dioxide from an inlet 102 and sends it to the first reactor 11a or the second reactor 11b. The air suction line 101 has a first branch line 111 that branches off and is connected to the upstream side of the first reactor 11a, and a second branch line 112 that branches off and is connected to the upstream side of the second reactor 11b.
[0020] The blower 61 is disposed upstream of the branching portion of the first branch line 111 and the second branch line 112 of the atmosphere suction line 101. When driven, the blower 61 generates a gas flow from "intake" to "exhaust" through the atmosphere suction line 101 to the first reactor 11a or the second reactor 11b. This causes a gas containing carbon dioxide to be supplied into the first reactor 11a or the second reactor 11b.
[0021] The first intake on-off valve 21 is disposed in the first branch line 111. The first intake on-off valve 21 is controlled to an open state to open the path of the first branch line 111 in the adsorption process, and is controlled to a closed state to close the path of the first branch line 111 in the desorption process. In the example of Fig. 1, the first reactor 11a is performing the adsorption process, and therefore the first intake on-off valve 21 is controlled to an open state.
[0022] The second intake on-off valve 22 is disposed in the second branch line 112. The second intake on-off valve 22 is controlled to an open state to open the path of the second branch line 112 in the adsorption process, and is controlled to a closed state to close the path of the second branch line 112 in the desorption process. In the example of Fig. 1, the second reactor 11b is performing the desorption process, and therefore the second intake on-off valve 22 is controlled to a closed state.
[0023] The first exhaust line 121 is a pipe connected to the downstream side of the first reactor 11a. The first exhaust on-off valve 31 is disposed in the first exhaust line 121. The first exhaust on-off valve 31 is controlled to an open state to open the path of the first exhaust line 121 during the adsorption process, and is controlled to a closed state to close the path of the first exhaust line 121 during the desorption process. In the example of FIG. 1, the adsorption process is being performed in the first reactor 11a, and therefore the first exhaust on-off valve 31 is controlled to an open state. During adsorption, even if carbon dioxide is contained, the gas after adsorption is discharged to the outside through the first exhaust line 121.
[0024] The second exhaust line 122 is a pipe connected to the downstream side of the second reactor 11b. The second exhaust on-off valve 32 is disposed in the second exhaust line 122. The second exhaust on-off valve 32 is controlled to an open state that opens the path of the second exhaust line 122 during the adsorption process, and is controlled to a closed state that closes the path of the second exhaust line 122 during the desorption process. In the example of Fig. 1, the desorption process is being performed in the second reactor 11b, and therefore the second exhaust on-off valve 32 is controlled to a closed state.
[0025] The carbon dioxide line 150 is connected to the downstream side of each of the first reactor 11a and the second reactor 11b. The carbon dioxide line 150 is a pipe for recovering carbon dioxide desorbed in the desorption step, and high-concentration carbon dioxide flows through it.
[0026] The vacuum pump 62 is disposed in the carbon dioxide line 150. By driving the vacuum pump 62, the carbon dioxide desorbed in the desorption step of the first reactor 11a or the second reactor 11b is sucked in and collected.
[0027] Next, the configuration of the heat exchanger 70 will be described with reference to Fig. 2. The flow paths shown in Fig. 2 are conceptual diagrams showing the flow of the heat medium, and when the first reactor 11a transitions to the desorption step and the second reactor 11b transitions to the adsorption step, the positions of the first reactor 11a and the second reactor 11b are interchanged. As a means for switching the flow paths, known techniques such as branched piping paths and flow path switching valves can be used.
[0028] As shown in FIG. 2, the heat exchange device 70 includes a first heat exchange line 161, a second heat exchange line 162, a first expansion valve 71a, a second expansion valve 71b, a compressor 72, a heat exchanger 75, a first reactor 11a, and a second reactor 11b.
[0029] The first heat exchange line 161 is a flow path for the heat medium that supplies the heat medium to each of the first reactor 11a and the second reactor 11b. The heat medium is, for example, chlorofluorocarbon gas. In the first heat exchange line 161, a compressor 72, a heat exchanger 75, the second reactor 11b, a first expansion valve 71a, and the first reactor 11a are arranged in this order from upstream to downstream. The first heat exchange line 161 is configured as a circulation flow path in which the heat medium leaving the outlet of the compressor 72 finally returns to the inlet of the compressor 72.
[0030] The second heat exchange line 162 is a flow path for the heat medium that branches off from the first heat exchange line 161 downstream of the second reactor 11b and passes through a heat exchanger 75 to be connected to the first heat exchange line 161 downstream of the first reactor 11a. In the second heat exchange line 162, a second expansion valve 71b and a heat exchanger 75 are arranged in this order from upstream to downstream.
[0031] The first expansion valve 71a expands and reduces the pressure of the heat medium supplied to the first reactor 11a that performs the adsorption step. This reduces the temperature of the heat medium. In this embodiment, the pressure is reduced by expansion of the heat medium that has been cooled by heating in the second reactor 11b.
[0032] The second expansion valve 71b expands the heat medium flowing through the second heat exchange line 162, not through the first heat exchange line 161, which is connected from the second reactor 11b that performs the desorption step to the first expansion valve 71a. The heat medium flowing through the second heat exchange line 162 flows into the heat exchanger 75 in a cooled state due to the pressure reduction of the second expansion valve 71b.
[0033] The compressor 72 heats, by compression, the heat medium flowing through the first heat exchange line 161. The compressor 72 of the first embodiment compresses the heat medium that is a mixture of the heat medium that has passed through the first reactor 11a and the heat medium that has passed through the second expansion valve 71b and the heat exchanger 75 in the second heat exchange line 162.
[0034] The heat exchanger 75 exchanges heat between the heat medium compressed and heated by the compressor 72 and the heat medium that has been subjected to heat exchange in the second reactor 11b and then decompressed and cooled by the second expansion valve 71b. As a result, the heat medium compressed by the compressor 72 is cooled by the heat exchanger 75 to a temperature (e.g., 80°C) that does not deteriorate the adsorbent 12 before flowing into the second reactor 11b that performs the desorption step. The heat medium that leaves the heat exchanger 75 returns to the compressor 72 in a state heated by the heat exchanger 75.
[0035] The first reactor 11a is supplied with a heat medium cooled by a first expansion valve 71a to cool the adsorbent 12. Heat exchange between the adsorbent 12 and the heat medium cools the adsorbent 12 and heats the heat medium. The first reactor 11a functions as an evaporator that evaporates the liquefied heat medium.
[0036] In the second reactor 11b, a heat medium heated by a compressor 72 is supplied to heat the adsorbent 12. By heat exchange between the adsorbent 12 and the heat medium, the adsorbent 12 is heated and the heat medium is cooled. The second reactor 11b functions as a condenser that condenses the vaporized heat medium.
[0037] 3 is a Mollier diagram illustrating heat transfer in the heat exchanger 70 of the carbon dioxide recovery system 1 according to the first embodiment. The horizontal axis represents specific enthalpy calculated from the temperature and pressure of the heat medium, while the vertical axis represents pressure. In the first heat exchange line 161 in FIG. 2, P1 represents the position before the inlet of the compressor 72, P2 represents the position between the compressor 72 and the heat exchanger 75, P3 represents the position between the heat exchanger 75 and the second reactor 11b, P4 represents the position of the branching portion of the second heat exchange line 162, P5 represents the position between the first expansion valve 71a and the first reactor 11a, and P6 represents the position after the outlet of the first reactor 11a. In the second heat exchange line 162, P7 represents the position between the second expansion valve 71b and the heat exchanger 75, and P8 represents the position between the heat exchanger 75 and the junction of the first heat exchange line 161. The high-temperature, high-pressure superheated gas discharged from the compressor is cooled in heat exchanger 75, and in a state where the temperature of the overheated gas region drops from P2 to P3, heat is absorbed by the adsorbent in the second reactor (condenser) of the desorption process, and the gas is cooled to P4. After P4, a portion of the heat medium flows into second heat exchange line 162, and the pressure is reduced to intermediate pressure P7 by second expansion valve 71b, where the gas exchanges heat with the high-temperature, high-pressure superheated gas discharged from the compressor, passes through the state of P8, and merges with compressor intake air P1.
[0038] Second Embodiment Next, a description will be given of the configuration of a carbon dioxide capture device 1 according to a second embodiment, which has a flow path configuration different from that of the first embodiment. In the following description, the same reference numerals will be used to designate components that are common to or similar to the above embodiments, and detailed description thereof may be omitted.
[0039] Fig. 4 is a circuit diagram illustrating a heat exchanger 70a of a carbon dioxide recovery system 1 according to the second embodiment. Note that the flow path shown in Fig. 4 is also a conceptual diagram showing the flow of the heat medium, and in a state where the first reactor 11a transitions to the desorption step and the second reactor 11b transitions to the adsorption step, the positions of the first reactor 11a and the second reactor 11b are interchanged.
[0040] As shown in FIG. 4, the heat exchange device 70a includes a first heat exchange line 171, a second heat exchange line 172, an expansion valve 71, a compressor 72, a heat exchanger 75, a first reactor 11a, and a second reactor 11b.
[0041] The first heat exchange line 171 is a flow path for the heat medium that supplies the heat medium to each of the first reactor 11a and the second reactor 11b. The heat medium is, for example, chlorofluorocarbon gas. The first heat exchange line 171 is arranged, in this order from upstream to downstream, with a compressor 72, a heat exchanger 75, the second reactor 11b, an expansion valve 71, and the first reactor 11a. The first heat exchange line 171 is a circulation flow path in which the heat medium exiting the outlet of the compressor 72 finally returns to the inlet of the compressor 72.
[0042] The second heat exchange line 172 is a flow path for a heat medium that branches off from the first heat exchange line 171 downstream of the first reactor 11a and connects to the first heat exchange line 171 upstream of the compressor 72 via a heat exchanger 75.
[0043] The expansion valve 71 reduces the pressure of the heat medium that has been cooled by heating in the second reactor 11b through expansion, thereby cooling the heat medium.
[0044] The compressor 72 compresses and heats the heat medium flowing through the first heat exchange line 171. The compressor 72 of the second embodiment compresses a heat medium that is a mixture of the heat medium that has passed through the first reactor 11a and the heat medium that has passed through the heat exchanger 75 in the second heat exchange line 172.
[0045] The heat exchanger 75 exchanges heat between the heat medium compressed and heated by the compressor 72 and the heat medium that has undergone heat exchange in the first reactor 11a. As a result, the heat medium compressed by the compressor 72 is cooled by the heat exchanger 75 to a temperature (e.g., 80°C) that does not deteriorate the adsorbent 12 before flowing into the second reactor 11b that performs the desorption step. In addition, the heat medium that returns to the compressor 72 via the heat exchanger 75 is heated by heat exchange with the heat exchanger 75.
[0046] In the second embodiment as well, the first reactor 11a functions as an evaporator that evaporates the liquefied heat medium, and the second reactor 11b functions as a condenser that condenses the vaporized heat medium.
[0047] 5 is a Mollier diagram illustrating heat transfer in the heat exchanger 70a of the carbon dioxide recovery system 1 according to the second embodiment. In the first heat exchange line 171 in FIG. 4, P1 denotes a position before the inlet of the compressor 72, P2 denotes a position between the compressor 72 and the heat exchanger 75, P3 denotes a position between the heat exchanger 75 and the second reactor 11b, P4 denotes a position between the second reactor 11b and the expansion valve 71, P5 denotes a position between the expansion valve 71 and the first reactor 11a, and P6 denotes a position after the outlet of the first reactor 11a. A portion of the heat medium that has become a low-temperature, low-pressure gas after leaving the first reactor 11a (as a heat exchanger) is introduced into the second heat exchange line 172 and heat-exchanges with the high-temperature, high-pressure discharge gas P2 discharged from the compressor 72, thereby allowing the heat medium to be cooled to P3 and introduced into the second reactor 11b.
[0048] The carbon dioxide recovery device 1 of the present embodiment described above includes a plurality of first reactors 11a and second reactors 11b that have an adsorbent 12 therein and perform an adsorption process in which a gas containing carbon dioxide is drawn into the adsorbent 12 to adsorb the carbon dioxide, and a desorption process in which the adsorbent 12 is heated under a reduced pressure around the adsorbent 12 to desorb the carbon dioxide from the adsorbent 12; an expansion valve 71 or a first expansion valve 71a that expands and reduces the pressure of a heat medium supplied for cooling to the first reactor 11a that performs the adsorption process; and a heat medium supplied for heating to the second reactor 11b that performs the desorption process. The heat medium compressed by the compressor 72 is cooled by the heat exchanger 75 and then supplied to a portion of the second reactor 11b that cools the adsorbent 12, where the desorption step is performed, and heat exchange is performed between the heat medium and the second reactor 11b, where the adsorbent 12 is heated and the heat medium is cooled.
[0049] As a result, the adsorbent 12 in the second reactor 11b can be directly heated during the desorption step by a heat medium such as chlorofluorocarbon gas compressed by the compressor 72, without using a refrigerant such as LLC (Long Life Coolant), and the first reactor 11a can be cooled during the adsorption step. Furthermore, the heat medium supplied to the inside of the second reactor 11b is cooled by the heat exchanger 75, which functions as a temperature adjustment means, so as not to reach a temperature that would deteriorate the adsorbent 12, while maintaining a good gas-liquid two-phase state at a temperature that allows the adsorbent 12 to be appropriately heated. In this way, the configuration of the carbon dioxide recovery system 1 of this embodiment makes it possible to prevent deterioration of the adsorbent 12 and improve energy efficiency at the same time.
[0050] In addition, in this embodiment, the heat exchanger 75 exchanges heat between the heat medium after being compressed by the compressor 72 and before passing through the second reactor 11b that performs the desorption process, and the heat medium after passing through the second reactor 11b that performs the desorption process.
[0051] This allows the temperature of the heat medium flowing into the second reactor 11b during the desorption step to be adjusted by the heat exchanger 75 within the circuit of the heat exchanger 70 (heat exchanger 70a). Even if the first reactor 11a or the second reactor 11b is configured such that the heat exchanger 75 cannot be disposed therein, the heat medium compressed by the compressor 72 outside the first reactor 11a or the second reactor 11b can be adjusted to a temperature that will not cause deterioration of the adsorbent 12 and will allow the adsorbent 12 to be appropriately heated.
[0052] In both the first and second embodiments, heat exchange is performed by the heat exchanger 75 outside the first reactor 11a and the second reactor 11b, but the present invention is not limited to this configuration. An embodiment in which the heat exchanger 75 is not disposed outside the first reactor 11a and the second reactor 11b will be described.
[0053] Third Embodiment Fig. 6 is a schematic diagram showing a flow path 76 of the heat medium in the reactor 11c of the carbon dioxide recovery system 1 according to the third embodiment. It is assumed that the reactor 11c shown in Fig. 6 is performing the desorption step.
[0054] As shown in Fig. 6, a heat exchanger 75a that cools the heat medium compressed by the compressor 72 is disposed inside or near the reactor 11c. The heat medium, which is a high-temperature superheated gas compressed by the compressor 72, is cooled by the heat exchanger 75a. For example, the heat medium is cooled from 110°C to about 82°C. Note that the heat exchange by the heat exchanger 75a is preferably performed so that the gas temperature of the heat medium is within +2°C of the vicinity of the saturation temperature.
[0055] The reactor 11c of the third embodiment has a front section 80, a flow path 76, and a rear section 84.
[0056] The front stage 80 is an inlet of the flow path 76 of the heat medium that exchanges heat with the adsorbent 12. By passing through the front stage 80, the heat medium is cooled from 92°C to about 80°C.
[0057] The flow path 76 is a section where the heat medium exchanges heat with the adsorbent 12. The flow path 76 has a plurality of paths, including a first path 81, a second path 82, and a third path 83, and the total number of paths is an odd number. The first path 81 and the second path 82 are connected in a folded manner, and the second path 82 and the third path 83 are also connected in a folded manner. This results in a layout in which the inlet side of the first path 81, where the heat medium first flows into the flow path 76, is on the opposite side from the outlet side of the third path 83, where the heat medium flows out of the flow path 76.
[0058] The first path 81 is a flow path for the heat medium connected to the front-stage section 80. The heat medium passing through the first path 81 reaches a temperature of about 80°C. The inside of the first path 81 is a constant region where the temperature of the heat medium becomes a gas-liquid two-layer state at about 80°C.
[0059] The second path 82 is a flow path through which the heat transfer medium passes after passing through the first path 81. The interior of the second path 82 also becomes a constant region where the temperature is about 80°C, where the heat transfer medium is in a gas-liquid two-layer state.
[0060] The heat medium after passing through the second pass 82 passes through the heat exchanger 75a and flows into the third pass 83. By passing through the first pass 81 and the second pass 82, the temperature of the heat medium is reduced, and the proportion of the gas phase in the gas-liquid two-phase state is reduced (for example, 10%). In this regard, in the present embodiment, the heat medium after passing through the second pass 82 is heated to a high temperature by being compressed by the compressor 72 before entering the reactor 11c, and thereby the temperature is raised to about 80°C and the proportion of the gas phase is increased (for example, 30%). This makes it possible to make the gas-liquid two-phase state of the heat medium entering the third pass 83 more appropriate.
[0061] The third pass 83 is the final flow path through which the heat medium passes after passing through the second pass 82 and being heated in the heat exchanger 75a. When the total number of passes is odd, as in the third embodiment, heat exchange occurs between the heat medium that passed through the second pass 82, which is the final pass before the third pass 83. As described above, the heat medium that has been cooled by passing through the first pass 81 and the second pass 82 is heated in the heat exchanger 75a, and the temperature inside the third pass 83 also reaches a constant region of about 80°C where the heat medium is in a gas-liquid two-layer state.
[0062] The rear stage 84 is an outlet of the flow path 76 where the heat transfer medium passes through the third path 83 and exits the reactor 11c. In the rear stage 84, the heat transfer medium is in a supercooled liquid phase region of about 70°C.
[0063] In the third embodiment described above, the heat exchanger 75a exchanges heat between the heat medium compressed by the compressor 72 and before passing through the reactor 11c that performs the desorption process, and the heat medium passing through the heat medium flow path 76 inside the reactor 11c.
[0064] This allows the heat medium cooled by heat exchange with the adsorbent 12 inside the reactor 11c to be used to cool the heat medium compressed by the compressor 72. Furthermore, the heat medium inside the reactor 11c is heated by heat exchange with the heat exchanger 75a while passing through the flow path 76, which prevents the temperature of the heat medium from decreasing too much in the latter half of the flow path 76, thereby preventing the balance between the gas-liquid two-phase state from being lost, and realizing a uniform temperature and a good gas-liquid two-phase state throughout the entire flow path 76 inside the reactor 11c.
[0065] In the third embodiment, the heat medium flow path 76 is formed by connecting a first path 81, a second path 82, and a third path 83, the total of which is an odd number, in a folded manner, and the heat exchanger 75a exchanges heat between the heat medium that has passed through the second path 82, which is one path before the third path 83, which is the final path, and the heat medium that has been compressed by the compressor 72.
[0066] As a result, by connecting the multiple paths in a folded manner, the internal space of the reactor 11 can be effectively utilized, ensuring a sufficient flow path length for heat exchange with the adsorbent 12. Furthermore, since the number of paths is odd, the position where heat exchange occurs before the final path is the inlet side of the flow path 76 of the reactor 11c. If heat exchange before the final path were to occur on the outlet side of the flow path 76, it would be necessary to route piping to the inlet side of the final path. However, in the configuration of this embodiment, it is sufficient to place the heat exchanger 75a in the folded portion before the final path, which allows for simpler routing of piping, etc.
[0067] The reactor 11c of the third embodiment has a configuration including multiple paths, namely, a first path 81, a second path 82, and a third path 83, but is not limited to this configuration. The method of stacking multiple heat exchangers is not particularly limited, and thermal connection can be achieved with an appropriate structure depending on the layout. For example, the number of paths formed inside the reactor can be configured as one path. This configuration will be described later.
[0068] Furthermore, the maintenance intervals for replacing the adsorbent 12 may be managed by a computer such as a control device so as to be divided by temperature grade depending on the position in the flow path 76 inside the reactor 11c. For example, the maintenance intervals may be shorter in the front stage 80 and first pass 81 through which a high-temperature heat medium passes, and longer in the second pass 82, third pass 83, and rear stage 84, which are located downstream.
[0069] Furthermore, in the third embodiment, materials with different desorption characteristics can be used for each path. For example, the adsorbent 12 at the position corresponding to the front stage 80 or the first path 81 may be filled with a material that has a high upper limit of heat resistance and requires high-temperature desorption.
[0070] <Fourth embodiment> 7 and 8 are diagrams illustrating a configuration example of a fourth embodiment in which a path formed inside the reactor has a one-path configuration. In the example of Fig. 7 and Fig. 8, a first reactor 11A, a second reactor 11B, and a third reactor 11C are arranged adjacent to each other. The first reactor 11A, the second reactor 11B, and the third reactor 11C each have a one-path configuration in which flow paths 81a, 81b, and 81c proceed in one direction from one side to the other without turning back within the reactor.
[0071] Headers 210, 220 are provided at the inlet and outlet sides of the heat transfer medium to each reactor. A plurality of supply lines 301 and discharge lines 302 are arranged adjacent to the headers 210, 220. The supply line 301 is connected to each of the first reactor 11A, the second reactor 11B, and the third reactor 11C, and supplies the high-temperature heat transfer medium from the compressor to each reactor. The discharge line 302 is connected to each of the first reactor 11A, the second reactor 11B, and the third reactor 11C, and discharges the heat transfer medium cooled in each reactor.
[0072] Furthermore, the first reactor 11A and the third reactor 11C are arranged such that the supply line 301 and the discharge line 302 are provided in the opposite directions to the second reactor 11B. That is, in the header 210, the discharge line 302 of the second reactor 11B is sandwiched between the supply line 301 of the first reactor 11A and the supply line 301 of the third reactor 11C. In addition, in the header 220, the supply line 301 of the second reactor 11B is sandwiched between the discharge line 302 of the first reactor 11A and the discharge line 302 of the third reactor 11C. Furthermore, the supply line 301 and the discharge line 302 are configured to be in thermal contact with each other so as to function as a heat exchanger within the headers 210 and 220. This configuration allows the overheated gas (heat medium) upstream of the reactor 11 to be cooled and supplied to the reactor 11, making it possible to suppress the temperature of the overheated gas flowing into each heat exchanger (reactor 11).
[0073] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications. Furthermore, the effects described in the above embodiments are merely preferred effects, and the present invention is not limited to those described in the above embodiments. [Explanation of symbols]
[0074] 1. Carbon dioxide capture device 11a First Reactor 11b Second Reactor 11c Reactor 11A First Reactor 11B Second Reactor 11C Third Reactor 12 Adsorbent 70 Heat exchange equipment 70a heat exchange equipment 71 Expansion valve 71a First expansion valve 71b Second expansion valve 72 Compressor 75 Heat exchanger 75a heat exchanger 76 Flow path 81 First Pass 82 2nd pass 83 Third Pass
Claims
1. a plurality of reactors each having an adsorbent therein, each reactor performing an adsorption step of drawing a gas containing carbon dioxide into the adsorbent to adsorb the carbon dioxide, and a desorption step of heating the adsorbent under a reduced pressure around the adsorbent to desorb the carbon dioxide from the adsorbent; an expansion valve that expands and reduces the pressure of a heat medium that is supplied for cooling to the reactor that performs the adsorption step; a compressor that compresses and pressurizes the heat medium that is supplied to the reactor that performs the desorption step for heating; a heat exchanger that cools the heat medium compressed by the compressor; Equipped with the heat medium decompressed by the expansion valve is supplied to the reactor performing the adsorption step, and heat exchange is performed between the heat medium and the reactor to cool the adsorbent and heat the heat medium. the heat medium compressed by the compressor is cooled by the heat exchanger and then supplied to a portion of the reactor that cools the adsorbent, where the desorption step is performed, and heat exchange is performed between the heat medium and the reactor to heat the adsorbent and cool the heat medium. Carbon dioxide capture equipment.
2. The heat exchanger comprises: the heat transfer medium after being compressed by the compressor and before passing through the reactor that performs the desorption step; the heat transfer medium after passing through the reactor that performs the desorption step; Heat exchange takes place between The carbon dioxide capture device according to claim 1 .
3. The heat exchanger comprises: the heat transfer medium after being compressed by the compressor and before passing through the reactor that performs the desorption step; the heat transfer medium passing through a flow path of the heat transfer medium inside the reactor; Heat exchange takes place between The carbon dioxide capture device according to claim 1 .
4. The flow path of the heat transfer medium inside the reactor is It is composed of multiple paths that sum to an odd number and are connected by folding back. The heat exchanger comprises: The heat medium has passed through the path immediately before the final path among the plurality of paths; and the heat medium after being compressed by the compressor; Heat exchange takes place between The carbon dioxide capture device according to claim 3 .