Carbon dioxide recovery device

Abstract

To provide a carbon dioxide recovery device which has high energy efficiency enough to suppress energy required for rise of a temperature of an adsorption material in a desorption step.SOLUTION: A carbon dioxide recovery device 1 includes: a plurality of modules 11 which have adsorption materials 12 therein, and execute an adsorption step of sucking gas containing carbon dioxide, and making the adsorption material 12 adsorb the carbon dioxide, and a desorption step of heating the periphery of the adsorption material 12 in a decompressed state, and thereby desorbing the carbon dioxide from the adsorption material 12; a heat exchanger 80 for supplying heat for heating the adsorption material 12 to each of the plurality of modules 11 through a heating medium; and a bypass route 31 which connects a first module 11A which is one module of the plurality of modules 11 and a second module 11B different from the first module 11A, and makes the heat medium to flow therein.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a carbon dioxide recovery device.

Background Art

[0002] Conventionally, a technique for recovering carbon dioxide from a gas containing carbon dioxide such as the atmosphere has been known. For example, Patent Document 1 describes this type of technique. Patent Document 1 describes a method of separating gaseous carbon dioxide from a gas mixture by cyclic adsorption / desorption using an adsorbent that adsorbs gaseous carbon dioxide.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the desorption step of desorbing carbon dioxide adsorbed on the adsorbent from the adsorbent, it is necessary to bring the adsorbent to a high temperature state. In order to raise the temperature of the adsorbent from room temperature to a desorbable temperature, a large amount of thermal energy is required from the outside. There was room for improvement in the prior art in terms of improving the energy efficiency required for raising the temperature of the adsorbent.

[0005] An object of the present invention is to provide a highly energy-efficient carbon dioxide recovery device capable of suppressing the energy required for raising the temperature of the adsorbent in the desorption step.

Means for Solving the Problems

[0006] (1) The present invention includes an adsorption material (for example, the adsorption material 12 described later) inside, an adsorption step of sucking a gas containing carbon dioxide into the adsorption material to adsorb the carbon dioxide, and a desorption step of desorbing the carbon dioxide from the adsorption material by heating the periphery of the adsorption material under a reduced pressure state. It also includes a plurality of modules (for example, the module 11 described later) that execute these steps, a heat exchange device (for example, the heat exchange device 80 described later) that supplies heat for heating the adsorption material to each of the plurality of modules via a heat medium, and a bypass path (for example, the bypass path 31 described later) that connects a first module (for example, the first module 11A described later) which is one of the plurality of modules and a second module (for example, the second module 11B described later) different from the first module and through which the heat medium can flow. It is a carbon dioxide recovery device (for example, the carbon dioxide recovery device 1 described later).

[0007] (2) In the carbon dioxide recovery device described in (1) above, the heat medium that has cooled the first module after the desorption step may be supplied to the second module that is heated up in the desorption step through the bypass path, so that heat can be supplied from the first module to the second module.

[0008] (3) The carbon dioxide recovery device described in (1) or (2) above may further include a hot water tank (for example, the hot water tank 83 described later) that is arranged between the heat exchange device and the module and stores hot water as the heat medium.

[0009] (4) In the carbon dioxide recovery device described in (3) above, after heating the adsorption material by supplying heat from the first module to the second module via the bypass path, the temperature of the adsorption material may be increased by two-stage heating in which heat is supplied from the hot water tank to the second module to heat the adsorption material.

[0010] (5) In the carbon dioxide recovery device according to (4) above, when the temperature difference between the adsorbent of the first module during cooling after the desorption step and the adsorbent of the second module whose temperature is to be raised in the desorption step is equal to or greater than a certain value, heat is supplied from the first module to the second module through the bypass path. When the temperature difference between the adsorbent of the first module during cooling and the adsorbent of the second module whose temperature is to be raised becomes less than a certain value, the bypass path may be closed and heat supply from the hot water tank may be started.

[0011] (6) The carbon dioxide recovery device according to (1) or (2) above further includes a fan (for example, the fan 61 described later) that supplies gas to the inside of the module, a heat source (for example, the heat exchanger 80 described later) that performs heat supply for heating the adsorbent of the module, and a vacuum pump (for example, the vacuum pump 62 and the carbon dioxide recovery pump 63 described later) that sucks the gas inside the module. At least one of the fan, the heat source, and the vacuum pump is shared by the plurality of modules. The number M of the modules connected in series by the bypass path may be set based on the following mathematical formula (1), where N is a natural number and R is the ratio of the adsorption time of the adsorbent to the desorption time. M = N × (R + 1) ··· Mathematical formula (1)

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a carbon dioxide recovery device with high energy efficiency that can suppress the energy required for raising the temperature of the adsorbent in the desorption step.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0015] <Overall Configuration> FIG. 1 is a schematic diagram showing the configuration related to the liquid flow of the carbon dioxide recovery device 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration related to the gas flow of the module 11 of the carbon dioxide recovery device 1 of the present embodiment. In addition, the illustration of the configuration related to the gas flow of the carbon dioxide recovery device 1 is omitted in FIG. 1.

[0016] The carbon dioxide recovery device 1 of this embodiment is applied to, for example, direct air capture technology (DAC) that recovers carbon dioxide in the atmosphere in order to reduce the carbon dioxide concentration in the atmosphere. The carbon dioxide recovered by the carbon dioxide recovery device 1 is stored underground or reused as fuel or material.

[0017] As shown in FIGS. 1 and 2, the carbon dioxide recovery device 1 of this embodiment includes a module unit 10, a fan 61, a vacuum pump 62, a carbon dioxide recovery pump 63, and a heat exchanger 80.

[0018] The module unit 10 is configured by arranging a plurality of modules 11 that adsorb carbon dioxide in parallel. In this embodiment, a total of 16 modules 11 are arranged by a pair of left and right module units 10.

[0019] As shown in FIG. 2, the module 11 is a carbon dioxide recovery module including an adsorbent 12, a first valve 21, a second valve 22, a third valve 23, a fourth valve 24, and a temperature sensor 27.

[0020] The adsorbent 12 is disposed inside the module 11 to adsorb carbon dioxide. The adsorbent 12 is a particulate member and has the property of adsorbing carbon dioxide in a low temperature state (for example, in the range of -30°C to 50°C) and desorbing (releasing) carbon dioxide in a high temperature state (for example, in the range of 50°C to 110°C) and a state where the concentration of ambient carbon dioxide is low. Examples of such an adsorbent 12 include a solid amine carbon dioxide adsorbent in which an amine is supported on a porous material such as silica.

[0021] The first valve 21 is an on-off valve disposed at the connection part between the carbon dioxide line 103 for recovering carbon dioxide and the module 11. A carbon dioxide recovery pump 63 is disposed in the carbon dioxide line 103. The second valve 22 is an on-off valve disposed at the connection part between the vacuum line 102 where the vacuum pump 62 is disposed and the module 11. The third valve 23 is an on-off valve disposed at the inlet for taking in air or the like into the module 11. The fourth valve 24 is an on-off valve disposed at the connection part between the adsorption line 101 and the module 11. A fan 61 is disposed in the adsorption line 101.

[0022] The first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 are all controlled to be opened and closed by the control device 90. The first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 are constituted by, for example, normally open butterfly valves. The temperature sensor 27 measures the temperature of the adsorbent 12. The measurement information of the temperature sensor 27 is transmitted to the control device 90.

[0023] The adsorption line 101 is branched and connected to each of the modules 11. The fan 61 is disposed at the part where the branched parts of the adsorption line 101 converge. When the fan 61 is driven, a gas flow from "intake air" to "exhaust air" is generated in the module 11 through the adsorption line 101. Thereby, air is supplied into the module 11.

[0024] The vacuum line 102 is branched and connected to each of the modules 11. The vacuum pump 62 is disposed at the part where the branched parts of the vacuum line 102 converge. When the vacuum pump 62 is driven, the gas inside the module 11 is sucked through the vacuum line 102, and the inside of the module 11 is brought into a vacuum state or close to a vacuum state.

[0025] The carbon dioxide line 103 is branched and connected to each of the modules 11. A carbon dioxide recovery pump 63 is arranged at the portion where the branched portions of the carbon dioxide line 103 converge. The carbon dioxide recovery pump 63 applies a suction force to the carbon dioxide flowing through the carbon dioxide line 103 and stores the recovered carbon dioxide in a tank (not shown) for storing carbon dioxide.

[0026] Returning to FIG. 1, the heat exchanger 80 will be described. The heat exchanger 80 supplies thermal energy for heating the inside of each module 11 to a predetermined temperature when each module 11 of the module unit 10 performs the desorption process. Further, the heat exchanger 80 recovers unnecessary thermal energy when each module 11 performs the adsorption process.

[0027] The heat exchanger 80 of the present embodiment includes a heat exchanger 81, a cold water tank 82, a cold water line 111, a hot water tank 83, a hot water line 112, a three-way valve 30, a bypass path 31, and a bypass valve 32.

[0028] The heat exchanger 81 performs heat exchange between the heat medium flowing through the cold water line 111 and the heat medium flowing through the hot water line 112. The heat exchanger 81 is, for example, a heat pump. The heat medium is, for example, a liquid such as water. Due to the heat transfer occurring in the heat exchanger 81, the heat medium flowing through the cold water line 111 is cooled, and the heat medium flowing through the hot water line 112 is heated.

[0029] The cold water tank 82 stores the heat medium flowing through the cold water line 111. The heat medium flowing through the cold water line 111 is stored in the cold water tank 82 and then sent to the heat exchanger 81. Further, the heat medium cooled by the heat exchanger 81 is returned to the cold water tank 82 and then sent to each module 11 through the cold water line 111. A water pump 821 for heat exchanger circulation is arranged between the cold water tank 82 and the heat exchanger 81 in the cold water line 111. By driving the water pump 821 for heat exchanger circulation, the heat medium flowing through the cold water line 111 circulates between the cold water tank 82 and the heat exchanger 81.

[0030] The cold water line 111 is branched and connected to the upstream side and the downstream side of each module 11, connecting the cold water tank 82 and each module 11. Also, between the cold water tank 82 and each module 11 in the cold water line 111, a first water pump 822 for cold water circulation and a second water pump 823 for cold water circulation are arranged. Further, in the cold water line 111, a circulation line 824 that returns from the downstream side to the upstream side of the second water pump 823 for cold water circulation is arranged. A circulation valve 825 is arranged in this circulation line 824.

[0031] The hot water tank 83 stores the heat medium flowing through the hot water line 112. The heat medium flowing through the hot water line 112 is stored in the hot water tank 83 and then sent to the heat exchanger 81. Also, the heat medium heated by the heat exchanger 81 is returned to the hot water tank 83 and then sent to each module 11 through the hot water line 112. A water pump 831 for heat exchanger circulation is arranged between the hot water tank 83 and the heat exchanger 81 in the hot water line 112. By driving the water pump 831 for heat exchanger circulation, the heat medium flowing through the hot water line 112 circulates between the hot water tank 83 and the heat exchanger 81.

[0032] The hot water line 112 is branched and connected to the upstream side and the downstream side of each module 11, connecting the hot water tank 83 and each module 11. Also, between the hot water tank 83 and each module 11 in the hot water line 112, a first water pump 832 for hot water circulation and a second water pump 833 for hot water circulation are arranged. Further, in the hot water line 112, a circulation line 834 that returns from the downstream side to the upstream side of the second water pump 833 for hot water circulation is arranged. A circulation valve 835 is arranged in this circulation line 834.

[0033] The three-way valve 30 is connected to the cold water line 111, the hot water line 112, and the module 11. The three-way valve 30 is disposed on each of the upstream side and the downstream side of the module 11. The three-way valve 30 is configured to be able to switch between a cold water connection state in which the cold water line 111 is connected to the module 11, a hot water connection state in which the hot water line 112 is connected to the module 11, and a shut-off state in which the connection between the cold water line 111, the hot water line 112, and the module 11 is blocked.

[0034] The flow path switching of the three-way valve 30 is controlled by the control device 90. The heat medium is introduced into the module 11 through the three-way valve 30 disposed on the upstream side, and the heat medium is returned to the heat exchanger 81 side through the three-way valve 30 disposed on the downstream side.

[0035] The bypass path 31 is a flow path that enables the movement of the heat medium between the modules 11. The bypass path 31 connects between two modules 11. The modules 11 connected by the bypass path 31 may be adjacent modules or may be modules 11 at non-adjacent and separated positions. Details of the connection structure of this bypass path 31 will be described later.

[0036] The bypass valve 32 is disposed in the bypass path 31. The bypass valve 32 is disposed in each of the plurality of bypass paths 31. The bypass valve 32 is controlled to be opened and closed by the control device 90.

[0037] Next, the control device 90 will be described. The control device 90 controls the operations of each part of the carbon dioxide recovery device 1. The control device 90 controls operations such as driving and stopping devices used for adsorption and desorption of carbon dioxide. The control device 90 performs opening and closing control of the first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 provided in each module 11, and opening and closing control of each bypass valve 32. Further, the control device 90 performs driving control of the fan 61, the vacuum pump 62, the carbon dioxide recovery pump 63, the water pump 821 for heat exchanger circulation, the first water pump 822 for cold water circulation, the second water pump 823 for cold water circulation, the water pump 831 for heat exchanger circulation, the first water pump 832 for warm water circulation, the second water pump 833 for warm water circulation, etc., and opening and closing control of the circulation valve 825 and the circulation valve 835.

[0038] The control device 90 is a computer having, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The control device 90 may be composed of one unit or a plurality of units.

[0039] <Recovery of Carbon Dioxide> Next, the control for recovering carbon dioxide by the control device 90 will be described. The carbon dioxide recovery device 1 alternately performs an adsorption step of adsorbing carbon dioxide in a gas such as inhaled air onto the adsorbent 12 in the module 11 and a desorption step of desorbing the carbon dioxide adsorbed on the adsorbent 12, and removes and recovers carbon dioxide from the air by compressing the desorbed carbon dioxide and storing it in a tank (not shown). In this embodiment, the adsorption step and the desorption step are performed with the time of the adsorption step: the time of the desorption step = 3:1.

[0040] The adsorption process is a process of adsorbing carbon dioxide onto the adsorbent 12 in the module 11. In the adsorption process, the third valve 23 and the fourth valve 24 of the module 11 are opened, and the first valve 21 and the second valve 22 are closed. The fan 61 is driven to generate a gas flow from upstream to downstream, and the gas containing carbon dioxide (for example, air) is sucked in through the third valve 23. The sucked gas passes through the adsorbent 12 in the module 11. At this time, the inside of the module 11 is at room temperature (25 °C), and the carbon dioxide in the gas is adsorbed by the adsorbent 12. Gases other than carbon dioxide, such as nitrogen and oxygen, are exhausted to the outside of the carbon dioxide recovery device 1 through the fourth valve 24 and the adsorption line 101.

[0041] The desorption process is a process of desorbing carbon dioxide from the adsorbent 12 in the module 11. In the desorption process, the first valve 21, the third valve 23 and the fourth valve 24 of the module 11 are closed, and the second valve 22 is opened. The vacuum pump 62 operates to suck the inside of the module 11 and reduce the pressure to a vacuum state or close to a vacuum state. At the same time, the heat exchange device 80 allows the heat medium serving as a heat source to flow through the module 11 to supply heat energy and raise the temperature of the adsorbent 12 in the module 11. The temperature increase control by this heat exchange device 80 will be described later.

[0042] By controlling the temperature increase of the adsorbent 12, the adsorbent 12 is also heated to a predetermined temperature (for example, 80 °C) sufficient for the desorption process, and the carbon dioxide adsorbed on the adsorbent 12 is desorbed. Next, the second valve 22, the third valve 23 and the fourth valve 24 are closed, the first valve 21 is opened, and the carbon dioxide recovery pump 63 is driven, and the desorbed carbon dioxide is stored in a tank (not shown) through the carbon dioxide line 103. In this embodiment, among the 16 modules 11, 12 perform the adsorption process and the remaining 4 perform the desorption process, and each process is controlled accordingly.

[0043] <Temperature Increase Control of Adsorbent> The temperature rise control of the adsorbent 12 will be described. FIG. 3 is a schematic diagram showing the heat supply path in the first stage of the temperature rise of the adsorbent 12, FIG. 4 is a schematic diagram showing the heat supply path in the second stage of the temperature rise of the adsorbent 12, and FIG. 5 is a schematic diagram showing the heat supply path in the third stage of the temperature rise of the adsorbent 12. FIG. 6 is a graph for explaining the heat transfer between the first module 11A and the second module 11B during the temperature rise of the adsorbent 12. In FIGS. 3 to 6, the illustration of the remaining modules 11 is omitted.

[0044] In the following description, among the plurality of modules 11, the first module 11A and the second module 11B connected by the bypass path 31 will be described as an example. Note that for the common configuration that does not distinguish between the first module 11A and the second module 11B, the alphabet may be omitted and denoted as the module 11.

[0045] First, the structure for supplying the heat medium to the first module 11A and the second module 11B will be described. As shown in FIGS. 3 to 5, each of the first module 11A and the second module 11B includes an inlet-side flow path 33 connected to an inlet through which the heat medium flows, and an outlet-side flow path 34 connected to an outlet through which the heat medium flows out.

[0046] The bypass path 31 is connected to the outlet-side flow path 34 of the first module 11A and is also connected to the inlet-side flow path 33 of the second module 11B. Further, a three-way valve 30 is disposed at the upstream end of the inlet-side flow path 33, and a three-way valve 30 is also disposed at the downstream end of the outlet-side flow path 34.

[0047] The three-way valve 30 disposed at the upstream end of the inlet-side flow path 33 of the first module 11A is referred to as an inlet three-way valve 30a, and the three-way valve 30 disposed at the downstream end of the outlet-side flow path 34 is referred to as an outlet three-way valve 30b. Also, the three-way valve 30 disposed at the upstream end of the inlet-side flow path 33 of the second module 11B is referred to as an inlet three-way valve 30c, and the three-way valve 30 disposed at the downstream end of the outlet-side flow path 34 is referred to as an outlet three-way valve 30d.

[0048] The first stage of the temperature increase control will be described. As shown in FIG. 3, in the first module 11A of the first stage, a desorption process is executed. In the first stage, the control device 90 controls the inlet three-way valve 30a to connect the hot water line 112 and the inlet side flow path 33, and controls the outlet three-way valve 30b to connect the outlet side flow path 34 and the hot water line 112. Further, the control device 90 controls the bypass valve 32 disposed in the bypass path 31 to be in a closed state, thereby blocking the outlet side flow path 34 of the first module 11A and the inlet side flow path 33 of the second module 11B.

[0049] As shown in FIG. 6, in the desorption process, the heat medium in the hot water line 112 is introduced into the first module 11A, and the temperature of the adsorbent 12 in the first module 11A has reached 80°C. The flow rate of the heat medium through the hot water line 112 to the first module 11A is throttled so that the temperature of the adsorbent 12 is maintained at 80°C. Note that the temperature of the adsorbent 12 in the second module 11B is at room temperature of 30°C or lower.

[0050] In the second module 11B of the first stage, the control device 90 controls the inlet three-way valve 30c and the outlet three-way valve 30d to block the second module 11B from both the cold water line 111 and the hot water line 112. In this state, the control device 90 controls the first valve 21, the third valve 23, and the fourth valve 24 of the module 11 to be in a closed state and controls the second valve 22 to be in an open state to drive the vacuum pump 62. Thereby, an operation of purging O2 inside the second module 11B by suction of the vacuum pump 62 is executed for the second module 11B.

[0051] The second stage of the temperature increase control will be described. As shown in Fig. 4, in the first module 11A of the second stage, the desorption process is completed and precooling is started. In the second stage, the control device 90 controls the inlet three-way valve 30a to connect the cold water line 111 and the inlet side flow path 33, and controls the outlet three-way valve 30b to cut off the first module 11A from both the cold water line 111 and the hot water line 112. Further, the control device 90 connects the outlet side flow path 34 of the first module 11A and the inlet side flow path 33 of the second module 11B by controlling the bypass valve 32 to the open state.

[0052] As shown in Fig. 6, the heat medium in the cold water line 111 is introduced into the first module 11A, and the temperature of the adsorbent 12 in the first module 11A is gradually cooled from 80°C to 50°C. Since the outlet three-way valve 30b is closed, the heat medium flowing out from the first module 11A to the outlet side flow path 34 is introduced into the inlet side flow path 33 of the second module 11B through the bypass path 31. The heat medium passing through the bypass path 31 is heated by heat transfer because it cools the adsorbent 12 when passing through the first module 11A, and has a higher temperature than before being introduced into the first module 11A.

[0053] In the second module 11B of the second stage, the control device 90 controls the inlet three-way valve 30c to cut off the inlet side flow path 33 of the second module 11B from both the cold water line 111 and the hot water line 112, and controls the outlet three-way valve 30d to connect the outlet side flow path 34 of the second module 11B and the cold water line 111.

[0054] As shown in Fig. 6, the heat medium heated in the first module 11A is introduced into the second module 11B through the bypass path 31 and the inlet side flow path 33, and the temperature of the adsorbent 12 in the second module 11B gradually rises from room temperature to 50°C. In this way, in the second stage, the baton touch of heat from the first module 11A to the second module 11B is performed.

[0055] The third stage of the temperature increase control will be described. As shown in FIG. 5, precooling continues in the first module 11A of the third stage. In the third stage, while the control device 90 maintains the connection between the cold water line 111 and the inlet side flow path 33 by the inlet three-way valve 30a, it controls the outlet three-way valve 30b to connect the outlet side flow path 34 and the cold water line 111. Further, the control device 90 closes the outlet side flow path 34 of the first module 11A and the inlet side flow path 33 of the second module 11B by controlling the bypass valve 32 to the closed state.

[0056] As shown in FIG. 6, the introduction of the heat medium of the cold water line 111 into the first module 11A continues, and the temperature of the adsorbent 12 in the first module 11A is gradually cooled from 50°C to 30°C. The heat medium flowing out from the first module 11A to the outlet side flow path 34 is returned to the cold water line 111 through the outlet three-way valve 30b.

[0057] In the second module 11B of the third stage, the control device 90 controls the inlet three-way valve 30c to connect the inlet side flow path 33 and the hot water line 112, and controls the outlet three-way valve 30d to connect the outlet side flow path 34 and the hot water line 112.

[0058] As shown in FIG. 6, the 80°C heat medium of the hot water line 112 is introduced into the second module 11B, and the temperature of the adsorbent 12 in the second module 11B is gradually increased from 50°C to 80°C.

[0059] Here, referring to FIG. 7, the difference between the carbon dioxide recovery device 1 of the present embodiment and the carbon dioxide recovery device of the prior art will be described. FIG. 7 is a graph for explaining the heat transfer between the first module and the second module during the temperature increase of the adsorbent when there is no bypass path 31 in the prior art.

[0060] As shown in FIG. 7, when the bypass path 31 is omitted in the configurations of FIGS. 3 to 5, heat transfer from the first module 11A to the second module 11B does not occur. Therefore, the temperature increase control is performed independently for the first module 11A and the second module 11B. The heat medium that has received heat from the first module 11A during cooling is returned to the cold water tank 82 via the cold water line 111 without being used in the second module 11B. Thus, the heat received during cooling is also averaged in the cold water tank 82. Therefore, it is necessary to supply warm water to the adsorbent 12 of the second module starting from room temperature. In this regard, according to the configuration of the present embodiment, since the adsorbent 12 of the second module 11B is pre-heated in the second stage, it is only necessary to increase the temperature from 50°C to 80°C in the third stage. Therefore, the supply amount of warm water can be reduced compared to the case where there is no bypass path 31.

[0061] Next, referring to FIG. 8, the switching timing of the supply path of the heat medium in the temperature increase control will be described. FIG. 8 is a flowchart showing an example of the flow of the process of the temperature increase control by the carbon dioxide recovery apparatus of the present embodiment.

[0062] In step S1, the control device 90 determines whether or not the temperature difference ΔT between the adsorbent 12 of the first module 11A and the adsorbent 12 of the second module 11B is equal to or greater than a certain value. In the present embodiment, the control device 90 acquires the measurement information of the temperature sensor 27 of the first module 11A and the measurement information of the temperature sensor 27 of the second module 11B, and calculates the temperature difference. The control device 90 determines whether or not the calculated temperature difference is equal to or greater than a preset temperature difference ΔT.

[0063] When the temperature difference ΔT between the adsorbent 12 of the first module 11A and the adsorbent 12 of the second module 11B is equal to or greater than a certain value, the control device 90 advances the process to step S2 (step S1; Yes). When the temperature difference ΔT between the adsorbent 12 of the first module 11A and the adsorbent 12 of the second module 11B is less than a certain value, the control device 90 advances the process to step S5 (step S1; No).

[0064] Note that the processes of steps S2 to S4 correspond to the second stage shown in FIG. 4, and the processes of steps S5 to S7 correspond to the third stage shown in FIG. 5.

[0065] In step S2, the control device 90 controls the inlet three-way valve 30a of the first module 11A to connect the cold water line 111 and the inlet-side flow path 33, and controls the outlet three-way valve 30b to cut off the first module 11A from both the cold water line 111 and the hot water line 112.

[0066] In step S3, the control device 90 controls the inlet three-way valve 30c to cut off the inlet-side flow path 33 of the second module 11B from both the cold water line 111 and the hot water line 112, and controls the outlet three-way valve 30d to connect the outlet-side flow path 34 of the second module 11B and the cold water line 111.

[0067] In step S4, the control device 90 controls the bypass valve 32 to an open state to connect the outlet-side flow path 34 of the first module 11A and the inlet-side flow path 33 of the second module 11B. After the process of step S4, the process returns to step S1, and the processes after step S1 are executed.

[0068] When the temperature difference is less than ΔT, in step S5, the control device 90 controls the bypass valve 32 to a closed state to cut off the outlet-side flow path 34 of the first module 11A and the inlet-side flow path 33 of the second module 11B.

[0069] In step S6, the control device 90 controls the inlet three-way valve 30a to connect the inlet-side flow path 33 of the first module 11A and the cold water line 111, and controls the outlet three-way valve 30b to connect the outlet-side flow path 34 of the first module 11A and the cold water line 111.

[0070] In step S7, the control device 90 controls the inlet three-way valve 30c to connect the inlet-side flow path 33 of the second module 11B to the hot water line 112, and controls the outlet three-way valve 30d to connect the outlet-side flow path 34 of the second module 11B to the hot water line 112. As a result, the temperature increase control of the second module 11B is completed, and the process proceeds to the detachment step.

[0071] Note that, for the sake of convenience of explanation, the flowchart of FIG. 8 separately explains step S2, step S3, and step S4, but step S2, step S3, and step S4 may be performed simultaneously. Similarly, step S5, step S6, and step S7 may also be performed simultaneously. Thus, the flowchart of FIG. 8 is an example, and the order and content of the processing can be changed as appropriate.

[0072] The heat transfer described above is performed between the modules 11 connected via the bypass path 31. FIG. 9 is a schematic diagram showing the relationship between the cycle of repeating the adsorption step and the desorption step and the heat transfer between the plurality of modules 11. As shown in FIG. 9, in each module 11, a cycle of desorption, precooling, adsorption, O2 purge, and temperature increase is executed.

[0073] The first module 11A and the second module 11B are connected by a bypass path 31. The second module 11B and the third module 11C are also connected by a different bypass path 31. The third module 11C and the fourth module 11D are also connected by a different bypass path 31. Further, the fourth module 11D and the first module 11A are also connected by a different bypass path 31. In the present embodiment, four modules 11, namely the first module 11A, the second module 11B, the third module 11C, and the fourth module 11D, are set as one set, and a circuit for performing heat baton touch is configured with this one set.

[0074] When the first module 11A proceeds to the temperature increase cycle and the second module 11B proceeds to the precooling cycle, heat moves from the second module 11B during precooling to the first module 11A during temperature increase. When the second module 11B proceeds to the temperature increase cycle and the third module 11C proceeds to the precooling cycle, heat moves from the third module 11C during precooling to the second module 11B during temperature increase. When the third module 11C proceeds to the temperature increase cycle and the fourth module 11D proceeds to the precooling cycle, heat moves from the fourth module 11D during precooling to the third module 11C during temperature increase. When the fourth module 11D proceeds to the temperature increase cycle and the first module 11A proceeds to the precooling cycle, heat moves from the first module 11A during precooling to the fourth module 11D during temperature increase. In the present embodiment, such heat transfer is performed for each of the 16 modules 11.

[0075] FIG. 10 is a schematic diagram showing the numbers assigned to the modules 11 of the carbon dioxide recovery apparatus 1 of the present embodiment. In FIG. 10, numbers are shown as ♯ and numerals to distinguish the modules 11. In the example shown in FIG. 10, the module 11 of #1, the module 11 of #5, the module 11 of #9, and the module 11 of #13 form the first set. The module 11 of #2, the module 11 of #6, the module 11 of #10, and the module 11 of #14 form the second set. The module 11 of #3, the module 11 of #7, the module 11 of #11, and the module 11 of #15 form the third set. The module 11 of #4, the module 11 of #8, the module 11 of #12, and the module 11 of #16 form the fourth set. In each of the first set, the second set, the third set, and the fourth set, four modules 11 are connected in a ring as shown in FIG. 9 by the bypass path 31. Heat transfer between the modules 11 is performed in units of one set.

[0076] Also, in this embodiment, each process for executing the adsorption process and the desorption process is executed with a shift so as not to be performed at the same timing among the plurality of modules 11. Thereby, it is possible to surely avoid the occurrence of a situation where the devices (the fan 61, the heat exchanger 80, the vacuum pump 62, and the carbon dioxide recovery pump 63) operate simultaneously and the output instantaneously increases. Further, the time calculated by dividing the sum of the adsorption time and the desorption time by the number M of the modules 11 is set as the time difference in the operation timing among the modules 11. Thereby, the operation time and output of each device during the operation time can be made more uniform, the operations for realizing each process of the adsorption process and the desorption process can be made more constant, and the energy efficiency can be improved. Furthermore, from the viewpoint of equalizing the load, the number of the modules 11 is preferably 10 or more.

[0077] <Number of modules and setting method for one set> In this embodiment, the number of the modules 11 constituting one set is set so as to correspond to the following mathematical formula (1). In the mathematical formula (1), M represents the number of the modules 11 constituting one set, N represents a natural number, and R represents the ratio of the adsorption time to the desorption time (adsorption time / desorption time). M = N×(R + 1) ··· Mathematical formula (1)

[0078] Here, assume that the adsorption time:desorption time = 3:1. In this case, R, which is the ratio of the adsorption time to the desorption time (adsorption time / desorption time), is 3. Therefore, the appropriate number of the modules 11 is 4 (N = 1), 8 (N = 2), 12 (N = 3), 16 (N = 4), and so on. The number of the modules constituting the set to which the bypass path 31 is connected is set based on the appropriate number of the modules 11 based on the mathematical formula (1). When R is 3, the modules 11 are set to 4 in one set. When the total number of the modules 11 is 8, it is 2 sets, and when the total number of the modules 11 is 12, it is 3 sets. When the total number of the modules 11 is 16, it is 4 sets as in the above embodiment.

[0079] According to Equation (1), M may be a numerical value with a decimal part, but the value of N is set so that the actual number of modules is a natural number. For example, when R = 2.5, the natural numbers are even numbers such as 2, 4, 6 ···, and the appropriate number of modules 11 is 7 (N = 2), 14 (N = 4), 21 (N = 6). Also, when R = 3.5, the natural numbers are even numbers such as 2, 4, 6 ···, and the appropriate number of modules 11 is 9 (N = 2), 18 (N = 4), 27 (N = 6). That is, N is set so that the number of modules 11 is a natural number. Thus, there are multiple optimal numbers of modules 11 selected by R, which is the ratio of adsorption / desorption time.

[0080] Figure 11 is a graph showing heat transfer between 16 modules of the present embodiment. Figure 11 shows heat transfer during the adsorption process and the desorption process for each module number of module 11. The vertical axis is the ratio of heat transfer. As shown in Figure 11, when the number of modules 11 is set based on Equation (1) and the number of modules 11 in one set is set to the minimum appropriate number of modules 11 based on Equation (1), it becomes possible to minimize the total heat energy required for the carbon dioxide recovery device 1.

[0081] As described above, the carbon dioxide recovery device 1 of the present embodiment includes a plurality of modules 11 that execute an adsorption process of sucking a gas containing carbon dioxide into the adsorbent 12 to adsorb carbon dioxide and a desorption process of desorbing carbon dioxide from the adsorbent 12 by heating the adsorbent 12 in a state where the periphery of the adsorbent 12 is depressurized, a heat exchange device 80 that supplies heat for heating the adsorbent 12 through a heat medium to each of the plurality of modules 11, and a bypass path 31 that connects a first module 11A, which is one of the plurality of modules 11, and a second module 11B different from the first module 11A and through which the heat medium can flow.

[0082] As a result, waste heat recovery can be performed between the first module 11A and the second module 11B. Efficient transfer of thermal energy between the first module 11A and the second module 11B becomes possible, and the electrical energy required to heat a heat medium such as hot water can be reduced.

[0083] Also, in the present embodiment, the heat medium that has cooled the first module 11A after the desorption step is supplied to the second module 11B that is heated up in the desorption step through the bypass path 31, whereby heat is supplied from the first module 11A to the second module 11B. As a result, the heat received by the heat medium during cooling of the first module 11A can be directly transferred to the second module 11B without passing through the cold water line 111, and the energy efficiency can be further improved.

[0084] Further, the carbon dioxide recovery device 1 of the present embodiment is disposed between the heat exchanger 80 and the module 11, and further includes a hot water tank 83 that stores hot water as a heat medium. Thereby, the adsorbent 12 to be heated can be efficiently and reliably heated by two heat supplies, namely, the heat supply from the first module 11A to the second module 11B through the bypass path 31 and the heat supply by the hot water from the hot water tank 83.

[0085] Also, in the present embodiment, after heating the adsorbent 12 by supplying heat from the first module 11A to the second module 11B via the bypass path 31, the adsorbent 12 is heated by supplying heat from the hot water tank 83 to the second module 11B in two-stage heating. As a result, since the second module 11B can be preheated using the heat of the first module 11A in advance, the amount of hot water required to raise the temperature of the adsorbent 12 in the second module 11B to a predetermined temperature (for example, 80°C) can be reduced, and the energy cost can be further reduced.

[0086] In this embodiment, when the temperature difference between the adsorbent 12 of the first module 11A during cooling after the desorption process and the adsorbent 12 of the second module 11B whose temperature is to be raised in the desorption process is equal to or greater than a certain value, heat is supplied from the first module 11A to the second module 11B via the bypass path 31. When the temperature difference between the adsorbent 12 of the first module 11A during cooling and the adsorbent 12 of the second module 11B whose temperature is to be raised becomes less than a certain value, the bypass path 31 is closed and heat supply from the hot water tank 83 is started. By the way, if the temperature difference between the first module 11A and the second module 11B disappears, heat transfer from the first module 11A to the second module 11B will not substantially occur. Therefore, it is preferable to quickly switch to heat supply from the hot water tank 83. In this regard, according to the configuration of this embodiment, the switching from heat supply from the first module 11A to the second module 11B to heat supply from the hot water tank 83 is automatically performed at an appropriate timing. It is possible to avoid the occurrence of a situation where the timing of switching to heat supply from the hot water tank 83 is delayed and the time until the desorption process is completed becomes long, and more efficient carbon dioxide recovery can be realized.

[0087] Further, in this embodiment, the carbon dioxide recovery device 1 further includes a fan 61 that supplies gas to the inside of the module 11, a heat exchanger 80 as a heat source that supplies heat for heating the adsorbent 12 of the module 11, a vacuum pump 62 that sucks the gas inside the module 11, and a carbon dioxide recovery pump 63. At least one of the fan 61, the heat exchanger 80, the vacuum pump 62, and the carbon dioxide recovery pump 63 is shared by a plurality of modules 11 and is connected in series by the bypass path 31. The number M of modules 11 is set based on the following mathematical formula (1), where N is a natural number and R is the ratio of the adsorption time of the adsorbent 12 to the desorption time. M = N × (R + 1) ··· Mathematical formula (1)

[0088] Accordingly, by setting the number of modules 11 corresponding to the respective time ratios of adsorption and desorption of the adsorbent 12 and the operation schedule of each module 11, the operations of the adsorption process and the desorption process in each module 11 become continuous, and energy consumption can be suppressed. Since energy consumption can be suppressed, devices with smaller output and capacity (fan 61, heat exchanger 80, vacuum pump 62, and carbon dioxide recovery pump 63) can be selected, and operating costs and manufacturing costs can be reduced.

[0089] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments and modifications. Also, the effects described in the above embodiments are merely a list of preferable effects, and are not limited to those described in the above embodiments.

Explanation of Reference Numerals

[0090] 1 Carbon dioxide recovery device 11 Module 11A First module 11B Second module 12 Adsorbent 30 Three-way valve 31 Bypass path 32 Bypass valve 61 Fan 62 Vacuum pump 63 Carbon dioxide recovery pump 80 Heat exchanger 81 Heat exchanger 82 Cold water tank 83 Hot water tank

Claims

1. A plurality of modules that perform an adsorption step of having an adsorbent inside and sucking a gas containing carbon dioxide into the adsorbent to adsorb the carbon dioxide, and a desorption step of desorbing the carbon dioxide from the adsorbent by heating the adsorbent in a reduced-pressure state; A heat exchanger that supplies heat for heating the adsorbent to each of the plurality of modules via a heat medium; A bypass path that connects a first module, which is one of the plurality of modules, and a second module different from the first module and through which the heat medium can flow; A carbon dioxide recovery device comprising the same.

2. The heat medium that has cooled the first module after the desorption step is supplied to the second module that is heated up in the desorption step through the bypass path, thereby supplying heat from the first module to the second module. The carbon dioxide recovery device according to Claim 1.

3. Further comprising a hot water tank that is disposed between the heat exchanger and the module and stores hot water as the heat medium. The carbon dioxide recovery device according to Claim 1 or 2.

4. After heating the adsorbent by supplying heat from the first module to the second module via the bypass path, the temperature of the adsorbent is increased by two-stage heating in which heat is supplied from the hot water tank to the second module to heat the adsorbent. The carbon dioxide recovery device according to Claim 3.

5. When the temperature difference between the adsorbent of the first module during cooling after the desorption step and the adsorbent of the second module to be heated up in the desorption step is equal to or greater than a certain value, heat is supplied from the first module to the second module via the bypass path. When the temperature difference between the adsorbent of the first module during cooling and the adsorbent of the second module to be heated up becomes less than a certain value, the bypass path is closed and heat supply from the hot water tank is started. The carbon dioxide recovery device according to Claim 4.

6. A fan that supplies gas to the inside of the module; A heat source that supplies heat for heating the adsorbent of the module; A vacuum pump that sucks gas inside the module; Further comprising the same, At least one of the fan, the heat source, and the vacuum pump is shared by the plurality of modules. The number M of the modules connected in series by the bypass path is expressed as follows, where N is a natural number and R is a ratio obtained by dividing the adsorption time of the adsorbent by the desorption time: It is set based on the following formula (1): The carbon dioxide recovery device according to claim 1 or 2. M = N × (R + 1) Formula (1)

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