Carbon dioxide capture equipment

Abstract

To provide a carbon dioxide recovery device which can accurately raise temperature and perform cooling in a desorption process or an adsorption process through proper flow rate of heat medium and achieve energy saving.SOLUTION: A carbon dioxide recovery device 1 comprises: a bypass line 31 which can introduce heat medium passing through a first module 11a into a second module 11b that is different from the first module 11a; and a control unit 90 which is arranged in each of modules 11 and switches a route of heat medium supplied to the module 11 among a hot water line 112, a cold water line 111, and the bypass line 31 to control an upstream side four-way valve 30a and a downstream side four-way valve 30b that are able to adjust flow rate of the heat medium passing through the module 11 so as to change a changeover control where the route of the heat medium is switched and a flow control where the flow rate of the heat medium is adjusted according to a state of an adsorbent 12.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide capture device. [Background technology]

[0002] Conventionally, techniques for recovering carbon dioxide from carbon dioxide-containing gases such as the atmosphere have been known. This type of technique is described, for example, in Patent Document 1. Patent Document 1 describes a method for 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] Special Publication No. 2017-528318 Summary of the Invention [Problem to be solved by the invention]

[0004] In a carbon dioxide capture system that uses multiple modules each having an adsorbent to simultaneously perform a desorption process and an adsorption process, the adsorbent in the first module may be cooled by a cooling heat medium, while the adsorbent in the second module may be heated by a heating heat medium. To improve energy efficiency, it may be possible to recover exhaust heat from the first module and use the recovered heat to heat the adsorbent in the second module.

[0005] In some cases, exhaust heat recovery from the first module alone is not sufficient to heat the adsorbent in the second module to a temperature at which desorption is possible. While it is possible to switch the heat transfer medium used depending on the heating stage, the necessary and sufficient flow rate of the heat transfer medium flowing through the module varies depending on the temperature potential of the heat transfer medium used and the stages of the desorption and adsorption processes. Therefore, if the heat transfer medium is circulated at a constant flow rate without considering the temperature potential of the heat transfer medium supplied to the module or the condition of the adsorbent, there is a risk of excessive heating or cooling of the adsorbent. Furthermore, because the flow rate is directly related to the workload of the pump, it is preferable to set the flow rate of the heat transfer medium to the minimum necessary. Energy conservation in carbon dioxide capture systems is desired, and conventional technologies have had issues with reducing the power consumption of the pump used to circulate the heat transfer medium.

[0006] An object of the present invention is to provide a carbon dioxide recovery device that can accurately raise and lower the temperature in the desorption step and adsorption step using a heat medium at an appropriate flow rate, and that can also achieve energy savings. [Means for solving the problem]

[0007] (1) The present invention relates to a system including a plurality of modules (e.g., module 11 described later) that have an adsorbent (e.g., adsorbent 12 described later) therein and perform an adsorption process of drawing a gas containing carbon dioxide into the adsorbent to adsorb the carbon dioxide, and a desorption process of heating the adsorbent in a state where the atmosphere around the adsorbent is reduced in pressure to desorb the carbon dioxide from the adsorbent; a heating heat medium line (e.g., hot water line 112 described later) for supplying a relatively high-temperature heat medium (e.g., hot water described later) to each of the plurality of modules in order to heat the adsorbent that performs the desorption process; a cooling heat medium line (e.g., cold water line 111 described later) for supplying a relatively low-temperature heat medium (e.g., cold water described later) to cool the adsorbent that performs the adsorption process; and a heat source ( a heat source device 81 described later, a bypass line (e.g., bypass line 31 described later) that can introduce the heat medium that has passed through a first module that is one of the plurality of modules into a second module that is different from the first module; flow control devices (e.g., upstream four-way valve 30a and downstream four-way valve 30b described later) that are arranged in each of the modules and that can switch the path of the heat medium to be supplied to the module from among the heating heat medium line, the cooling heat medium line, or the bypass line, and adjust the flow rate of the heat medium passing through the module; and a control device (e.g., control device 90 described later) that controls the flow control devices to change the switching control for switching the path of the heat medium and the flow control for adjusting the flow rate of the heat medium according to the condition of the adsorbent.

[0008] (2) In the carbon dioxide recovery system described in (1) above, the flow control device is configured by an upstream four-way valve (for example, upstream four-way valve 30a described later) that is connected to the upstream side of the module and to which the heating heat medium line, the cooling heat medium line, and the bypass line are connected, and a downstream four-way valve (for example, downstream four-way valve 30b described later) that is connected to the downstream side of the module and to which the heating heat medium line, the cooling heat medium line, and the bypass line are connected, and the control device may switch the path of the heat medium supplied to the module by switching the internal flow paths of the upstream four-way valve and the downstream four-way valve.

[0009] (3) In the carbon dioxide recovery apparatus described in (1) or (2) above, the control device may control the flow rate so that the flow rate in a holding step, in which the temperature of the adsorbent, which has reached the predetermined temperature by the heating, is maintained at the predetermined temperature, is smaller than the flow rate in a heating step, in which the heat medium supplied from the heating heat medium line heats the adsorbent to the predetermined temperature of the desorption step.

[0010] (4) In the carbon dioxide recovery device described in (1) or (2) above, after the desorption step, the control device may cool the adsorbent of the first module using the heat medium supplied from the cooling heat medium line, and may perform bypass control to raise the temperature of the second module by supplying the heat medium that has cooled the first module to the second module through the bypass line.

[0011] (5) In the carbon dioxide recovery device described in (4) above, after the bypass control, the control device may perform control to increase the flow rate of the heat medium supplied from the cooling heat medium line to the first module compared to the flow rate in the bypass control.

[0012] (6) In the carbon dioxide recovery system described in (4) above, after the bypass control, the control device may close a path from the bypass line to the second module and supply the heat medium from the heating heat medium line to the second module at a flow rate greater than the flow rate of the heat medium supplied during the bypass control. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a carbon dioxide recovery device that can accurately raise and lower the temperature in the desorption step and adsorption step with a heat medium at an appropriate flow rate and that can achieve energy savings. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a schematic diagram showing a configuration relating to gas flow in a carbon dioxide capture device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of gas flow in the module of the carbon dioxide capture device of the present embodiment. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of a heat exchanger of the carbon dioxide recovery device of the present embodiment. [Figure 4] 4 is a graph showing the relationship between the temperature of the adsorbent in the first module and the amount of heat medium supplied. [Figure 5] 10 is a graph showing the relationship between the temperature of the adsorbent in the second module and the amount of heat medium supplied. [Figure 6] FIG. 2 is a schematic diagram illustrating the connection state of the flow channels of the first module and the second module in the first stage. [Figure 7] FIG. 10 is a schematic diagram illustrating the connection state of the flow channels of the first module and the second module in the second stage. [Figure 8] FIG. 10 is a schematic diagram illustrating the connection state of the flow channels of the first module and the second module in the third stage. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] <Gas flow configuration> First, a configuration for recovering carbon dioxide from the atmosphere will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing a configuration related to gas flow in a carbon dioxide recovery device 1 according to one embodiment of the present invention. Figure 2 is a schematic diagram showing a configuration related to gas flow in a module 11 of the carbon dioxide recovery device 1 of this embodiment.

[0017] The carbon dioxide capture device 1 of this embodiment is applied to, for example, direct air capture (DAC) technology that 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.

[0018] 1, the carbon dioxide capture system 1 of this embodiment includes a module unit 10, a fan 61, a vacuum pump 62, a carbon dioxide capture pump 63, an intercooler 64, a separator 65, a carbon dioxide tank 66, and an inert gas tank 69. The carbon dioxide capture system 1 also includes, as gas flow paths, an adsorption line 101, a vacuum line 102, a carbon dioxide line 103, a circulation line 104, and an inert gas supply line 107. Note that a heat exchanger 70 that supplies heat to and recovers exhaust heat from each module 11 is not shown in FIGS. 1 and 2.

[0019] The module unit 10 is configured by arranging a plurality of carbon dioxide adsorbing modules 11 in parallel. In this embodiment, a total of 16 modules 11 are arranged by a pair of left and right module units 10.

[0020] As shown in FIG. 2, module 11 is a carbon dioxide capture module including an adsorbent 12, a first valve 21, a second valve 22, a third valve 23, a fourth valve 24, a pressure sensor 25, a carbon dioxide sensor 26, and a temperature sensor 27.

[0021] The adsorbent 12 is disposed inside the module 11 to adsorb carbon dioxide. The adsorbent 12 is a particulate material that has the property of adsorbing carbon dioxide at low temperatures (for example, in the range of -30°C to 50°C) and desorbing (releasing) carbon dioxide at high temperatures (for example, in the range of 50°C to 110°C) when the ambient carbon dioxide concentration is low. Examples of such adsorbent 12 include solid amine carbon dioxide adsorbents formed by supporting amines on porous materials such as silica.

[0022] The first valve 21 is an on-off valve arranged at the connection between the module 11 and a carbon dioxide line 103 that captures carbon dioxide. A carbon dioxide capture pump 63 is arranged in the carbon dioxide line 103. The second valve 22 is an on-off valve arranged at the connection between the module 11 and a vacuum line 102 in which a vacuum pump 62 is arranged. The third valve 23 is an on-off valve arranged at the inlet that takes in air and the like into the module 11. The fourth valve 24 is an on-off valve arranged at the connection between the adsorption line 101 and the module 11.

[0023] The first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 are all controlled to open and close by a control device 90. The first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 are each configured by, for example, a normally open butterfly valve.

[0024] The pressure sensor 25 measures the internal pressure of the module 11. The carbon dioxide sensor 26 measures the carbon dioxide concentration inside the module 11. The temperature sensor 27 measures the temperature of the adsorbent 12. Measurement information from the pressure sensor 25, the carbon dioxide sensor 26, and the temperature sensor 27 is sent to the control device 90.

[0025] Returning to FIG. 1 , the adsorption line 101 and the fan 61 will be described. The adsorption line 101 branches off and is connected to each of the modules 11. The fan 61 is located where the branched portions of the adsorption line 101 converge. When driven, the fan 61 generates a gas flow from "intake" to "exhaust" through the adsorption line 101 to the module 11. This supplies atmospheric air into the module 11. A carbon dioxide concentration sensor 611, a humidity sensor 612, and a temperature sensor 613 are located in the gas exhaust portion of the adsorption line 101, and measure the carbon dioxide, humidity, and temperature exhausted from the adsorption line 101. Measurement information from the carbon dioxide concentration sensor 611, the humidity sensor 612, and the temperature sensor 613 is sent to the control device 90.

[0026] The vacuum line 102 is branched and connected to each of the modules 11. The vacuum pump 62 is disposed at the point where the branched portions of the vacuum line 102 converge. When the vacuum pump 62 is driven, it sucks gas from inside the module 11 through the vacuum line 102, bringing the inside of the module 11 into a vacuum state or close to a vacuum state.

[0027] The carbon dioxide line 103 branches off and is connected to each of the modules 11. At the point where the branched portions of the carbon dioxide line 103 converge, a carbon dioxide capture pump 63, an intercooler 64, a separator 65, and a carbon dioxide tank 66 are arranged.

[0028] The carbon dioxide capture pump 63 applies suction force to send the carbon dioxide flowing through the carbon dioxide line 103 to the carbon dioxide tank 66. A one-way valve 631 is arranged upstream of the carbon dioxide capture pump 63 in the carbon dioxide line 103. This prevents gas from flowing back from the intercooler 64 side to the module 11 side.

[0029] The intercooler 64 is an intermediate cooling device that cools the high-temperature gas containing carbon dioxide recovered from the module 11 and separates it into gas and liquid.

[0030] The water separated into gas and liquid in intercooler 64 is recovered in separator 65. Separator 65 is provided with a first valve 651 and a second valve 652. First valve 651 opens and closes a path communicating with the gas phase part of separator 65. Second valve 652 opens and closes a path communicating with the liquid phase part of separator 65.

[0031] The carbon dioxide tank 66 stores the carbon dioxide recovered through the carbon dioxide line 103. A tank valve 661 is arranged on the carbon dioxide line 103 upstream of the carbon dioxide tank 66. The tank valve 661 is controlled to open and close by the control device 90. In addition, various sensors such as a pressure sensor 662, a flow rate sensor 663, a humidity sensor 664, a temperature sensor 665, and a carbon dioxide concentration sensor 666 are arranged on the carbon dioxide line 103 between the tank valve 661 and the carbon dioxide tank 66.

[0032] In addition to the carbon dioxide line 103, a circulation line 104 that returns ballast to the carbon dioxide capture pump 63 is connected to the carbon dioxide tank 66. A flow rate sensor 667 is disposed in the circulation line 104. In addition, the carbon dioxide tank 66 is provided with a pressure release valve 668 that releases pressure when the pressure reaches or exceeds a predetermined value.

[0033] Next, the inert gas tank 69 will be described. The inert gas tank 69 stores N2 as an inert gas supplied from an N2 gas cylinder 691 at a certain pressure or higher (for example, 980 kPa). A gas cylinder valve 692 is arranged between the inert gas tank 69 and the N2 gas cylinder 691. Also, the inert gas tank 69 is arranged with a pressure release valve 693 that releases the pressure when the pressure reaches a predetermined pressure or higher. A pressure sensor 694 is arranged inside the inert gas tank 69. Pressure information measured by the pressure sensor 694 is sent to the control device 90.

[0034] The inert gas tank 69 is connected to the carbon dioxide line 103 via an inert gas supply line 107. An inert gas valve 695 is disposed on the inert gas supply line 107. The inert gas valve 695 is controlled to open and close by the control device 90.

[0035] <Configuration of heat exchanger> Next, the configuration of the heat exchanger 70 will be described with reference to Fig. 3. Fig. 3 is a schematic diagram showing the configuration of the heat exchanger 70 of the carbon dioxide recovery system 1 of this embodiment. Fig. 3 illustrates a first module 11a and a second module 11b among the multiple modules 11 as targets for heat supply and exhaust heat recovery by the heat exchanger 70. In the following description, common configurations that do not distinguish between the first module 11a and the second module 11b may be referred to as module 11 with the alphabet omitted.

[0036] The heat exchanger 70 supplies thermal energy to heat the interior of each module 11 of the module unit 10 to a predetermined temperature when the module 11 performs the desorption process. The heat exchanger 70 also recovers unnecessary thermal energy when the module 11 performs the adsorption process.

[0037] The heat exchange device 70 of this embodiment includes a cold water line 111, a water pump 821 for circulating cold water, a hot water line 112, a water pump 831 for circulating hot water, a heat source device 81, a cold water tank 82, a hot water tank 83, an upstream four-way valve 30a, a downstream four-way valve 30b, and a bypass line 31.

[0038] The chilled water line 111 is a pipe through which low-temperature chilled water flows as a cooling heat medium. The chilled water line 111 is branched and connected to the upstream and downstream sides of each module 11, connecting the chilled water tank 82 to each module 11. Of the chilled water lines 111, the line connected to the upstream side of each module 11 is referred to as a chilled water supply line 111a, and the line connected to the downstream side of each module 11 is referred to as a chilled water return line 111b.

[0039] The chilled water supply line 111a is connected in parallel to the multiple modules 11, and chilled water can be supplied to each module 11 in parallel. The chilled water flowing into the module 11 from the chilled water supply line 111a is a relatively high-pressure heat medium because it has not yet passed through the module 11. The chilled water return line 111b is also connected in parallel to the multiple modules 11, and chilled water can be collected in parallel after cooling is complete for each module 11. The chilled water flowing out from the module 11 to the chilled water return line 111b is a relatively low-pressure heat medium because it has already passed through the module 11.

[0040] The cold water circulation water pump 821 is disposed in the cold water line 111. The cold water circulation water pump 821 is, for example, a cascade pump. The cold water circulation water pump 821 circulates the cold water through the cold water line 111.

[0041] The hot water line 112 is a pipe through which high-temperature hot water flows as a heat medium for heating. The hot water line 112 is branched and connected to the upstream and downstream sides of each module 11, connecting the hot water tank 83 to each module 11. Of the hot water lines 112, the line connected to the upstream side of each module 11 is referred to as a hot water supply line 112a, and the line connected to the downstream side of each module 11 is referred to as a hot water return line 112b.

[0042] The hot water supply line 112a is connected in parallel to the multiple modules 11, and hot water can be supplied to each module 11 in parallel. The hot water flowing into the module 11 from the hot water supply line 112a is a heat medium with a relatively high temperature and pressure because it has not yet passed through the module 11. The hot water return line 112b is also connected in parallel to the multiple modules 11, and hot water after heating can also be collected in parallel for each module 11. The hot water flowing out from the module 11 to the hot water return line 112b is a heat medium with a relatively low pressure because it has already passed through the module 11.

[0043] The hot water circulating water pump 831 is disposed in the hot water line 112. The hot water circulating water pump 831 is, for example, a cascade pump. The hot water circulating water pump 831 circulates the hot water through the hot water line 112.

[0044] The heat source device 81 cools the heat medium introduced from the cold water tank 82 and heats the medium introduced from the hot water tank 83. The heat source device 81 is composed of a heat pump that transfers heat by utilizing the compression and expansion of gas.

[0045] The cold water tank 82 stores the cold water flowing through the cold water line 111. The cold water flowing through the cold water line 111 is stored in the cold water tank 82 and then sent to the heat source device 81. The cold water cooled in the heat source device 81 is returned to the cold water tank 82 and then sent to each module 11 through the cold water line 111.

[0046] The hot water tank 83 stores hot water flowing through the hot water line 112. The hot water flowing through the hot water line 112 is stored in the hot water tank 83 and then sent to the heat source device 81. The heat medium heated in the heat source device 81 is returned to the hot water tank 83 and then sent to each module 11 through the hot water line 112.

[0047] The upstream four-way valve 30a is a flow path switching device located upstream of each module 11. The upstream four-way valve 30a has a flow rate adjustment function that adjusts the flow rate of the fluid passing through it. The upstream four-way valve 30a is connected to a cold water supply line 111a, a hot water supply line 112a, and a bypass line 31.

[0048] The upstream four-way valve 30a in this embodiment has an internal flow path that can be switched between a cold water connection state that connects the cold water supply line 111a to the module 11, a hot water connection state that connects the hot water supply line 112a to the module 11, and a bypass connection state that connects the bypass line 31 to the module 11.

[0049] The downstream four-way valve 30b is a flow path switching device located downstream of each module 11. The downstream four-way valve 30b has a flow rate adjusting function that adjusts the flow rate of the fluid passing through it. The downstream four-way valve 30b is connected to a cold water return line 111b, a hot water return line 112b, and a bypass line 31.

[0050] The downstream four-way valve 30b in this embodiment has an internal flow path that can be switched between a cold water connection state connecting the cold water return line 111b to the module 11, a hot water connection state connecting the hot water return line 112b to the module 11, and a bypass connection state connecting the bypass line 31 to the module 11.

[0051] The bypass line 31 is a flow path that allows the heat medium to move between the modules 11. The bypass line 31 connects two modules 11. The modules 11 connected by the bypass line 31 may be adjacent modules, or may be non-adjacent modules 11 located at a distance. In the example of FIG. 3, one end of the bypass line 31 is connected to the downstream four-way valve 30b of the first module 11a, and the other end is connected to the upstream four-way valve 30a of the second module 11b.

[0052] The bypass line 31 connected to the upstream four-way valve 30a of the first module 11a is connected to the downstream four-way valve 30b of a module 11 (not shown) located on the left side of the drawing. The bypass line 31 connected to the downstream four-way valve 30b of the second module 11b is connected to the upstream four-way valve 30a of a module 11 (not shown) located on the right side of the drawing.

[0053] The flow path switching of the upstream four-way valve 30a and the downstream four-way valve 30b is controlled by the control device 90. When hot water is circulated through the module 11, the upstream four-way valve 30a connects the hot water supply line 112a to the upstream side of the module 11, and the downstream four-way valve 30b connects the hot water return line 112b to the downstream side of the module 11. When cold water is circulated through the module 11, the upstream four-way valve 30a connects the cold water supply line 111a to the upstream side of the module 11, and the downstream four-way valve 30b connects the cold water return line 111b to the downstream side of the module 11.

[0054] In the bypass connection state, the downstream side of the first module 11a and the upstream side of the second module 11b are connected via the bypass line 31 by the downstream four-way valve 30b of the first module 11a and the upstream four-way valve 30a of the second module 11b. This allows the heat medium (hot water or cold water) that has passed through the first module 11a to circulate through the bypass line 31 to the second module 11b.

[0055] Next, the control device 90 will be described. The control device 90 controls the operation of each part of the carbon dioxide capture device 1. The control device 90 controls the operation of devices used for adsorption and desorption of carbon dioxide, such as driving and stopping. The control device 90 selectively controls the timing of supplying a heat medium to each module 11 to heat or cool the modules 11, so that the multiple modules 11 repeatedly adsorb and desorb in time series.

[0056] The control device 90 controls the opening and closing of the first valve 21, second valve 22, third valve 23, and fourth valve 24 provided in each module 11, as well as the opening and closing of the upstream four-way valve 30a and downstream four-way valve 30b. The control device 90 also controls the driving of the fan 61, vacuum pump 62, carbon dioxide capture pump 63, cold water circulation water pump 821, hot water circulation water pump 831, etc.

[0057] The control device 90 is, for example, a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The control device 90 may be configured as a single device or as a plurality of devices. The control device 90 may also be configured using an electric circuit such as a relay.

[0058] <Carbon dioxide capture> Next, the control for capturing carbon dioxide by the control device 90 will be described. The carbon dioxide capture device 1 alternately performs an adsorption process in which the adsorbent 12 in the module 11 adsorbs carbon dioxide in gases such as the air that has been taken in, and a desorption process in which the carbon dioxide adsorbed by the adsorbent 12 is desorbed, and the desorbed carbon dioxide is compressed and stored in a tank (not shown), thereby removing and capturing carbon dioxide from the air. In this embodiment, the adsorption process and the desorption process are performed with a ratio of adsorption process time:desorption process time = 3:1.

[0059] The adsorption process is a process in which carbon dioxide is adsorbed by 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 a gas containing carbon dioxide (e.g., the atmosphere) is drawn in through the third valve 23. The drawn in gas passes through the adsorbent 12 in the module 11. At this time, the temperature inside the module 11 is 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 capture device 1 through the fourth valve 24 and the adsorption line 101.

[0060] 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 is operated to suck air into the inside of the module 11 and reduce the pressure to create a vacuum state or a near-vacuum state. At the same time, the heat exchanger 80 causes a heat medium, which serves as a heat source, to flow through the module 11 to supply thermal energy and raise the temperature of the adsorbent 12 in the module 11. The temperature rise control by this heat exchanger 80 will be described later.

[0061] By controlling the temperature rise of the adsorbent 12, the adsorbent 12 is also heated to a predetermined temperature (e.g., 80°C) sufficient for the desorption step, and the carbon dioxide adsorbed in 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, each step is controlled so that 12 of the 16 modules 11 perform the adsorption step and the remaining 4 perform the desorption step.

[0062] <Switching control and flow control> Next, we will explain the flow path switching control and flow rate control according to each stage (situation) of the adsorption process and desorption process by the control device 90. In the flow rate control by the control device 90, the opening degrees of the upstream four-way valve 30a and the downstream four-way valve 30b are feedback-controlled so as to match the target time-varying profile of the temperature of the adsorbent 12.

[0063] The control device 90 may determine each stage of the adsorbent 12 based on the temperature of the adsorbent 12 obtained from the temperature sensor 27, may determine each stage of the adsorbent 12 based on the detected values ​​of various sensors such as the pressure sensor 25, or may determine each stage of the adsorbent 12 by using the passage of time using a timer or the like.

[0064] FIG. 4 is a graph showing the relationship between the temperature of the adsorbent 12 in the first module 11a and the amount of heat medium supplied. FIG. 5 is a graph showing the relationship between the temperature of the adsorbent 12 in the second module 11b and the amount of heat medium supplied. Note that the stages shown in FIG. 4 correspond to the stages shown in FIG. 5, and the first module 11a and the second module 11b are assumed to perform their respective processes in parallel. The first, second, and third stages indicate the order in the graph. For example, the first stage in FIG. 4 does not represent the initial state of the adsorbent 12 in the carbon dioxide capture device 1, but rather represents the state after the temperature rise control performed chronologically prior to the graph in FIG. 4 and the desorption process.

[0065] First, the first stage control on the first module 11a side shown in Fig. 4 will be described. In the first stage on the first module 11a side, a desorption process is performed. In this desorption process, the adsorbent 12 has reached 80°C by the temperature rise control performed in advance.

[0066] 6 is a schematic diagram illustrating the connection state of the flow paths of the first module 11a and the second module 11b in the first stage. As shown in FIG. 6, in the first stage, the upstream four-way valve 30a and the downstream four-way valve 30b are controlled to a hot water connection state. This connects the hot water supply line 112a to the upstream side of the first module 11a, and also connects the downstream side of the first module 11a to the hot water return line 112b.

[0067] 4, the temperature of the adsorbent 12 has already reached 80°C, so the amount of hot water supplied may be any amount that can maintain the temperature of the adsorbent 12. Therefore, the control device 90 in the first stage controls the openings of the upstream four-way valve 30a and the downstream four-way valve 30b of the first module 11a to reduce the flow rate (e.g., 5 L / min) relatively lower than the flow rate (e.g., 10 L / min) in the previous temperature-raising stage shown in the graph of FIG.

[0068] 5, an operation of purging O2 from the inside of the second module 11b is performed by suction from the vacuum pump 62. The temperature of the adsorbent 12 in the second module 11b is, for example, room temperature of 30°C or less. While O2 is being purged, the control device 90 controls the upstream four-way valve 30a and the downstream four-way valve 30b to close all of the paths of the second module 11b, including the cold water line 111, the hot water line 112, and the bypass line 31, and controls the second module 11b to a state in which the heat medium does not flow.

[0069] Next, the second stage will be described. As shown in Figure 4, the desorption process is completed in the first module 11a of the second stage, and pre-cooling (series) begins. The series here means that the cold water passes through the first module 11a and then the second module 11b.

[0070] 7 is a schematic diagram illustrating the connection state of the flow paths of the first module 11a and the second module 11b in the second stage. As shown in FIG. 7, the control device 90 controls the upstream four-way valve 30a to the chilled water connection state and the downstream four-way valve 30b to the bypass connection state. This connects the chilled water supply line 111a to the upstream side of the first module 11a, and also connects the downstream side of the first module 11a to the bypass line 31.

[0071] 5, in the second module 11b of the second stage, the O2 purge is completed and the first temperature rise control is initiated. The first temperature rise control is performed to raise the temperature of the adsorbent 12 from room temperature to around 50°C.

[0072] 7, the second-stage control device 90 controls the upstream four-way valve 30a to the bypass connection state and the downstream four-way valve 30b to the chilled water connection state, thereby connecting the bypass line 31 to the upstream side of the second module 11b and connecting the downstream side of the second module 11b to the chilled water return line 111b.

[0073] In the first module 11a of the second stage, cold water from the cold water supply line 111a is introduced into the upstream side of 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. The cold water flowing out from the downstream side of the first module 11a receives heat from the adsorbent 12 while passing through the first module 11a, and has a higher temperature than before it was introduced into the first module 11a.

[0074] Meanwhile, in the second module 11b in the second stage, the water (bypass water) that has passed through the first module 11a is introduced to the upstream side of the second module 11b through the bypass line 31. The bypass water gradually increases the temperature of the adsorbent 12 in the second module 11b from room temperature to around 50°C. In this way, in the second stage, heat is passed from the first module 11a to the second module 11b.

[0075] The second stage of pre-cooling the first module 11a and heating the second module 11b is an intermediate stage toward the final target temperature, and the required flow rate is relatively small. Therefore, in the second stage, the control device 90 reduces the opening of the upstream four-way valve 30a and the downstream four-way valve 30b of the first module 11a and the upstream four-way valve 30a and the downstream four-way valve 30b of the second module 11b, thereby controlling the flow rate to be relatively small (for example, 5 L / min).

[0076] Next, the third stage will be described. As shown in Fig. 4, pre-cooling (parallel) is performed in the first module 11a in the third stage. "Parallel" here means that heat transfer media (cold water and hot water) are supplied in parallel to the first module 11a and the second module 11b, respectively.

[0077] FIG. 8 is a schematic diagram illustrating the connection state of the flow paths of the first module 11a and the second module 11b in the third stage. As shown in FIG. 8, the control device 90 in the third stage controls the upstream four-way valve 30a and the downstream four-way valve 30b of the first module 11a to a cold water connection state. This connects the cold water supply line 111a to the upstream side of the first module 11a, and also connects the downstream side of the first module 11a to the cold water return line 111b. Low-temperature cold water from the cold water supply line 111a is introduced into the first module 11a, and the temperature of the adsorbent 12 in the first module 11a is cooled from 50°C to around 30°C.

[0078] The pre-cooling (parallel) of the first module 11a in the third stage is a process of cooling the temperature of the adsorbent 12 of the first module 11a from 50°C to the target temperature (30°C), and the control device 90 controls the opening degree of the upstream four-way valve 30a and the downstream four-way valve 30b of the first module 11a so that the flow rate is higher (e.g., 10 l / min) than in the pre-cooling (series) of the second stage.

[0079] 5, in the second module 11b in the third stage, the first temperature rise control is completed and the second temperature rise control is initiated. The second temperature rise control is performed to raise the temperature of the adsorbent 12 from around 50°C to 80°C, which is the target temperature for the desorption step.

[0080] As shown in Fig. 8, the third-stage control device 90 controls the upstream four-way valve 30a and downstream four-way valve 30b of the second module 11b to a hot water connection state. This connects the hot water supply line 112a to the upstream side of the second module 11b, and also connects the downstream side of the second module 11b to the hot water return line 112b. The high-temperature hot water in the hot water supply line 112a is introduced into the second module 11b, and the temperature of the adsorbent 12 in the second module 11b gradually increases from 50°C to 80°C.

[0081] The second temperature rise control of the second module 11b in the third stage is a process of raising the temperature of the adsorbent 12 of the second module 11b from 50°C to the target temperature (80°C), and the control device 90 controls the opening degree of the upstream four-way valve 30a and the downstream four-way valve 30b of the second module 11b so that the flow rate is higher (e.g., 10 l / min) than in the first temperature rise control of the second stage.

[0082] As described above, the carbon dioxide capture device 1 of this embodiment includes a plurality of modules 11 that have adsorbents 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 reduced pressure to desorb carbon dioxide from the adsorbent 12, a hot water line (heating heat medium line) 112 for supplying relatively high-temperature hot water (heat medium) to heat the adsorbent 12 that is undergoing the desorption process to each of the plurality of modules 11, a cold water line (cooling heat medium line) 111 for supplying a relatively low-temperature heat medium (cold water) to cool the adsorbent 12 that is undergoing the adsorption process, and a cold water line (cooling heat medium line) 111 for heating the hot water flowing in the hot water line 112 and cooling the cold water flowing in the cold water line 111. the heat medium that has passed through a first module 11a, which is one of the plurality of modules 11, to a second module 11b that is different from the first module 11a; an upstream four-way valve 30a and a downstream four-way valve 30b (flow rate control devices) that are arranged in each of the modules 11 and that can switch the path of the heat medium to be supplied to the module 11 from among the hot water line 112, the cold water line 111, or the bypass line 31, and adjust the flow rate of the heat medium passing through the module 11; and a control device 90 that controls the upstream four-way valve 30a and the downstream four-way valve 30b to change the switching control for switching the path of the heat medium and the flow rate control for adjusting the flow rate of the heat medium according to the condition of the adsorbent 12.

[0083] This allows for waste heat recovery between the first module 11a and the second module 11b. Efficient thermal energy transfer between the first module 11a and the second module 11b is possible, reducing the amount of electrical energy required to heat a heat medium such as hot water. Furthermore, the flow rate can be changed at each stage of the adsorption and desorption processes. By selecting an appropriate flow rate depending on the state of the adsorbent 12, the required amount of water can be supplied without excess or deficiency. Furthermore, pressure loss (required head) is proportional to the square of the flow rate, and the workload of the cold water circulation water pump 821 and the hot water circulation water pump 831 is proportional to the product of the head and the flow rate. Without valve opening adjustment, the hot water or cold water heat medium always flows at the maximum flow rate. However, in this embodiment, the flow rate can be reduced depending on the stage, significantly reducing the pump workload and improving the energy efficiency of the carbon dioxide capture device 1.

[0084] In addition, in this embodiment, the flow control device is composed of an upstream four-way valve 30a that is connected to the upstream side of the module 11 and to which the hot water line 112, the cold water line 111, and the bypass line 31 are connected, and a downstream four-way valve 30b that is connected to the downstream side of the module 11 and to which the hot water line 112, the cold water line 111, and the bypass line 31 are connected, and the control device 90 switches the path of the heat medium supplied to the module 11 by switching the internal flow paths of the upstream four-way valve 30a and the downstream four-way valve 30b.

[0085] This allows the upstream four-way valve 30a and the downstream four-way valve 30b to perform switching control of the heat medium supplied through the hot water line 112, the cold water line 111, and the bypass line 31. There is no need to provide a flow rate adjustment function for each of the hot water line 112, the cold water line 111, and the bypass line 31, so a simple configuration can be realized for changing the flow rate of the heat medium supplied to the adsorbent 12 in accordance with the temperature potential.

[0086] Furthermore, in this embodiment, the control device 90 controls the flow rate so that the flow rate in the temperature-raising stage, in which the adsorbent 12 is heated to a predetermined temperature by hot water supplied from the hot water line 112, is smaller than the flow rate in the temperature-holding stage, in which the temperature of the adsorbent 12, which has reached a predetermined temperature by heating, is maintained at the predetermined temperature.

[0087] This allows the flow rate of the heat transfer medium supplied to the module 11 to be lower during the desorption process, which requires a lower flow rate for the purpose of maintaining temperature, than during the temperature increase stage, thereby reducing the workload of the hot water circulation water pump 831.

[0088] Furthermore, in this embodiment, after the desorption process, the control device 90 cools the adsorbent 12 in the first module 11a with cold water supplied from the cold water line 111, and also performs bypass control to raise the temperature of the second module 11b by supplying the cold water used to cool the first module 11a to the second module 11b through the bypass line 31.

[0089] This allows the temperature of the adsorbent 12 in the second module 11b to be increased by the cold water having the heat received when cooling the adsorbent 12 in the first module 11a. Since the temperature can be increased by utilizing exhaust heat recovery without adding heat supply from the outside, energy efficiency can be further improved.

[0090] Furthermore, in this embodiment, after the bypass control, the control device 90 performs control to increase the flow rate of the chilled water supplied from the chilled water line 111 to the first module 11a compared to the bypass control.

[0091] As a result, during bypass control, bypass water can be supplied from the first module 11a to the second module 11b at the flow rate required by the second module 11b while suppressing the workload of the cold water circulation water pump 821. Furthermore, since the flow rate of cold water increases after bypass control, the adsorbent 12 in the first module 11a can be quickly heated to a predetermined temperature.

[0092] Furthermore, in this embodiment, after the bypass control, the control device 90 closes the path from the bypass line 31 to the second module 11b, and supplies the heat medium from the hot water line 112 to the second module 11b at a flow rate greater than the flow rate of the heat medium supplied during the bypass control. Furthermore, after the bypass control, hot water at a high temperature and a high flow rate is supplied to the second module 11b, so that the adsorbent 12 in the second module 11b can be quickly cooled to room temperature.

[0093] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. 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]

[0094] 1. Carbon dioxide capture device 11 Modules 11a First Module 11b Second Module 12 Adsorbent 30a Upstream four-way valve 30b Downstream four-way valve 31 Bypass Line 81 Heat source device 90 Control device 111 Cold water line 111a Cold Water Line 111b Cold water recovery line 112 Hot water line 112a Hot water out line 112b Hot water return line

Claims

1. a plurality of modules each having an adsorbent therein, each performing an adsorption step of sucking 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; a heating medium line for supplying a relatively high-temperature heat medium to each of the plurality of modules in order to heat the adsorbent that is subjected to the desorption step; a cooling heat medium line for supplying a relatively low-temperature heat medium to cool the adsorbent that is undergoing the adsorption step; a heat source unit capable of heating the heat medium flowing through the heating heat medium line and cooling the heat medium flowing through the cooling heat medium line; a bypass line capable of introducing the heat medium that has passed through a first module that is one of the plurality of modules into a second module that is different from the first module; a flow rate adjusting device that is disposed in each of the modules and that switches the path of the heat medium to be supplied to the module from among the heating heat medium line, the cooling heat medium line, or the bypass line, and that adjusts the flow rate of the heat medium passing through the module; a control device that controls the flow rate adjustment device to change switching control for switching the path of the heat medium and flow rate control for adjusting the flow rate of the heat medium according to a state of the adsorbent; A carbon dioxide capture device comprising:

2. The flow rate adjusting device is an upstream four-way valve connected to the upstream side of the module and to which the heating heat medium line, the cooling heat medium line, and the bypass line are connected; a downstream four-way valve connected to the downstream side of the module and to which the heating heat medium line, the cooling heat medium line, and the bypass line are connected; It is composed of the control device switches the path of the heat medium supplied to the module by switching internal flow paths of the upstream four-way valve and the downstream four-way valve. The carbon dioxide capture device according to claim 1 .

3. The control device the flow rate control is performed so that the flow rate in a temperature-raising step, in which the heat medium supplied from the heating heat medium line heats the adsorbent to a predetermined temperature for the desorption step, is smaller than the flow rate in a holding step, in which the temperature of the adsorbent, which has reached the predetermined temperature by the heating, is maintained at the predetermined temperature. The carbon dioxide recovery device according to claim 1 or 2.

4. The control device after the desorption step, the adsorbent in the first module is cooled by the heat medium supplied from the cooling heat medium line, and the heat medium used to cool the first module is supplied to the second module through the bypass line, thereby performing bypass control to raise the temperature of the second module. The carbon dioxide recovery device according to claim 1 or 2.

5. The control device After the bypass control, a flow rate of the heat medium supplied from the cooling heat medium line to the first module is controlled to be larger than that of the bypass control. The carbon dioxide recovery device according to claim 4.

6. The control device after the bypass control, a path from the bypass line to the second module is closed, and the heat medium is supplied from the heating heat medium line to the second module at a flow rate greater than the flow rate of the heat medium supplied in the bypass control. The carbon dioxide recovery device according to claim 4.

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