Carbon dioxide recovery device and carbon dioxide recovery method

Abstract

To provide a carbon dioxide recovery device and a carbon dioxide recovery method with high energy efficiency, utilizing cooling of high-temperature gas containing carbon dioxide and superheated steam.SOLUTION: A carbon dioxide recovery device 1 includes: a reactor 11; a heat exchanger 70 that can execute heating of supplying hot water and cooling of supplying cold water to the reactor 11; a first intercooler 51 that cools gas containing carbon dioxide and steam desorbed in a desorption step; and a second intercooler 52 that cools gas containing carbon dioxide and steam desorbed in the desorption step. The heat exchanger 70 includes: a heat pump-type heat source unit 81; a heat source high-temperature water circuit 85 that heats hot water having heated the reactor 11 by the heat source unit 81 and performs exhaust heat recovery from the first intercooler 51 with the hot water; and a heat source low-temperature water circuit 86 that cools cold water having cooled the reactor 11 by the heat source unit 81 and performs exhaust heat recovery from the second intercooler 52 with the cold water.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] Conventionally, carbon dioxide capture devices have been known that capture carbon dioxide by drawing a gas such as air containing carbon dioxide into a reactor that holds an adsorbent, causing the adsorbent to adsorb the gas, and then desorbing the adsorbent by heating it under reduced pressure. Patent Document 1, for example, describes this type of technology. Patent Document 1 describes a CO2 separator for an internal combustion engine that is installed in the exhaust system of the internal combustion engine and separates CO2 from exhaust gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-152387 Summary of the Invention [Problem to be solved by the invention]

[0004] In the desorption process of a carbon dioxide capture device, high-temperature gas containing carbon dioxide and superheated steam is cooled by a cooling device such as an intercooler to separate the gas and liquid. Because high-temperature superheated steam contains a large amount of thermal energy, a low-temperature heat transfer medium and a configuration for supplying it are required for sufficient cooling. Meanwhile, the reactor holding the adsorbent must be supplied with heat by a heat source such as a heat pump, and the cooling of the superheated steam can be considered an energy loss. Conventional technology leaves room for improvement in terms of improving energy efficiency.

[0005] An object of the present invention is to provide a highly energy-efficient carbon dioxide recovery device and carbon dioxide recovery method that utilizes cooling of high-temperature gas containing carbon dioxide and superheated steam. [Means for solving the problem]

[0006] (1) The present invention provides a reactor (for example, reactor 11 described later) that contains an adsorbent (for example, adsorbent 12 described later) and performs an adsorption process in which a gas containing carbon dioxide is drawn into the adsorbent to adsorb the carbon dioxide, and a desorption process in which the adsorbent is heated under reduced pressure to desorb the carbon dioxide from the adsorbent; a heat exchanger (for example, heat exchanger 70 described later) that can perform heating and cooling by supplying a heat medium for heating (for example, hot water described later) to the reactor; a first cooler (for example, first intercooler 51 described later) that cools the gas containing the carbon dioxide and water vapor desorbed in the desorption process; and a cooling device (for example, first intercooler 52 described later) that can perform cooling by supplying a heat medium for heating (for example, hot water described later) to the reactor and a cooling device (for example, cold water described later) to the reactor. and a second cooling device (for example, a second intercooler 52 described later) that cools a gas containing carbon dioxide, and the heat exchange device is a carbon dioxide recovery device (for example, a carbon dioxide recovery device 1 described later) that has a heat pump type heat source device (for example, a heat source device 81 described later) that heats the heating heat medium and cools the cooling heat medium, a heat source high-temperature water circuit (for example, a heat source high-temperature water circuit 85 described later) that heats the heating heat medium that has heated the reactor by the heat source device and recovers exhaust heat from the first cooling device by the heating heat medium, and a heat source low-temperature water circuit (for example, a heat source low-temperature water circuit 86 described later) that cools the cooling heat medium that has cooled the reactor by the heat source device and recovers exhaust heat from the second cooling device by the cooling heat medium.

[0007] (2) The carbon dioxide recovery device described in (1) above further includes a control device (for example, the control device 90 described below) that controls the flow rate of the heating heat medium flowing to the first cooling machine and the flow rate of the cooling heat medium flowing to the second cooling machine based on the balance between the heating load on the heat source high-temperature water circuit and the amount of exhaust heat recovered in the heat source low-temperature water circuit.

[0008] (3) In the carbon dioxide recovery device described in (2) above, the control device may calculate the amount of carbon dioxide and water recovered based on the environmental conditions of the outside air, calculate the heating load based on the predicted amount of carbon dioxide and water recovered, calculate the amount of exhaust heat recovered in the heat source low-temperature water circuit based on the cooling requirement of the target equipment performing the adsorption process or the desorption process or the cooling requirement of the reactor, predict the heating COP during operation of the heat source device based on the respective temperatures of the heating heat medium and the cooling heat medium supplied to the heat source device and the heating load, and if the heating COP can be improved, select a first heat recovery mode (e.g., a cascade heat recovery mode described later) in which exhaust heat is recovered by each of the first and second coolers, and if the heating COP cannot be improved even when the first heat recovery mode is selected, select a second heat recovery mode (e.g., a low-temperature side heat recovery mode described later) in which exhaust heat is recovered by the second cooler.

[0009] (4) In the carbon dioxide recovery device described in (3) above, in the first heat recovery mode, the amount of heat and temperature recovered in the heat source high-temperature water circuit may be controlled by controlling at least one of the flow rate of the heating heat medium flowing to the first cooling machine and the flow rate of the cooling heat medium flowing to the second cooling machine so as to maximize the heating COP of the heat source device.

[0010] (5) In the carbon dioxide capture device according to any one of (1) to (3) above, the second cooler may cool the gas cooled by the first cooler.

[0011] (6) In the carbon dioxide recovery system described in any one of (1) to (3) above, the heat source high-temperature water circuit includes a heating heat medium tank (for example, a hot water tank 83 described later) for storing the heating heat medium, a heating heat medium side heat source supply line (for example, a hot water side heat source supply line 221 described later) for sending the heating heat medium from the heating heat medium tank to the heat source device, and a heating heat medium side heat source return line (for example, a hot water side heat source return line 222 described later) for returning the heating heat medium from the heat source device to the heating heat medium tank, and the first cooling machine may be disposed in the heating heat medium supply line (for example, a hot water supply line 112a described later) for supplying the heating heat medium from the heating heat medium tank to the reactor or in the heating heat medium side heat source return line (for example, the hot water side heat source return line 222 described later).

[0012] (7) In the carbon dioxide recovery device described in any one of (1) to (3) above, the heat source low-temperature water circuit includes a cooling heat medium tank (chilled water tank 82) for storing the heating heat medium, a cooling heat medium side heat source supply line (for example, a chilled water side heat source supply line 121 described later) for sending the cooling heat medium from the cooling heat medium tank to the heat source device, a cooling heat medium side heat source return line (for example, a chilled water side heat source return line 122 described later) for returning the cooling heat medium from the heat source device to the cooling heat medium tank, and a cooling heat medium side heat source return line (for example, a chilled water side heat source return line 122 described later) for returning the cooling heat medium from the heat source device to the cooling heat medium tank. and an equipment heat recovery circuit (e.g., equipment heat recovery circuit 87 described later) that branches off and is connected to the inlet side of the heat source device of the heat source low-temperature water circuit via a target device for performing the adsorption process or the desorption process, and returns the cooling heat medium that has recovered exhaust heat from the target device to the heat source device, and the second cooling machine may be arranged as the target device in a cooling heat medium return line (e.g., cold water return line 111b described later) that returns the cooling heat medium from the reactor to the cooling heat medium tank or in the equipment heat recovery circuit.

[0013] (8) In the carbon dioxide recovery device described in (7) above, the target equipment may be a pump that applies suction force to the reactor (e.g., a vacuum pump 62 or a carbon dioxide recovery pump 63 described later), and the second cooling machine may be arranged downstream of the pump in the equipment heat recovery circuit.

[0014] (9) The present invention also provides a reactor (for example, reactor 11 described later) having an adsorbent (for example, adsorbent 12 described later) therein, which performs an adsorption step of drawing a gas containing carbon dioxide into the adsorbent to adsorb the carbon dioxide, and a desorption step of heating the adsorbent in a state where the atmosphere around the adsorbent is reduced in pressure to desorb the carbon dioxide from the adsorbent; a heat exchanger (for example, heat exchanger 70 described later) capable of heating and cooling by supplying a heat medium for heating (for example, hot water described later) to the reactor; a first cooler (for example, first intercooler 51 described later) that cools the gas containing carbon dioxide and water vapor desorbed in the desorption step; and a cooling device (for example, first intercooler 52 described later) that cools the gas containing carbon dioxide and water vapor desorbed in the desorption step. and a second cooler (for example, second intercooler 52 described later) that cools the gas containing the carbon dioxide and water vapor desorbed in the process, wherein the heating heat medium is heated and the cooling heat medium is cooled by a heat pump type heat source device (for example, heat source device 81 described later) included in the heat exchange device, the heating heat medium that has heated the reactor is heated by the heat source device, and exhaust heat is recovered from the first cooler by the heating heat medium, and the cooling heat medium that has cooled the reactor is cooled by the heat source device, and exhaust heat is recovered from the second cooler by the cooling heat medium. [Effects of the Invention]

[0015] According to the present invention, in a carbon dioxide recovery device and a carbon dioxide recovery method that perform the desorption process and adsorption process by thermal control of a heat pump-type heat source, a configuration can be provided that allows for quick start-up even when the outside air temperature is low. [Brief explanation of the drawings]

[0016] [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 a configuration relating to the flow of liquid in the carbon dioxide capture device of the present embodiment. [Figure 3] FIG. 2 is a schematic diagram showing a configuration relating to gas flow in a reactor of the carbon dioxide capture device of the present embodiment. [Figure 4] FIG. 2 is a schematic diagram showing a configuration relating to the flow of liquid in a reactor of the carbon dioxide capture device of the present embodiment. [Figure 5] 1 is a schematic diagram showing the configuration of a heat source circuit of a carbon dioxide recovery device according to an embodiment of the present invention. [Figure 6] FIG. 3 is a schematic diagram of a high-temperature gas cooling mechanism using a first intercooler and a second intercooler. [Figure 7] 6 is a graph showing the relationship between the temperature of superheated steam of high-temperature gas and the temperature of hot water, which changes due to cooling by the first intercooler. [Figure 8] 6 is a graph showing the relationship between the temperature of the subcooled liquid and the temperature of the cold water, which change due to cooling by the second intercooler. [Figure 9] 10 is a bar graph showing the respective component ratios of the heating load of the heat source high-temperature water circuit and the exhaust heat recovery of the heat source low-temperature water circuit. [Figure 10] 1 is a graph showing the relationship between the heat exchange amount of a heat source device and heating COP. [Figure 11] 3 is a flowchart showing an example of a process for controlling the operation of the carbon dioxide capture device according to the present embodiment. [Figure 12] FIG. 10 is a schematic diagram of a cooling mechanism for high-temperature gas using a first intercooler and a second intercooler according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] <Overall structure> Fig. 1 is a schematic diagram showing the configuration related to gas flow in a carbon dioxide capture device 1 according to one embodiment of the present invention. Fig. 2 is a schematic diagram showing the configuration related to liquid flow in the carbon dioxide capture device 1 of this embodiment. Note that the configuration related to liquid flow in the carbon dioxide capture device 1 is omitted in Fig. 1, and the configuration related to gas flow in the carbon dioxide capture device 1 is omitted in Fig. 2.

[0019] 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.

[0020] As shown in Figures 1 and 2, the carbon dioxide capture device 1 of this embodiment includes a reactor unit 10, a fan 61, a vacuum pump 62, a carbon dioxide capture pump 63, a first intercooler 51, a second intercooler 52, a separator 65, a carbon dioxide tank 66, an inert gas tank 69, a heat exchanger 70, and a control device 90.

[0021] As shown in FIG. 1, the carbon dioxide recovery device 1 includes an adsorption line 101, a vacuum line 102, a carbon dioxide line 103, a circulation line 104, and an inert gas supply line 107 as gas flow paths.

[0022] The reactor unit 10 is configured by arranging a plurality of reactors 11 in parallel, each of which adsorbs carbon dioxide. In this embodiment, a total of 16 reactors 11 are arranged by a pair of left and right reactor units 10.

[0023] 3 is a schematic diagram showing a configuration related to gas flow in the reactor 11 of the carbon dioxide capture device 1 of this embodiment. The reactor 11 is a carbon dioxide capture reactor 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.

[0024] The adsorbent 12 is placed inside the reactor 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 amine on a porous material such as silica.

[0025] The first valve 21 is an on-off valve arranged at the connection between the reactor 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 reactor 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 reactor 11. The fourth valve 24 is an on-off valve arranged at the connection between the adsorption line 101 and the reactor 11.

[0026] 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.

[0027] The pressure sensor 25 measures the internal pressure of the reactor 11. The carbon dioxide sensor 26 measures the carbon dioxide concentration inside the reactor 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.

[0028] 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 reactors 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 reactor 11. This supplies atmospheric air into the reactor 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.

[0029] The vacuum line 102 is branched and connected to each of the reactors 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 the inside of the reactor 11 through the vacuum line 102, bringing the inside of the reactor 11 into a vacuum state or a state close to a vacuum state.

[0030] The carbon dioxide line 103 branches off and is connected to each of the reactors 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.

[0031] 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 on the carbon dioxide line 103 upstream of the carbon dioxide capture pump 63. This prevents gas from flowing back from the intercooler 64 side to the reactor 11 side.

[0032] The first intercooler 51 and the second intercooler 52 are both intercoolers that cool the high-temperature gas (superheated steam) containing carbon dioxide recovered from the reactor 11 and separate it into gas and liquid. The first intercooler 51 and the second intercooler 52 are arranged in series. The first intercooler 51 cools the high-temperature gas (for example, 120°C), and the superheated steam contained in the high-temperature gas becomes a supercooled liquid (for example, 80°C). The second intercooler 52 further cools the supercooled liquid (for example, 80°C) generated by the cooling of the first intercooler 51, and turns it into a low-temperature supercooled liquid (for example, 32°C).

[0033] The supercooled liquid separated into gas and liquid through the first intercooler 51 and the second intercooler 52 is recovered in a separator 65. A first valve 651 and a second valve 652 are disposed in the separator 65. The first valve 651 opens and closes a path communicating with the gas phase part of the separator 65. The second valve 652 opens and closes a path communicating with the liquid phase part of the separator 65.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The heat exchanger 70 will be described with reference to Fig. 2. The heat exchanger 70 supplies thermal energy for heating the interior of each reactor 11 of the reactor unit 10 to a predetermined temperature when the reactor 11 performs the desorption step. The heat exchanger 70 also recovers unnecessary thermal energy when the reactor 11 performs the adsorption step.

[0039] The heat exchange device 70 of this embodiment includes a heat source circuit 80, a cold water line 111, a hot water line 112, a three-way valve 30, a bypass path 31, and a bypass valve 32.

[0040] The heat source circuit 80 mainly comprises a heat source device 81, a cold water tank 82, and a hot water tank 83, and performs heat exchange between a cooling heat medium flowing in a cold water line 111 and a heating heat medium flowing in a hot water line 112. Due to the heat transfer that occurs in the heat source circuit 80, the heat medium flowing in the cold water line 111 is cooled and the heat medium flowing in the hot water line 112 is heated. The heat medium is, for example, a liquid such as water. The detailed configuration of the heat source circuit 80 will be described later with reference to FIG. 5.

[0041] The cold water line 111 is a pipe through which cold water flows as a cooling heat medium. The cold water line 111 is branched and connected to the upstream and downstream sides of each reactor 11, connecting the cold water tank 82 to each reactor 11. Of the cold water lines 111, the line connected to the upstream side of each reactor 11 is referred to as a cold water supply line 111a, and the line connected to the downstream side of each reactor 11 is referred to as a cold water return line 111b.

[0042] The cold water supply line 111a is connected in parallel to the multiple reactors 11, and cold water can be supplied in parallel to each reactor 11. A first cold water circulation water pump 822 and a second cold water circulation water pump 823 are arranged in the cold water supply line 111a. The first cold water circulation water pump 822 and the second cold water circulation water pump 823 are, for example, cascade pumps.

[0043] Additionally, a circulation line 824 is arranged in the chilled water supply line 111a, returning from the downstream side of the second chilled water circulation water pump 823 to the upstream side. A safety valve 825 is arranged in this circulation line 824. The safety valve 825 relieves pressure when the pressure in the system between the second chilled water circulation water pump 823 and the chilled water line 111 exceeds a certain level, thereby suppressing a pressure increase. By arranging the safety valve 825, which relieves pressure in the event of an abnormality in the chilled water line 111, in parallel with the second chilled water circulation water pump 823, it is possible to achieve both a large flow rate circulation by the second chilled water circulation water pump 823 and safe operation.

[0044] The cold water recovery line 111b is also connected in parallel to the plurality of reactors 11, and the recovery of cold water after cooling can also be carried out in parallel for each reactor 11.

[0045] The hot water line 112 is a pipe through which hot water as a heat medium for heating flows. The hot water line 112 is branched and connected to the upstream and downstream sides of each reactor 11, and connects the hot water tank 83 to each reactor 11. Of the hot water lines 112, the line connected to the upstream side of each reactor 11 is referred to as a hot water supply line 112a, and the line connected to the downstream side of each reactor 11 is referred to as a hot water return line 112b.

[0046] The hot water supply line 112a is connected in parallel to the multiple reactors 11, and hot water can be supplied to each reactor 11 in parallel. A first hot water circulation water pump 832 and a second hot water circulation water pump 833 are arranged on the hot water supply line 112a. The first hot water circulation water pump 832 and the second hot water circulation water pump 833 are, for example, cascade pumps. By using a cascade pump that generates a large amount of heat when driven, it is possible to further heat the heat medium passing through the first hot water circulation water pump 832 and the second hot water circulation water pump 833.

[0047] Additionally, a circulation line 834 is arranged in the hot water supply line 112a, returning from the downstream side of the second hot water circulation water pump 833 to the upstream side. A safety valve 835 is arranged in this circulation line 834. The safety valve 835 relieves pressure when the pressure in the system between the second hot water circulation water pump 833 and the hot water line 112 exceeds a certain level, thereby suppressing a pressure increase. By arranging the safety valve 835, which relieves pressure in the event of an abnormality in the hot water line 112, in parallel with the second hot water circulation water pump 833, it is possible to achieve both a high flow rate circulation by the second hot water circulation water pump 833 and safe operation.

[0048] The hot water return line 112b is also connected in parallel to the plurality of reactors 11, and the hot water after heating can also be recovered in parallel for each reactor 11.

[0049] The three-way valve 30 is connected to the cold water line 111, the hot water line 112, and the reactor 11. The three-way valve 30 is disposed on each of the upstream and downstream sides of the reactor 11. The three-way valve 30 is configured to be able to select, by flow path switching, a cold water connection state in which the cold water line 111 is connected to the reactor 11, a hot water connection state in which the hot water line 112 is connected to the reactor 11, and a cut-off state in which the cold water line 111 and the hot water line 112 are cut off from the reactor 11.

[0050] The flow path switching of the three-way valve 30 is controlled by the control device 90. The heat medium is introduced into the reactor 11 through the three-way valve 30 arranged on the upstream side, and the heat medium is returned to the heat source device 81 side through the three-way valve 30 arranged on the downstream side.

[0051] The bypass path 31 is a flow path that allows the movement of a heat medium between the reactors 11. The bypass path 31 connects two reactors 11. The reactors 11 connected by the bypass path 31 may be adjacent reactors 11 or may be reactors 11 that are not adjacent but located apart.

[0052] 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 open and close by the control device 90.

[0053] 4 is a schematic diagram showing the configuration related to the flow of liquid in the reactor 11 of the carbon dioxide recovery device 1 of this embodiment. In the following description, the three-way valve 30 arranged upstream of the reactor 11 is referred to as the three-way valve 30a, and the three-way valve 30 arranged downstream of the reactor 11 is referred to as the three-way valve 30b.

[0054] 4, the reactor 11 includes an inlet-side flow path 33 connected to an inlet through which the heat transfer medium flows in, and an outlet-side flow path 34 connected to an outlet through which the heat transfer medium flows out. The bypass path 31 is connected to the outlet-side flow path 34 of the reactor 11 and is also connected to the inlet-side flow path 33 of another reactor 11.

[0055] A three-way valve 30a is disposed at the upstream end of the inlet flow path 33, and a three-way valve 30b is disposed at the downstream end of the outlet flow path 34. In the hot water connection state, the three-way valve 30a is connected to the hot water supply line 112a, and the three-way valve 30b is connected to the hot water return line 112b. In the cold water connection state, the three-way valve 30a is connected to the cold water supply line 111a, and the three-way valve 30b is connected to the cold water return line 111b.

[0056] The three-way valves 30a and 30b are configured to be able to adjust the flow rate. This flow rate adjustment function allows the flow rate of hot water to be adjusted when the hot water supply is connected, and the flow rate of cold water to be adjusted when the cold water supply is connected.

[0057] A temperature sensor 35 is disposed in the inlet-side flow path 33. A temperature sensor 36 and a flow rate sensor 37 are disposed in the outlet-side flow path 34. Measurement information from the temperature sensor 35, the temperature sensor 36, and the flow rate sensor 37 is transmitted to the control device 90.

[0058] 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 reactor 11 to heat or cool the reactors 11, so that the multiple reactors 11 repeatedly adsorb and desorb in time series.

[0059] The control device 90 controls the opening and closing of the first valve 21, the second valve 22, the third valve 23, and the fourth valve 24 provided in each reactor 11, and the opening and closing of each bypass valve 32. The control device 90 also controls the drive of the fan 61, the vacuum pump 62, the carbon dioxide capture pump 63, the first cold water circulation water pump 822, the second cold water circulation water pump 823, the first hot water circulation water pump 832, the second hot water circulation water pump 833, etc., and controls the opening and closing of the safety valve 825 and the safety valve 835.

[0060] 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.

[0061] <Carbon dioxide capture> Next, we will explain the control for capturing carbon dioxide by the control device 90. The carbon dioxide capture device 1 alternately performs an adsorption process in which the adsorbent 12 in the reactor 11 adsorbs carbon dioxide in a gas 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 stores the desorbed carbon dioxide in the carbon dioxide tank 66, thereby removing and capturing carbon dioxide from the air.

[0062] The adsorption process is a process in which carbon dioxide is adsorbed by the adsorbent 12 in the reactor 11. During the adsorption process, the third valve 23 and the fourth valve 24 of the reactor 11 are opened, and the first valve 21 and the second valve 22 are closed. In addition to controlling the opening and closing of the valves, the heat exchanger 70 controls the three-way valves 30a and 30b to a cold water connection state, allowing cold water to flow through the reactor 11 and cool the adsorbent 12 in the reactor 11. The fan 61 is driven, generating a gas flow from upstream to downstream, and gas containing carbon dioxide (e.g., atmospheric air) is drawn in through the third valve 23. The drawn gas passes through the adsorbent 12 in the reactor 11. At this time, the inside of the reactor 11 is cooled to room temperature (25°C) by the cold water, 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 system 1 through the fourth valve 24 and the adsorption line 101.

[0063] The desorption step is a step of desorbing carbon dioxide from the adsorbent 12 in the reactor 11. In the desorption step, the first valve 21, the third valve 23, and the fourth valve 24 of the reactor 11 are closed, and the second valve 22 is opened. The vacuum pump 62 is operated to draw air into the reactor 11 and reduce the pressure to create a vacuum or near-vacuum state. In addition to controlling the opening and closing of the valves, the heat exchanger 70 controls the three-way valves 30a and 30b to a hot water connection state, and hot water flows through the reactor 11 to supply thermal energy and raise the temperature of the adsorbent 12 in the reactor 11. 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 carbon dioxide desorbed through the carbon dioxide line 103 is stored in the carbon dioxide tank 66. In this embodiment, each step is controlled so that 12 of the 16 reactors 11 perform the adsorption step and the remaining four perform the desorption step.

[0064] <Heat source circuit> Next, the detailed configuration of the heat source circuit 80 will be described with reference to Fig. 5. Fig. 5 is a schematic diagram showing the configuration of the heat source circuit 80 of the carbon dioxide recovery device 1 of this embodiment.

[0065] As shown in FIG. 5, the heat source circuit 80 of this embodiment includes a heat source device 81, a heat source high-temperature water circuit 85 including a hot water tank 83, a heat source low-temperature water circuit 86 including a cold water tank 82, and a reservoir tank 88.

[0066] The heat source device 81 cools the heat medium introduced from the cold water tank 82 and heats the heat 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.

[0067] The heat source high temperature water circuit 85 circulates hot water between the hot water tank 83 and the heat source device 81. The heat source high temperature water circuit 85 includes the hot water tank 83, a hot water side heat source supply line 221, and a hot water side heat source return line 222.

[0068] The hot water tank 83 is a heat storage device that has a heat insulating function and can store a heat medium. The capacity of the hot water tank 83 is preferably at least five times the maximum flow rate discharged by the hot water circulation water pump 831, which will be described later. By setting the capacity of the hot water tank 83 to be large relative to the flow rate of the heat medium, it is possible to suppress temperature fluctuations of the hot water (heat medium) during heat load fluctuations within a predetermined temperature range (for example, within ±5°C). In other words, the hot water tank 83 functions as a buffer for heat load fluctuations.

[0069] A temperature sensor 830 for measuring the temperature of the heat medium is disposed inside the hot water tank 83. The measurement result of the temperature sensor 830 is output to the control device 90. The hot water tank 83 is connected to the heat source device 81 via a hot water side heat source supply line 221 and a hot water side heat source return line 222.

[0070] The hot water side heat source supply line 221 is a path through which the heat medium flows from the hot water tank 83 to the heat source device 81. A valve 301, a hot water side circulation water pump 831, a flow rate sensor 231, and a temperature sensor 232 are arranged in this order from upstream to downstream on the hot water side heat source supply line 221. The hot water side circulation water pump 831 is configured, for example, by a centrifugal pump or the like, and circulates the heat medium between the hot water tank 83 and the heat source device 81. The flow rate sensor 231 measures the flow rate of the heat medium flowing into the heat source device 81 and outputs the measurement result to the control device 90. The temperature sensor 233 measures the temperature of the heat medium flowing into the heat source device 81 and outputs the measurement result to the control device 90.

[0071] The hot water side heat source return line 222 is a path through which the heat medium flows from the heat source device 81 to the hot water tank 83. A temperature sensor 233 and a valve 302 are arranged in this order from upstream to downstream on the hot water side heat source return line 222. The temperature sensor 233 measures the temperature of the hot water flowing out from the heat source device 81 and outputs the measurement result to the control device 90.

[0072] A hot water supply line 112a and a hot water return line 112b are connected to the hot water tank 83. A valve 305, a water filter 234, a valve 306, a first hot water circulation water pump 832, a valve 322, and a valve 323 are arranged on the hot water supply line 112a on the hot water tank 83 side. A valve 321, a valve 303, a valve 304, and a temperature sensor 135 are arranged on the hot water return line 112b on the hot water tank 83 side. The inlet temperature of the hot water tank 83 detected by the temperature sensor 135 is output to the control device 90.

[0073] The heat-source high-temperature water circuit 85 of this embodiment recovers exhaust heat from the first intercooler 51 using hot water. The first intercooler 51 is arranged at any position in the heat-source high-temperature water circuit 85. Fig. 5 shows a first intercooler 51a arranged downstream of the valve 323 on the hot water return line 112a, and a first intercooler 51b arranged between the temperature sensor 233 and the valve 302 on the hot water side heat source return line 222. The first intercooler 51a and first intercooler 51b in Fig. 5 are only examples of possible locations, and the first intercooler 51 may be arranged at either the position of the first intercooler 51a or the first intercooler 51b.

[0074] Next, we will explain the heat-source low-temperature water circuit 86. The heat-source low-temperature water circuit 86 circulates cold water between the cold water tank 82 and the heat source device 81. The heat-source low-temperature water circuit 86 includes the cold water tank 82, a cold water-side heat source supply line 121, and a cold water-side heat source return line 122.

[0075] The cold water tank 82 is a heat storage device that has a heat insulating function and can store a heat medium. The capacity of the cold water tank 82 is preferably at least five times the maximum flow rate discharged by the cold water circulation water pump 821, which will be described later. By setting the capacity of the cold water tank 82 to be large relative to the flow rate of the heat medium, it is possible to suppress temperature fluctuations of the cold water (heat medium) during heat load fluctuations within a predetermined temperature range (for example, within ±5°C). In other words, the cold water tank 82 functions as a buffer for heat load fluctuations.

[0076] A temperature sensor 820 for measuring the temperature of the heat medium is disposed inside the cold water tank 82. The measurement result of the temperature sensor 820 is output to the control device 90. The cold water tank 82 is connected to the heat source device 81 via a cold water side heat source supply line 121 and a cold water side heat source return line 122.

[0077] The chilled water-side heat source supply line 121 is a path through which the heat medium flows from the chilled water tank 82 to the heat source device 81. The chilled water-side heat source supply line 121 is provided with a valve 307, a check valve 89, a chilled water-side circulation water pump 821, a flow rate sensor 131, and a temperature sensor 132. The check valve 89 prevents the flow of chilled water returning from the heat source device 81 to the chilled water tank 82. The chilled water-side circulation water pump 821 is configured, for example, by a centrifugal pump, and circulates the heat medium between the chilled water tank 82 and the heat source device 81. The flow rate sensor 131 measures the flow rate of the heat medium flowing into the heat source device 81 and outputs the measurement result to the control device 90. The temperature sensor 132 measures the temperature of the heat medium flowing into the heat source device 81 and outputs the measurement result to the control device 90.

[0078] A radiator bypass line 123 for cooling the heat medium and a heater bypass line 124 for heating the heat medium are connected to the cold water side heat source supply line 121. The radiator bypass line 123 and the heater bypass line 124 are temperature adjustment circuits that adjust the temperature of the heat medium flowing into the heat source device 81 to an operable temperature when the outside air temperature or heat load fluctuates.

[0079] The radiator bypass line 123 is connected between the chilled water-side circulation water pump 821 and the flow rate sensor 131 in the chilled water-side heat source supply line 121. A valve 141 and a radiator fan 142 are arranged in the radiator bypass line 123. The valve 141 can open and close the flow path and adjust the flow rate based on control signals from the control device 90. The radiator fan 142 is a heat dissipation device that cools the heat medium passing through the radiator bypass line 123. The cooling of the heat medium by the radiator bypass line 123 is performed mainly during high temperatures such as in summer. By cooling the heat medium by the radiator bypass line 123, the temperature of the chilled water introduced into the heat source device 81 is controlled to be equal to or lower than a preset threshold value.

[0080] The heater bypass line 124 is located in the cold water-side heat source supply line 121 between the cold water-side circulation water pump 821 and the flow rate sensor 131, and is connected to the inside of the radiator bypass line 123. A valve 308 and a heater 150 are arranged in the heater bypass line 124. The heater 150 is driven by a control signal or a relay drive signal from the control device 90, and heats the heat medium flowing through the heater bypass line 124. The heating of the heat medium by the heater bypass line 124 is performed mainly when the temperature is low, such as during start-up in winter. By heating the heat medium by the heater bypass line 124, the temperature of the heat medium introduced into the heat source device 81 is controlled to be equal to or higher than a preset threshold value.

[0081] The chilled water side heat source return line 122 is a path through which the heat medium flows from the heat source device 81 to the chilled water tank 82. A temperature sensor 133, valves 309, 310, 311, and 312 are arranged in this order from upstream to downstream on the chilled water side heat source return line 122. The temperature sensor 132 measures the temperature of the chilled water flowing out from the heat source device 81 and outputs the measurement result to the control device 90.

[0082] A chilled water supply line 111a and a chilled water return line 111b are connected to the chilled water tank 82. A valve 315, a water filter 134, a valve 316, a first chilled water circulation water pump 822, a valve 325, and a valve 326 are arranged on the chilled water supply line 111a on the chilled water tank 82 side. A valve 324, a valve 313, a valve 314, and a temperature sensor 235 are arranged on the chilled water return line 111b on the chilled water tank 82 side. The inlet temperature of the chilled water tank 82 detected by the temperature sensor 235 is output to the control device 90.

[0083] The heat-source low-temperature water circuit 86 of this embodiment recovers exhaust heat from the second intercooler 52 using cold water. The second intercooler 52 is arranged at any position in the heat-source low-temperature water circuit 86. Fig. 5 shows the second intercooler 52a arranged upstream of the valve 324 on the cold water return line 111b, and the second intercoolers 52b and 52c arranged in the equipment heat recovery circuit 87. The second intercooler 52a, second intercooler 52b, and second intercooler 52c in Fig. 5 are only examples of possible locations, and the second intercooler 52 may be arranged at any one of the second intercooler 52a, second intercooler 52b, and second intercooler 52c.

[0084] Next, a description will be given of the equipment heat recovery circuit 87, which is a possible location for the second intercooler 52b and the second intercooler 52c. The equipment heat recovery circuit 87 cools target equipment such as the vacuum pump 62, the carbon dioxide recovery pump 63, and the second intercooler 52b and / or the second intercooler 52c, and also increases the temperature of the heat medium.

[0085] The equipment heat recovery circuit 87 is connected in parallel to the heat-source low-temperature water circuit 86. The equipment heat recovery circuit 87 of this embodiment includes a first equipment heat cooling line 126 that exchanges heat with the second intercooler 52b, and a second equipment heat cooling line 127 that exchanges heat with the vacuum pump 62 and the carbon dioxide recovery pump 63.

[0086] The first equipment thermal cooling line 126 has its upstream end connected to the chilled water side heat source return line 122 and its downstream end connected to the chilled water side heat source supply line 121. In this embodiment, the connection point of the upstream end of the first equipment thermal cooling line 126 is between valve 309 and valve 310 on the chilled water side heat source return line 122. The connection point of the lower end of the first equipment thermal cooling line 126 is between valve 307 on the chilled water side heat source supply line 121 and chilled water side circulation water pump 821.

[0087] The first equipment heat cooling line 126 is connected to the intercooler 64 that generates steam condensation heat, and cools the intercooler 64 with cold water to recover the steam condensation heat as waste heat. The cold water is heated by heat exchange with the intercooler 64 and then sent to the cold water side heat source supply line 121.

[0088] A flow rate sensor 841 and a temperature sensor 842 are arranged upstream of the intercooler 64 on the first equipment thermal cooling line 126, and a temperature sensor 843 and a valve 317 are arranged downstream of the intercooler 64. The flow rate sensor 841 measures the flow rate of the heat medium before heat exchange with the intercooler 64 and outputs the measurement result to the control device 90. The temperature sensor 842 measures the temperature of the heat medium before heat exchange with the intercooler 64 and outputs the measurement result to the control device 90. The temperature sensor 843 measures the temperature of the heat medium after heat exchange with the intercooler 64 and outputs the measurement result to the control device 90.

[0089] The second equipment thermal cooling line 127 has its upstream end connected to the chilled water side heat source return line 122 and its downstream end connected to the chilled water side heat source supply line 121. In this embodiment, the connection point of the upstream end of the second equipment thermal cooling line 127 is between the valves 310 and 311 on the chilled water side heat source return line 122. The connection point of the lower end of the second equipment thermal cooling line 127 is between the valve 307 on the chilled water side heat source supply line 121 and the chilled water side circulation water pump 821, which is upstream of the connection point of the downstream end of the first equipment thermal cooling line 126.

[0090] Moreover, the second equipment thermal cooling line 127 of this embodiment includes a first branch line 127a for cooling the vacuum pump 62 and a second branch line 127b for cooling the carbon dioxide capture pump 63.

[0091] The first branch line 127a is connected to the vacuum pump 62 and uses cold water to cool the vacuum pump 62. The heat medium is heated by heat exchange with the vacuum pump 62 and then merges with the second branch line 127b, and is sent to the cold water side heat source supply line 121.

[0092] A flow rate sensor 851 and a temperature sensor 852 are arranged upstream of the vacuum pump 62 on the first branch line 127a, and a temperature sensor 853 is arranged downstream of the vacuum pump 62. The flow rate sensor 851 measures the flow rate of the heat medium before heat exchange with the vacuum pump 62 and outputs the measurement result to the control device 90. The temperature sensor 852 measures the temperature of the heat medium before heat exchange with the vacuum pump 62 and outputs the measurement result to the control device 90. The temperature sensor 853 measures the temperature of the chilled water after heat exchange with the vacuum pump 62 and outputs the measurement result to the control device 90.

[0093] The second branch line 127b is connected to the carbon dioxide capture pump 63 and uses a heat medium to cool the carbon dioxide capture pump 63. The heat medium is heated by heat exchange with the carbon dioxide capture pump 63 and then merges with the first branch line 127a, and is sent to the chilled water side heat source supply line 121.

[0094] A flow rate sensor 861 and a temperature sensor 862 are arranged on the second branch line 127b upstream of the carbon dioxide capture pump 63, and a temperature sensor 863 is arranged downstream of the carbon dioxide capture pump 63. The flow rate sensor 861 measures the flow rate of the heat medium before heat exchange with the carbon dioxide capture pump 63 and outputs the measurement result to the control device 90. The temperature sensor 862 measures the temperature of the heat medium before heat exchange with the carbon dioxide capture pump 63 and outputs the measurement result to the control device 90. The temperature sensor 863 measures the temperature of the heat medium after heat exchange with the carbon dioxide capture pump 63 and outputs the measurement result to the control device 90.

[0095] An equipment cooling pump 870 is arranged upstream of the branch point of the first branch line 127a and the second branch line 127b in the second equipment thermal cooling line 127. Furthermore, valves 318 and 319 are arranged downstream of the junction of the first branch line 127a and the second branch line 127b in the second equipment thermal cooling line 127. Furthermore, when the second intercooler 52c is arranged, the second intercooler 52c is arranged downstream of the valve 319.

[0096] The equipment cooling pump 870 of this embodiment is configured by a cascade pump having a sufficient head to pump the heat medium without being hindered by the high pressure loss of the vacuum pump 62 and the carbon dioxide capture pump 63, which are the equipment for which heat recovery is performed. The heat generated by driving the equipment cooling pump 870 is also recovered as exhaust heat by the cold water.

[0097] As described above, the equipment heat recovery circuit 87 recovers the exhaust heat of the vacuum pump 62 and the carbon dioxide recovery pump 63 into a heat medium to cool the target equipment, and the heat recovery makes it possible to cause the heat medium to flow into the heat source device 81 at a high temperature potential.

[0098] Furthermore, when the second intercooler 52b or the second intercooler 52c is provided, the heat of steam condensation of the second intercooler 52b or the second intercooler 52c can be recovered into the heat medium, and the heat medium can be caused to flow into the heat source device 81 at a high temperature potential. The cold water after the exhaust heat recovery merges with the cold water-side heat source supply line 121 through which the cold water discharged from the cold water tank 82 flows, and is introduced into the heat source device 81. The cold water after the exhaust heat recovery is heated to an appropriate temperature range.

[0099] In this embodiment, the cold water is further adjusted to an appropriate temperature range before entering the heat source device 81 by the radiator bypass line 123 for cooling the cold water or the heater bypass line 124 for heating the cold water, so that even in operations with large fluctuations in the heat load, it is possible to smooth out the heat fluctuations over time and keep the inflow temperature to the heat source device 81 constant.

[0100] Next, the configuration of the reservoir tank 88 will be described. The reservoir tank 88 is a tank capable of storing a heat medium. The reservoir tank 88 is connected to the hot water tank 83 and the cold water tank 82. A valve 320 is disposed between the reservoir tank 88 and the hot water tank 83, and another valve 321 is disposed between the reservoir tank 88 and the cold water tank 82. When the amount of heat medium stored in the hot water tank 83 needs to be adjusted, the valve 320 is opened, and the heat medium is transferred between the reservoir tank 88 and the hot water tank 83. Similarly, when the amount of heat medium stored in the cold water tank 82 needs to be adjusted, the valve 321 is opened, and the heat medium is transferred between the reservoir tank 88 and the cold water tank 82. A level sensor 880 for determining the amount of heat medium stored is disposed inside the reservoir tank 88. The measurement result of the level sensor 880 is output to the control device 90. The control device 90 uses the measurement result of the level sensor 880 to determine whether the reservoir tank 88 is usable or not.

[0101] <Heat exchange of high-temperature gas> Next, the heat exchange between superheated steam and hot water in the first intercooler 51 and the heat exchange between supercooled liquid and cold water by the second intercooler 52 will be described with reference to Figures 6 to 8. Figure 6 is a schematic diagram of the high-temperature gas cooling mechanism by the first intercooler 51 and the second intercooler 52. Figure 7 is a graph showing the relationship between the temperature of superheated steam of high-temperature gas and the temperature of hot water, which changes due to cooling by the first intercooler 51. Figure 8 is a graph showing the relationship between the temperature of supercooled liquid and the temperature of cold water, which changes due to cooling by the second intercooler 52.

[0102] 5, and is supplied with hot water from the heat source high-temperature water circuit 85. High-temperature gas containing carbon dioxide and superheated steam is delivered to the first intercooler 51 from the carbon dioxide recovery pump 63, and heat is exchanged between this high-temperature gas and the hot water.

[0103] As shown in FIG. 7 , the superheated steam delivered from the carbon dioxide capture pump 63 exchanges heat with hot water heated by the heat source 81 in the first intercooler 51, lowering its temperature from 120°C to approximately 80°C and becoming a supercooled liquid. Through this heat exchange, the specific enthalpy [kJ / kg] of the superheated steam gradually decreases from 120°C, stabilizes at 100°C, the liquefaction temperature of water, and then gradually decreases to 80°C. Meanwhile, the hot water with which the heat exchange takes place is heated from 75°C to 82°C, and the specific enthalpy [kJ / kg] of the hot water gradually increases. In this embodiment, the circuit is designed so that the temperature of the superheated steam exceeds the temperature of the hot water even at the minimum pinch temperature, the temperature difference between which is closest. This allows the first stage of cooling by the first intercooler 51, which cools the superheated steam to a supercooled liquid, to be performed appropriately.

[0104] 5, or the position of the second intercooler 52b or the position of the second intercooler 52b or the second intercooler 52c, and is supplied with cold water from the heat source low-temperature water circuit 86. Carbon dioxide and supercooled liquid are sent to the second intercooler 52 from the first intercooler 51, and heat exchange takes place between this supercooled liquid and the cold water.

[0105] As shown in FIG. 8 , the supercooled liquid delivered from the second intercooler 52 is cooled from 80°C to approximately 30°C by heat exchange with the cold water returned from the reactor 11 in the second intercooler 52. This heat exchange causes the specific enthalpy [kJ / kg] of the supercooled liquid to gradually decrease from 80°C to 30°C. Meanwhile, the cold water with which the heat is exchanged is heated from 25°C to 35°C, and the specific enthalpy [kJ / kg] of the cold water gradually increases. In this embodiment, the circuit is designed so that the temperature of the supercooled liquid exceeds the temperature of the cold water even at the minimum pinch temperature, which is the closest temperature difference. Therefore, the second stage of cooling by the second intercooler 52, which cools the supercooled liquid to the room temperature of 30°C, is performed appropriately.

[0106] <Heat medium flow rate control> In this embodiment, the system is configured to be able to adjust the ratio between the flow rate of hot water (hot water amount) supplied to the first intercooler 51 and the flow rate of cold water (cold water amount) supplied to the second intercooler 52. Returning to Fig. 6, the configuration for adjusting the amounts of hot water and cold water will be described.

[0107] 6, the first intercooler 51 includes a first bypass line 511, a stop valve 512, and a flow rate adjustment mechanism 513. Note that the first bypass line 511, the stop valve 512, and the flow rate adjustment mechanism 513 are not shown in FIG.

[0108] The first bypass line 511 is a flow path for hot water that connects the upstream side and downstream side of the first intercooler 51. The hot water that passes through the first bypass line 511 flows downstream without passing through the first intercooler 51.

[0109] The stop valve 512 is an opening / closing device that opens and closes the flow path of the first bypass line 511. The stop valve 512 is switched between a closed state and an open state by the control device 90. When the stop valve 512 is controlled to the closed state, the hot water is heat exchanged in the first intercooler 51 without flowing into the first bypass line 511. When the stop valve 512 is controlled to the open state, the hot water flows not only into the first intercooler 51 but also into the first bypass line 511.

[0110] The flow rate adjustment mechanism 513 is disposed upstream of the first intercooler 51 and downstream of the connection portion of the first bypass line 511. The flow rate adjustment mechanism 513 is configured by a mechanism that can adjust the amount of hot water flowing into the first intercooler 51. The flow rate adjustment mechanism 513 may have a function of closing the flow path.

[0111] The second intercooler 52 also includes a second bypass line 521, a stop valve 522, and a flow rate adjustment mechanism 523. Note that the second bypass line 521, the stop valve 522, and the flow rate adjustment mechanism 523 are not shown in Fig. 5 .

[0112] The second bypass line 521 is a flow path for cold water that connects the upstream side and downstream side of the second intercooler 52. The cold water that passes through the second bypass line 521 flows downstream without passing through the second intercooler 52.

[0113] The stop valve 522 is an opening / closing device that opens and closes the flow path of the second bypass line 521. The stop valve 522 is switched between a closed state and an open state by the control device 90. When the stop valve 522 is controlled to the closed state, the chilled water is heat exchanged in the second intercooler 52 without flowing into the second bypass line 521. When the stop valve 522 is controlled to the open state, the chilled water flows not only into the second intercooler 52 but also into the second bypass line 521.

[0114] Flow rate adjustment mechanism 523 is disposed upstream of second intercooler 52 and downstream of the connection portion of second bypass line 521. Flow rate adjustment mechanism 523 is configured by a mechanism that can adjust the amount of chilled water flowing into second intercooler 52. Flow rate adjustment mechanism 523 may have a function of closing the flow path.

[0115] The control device 90 can adjust the amount of heat recovered by the first intercooler 51 by controlling the stop valve 512 and the flow rate adjustment mechanism 513 to adjust the amount of hot water flowing into the first intercooler 51. The control device 90 can also adjust the amount of heat recovered by the second intercooler 52 by controlling the stop valve 522 and the flow rate adjustment mechanism 523 to adjust the amount of cold water flowing into the second intercooler 52. Therefore, the control device 90 can stop the supply of hot water to the first intercooler 51 by controlling the stop valve 512 and the flow rate adjustment mechanism 513, while adjusting the amount of cold water to the second intercooler 52 in accordance with the heat balance described below by controlling the stop valve 522 and the flow rate adjustment mechanism 523.

[0116] <Operating mode> The control device 90 of this embodiment has three operation modes: a cascade heat recovery mode, a low-temperature side heat recovery mode, and an auxiliary heat source operation mode. When the heating demand of the heat source device 81 is equal to or less than the exhaust heat recovery amount, the cascade heat recovery mode or the low-temperature side heat recovery mode is selected, and when the heating demand of the heat source device 81 exceeds the exhaust heat recovery amount, the auxiliary heat source operation mode is selected. Each operation mode will be described below.

[0117] The cascade heat recovery mode is a mode in which high-temperature gas containing carbon dioxide and superheated steam delivered from the carbon dioxide recovery pump 63 is cooled by the first intercooler 51 of the heat source high-temperature water circuit 85, and the cooled supercooled liquid is cooled by the second intercooler 52 of the heat source low-temperature water circuit 86.

[0118] FIG. 9 is a bar graph showing the respective component ratios of the heating load of the heat-source high-temperature water circuit 85 and the waste heat recovery of the heat-source low-temperature water circuit 86. As shown in FIG. 9, in the cascade heat recovery mode, the hot water in the heat-source high-temperature water circuit 85 is heated by the first intercooler 51, so the amount of heat generated by the heat source device 81 can be reduced relative to the amount of heat supplied to the reactor 11. For example, if the hot water is heated to 82°C only by raising the temperature of the heat source device 81 without using the first intercooler 51, the condensation pressure is high and the pressure difference is large, resulting in a large amount of work required. In contrast, in the cascade heat recovery mode, the heat source device 81 heats the water to 75°C, and the remaining temperature can be raised to 82°C by utilizing the heat generated when the first intercooler 51 cools the superheated steam from 120°C to 80°C. As in this example, reducing the heating work performed by the heat source device 81 by 5°C improves the heating COP by approximately +7%, resulting in a power-saving effect for the heat source device 81.

[0119] In addition, the exhaust heat recovery of the heat source low-temperature water circuit 86 in the cascade heat recovery mode includes heat recovered from the cold water input to the heat source device 81, heat recovered when the supercooled liquid is cooled from 80°C to 40°C in the second intercooler 52, and heat recovered from the vacuum pump 62 and the carbon dioxide recovery pump 63.

[0120] Next, the low-temperature side heat recovery mode will be described. The low-temperature side heat recovery mode is a mode in which high-temperature gas containing carbon dioxide and superheated steam, which is sent out from the carbon dioxide recovery pump 63, is cooled by the second intercooler 52 of the heat-source low-temperature water circuit 86. In the low-temperature side heat recovery mode, the gas does not pass through the first intercooler 51, and therefore the temperature of the hot water in the heat-source high-temperature water circuit 85 is not increased by the first intercooler 51.

[0121] Next, with reference to Fig. 10, a description will be given of the criteria for selecting the most energy-efficient mode from the cascade heat recovery mode and the low-temperature side heat recovery mode when the heating demand is lower than the amount of exhaust heat recovered. Fig. 10 is a graph showing the relationship between the heat exchange amount and the heating COP of the heat source device 81. The heating COP can be calculated, for example, by dividing the heating amount of the heat source device 81 by the amount of electric power input to the heat source device 81. The heating amount of the heat source device 81 can be considered to be equal to the heating load.

[0122] As shown in FIG. 10, the higher the heating COP of the heat source device 81, the less power consumption it requires; therefore, a higher heating COP is preferable. The heating COP of the heat source device 81 has an optimal heat exchange amount at which the heating COP is maximized, depending on the device configuration, conditions, and other factors. The heating COP of the heat source device 81 in the example of FIG. 9 increases gradually with an increase in the heat exchange amount, reaches a maximum at an optimal heat exchange amount, and then gradually decreases. Therefore, adjusting the heat exchange amount so that the heating COP is maximized can reduce power consumption and achieve energy savings. For example, if the heat exchange amount is greater than the heat exchange amount for the maximum heating COP, reducing the heat exchange amount of the heat source device 81 will bring the heating COP closer to the maximum. Conversely, if the heat exchange amount is smaller than the heat exchange amount for the maximum heating COP, increasing the heat exchange amount of the heat source device 81 will bring the heating COP closer to the maximum.

[0123] Therefore, the control device 90 determines that a mode that can bring the heating COP closer to the maximum heating COP is a mode that can save energy. For example, if a heating load (heat exchange amount) greater than the heat exchange amount of the maximum heating COP is required, a mode that reduces the heat exchange amount of the heat source device 81 may be selected. In this case, the cascade heat recovery mode, in which the first intercooler 51 is responsible for part of the temperature increase, is selected. If a heating load (heat exchange amount) less than the heat exchange amount of the maximum heating COP is required, it is better to increase the heat exchange amount of the heat source device 81, so the low-temperature side heat recovery mode is selected instead of the cascade heat recovery mode.

[0124] The auxiliary heat source operation mode is a mode in which the chilled water circulating through the heat-source low-temperature water circuit 86 is heated by the heater 150 and then sent to the heat source device 81. The auxiliary heat source operation mode is a mode that is selected when the amount of exhaust heat recovered by the heat-source low-temperature water circuit 86 exceeds the heating load of the heat-source high-temperature water circuit 85. An example of a case in which the amount of exhaust heat recovered by the heat-source low-temperature water circuit 86 exceeds the heating load of the heat-source high-temperature water circuit 85 is when the temperature of the chilled water flowing into the heat source device 81 is lower than the start-up temperature set for the heat source device 81.

[0125] Next, an explanation will be given of the operation control by the control device 90. Fig. 11 is a flowchart showing an example of the process of the operation control of the carbon dioxide capture device 1 of this embodiment. The flowchart shown in Fig. 11 is the start-up sequence of the carbon dioxide capture device 1.

[0126] In step S11, the control device 90 acquires environmental conditions such as the outside air temperature (temperature), humidity (relative humidity), CO2 concentration in the atmosphere to be sucked in, solar radiation, wind speed, etc. This information may be acquired based on detection values ​​of various sensors (not shown), or may be acquired from meteorological data (temperature, relative humidity, carbon dioxide concentration) of the installation area where the carbon dioxide capture device 1 is operated.

[0127] In step S12, the control device 90 sets an operation schedule for the carbon dioxide capture device 1 based on the acquired environmental conditions.

[0128] The ambient temperature (temperature) and humidity (relative humidity) acquired as environmental conditions are used to predict the time to execute the desorption process in the operation schedule. The temperature and relative humidity acquired as environmental conditions are used to predict the amount of water adsorbed by the adsorbent 12. Specifically, when operating under conditions of high relative humidity, the amount of water adsorbed by the adsorbent 12 increases, which in turn increases the reaction heat required to desorb water during desorption, resulting in a larger heating load. Meanwhile, the heat of condensation of water passing through the first intercooler 51 and the second intercooler 52 after desorption from the adsorbent 12 increases relatively because the amount of water vapor increases. Therefore, the heating load and cooling load requirements on the heat source circuit 80 also increase. The control device 90 determines whether the standard estimated time for desorption is possible, taking into account the heating capacity and cooling capacity of the heat source device 81, and determines the desorption time that will achieve an appropriate desorption state.

[0129] The CO2 concentration acquired as an environmental condition is used to predict the time to perform the adsorption process in the operation schedule. Although the atmospheric carbon dioxide concentration varies little depending on the location and time, by taking the atmospheric carbon dioxide concentration into account, the adsorption time can be predicted based on the atmospheric carbon dioxide concentration to be adsorbed. The control device 90 sets the execution time of the adsorption process so that the adsorption process time is shorter than a preset reference time in places where the carbon dioxide concentration is high, and longer than the reference time in places where the carbon dioxide concentration is low.

[0130] The solar radiation and wind speed acquired as environmental conditions, along with the outside air temperature, are used to calculate the energy loss caused by heating and cooling. The control device 90 calculates the loss caused in the reactor 11 and heat source circuit 80 of the carbon dioxide capture device 1 based on the solar radiation, wind speed, and outside air temperature. The loss may be calculated using machine learning or the like based on formulas, tables, etc. that are set based on the operating history of the carbon dioxide capture device 1, past experimental data, etc. The calculated loss is reflected in the execution times of the adsorption process and desorption process, allowing for more accurate calculation of the execution times of the adsorption process and desorption process.

[0131] In a configuration in which multiple reactors 11 are operated in rotation, such as the carbon dioxide capture device 1 of this embodiment, the execution time of the adsorption process and the execution time of the desorption process affect the amount of carbon dioxide adsorbed within the operation time. By accurately calculating the execution time of the adsorption process and the desorption process based on environmental conditions acquired in advance and determining an operation schedule, the amount of carbon dioxide adsorbed within the operation time can be maximized. The control device 90 sets the ratio of adsorption time to desorption time, the timing of executing each process in each reactor 11, etc. as the operation schedule.

[0132] In step S13, the control device 90 calculates the amounts of carbon dioxide and water adsorbed by the adsorbent 12 based on the set operation schedule. The amount of carbon dioxide adsorption can be calculated using "density x air volume x (concentration after adsorption - concentration before adsorption)". The difference in concentration before and after adsorption can be obtained in real time by the carbon dioxide sensor 26. The amount of water adsorption can be calculated using "density x air volume x (absolute air humidity before adsorption - absolute humidity after adsorption)". The air volume obtained as an environmental condition can be used.

[0133] In step S14, the control device 90 predicts the demand for heating load when the desorption process is being performed in the reactor 11. The control device 90 predicts the demand for heating load when the desorption process is being performed based on the sum of the heating loads of the reactors 11 that are simultaneously performing the desorption process on the operation schedule. In this embodiment, the desorption process is performed in four reactors 11 simultaneously, and therefore the demand for heating load is predicted and calculated based on the sum of the heating loads of the four reactors 11.

[0134] An example of a method for calculating the heating load per reactor 11 will be described. The heating time in the desorption process is determined by the operation schedule. The heating load (amount of heat required for heating) within the heating time per reactor 11 can be calculated based on the "reactor thermal mass + reaction heat + heat loss." The "reactor thermal mass" can be calculated in advance from, for example, the amount of adsorbent 12, the mass and specific heat of a heat exchanger (not shown) in which the adsorbent 12 is placed inside the reactor 11, and other components in the reactor 11. The "reaction heat" in the desorption process is determined by the amount of carbon dioxide and the amount of water adsorbed by the reactor 11. The control device 90 calculates the "reaction heat" from the amount of carbon dioxide and the amount of water adsorbed calculated in the process of step S13. The "heat loss" can be determined by the temperature difference between the outside air temperature and the reactor 11. The control device 90 calculates the "heat loss" using the outside air temperature acquired in step S11 and the temperature detected by the temperature sensor 27.

[0135] In step S15, the control device 90 predicts the amount of exhaust heat recovered based on the operating conditions (cooling requirements) of the target equipment such as the first intercooler 51, the second intercooler 52, the vacuum pump 62, and the carbon dioxide recovery pump 63 of the carbon dioxide recovery device 1 and the operating conditions (cooling requirements) of the reactor 11.

[0136] The amount of exhaust heat recovered can be calculated based on the following: heat recovered during pre-cooling after desorption in the reactor 11, heat recovered during steam condensation in the first intercooler 51 and the second intercooler 52, heat recovered during cooling in the vacuum pump 62 and the carbon dioxide recovery pump 63, heat recovered from other pumps, etc., minus heat loss occurring in the circuit. The "heat recovered during pre-cooling after desorption in the reactor 11" can be calculated by multiplying the difference between the desorption temperature and the cooling temperature by the reactor thermal mass. For example, if pre-cooling is performed to a room temperature of 30°C at a desorption temperature of 80°C, the "heat recovered during pre-cooling after desorption in the reactor 11" can be calculated by multiplying 50°C (ΔT) by the reactor thermal mass. The "heat recovered during steam condensation in the first intercooler 51 and the second intercooler 52" can be calculated by predicting the amount of steam condensation heat required for condensation after the desorption process based on the amount of water adsorption, since the amount of water adsorbed in the reactor 11 that performs the adsorption process is known. "Heat recovery during cooling of the vacuum pump 62 and the carbon dioxide capture pump 63" can be calculated based on the temperature difference between the inlet and outlet of the cooling heat medium supplied to the vacuum pump 62 and the carbon dioxide capture pump 63 for cooling. "Heat recovery from other pumps, etc." can also be calculated based on the temperature difference between the inlet and outlet of the cooling heat medium supplied to each device. Examples of other pumps include the cold water circulation water pump 821, the first cold water circulation water pump 822, the second cold water circulation water pump 823, the hot water circulation water pump 831, the first hot water circulation water pump 832, and the second hot water circulation water pump 833. "Heat loss occurring within the circuit" can be determined by referring to a map, table, calculation formula, etc. that is preset based on the relationship between the outside air temperature and the average pipe temperature.

[0137] In step S16, the control device 90 predicts the amount of heat recovered from the superheated steam sent out from the carbon dioxide capture pump 63. The amount of heat recovered from the hot steam can be found from the amount of heat of steam condensation in the first intercooler 51 and the second intercooler 52. As explained in the processing of step S15, the amount of heat of steam condensation can be calculated based on the sum of the combined amounts of water adsorption in the adsorption steps of the reactors 11 that simultaneously perform the adsorption steps.

[0138] In step S17, the control device 90 determines whether the heating demand exceeds the exhaust heat recovery amount in order to consider the heat balance between the heating demand and the exhaust heat recovery amount. If the heating demand exceeds the exhaust heat recovery amount, the control device 90 proceeds to step S18 (step S17; Yes), and if the heating demand does not exceed the exhaust heat recovery amount, the control device 90 proceeds to step S19 (step S17; No).

[0139] In step S18, because the amount of exhaust heat recovery exceeds the heating demand, the control device 90 executes the auxiliary heat source operation mode in which the heater 150 is started to heat the chilled water. In the auxiliary heat source operation mode, the heater 150 heats the chilled water, and the amount of exhaust heat recovery in the heat source low-temperature water circuit 86 is ensured.

[0140] In step S19, the control device 90 predicts the operating performance based on the chilled water inlet temperature and hot water inlet temperature of the heat source device 81. In this embodiment, the control device 90 obtains the chilled water inlet temperature of the heat source device 81 from temperature sensor 132 and the hot water inlet temperature of the heat source device 81 from temperature sensor 232, and calculates a heating coefficient of performance (COP), which indicates the operating performance, based on the temperature difference between the chilled water inlet temperature and the hot water inlet temperature. The heating COP can be calculated by dividing the "heating load" by the "power consumption of the heat source device." The "heating load" can be calculated by the processing in step S15. The "power consumption of the heat source device" is the power consumption of the heat source device 81 and is determined by the relationship between the temperature and heating load generated by the heat source to be supplied to the heating side, and the temperature and amount of chilled water flowing into the heat source device based on the predicted exhaust heat recovery on the cooling side. These relationships can be obtained by previously setting a heating COP map, table, or calculation formula on the heat source device 81 side.

[0141] In step S20, the control device 90 selects the mode that can save energy from the cascade heat recovery mode or the low-temperature side heat recovery mode based on the heating COP. If the mode that can save energy is the cascade heat recovery mode (step S20; Yes), the control device 90 proceeds to step S21 and executes the cascade heat recovery mode in step S21. If energy cannot be saved (step S20; No), the control device 90 proceeds to step S22 and executes the low-temperature side heat recovery mode in step S22.

[0142] In this manner, the control device 90 controls each of the heat-source hot water circuit 85 and the heat-source cold water circuit 86 based on the selected operation mode.

[0143] Furthermore, the control device 90 can also adjust the ratio between the amount of heat recovered by the first intercooler 51 and the amount of heat recovered by the second intercooler 52. The amount of heat recovered by the first intercooler 51 can be controlled, for example, by adjusting the flow rate of hot water. The amount of heat recovered by the second intercooler 52 can be controlled, for example, by adjusting the flow rate of cold water. Therefore, the amount of heating can be adjusted to approach the maximum COP set for the heat source device 81.

[0144] As described above, the carbon dioxide recovery device 1 of this embodiment includes the reactor 11 having the adsorbent 12 therein and performing an adsorption step of sucking a gas containing carbon dioxide into the adsorbent 12 to adsorb the carbon dioxide, and a desorption step of heating the adsorbent 12 in a state where the atmosphere around the adsorbent 12 is reduced in pressure to desorb carbon dioxide from the adsorbent 12, the heat exchanger 70 capable of heating by supplying hot water (heat medium for heating) to the reactor 11 and cooling by supplying cold water (heat medium for cooling), and a first intercooler that cools the gas containing carbon dioxide and water vapor desorbed in the desorption step. The heat exchange device 70 includes a first intercooler (first cooler) 51 that cools the gas containing carbon dioxide and water vapor desorbed in the desorption process, and a second intercooler (second cooler) 52 that cools the gas containing carbon dioxide and water vapor desorbed in the desorption process.The heat exchange device 70 includes a heat pump type heat source 81 that heats hot water and cools cold water, a heat source high temperature water circuit 85 that heats the hot water that heated the reactor 11 with the heat source 81 and recovers exhaust heat from the first intercooler 51 using the hot water, and a heat source low temperature water circuit 86 that cools the cold water that cooled the reactor 11 with the heat source 81 and recovers exhaust heat from the second intercooler 52 using the cold water.

[0145] In addition, the carbon dioxide recovery method of this embodiment heats hot water and cools cold water using a heat pump type heat source device 81 provided in the heat exchange device 70, heats the hot water that heated the reactor 11 using the heat source device 81, and recovers exhaust heat from the first intercooler 51 using the hot water, cools the cold water that cooled the reactor 11 using the heat source device 81, and recovers exhaust heat from the second intercooler 52 using the cold water.

[0146] By configuring the carbon dioxide capture device 1 and carbon dioxide capture method in this way, the heat source high-temperature water circuit 85 can heat hot water by utilizing the heat obtained by cooling the superheated steam in the first intercooler 51. The heat source low-temperature water circuit 86 can increase the temperature of the cold water flowing into the heat source device 81 by utilizing the heat obtained by cooling the supercooled liquid in the second intercooler 52, thereby improving the COP. A highly energy-efficient carbon dioxide capture device 1 can be realized that utilizes the cooling of high-temperature gas containing carbon dioxide and superheated steam.

[0147] In addition, the carbon dioxide recovery device 1 of this embodiment further includes a control device 90 that controls the flow rate of hot water flowing to the first intercooler 51 and the flow rate of cold water flowing to the second intercooler 52 based on the balance between the heating load on the heat source high-temperature water circuit 85 and the amount of exhaust heat recovered in the heat source low-temperature water circuit 86.

[0148] This allows the control device 90 to control the heat exchange between the first intercooler 51 and the second intercooler 52 according to the balance between the heating load during operation and the amount of exhaust heat recovered, thereby enabling the carbon dioxide recovery device 1 to be operated with higher energy efficiency in accordance with environmental and operating conditions.

[0149] In addition, in this embodiment, the control device 90 calculates the amount of carbon dioxide and water recovered based on the environmental conditions of the outside air, calculates the heating load based on the predicted amount of carbon dioxide and water recovered, calculates the amount of exhaust heat recovered in the heat source low-temperature water circuit 86 based on the cooling requirement of the target equipment performing the adsorption process or desorption process or the cooling requirement of the reactor 11, predicts the heating COP during operation of the heat source device 81 based on the respective temperatures and heating loads of the hot water and cold water supplied to the heat source device 81, and if the heating COP can be improved, selects a cascade heat recovery mode (first heat recovery mode) in which exhaust heat is recovered in each of the first intercooler 51 and the second intercooler 52, and if the heating COP cannot be improved even when the cascade heat recovery mode is selected, selects a low-temperature side heat recovery mode (second heat recovery mode) in which exhaust heat is recovered in the second intercooler 52.

[0150] As a result, depending on environmental conditions such as the temperature and humidity of the intake air, a more appropriate mode is selected from the cascade heat recovery mode, in which exhaust heat is recovered by both the first intercooler 51 and the second intercooler 52, and the low-temperature side heat recovery mode, in which exhaust heat is recovered by the second intercooler 52, in terms of energy efficiency. For example, if the amount of exhaust heat from the second intercooler 52 in the heat-source low-temperature water circuit 86 increases and it becomes impossible to effectively utilize the exhaust heat, the cascade heat recovery mode is selected, and exhaust heat from the second intercooler 52 is recovered and exhaust heat from the first intercooler 51 is recovered in the heat-source high-temperature water circuit 85. This prevents overflow of exhaust heat recovery on the heat-source low-temperature water circuit 86 side, and allows the exhaust heat recovery of the first intercooler 51 to be used to raise the temperature of the hot water, reducing the amount of heat generated by the heat source unit 81 and improving the COP.

[0151] In addition, in this embodiment, in the cascade heat recovery mode, the amount of heat and temperature recovered in the heat source high-temperature water circuit 85 are controlled by controlling at least one of the flow rate of hot water flowing to the first intercooler 51 and the flow rate of cold water flowing to the second intercooler 52 so that the heating COP of the heat source device 81 is maximized.

[0152] This allows the heating load and exhaust heat recovery to be balanced more accurately, and the energy efficiency of the carbon dioxide recovery device 1 can be further improved.

[0153] In this embodiment, the second intercooler 52 cools the gas cooled by the first intercooler 51.

[0154] As a result, the heat of the high-temperature superheated steam cooled by the first intercooler 51 is used to heat the hot water in the heat source high-temperature water circuit 85, and the heat generated when the second intercooler 52 cools the supercooled liquid after cooling by the first intercooler 51 is used to heat the cold water. Efficient heating and cooling according to the required temperature ranges can be achieved.

[0155] In this embodiment, the heat source high temperature water circuit 85 includes a hot water tank (heating heat medium tank) 83 that stores hot water, a hot water side heat source supply line (heating heat medium side heat source supply line) 221 that sends hot water from the hot water tank 83 to the heat source device 81, and a hot water side heat source return line (heating heat medium side heat source return line) 222 that returns hot water from the heat source device 81 to the hot water tank 83. The first intercooler 51a is arranged on the hot water supply line (heating heat medium side heat source return line) 112a that supplies hot water from the hot water tank 83 to the reactor 11, and the first intercooler 51b is arranged on the hot water side heat source return line (heating heat medium side heat source return line) 222.

[0156] By arranging the first intercooler 51a on the hot water supply line 112a, even when it is necessary to raise the temperature of the hot water supplied to the reactor 11 to 80°C, the heat source device 81 heats the hot water stored in the hot water tank 83 so that the temperature is maintained at around 75°C, and the first intercooler 51a raises the temperature from 75°C to 80°C. Therefore, the COP is high, and since the heating of the first intercooler 51a is performed on the reactor 11 side, heat radiation loss can be reduced. Furthermore, by arranging the first intercooler 51b on the hot water side heat source return line 222, the upper limit of the temperature rise of the heat source device 81 can be lowered from 80°C to 75°C, and the temperature of the hot water flowing from the heat source device 81 to the hot water tank 83 can be raised to around 80°C by the first intercooler 51b and stored in the hot water tank 83. The hot water tank 83 absorbs the load fluctuation of the heat source device 81 due to the fluctuation of the amount of exhaust heat recovered on the low-temperature side, and hot water of a constant temperature can be supplied to the reactor 11.

[0157] In addition, in this embodiment, the heat source low-temperature water circuit 86 includes a cold water tank (cooling heat medium tank) 82 for storing cold water, a cold water side heat source supply line (cooling heat medium side heat source supply line) 121 for sending cold water from the cold water tank 82 to the heat source device 81, a cold water side heat source return line (cooling heat medium side heat source return line) 122 for returning cold water from the heat source device 81 to the cold water tank 82, and an equipment heat recovery circuit 87 that branches off from the heat source low-temperature water circuit 86 and is connected to the inlet side of the heat source device 81 of the heat source low-temperature water circuit 86 via target equipment (vacuum pump 62, carbon dioxide recovery pump 63, second intercooler 52) for performing the adsorption process or desorption process, and returns the cold water that has recovered exhaust heat from the target equipment to the heat source device 81. The second intercooler 52a is arranged in a cold water return line (cooling heat medium return line) 111b that returns cold water from the reactor 11 to the cold water tank 82, or the second intercooler 52b is arranged in the equipment heat recovery circuit 87 as a target equipment.

[0158] By arranging the second intercooler 52a in the cold water return line 111b, the temperature of the cold water is raised before it returns to the cold water tank 82, making it possible to increase the temperature of the cold water stored in the cold water tank 82. This allows high-potential cold water (low-temperature waste heat) to be supplied to the low-temperature side of the heat source device 81, thereby reducing the temperature difference with the high-temperature side and improving the COP. Furthermore, by arranging the second intercooler 52b in the equipment heat recovery circuit 87, the coldest-temperature coolant cooled by the heat source device 81 can be supplied to the second intercooler 52b, making it possible to increase the temperature difference and therefore make the second intercooler 52b more compact.

[0159] In addition, in this embodiment, the target equipment is a vacuum pump 62 or a carbon dioxide recovery pump 63 that applies suction force to the reactor 11, and the second intercooler 52 is arranged downstream of the vacuum pump 62 or the carbon dioxide recovery pump 63 in the equipment heat recovery circuit 87.

[0160] This allows the temperature of the cold water to be raised by heat exchange in the vacuum pump 62 or the carbon dioxide recovery pump 63, and then the temperature of the cold water to be further raised by heat exchange in the second intercooler 52, thereby supplying high-quality low-temperature exhaust heat to the low-temperature side of the heat source device 81.

[0161] In the above embodiment, the first intercooler 51 and the second intercooler 52 are configured to be arranged in series in the flow paths of carbon dioxide and superheated steam, but the present invention is not limited to this configuration.

[0162] A modified example in which the positional relationship between the first intercooler 51 and the second intercooler 52 is different will be described with reference to Fig. 12. Fig. 12 is a schematic diagram of a high-temperature gas cooling mechanism using the first intercooler 51 and the second intercooler 52 according to the modified example. In the following description, the same reference numerals will be used to designate components that are common or similar to those in the above embodiment, and detailed description thereof may be omitted.

[0163] As shown in FIG. 12, the carbon dioxide line 103 of the modified example includes a first carbon dioxide line 103a, a second carbon dioxide line 103b, and a third carbon dioxide line 103c.

[0164] The first carbon dioxide line 103a is connected to the first intercooler 51. A flow rate adjustment mechanism 514 is disposed in the first carbon dioxide line 103a. The flow rate adjustment mechanism 514 has a mechanism for adjusting the flow rate of the gas containing carbon dioxide and superheated steam that flows into the first intercooler 51 through the first carbon dioxide line 103a.

[0165] The second carbon dioxide line 103b is connected to the second intercooler 52. A flow rate adjustment mechanism 524 is disposed in the second carbon dioxide line 103b. The flow rate adjustment mechanism 524 has a mechanism for adjusting the flow rate of the gas containing carbon dioxide and superheated steam that flows into the second intercooler 52 through the second carbon dioxide line 103b.

[0166] The third carbon dioxide line 103c is a bypass flow path that returns the carbon dioxide and water cooled in the first intercooler 51 to the second carbon dioxide line 103b downstream of the flow rate adjustment mechanism 524. A check valve 531 is arranged in the third carbon dioxide line 103c, which prevents the movement of carbon dioxide and water from the second carbon dioxide line 103b side to the third carbon dioxide line 103c side. The carbon dioxide and water cooled in the first intercooler 51 are also cooled in the second intercooler 52 by the third carbon dioxide line 103c.

[0167] The control device 90 can adjust the amount of gas flowing into the first intercooler 51 and the amount of gas flowing into the second intercooler 52 by controlling the flow rate adjustment mechanism 514 and the flow rate adjustment mechanism 524. The control device 90 can also adjust the amount of heat recovered by the first intercooler 51 by controlling the stop valve 512 and the flow rate adjustment mechanism 513, and can also adjust the amount of heat recovered by the second intercooler 52 by controlling the stop valve 522 and the flow rate adjustment mechanism 523.

[0168] In this modified example, when the control device 90 controls the flow rate adjustment mechanism 514 and the flow rate adjustment mechanism 524 so that gas containing carbon dioxide and superheated steam flows in parallel through the first intercooler 51 and the second intercooler 52, a mixture of superheated steam supplied from the carbon dioxide capture pump 63 via the second carbon dioxide line 103b and the supercooled liquid cooled in the first intercooler 51 is supplied to the second intercooler 52. According to the configuration of this modified example, the amount of heat supplied to the second intercooler 52 is greater than in the series configuration shown in Fig. 6 of the above embodiment, and is therefore particularly effective when there is a high demand for heat recovery in the second intercooler 52 on the low-temperature side in terms of heat load balance.

[0169] In this way, the mechanism for cooling the carbon dioxide and superheated steam can be changed as appropriate depending on the circumstances.

[0170] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications. Furthermore, the effects described in the above embodiments are merely preferred effects, and the present invention is not limited to those described in the above embodiments. [Explanation of symbols]

[0171] 1. Carbon dioxide capture device 11 Reactor 12 Adsorbent 51 First intercooler (first cooling device) 52 Second intercooler (second cooling device) 62 Vacuum pump 63 Carbon dioxide capture pump 70 Heat exchange equipment 80 Heat source circuit 81 Heat source device 82 Cold water tank (cooling heat medium tank) 83 Hot water tank (heating medium tank) 85 Heat source high temperature water circuit 86 Heat source low temperature water circuit 87 Equipment heat recovery circuit 90 Control device 111 Chilled water line (cooling heat medium line) 111a Chilled water line (cooling heat medium line) 111b Cold water return line (cooling heat medium return line) 112 Hot water line (heating medium line) 112a Hot water line (heating medium line) 112b Hot water return line (heating medium return line) 150 heater

Claims

1. a reactor having an adsorbent therein, which performs an adsorption step of drawing a gas containing carbon dioxide into the adsorbent to adsorb the carbon dioxide, and a desorption step of heating the adsorbent under a reduced pressure around the adsorbent to desorb the carbon dioxide from the adsorbent; a heat exchanger capable of supplying a heating medium to the reactor and a cooling medium to the reactor; a first cooler that cools the gas containing carbon dioxide and water vapor desorbed in the desorption step; a second cooler that cools the gas containing carbon dioxide and water vapor desorbed in the desorption step; Equipped with The heat exchange device is a heat pump type heat source device that heats the heating heat medium and cools the cooling heat medium; a heat source high-temperature water circuit that heats the heating heat medium that has heated the reactor by the heat source device and recovers exhaust heat from the first cooler by the heating heat medium; a heat source low-temperature water circuit that cools the cooling heat medium that has cooled the reactor by the heat source device and recovers exhaust heat from the second cooler by the cooling heat medium; having Carbon dioxide capture equipment.

2. a control device that controls a flow rate of the heating heat medium flowing through the first cooler and a flow rate of the cooling heat medium flowing through the second cooler based on a balance between a heating load applied to the heat-source high-temperature water circuit and an amount of exhaust heat recovered in the heat-source low-temperature water circuit, The carbon dioxide capture device according to claim 1 .

3. The control device Calculating the amount of carbon dioxide and water recovered based on ambient air conditions; calculating the heating load based on the predicted recovered amounts of carbon dioxide and water; calculating the amount of exhaust heat recovered in the heat source low-temperature water circuit based on a cooling request for a target device that performs the adsorption step or the desorption step or a cooling request for the reactor; predicting a heating COP during operation of the heat source device based on the respective temperatures of the heating heat medium and the cooling heat medium supplied to the heat source device and the heating load; When the heating COP can be improved, a first heat recovery mode in which exhaust heat is recovered by each of the first cooler and the second cooler is selected, and when the heating COP cannot be improved even when the first heat recovery mode is selected, a second heat recovery mode in which exhaust heat is recovered by the second cooler is selected. The carbon dioxide capture device according to claim 2 .

4. In the first heat recovery mode, The amount of heat and temperature recovered in the heat source high temperature water circuit are controlled by controlling at least one of the flow rate of the heating heat medium flowing to the first cooler and the flow rate of the cooling heat medium flowing to the second cooler so that the heating COP of the heat source device is maximized. The carbon dioxide capture device according to claim 3 .

5. The second cooler cools the gas cooled by the first cooler. The carbon dioxide recovery device according to any one of claims 1 to 3.

6. The heat source high temperature water circuit a heating medium tank for storing the heating medium; a heating medium-side heat source supply line for transmitting the heating medium from the heating medium tank to the heat source device; a heating medium side heat source return line that returns the heating medium from the heat source device to the heating medium tank, The first cooling machine is It is arranged in a heating medium supply line or a heating medium side heat source return line that supplies the heating medium from the heating medium tank to the reactor. The carbon dioxide recovery device according to any one of claims 1 to 3.

7. The heat source low-temperature water circuit includes: a cooling heat medium tank that stores the cooling heat medium; a cooling heat medium side heat source supply line for transmitting the cooling heat medium from the cooling heat medium tank to the heat source device; a cooling heat medium side heat source return line that returns the cooling heat medium from the heat source device to the cooling heat medium tank; an equipment heat recovery circuit that branches off from the heat-source low-temperature water circuit, passes through a target device for performing the adsorption process or the desorption process, and is connected to the inlet side of the heat-source low-temperature water circuit to the heat source device, and returns the cooling heat medium that has recovered exhaust heat from the target device to the heat source device; and The second cooling device is The target equipment is disposed in a cooling heat medium return line or an equipment heat recovery circuit that returns the cooling heat medium from the reactor to the cooling heat medium tank. The carbon dioxide recovery device according to any one of claims 1 to 3.

8. the target device is a pump that applies suction force to the reactor, The second cooling device is a heat recovery circuit for recovering heat from a heat source, the heat recovery circuit being disposed downstream of the pump; The carbon dioxide capture device according to claim 7.

9. a reactor having an adsorbent therein, which performs an adsorption step of drawing a gas containing carbon dioxide into the adsorbent to adsorb the carbon dioxide, and a desorption step of heating the adsorbent under a reduced pressure around the adsorbent to desorb the carbon dioxide from the adsorbent; a heat exchanger capable of supplying a heating medium to the reactor and a cooling medium to the reactor; a first cooler that cools the gas containing carbon dioxide and water vapor desorbed in the desorption step; a second cooler that cools the gas containing carbon dioxide and water vapor desorbed in the desorption step; A carbon dioxide capture method using a carbon dioxide capture device comprising: a heat pump type heat source device provided in the heat exchanger heats the heating medium and cools the cooling medium; the heating medium that has heated the reactor is heated by the heat source device, and exhaust heat is recovered from the first cooler by the heating medium; the cooling heat medium that has cooled the reactor is cooled by the heat source device, and exhaust heat is recovered from the second cooler by the cooling heat medium; Carbon dioxide capture methods.

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