Carbon dioxide recovery apparatus and carbon dioxide recovery method

Abstract

The present application provides a kind of about carbon dioxide recovery technology that can improve the recovery rate of carbon dioxide without reducing desorption efficiency.Carbon dioxide recovery device (1) has multiple reactors (11), carbon dioxide pipeline (103), carbon dioxide recovery pump (63) and control device (90), wherein multiple reactors (11) perform the adsorption process of adsorbing carbon dioxide and the desorption process of desorbing carbon dioxide;Carbon dioxide pipeline (103) is respectively branched and connected to reactor (11), and the desorbed carbon dioxide in the desorption process flows through;Carbon dioxide recovery pump (63) is arranged at the part where the branch part of carbon dioxide pipeline (103) converges, and the internal attraction of reactor (11) is applied by carbon dioxide pipeline (103);Control device (90) controls as follows: the internal pressure of the first reactor (11a) that is firstly executed desorption process in multiple reactors (11) and subjected to the attraction of carbon dioxide recovery pump (63) drops to a specified threshold, and the attraction of carbon dioxide recovery pump (63) also acts on the second reactor (11b) that is subsequently executed desorption process.

Description

Technical Field

[0001] This invention relates to a carbon dioxide recovery device and a carbon dioxide recovery method. Background Technology

[0002] A prior art technique is known that performs the following steps: an adsorption step in which an adsorbent material adsorbs carbon dioxide from a gas such as the atmosphere containing carbon dioxide, and a desorption step after the adsorption step in which carbon dioxide is desorbed from the adsorbent material, thereby recovering carbon dioxide. Patent Document 1 is an example document describing such a technique. Patent Document 1 describes the use of multiple reactors to recover carbon dioxide, wherein the multiple reactors include adsorption structures for adsorbing carbon dioxide.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Invention Patent Publication No. 2017-528318 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In the desorption process, carbon dioxide and water are desorbed from the adsorbent material by applying high temperature and negative pressure. However, since water desorbs before carbon dioxide, the partial pressure of carbon dioxide decreases, thus increasing the desorption rate. Conversely, in the latter half of the desorption process, less water is desorbed, and the partial pressure of carbon dioxide increases, causing the desorption rate to decrease. While a method of ending the carbon dioxide desorption process after the desorption rate decreases and transferring to the next adsorption process has been considered, this method prematurely terminates the desorption process, resulting in a reduced amount of carbon dioxide recovered per cycle unit when considering the cycle from adsorption to desorption. From the perspective of improving carbon dioxide recovery efficiency, there is room for improvement in the existing technology.

[0008] The purpose of this invention is to provide a carbon dioxide recovery device and a carbon dioxide recovery method that can improve the carbon dioxide recovery rate without reducing the desorption efficiency.

[0009] Technical solutions for solving technical problems

[0010] (1) The present invention is a carbon dioxide recovery device (e.g., carbon dioxide recovery device 1 described later), comprising multiple reactors (e.g., reactor 11 described later), a carbon dioxide pipeline (e.g., carbon dioxide pipeline 103 described later), a carbon dioxide recovery pump (e.g., carbon dioxide recovery pump 63 described later), and a control device (e.g., control device 90 described later), wherein the multiple reactors have adsorbent material (e.g., adsorbent material 12 described later) inside, performing the following steps: an adsorption step in which the adsorbent material attracts a gas containing carbon dioxide to adsorb the carbon dioxide, and an adsorption step in which the adsorbent material is heated under reduced pressure around the adsorbent material, thereby causing the carbon dioxide to be removed from the adsorbent material. A desorption process for material adsorption; carbon dioxide pipelines branching off and connected to the reactors, allowing the carbon dioxide already desorbed in the desorption process to flow through; a carbon dioxide recovery pump is disposed at the junction of the branching portions of the carbon dioxide pipelines, exerting a suction force on the interior of the reactors through the carbon dioxide pipelines; a control device controls the process such that when the internal pressure of the first reactor (e.g., the first reactor 11a described later) which first performs the desorption process and is subjected to the suction force of the carbon dioxide recovery pump drops to a predetermined threshold, the suction force of the carbon dioxide recovery pump is also applied to the second reactor (e.g., the second reactor 11b described later) which subsequently performs the desorption process.

[0011] (2) In the carbon dioxide recovery device described in (1) above, a vacuum pump (e.g., vacuum pump 62 described later) may also be provided, which depressurizes the interior of the reactor, and the control device performs the following control: the suction force of the carbon dioxide recovery pump is applied to the first reactor that is performing the desorption process, and on the other hand, in the desorption process of the second reactor, the vacuum pump is driven to depressurize the interior of the second reactor and to heat the adsorbent material, and then the suction force of the carbon dioxide recovery pump is applied to the second reactor.

[0012] (3) In the carbon dioxide recovery device described in (2) above, the control device may also perform the following control: in the desorption process of the second reactor, after the heating of the adsorbent material is performed, at the moment when the internal pressure of the second reactor rises to a preset suction start pressure value (e.g., the desorption valve opening threshold described later), the suction force of the carbon dioxide recovery pump is still applied to the second reactor.

[0013] (4) The present invention is a carbon dioxide recovery method using a carbon dioxide recovery device (e.g., carbon dioxide recovery device 1 described later), the carbon dioxide recovery device comprising multiple reactors (e.g., reactor 11 described later), carbon dioxide pipelines (e.g., carbon dioxide pipeline 103 described later), and a carbon dioxide recovery pump (e.g., carbon dioxide recovery pump 63 described later), wherein the multiple reactors have adsorbent material (e.g., adsorbent material 12 described later) inside, performing the following steps: an adsorption step in which the adsorbent material attracts a gas containing carbon dioxide to adsorb the carbon dioxide, and an adsorption step in which the adsorbent material is heated under reduced pressure around the adsorbent material, thereby causing the carbon dioxide to be adsorbed from the adsorbent material. The reactor includes a desorption process; carbon dioxide pipelines branch off and connect to the reactors, allowing the carbon dioxide desorbed in the desorption process to flow through; a carbon dioxide recovery pump is located at the junction of the branched sections of the carbon dioxide pipelines, exerting a suction force on the interior of the reactors through the carbon dioxide pipelines; the carbon dioxide recovery method involves, when the internal pressure of the first reactor (e.g., the first reactor 11a described later), which first performs the desorption process and is subjected to the suction force of the carbon dioxide recovery pump, drops to a predetermined threshold (e.g., the scavenging start pressure threshold described later), the suction force of the carbon dioxide recovery pump is also applied to the second reactor (e.g., the second reactor 11b described later) that subsequently performs the desorption process.

[0014] Invention Effects

[0015] According to the present invention, a carbon dioxide recovery apparatus and a carbon dioxide recovery method are provided that can improve the carbon dioxide recovery rate without reducing the desorption efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the structure related to the gas flow of a carbon dioxide recovery device according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram showing the structure related to the flow of liquid in the carbon dioxide recovery device of this embodiment.

[0018] Figure 3 This is a schematic diagram showing the structure related to the gas flow in the reactor of the carbon dioxide recovery device of this embodiment.

[0019] Figure 4 This is a schematic diagram showing the structure related to the flow of liquid in the reactor of the carbon dioxide recovery device of this embodiment.

[0020] Figure 5This is a graph showing the time changes in the internal pressure and the amount of carbon dioxide desorbed in each reactor when the carbon dioxide recovery device of this embodiment performs the desorption process control.

[0021] Figure 6 This is a schematic diagram illustrating the gas flow in the first reactor, which is transferred from the scavenging process to the adsorbent heating process, and in the second reactor in the adsorption process.

[0022] Figure 7 This is a schematic diagram showing the gas flow in the first reactor during high-temperature desorption and in the second reactor, which is transferred from the adsorption process to the scavenging process.

[0023] Figure 8 This diagram schematically illustrates the flow of gas in the first reactor of the desorption process and the second reactor, which is transferred from the adsorbent heating process to the high-temperature desorption process. Detailed Implementation

[0024] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0025] <Overall Structure>

[0026] Figure 1 This is a schematic diagram showing the structure related to the gas flow of the carbon dioxide recovery device 1 according to an embodiment of the present invention. Figure 2 This is a schematic diagram showing the structure related to the flow of liquid in the carbon dioxide recovery device 1 of this embodiment. Additionally, in Figure 1 The diagram of the structure related to the flow of liquid in the carbon dioxide recovery unit 1 is omitted. Figure 2 The diagram of the structure related to the gas flow of the carbon dioxide recovery device 1 is omitted.

[0027] The carbon dioxide recovery device 1 of this embodiment is applicable, for example, to direct air capture (DAC) technology, which recovers carbon dioxide from the atmosphere to reduce the concentration of carbon dioxide in the atmosphere. The carbon dioxide recovered by the carbon dioxide recovery device 1 is stored underground or reused as fuel or material.

[0028] like Figure 1 and Figure 2 As shown, the carbon dioxide recovery device 1 of this embodiment includes a reactor 10, a fan 61, a vacuum pump 62, a carbon dioxide recovery pump 63, a heat exchanger 64, a separator 65, a carbon dioxide storage tank 66, an inert gas storage tank 69, a heat exchange device 70, and a control device 90.

[0029] like Figure 1As shown, the carbon dioxide recovery device 1 has 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.

[0030] The reactor 10 is configured by arranging multiple reactors 11 side by side to adsorb carbon dioxide. In this embodiment, a total of 16 reactors 11 are arranged by arranging a pair of reactors 10 on the left and right.

[0031] Figure 3 This is a schematic diagram showing the structure related to the gas flow in the reactor 11 of the carbon dioxide recovery device 1 of this embodiment. The reactor 11 is a carbon dioxide recovery reactor equipped with an adsorption material 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.

[0032] The adsorbent material 12 is disposed inside the reactor 11 for adsorbing carbon dioxide. The adsorbent material 12 is a granular component that adsorbs carbon dioxide at low temperatures (e.g., in the range of -30°C to 50°C) and desorbs (releases) carbon dioxide at high temperatures (e.g., in the range of 50°C to 110°C) when the surrounding carbon dioxide concentration is low. Examples of such adsorbent materials 12 include solid amine adsorbent materials composed of amines supported on porous materials such as silica.

[0033] Valve 21 is an on / off valve located at the connection between the carbon dioxide recovery line 103 and the reactor 11. A carbon dioxide recovery pump 63 is installed on the carbon dioxide line 103. Valve 22 is an on / off valve located at the connection between the vacuum line 102, on which the vacuum pump 62 is installed, and the reactor 11. Valve 23 is an on / off valve located at the inlet for introducing atmosphere or the like into the reactor 11. Valve 24 is an on / off valve located at the connection between the adsorption line 101 and the reactor 11.

[0034] Valve 21, valve 22, valve 23, and valve 24 are all controlled to open and close by control device 90. Valve 21, valve 22, valve 23, and valve 24 are, for example, normally open butterfly valves.

[0035] Pressure sensor 25 measures the internal pressure of reactor 11. Carbon dioxide sensor 26 measures the carbon dioxide concentration inside reactor 11. Temperature sensor 27 measures the temperature of adsorbent material 12. The measurement information from pressure sensor 25, carbon dioxide sensor 26, and temperature sensor 27 is sent to control device 90.

[0036] return Figure 1The adsorption lines 101 and fan 61 will be described below. The adsorption lines 101 branch off and connect to each reactor 11. The fan 61 is located at the junction of the branched sections of the adsorption lines 101. Driven, the fan 61 generates a gas flow from "inlet" to "outlet" through the adsorption lines 101 to the reactors 11, thereby supplying atmospheric air into the reactors 11. At the outlet section of the adsorption lines 101, a carbon dioxide concentration sensor 611, a humidity sensor 612, and a temperature sensor 613 are installed to measure the carbon dioxide, humidity, and temperature discharged from the adsorption lines 101. The measurement information from the carbon dioxide concentration sensor 611, humidity sensor 612, and temperature sensor 613 is sent to the control device 90.

[0037] Vacuum lines 102 branch off and connect to each reactor 11. Vacuum pumps 62 are located at the junction of the branches of the vacuum lines 102. When driven, vacuum pumps 62 draw in gas from inside the reactor 11 through the vacuum lines 102, bringing the interior of the reactor 11 into a vacuum or near-vacuum state.

[0038] Carbon dioxide pipelines 103 branch off and connect to each reactor 11. At the junctions where the branches of the carbon dioxide pipelines 103 converge, a carbon dioxide recovery pump 63, a heat exchanger 64, a separator 65, and a carbon dioxide storage tank 66 are installed.

[0039] The carbon dioxide recovery pump 63 acts as an attractive force to transport carbon dioxide flowing in the carbon dioxide pipeline 103 to the carbon dioxide storage tank 66. A one-way valve 631 is installed upstream of the carbon dioxide recovery pump 63 on the carbon dioxide pipeline 103. This configuration prevents gas from flowing back from the heat exchanger 64 side to the reactor 11 side.

[0040] Heat exchanger 64 is an intercooler that cools and separates the high-temperature gas containing carbon dioxide recovered from reactor 11.

[0041] Water separated from the gas in heat exchanger 64 is recovered by separator 65. Separator 65 is equipped with a first valve 651 and a second valve 652. The first valve 651 opens and closes the path communicating with the gas phase section of separator 65. The second valve 652 opens and closes the path communicating with the liquid phase section of separator 65.

[0042] Carbon dioxide storage tank 66 stores carbon dioxide recovered through carbon dioxide pipeline 103. A storage tank valve 661 is installed upstream of the carbon dioxide storage tank 66 on the carbon dioxide pipeline 103. The storage tank valve 661 is opened and closed by a control device 90. Furthermore, various sensors, including a pressure sensor 662, a flow sensor 663, a humidity sensor 664, a temperature sensor 665, and a carbon dioxide concentration sensor 666, are installed between the storage tank valve 661 and the carbon dioxide storage tank 66 on the carbon dioxide pipeline 103.

[0043] In addition to the carbon dioxide pipeline 103, the carbon dioxide storage tank 66 is also connected to a circulation pipeline 104 that returns ballast to the carbon dioxide recovery pump 63. A flow sensor 667 is installed on the circulation pipeline 104. Furthermore, the carbon dioxide storage tank 66 is equipped with a pressure relief valve 668 that releases pressure when a specified pressure is reached.

[0044] Next, the inert gas storage tank 69 will be described. The inert gas storage tank 69 stores N2, supplied as an inert gas from the N2 cylinder 691, at a pressure above a certain level (e.g., 980 kPa). A cylinder valve 692 is provided between the inert gas storage tank 69 and the N2 cylinder 691. Furthermore, a pressure relief valve 693 is provided on the inert gas storage tank 69 to release pressure when a predetermined pressure is reached. A pressure sensor 694 is provided inside the inert gas storage tank 69. The pressure information measured by the pressure sensor 694 is sent to the control device 90.

[0045] The inert gas storage tank 69 is connected to the carbon dioxide pipeline 103 via the inert gas supply pipeline 107. An inert gas valve 695 is installed on the inert gas supply pipeline 107. The inert gas valve 695 is opened and closed by a control device 90.

[0046] Reference Figure 2 The heat exchange device 70 will now be described. During the desorption process in each reactor 11 of the reactor 10, the heat exchange device 70 supplies heat energy to heat the reactor 11 to a predetermined temperature. Additionally, the heat exchange device 70 recovers heat energy not needed during the adsorption process in each reactor 11.

[0047] The heat exchange device 70 of this embodiment includes a heat source circuit 80, a cold water pipeline 111, a warm water pipeline 112, a three-way valve 30, a bypass path 31, and a bypass valve 32.

[0048] The heat source circuit 80 is mainly composed of a heat pump type heat source 81, a cold water storage tank 82, a warm water storage tank 83, a cold water-side heat source circulation pump 821, and a warm water-side heat source circulation pump 831. Heat exchange occurs between the cooling heat medium flowing through the cold water pipeline 111 and the heating heat medium flowing through the warm water pipeline 112. Through the heat movement generated in the heat source circuit 80, the heat medium flowing through the cold water pipeline 111 is cooled, and the heat medium flowing through the warm water pipeline 112 is heated. The heat medium is, for example, a liquid such as water. Furthermore, the cold water-side heat source circulation pump 821 is disposed in the cold water circulation path connecting the heat source 81 and the cold water storage tank 82, and the warm water-side heat source circulation pump 831 is disposed in the warm water circulation path connecting the heat source 81 and the warm water storage tank 83.

[0049] The cold water pipeline 111 is a piping system for supplying cold water as a heat medium for cooling. The cold water pipeline 111 branches to connect to the upstream and downstream sides of each reactor 11, connecting the cold water storage tank 82 to each reactor 11. The pipeline connected to the upstream side of each reactor 11 is designated as the cold water supply pipeline 111a, and the pipeline connected to the downstream side of each reactor 11 is designated as the cold water return pipeline 111b.

[0050] A cold water supply line 111a is connected in parallel to multiple reactors 11, allowing cold water to be supplied to each reactor 11 in parallel. A first cold water circulation pump 822 and a second cold water circulation pump 823 are installed on the cold water supply line 111a. The first cold water circulation pump 822 and the second cold water circulation pump 823 may be cascaded pumps, for example.

[0051] Additionally, a circulation pipeline 824 is installed on the cold water supply pipeline 111a, returning from the downstream side of the second cold water circulating pump 823 to the upstream side. A safety valve 825 is installed on this circulation pipeline 824. When the pressure in the system of the second cold water circulating pump 823 and the cold water pipeline 111a reaches a certain level, the safety valve 825 releases pressure to suppress pressure rise. By arranging the safety valve 825, which releases pressure when the pressure in the cold water pipeline 111a system is abnormal, in parallel with the second cold water circulating pump 823, both the high-flow circulation and safe operation of the second cold water circulating pump 823 can be considered.

[0052] The cold water return line 111b is also connected in parallel to multiple reactors 11, and the cold water recovery after cooling can also be carried out in parallel for each reactor 11.

[0053] The warm water pipeline 112 is a piping system for the flow of warm water as a heating medium. The warm water pipeline 112 branches to connect to the upstream and downstream sides of each reactor 11, connecting the warm water storage tank 83 to each reactor 11. The pipeline connected to the upstream side of each reactor 11 is designated as the warm water supply pipeline 112a, and the pipeline connected to the downstream side of each reactor 11 is designated as the warm water return pipeline 112b.

[0054] A warm water supply line 112a is connected in parallel to multiple reactors 11, allowing the supply of warm water to each reactor 11 in parallel. A first warm water circulation pump 832 and a second warm water circulation pump 833 are installed on the warm water supply line 112a. The first warm water circulation pump 832 and the second warm water circulation pump 833 may be cascaded pumps, for example. By utilizing the cascaded pumps, which generate a large amount of heat during operation, the heat medium passing through the first warm water circulation pump 832 and the second warm water circulation pump 833 can be further heated.

[0055] Additionally, a circulation pipeline 834 is installed on the warm water supply pipeline 112a, returning from the downstream side of the second warm water circulation pump 833 to the upstream side. A safety valve 835 is installed on this circulation pipeline 834. When the pressure in the system of the second warm water circulation pump 833 and the warm water pipeline 112a reaches a certain level, the safety valve 835 releases pressure to suppress pressure rise. By arranging the safety valve 835, which releases pressure when the pressure in the warm water pipeline 112a system is abnormal, in parallel with the second warm water circulation pump 833, both the high-flow circulation and safe operation of the second warm water circulation pump 833 can be considered.

[0056] The warm water return pipeline 112b is also connected in parallel to multiple reactors 11, and the recovery of warm water after heating can also be carried out in parallel for each reactor 11.

[0057] A three-way valve 30 is connected to the cold water line 111, the warm water line 112, and the reactor 11. The three-way valve 30 is respectively disposed on the upstream side and the downstream side of the reactor 11. The three-way valve 30 is configured to select the cold water connection state between the cold water line 111 and the reactor 11, the warm water connection state between the warm water line 112 and the reactor 11, and the disconnection state of disconnecting the cold water line 111 and the warm water line 112 and the reactor 11 by switching the flow path.

[0058] The flow path switching of the three-way valve 30 is controlled by the control device 90. The hot medium is introduced into the reactor 11 through the three-way valve 30 configured on the upstream side, and the hot medium is returned to the heat source 81 side through the three-way valve 30 configured on the downstream side.

[0059] The bypass path 31 is a flow path that allows the heat medium to move between reactors 11. The bypass path 31 connects two reactors 11. The reactors 11 connected by the bypass path 31 can be adjacent reactors 11 or non-adjacent reactors 11 located in separate positions.

[0060] A bypass valve 32 is disposed in a bypass path 31. The bypass valve 32 is disposed in multiple bypass paths 31. The opening and closing of the bypass valve 32 is controlled by a control device 90.

[0061] Figure 4 This is a schematic diagram showing the structure 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 disposed on the upstream side of the reactor 11 is referred to as three-way valve 30a, and the three-way valve 30 disposed on the downstream side of the reactor 11 is referred to as three-way valve 30b.

[0062] like Figure 4 As shown, reactor 11 has an inlet-side flow path 33 connected to the inlet for the inflow of hot medium and an outlet-side flow path 34 connected to the outlet for the outflow of hot medium. A bypass path 31 is connected to the outlet-side flow path 34 of reactor 11 and to the inlet-side flow path 33 of another reactor 11.

[0063] A three-way valve 30a is installed at the upstream end of the inlet-side flow path 33, and a three-way valve 30b is also installed at the downstream end of the outlet-side flow path 34. In the warm water connection state, the three-way valve 30a is connected to the warm water supply line 112a, and the three-way valve 30b is connected to the warm 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.

[0064] Three-way valves 30a and 30b are configured to regulate flow rate. This flow rate regulation function allows for adjustment of the flow rate of warm water when connected to warm water, and also allows for adjustment of the flow rate of cold water when connected to cold water.

[0065] A temperature sensor 35 is installed on the inlet-side flow path 33. A temperature sensor 36 and a flow sensor 37 are installed on the outlet-side flow path 34. The measurement information from the temperature sensor 35, temperature sensor 36, and flow sensor 37 is sent to the control device 90.

[0066] Next, the control device 90 will be described. The control device 90 controls the operation of each part of the carbon dioxide recovery unit 1. The control device 90 controls the driving and stopping of the equipment used for carbon dioxide adsorption and desorption. In order for multiple reactors 11 to repeatedly perform adsorption and desorption in a time sequence, the control device 90 selectively controls the timing of the supply of heat medium to heat and cool each reactor 11.

[0067] 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 installed in each reactor 11, as well as the opening and closing of each bypass valve 32. Additionally, the control device 90 controls the drive of the fan 61, vacuum pump 62, carbon dioxide recovery pump 63, first cold water circulation pump 822, second cold water circulation pump 823, first warm water circulation pump 832, and second warm water circulation pump 833, controls the opening and closing of safety valves 825 and 835, and controls the heat exchange of the heat exchange device 70.

[0068] The control device 90 is, for example, a computer equipped with a CPU (Central Processing Unit), ROM (Read-Only Memory), RAM (Random Access Memory), etc. The control device 90 can be configured as a single unit or multiple units. Alternatively, the control device 90 can also be configured using electrical circuits such as relays.

[0069] <Carbon Dioxide Recovery>

[0070] Next, the control of carbon dioxide recovery via control device 90 will be explained. The carbon dioxide recovery device 1 alternately performs an adsorption process in which the adsorbent material 12 in the reactor 11 adsorbs carbon dioxide from the air or other gases, and a desorption process in which the adsorbed carbon dioxide is desorbed from the adsorbent material 12. The desorbed carbon dioxide is stored in the carbon dioxide storage tank 66, thereby removing and recovering carbon dioxide from the air.

[0071] The adsorption process involves adsorbing carbon dioxide onto the adsorbent material 12 within reactor 11. During this process, valves 23 and 24 of reactor 11 are open, while valves 21 and 22 are closed. Simultaneously with this valve opening and closing control, three-way valves 30a and 30b are connected to a cold water supply via heat exchange device 70, allowing cold water to flow within reactor 11 to cool the adsorbent material 12. Fan 61 is driven to generate a gas flow from upstream to downstream, drawing in carbon dioxide-containing gas (e.g., atmospheric air) through valve 23. The drawn-in gas passes through the adsorbent material 12 within reactor 11. At this time, the temperature inside reactor 11 is lowered to ambient temperature (25°C) by the cooling water, and the carbon dioxide in the gas is adsorbed by the adsorbent material 12. Gases other than carbon dioxide, such as nitrogen and oxygen, are discharged to the outside of the carbon dioxide recovery unit 1 through valve 24 and adsorption line 101.

[0072] The desorption process is the process of desorbing carbon dioxide from the adsorbent material 12 inside reactor 11. During the desorption process, valves 21 (first), 23 (third), and 24 (fourth) of reactor 11 are closed, while valve 22 is open. Vacuum pump 62 operates, drawing in gas from inside reactor 11 and reducing the pressure to a vacuum or near-vacuum state (purging process). Simultaneously with the valve opening and closing control, three-way valves 30a and 30b are controlled to a warm water connection state via heat exchange device 70. Warm water flows within reactor 11 to supply heat energy, causing the adsorbent material 12 in reactor 11 to heat up (adsorbent material temperature rise). Through the controlled temperature rise of adsorbent material 12, adsorbent material 12 is also heated to a sufficiently specified temperature required for the desorption process (e.g., 80°C), causing the carbon dioxide adsorbed by adsorbent material 12 to desorb (high-temperature desorption). Valve 22, valve 23 and valve 24 are closed, valve 21 is opened, and carbon dioxide recovery pump 63 is driven to store the desorbed carbon dioxide in carbon dioxide storage tank 66 through carbon dioxide pipeline 103.

[0073] <Desorption Process Control>

[0074] In this embodiment, the control device 90 uses a common carbon dioxide recovery pump 63 for multiple reactors 11, while staggering the start times of their respective desorption processes to control the desorption process in a manner that prevents them from starting at the same time. In the following description, the preceding reactor 11 refers to the reactor 11 that performs the desorption process first, and the following reactor 11 refers to the reactor 11 that performs the desorption process after the preceding reactor 11.

[0075] Reference Figure 5 The desorption process control at different times for each reactor 11 is explained. Figure 5 This is a graph showing the time changes in the internal pressure and the amount of carbon dioxide desorbed in each reactor 11 when the carbon dioxide recovery device 1 of this embodiment performs the desorption process control.

[0076] exist Figure 5 The diagram shows the pressure changes of three reactors 11: reactor 11a, reactor 11b, and reactor 11c. Reactor 11a is the first reactor 11 to perform the desorption process. Reactor 11b is the reactor 11 that performs the desorption process after reactor 11a, and is the later reactor 11 relative to reactor 11a. Reactor 11c is the reactor 11 that performs the desorption process after reactor 11b, and is the later reactor 11 relative to reactor 11b.

[0077] In order to perform desorption processes at staggered times, the control device 90 is set with a desorption valve opening threshold and a scavenging start pressure threshold.

[0078] The scavenging start pressure threshold is a set suction start pressure value based on the internal pressure (inner cylinder pressure) of the upstream reactor 11. This threshold serves as a reference for determining when to initiate the scavenging process in the desorption process of the downstream reactor 11. When the internal pressure of the upstream reactor 11 is lower than the scavenging start pressure threshold, the control device 90 initiates the scavenging process in the downstream reactor 11. When the desorption sequence is set to n, the nth reactor 11 initiates the scavenging process when the pressure inside the cylinder of the (n-1)th reactor 11 drops to a certain scavenging start pressure threshold.

[0079] The desorption valve opening threshold is a predetermined threshold set for the internal pressure (inner cylinder pressure) of the downstream reactor 11. The desorption valve opening threshold serves as a reference for determining the moment when the suction force of the carbon dioxide recovery pump 63 acts on the downstream reactor 11. When water desorption begins after the scavenging process and the internal pressure of the downstream reactor 11 exceeds the desorption valve opening threshold, the control device 90 controls the first valve 21, which serves as the desorption valve, to open and drives the carbon dioxide recovery pump 63, causing the suction force to act on the upstream reactor 11, while simultaneously causing the suction force to act on the downstream reactor 11.

[0080] Reference Figures 6-8 This explains the flow of gas in each process step. Figure 6 This diagram schematically illustrates the gas flow in the first reactor 11a, which is transferred from the scavenging process to the adsorbent material heating process, and in the second reactor 11b, which is in the adsorption process. Figure 7 This is a schematic diagram showing the flow of gas in the first reactor 11a during high-temperature desorption and in the second reactor 11b, which is transferred from the adsorption process to the scavenging process. Figure 8 This diagram schematically illustrates the gas flow in the first reactor 11a of the desorption process and in the second reactor 11b, which is transferred from the adsorbent heating process to the high-temperature desorption process. Additionally, in Figures 6-8 The diagrams of parts such as valve 23 (3rd valve) and valve 24 (4th valve) are omitted.

[0081] like Figure 6 As shown in (a), the control device 90 causes the first reactor 11a, which is the upstream stage, to perform a scavenging process, and causes the second reactor 11b, which is the downstream stage, to perform an adsorption process. Figure 6 As shown in (b), after the scavenging process, the control device 90 closes the second valve 22, causing the first reactor 11a to perform a heating process in which the adsorbent material 12 is heated to a predetermined temperature via the heat exchange device 70. On the other hand, the control device 90 causes the second reactor 11b to continue performing the adsorption process.

[0082] exist Figure 7In stage (a) shown, when the internal pressure of the first reactor 11a exceeds the desorption valve opening threshold, the control device 90 controls the first valve 21 of the first reactor 11a to open and drives the carbon dioxide recovery pump 63. Accordingly, a suction force acts on the first reactor 11a, recovering carbon dioxide to the carbon dioxide storage tank 66 via the carbon dioxide pipeline 103. During this stage, since the first valve 21 of the second reactor 11b is controlled to close, the first reactor 11a and the second reactor 11b are not connected.

[0083] exist Figure 7 In stage (b) shown, the control device 90 keeps the first valve 21 of the first reactor 11a open, continuing high-temperature desorption. On the other hand, when the internal pressure of the first reactor 11a, which is the upstream stage, drops to the scavenging start pressure threshold, the control device 90 controls the second valve 22 of the second reactor 11b, which is the downstream stage, to open and drives the vacuum pump 62. Accordingly, the second reactor 11b is transferred to the scavenging process.

[0084] exist Figure 8 In stage (a) shown in the diagram, the control device 90 keeps the first valve 21 of the first reactor 11a in the open state to continue high-temperature desorption. On the other hand, the control device 90 causes the second reactor 11b, which has undergone the scavenging process, to perform a heating process in which the adsorbent material 12 is heated to a predetermined temperature by the heat exchange device 70.

[0085] exist Figure 8 In stage (b) shown, the control device 90 keeps the first valve 21 of the first reactor 11a open, continuing high-temperature desorption. On the other hand, when the internal pressure of the second reactor 11b (which becomes the downstream stage) exceeds the desorption valve opening threshold, the control device 90 controls the first valve 21 of the second reactor 11b to open. In this stage, since the first valve 21 of the first reactor 11a is also controlled to be open, the interiors of the first reactor 11a and the second reactor 11b are connected via the carbon dioxide pipeline 103. Figure 5 As shown, the internal pressure of the first reactor 11a and the internal pressure of the second reactor 11b become equal. Consequently, the moisture-containing gas initially generated in the second reactor 11b due to the desorption process moves to the first reactor 11a. In the first reactor 11a, where the moisture-containing gas has moved, the partial pressure of carbon dioxide decreases, and the desorption efficiency increases.

[0086] In the case of the second reactor 11b as the upstream section and the third reactor 11c as the downstream section, the control device 90 performs the operation in accordance with... Figures 6-8 The controls described herein are the same as those controls. For example... Figure 5As shown, the internal pressure of the second reactor 11b and the internal pressure of the third reactor 11c become equal. Water generated first in the third reactor 11c moves to the second reactor 11b, increasing the desorption efficiency of the second reactor 11b. In this example, the internal pressure of the first reactor 11a is also equal to the internal pressures of the second reactor 11b and the third reactor 11c, and water is also supplied from the third reactor 11c to the first reactor 11a. This allows for the staggered start times of the desorption processes in the multiple reactors 11 to recover carbon dioxide. In the initial stage, the amount of carbon dioxide desorbed from the first reactor 11a gradually increases. In the next stage, carbon dioxide is recovered from the second reactor 11b in addition to the first reactor 11a, further increasing the amount of carbon dioxide desorbed. And in the next stage, carbon dioxide is recovered from the third reactor 11c in addition to the first and second reactors 11b, further increasing the amount of carbon dioxide desorbed.

[0087] As described above, the carbon dioxide recovery apparatus 1 of this embodiment includes multiple reactors 11, carbon dioxide pipelines 103, a carbon dioxide recovery pump 63, and a control device 90. Each reactor 11 contains an adsorbent material 12 and performs the following steps: an adsorption step where the adsorbent material 12 attracts carbon dioxide-containing gas to adsorb carbon dioxide, and a desorption step where the adsorbent material 12 is heated under reduced pressure to desorb carbon dioxide from it. The carbon dioxide pipelines 103 are branched and connected to the reactors 11, allowing the carbon dioxide desorbed during the desorption step to flow through them. The carbon dioxide recovery pump 63 is located at the junction of the branched portions of the carbon dioxide pipelines 103 and exerts a suction force on the interior of the reactors 11 via the carbon dioxide pipelines 103. The control device 90 performs the following control: when the internal pressure of the first reactor 11a, which first performs the desorption step and is subjected to the suction force of the carbon dioxide recovery pump 63, drops to a predetermined threshold (predetermined threshold), the suction force of the carbon dioxide recovery pump 63 is also applied to the second reactor 11b, which subsequently performs the desorption step. In addition, in this embodiment of the carbon dioxide recovery method, when the internal pressure of the first reactor 11a, which first performs the desorption process and is subjected to the attraction force of the carbon dioxide recovery pump 63, drops to a predetermined threshold (predetermined threshold), the attraction force of the carbon dioxide recovery pump 63 is also applied to the second reactor 11b, which subsequently performs the desorption process.

[0088] By configuring the carbon dioxide recovery device 1 and carbon dioxide recovery method in this way, when n is a natural number, at the moment when the pressure inside the (n-1)th reactor 11 (as the second reactor 11b in the subsequent stage) drops below a certain value, the desorption process begins in the nth reactor 11 (as the first reactor 11a in the preceding stage) in the desorption sequence. Because the carbon dioxide recovery pump 63 shared by multiple reactors 11 prevents them from starting desorption at different times, even if the (n-1)th reactor 11 stops desorbing water in the latter half of the desorption process, the water generated first in the nth reactor 11 at the start of the desorption process will move to the (n-1)th reactor 11 in the same system. The water moving to the interior of the (n-1)th reactor 11 in the latter half of the desorption process causes a decrease in the partial pressure of carbon dioxide, thereby increasing the desorption rate. Furthermore, by maintaining the inlet pressure of the carbon dioxide recovery pump 63 above a certain level, although no carbon dioxide is recovered, the time required to maintain a vacuum inside the reactor 11 can be reduced, thereby improving the carbon dioxide recovery efficiency relative to the power of the carbon dioxide recovery pump 63. Thus, based on the structure of this embodiment, a carbon dioxide recovery device 1 and a carbon dioxide recovery method can be realized that can improve the carbon dioxide recovery rate without reducing the desorption efficiency.

[0089] In addition, the carbon dioxide recovery device 1 of this embodiment also includes a vacuum pump 62, which depressurizes the interior of the reactor 11. The control device 90 performs the following control: the suction force of the carbon dioxide recovery pump 63 is applied to the first reactor 11a, which is performing the desorption process; on the other hand, in the desorption process of the second reactor 11b, the vacuum pump 62 is driven to depressurize the interior of the second reactor 11b; and after the adsorbent material 12 is heated, the suction force of the carbon dioxide recovery pump 63 is still applied to the second reactor 11b.

[0090] Therefore, after the water begins to desorb after depressurization and heating, the interior of the first reactor 11a and the interior of the second reactor 11b can be reliably kept in communication.

[0091] In addition, in this embodiment, the control device 90 performs the following control: in the desorption process of the second reactor 11b, after the adsorbent material 12 is heated, at the moment when the internal pressure of the second reactor 11b rises to the preset desorption valve opening threshold (attraction start pressure value), the suction force of the carbon dioxide recovery pump 63 is still applied to the second reactor 11b.

[0092] Accordingly, since the carbon dioxide recovery pump 63 acts on the second reactor 11b at the moment when water begins to desorb, the moment when water moves towards the first reactor 11a can be advanced, thereby further improving the desorption efficiency.

[0093] The embodiments of the present invention have been described above, but are not limited to the embodiments or modifications described above. Furthermore, the effects described in the above embodiments are merely preferred examples and are not limited to the effects described in the above embodiments.

[0094] Explanation of reference numerals in the attached figures

[0095] 1: Carbon dioxide recovery device; 11: Reactor; 12: Adsorbent material; 62: Vacuum pump; 63: Carbon dioxide recovery pump; 64: Heat exchanger; 65: Separator; 70: Heat exchange device; 90: Control device; 102: Vacuum line; 103: Carbon dioxide line.

Claims

1. A carbon dioxide recovery device, characterized in that, It is equipped with multiple reactors, carbon dioxide pipelines, carbon dioxide recovery pumps, and control devices, among which, The reactors contain adsorbent material and perform the following steps: an adsorption step in which the adsorbent material attracts a gas containing carbon dioxide to adsorb the carbon dioxide, and a desorption step in which the carbon dioxide is desorbed from the adsorbent material by heating the adsorbent material under reduced pressure. The carbon dioxide pipelines are branched and connected to the reactor, and are used to allow the carbon dioxide that has been desorbed in the desorption process to flow through. The carbon dioxide recovery pump is located at the junction of the branch sections of the carbon dioxide pipeline, and exerts a suction force on the interior of the reactor through the carbon dioxide pipeline. The control device performs the following control: when the internal pressure of the first reactor, which is the first to perform the desorption process among the plurality of reactors and is attracted by the carbon dioxide recovery pump, drops to a predetermined threshold, the attractive force of the carbon dioxide recovery pump is also applied to the second reactor, which subsequently performs the desorption process.

2. The carbon dioxide recovery device according to claim 1, characterized in that, It also includes a vacuum pump that reduces the pressure inside the reactor. The control device performs the following controls: The carbon dioxide recovery pump applies suction force to the first reactor, which is performing the desorption process. On the other hand, in the desorption process of the second reactor, the vacuum pump is driven to depressurize the interior of the second reactor and to heat the adsorbent material. Afterward, the suction force of the carbon dioxide recovery pump also applies to the second reactor.

3. The carbon dioxide recovery device according to claim 2, characterized in that, The control device performs the following controls: In the desorption process of the second reactor, after the adsorbent material is heated, when the internal pressure of the second reactor rises to a preset suction start pressure value, the suction force of the carbon dioxide recovery pump is still applied to the second reactor.

4. A method for recovering carbon dioxide, wherein the method uses a carbon dioxide recovery device, wherein... The carbon dioxide recovery device includes multiple reactors, carbon dioxide pipelines, and carbon dioxide recovery pumps, wherein... The reactors contain adsorbent material and perform the following steps: an adsorption step in which the adsorbent material attracts a gas containing carbon dioxide to adsorb the carbon dioxide, and a desorption step in which the carbon dioxide is desorbed from the adsorbent material by heating the adsorbent material under reduced pressure. The carbon dioxide pipelines are branched and connected to the reactor, and are used to allow the carbon dioxide that has been desorbed in the desorption process to flow through. The carbon dioxide recovery pump is located at the junction of the branch sections of the carbon dioxide pipeline, and exerts a suction force on the interior of the reactor through the carbon dioxide pipeline. The carbon dioxide recovery method is characterized in that, when the internal pressure of the first reactor, which is first subjected to the desorption process and is attracted by the carbon dioxide recovery pump, drops to a predetermined threshold, the attractive force of the carbon dioxide recovery pump is also applied to the second reactor, which subsequently performs the desorption process.

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