Carbon dioxide recovery device

Abstract

This carbon dioxide recovery device comprises: a plurality of modules that adsorb carbon dioxide; a heat exchange device which has a heat source device, a high-temperature water tank that retains high-temperature water, and a low-temperature water tank that retains low-temperature water; a bypass path; a bypass valve; and a control unit. Before executing a cooling step for cooling a first module during an adsorption step of a second module, the control unit executes a first pre-cooling step for supplying the low-temperature water from the low-temperature water tank to the first module when the difference obtained by subtracting the temperature of the module from the temperature of the low-temperature water is smaller than a first temperature condition, and executes a second pre-cooling step for supplying the low-temperature water from the second module to the first module by opening the bypass valve when the difference obtained by subtracting the temperature of the module from the temperature of the low-temperature water is larger than the first temperature condition.

Description

Carbon dioxide capture device

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

[0002] Efforts to mitigate or reduce the impact of climate change have been ongoing, and research and development on carbon dioxide capture devices are being conducted to achieve this. Furthermore, technologies that utilize heat sources such as heat pumps in systems that heat or cool target equipment using a heat transfer medium are known. Patent document 1, for example, describes this type of technology. Patent document 1 discloses a technology that monitors the temperature of a reactor in the preheating process and controls the flow of water.

[0003] Japanese Patent Publication No. 2021-090895

[0004] In carbon dioxide recovery devices, which use a module with an adsorbent to draw in a gas such as air containing carbon dioxide, adsorb the carbon dioxide onto the adsorbent, and then heat the adsorbent to desorb the adsorbed carbon dioxide and recover it, heat sources such as heat pumps are also used.

[0005] In carbon dioxide capture systems, a high-temperature heating medium is supplied to the adsorption module for the desorption process, while a low-temperature cooling medium is supplied for the cooling process, which involves condensing waste heat from each component and the recovered water vapor. These adsorption and desorption processes are performed alternately. Therefore, in order to perform the adsorption process on a module heated in the desorption process, it is necessary to supply a cooling medium to pre-cool the module. If the difference between the temperature of the supplied cooling medium and the module's pre-cooled temperature is small, the pre-cooling time will be prolonged. When there are multiple modules, the pre-cooling process must be completed according to the module with the longest pre-cooling time before the adsorption process begins, which reduces the overall cycle efficiency of the system and is undesirable. Furthermore, there has been a need to enable efficient heat use in the heating and cooling return cycles and reduce energy consumption.

[0006] The present invention aims to provide a carbon dioxide capture device that can shorten the overall pre-cooling time and shorten the cycle between the desorption and adsorption processes, thereby improving energy efficiency. Ultimately, this will contribute to mitigating or reducing the impact of climate change.

[0007] (1) A carbon dioxide recovery device according to one aspect of the present invention (for example, carbon dioxide recovery device 1 described later) has an adsorbent (for example, adsorbent 11 described later) inside and comprises a plurality of modules (for example, modules 2A, modules 2B described later) that perform an adsorption step of drawing a gas containing carbon dioxide onto the adsorbent to adsorb the carbon dioxide and a desorption step of heating the area around the adsorbent to desorb the carbon dioxide from the adsorbent, a heat pump type heat source (for example, heat source 21 described later) that heats a high-temperature heat transfer medium (for example, high-temperature water described later) and cools a low-temperature heat transfer medium (for example, low-temperature water described later), a high-temperature heat transfer medium tank (for example, high-temperature water tank described later) that stores the high-temperature heat transfer medium heated by the heat source, and a storage unit for the low-temperature heat transfer medium cooled by the heat source The module has a low-temperature heat transfer tank (for example, a low-temperature water tank 22 described later), and a heat exchanger (for example, a heat exchanger 3 described later) that performs a heating step of supplying the high-temperature heat transfer to heat the module and a cooling step of supplying the low-temperature heat transfer to cool the module, an inlet-side flow path (for example, an inlet-side flow path 13A described later) that supplies the low-temperature heat transfer to a first module (for example, a module 2A described later) among the plurality of modules, and a bypass path (for example, a bypass path 71 described later) that connects the inlet-side flow path (for example, an inlet-side flow path 13A described later) and the outlet-side flow path (for example, an outlet-side flow path 14B described later) from which the low-temperature heat transfer flows out of a second module (for example, a module 2B described later), a bypass valve (for example, a bypass valve 74 described later) provided in the bypass path, and a control unit (for example, a control unit 4 described later), wherein the control unit, before performing the cooling step of the first module during the adsorption step of the second module, sets the temperature of the low-temperature heat transfer in the low-temperature heat transfer tank (T ＬＴ ) from the temperature (T) of the gas drawn into the second module ｏｕｔWhen the difference obtained by subtracting (the temperature of the gas sucked into the second module from the temperature of the low-temperature heat medium in the low-temperature heat medium tank) is smaller than the first temperature condition (T1), performing a first precooling step (step S21) of closing the bypass valve and supplying the low-temperature heat medium from the low-temperature heat medium tank to the first module; and when the difference obtained by subtracting the temperature of the gas sucked into the second module from the temperature of the low-temperature heat medium in the low-temperature heat medium tank is larger than the first temperature condition, performing either a second precooling step (step S22) of opening the bypass valve and supplying the low-temperature heat medium from the second module to the first module via the bypass path, or the first precooling step (step S21).

[0008] In this configuration, the precooling step for the first module is performed before executing the cooling step (adsorption step) of the first module. At this time, the temperature of the low-temperature heat medium in the low-temperature heat medium tank (T ＬＴ ) minus the temperature of the gas sucked into the second module (T ｏｕｔ ) When the difference is smaller than the first temperature condition (T1), the first precooling step is performed. Here, the first precooling step is a step of cooling the temperature of the first module from the temperature in the desorption step to a temperature close to the temperature at which the adsorption step can be performed. In the precooling for the first module, when a low-temperature heat medium having a low temperature (T ＬＴ ) is supplied to the first module, the cooling efficiency is high and the precooling time can be shortened. However, when a low-temperature heat medium having a high temperature (T ＬＴ ) is supplied to the first module, or when the exhaust heat environment temperature (outside air temperature) is high and the temperature (T ＬＴ ) is too close to the precooling completion temperature, the precooling time becomes long. The precooling completion temperature is not changed because it results from the conditions in the adsorption step. In addition, the exhaust heat environment temperature (outside air temperature) may fluctuate due to seasonal factors. For this reason, as the precooling step for the first module, it is conceivable to conduct the low-temperature heat medium to the second module first to release heat to the outside to cool the low-temperature heat medium, then flow the low-temperature heat medium after the temperature is lowered from the bypass path to the first module to cool the first module. This is the second precooling step. However, the temperature of the low-temperature heat medium (T ＬＴ ) minus the temperature of the gas sucked into the second module (T ｏｕｔIf the difference obtained by subtracting ) is smaller than the first temperature condition (T1), then the temperature of the low-temperature heat transfer medium (T ＬＴ ) is the temperature of the gas (T ｏｕｔ The temperature (T) is too close to the point where heat dissipation to the outside in the second module is impractical. For this reason, in the first pre-cooling process, the low-temperature heat transfer medium is supplied from the low-temperature heat transfer medium tank to the first module and returned from the first module to the low-temperature heat transfer medium tank. At this time, the second module may be supplied with heat transfer medium from the heat transfer medium tank without being affected by the pre-cooling of the first module. On the other hand, the temperature (T) of the low-temperature heat transfer medium is too close to the point where heat dissipation to the outside in the second module is impractical. ＬＴ The temperature (T) of the gas drawn into the second module from ) ｏｕｔ If the difference obtained by subtracting () is greater than the first temperature condition (T1), a second pre-cooling process is performed. In the second pre-cooling process, before supplying the low-temperature heat transfer medium from the low-temperature heat transfer medium tank to the first module, the low-temperature heat transfer medium is passed through the second module to release heat to the outside and lower the temperature of the low-temperature heat transfer medium. After that, the low-temperature heat transfer medium, whose temperature has cooled sufficiently, is flowed to the first module via a bypass path to cool it, thereby shortening the cooling time of the first module. In the second pre-cooling process, if there is excess waste heat from the low-temperature heat transfer medium tank, the pre-cooling of the first module can be performed sufficiently quickly to shorten the pre-cooling time, and the heat can be discharged to the outside using the second module. In contrast, in the first pre-cooling process, when pre-cooling the first module, the waste heat from the first module is used as a heat source for the heat source unit and is not sent to the second module. This reduces the energy consumption of the heat exchanger. This suppresses variations in pre-cooling time among multiple modules. Furthermore, the temperature (T) of the gas drawn into the first module ｏｕｔ ) and the temperature (T) of the gas drawn into the second module. ｏｕｔ The temperature of the first module and the ambient temperature of the external heat dissipation environment during the cooling process of the second module can be the same. In the second pre-cooling process, if too much heat is dissipated into the outside air, there will be insufficient heat dissipation on the low-temperature side, so it is important to suppress this and maintain a thermal balance between the first module and the second module.

[0009] (2) In the carbon dioxide recovery apparatus described in (1) above, the control unit performs a pre-cooling preparation step (step S00) in advance, in which it measures the pre-cooling time required to pre-cool each of the plurality of modules from the temperature of the desorption step to the temperature of the adsorption step, and calculates an average pre-cooling time (tM), which is the average of these values. The control unit can, before executing the cooling step of the first module (2A) during the adsorption step of the second module, if there is a module among the plurality of modules whose pre-cooling time is longer than the average pre-cooling time (tM), it can perform the second pre-cooling step with the module whose pre-cooling time (tA) is longer as the first module. If there is no module whose pre-cooling time is longer than the average pre-cooling time, it can perform the first pre-cooling step.

[0010] In this configuration, by measuring the pre-cooling time in advance, it is possible to identify modules whose pre-cooling time (tA) is longer than the average pre-cooling time (tM) among multiple modules of the carbon dioxide capture device. This is due to individual differences in each unit, mostly caused during manufacturing, such as variations in the flow velocity of the heat transfer medium in each module and differences in flow resistance. In these modules with longer pre-cooling times (tA), a second pre-cooling process is performed to further lower the temperature of the low-temperature heat transfer medium supplied to that module in order to shorten the pre-cooling time. In other words, among multiple modules, modules that would otherwise have long pre-cooling times and thus extend the overall cycle time are selected, and a second pre-cooling process with high pre-cooling efficiency is performed to shorten the pre-cooling time in those modules. This shortens the time until all modules have completed the pre-cooling process and moved on to the next process simultaneously. Therefore, the overall cycle time can be shortened, the efficiency of the device cycle can be improved, and energy consumption can be made more efficient. Furthermore, since the second pre-cooling process is performed after determining whether heat can be discharged from the second module, it is possible to suppress variations in pre-cooling times among multiple modules. Furthermore, by selectively performing the second pre-cooling process on only some modules, it is possible to prevent a shortage of heat sources on the low-temperature side of the heat exchanger. This allows for excess waste heat from the low-temperature side, thereby reducing energy consumption. In other words, when shortening the pre-cooling time in the relevant modules by using a cooler heat transfer medium through a bypass path, the number of modules subject to the second pre-cooling process can be appropriately set to optimize the thermal balance and control the second pre-cooling process, preventing an excessive increase in heat dissipation. This improves the energy efficiency related to pre-cooling.

[0011] (3) In the carbon dioxide recovery apparatus described in (2) above, the control unit may, before performing the cooling step of the first module during the adsorption step of the second module, perform the second pre-cooling step (step S22) if the temperature of the low-temperature heat transfer medium in the low-temperature heat transfer medium tank is higher than the second temperature condition (T2), and perform the first pre-cooling step (step S21) if the temperature of the low-temperature heat transfer medium in the low-temperature heat transfer medium tank is lower than the second temperature condition.

[0012] In this configuration, the first module, which has a long pre-cooling time (tA), can create cold water at a lower temperature than the cold water tank by passing water through it while the second module is adsorbing. This cold water can then be flowed from the second module to the first module, which is connected via a bypass path, thereby shortening the pre-cooling time. This shortens the pre-cooling process and thus shortens the overall cycle schedule. At this time, the temperature of the cold water (TA) fluctuates depending on the ambient temperature and the operating conditions of the equipment. ＬＴ By comparing the temperature of the fluctuating cold water (T2) with the threshold temperature condition (T2), it is selected whether or not it is possible to connect the second module to the first module. In other words, it is determined whether there is excess waste heat from the cold side line connected to the cold heat transfer tank and whether the waste heat ambient temperature (outside temperature) is at a value that allows pre-cooling via the bypass path. Subsequently, modules that require a long pre-cooling time can be selected to perform the second pre-cooling process (step S22), and the other modules can be selected to perform the first pre-cooling process (step S21). This allows for the adjustment of the temperature of the fluctuating cold water (T2). ＬＴ Even if a second pre-cooling process is performed, it is possible to determine that the pre-cooling time will not be prolonged, and the time until the pre-cooling process is completed in all modules and they move on to the next process simultaneously can be shortened.

[0013] (4) In the carbon dioxide recovery apparatus described in (3) above, the control unit may perform the cooling step of the first module after performing the first pre-cooling step or the second pre-cooling step.

[0014] This configuration prevents the overall pre-cooling time of the carbon dioxide capture system from being extended, allowing all modules to reach the target pre-cooling temperature when the pre-cooling process is complete. This enables all modules to start the absorption process simultaneously. As a result, the desorption and adsorption cycle is shortened, reducing energy consumption in the carbon dioxide capture system.

[0015] According to the present invention, it is possible to suppress variations in pre-cooling time among multiple modules in a carbon dioxide capture device, thereby shortening and improving the efficiency of the carbon dioxide capture device cycle.

[0016] This is a schematic diagram showing a heat exchanger equipped with a low-temperature heat transfer medium pre-cooling switching mechanism in a carbon dioxide recovery device according to an embodiment of the present invention. This is a flowchart showing the temperature control of the low-temperature heat transfer medium pre-cooling switching mechanism in a carbon dioxide recovery device according to an embodiment of the present invention.

[0017] <Embodiments> Embodiments of the present invention will be described below with reference to the drawings. In the following description, corresponding components will be denoted by the same reference numerals, and descriptions of overlapping parts may be omitted.

[0018] Figure 1 is a schematic diagram showing the configuration of a heat exchanger equipped with a low-temperature heat transfer medium pre-cooling switching mechanism in a carbon dioxide recovery device according to this embodiment. In the figure, reference numeral 1 denotes the carbon dioxide recovery device. The carbon dioxide recovery device 1 is applied, for example, to direct air capture technology (DAC) that recovers carbon dioxide from the atmosphere in order to reduce the carbon dioxide concentration in the atmosphere. The carbon dioxide recovered by the carbon dioxide recovery device 1 is stored underground or reused as fuel or material.

[0019] As shown in Figure 1, the carbon dioxide recovery device 1 comprises a module 2, a heat exchanger 3, a control unit 4, a storage unit 5, and a low-temperature water pre-cooling switching mechanism (low-temperature heat transfer medium pre-cooling switching mechanism) 6.

[0020] Module 2 is a carbon dioxide recovery module comprising an adsorbent 11 for adsorbing carbon dioxide and a temperature sensor 12 for measuring the temperature of Module 2. Multiple Module 2s are connected in parallel to the heat exchanger 3. Although the subscripts of the symbols are changed for distinction, Module 2A, Module 2B, and others have equivalent configurations. The symbols in each configuration are indicated by the subscripts A, B, C, etc., to indicate that they are configurations of that particular module.

[0021] The adsorbent 11 is placed inside the module 2 to adsorb carbon dioxide. The adsorbent 11 is a particulate material that adsorbs carbon dioxide at low temperatures (for example, in the range of -30°C to 50°C) and desorbs (releases) carbon dioxide at high temperatures (for example, in the range of 50°C to 110°C) and when the ambient carbon dioxide concentration is low. Examples of such an adsorbent 11 include solid amine carbon dioxide adsorbents composed of amines supported on a porous material such as silica.

[0022] The temperature sensor 12 in module 2 measures the temperature of the adsorbent 11. The measurement information from the temperature sensor 12 is transmitted to the control unit 4. Module 2 includes an inlet-side flow path 13 connected to an inlet through which the heat transfer medium flows in, and an outlet-side flow path 14 connected to an outlet through which the heat transfer medium flows out. The heat transfer medium circulates with the heat exchanger 3, which will be described later, to heat and cool module 2.

[0023] The heat exchanger 3 supplies thermal energy to heat the inside of module 2 to a predetermined temperature when module 2 performs a desorption process (heating process). The heat exchanger 3 also recovers unnecessary thermal energy when each module 2 performs an adsorption process. The heat exchanger 3 of this embodiment includes a heat source circuit 20, a low-temperature water line 30 (low-temperature heat transfer medium line), a high-temperature water line 40 (high-temperature heat transfer medium line), a three-way valve 50, a bypass path 71, and a bypass valve 74.

[0024] The heat source circuit 20 includes a heat source 21, a low-temperature water tank 22 (low-temperature heat transfer medium tank), a high-temperature water tank 23 (high-temperature heat transfer medium tank), a heat source low-temperature water line 24 (heat source low-temperature heat transfer medium line), and a heat source high-temperature water line 25 (heat source high-temperature heat transfer medium line).

[0025] The heat source 21 is a heat pump type heat source that cools the low-temperature heat transfer medium (heat transfer medium) and heats the high-temperature heat transfer medium (heat transfer medium). The heat source 21 uses the cooling and heating generated by compressing and expanding gas in the heat pump to cool the low-temperature heat transfer medium flowing between it and the low-temperature water tank 22, and to heat the high-temperature heat transfer medium flowing between it and the high-temperature water tank 23. The heat transfer medium is, for example, a liquid such as water.

[0026] The low-temperature water tank 22 stores the low-temperature heat transfer medium cooled by the heat source 21. The high-temperature water tank 23 stores the high-temperature heat transfer medium heated by the heat source 21. The low-temperature water tank 22 is equipped with a temperature sensor 27. The temperature sensor 27 measures the temperature of the low-temperature heat transfer medium stored in the low-temperature water tank 22. The measurement information from the temperature sensor 27 is transmitted to the control unit 4.

[0027] The heat source low-temperature water line 24 is piping for circulating low-temperature water as a low-temperature heat transfer medium between the low-temperature water tank 22 and the heat source unit 21. Although not shown in the figures, the heat source low-temperature water line 24 is equipped with a circulating water pump for pressurizing the low-temperature water. This circulating water pump can circulate high-temperature water between the high-temperature water tank 23 and the heat source unit 21. This circulating water pump may be, for example, a centrifugal pump.

[0028] The heat source high-temperature water line 25 is piping for circulating high-temperature water as a high-temperature heat transfer medium between the high-temperature water tank 23 and the heat source unit 21. Although not shown in the figures, the heat source high-temperature water line 25 is equipped with a circulating water pump for pressurizing the high-temperature water. This circulating water pump allows the high-temperature water to be circulated between the high-temperature water tank 23 and the heat source unit 21. This circulating water pump may be, for example, a centrifugal pump.

[0029] The cold water line 30 is a pipe through which cold water flows. The cold water line 30 branches and connects to the upstream and downstream sides of module 2, connecting the cold water tank 22 and module 2. Of the cold water line 30, the line connected to the inlet channel 13 located upstream of module 2 is designated as the cold water supply line 31, and the line connected to the outlet channel 14 located downstream of module 2 is designated as the cold water return line 32.

[0030] Although not shown in the diagram, a circulating water pump is located in the low-temperature water supply line 31. This circulating water pump flows low-temperature water from the low-temperature water tank 22 towards module 2. For example, a cascade pump is used for this circulating water pump.

[0031] The high-temperature water line 40 is a pipe through which high-temperature water flows. The high-temperature water line 40 branches and connects to the upstream and downstream sides of module 2, connecting the high-temperature water tank 23 and module 2. Of the high-temperature water line 40, the line connected to the inlet channel 13 located upstream of module 2 is designated as the high-temperature water supply line 41, and the line connected to the outlet channel 14 located downstream of module 2 is designated as the high-temperature water return line 42.

[0032] Although not shown in the diagram, a circulating water pump, for example, is located in the high-temperature water supply line 41. This circulating water pump flows high-temperature water from the high-temperature water tank 23 towards module 2. For example, a cascade pump is used for this circulating water pump. By using a cascade pump, which generates a large amount of heat when driven, the high-temperature water (heat transfer medium) passing through the circulating water pump can be further heated.

[0033] The three-way valve 50 is connected to the low-temperature water line 30, the high-temperature water line 40, and the module 2. The three-way valve 50 is positioned on both the upstream and downstream sides of the module 2. The three-way valve 50 is configured to allow selection by flow path switching between a low-temperature water connection state, where the module 2 is connected only to the low-temperature water line 30; a high-temperature water connection state, where the module 2 is connected only to the high-temperature water line 40; and a disconnection state, where the connection between the low-temperature water line 30 and the high-temperature water line 40 and the module 2 is cut off.

[0034] The flow path switching of the three-way valve 50 is controlled by the control unit 4. A heat transfer medium is introduced into module 2 through the three-way valve 50 located on the upstream side, and the heat transfer medium is returned from module 2 to the heat source 21 side through the three-way valve 50 located on the downstream side. In the following description, the three-way valve 50 located on the upstream side of module 2 will be referred to as three-way valve 50a, and the three-way valve 50 located on the downstream side of module 2 will be referred to as three-way valve 50b.

[0035] A three-way valve 50a is positioned at the upstream end of the inlet-side flow path 13, and a three-way valve 50b is also positioned at the downstream end of the outlet-side flow path 14. When high-temperature water is connected, the three-way valve 50a is connected to the high-temperature water supply line 41, and the three-way valve 50b is connected to the high-temperature water return line 42. When low-temperature water is connected, the three-way valve 50a is connected to the low-temperature water supply line 31, and the three-way valve 50b is connected to the low-temperature water return line 32.

[0036] The three-way valves 50a and 50b are configured to allow for flow rate adjustment. This flow rate adjustment function allows for adjustment of the flow rate of high-temperature water when connected to high-temperature water, and adjustment of the flow rate of low-temperature water when connected to low-temperature water.

[0037] The bypass path 71 is a flow path that allows the movement of the heat transfer medium between modules 2. The bypass path 7 connects two modules 2. The modules 2 connected by the bypass path 71 may be adjacent modules or modules 2 located at a distance from each other. The bypass path 71 connects the inlet flow path 13A of module 2A and the outlet flow path 14B of module 2B.

[0038] The bypass valve 74 is located in the bypass path 71. The bypass valve 74 is located in each of the multiple bypass paths 71. The bypass valve 74 is controlled to open and close by the control unit 4. The movement of the heat transfer medium in the bypass path 71 can be controlled by the three-way valves 50a and 50b in the module 2 to which the bypass path 71 is connected, and by the bypass valve 74. The bypass path 71, the bypass valve 74, and the three-way valve 50 constitute a low-temperature water pre-cooling switching mechanism (low-temperature heat transfer medium pre-cooling switching mechanism) 7.

[0039] In the low-temperature water pre-cooling switching mechanism 7, for example, when the three-way valve 50Ba of module 2B connects the low-temperature water supply line 31 and the inlet-side flow path 13B, and the three-way valve 50Bb is closed to block the low-temperature water double line 32 and the outlet-side flow path 14B, and the bypass valve 74 is open, and the three-way valve 50Aa of module 2A is closed, and the three-way valve 50Ab connects the low-temperature water double line 32 and the outlet-side flow path 14A, the low-temperature water supplied from the low-temperature water tank 22 via the low-temperature water supply line 31 flows through module 2B, through the bypass path 71 to module 2A, and then returns to the low-temperature water tank 22 via the low-temperature water double line 32.

[0040] In the low-temperature water pre-cooling switching mechanism 7, for example, when the bypass valve 74 is closed, and the three-way valve 50Aa of module 2A connects the low-temperature water supply line 31 to the inlet-side flow path 13A, and the three-way valve 50Ab connects the low-temperature water double line 32 to the outlet-side flow path 14A, the low-temperature water supplied from the low-temperature water tank 22 via the low-temperature water supply line 31 flows to module 2A, and then returns to the low-temperature water tank 22 via the low-temperature water double line 32. In this case, module 2B can also supply low-temperature water in parallel with module 2A. Alternatively, module 2B can supply or stop low-temperature water independently of module 2A.

[0041] The low-temperature water pre-cooling switching mechanism 7 may be further configured such that modules 2A and 2B are connected to other modules 2C to 2E. For example, the bypass path 71 may be configured to connect the inlet flow path 13B of module 2B to the outlet flow path 14C of module 2C. The bypass path 71 may be configured to connect the inlet flow path 13C of module 2C to the outlet flow path 14D of module 2D. The bypass path 71 may be configured to connect the inlet flow path 13D of module 2D to the outlet flow path 14E of module 2E. The bypass path 71 may be configured to connect the inlet flow path 13E of module 2E to the outlet flow path 14A of module 2A.

[0042] The control unit 4 controls the operation of each part of the carbon dioxide capture device 1. The control unit 4 controls the operation of devices used for carbon dioxide adsorption and desorption in module 2, such as driving and stopping. The control unit 4 selectively controls the timing of supplying the heat transfer medium to module 2 to provide heating and cooling to module 2 so that module 2 repeatedly performs adsorption and desorption in a time series. The control unit 4 controls the operation of the low-temperature water pre-cooling switching mechanism 7 to enable the movement of the heat transfer medium between multiple modules 2.

[0043] Devices controlled by the control unit 4 include the aforementioned heat source 21, three-way valve 50, and circulating water pump (not shown). Although not shown, devices controlled by the control unit 4 also include valves for opening and closing piping to introduce and discharge gases such as air to and from module 2, a flow fan for circulating gases such as air through piping in module 2, a vacuum pump for reducing the pressure inside module 2 to desorb carbon dioxide from the adsorbent 11, valves for opening and closing piping to discharge and recover carbon dioxide from module 2, a recovery pump for recovering carbon dioxide discharged from module 2, and a desorbed water condenser (intercooler) for separating water discharged along with carbon dioxide from carbon dioxide.

[0044] The control unit 4 is, for example, a computer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The control unit 4 may consist of one unit or multiple units. The control unit 4 may also be configured using electrical circuits such as relays.

[0045] In the carbon dioxide recovery device 1, the cold water stored in the cold water tank 22 is supplied to module 2 (adsorbent 11). The cold water stored in the cold water tank 22 is also supplied to the auxiliary equipment 61 and used to cool these auxiliary equipment 61.

[0046] The memory unit 5 stores the temperature conditions, which will be described later. The temperature conditions are read out by the control unit 4 during the adsorption process (cooling process), the first pre-cooling process, the second pre-cooling process, etc. Examples of temperature conditions include the first temperature condition T1 and the second temperature condition T2. ​​Details of these will be described later.

[0047] <Carbon Dioxide Recovery> Next, the control by the control unit 4 for carbon dioxide recovery will be explained. The carbon dioxide recovery device 1 alternately performs an adsorption process in which gas such as the outside atmosphere is drawn into the adsorbent material 11 in the module 2 and carbon dioxide in the gas is adsorbed, and a desorption process in which carbon dioxide adsorbed on the adsorbent material 11 is desorbed. The desorbed carbon dioxide is stored in a carbon dioxide tank (not shown), thereby removing and recovering carbon dioxide from the air.

[0048] The adsorption process involves adsorbing carbon dioxide onto the adsorbent material 11 within module 2. During the adsorption process, the control unit 4 controls the three-way valves 50a and 50b of the heat exchanger 3 to a low-temperature water connection state, and the low-temperature water flows through module 2 to cool the adsorbent material 11 within module 2. The adsorption process also serves as a cooling process for module 2. The adsorption process also serves as a heat absorption process for the low-temperature water. The control unit 4 operates a circulation fan (not shown) to draw in a gas containing carbon dioxide (for example, the outside atmosphere). The drawn-in gas passes through the adsorbent material 11 within module 2. At this time, the temperature inside the cooled module 2 is, for example, the same as the ambient temperature, and the carbon dioxide in the drawn-in gas is adsorbed onto the adsorbent material 11. Gases other than carbon dioxide, such as nitrogen and oxygen, are exhausted to the outside of the carbon dioxide recovery device 1.

[0049] In the adsorption process (cooling process), the cold water from the cold water tank 22 is supplied to the module 2 as cooling water from the cold water supply line 31 via the three-way valve 50a. The cold water that has cooled the module 2 returns to the cold water tank 22 via the outlet flow path 14, the three-way valve 50b, and the cold water double line 32.

[0050] The desorption process is a process of desorbing carbon dioxide from the adsorbent 11 in module 2. In the desorption process, the control unit 4 operates a vacuum pump (not shown) to draw air into the inside of module 2, reducing the pressure to a vacuum state or close to a vacuum state. The control unit 4 also appropriately controls the operation of the three-way valves 50a and 50b of the heat exchanger 3 so that the heat transfer medium of the heat exchanger 3 flows through module 2 and supplies thermal energy, raising the temperature of the adsorbent 11 in module 2. Through the temperature rise control of the adsorbent 11 by the control unit 4, the adsorbent 11 is heated to a predetermined temperature (for example, 80°C) sufficient for the desorption process, and the carbon dioxide adsorbed on the adsorbent 11 is desorbed. In addition, in the desorption process, the control unit 4 opens a valve provided in the piping for carbon dioxide recovery, and a recovery pump for carbon dioxide recovery is operated so that the carbon dioxide desorbed in module 2 is stored in a carbon dioxide tank (not shown).

[0051] The adsorption process and the desorption process can be repeated alternately. In this case, before performing the adsorption process, a pre-cooling process is carried out to reduce the temperature of module 2, which has become hot during the desorption process, to a level where the adsorption process can be performed.

[0052] Next, we will describe the detailed control of the low-temperature water pre-cooling switching mechanism 7 performed by the control unit 4 during the pre-cooling process. Figure 2 is a flowchart showing the temperature control of the low-temperature water pre-cooling switching mechanism 7 performed by the control unit 4 during the cooling process.

[0053] The control unit 4 selectively performs two pre-cooling steps in the pre-cooling process of module 2: a first pre-cooling step (step S21) in which the bypass valve 74 of the low-temperature water pre-cooling switching mechanism 7 is closed and low-temperature water is supplied directly from the low-temperature water tank 22 to module 2A; and a second pre-cooling step (step S22) in which the bypass valve 74 is opened and the low-temperature water supplied from the low-temperature water tank 22 to module 2A is cooled in another module 2B during the adsorption process before being supplied to module 2A via the bypass path 71. The control unit 4 selects whether to perform the first pre-cooling step or the second pre-cooling step depending on the temperature conditions, etc. The pre-cooling control of module 2A will be described in detail below with reference to the flowchart in Figure 2.

[0054] Here, as shown in Figure 2, the pre-cooling preparation step S00 is performed in advance. In the pre-cooling preparation step S00, first, the pre-cooling time required to pre-cool from the temperature in the desorption process to the temperature in the adsorption process is measured in multiple modules 2. Furthermore, the pre-cooling preparation step S00 calculates the average pre-cooling time tM, which is the average of all modules 2 that perform the same process as the same set. Here, in the pre-cooling process, variations in the flow velocity of the heat transfer medium and differences in flow resistance may occur in multiple modules 2. This is thought to be due to individual differences in each module 2, mostly caused by processing accuracy during manufacturing. In pre-cooling, the cooling rate and pre-cooling time change depending on the flow rate and flow velocity of the low-temperature water. For this reason, the variation in pre-cooling time that occurs in multiple modules 2 is grasped. Furthermore, in the pre-cooling preparation step S00, modules 2 with a longer pre-cooling time than the average pre-cooling time tM are identified by comparing them with the average pre-cooling time tM. Furthermore, the pre-cooling process is selectively performed on module 2, which has a long pre-cooling time, thereby shortening the overall pre-cooling time of the apparatus. Here, we will explain using the example of selecting module 2A as the target for shortening the pre-cooling time.

[0055] The temperature cycle of module 2A will be described starting from the point when the desorption process S01 is completed. In the desorption process S01 of module 2A, the adsorbent 11 of module 2A is heated to a predetermined temperature (for example, 80°C) sufficient for the desorption process. In the desorption process S01, module 2A is heated as described above. In the desorption process S01 of module 2A, the three-way valve 50Aa connects the high-temperature water supply line 41 to the inlet side flow path 13A, the three-way valve 50Ab connects the high-temperature water return line 42 to the outlet side flow path 14A, and the bypass valve 74 is closed.

[0056] In this case, module 2B may undergo an adsorption process. In the adsorption process in module 2B, cold water is supplied directly from the cold water tank 22 to module 2B, and the cold water is recovered from module 2B to the cold water tank 22. In module 2B, the three-way valve 50Ba is closed, the three-way valve 50Bb is closed, and the bypass valve 74 is closed.

[0057] Once the detachment process S01 is complete, before starting the pre-cooling process of module 2A, the control unit 4 checks the actual temperature T of module 2 as measured by the temperature sensor 12. ＭＭ (Hereafter, module measurement temperature T) ＭＭ (This is called the temperature around module 2B measured by temperature sensor 12.) ｏｕｔ (Hereinafter, exhaust heat environmental temperature T ｏｕｔ This is called [name].] and [name] are compared. Exhaust heat ambient temperature T ｏｕｔ This fluctuates depending on factors such as the season. The exhaust heat environment temperature T of Module 2B. ｏｕｔ This relates to the first temperature condition T1 that allows module 2A, which is downstream of the bypass path 71, to be pre-cooled. Module measurement temperature T of module 2B ＭＭ The exhaust heat environment temperature T ｏｕｔ In other words, the temperature T of the gas drawn into module 2B ｏｕｔ It can descend to a certain point without energy loss. Also, the module measurement temperature T of module 2A ＭＭ The exhaust heat environment temperature T ｏｕｔ In other words, this is the temperature in module 2A after pre-cooling, i.e., the target temperature for pre-cooling completion.

[0058] Note that before the pre-cooling process of module 2A begins, module 2A is either in the detachment process or stopped. Therefore, in module 2A, the module measurement temperature T ＭＭ and exhaust heat environment temperature T ｏｕｔ This may differ. In this case, the module measurement temperature T ＭＭ The exhaust heat environment temperature T ｏｕｔ It is often higher than this. After this, the process proceeds to the next step S11 in order to start the pre-cooling process of module 2A. Note that module 2B is in the adsorption process, so the module measurement temperature T ＭＭ and exhaust heat environment temperature T ｏｕｔ It is equivalent to this.

[0059] When starting the pre-cooling of module 2A, in step S11, the control unit 4 first sets the module measurement temperature T of module 2B. ＭＭ And the temperature T of the cold water in the cold water tank 22, as measured by the temperature sensor 27.ＬＴ Compare the following: Temperature T of cold water. ＬＴ From module measurement temperature T ＭＭ If the control unit 4 determines that the difference obtained by subtracting is smaller than the first temperature condition T1, it proceeds to step S21 and performs the first pre-cooling process. Here, the first temperature condition T1 is stored in the storage unit 5 and read by the control unit 4. In step S11, the control unit 4 makes the above temperature difference determination with respect to the first temperature condition T1 stored in the storage unit 5. The first temperature condition T1 may be any value, but for example it may be 5°C.

[0060] In step S11, the control unit 4 determines the module measurement temperature T ＭＭ and the temperature T of cold water ＬＴ This is a comparison to determine whether outside air cooling is possible in module 2B. Here, the temperature T of the low-temperature water is... ＬＴ From module measurement temperature T ＭＭ If the difference after subtracting is small, meaning that outside air cooling is not possible in module 2B, the process proceeds to step S21, and pre-cooling of module 2A is performed separately from module 2B. In other words, the temperature of the cold water in the cold water tank 22 T ＬＴ is the exhaust heat environment temperature (precooling completion target temperature) T ｏｕｔ Because it is close to the module, pre-cooling of module 2A is performed using cold water supplied directly from the cold water tank 22. The cold water used to pre-cool module 2A is recovered into the cold water tank 22. Similarly, the adsorption process is continued in module 2B. In the adsorption process in module 2B, cold water is supplied directly from the cold water tank 22 to module 2B and recovered from module 2B into the cold water tank 22. At this point, the following cases are possible when proceeding to step S21.

[0061] • Temperature T of cold water ＬＴ is the exhaust heat environment temperature (precooling completion target temperature) T ｏｕｔ It is close to that. In other words, the temperature T of cold water ＬＴ The temperature is high, and there is excess waste heat from the low-temperature water side. At the same time, the waste heat environment temperature T ｏｕｔThe ambient temperature shown is high, making it impossible to cool module 2B. Therefore, pre-cooling of module 2A, which has the bypass path 71 connected to module 2B, is not performed. • Temperature T of the low-temperature water ＬＴ is the exhaust heat environment temperature (precooling completion target temperature) T ｏｕｔ It is close to that. In other words, the temperature T of cold water ＬＴ The temperature is low, and at the same time, the exhaust heat environment temperature T ｏｕｔ The ambient temperature shown is low. In this case, the temperature T of the cold water is low. ＬＴ If the temperature is too low, it becomes necessary to recover the waste heat as a heat source for the heat exchanger 21, which worsens energy efficiency. Therefore, the sensible heat possessed by the auxiliary equipment 61 and others is used to raise the temperature of the low-temperature water T. ＬＴ It is necessary to increase the temperature. In other words, the sensible heat contained in module 2A is recovered in order to use it as a heat source for heat source 21. For this reason, pre-cooling of module 2A, which is connected to module 2B via the bypass path 71, is not performed.

[0062] • Temperature T of cold water ＬＴ is the exhaust heat environment temperature (precooling completion target temperature) T ｏｕｔ Module measurement temperature T is equal to ＭＭ It is close to that. In other words, the exhaust heat environment temperature T ｏｕｔ The ambient temperature shown is high, and cooling of module 2B is possible, but it is necessary to recover the sensible heat possessed by module 2A in order to use it as a heat source for heat source 21. For this reason, pre-cooling of module 2A, which is connected to module 2B via the bypass path 71, is not performed. • Temperature T of the low-temperature water ＬＴ The exhaust heat environment temperature T ｏｕｔ Module measurement temperature T is equal to ＭＭ It is close to that. In other words, the exhaust heat environment temperature T ｏｕｔ The ambient temperature shown is high, making it impossible to cool module 2B.

[0063] In the above case, the process proceeds to step S21 to perform the first pre-cooling process. In the first pre-cooling process performed in step S21, the bypass valve 74 is closed in the water pre-cooling switching mechanism 7, and the waste heat from module 2A is recovered into the low-temperature water tank 22 via the low-temperature water double line 32. In the low-temperature water tank 22, the low-temperature water in the low-temperature water tank 22 is cooled via the heat source 21, and the temperature of the high-temperature water in the high-temperature water tank 23 is raised. In step S21, the heat exchanger 3 drives the circulating water pump to flow low-temperature water from the low-temperature water tank 22 towards module 2A, and the pre-cooling process of module 2A is performed. In this case, the module measurement temperature T ＭＭ and the temperature T of cold water ＬＴ Although the difference is small, it falls within a predetermined range, thus suppressing or preventing the pre-cooling time tA of module 2A from becoming longer due to the temperature of the low-temperature water.

[0064] On the other hand, in step S11, the control unit 4 determines the temperature T of the cold water. ＬＴ From the exhaust heat environment temperature T ｏｕｔ Module measurement temperature T is equal to ＭＭ If the difference after subtracting is determined to be greater than the first temperature condition T1, the process proceeds to step S12. In step S12, the control unit 4 determines whether or not to further lower the temperature by flowing the low-temperature water used for pre-cooling module 2A into module 2B beforehand. The criterion for this determination is whether or not the pre-cooling time tA of module 2A is longer than the average pre-cooling time tM. If, in step S12, the control unit 4 determines that the pre-cooling time tA of module 2A is not longer than the average pre-cooling time tM, the control unit 4 proceeds to step S21 to perform the first pre-cooling process. In other words, it determines that there is no need to shorten the pre-cooling time of module 2A. On the other hand, if, in step S12, the control unit 4 determines that the pre-cooling time tA of module 2A is longer than the average pre-cooling time tM, the control unit 4 proceeds to step S13 to determine that the second pre-cooling process can be performed.

[0065] In step S13, the control unit 4 determines the temperature T of the cold water in the cold water tank 22 measured by the temperature sensor 27. ＬＴHowever, it is determined whether or not it is greater (higher) than the second temperature condition T2. ​​The second temperature condition T2 is a reference value for whether or not there is excess exhaust heat. In other words, the second temperature condition T2 is a reference value for whether or not cooling is possible by connecting the bypass path 71 to module 2A. In step S13, the control unit 4 makes the above determination for the second temperature condition T2 stored in the storage unit 5. The second temperature condition T2 may be any value, but for example it may be 25°C. Then, the control unit 4 determines whether the temperature T of the low-temperature water ＬＴ If it is determined that the temperature is lower than the second temperature condition T2, the process proceeds to step S21 to perform the first cooling process. In this case, the following situations are possible when proceeding to step S21.

[0066] • Temperature T of cold water ＬＴ The exhaust heat environment temperature T ｏｕｔ Module measurement temperature T is equal to ＭＭ It is relatively high compared to the temperature T of cold water. ＬＴ The waste heat from the low-temperature water line is high enough that there is excess heat. At the same time, the module measurement temperature T ＭＭ The exhaust heat environment temperature T is equal to ｏｕｔ The ambient temperature shown is high, but it is within the range where module 2B can be cooled. However, the temperature T of the cold water... ＬＴ Since the temperature is still too low, the energy efficiency of the heat exchanger 3 deteriorates, so the sensible heat of module 2A is used to raise the temperature of the cold water T ＬＴ The temperature needs to be increased. In other words, the sensible heat contained in module 2A is recovered to be used as a heat source for heat source 21. For this reason, pre-cooling of module 2A, which is connected to module 2B via the bypass path 71, is not performed. • Temperature T of the low-temperature water ＬＴ Module measurement temperature T ＭＭ The exhaust heat environment temperature T is equal to ｏｕｔ It is relatively high compared to the temperature T of cold water. ＬＴ The waste heat from the low-temperature water line is high enough that there is excess heat. At the same time, the waste heat ambient temperature T ｏｕｔ The ambient temperature shown is high, making it impossible to cool module 2B. Therefore, pre-cooling of module 2A, which has the bypass path 71 connected to module 2B, is not performed.

[0067] In the above case, proceed to step S21 and perform the first cooling process.

[0068] On the other hand, in step S13, the control unit 4 determines the temperature T of the cold water. ＬＴ If it is determined that the temperature is higher than the second temperature condition T2, the process proceeds to step S22 to perform the second cooling process. If the control unit 4 determines that outside air cooling is possible, the process proceeds to step S22, and the bypass valve 74 is opened so that the bypass path 71 connects the outlet side flow path 14B and the inlet side flow path 13A. Then, the low-temperature water flowing from the low-temperature water supply line 31 to module 2A is cooled further in module 2B, which is already adsorbing water, before flowing to module 2A. The low-temperature water supplied from the low-temperature water tank 22 flows in the order of module 2B and then module 2A. The low-temperature water does not flow directly from module 2B to the low-temperature water return line 32. At this time, the heat discharged from module 2A is discharged to the outside via module 2B after passing through the low-temperature water tank 22. In this cooling process with the bypass path 71 connected to module 2B, i.e., the second cooling process, no heat recovery is performed because the sensible heat of module 2A is released into the outside air. The following cases are possible when proceeding to step S22.

[0069] • Temperature T of cold water ＬＴ Module measurement temperature T ＭＭ The exhaust heat environment temperature T is equal to ｏｕｔ It is sufficiently high compared to that. In other words, the temperature T of cold water ＬＴ This is because there is excess waste heat from the low-temperature water line. At the same time, the waste heat ambient temperature T ｏｕｔ The ambient temperature shown is high, but it is within the range where module 2B can be cooled.

[0070] In the above case, the process proceeds to step S22, where a second cooling step is performed. In the second cooling step performed in step S22, in the low-temperature water precooling switching mechanism 7, the bypass valve 74 is opened, so that the exhaust heat of the module 2A is discharged to the outside by the module 2B via the low-temperature water return line 32 and by the low-temperature water passing through the low-temperature water tank 22. At the same time, the exhaust heat of the module 2A raises the temperature of the high-temperature water in the high-temperature water tank 23 via the low-temperature water tank 22 by the heat source device 21. Driven by the circulation water pump, the low-temperature water circulates in sequence along one line formed by the module 2A, the outlet-side flow path 14A, the three-way valve 50Ab, the low-temperature water return line 32, the low-temperature water tank 22, the low-temperature water supply line 31, the three-way valve 50Ba, the inlet-side flow path 13B, the module 2B, the outlet-side flow path 14B, the bypass valve 74, the bypass path 71, the inlet-side flow path 13A, and the module 2A. In the second cooling step, since the temperature of the low-temperature water in the low-temperature water tank 22 is high, it is possible to suppress or prevent the temperature reduction of low-temperature water in the module 2B from being hindered due to the temperature of the low-temperature water. When the precooling step of precooling the module 2A is completed, the process proceeds to step S02, where an adsorption step of cooling the module 2A is performed.

[0071] Note that, the temperature T of the low-temperature water in the low-temperature tank 22 in the first precooling step ＬＴ is, for example, 35°C. The target precooling completion temperature of the module 2A in the first precooling step is, for example, 40°C. The temperature T of the low-temperature water in the low-temperature tank 22 in the second precooling step ＬＴ is, for example, 35°C. The target precooling completion temperature of the module 2A in the second precooling step is, for example, 30°C. The exhaust heat environment temperature T in the second precooling step ｏｕｔis, for example, 20°C. The temperature of the high-temperature water in the high-temperature water tank 23 in the desorption step is, for example, 80°C. The target temperature of the module 2 in the desorption step is, for example, 80°C. The pre-cooling completion target temperature of the module 2A in the second pre-cooling step is lower than the pre-cooling completion target temperature of the module 2A in the first pre-cooling step. However, compared with the pre-cooling time until the end of the first pre-cooling step, the pre-cooling time until the end of the second pre-cooling step is shorter. This is because in the second pre-cooling step, the waste heat of the module 2A is released from the module 2B to the outside by using the outside air temperature lower than the temperature of the low-temperature water in the low-temperature tank 22.

[0072] Furthermore, the driving state of the circulation water pump can be made lower in the first pre-cooling step than in the second pre-cooling step. That is, in the second pre-cooling step, the driving level of the circulation water pump can be made higher than that in the first pre-cooling step.

[0073] As described above, in the carbon dioxide recovery device 1 according to the present embodiment, when the pre-cooling time tA is longer than the average pre-cooling time tM before the module 2A executes the adsorption step, the control unit 4 selectively implements: a first pre-cooling step of directly supplying low-temperature water from the low-temperature water tank 22 to the module 2A; and a second pre-cooling step of supplying low-temperature water to the module 2A after lowering the temperature of the low-temperature water in the module 2B on the upstream side of the module 2A.

[0074] Then, the control unit 4 controls the temperature T of the low-temperature water in the low-temperature water tank 22 ＬＴ minus the measured module temperature T of the module 2B ＭＭ When the difference obtained by subtraction is smaller than the first temperature condition T1, the first pre-cooling step is performed, and the temperature T of the low-temperature water in the low-temperature water tank 22 ＬＴ minus the measured module temperature T of the module 2B ＭＭ When the difference obtained by subtraction is larger than the first temperature condition T1 and the temperature T of the low-temperature water ＬＴ is smaller than the second temperature condition T2, the first pre-cooling step for the module 2A is performed. Also, the temperature T of the low-temperature water in the low-temperature water tank 22 ＬＴ minus the measured module temperature T of the module 2B ＭＭ When the difference obtained by subtraction is larger than the first temperature condition T1 and the temperature T of the low-temperature waterＬＴ If the second temperature condition T2 is greater than the second temperature condition T2, the second pre-cooling process of module 2A is performed.

[0075] Therefore, the exhaust heat environment temperature T fluctuates due to seasonal factors. ｏｕｔ Without being affected, the temperature of the cold water in the cold water tank 22 before performing the cooling process of module 2A T ＬＴ In contrast, pre-cooling of module 2A can be performed in a predetermined process. This makes it possible to shorten the cycle pitch in multiple modules 2.

[0076] Heating module 2 with cold water from cold water tank 22 is useful from an energy-saving perspective when the outside temperature is low (for example, 5°C) such as in winter. When the outside temperature is low, the temperature T of the cold water in cold water tank 22 depends on the operating conditions of the heat source 21. ＬＴ Although it fluctuates with respect to the ambient temperature, it is not affected by this fluctuation range, and the exhaust heat environment temperature (ambient temperature) T ｏｕｔ Measurement temperature T of module 2B in the adsorption process is approximately equivalent to ＭＭ Without being affected by fluctuations, the module 2A can be sufficiently cooled by the low-temperature water in the low-temperature water tank 22.

[0077] Furthermore, in the carbon dioxide recovery apparatus 1 according to this embodiment, when multiple modules 2 perform the adsorption process and the desorption process, the waste heat environment temperature T fluctuates due to seasonal factors. ｏｕｔ Without being affected by the above, the pre-cooling process for module 2A is executed, where the pre-cooling time tA is longer than the average pre-cooling time tM. The control unit 4 supplies low-temperature water from the low-temperature water tank 22 to module 2A either directly or via module 2B. This allows multiple modules 2 to be cooled to a temperature at which the adsorption process can be started, with a pre-cooling time approximately the same as the average pre-cooling time tM.

[0078] Even if there is variation in the pre-cooling time across multiple modules 2, the temperature T of the cold water in the cold water tank 22 remains constant. ＬＴ From the exhaust heat environment temperature T ｏｕｔ If the difference obtained by subtracting is greater than the first temperature condition T1, and the temperature of the cold water in the cold water tank 22 is TＬＴ Performing the second pre-cooling process only when the temperature is greater than the second temperature condition T2 is particularly useful when the outside temperature is low (e.g., 5°C), such as in winter. This point will be explained below. When the outside temperature is high, such as in summer, the amount of heat dissipated into the outside air from the various auxiliary equipment is small, so most of the heat discharged from module 2 (waste heat) is recovered by the low-temperature water supplied from the low-temperature water tank 22. For this reason, the temperature of the low-temperature water in the low-temperature water tank 22 T ＬＴ The temperature becomes relatively high. Therefore, the temperature T of the cold water in the cold water tank 22 ＬＴ The exhaust heat from module 2 reduces the exhaust heat ambient temperature T. ｏｕｔ It is often higher than the above.

[0079] On the other hand, when the outside temperature is low, such as in winter, a large amount of heat is dissipated from module 2 into the outside air. Therefore, the amount of heat recovered by the cold water supplied from the cold water tank 22 from the heat discharged from module 2 (waste heat) is small. For this reason, the temperature T of the cold water in the cold water tank 22 is small. ＬＴ The temperature becomes relatively low. As a result, the temperature T of the cold water in the cold water tank 22 ＬＴ However, the exhaust heat environment temperature T ｏｕｔ It is highly likely that the temperature will be close to this. Therefore, the temperature of the cold water in the cold water tank 22 is T ＬＴ The exhaust heat environment temperature T ｏｕｔ It is useful to perform the second pre-cooling process only if the above conditions are met, and the first pre-cooling process otherwise.

[0080] Although embodiments of the present invention have been described above, the invention is not limited to the embodiments and modifications described above. Furthermore, the effects described in the above embodiments are merely a list of preferred effects and are not limited to those described in the above embodiments.

[0081] The present invention is not limited to being applied to carbon dioxide recovery devices, but may also be applied to gas recovery devices that recover a specific gas (specific gas) contained in any gas (mixed gas). In this case, the adsorbent placed in the module to adsorb the specific gas only needs to have the property of adsorbing the specific gas at low temperatures and desorbing (releasing) the specific gas at high temperatures and when the concentration of the specific gas in the surrounding environment is low.

[0082] 1...Carbon dioxide capture device 2...Module 2A...Module (first module) 2B...Module (second module) 3...Heat exchange device 4...Control unit 5...Memory unit 11...Adsorbent 13, 13A, 13B...Inlet flow path 14, 14A, 14B...Outlet flow path 21...Heat source 22...Low temperature water tank (low temperature heat transfer medium tank) 23...High temperature water tank (high temperature heat transfer medium tank) 7...Low temperature water pre-cooling switching mechanism (low temperature heat transfer medium pre-cooling switching mechanism) 71...Bypass path 74...Bypass valve (bypass valve) t, tA, tM...Pre-cooling time T1...First temperature condition T2...Second temperature condition T ＬＴ ...Temperature T of the cold water in the cold water tank 22 ｏｕｔ ...Exhaust heat environmental temperature T ＭＭ ...Measurement temperature of module 2

Claims

1. A plurality of modules having an adsorbent inside, which perform an adsorption step of drawing a gas containing carbon dioxide onto the adsorbent to adsorb the carbon dioxide, and a desorption step of heating the area around the adsorbent to desorb the carbon dioxide from the adsorbent; a heat exchanger having a heat pump type heat source that heats a high-temperature heat transfer medium and cools a low-temperature heat transfer medium, a high-temperature heat transfer medium tank that stores the high-temperature heat transfer medium heated by the heat source, and a low-temperature heat transfer medium tank that stores the low-temperature heat transfer medium cooled by the heat source, which performs a heating step of supplying the high-temperature heat transfer medium to heat the modules and a cooling step of supplying the low-temperature heat transfer medium to cool the modules; a bypass path connecting an inlet-side flow path that supplies the low-temperature heat transfer medium to a first module among the plurality of modules and an outlet-side flow path from which the low-temperature heat transfer medium flows out of a second module; a bypass valve provided in the bypass path; and a control unit, wherein the control unit performs the cooling step of the first module before the adsorption step of the second module is performed. A carbon dioxide recovery device comprising: a first pre-cooling step in which, when the difference between the temperature of the low-temperature heat medium in the low-temperature heat medium tank and the temperature of the gas drawn into the second module is smaller than the first temperature condition, the bypass valve is closed and the low-temperature heat medium is supplied from the low-temperature heat medium tank to the first module; and a second pre-cooling step in which, when the difference between the temperature of the low-temperature heat medium in the low-temperature heat medium tank and the temperature of the gas drawn into the second module is larger than the first temperature condition, the bypass valve is opened and the low-temperature heat medium is supplied from the second module to the first module via the bypass path, or the first pre-cooling step is performed.

2. The control unit performs a pre-cooling preparation step in advance for each of the plurality of modules, which involves measuring the pre-cooling time required to pre-cool from the temperature of the desorption step to the temperature of the adsorption step and calculating the average pre-cooling time, which is the average of these values; the control unit performs the second pre-cooling step with the module having the longer pre-cooling time as the first module if there is a module among the plurality of modules whose pre-cooling time is longer than the average pre-cooling time, and if there is no module whose pre-cooling time is longer than the average pre-cooling time, the control unit performs the first pre-cooling step, according to claim 1.

3. The carbon dioxide recovery apparatus according to claim 2, wherein the control unit performs the second pre-cooling step when the temperature of the low-temperature heat medium in the low-temperature heat medium tank is higher than the second temperature condition, and performs the first pre-cooling step when the temperature of the low-temperature heat medium in the low-temperature heat medium tank is lower than the second temperature condition, before performing the cooling step of the first module during the adsorption step of the second module.

4. The carbon dioxide recovery apparatus according to claim 3, wherein the control unit performs the cooling step of the first module after performing the first pre-cooling step or the second pre-cooling step.

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