Carbon dioxide capture system

Abstract

To provide a carbon dioxide recovery system which can perform optimal recovery treatment control according to a peripheral situation.SOLUTION: A carbon dioxide recovery system recovers carbon dioxide from mixed gas containing carbon dioxide by electrochemical reaction. The carbon dioxide recovery system includes: a carbon dioxide recovery tank for storing the recovered carbon dioxide; a recovery device which has an electrochemical cell and a housing for storing the electrochemical cell, and where the mixed gas is supplied to the inside the housing; and a control device for performing recovery treatment control including power application control whether a first potential or a second potential is applied to the electrochemical cell. The control device acquires peripheral information indicating the peripheral situation of the carbon dioxide recovery system (S11). The control device sets control contents of recovery treatment control, according to the peripheral information (S12 to S14).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a carbon dioxide recovery system for recovering carbon dioxide from a mixed gas containing carbon dioxide.

Background Art

[0002] In Patent Document 1, a gas separation system for separating carbon dioxide from a mixed gas containing carbon dioxide by an electrochemical reaction has been proposed. In this gas separation system, a mixed gas containing carbon dioxide is introduced into a housing in which an electrochemical cell is disposed. In a charging mode in which electrons are directed to the negative electrode of the electrochemical cell, the electroactive material provided at the negative electrode is reduced. Therefore, a bond between the electroactive material at the negative electrode and carbon dioxide occurs, and carbon dioxide is separated from the mixed gas. On the other hand, in a discharging mode in which an electron flow is generated in a direction opposite to the electron flow during the charging mode, the electroactive material at the negative electrode is oxidized. As a result, carbon dioxide is released from the electroactive material at the negative electrode.

Prior Art Documents

Patent Documents

[0003] [[ID=2 1]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is considered that the carbon dioxide recovery system is affected by the surrounding situation. However, there is a problem that the carbon dioxide recovery system does not have control content considering the surrounding situation.

[0005] The present disclosure has been made in view of the above points, and an object thereof is to provide a carbon dioxide recovery system capable of performing optimal recovery process control according to the surrounding situation.

Means for Solving the Problems

[0006] A carbon dioxide capture system that recovers carbon dioxide from a mixed gas containing carbon dioxide by an electrochemical reaction, A carbon dioxide capture tank (16) for storing the captured carbon dioxide, An electrochemical cell having a working electrode containing an adsorbent material capable of adsorbing carbon dioxide and a counter electrode paired with the working electrode, and a housing that houses the electrochemical cell, with at least one recovery unit (12) into which a mixed gas is supplied, The system includes a control device (17) that performs recovery process control, which includes power application control to apply a first potential between the working electrode and the counter electrode so that the electrochemical cell adsorbs carbon dioxide, or to apply a second potential between the working electrode and the counter electrode so that the electrochemical cell desorbs the adsorbed carbon dioxide. The control device is It is configured to communicate with an external system (20), Surrounding information showing the conditions around the carbon dioxide capture system This includes weather information from external systems, including current and future weather conditions. Information acquisition step to obtain (S1 1) and, Weather information The system includes a control setting step (S12-S14, 30) for setting the control content of the recovery process control accordingly. 、 The control setting step is, Current weather conditions and future weather conditions We will determine whether or not it will affect carbon dioxide capture, and if it is determined that it will have an impact, Switching from the current mode to a proactive mode that anticipates future weather conditions and executes recovery processing control in advance. Switching to carbon capture systems.

[0007] This cormorant The carbon dioxide capture system sets the control content for the capture process in accordance with surrounding information. Therefore, the carbon dioxide capture system can perform optimal capture process control according to the surrounding conditions.

[0008] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in embodiments described later, in order to facilitate understanding of this disclosure, and are not intended to limit the scope of this disclosure in any way.

[0009] Regarding the technical features described in each claim of the claims other than the features of the present disclosure described above, they will become clear from the description of the embodiments and the accompanying drawings described later.

Brief Description of the Drawings

[0010] [Figure 1] It is a diagram showing the configuration of a carbon dioxide recovery system according to an embodiment. [Figure 2] It is a flowchart showing the processing in a control device for executing a series of control sequences for carbon dioxide recovery. [Figure 3] It is a flowchart showing the pre-execution determination process in the control device. [Figure 4] It is a time chart showing the operations of each part when the process shown in the flowchart of FIG. 2 is executed. [Figure 5] It is an explanatory diagram for explaining the adsorption mode, scavenging mode, and desorption / recovery mode included in a series of control sequences. [Figure 6] It is a diagram showing an example of adsorption amount change map data. [Figure 7] It is a diagram showing an example of recovery amount change map data. [Figure 8] It is an enlarged view of part VIII of FIG. 7. [Figure 9] It is a flowchart showing the map creation process for creating adsorption amount change map data. [Figure 10] It is an explanatory diagram for explaining an example of a method for estimating the maximum adsorption amount and the maximum adsorption amount time of an electrochemical cell. [Figure 11] It is a flowchart showing the setting process of the target carbon dioxide adsorption amount. [Figure 12] It is a drawing showing the relationship between weather conditions and carbon dioxide recovery. [Figure 13] It is a drawing showing the pre-taking target conditions. [Figure 14] It is an image plane showing the pre-taking mode. [Figure 15]It is a drawing showing the relationship between the carbon dioxide adsorption amount and the adsorption time, and the relationship between the carbon dioxide adsorption amount and the recovery time. [Figure 16] It is a flowchart showing the stop determination process in the modified example. [Figure 17] It is a drawing showing the stop mode in the modified example.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the carbon dioxide recovery system according to the embodiment of the present disclosure will be described in detail with reference to the drawings. In the plurality of drawings, the same reference numerals are assigned to parts that are identical or equivalent to each other. The carbon dioxide recovery system according to the present embodiment recovers carbon dioxide from a mixed gas containing carbon dioxide (for example, atmospheric gas). The mixed gas from which carbon dioxide has been removed is discharged to the outside (atmosphere). FIG. 1 shows the configuration of the carbon dioxide recovery system 10 according to the present embodiment.

[0012] The carbon dioxide recovery system 10 shown in FIG. 1 includes a flow path opening / closing valve 11, a recovery device 12, a pump 13, a flow path switching valve 14, a sensor 15, a CO2 recovery tank 16, a control device 17, and a blower 19. The flow path opening / closing valve 11, the recovery device 12, the pump 13, the flow path switching valve 14, and the blower 19 can also be said to be components for carbon dioxide recovery that are controlled by the control device 17.

[0013] The opening / closing state of the flow path opening / closing valve 11 is controlled by the control device 17. When the flow path opening / closing valve 11 is opened, the mixed gas containing carbon dioxide can be introduced into the recovery device 12 through the flow path piping that connects the outside (atmosphere) and the inside of the recovery device 12. On the other hand, when the flow path opening / closing valve 11 is closed, the flow path piping that connects the outside and the inside of the recovery device 12 is blocked, and the recovery device 12 is sealed from the outside.

[0014] The blower 19 is driven by the control device 17 when the flow path valve 11 is open, and sends a mixed gas containing carbon dioxide into the recovery unit 12 via a flow path piping that connects the outside and the inside of the recovery unit 12. However, the blower 19 may be omitted. Alternatively, the pump 13 may perform the role of the blower 19. That is, when the flow path valve 11 is open, the pump 13 may be driven to draw the mixed gas containing carbon dioxide from the outside into the recovery unit 12 via the aforementioned flow path piping.

[0015] The recovery unit 12 includes an electrochemical cell, for example, located inside a metal casing. The electrochemical cell is capable of adsorbing carbon dioxide through an electrochemical reaction, separating it from the mixed gas, and desorbing the adsorbed carbon dioxide, which is then stored in the CO2 recovery tank 16 by a pump 13. The recovery unit 12 has two openings. One opening is an inlet for introducing a mixed gas containing carbon dioxide from the outside into the casing of the recovery unit 12. The other opening is an outlet for discharging the mixed gas from which carbon dioxide has been removed, or the carbon dioxide desorbed from the electrochemical cell. A flow channel piping connecting the outside and the inside of the recovery unit 12 is connected to the inlet, and a flow channel piping equipped with the pump 13 is connected to the outlet. Note that "inside the recovery unit 12" is synonymous with "inside the casing."

[0016] Multiple electrochemical cells are stacked inside the housing of the recovery unit 12. The stacking direction of the multiple electrochemical cells is perpendicular to the flow direction of the mixed gas. Each electrochemical cell is plate-shaped, and its plate surface is arranged to intersect with the cell stacking direction. A predetermined gap is provided between adjacent electrochemical cells. The gap provided between adjacent electrochemical cells serves as a gas channel through which the mixed gas flows.

[0017] Each electrochemical cell is constructed by stacking components such as a working electrode current collector layer, working electrode, separator, counter electrode, and counter electrode current collector layer in the order described. The working electrode is the negative electrode, and the counter electrode, which is paired with the working electrode, is the positive electrode. By changing the potential difference applied between the working electrode and the counter electrode, electrons can be supplied to the working electrode, causing carbon dioxide to be adsorbed onto the carbon dioxide adsorbent on the working electrode, or electrons can be released from the working electrode, causing the adsorbed carbon dioxide to be desorbed. The carbon dioxide adsorbent corresponds to the adsorbent material.

[0018] The working electrode current collector layer consists of a porous conductive material having pores through which a mixed gas containing carbon dioxide can pass. The working electrode current collector layer only needs to have gas permeability and conductivity, and materials such as metallic materials or carbonaceous materials can be used to form the working electrode current collector layer.

[0019] The working electrode is formed from a mixture of materials including a carbon dioxide adsorbent, a conductive material, and a binder. The carbon dioxide adsorbent has the property of adsorbing carbon dioxide by accepting electrons and desorbing the adsorbed carbon dioxide by releasing electrons. For example, polyanthraquinone can be used as the carbon dioxide adsorbent. The conductive material forms a conductive path to the carbon dioxide adsorbent. For example, carbon materials such as carbon nanotubes, carbon black, and graphene can be used as the conductive material. The binder is for holding the carbon dioxide adsorbent and the conductive material. For example, a conductive resin can be used as the binder. For example, the conductive resin can be an epoxy resin containing Ag as a conductive filler, or a fluororesin such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF).

[0020] The counter electrode is formed from a mixture of materials including an electroactivating auxiliary, a conductive substance, and a binder. The conductive substance and binder of the counter electrode are the same as those of the working electrode, so their explanation is omitted. The electroactivating auxiliary of the counter electrode is composed of a material having an active substance that acts as an electron donor. The electroactivating auxiliary of the counter electrode is an auxiliary electroactive species that facilitates electron transfer with the carbon dioxide adsorbent of the working electrode. As an electroactivating auxiliary, for example, a metal complex that enables electron transfer by changing the valence of metal ions can be used. Examples of such metal complexes include cyclopentadienyl metal complexes such as ferrocene, nickerosene, and cobaltocene, or porphyrin metal complexes. These metal complexes may be polymers or monomers. The counter electrode current collector layer is formed from a conductive material such as a metal material or a carbonaceous material, similar to the working electrode current collector layer.

[0021] A separator is placed between the working electrode and the counter electrode to separate them. The separator is an insulating ion-permeable membrane that prevents physical contact between the working electrode and the counter electrode, thereby suppressing electrical short circuits, while also allowing ions to pass through. Cellulose membranes, polymers, composite materials of polymers and ceramics, etc., can be used as separators.

[0022] Furthermore, the electrochemical cell is equipped with an electrolyte that spans both the working electrode and the counter electrode. For example, an ionic liquid can be used as the electrolyte. An ionic liquid is a salt of a liquid that is non-volatile at room temperature and pressure.

[0023] Pump 13 sucks residual mixed gas remaining in the recovery unit 12 and releases it to the outside (i.e., scavenges the residual mixed gas in the recovery unit 12), and when the carbon dioxide adsorbent desorbs the carbon dioxide it has adsorbed, pump 13 sucks the desorbed carbon dioxide from the recovery unit 12 and discharges it toward the CO2 recovery tank 16. When pump 13 scavenges the residual mixed gas in the recovery unit 12, the flow path shut-off valve 11 shuts off the flow path piping that connects the outside and the inside of the recovery unit 12. Therefore, the scavenging of residual mixed gas in the recovery unit 12 is performed by vacuuming with pump 13. Furthermore, the subsequent discharge of carbon dioxide to the CO2 recovery tank 16 is also performed in a state closer to a vacuum than atmospheric pressure.

[0024] The flow path switching valve 14 is a three-way valve that switches the flow path of the gas flowing through the piping downstream of the pump 13. The switching of the flow path of the flow path switching valve 14 is controlled by the control device 17. Specifically, when a mixed gas containing carbon dioxide is introduced into the recovery unit 12, and when residual mixed gas in the recovery unit 12 is scavenged by the pump 13, the control device 17 controls the flow path switching valve 14 to connect the piping downstream of the pump 13 to the outside (atmosphere). As a result, the mixed gas from which carbon dioxide has been removed, and the residual mixed gas in the recovery unit 12, are released to the outside. On the other hand, when the carbon dioxide adsorbent desorbs the carbon dioxide, and the pump 13 sucks the desorbed carbon dioxide from the recovery unit 12 and discharges it, the control device 17 controls the flow path on / off valve 11 to connect the piping downstream of the pump 13 to the CO2 recovery tank 16. As a result, the carbon dioxide recovered by the recovery unit 12 can be stored in the CO2 recovery tank 16.

[0025] Sensor 15 detects the carbon dioxide concentration and flow rate of the gas flowing through the piping connected to the CO2 recovery tank 16 at predetermined time intervals. The control device 17 can calculate (detect) the amount of carbon dioxide recovered in the CO2 recovery tank 16 from the carbon dioxide concentration and flow rate detected by sensor 15. This amount of carbon dioxide recovered is the result detected via the sensor. Alternatively, the amount of carbon dioxide recovered may be calculated by sensor 15. In this case, sensor 15 outputs the amount of carbon dioxide recovered to the control device 17. The amount of carbon dioxide recovered can also be called the carbon dioxide monitor value. The amount of carbon dioxide recovered can also simply be called the recovered amount.

[0026] The carbon dioxide capture system 10 may also be equipped with various other sensors in addition to sensor 15. These include sensors that detect a current corresponding to the voltage applied between the working electrode and counter electrode of the electrochemical cell, sensors that detect the suction pressure or suction speed of the pump 13, sensors that detect the temperature of the atmosphere (mixed gas), sensors that detect the humidity of the atmosphere, and sensors that detect the carbon dioxide concentration of the atmosphere. The control device 17 acquires the sensor signals detected by these sensors.

[0027] The control device 17 consists of a well-known microcomputer and its peripheral devices, including a storage device 171 such as a CPU, ROM, and RAM. The control device 17 is equipped with a communication device 172 as an example of a peripheral device. The storage device 171 stores adsorption amount change map data and recovery amount change map data. The adsorption amount change map data can also be called adsorption amount change data. The recovery amount change map data is associated with adsorption time and target carbon dioxide adsorption amount, as shown in Figure 6. The recovery amount change map data is associated with changes in carbon dioxide recovery amount and target carbon dioxide adsorption amount, as shown in Figures 7 and 8. The target carbon dioxide adsorption amount is also referred to as the maximum adsorption amount. The adsorption time is also referred to as the adsorption mode execution time. The adsorption amount change map data and recovery amount change map data will be explained in detail later.

[0028] The control device 17 performs various calculations based on a control program stored in a storage medium such as ROM, and controls the operation of various controlled devices such as the flow path on / off valve 11, the recovery unit 12, the pump 13, the flow path switching valve 14, and the blower 19. It can also be said that the control device 17 controls the drive of the pump 13. Furthermore, the targets of drive control may include not only the pump 13, but also the flow path on / off valve 11, the flow path switching valve 14, and the blower 19. In this embodiment, the control device 17 controls the operation of various controlled devices so that a series of control sequences for carbon dioxide recovery, including at least an adsorption mode and a desorption / recovery mode, are executed in the carbon dioxide recovery system 10. In other words, the control device 17 performs recovery process control so that the control sequence is executed. Note that the control sequence may also include a scavenging mode in addition to the above. The desorption / recovery mode indicates that the desorption mode and the recovery mode are combined into a single mode.

[0029] Furthermore, the control device 17 is configured to communicate with the external system 20, which will be described later, via the communication device 172. The control device 17 receives peripheral information from at least the external system 20 using the communication device 172. However, the control device 17 may also acquire peripheral information from the external system 20 without using the communication device 172. In other words, the control device 17 may receive peripheral information through an input device. In this case, the control device 17 does not need to be equipped with the communication device 172.

[0030] The surrounding information refers to information indicating the conditions surrounding the carbon dioxide capture system 10. It can also be said that the surrounding information refers to the conditions surrounding the carbon dioxide capture component. In this embodiment, weather information is used as an example of surrounding information. The external system 20 provides (transmits) weather information for the environment in which the carbon dioxide capture system 10 is installed. Weather information indicates weather conditions such as sunny, cloudy, rainy, and snowy. Furthermore, the weather information includes not only current weather conditions but also future weather information. Therefore, the control device 17 can acquire weather information from the external system 20. The control device 17 sets the control content for the capture process control according to the weather information. "Future" refers to a predetermined time period, such as several hours later, half a day later, or several days later.

[0031] The following describes a series of control sequences for carbon dioxide recovery performed in the carbon dioxide recovery system 10, including at least an adsorption mode, a scavenging mode, and a desorption / recovery mode. Figure 2 is a flowchart showing the processes performed in the control device 17 to execute the control sequence. Figure 4 is a time chart showing the operation of each part when the processes shown in the flowchart of Figure 2 are performed. Figure 5 is an explanatory diagram for describing the adsorption mode, scavenging mode, and desorption / recovery mode included in the series of control sequences.

[0032] As shown in the flowchart of Figure 2, the control device 17 first performs a decision process for whether to perform the preemptive action in step S10. This decision process for whether to perform the preemptive action will be explained using the flowchart of Figure 3. The decision process for whether to perform the preemptive action is a process for determining whether or not to execute the preemptive action mode based on weather information. The preemptive action mode is a mode in which the control content of the recovery process control is set and executed in anticipation of future weather conditions. Furthermore, the preemptive action mode is a mode in which the recovery process control is executed in advance based on future weather conditions, that is, in conjunction with future weather conditions. The decision process for whether to perform the preemptive action can also be called a mode determination process.

[0033] In step S11, surrounding information is acquired (information acquisition step). The control device 17 acquires weather information as surrounding information via the communication device 172. The control device 17 acquires weather information including current weather conditions and future weather conditions in order to determine whether to switch to the proactive mode or continue in the current normal mode.

[0034] In step S12, it is determined whether or not the pre-emptive conditions are met (control setting step). The control device 17 determines whether or not the pre-emptive conditions are met based on the current weather conditions and future weather conditions of the acquired weather information. If the control device 17 determines that the current weather conditions and future weather conditions will have an impact on carbon dioxide capture, it determines that the pre-emptive conditions are met and proceeds to step S13. If the control device 17 determines that the current weather conditions and future weather conditions will not have an impact on carbon dioxide capture, it determines that the pre-emptive conditions are not met and proceeds to step S14.

[0035] As shown in Figure 13, the impact on carbon dioxide capture differs depending on the current and future weather conditions. For example, if it is sunny now and will remain sunny, there can be no impact. In this case, the control device 17 determines that the prerequisite condition is not met and proceeds to step S14. In other words, the control device 17 determines that it is in normal operating mode (M0). On the other hand, if it is raining now and will remain sunny, there can be an impact. In such cases, the control device 17 determines that the prerequisite condition is met and proceeds to step S13.

[0036] In step S14, the current mode is continued (control setting step). The control device 17 pre-sets the control content of the recovery process control so that the current mode is continued (normal operation mode). In this case, the control device 17 pre-sets the control content of the recovery process control so that the control sequence is executed considering the balance between the amount of carbon dioxide recovered and the energy recovered.

[0037] As shown in Figure 15, the control device 17 sets the control content of the recovery process control so that, for example, the target rate of carbon dioxide adsorption is 80% and the target rate of desorption / recovery is 70%. The target rate of carbon dioxide adsorption (adsorption target rate) is a ratio to the upper limit of the amount of carbon dioxide that can be adsorbed, as shown in Figure 15(a). By setting the adsorption target rate, the target adsorption time can be determined from the relationship between the cumulative amount of carbon dioxide adsorbed and the adsorption time in Figure 15(a). On the other hand, the target rate of desorption / recovery (recovery target rate) is a ratio to the upper limit of the amount of carbon dioxide adsorbed on the electrochemical cell, as shown in Figure 15(b). By setting the recovery target rate, the target desorption / recovery time can be determined from the relationship between the amount of carbon dioxide recovered and the desorption / recovery time in Figure 15(b). Therefore, as part of the control content of the recovery process control, the control device 17 sets the application time of the adsorption potential and the application time of the desorption potential so that it operates while considering the balance between the amount of carbon dioxide recovered and the energy recovered. The adsorption potential corresponds to the first potential. The desorption potential corresponds to the second potential. The application time of the adsorption potential can also be called the adsorption mode execution time. The application time of the desorption potential can also be called the recovery mode execution time.

[0038] Furthermore, the recovered energy is the energy required to recover carbon dioxide. It can also be described as the energy consumed by executing the control sequence. Additionally, the recovered energy includes the energy required to power the electrochemical cell and the energy required to drive the pump 13. The adsorption time and desorption / recovery time in the normal operating mode can also be considered reference times.

[0039] In step S13, the system switches to the preemptive mode (control setting step). For example, the control device 17 sets the switch to the preemptive mode. More specifically, the control device 17 selects (determines) one of several preemptive modes M1 to M3. In other words, even if it is considered that there will be an impact, it is preferable to set the recovery process control to different control content depending on the weather conditions. To put it another way, as shown in Figure 13, there are multiple preemptive modes depending on the weather conditions. For example, if it is currently raining and will be sunny in the future, the system determines to switch to the first preemptive mode (M1). If it is currently raining and will continue to rain, the system determines to switch to the second preemptive mode (M2). If it is currently sunny and will rain in the future, the system determines to switch to the third preemptive mode (M3). For example, the control device 17 stores the switching information indicating the determined preemptive mode in a storage device 171 or the like.

[0040] The decision process for prior implementation may be performed only at predetermined times. The control device 17 may decide to implement the prior mode within a single day, or within a week or several days. The control device 17 may also perform the decision at times such as when the control sequence starts operating or when the user switches to the prior mode. Furthermore, the control device 17 may perform the decision periodically. Periodically means, for example, at a fixed time every day, every few hours, or every few days. The control device 17 may also perform the decision at multiple predetermined times throughout the day. The start of operation can also be said to be the start of execution of the control sequence.

[0041] Let's return to the explanation of the flowchart in Figure 3. In step S20, it is determined whether or not the system is in pre-emptive mode. The control device 17 determines whether or not it has set up a switch to pre-emptive mode in the pre-emptive execution determination process. The control device 17 can make this determination, for example, based on the switching information in the storage device 171. If the storage device 171 has switching information indicating one of the pre-emptive modes M1 to M3 stored in it, the control device 17 determines that the system is in pre-emptive mode and proceeds to step S30. If the storage device 171 does not have switching information stored in it, the control device 17 determines that the system is not in pre-emptive mode and proceeds to step S40.

[0042] In step S30, the adsorption target rate is changed. The control device 17 changes the adsorption target rate according to the selected pre-emptive mode. By changing the adsorption target rate, the control device 17 pre-sets the control content of the recovery process control.

[0043] If the control device 17 determines that it is in the first preemptive mode, it can be considered meteorological information indicating that future weather conditions are suitable for carbon dioxide capture. In this case, the control device 17 pre-sets the control content of the capture process control to increase the amount of carbon dioxide captured compared to the current level. As part of the control content of the capture process control, the control device 17 sets the application time of the adsorption potential to a longer period than the current time in order to increase the amount of carbon dioxide captured compared to the current level. As shown in Figure 14, for example, the application time of the adsorption potential is increased by changing the adsorption target rate from 60% to 100%.

[0044] On the other hand, if the control device 17 determines that it is in the third preemptive mode, it can be considered meteorological information indicating that future weather conditions are not suitable for carbon dioxide capture. In this case, the control device 17 pre-sets the control content of the capture process control to reduce the energy required for carbon dioxide capture compared to the current state. As part of the control content of the capture process control, the control device 17 sets the application time of the adsorption potential to a shorter time than the current time in order to reduce the energy required for carbon dioxide capture compared to the current state. As shown in Figure 14, for example, the application time of the adsorption potential is shortened by changing the adsorption target rate from 100% to 60%.

[0045] Furthermore, if the control device 17 determines that it is in the second preemptive mode, this can be considered meteorological information indicating that future weather conditions will continue to be unsuitable for carbon dioxide capture. In this case, the control device 17 operates in a manner that suppresses the energy required for carbon dioxide capture and pre-sets the control content of the capture process control to increase the amount of carbon dioxide captured when the weather improves. As part of the control content of the capture process control, the control device 17 sets the application time of the adsorption potential to be kept relatively short in order to suppress the energy required for carbon dioxide capture. As shown in Figure 14, for example, the application time of the adsorption potential is fixed to a short time by maintaining the adsorption target rate at 60%. Here, "short time" refers to a time shorter than the reference time.

[0046] In step S40, the control device 17 starts the adsorption mode, which is the first operating mode in a series of control sequences. In this adsorption mode, as shown in Figure 4, the flow path valve 11 is opened to allow the carbon dioxide-containing mixed gas to be introduced into the recovery unit 12. If a blower 19 is provided, the blower 19 is driven to allow more of the mixed gas to be introduced into the recovery unit 12. If the pump 13 also serves the role of the blower 19, the pump 13 is driven to suck in the mixed gas, drawing it into the recovery unit 12 from the outside. In this case, since the pump 13 is driven simply to suck in the mixed gas from the outside, the energy required for this suction is less than the energy required to drive the pump for vacuuming in the scavenging mode and desorption / recovery mode described later.

[0047] Furthermore, in adsorption mode, as shown in Figure 4, an adsorption potential is applied between the working electrode and the counter electrode of the electrochemical cell of the recovery unit 12, enabling the carbon dioxide adsorbent of the working electrode to adsorb carbon dioxide. In other words, the control device 17 performs power application control to apply the adsorption potential. In addition, in adsorption mode, as shown in Figure 4, the flow path switching valve 14 is controlled to connect the downstream piping of the pump 13 to the outside.

[0048] Through the control of the flow control valve 11, the electrochemical cells of the recovery unit 12, and the flow control valve 14, in the adsorption mode, as shown by the dotted arrow in Figure 5(a), the mixed gas containing carbon dioxide (atmospheric gas) passes through the flow control valve 11 and enters the recovery unit 12. Once inside the recovery unit 12, the mixed gas is adsorbed by multiple electrochemical cells, removing the carbon dioxide. The mixed gas from which the carbon dioxide has been removed passes through the pump 13 and is guided by the flow control valve 14 to a flow pipe leading to the outside, and is released to the outside through that flow pipe.

[0049] In step S50, the control device 17 determines whether the adsorption mode execution time has elapsed. The adsorption mode execution time is not constant and changes for several reasons, including estimating the maximum adsorption amount of the electrochemical cell in the map creation process described later, and the maximum adsorption time which is the adsorption mode execution time required to obtain that maximum adsorption amount, and optimizing the carbon dioxide recovery amount and energy consumption when the carbon dioxide adsorption performance of the electrochemical cell changes due to environmental changes or aging. This changing adsorption mode execution time is set by the control device 17, for example, in step S30. In step S50, it is determined whether the set adsorption mode execution time has elapsed. In this embodiment, the maximum adsorption amount is used as the target carbon dioxide adsorption amount. Therefore, below, the maximum adsorption amount will also be referred to as the target carbon dioxide adsorption amount. The maximum adsorption amount can also be called the target adsorption amount.

[0050] In the determination process in step S50, if it is determined that the set adsorption mode execution time has elapsed, the process proceeds to step S60. On the other hand, if it is determined that the set adsorption mode execution time has not elapsed, the determination process in step S50 is repeatedly executed until the adsorption mode execution time has elapsed.

[0051] In step S60, the adsorption mode termination process is executed. Specifically, the control device 17 closes the flow path valve 11 to block the mixed gas flowing into the recovery unit 12 from the outside. If a blower 19 is provided, the control device 17 also stops the operation of the blower 19. The control device 17 also resets the count value of the counter that counts the adsorption mode execution time.

[0052] Thus, the control device 17 applies an adsorption potential to the carbon dioxide adsorbent material so that it adsorbs carbon dioxide when the adsorption mode is being executed. The control device 17 applies the adsorption potential only for the duration of the adsorption mode, which corresponds to the target amount of carbon dioxide adsorbed.

[0053] The adsorption mode execution time can be obtained from the adsorption amount change map data. The target carbon dioxide adsorption amount can be obtained from the recovery amount change map data. The control device 17 obtains the target carbon dioxide adsorption amount associated with the carbon dioxide recovery amount detected via the sensor 15 from the recovery amount change map data. As shown in Figure 8, the target carbon dioxide adsorption amount in the recovery amount change map data is a correlation value that correlates with the carbon dioxide recovery amount detected via the sensor 15. Therefore, it can be said that the control device 17 obtains the correlation value that correlates with the carbon dioxide recovery amount detected via the sensor 15 as the target carbon dioxide adsorption amount. Then, the control device 17 obtains the adsorption mode execution time associated with the target carbon dioxide adsorption amount from the adsorption amount change map data. In the example in Figure 6, for example, if the target carbon dioxide adsorption amount is set to 80 [g], the adsorption mode execution time will be 80 [s].

[0054] As shown in Figure 7, the target carbon dioxide adsorption amount is updated according to the amount of carbon dioxide recovered detected via sensor 15. Also, as shown in Figure 6, the adsorption mode execution time changes each time the target carbon dioxide adsorption amount is updated. The target carbon dioxide adsorption amount may be stored in a memory device or the like as an initial calculation threshold or an update threshold.

[0055] In step S70, the control device 17 starts the scavenging mode, which is the second operating mode of the series of control sequences. In this scavenging mode, the flow path valve 11 remains closed, as shown in Figure 4. The adsorption potential applied between the working electrode and the counter electrode of the electrochemical cell of the recoverer 12 is maintained. Communication between the downstream piping of the pump 13 and the outside is also maintained by the flow path switching valve 14.

[0056] In scavenging mode, the pump 13 is started to operate as shown in Figure 4. As described above, the flow path valve 11 is closed, so the recovery unit 12 is sealed upstream of the pump 13. When the pump 13 is started in this state, the residual mixed gas from which carbon dioxide has been removed, which remains in the sealed recovery unit 12, is sucked out of the recovery unit 12 and released to the outside. This allows the residual mixed gas in the recovery unit 12 to be scavenged.

[0057] Furthermore, since the recovery unit 12 upstream of the pump 13 is sealed, the residual mixed gas in the recovery unit 12 is scavenged by vacuuming with the pump 13. For this reason, if the pump 13 also functions as a blower 19, the pump 13 continues to run, but its output is increased compared to the intake mode when the scavenging mode is initiated.

[0058] Through the control of the flow path switching valve 11, the electrochemical cell of the recovery unit 12, the pump 13, and the flow path switching valve 14, in the scavenging mode, as shown by the dotted arrow in Figure 5(b), the residual mixed gas from which carbon dioxide has been removed in the recovery unit 12 passes through the pump 13, is guided by the flow path switching valve 14 to a flow path piping leading to the outside, and is released to the outside through that flow path piping.

[0059] In step S80, the control device 17 determines whether the scavenging mode execution time has elapsed. This scavenging mode execution time is predetermined to be sufficient time to scavenge the residual mixed gas in the recovery unit 12.

[0060] In the determination process in step S80, if it is determined that a predetermined scavenging mode execution time has elapsed, the process proceeds to step S90. On the other hand, if it is determined that the set scavenging mode execution time has not elapsed, the determination process in step S80 is repeatedly executed until the scavenging mode execution time has elapsed.

[0061] In step S90, the scavenging mode termination process is executed. Specifically, the control device 17 resets the count value of the counter that counts the scavenging mode execution time.

[0062] Step S100 is the same as step S20. In step S110, the recovery target rate is changed. The control device 17 changes the recovery target rate according to the selected pre-emptive mode. By changing the recovery target rate, the control device 17 pre-sets the control content of the recovery process control.

[0063] When the control device 17 determines that it is in the first preemptive mode, it can be considered meteorological information indicating that future weather conditions are suitable for carbon dioxide capture. In this case, the control device 17 pre-sets the control content of the capture process control to increase the amount of carbon dioxide captured compared to the current level. Therefore, as part of the control content of the capture process control, the control device 17 sets the application time of the desorption potential to a longer period than the current time in order to increase the amount of carbon dioxide captured compared to the current level. As shown in Figure 14, for example, the application time of the desorption potential is increased by changing the capture target rate from 50% to 90%.

[0064] On the other hand, if the control device 17 determines that it is in the third preemptive mode, it can be considered meteorological information indicating that future weather conditions are not suitable for carbon dioxide capture. In this case, the control device 17 pre-sets the control content of the capture process control to reduce the energy required for carbon dioxide capture compared to the current state. Therefore, as part of the control content of the capture process control, the control device 17 sets the application time of the desorption potential to a shorter time than the current time in order to reduce the energy required for carbon dioxide capture compared to the current state. As shown in Figure 14, for example, the application time of the desorption potential is shortened by changing the capture target rate from 90% to 50%.

[0065] Furthermore, if the control device 17 determines that it is in the second preemptive mode, this can be considered meteorological information indicating that future weather conditions will continue to be unsuitable for carbon dioxide capture. In this case, the control device 17 operates in a way that suppresses the energy required for carbon dioxide capture and pre-sets the control content of the capture process control to increase the amount of carbon dioxide captured when the weather improves. Therefore, as part of the control content of the capture process control, the control device 17 sets the application time of the desorption potential to be kept relatively short in order to suppress the energy required for carbon dioxide capture. As shown in Figure 14, for example, the application time of the desorption potential is fixed to a short time by maintaining the capture target rate at 50%. Here, "short time" means a time shorter than the reference time.

[0066] In this embodiment, sunny, cloudy, rainy, and snowy are used as examples of weather information. However, as shown in Figure 12, other weather conditions that affect carbon dioxide capture include humidity, temperature, precipitation, and snow depth. For example, when humidity is high, the concentration of carbon dioxide in the atmosphere decreases. Therefore, the amount of carbon dioxide captured by the carbon dioxide capture system 10 decreases. Also, when humidity is high, the energizing time in the adsorption mode and desorption / capture mode increases, meaning the execution time of the adsorption mode and desorption / capture mode increases, and the energy consumption for capturing carbon dioxide increases. When the temperature is low, the current consumption increases. Therefore, the energy consumption for capturing carbon dioxide by the carbon dioxide capture system 10 increases. Therefore, the control device 17 may determine whether or not to switch to the pre-emptive mode based on humidity, temperature, precipitation, snow depth, etc.

[0067] In step S120, the control device 17 starts the desorption / recovery mode, which is the third operating mode of the series of control sequences (acquisition step). In this desorption / recovery mode, the flow path valve 11 is kept closed, as shown in Figure 4. The pump 13 is also driven with the same drive output as in the scavenging mode, as it sucks up the carbon dioxide desorbed from the electrochemical cell in a state closer to a vacuum than atmospheric pressure.

[0068] Meanwhile, between the working electrode and the counter electrode of the electrochemical cell of the recovery unit 12, a desorption potential is applied that causes electrons to be released from the working electrode, enabling the carbon dioxide adsorbent on the working electrode to desorb the carbon dioxide adsorbed therefrom. In other words, the control device 17 performs power application control to apply the desorption potential. Furthermore, in the desorption / recovery mode, as shown in Figure 4, the flow path switching valve 14 is controlled to connect the piping downstream of the pump 13 to the CO2 recovery tank 16.

[0069] Through the control of the flow path switching valve 11, the electrochemical cell of the recovery unit 12, the pump 13, and the flow path switching valve 14, in the desorption / recovery mode, as shown by the dotted arrow in Figure 5(c), carbon dioxide desorbed from the electrochemical cell passes through the pump 13 and is guided by the flow path switching valve 14 to a flow path pipe leading to the CO2 recovery tank 16, where it is accumulated. At this time, the concentration and flow rate of carbon dioxide flowing through the flow path pipe toward the CO2 recovery tank 16 are detected by the sensor 15. Based on the detection results of the sensor 15, the control device 17 can calculate the amount of carbon dioxide recovered in the CO2 recovery tank 16 by executing a series of control sequences. The concentration of carbon dioxide flowing through the flow path pipe toward the CO2 recovery tank 16 is usually close to 100%. For this reason, a sensor 15 capable of detecting the flow rate of carbon dioxide may be used.

[0070] Furthermore, the desorption / recovery mode does not necessarily perform carbon dioxide desorption and recovery simultaneously. Instead, carbon dioxide may be desorbed from the electrochemical cell first, and the recovery of the desorbed carbon dioxide may begin after a predetermined time has elapsed since the desorption. In other words, the desorption mode and the recovery mode can be separated, and the start time of the recovery mode can be delayed compared to the start time of the desorption mode, thereby shortening the execution time of the recovery mode. In this case, the pump 13 is temporarily stopped at the start of the desorption mode. With the pump 13 stopped, a desorption potential is applied between the working electrode and the counter electrode of the electrochemical cell to desorb carbon dioxide from the carbon dioxide adsorbent at the working electrode. After a predetermined time has elapsed since the start of the desorption mode and a certain amount of carbon dioxide desorption has progressed, the recovery mode is started and the pump 13 is restarted. As a result, the pump 13 only needs to be driven in the recovery mode, making it possible to drive the pump 13 efficiently. However, even during the recovery mode in which the pump 13 is driven, a desorption potential is applied between the working electrode and the counter electrode of the electrochemical cell, and the desorption of carbon dioxide from the electrochemical cell continues.

[0071] In step S130, the control device 17 determines whether the desorption / recovery mode execution time or the recovery mode execution time (hereinafter, the desorption / recovery mode will be referred to as the recovery mode) has elapsed (acquisition step). The recovery mode execution time is not constant and changes for reasons such as optimizing the amount of carbon dioxide recovered and the energy consumed when the carbon dioxide adsorption performance of the electrochemical cell changes due to environmental changes or aging. This changing recovery mode execution time is set by the control device 17, for example, in step S110. In step S130, it is determined whether the set recovery mode execution time has elapsed.

[0072] In the determination process of step S130, if it is determined that the set recovery mode execution time has elapsed, the process proceeds to step S140. On the other hand, if it is determined that the set recovery mode execution time has not elapsed, the determination process of step S130 is repeatedly executed until the recovery mode execution time has elapsed. In this way, the control device 17 applies a desorption potential to the carbon dioxide adsorbent material to desorb the carbon dioxide it has adsorbed during the execution of the recovery mode in which carbon dioxide is recovered. The control device 17 applies the desorption potential only for the duration of the recovery mode execution time corresponding to the target amount of carbon dioxide adsorbed. The recovery mode execution time corresponds to the recovery time.

[0073] In step S140, the recovery mode termination process is executed (acquisition step). Specifically, the control device 17 opens the flow path valve 11 to connect the recovery unit 12 to the outside. The control device 17 stops applying the desorption potential to the electrochemical cell. The control device 17 stops driving the pump 13. The control device 17 switches the flow path switching valve 14 to connect the downstream piping of the pump 13 to the outside. Furthermore, the control device 17 also resets the count value of the counter that counts the recovery mode execution time.

[0074] It is assumed that the carbon dioxide adsorption performance of the electrochemical cell described above will change due to aging and other factors. However, it is not possible to directly detect the upper limit of carbon dioxide that the electrochemical cell can adsorb. Therefore, it cannot be ruled out that the adsorption mode may continue even if the carbon dioxide adsorption capacity of the electrochemical cell has reached its upper limit, or that the recovery mode may continue even if the recovery of carbon dioxide released from the electrochemical cell has substantially ended.

[0075] Thus, in an attempt to maximize the amount of carbon dioxide recovered, for example, if the adsorption mode is always run for a sufficient time to adsorb the upper limit of the amount of carbon dioxide that the electrochemical cell can adsorb, and the recovery mode is run for a sufficient time to recover all the carbon dioxide that the electrochemical cell has adsorbed, then the carbon dioxide recovery system 10 may consume an excessive amount of energy relative to the amount of carbon dioxide recovered.

[0076] Therefore, the carbon dioxide capture system 10 according to this embodiment has a configuration in which the storage device of the control device 17 stores adsorption amount change map data and recovery amount change map data.

[0077] The following provides a detailed explanation of the adsorption amount change map data and the recovery amount change map data. First, we will explain the map creation process for creating the adsorption amount change map data based on the flowchart in Figure 9.

[0078] When the control device 17 performs map creation processing, it executes multiple adsorption modes at different execution times (elapsed time) and detects the amount of carbon dioxide recovered in the multiple recovery modes executed in accordance with each adsorption mode via the sensor 15. For example, Figure 4 shows an example in which three adsorption modes are executed at different execution times. Note that the number of times the multiple adsorption modes are executed may be as few as two.

[0079] In Figure 4, the execution time of the first adsorption mode is set to be relatively short so that the amount of carbon dioxide adsorbed by the electrochemical cell does not reach its upper limit. Therefore, the amount of carbon dioxide recovered when the recovery mode corresponding to the first adsorption mode is executed is less than the upper limit of the carbon dioxide adsorbed by the electrochemical cell.

[0080] The execution time for the second adsorption mode is relatively long, and it is set so that the amount of carbon dioxide adsorbed by the electrochemical cell reaches approximately its upper limit. Therefore, the amount of carbon dioxide recovered when the recovery mode corresponding to the second adsorption mode is executed is approximately equal to the upper limit of the carbon dioxide adsorption capacity of the electrochemical cell.

[0081] The execution time for the third adsorption mode is the longest, and it is set so that the adsorption mode continues for a certain period even after the carbon dioxide adsorption capacity of the electrochemical cell reaches its upper limit. Therefore, the amount of carbon dioxide recovered when the recovery mode corresponding to the third adsorption mode is executed is equal to the upper limit of the carbon dioxide adsorption capacity of the electrochemical cell.

[0082] Based on the sensor detection results during the execution of the multiple adsorption modes described above, and the multiple recovery modes corresponding to each adsorption mode, the maximum adsorption amount of the electrochemical cell and the maximum adsorption time, which is the execution time of the adsorption mode required to obtain that maximum adsorption amount, are estimated. Specific examples of the method for estimating the maximum adsorption amount and maximum adsorption time of the electrochemical cell are explained with reference to Figures 10(a), (b), and (c).

[0083] In step S200, it is determined whether or not the map creation criteria are met. The control device 17 determines that it is possible to plot the amount of carbon dioxide recovered in the three recovery modes described above for one adsorption amount change map data, and that there is a maximum value of carbon dioxide recovered that is not plotted on the same straight line. Note that tolerances may be included on the same straight line. If the control device 17 determines that the map creation criteria are met, it proceeds to step S210; if it determines that they are not met, it proceeds to step S240.

[0084] In step S240, a retry is performed. The control device 17 executes the adsorption mode again and detects the amount of carbon dioxide recovered in the recovery mode, which is executed in conjunction with the adsorption mode, via the sensor 15. At this time, the control device 17 sets the execution time of the adsorption mode to be longer than the previous time (third time).

[0085] Then, the control device 17 performs S200 using the amount of carbon dioxide recovered in the retry. The control device 17 repeatedly executes steps S200 and S240 until it determines YES in step S200. If the control device 17 executes step S240, in step S220 it adopts the amount of carbon dioxide recovered in the retry as the target amount of carbon dioxide adsorbed.

[0086] In step S210, the slope is calculated. Figure 10(a) is a graph showing the amount of carbon dioxide adsorbed by the electrochemical cell and the execution time of the first adsorption mode, based on the amount of carbon dioxide recovered when the recovery mode corresponding to the first adsorption mode is executed. Note that the amount of carbon dioxide adsorbed by the electrochemical cell can be considered equal to the amount of carbon dioxide recovered. As described above, the execution time of the first adsorption mode is relatively short and set so that the amount of carbon dioxide adsorbed by the electrochemical cell does not reach the upper limit. Therefore, as shown in Figure 10(a), based on the amount of carbon dioxide adsorbed by the electrochemical cell during the execution of the first adsorption mode, the increasing gradient line (slope) can be determined by assuming that the amount of carbon dioxide adsorbed increases linearly as the execution time of the adsorption mode increases.

[0087] In step S220, the target carbon dioxide adsorption amount is calculated. Figure 10(b) is a graph showing the carbon dioxide adsorption amount of each electrochemical cell and the execution time of the second and third adsorption modes, based on the amount of carbon dioxide recovered when the recovery modes corresponding to the second and third adsorption modes are executed. As described above, the execution time of the second adsorption mode is relatively long, set so that the carbon dioxide adsorption amount of the electrochemical cell reaches almost the upper limit, and the execution time of the third adsorption mode is the longest, set so that the adsorption mode is executed for a certain period of time even after the carbon dioxide adsorption amount of the electrochemical cell has reached the upper limit. Therefore, as shown in Figure 10(b), an upper limit line for the carbon dioxide adsorption amount of the electrochemical cell can be determined based on the carbon dioxide adsorption amount of the electrochemical cell due to the execution of the second and third adsorption modes. The carbon dioxide adsorption amount corresponding to the upper limit line becomes the target carbon dioxide adsorption amount, which is the maximum adsorption amount that can be adsorbed.

[0088] Furthermore, the upper limit of the carbon dioxide adsorption capacity of the electrochemical cell may be determined based on the amount of carbon dioxide adsorbed by the electrochemical cell obtained through the execution of one adsorption mode and the corresponding recovery mode.

[0089] In step S230, as shown in Figure 10(c), the adsorption time, which is the maximum adsorption time and is the adsorption mode execution time required to obtain the maximum adsorption amount, can be determined from the intersection of the increasing gradient line in Figure 10(a) and the upper limit line in Figure 10(b).

[0090] In this way, the control device 17 estimates the maximum adsorption amount of the electrochemical cell as the target carbon dioxide adsorption amount based on the carbon dioxide recovery amount detected in multiple recovery modes, and also estimates the adsorption time required to obtain the maximum adsorption amount, thereby creating adsorption amount change data. The control device 17 then stores the created adsorption amount change map data in a storage device. The adsorption amount change map data is updated with the target carbon dioxide adsorption amount and adsorption time due to factors such as the aging of the electrochemical cell.

[0091] Next, the process for setting the target carbon dioxide adsorption amount in the recovery amount change map data will be explained based on the flowchart in Figure 11. The control device 17 determines whether to maintain or update the target carbon dioxide adsorption amount at its current value by executing the flowchart in Figure 11.

[0092] As shown in Figures 7 and 8, the recovery amount change map data is associated with different target carbon dioxide adsorption amounts for each cycle number of multiple control sequences. Here, we use an example where the target carbon dioxide adsorption amount is updated every 10 cycles. In addition, the recovery amount change map data is associated with the carbon dioxide recovery amount (carbon dioxide monitor value) detected via sensor 15 and the target carbon dioxide adsorption amount.

[0093] The initial calculated threshold is 1 cycle This is the initial target carbon dioxide adsorption amount adopted from cycle 1 to 10. The update threshold is the updated target carbon dioxide adsorption amount. The update threshold is the target carbon dioxide adsorption amount assumed due to aging degradation of the electrochemical cell, etc. Therefore, the update threshold is a smaller value than the initially calculated threshold. Also, the update threshold decreases as the number of cycles increases.

[0094] Furthermore, the area between the initial calculated threshold and the updated threshold, and between the updated threshold and the next updated threshold, constitutes the adsorption amount retention region. The adsorption amount retention region is the area that maintains the current target carbon dioxide adsorption amount. On the other hand, the area outside the adsorption amount retention region is the adsorption amount update region. The adsorption amount update region is the area where the target carbon dioxide adsorption amount is updated from the current value.

[0095] In step S300, it is determined whether the recovered amount is within the adsorption amount retention range. The control device 17 determines whether the carbon dioxide monitor value as the recovered amount is within the adsorption amount retention range. If the control device 17 determines that the carbon dioxide monitor value is within the adsorption amount retention range, it proceeds to step S310; if it determines that it is not within the adsorption amount retention range, it proceeds to step S320.

[0096] In step S310, the target carbon dioxide adsorption amount is maintained. The control device 17 maintains the current target carbon dioxide adsorption amount. The control device 17 maintains the current target carbon dioxide adsorption amount when the carbon dioxide monitor value is as shown by the dot hatching in Figure 8.

[0097] In step S320, the target carbon dioxide adsorption amount is updated. The control device 17 updates the current target carbon dioxide adsorption amount to the new target carbon dioxide adsorption amount. The control device 17 updates the target carbon dioxide adsorption amount when the carbon dioxide monitor value is as shown by the hatched area in Figure 8.

[0098] In step S330, the target carbon dioxide adsorption amount is set. The control device 17 sets the current target carbon dioxide adsorption amount or the updated target carbon dioxide adsorption amount as the target carbon dioxide adsorption amount when setting the adsorption mode execution time. In this way, the control device 17 sets the target carbon dioxide adsorption amount from the carbon dioxide recovery amount.

[0099] As described above, the carbon dioxide capture system 10 is equipped with a control device 17 that detects the amount of carbon dioxide recovered from the capture device 12 to the carbon dioxide capture tank 16 via a sensor 15. The control device 17 then acquires a correlation value that correlates with the amount of carbon dioxide recovered, which is the result of detection via the sensor 15, as the target carbon dioxide adsorption amount. Therefore, the carbon dioxide capture system 10 is able to determine the target carbon dioxide adsorption amount.

[0100] Furthermore, the control device 17 executes multiple adsorption modes and determines the target carbon dioxide adsorption amount using adsorption amount change map data created from the carbon dioxide recovery amount detected via the sensor 15 during the multiple recovery modes executed in accordance with each adsorption mode. The control device 17 then applies the adsorption potential only during the duration of the adsorption mode execution obtained from the adsorption amount change map data. Therefore, the control device 17 can apply the adsorption potential only for the time necessary to obtain the maximum adsorption amount. In other words, the control device 17 can suppress the application of the adsorption potential for a longer time than necessary to obtain the maximum adsorption amount. Thus, the control device 17 can appropriately control the application time of the adsorption potential to obtain the maximum adsorption amount.

[0101] Furthermore, the control device 17 updates the adsorption amount change map data according to the amount of carbon dioxide recovered detected via the sensor 15. Therefore, even if the electrochemical cell deteriorates over time, the optimal target amount of carbon dioxide adsorption can be determined, and the application time of the adsorption potential can be appropriately controlled.

[0102] Furthermore, the carbon dioxide capture system 10 sets the control content for the capture process in accordance with weather information. Therefore, the carbon dioxide capture system 10 can perform optimal capture process control according to weather conditions. It can also be said that the carbon dioxide capture system 10 can perform optimal capture process control in advance of changes in weather conditions.

[0103] In other words, the carbon dioxide capture system 10 executes a control sequence based on acquired weather information to capture more carbon dioxide when conditions are favorable for capture. Conversely, it executes a control sequence to suppress the energy used for capture when conditions are unfavorable for capture. Therefore, the carbon dioxide capture system 10 can efficiently capture carbon dioxide according to weather conditions. Furthermore, the carbon dioxide capture system 10 can efficiently consume the energy used for capture according to weather conditions.

[0104] Next, the processing operation of a modified example will be described using Figures 16 and 17. The modified carbon dioxide recovery system 10 has the same configuration as the embodiment described above. Furthermore, the modified carbon dioxide recovery system 10 performs the same carbon dioxide recovery process as the embodiment described above. Here, we will mainly describe the differences from the embodiment described above.

[0105] The carbon dioxide capture system 10 is expected to shut down quickly while suppressing carbon dioxide leakage in the event of emergencies such as bad weather or disasters. However, as the scale of the carbon dioxide capture system 10 increases, the adsorption and desorption times become longer. Also, if the carbon dioxide capture system 10 stops midway, it is possible that the adsorbed high-concentration carbon dioxide will leak out. Therefore, the modified carbon dioxide capture system 10 aims to stop operation in advance of an emergency in response to surrounding information. In other words, the modified carbon dioxide capture system 10 uses surrounding information to stop operation before an emergency occurs. When the system is stopped, the blower 19 is off, the flow path switching valve 11 is closed, the capturer 12 (electrochemical cell) is powered off, the pump 13 is off, and the flow path switching valve 14 is in the stop state for removal.

[0106] In the modified version, as an example of surrounding information, at least one of the weather information and warning information for the environment in which the carbon dioxide capture system 10 is installed is adopted. Here, the weather information is information indicating meteorological conditions such as precipitation and wind speed. The warning information is information indicating natural disasters such as earthquakes and tsunamis. In addition, warning information such as special heavy rain warnings, special heavy snow warnings, special wind warnings, special wind and snow warnings, special wave warnings, and special storm surge warnings can also be adopted.

[0107] The surrounding information for the modified configuration is information used to determine whether or not to stop the operation of the carbon dioxide capture system 10, or whether or not it is an emergency situation requiring its operation to be stopped. Furthermore, the stop decision information includes not only current weather conditions and warning information, but also future weather information and warning information. Hereafter, weather information and warning information will be collectively referred to as stop decision information. Note that weather information and warning information can also be called emergency information. Stopping the operation of the carbon dioxide capture system 10 means putting each component into the stop state described above, which can also be described as stopping the execution of the control sequence or stopping the capture process control.

[0108] The external system 20 provides (transmits) stop decision information. Therefore, the control device 17 can obtain stop decision information from the external system 20. The control device 17 sets the control content of the recovery process control according to the stop decision information. The control device 17 sets the stop process of the recovery process control as the control content of the recovery process control. In other words, the control device 17 decides whether or not to stop the operation of the carbon dioxide recovery system 10 according to the stop decision information.

[0109] In this modified example, there are two stopping modes for the stopping process. The two stopping modes are an immediate stopping mode, which immediately stops the recovery process control, and a continuous stopping mode, which stops the recovery process control after the recovery to the carbon dioxide recovery tank 16 has been completed. If it is determined to stop the operation of the carbon dioxide recovery system 10 before starting the recovery process control, the recovery process control will not be started. In other words, each component will not be operated.

[0110] Here, the stop determination process shown in Figure 16 will be explained. The control device 17 starts the flowchart in Figure 16 when operation begins. The control device 17 may also start the flowchart in Figure 16 periodically, for example, at 5:00, 11:00, and 17:00 every day. Furthermore, the control device 17 may start the flowchart in Figure 16 when it acquires stop determination information. In this case, the control device 17 executes step S12a without executing step S11a.

[0111] In step S11a, in step S11, surrounding information is acquired (information acquisition step). The control device 17 acquires stop decision information as surrounding information via the communication device 172. The control device 17 Immediately To determine whether to switch to time-based stop mode or continuous stop mode, future stop decision information is acquired.

[0112] In step S12a, it is determined whether or not the continuous stop mode applies (control setting step). The control device 17 determines whether or not the continuous stop mode applies based on the acquired future stop judgment information. If the control device 17 determines that the continuous stop mode applies, it proceeds to step S13a; if it determines that the continuous stop mode does not apply, it proceeds to step S14a.

[0113] To elaborate, first, the control device 17 determines whether the stop judgment information satisfies the stop conditions for the recovery process control. The stop conditions include, for example, rainfall exceeding a predetermined value, wind speed exceeding a predetermined value, or the occurrence of any of the above-mentioned alarms. If the stop judgment information satisfies the stop conditions, the control device 17 sets one of two stop modes according to the processing stage of the recovery process control, from carbon dioxide adsorption to recovery in the carbon dioxide recovery tank 16. In other words, the control device 17 sets one of two stop modes according to which processing stage is currently being executed, from the start of the adsorption mode to the end of the recovery mode.

[0114] In this case, as shown in Figure 17, the control device 17 determines that the current processing stage does not fall under the continuous stop mode, i.e., it is the immediate stop mode, if it is immediately after the start of the adsorption mode or if a certain amount of time has elapsed since the start of the recovery mode. In other words, the control device 17 sets the immediate stop mode as the stop mode if the processing stage is such that the elapsed time since the start of carbon dioxide adsorption is less than a predetermined time, or the elapsed time since the start of carbon dioxide recovery is greater than or equal to a predetermined time. The predetermined time (first predetermined time) compared with the elapsed time since the start of carbon dioxide adsorption is the time during which the carbon dioxide concentration can be considered low. On the other hand, the predetermined time (second predetermined time) compared with the elapsed time since the start of carbon dioxide recovery is the time during which the residual carbon dioxide concentration can be considered low.

[0115] Thus, if the carbon dioxide concentration remaining in the carbon dioxide capture system 10 is considered low, the amount of carbon dioxide leaking from the carbon dioxide capture system 10 will be small even if it is immediately stopped. Therefore, the control device 17 sets the immediate stop mode when the remaining carbon dioxide concentration is considered low. A small amount of carbon dioxide is, for example, an amount that can be considered to have little impact on the natural environment. Therefore, the time during which the remaining carbon dioxide concentration is considered low can be set, for example, based on an amount of carbon dioxide that can be considered to have little impact on the natural environment even if it leaks.

[0116] Furthermore, as shown in Figure 17, the control device 17 determines that the current processing stage corresponds to the continuous stop mode if it falls within the period from the start of the adsorption mode to immediately after the start of the recovery mode. In other words, the control device 17 sets the continuous stop mode as the stop mode if the processing stage is such that the elapsed time from the start of carbon dioxide adsorption is greater than or equal to a predetermined time, and the elapsed time from the start of carbon dioxide recovery is less than a predetermined time. The predetermined time (third predetermined time) compared with the elapsed time from the start of carbon dioxide adsorption is the time during which the carbon dioxide concentration can be considered high. The predetermined time (fourth predetermined time) compared with the elapsed time from the start of carbon dioxide recovery is the time during which the residual carbon dioxide concentration can be considered high.

[0117] Thus, if the carbon dioxide concentration remaining in the carbon dioxide capture system 10 is deemed to be high, there is a risk that an excessive amount of carbon dioxide will leak from the carbon dioxide capture system 10 if it is immediately stopped. Therefore, the control device 17 sets the continuous stop mode if the remaining carbon dioxide concentration is deemed to be high. A high amount of carbon dioxide is, for example, an amount greater than the amount that would leak in the immediate stop mode, or an amount that is considered to have a significant impact on the natural environment. Therefore, the time during which the remaining carbon dioxide concentration is deemed to be high can be set, for example, based on the amount of carbon dioxide that, if leaked, would have a significant impact on the natural environment.

[0118] In step S13a, the system switches to continuous stop mode (control setting step). The control device 17 sets the execution of continuous stop mode. As shown in Figure 17, if the control device 17 sets continuous stop mode when the adsorption mode is being executed, it executes the adsorption mode, scavenging mode, desorption mode, and recovery mode, and when the recovery mode is completed, it sets each component to the stopped state. If the control device 17 sets continuous stop mode when the scavenging mode is being executed, it executes the scavenging mode, desorption mode, and recovery mode, and when the recovery mode is completed, it sets each component to the stopped state. If the control device 17 sets continuous stop mode when the desorption mode is being executed, it executes the desorption mode and recovery mode, and when the recovery mode is completed, it sets each component to the stopped state. If the control device 17 sets continuous stop mode when the recovery mode is being executed, it executes the recovery mode, and when the recovery mode is completed, it sets each component to the stopped state. These stop controls can also be called normal stop controls.

[0119] In this example, the detachment mode and the recovery mode are performed separately. However, as in the above embodiment, the detachment mode and the recovery mode may be performed without separating them.

[0120] In step S14a, the system switches to immediate stop mode (control setting step). The control device 17 sets the execution of immediate stop mode. As shown in Figure 17, if the control device 17 sets immediate stop mode when the suction mode is being executed, it terminates the execution of immediate suction mode. Then, the control device 17 puts each component into a stopped state. Also, if the control device 17 sets immediate stop mode when the recovery mode is being executed, it terminates the execution of immediate recovery mode. Then, the control device 17 puts each component into a stopped state.

[0121] In this way, the control device 17 sets the stop process as the control content of the recovery process control according to the stop decision information. If the stop decision information indicates that there is no need to stop the operation of the carbon dioxide recovery system 10, the control device 17 may terminate the flowchart in Figure 16. In this case, the control device 17 terminates the flowchart in Figure 16 without executing steps S12a to S14a.

[0122] Thus, when the carbon dioxide capture system 10 stops operating because the stop decision information satisfies the stop conditions for the capture process control, it changes the processing content up to the stop operation according to the system's operating state and the carbon dioxide concentration. The system's operating state corresponds to the processing stage by the control device 17. In other words, the carbon dioxide capture system 10 sets the control content of the capture process control according to the stop decision information as peripheral information. Therefore, the carbon dioxide capture system 10 can perform optimal capture process control (stop processing) according to the surrounding conditions.

[0123] In continuous stop mode, the recovery process control is stopped after the recovery of carbon dioxide into the carbon dioxide recovery tank 16 is completed. However, in the event of an emergency, there may not be enough time before the carbon dioxide recovery system 10 is affected, i.e., there may not be enough time to stop the carbon dioxide recovery system 10. Therefore, in continuous stop mode, the control device 17 may perform shortened control to reduce the execution time until recovery into the carbon dioxide recovery tank 16 when the continuous stop mode is set (control setting step). In other words, the control device 17 performs shortened control that reduces the execution time compared to normal stop control.

[0124] For example, in a carbon dioxide capture system 10 equipped with multiple capture units 12, under normal stop control, each capture unit 12 is stopped one by one. On the other hand, under shortened control, all capture units 12 are stopped simultaneously. Furthermore, under shortened control, the suction force of the pump 13 is increased compared to under normal stop control. In addition, under shortened control, the determination value (capture mode execution time) for determining the end of the capture mode is set earlier than under normal stop control. In other words, under shortened control, each component is immediately stopped when the residual carbon dioxide concentration reaches a level where leakage would have little impact on the natural environment. As a result, the carbon dioxide capture system 10 can shorten the time until shutdown, even in continuous stop mode.

[0125] The control device 17 may also predict (obtain) the grace period before the carbon dioxide capture system 10 is affected from the stop decision information. In this case, the control device 17 compares the grace period with the processing time required to bring each component to the stop state from the start of the continuous stop mode. If the processing time is shorter than the grace period, the control device 17 performs normal stop control. The control device 17 may perform shortening control only if the processing time is longer than the grace period.

[0126] While preferred embodiments of the Disclosure have been described above, the Disclosure is not limited to the above embodiments and can be implemented in various ways without departing from the spirit of the Disclosure. The Disclosure also includes various modifications and variations within the scope of equivalents. In addition, while various combinations and forms are shown in the Disclosure, other combinations and forms that include only one, more, or fewer of these elements also fall within the scope and idea of ​​the Disclosure. [Explanation of Symbols]

[0127] 10: Carbon dioxide capture system, 11: Flow control valve, 12: Recovery unit, 13: Pump, 14: Flow switching valve, 15: Sensor, 16: CO2 capture tank, 17: Control device, 19: Blower, 20: External system

Claims

1. A carbon dioxide capture system that recovers carbon dioxide from a mixed gas containing carbon dioxide by an electrochemical reaction, A carbon dioxide capture tank (16) for storing the captured carbon dioxide, An electrochemical cell having a working electrode containing an adsorbent material capable of adsorbing carbon dioxide and a counter electrode paired with the working electrode, and a housing for housing the electrochemical cell, wherein the mixed gas is supplied to the inside of the housing, at least one recovery unit (12), The system includes a control device (17) that performs recovery process control, including power application control such as applying a first potential between the working electrode and the counter electrode so that the electrochemical cell adsorbs carbon dioxide, or applying a second potential between the working electrode and the counter electrode so that the electrochemical cell desorbs the adsorbed carbon dioxide. The control device is configured to communicate with an external system (20), As surrounding information indicating the conditions around the carbon dioxide capture system, an information acquisition step (S11) is performed, in which weather information including current weather conditions and future weather conditions is acquired from the external system. The system includes a control setting step (S12 to S14, 30) for setting the control content of the recovery process control according to the weather information, The control setting step is, A carbon dioxide capture system that determines whether the current weather conditions and future weather conditions will affect carbon dioxide capture, and if it determines that there will be an impact, switches from the current mode to a proactive mode that anticipates future weather conditions and executes the capture process control in advance.

2. In the information acquisition step, the weather information is acquired as the surrounding information. The carbon dioxide capture system according to claim 1, wherein the control setting step sets the control content of the capture process control according to the weather information.

3. The carbon dioxide capture system according to claim 2, wherein in the control setting step, if the weather information indicates that the weather conditions after a predetermined time are suitable for carbon dioxide capture, the control content of the capture process control is set in advance to increase the amount of carbon dioxide captured compared to the current amount, and if the weather information indicates that the weather conditions after a predetermined time are not suitable for carbon dioxide capture, the control content of the capture process control is set in advance to suppress the energy required for carbon dioxide capture compared to the current amount.

4. The carbon dioxide recovery system according to claim 3, wherein in the control setting step, if the weather information indicates that the weather conditions after a predetermined time are suitable for carbon dioxide recovery, the control content of the recovery process control is set to increase the amount of carbon dioxide recovered compared to the current time by setting the application time of the first potential and the application time of the second potential to a longer time than the current time.

5. The carbon dioxide capture system according to claim 3, wherein in the control setting step, if the weather information indicates that the weather conditions after a predetermined time are not suitable for carbon dioxide capture, the control content of the capture process control is set to a shorter time than currently required to reduce the energy required for carbon dioxide capture than currently required.

6. In the aforementioned information acquisition step, at least one of the future weather information and warning information is acquired as the surrounding information. The carbon dioxide recovery system according to any one of claims 1 to 5, wherein in the control setting step, a stop process is set as the control content of the recovery process control according to the surrounding information.

7. The carbon dioxide recovery system according to claim 6, wherein in the control setting step, if the surrounding information satisfies the conditions for stopping the recovery process control, one of the following is set as the stop mode, depending on the processing stage of the recovery process control from carbon dioxide adsorption to recovery to the carbon dioxide recovery tank: an immediate stop mode that immediately stops the recovery process control, and a continuous stop mode that stops the recovery process control after the recovery to the carbon dioxide recovery tank has been performed.

8. The carbon dioxide recovery system according to claim 7, wherein in the control setting step, if the elapsed time from the start of carbon dioxide adsorption is less than a predetermined time, or the elapsed time from the start of carbon dioxide recovery is predetermined or longer, the immediate stop mode is set as the stop mode in the processing stage.

9. The carbon dioxide recovery system according to claim 7, wherein in the control setting step, if the elapsed time from the start of carbon dioxide adsorption is greater than or equal to a predetermined time, and the elapsed time from the start of carbon dioxide recovery is less than a predetermined time, the continuous stop mode is set as the stop mode in the processing stage.

10. The carbon dioxide recovery system according to claim 9, wherein in the control setting step, if the continuous stop mode is set, a shortening control is performed to shorten the execution time until recovery to the carbon dioxide recovery tank.

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