Carbon dioxide capture system

Abstract

To provide a carbon dioxide recovery system capable of increasing the concentration of CO2 collected in a utilization part.SOLUTION: A control device 160 controls a recovery machine 120, a scavenge part 130, a collection part 140 and a connection part 150. Before executing a recovery step in which CO2 is detached from an electrochemical cell 121 of the recovery machine 120 and is collected in a utilization part 141 via a collection piping 142, the control device 160 controls a first collection opening / closing part 143 to a closed state, a second collection opening / closing part 144 to a closed state, a connection opening / closing part 152 to an opened state and a scavenge opening / closing part 132 to a closed state to operate the scavenge part 130, so as to execute an exhaust step of scavenging the collection piping 142 via the connection piping 151 and the scavenge piping 131.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a carbon dioxide recovery system.

Background Art

[0002] Conventionally, a carbon dioxide recovery system has been proposed, for example, in Patent Document 1. The carbon dioxide recovery system supplies CO2 that undergoes a reduction reaction to the working electrode side of an electrolyte, and supplies a substance that undergoes an oxidation reaction to the counter electrode side of the electrolyte.

[0003] Then, the carbon dioxide recovery system adsorbs CO2 to the working electrode by controlling the applied voltage between the working electrode and the counter electrode. Further, the carbon dioxide recovery system desorbs the CO2 adsorbed on the working electrode by controlling the applied voltage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The CO2 recovery device includes an electrochemical cell including a working electrode and a counter electrode, and a housing that houses the electrochemical cell. And before desorbing CO2 from the electrochemical cell, the inside of the housing is purged. As a result, the inside of the housing becomes a vacuum state. After that, CO2 is desorbed from the electrochemical cell, and CO2 is collected in the CO2 utilization part through a pipe connected to the housing.

[0006] However, in the above collection method, although the inside of the housing can be purged, air remains in the pipe connecting the housing and the utilization part. Therefore, when collecting CO2 in the utilization part, the air in the pipe is mixed into the CO2, so that the recovery concentration of CO2 decreases.

[0007] In view of the above points, the present invention aims to provide a carbon dioxide capture system that can increase the concentration of CO2 collected in the utilization section. [Means for solving the problem]

[0008] To achieve the above objective, the carbon dioxide recovery system in the invention described in claim 1 includes a recovery unit (120), a scavenging unit (130), a collection unit (140), a connecting unit (150), and a control device (160).

[0009] The recovery device includes an electrochemical cell (121) that recovers CO2 by adsorbing CO2 from a CO2-containing gas containing CO2, and an electrochemical cell (122) that can capture CO2 by desorbing CO2, and a housing (122) that houses the electrochemical cell.

[0010] The scavenging unit includes a scavenging pipe (131) that connects the inside and outside of the housing, and a scavenging opening / closing unit (132) that opens and closes the scavenging pipe.

[0011] The collection unit comprises a utilization unit (141), a collection pipe (142), a first collection opening / closing unit (143), and a second collection opening / closing unit (144). The utilization unit collects CO2. The collection pipe connects the inside of the housing to the utilization unit. The first collection opening / closing unit is located on the housing side of the collection pipe and opens and closes the collection pipe. The second collection opening / closing unit is located on the utilization unit side of the collection pipe and opens and closes the collection pipe.

[0012] The connection section includes a connecting pipe (151) and a connecting switch (152). The connecting pipe connects the downstream portion (134) of the scavenging pipe, which is on the side opposite to the housing from the scavenging switch, to the intermediate portion (146) of the collection pipe, which is between the first collection switch and the second collection switch. The connecting switch opens and closes the connecting pipe.

[0013] The control device controls the recovery unit, scavenging unit, collection unit, and connection unit. , captureBefore performing the recovery process to collect CO2 in the utilization section via the collection piping, an exhaust process is performed to scavenge the collection piping via the connecting piping and the scavenging piping by controlling the scavenging unit to the closed state of the first collection switch, the closed state of the second collection switch, the open state of the connecting switch, and the closed state of the scavenging switch.

[0014] According to this method, the middle section of the collection piping is scavenged before the CO2 is collected in the utilization section. Therefore, gases inside the collection piping are less likely to mix with the CO2 gas during collection. Consequently, the concentration of CO2 collected in the utilization section can be increased.

[0015] The reference numerals in parentheses next to each means described in this section and in the claims indicate the correspondence with the specific means described in the embodiments described later. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows a carbon dioxide capture system according to the first embodiment. [Figure 2] This is a diagram illustrating the exhaust process. [Figure 3] This is a diagram illustrating the adsorption process. [Figure 4] This diagram shows the pressure profile inside the enclosure during each process. [Figure 5] This is a diagram illustrating the removal process. [Figure 6] This is a diagram illustrating the desorption process. [Figure 7] This is a diagram illustrating the recovery process. [Figure 8] This is a diagram illustrating the detachment process according to the second embodiment. [Figure 9] This is a diagram illustrating the removal process according to the third embodiment. [Figure 10] This figure shows a carbon dioxide capture system according to the fourth embodiment. [Modes for carrying out the invention]

[0017] Hereinafter, embodiments of the present invention will be described based on the drawings. In the following embodiments, parts that are identical or equivalent to each other are denoted by the same reference numerals in the drawings.

[0018] (First Embodiment) The carbon dioxide recovery system according to this embodiment separates CO2 from a CO2-containing gas containing CO2 by an electrochemical reaction. As shown in FIG. 1, the carbon dioxide recovery system 100 includes a duct section 110, a recovery unit 120, a scavenging section 130, a collection section 140, a connection section 150, a control device 160, a power unit 170, and a pressure sensor 180.

[0019] The duct section 110 is a device for flowing a CO2-containing gas into the recovery unit 120. The CO2-containing gas is, for example, the atmosphere containing CO2. The duct section 110 has an introduction pipe 111, a first duct opening / closing section 112, a second duct opening / closing section 113, and a duct pump 114.

[0020] The introduction pipe 111 is a pipe for flowing the atmosphere into the recovery unit 120. The first duct opening / closing section 112 is disposed upstream of the recovery unit 120 in the introduction pipe 111. The first duct opening / closing section 112 opens and closes the upstream of the introduction pipe 111 according to a command from the control device 160. The second duct opening / closing section 113 is disposed downstream of the recovery unit 120 in the introduction pipe 111. The second duct opening / closing section 113 opens and closes the downstream of the introduction pipe 111 according to a command from the control device 160. The first duct opening / closing section 112 and the second duct opening / closing section 113 are, for example, valves that open or block the passage of the introduction pipe 111.

[0021] The duct pump 114 is disposed downstream of the second duct opening / closing section 113 in the introduction pipe 111. The duct pump 114 allows the atmosphere to pass through the recovery unit 120 by generating a flow of the atmosphere in the introduction pipe 111. Note that a blower fan may be used instead of the duct pump 114.

[0022] The recovery unit 120 is a device that separates and recovers CO2 from the atmosphere. The recovery unit 120 discharges CO2 removal gas after CO2 has been recovered from the atmosphere, or the CO2 recovered from the atmosphere. The recovery unit 120 has an electrochemical cell 121 and a housing 122.

[0023] The electrochemical cell 121 is a device that recovers CO2 from the atmosphere by adsorbing it, while also capturing CO2 by desorbing it. The electrochemical cell 121 performs CO2 adsorption and desorption through electrochemical reactions, enabling the separation and recovery of CO2 from the atmosphere.

[0024] The electrochemical cell 121 is an electric field cell stack in which multiple cell sections, each having a working electrode, a counter electrode, an insulating layer, and an ion-conducting member, are stacked. The working electrode, counter electrode, and insulating layer are each configured in a plate shape. The working electrode is the negative electrode. The counter electrode is the positive electrode.

[0025] The working electrode contains a CO2 adsorbent. The CO2 adsorbent is an electroactive species that possesses redox activity and is capable of reversibly undergoing oxidation-reduction reactions. The CO2 adsorbent can bind to and adsorb CO2 in the reduced state and release CO2 in the oxidized state. The CO2 adsorbent has functional groups that bind to CO2. These functional groups that bind to CO2 become CO2 adsorption sites through electron transfer.

[0026] The working electrode comprises a working electrode substrate, a working electrode conductive additive, and a working electrode binder, in addition to the CO2 adsorbent. The working electrode substrate is a porous conductive material that allows CO2 to pass through. The working electrode conductive additive is a conductive substance that forms a conductive path to the CO2 adsorbent. The working electrode binder is a retaining material for holding the CO2 adsorbent and the working electrode conductive additive to the working electrode substrate. The CO2 adsorbent, the working electrode conductive additive, and the working electrode binder are provided inside the porous working electrode substrate.

[0027] The counter electrode has the same configuration as the working electrode. The counter electrode contains a counter-electrode active material. The counter-electrode active material is an auxiliary electroactive species that has an opposite oxidation-reduction state to the CO2 adsorbent and facilitates the transfer of electrons between it and the CO2 adsorbent. As the counter-electrode active material, for example, a metal complex that enables the transfer of electrons by changing the valence of a metal ion can be used.

[0028] The counter electrode comprises, in addition to the counter electrode-side active material, a counter electrode-side substrate, a counter electrode-side conductive additive, and a counter electrode-side binder. The counter electrode-side substrate, counter electrode-side conductive additive, and counter electrode-side binder may be made of the same materials as those used in the working electrode, or they may be made of different materials.

[0029] The insulating layer is placed between the working electrode and the counter electrode. The insulating layer separates the working electrode and the counter electrode. The insulating layer prevents physical contact between the working electrode and the counter electrode. In addition, the insulating layer suppresses electrical short circuits between the working electrode and the counter electrode. A separator or a gaseous layer such as air can be used as the insulating layer.

[0030] The ion-conducting member is placed between the working electrode and the counter electrode. Specifically, the ion-conducting member is placed between the working electrode-side substrate and the counter electrode-side substrate via an insulating layer.

[0031] The ion-conducting member is in contact with the CO2 adsorbent inside the working electrode substrate. The ion-conducting member has ionic conductivity. This promotes conductivity to the CO2 adsorbent. The ions contained in the ion-conducting member do not directly react with the functional groups that bind to CO2 contained in the CO2 adsorbent. The ion-conducting member may be made of the same material as the working electrode binder, or a different material may be used.

[0032] The housing 122 is a container for housing the electrochemical cell 121. The housing 122 can be sealed by stopping the flow of gas through the opening / closing section 112 for the first duct, the opening / closing section 113 for the second duct, the scavenging section 130, and the collection section 140. The housing 122 may also be configured as part of the introduction piping 111.

[0033] The scavenging unit 130 is a device for scavenging the inside of the housing 122 of the recovery unit 120 when the electrochemical cell 121 has adsorbed CO2 and the housing 122 is sealed. In other words, the scavenging unit 130 creates a vacuum inside the housing 122.

[0034] Here, the state in which the housing 122 is sealed means that at least the duct section 110 prevents air from being introduced into the housing 122. In order for the scavenging section 130 to scavenge the inside of the housing 122, it is necessary that the sealed housing 122 and the scavenging section 130 are connected. Similarly, in order for CO2 to be collected from the recovery unit 120 to the collection unit 140, it is necessary that the sealed housing 122 and the collection unit 140 are connected.

[0035] The scavenging unit 130 includes a scavenging pipe 131, a scavenging on / off unit 132, and a scavenging pump 133.

[0036] The scavenging pipe 131 is a pipe that connects the inside and outside of the housing 122. One end of the scavenging pipe 131 is connected to the housing 122. The other end of the scavenging pipe 131 is open to the atmosphere. In this way, the inside of the housing is connected to the outside of the housing 122 via the scavenging pipe 131. The scavenging switch 132 opens and closes the scavenging pipe 131 according to a command from the control device 160. The scavenging switch 132 is, for example, a valve that opens or closes the passage of the scavenging pipe 131.

[0037] The scavenging pump 133 is positioned downstream of the scavenging opening / closing section 132 in the scavenging piping 131. The scavenging pump 133 scavenges the inside of the housing 122 of the recovery unit 120 by generating a gas flow in the scavenging piping 131. The scavenging pump 133 is either a dry-type pump or an oil-type pump.

[0038] The collection unit 140 is a device for collecting CO2 recovered by the recovery unit 120. The collection unit 140 includes a utilization unit 141, a collection pipe 142, a first collection opening / closing unit 143, a second collection opening / closing unit 144, and a collection pump 145.

[0039] The utilization unit 141 is a device for utilizing the CO2 recovered by the recovery unit 120. The utilization unit 141 collects CO2 from the recovery unit 120 via the collection piping 142. The utilization unit 141 is, for example, a tank for storing CO2. However, the utilization unit 141 may be a factory or equipment that utilizes CO2 instead of a tank.

[0040] The collection pipe 142 is a pipe that connects the inside of the housing 122 to the utilization section 141. One end of the collection pipe 142 is connected to one end of the scavenging pipe 131. Therefore, one end of the collection pipe 142 is common to one end of the scavenging pipe 131. Of course, one end of the collection pipe 142 and one end of the scavenging pipe 131 may each be independently connected to the housing 122. The other end of the collection pipe 142 is connected to the utilization section 141. 。

[0041] The first collection opening / closing unit 143 is located on the housing 122 side of the collection piping 142. The first collection opening / closing unit 143 opens and closes the housing 122 side of the collection piping 142 according to a command from the control device 160. The second collection opening / closing unit 144 is located on the utilization side 141 of the collection piping 142. The second collection opening / closing unit 144 opens and closes the utilization side 141 of the collection piping 142 according to a command from the control device 160. The second collection opening / closing section 144 is, for example, a valve that opens or closes the passage of the collection piping 142.

[0042] The collection pump 145 is a dry-type pump for drawing the CO2 collected by the recovery unit 120 into the utilization unit 141. The collection pump 145 is located in the intermediate section 146 of the collection piping 142, between the first collection opening / closing section 143 and the second collection opening / closing section 144. Alternatively, the collection pump 145 may be located between the second collection opening / closing section 144 and the utilization unit 141 of the collection piping 142.

[0043] The connecting section 150 is a device that connects the scavenging section 130 and the collection section 140. The connecting section 150 has a connecting pipe 151 and a connecting opening / closing section 152. One end of the connecting pipe 151 is connected to the intermediate section 146 of the scavenging pipe 131.

[0044] Specifically, the connection point 147 between one end of the connecting pipe 151 and the connecting pipe 151 is located between the collection pump 145 and the utilization section 141 in the intermediate section 146 of the collection pipe 142. The other end of the connecting pipe 151 is connected to the downstream section 134 of the scavenging pipe 131, on the side opposite to the housing 122 from the scavenging opening / closing section 132.

[0045] The connecting section 147 may also be located between the first collection opening / closing section 143 and the collection pump 145 in the intermediate section 146 of the collection piping 142. In this case, the distance between the collection pump 145 and the utilization section 141 in the intermediate section 146 can be shortened.

[0046] The connecting switch 152 opens and closes the connecting pipe 151 according to a command from the control device 160. The connecting switch 152 is, for example, a valve that opens or closes the passage of the connecting pipe 151.

[0047] The control device 160 consists of a well-known microcomputer including a CPU, ROM, and RAM, and its peripheral circuits. The control device 160 performs various calculations and processes according to the control program stored in the ROM.

[0048] Furthermore, the control device 160 controls the first duct opening / closing section 112, the second duct opening / closing section 113, and the duct pump 114 of the duct section 110. The control device 160 controls the voltage applied to the electrochemical cell 121 of the recovery unit 120, and the scavenging opening / closing section 132 and the scavenging pump 133 of the scavenging unit 130. The control device 160 controls the utilization section 141, the first collection opening / closing section 143, the second collection opening / closing section 144, and the collection pump 145 of the collection unit 140, and the connection opening / closing section 152 of the connection unit 150.

[0049] The power unit 170 is the power supply device for the carbon dioxide capture system 100. The power unit 170 supplies power to the duct section 110, the capture unit 120, the scavenging section 130, the collection section 140, the connection section 150, and the pressure sensor 180 according to the commands of the control device 160. The power unit 170 changes the potential difference between the working electrode and the counter electrode by applying a predetermined voltage to the electrochemical cell 121 of the capture unit 120 according to the commands of the control device 160.

[0050] The pressure sensor 180 is a device for detecting the internal pressure of the housing 122 of the recovery unit 120. The pressure sensor 180 is installed, for example, at one end of the scavenging pipe 131. The pressure sensor 180 outputs a detection signal to the control device 160. The above is the overall configuration of the carbon dioxide recovery system 100 according to this embodiment.

[0051] Next, the operation of the carbon dioxide capture system 100 will be described. The control device 160 performs an initial step, an adsorption step, a removal step, a desorption step, and a recovery step in order to capture CO2 in the utilization unit 141.

[0052] First, the control device 160 performs an initial process. The initial process is an exhaust process that discharges the gas remaining in the collection piping 142 of the collection unit 140. In this embodiment, the initial process is performed once after the carbon dioxide recovery system 100 is started up and before the adsorption process is performed.

[0053] As shown in Figure 2, the duct section 110, the scavenging section 130, and the collection section 140 are operated. Specifically, the control device 160 controls the first duct opening / closing section 112, the second duct opening / closing section 113, the scavenging opening / closing section 132, the first collection opening / closing section 143, and the second collection opening / closing section 144 to the closed state. The control device 160 also controls the duct pump 114 to the OFF state.

[0054] Furthermore, the control device 160 controls the connection opening / closing section 152 to the open state, and controls the scavenging pump 133 and the collection pump 145 to the ON state. As a result, the control device 160 scavenges the gas in the intermediate section 146 of the collection piping 142 via the connection piping 151 and the downstream section 134 of the scavenging piping 131. The control device 160 also scavenges the inside of the dry-type collection pump 145.

[0055] After the initial process, the control device 160 performs an adsorption process to adsorb CO2 onto the electrochemical cell 121. As shown in Figure 3, the control device 160 controls the first collection switch 143, the second collection switch 144, the connection switch 152, and the scavenging switch 132 to the closed state. The control device 160 also controls the scavenging pump 133 and the collection pump 145 to the OFF state.

[0056] Furthermore, the control device 160 controls the first duct opening / closing section 112 and the second duct opening / closing section 113 to the open state, and controls the duct pump 114 to the ON state. As a result, atmospheric air is supplied to the electrochemical cell 121 of the recovery unit 120. Therefore, as shown in Figure 4, the pressure inside the housing 122 becomes atmospheric pressure P0.

[0057] The control device 160 applies an adsorption potential between the working electrode and the counter electrode of the electrochemical cell 121 by controlling the power unit 170. This allows for simultaneous electron donation by the counter electrode's active material and electron withdrawal by the CO2 adsorbent at the working electrode.

[0058] When an adsorption potential is applied between the working electrode and the counter electrode, the counter-side active material on the counter electrode releases electrons and enters an oxidized state, supplying electrons from the counter electrode to the working electrode. The CO2 adsorbent on the working electrode accepts electrons and enters a reduced state.

[0059] When the CO2 adsorbent is in a reduced state, its ability to bind to CO2 increases, and it binds to and adsorbs CO2 contained in the atmosphere. In this way, in the electrochemical cell 121, when an adsorption potential is applied between the working electrode and the counter electrode, electrons are supplied from the counter electrode to the working electrode, and the CO2 adsorbent binds to CO2 as electrons are supplied. Therefore, the recovery unit 120 can recover CO2 from the atmosphere.

[0060] After atmospheric CO2 is recovered in the recovery unit 120, CO2-free air is discharged from the recovery unit 120. The control device 160 terminates the adsorption process based, for example, on the detection results of a CO2 sensor (not shown) located downstream of the introduction piping 111.

[0061] After the adsorption process, the control device 160 performs a removal process to scavenge the inside of the housing 122 of the recovery unit 120. As shown in Figure 5, the control device 160 controls the duct pump 114 and the collection pump 145 to the OFF state while CO2 is adsorbed on the electrochemical cell 121, that is, while an adsorption potential is applied to the electrochemical cell 121.

[0062] Furthermore, the control device 160 controls the first duct opening / closing section 112, the second duct opening / closing section 113, the first collection opening / closing section 143, the second collection opening / closing section 144, and the connection opening / closing section 152 to the closed state. The control device 160 also controls the scavenging opening / closing section 132 to the open state and controls the scavenging pump 133 to the ON state.

[0063] This allows the inside of the housing 122 of the recovery unit 120 to be scavenged via the scavenging pipe 131. Consequently, as shown in Figure 4, the pressure inside the housing 122 drops to the removal target pressure P1. The control device 160 terminates the removal process when the pressure inside the housing 122 reaches the removal target pressure P1.

[0064] After the removal process, the control device 160 performs a desorption process to desorb the CO2 adsorbed on the electrochemical cell 121. As shown in Figure 6, with CO2 adsorbed on the electrochemical cell 121, the control device 160 controls the duct pump 114, the collection pump 145, and the scavenging pump 133 to the OFF state.

[0065] Furthermore, the control device 160 controls all of the following to be in a closed state: the first duct opening / closing section 112, the second duct opening / closing section 113, the first collection opening / closing section 143, the second collection opening / closing section 144, the connection opening / closing section 152, and the scavenging opening / closing section 132.

[0066] The control device 160 then controls the power unit 170 to apply a desorption potential between the working electrode and the counter electrode of the electrochemical cell 121. This allows for the simultaneous donation of electrons by the CO2 adsorbent at the working electrode and the withdrawal of electrons by the counter-side active material at the counter electrode.

[0067] The CO2 adsorbent at the working electrode releases electrons and enters an oxidized state. The CO2 adsorbent's binding force to CO2 decreases, causing it to desorb and release. The counter electrode's counter-electrode active material accepts electrons and enters a reduced state.

[0068] In this way, CO2 is desorbed from the electrochemical cell 121. The CO2 is released into the housing 122. Therefore, as shown in Figure 4, at the end of the desorption process, the pressure inside the housing 122 rises to the desorption target pressure P2.

[0069] After the desorption process, the control device 160 performs a recovery process to collect the CO2 desorbed from the electrochemical cell 121. As shown in Figure 7, with CO2 desorbed from the electrochemical cell 121, the control device 160 controls the first duct opening / closing section 112, the second duct opening / closing section 113, the connecting opening / closing section 152, and the scavenging opening / closing section 132 to the closed state. The control device 160 also controls the duct pump 114 and the scavenging pump 133 to the OFF state.

[0070] The control device 160 then controls the first collection opening / closing section 143 and the second collection opening / closing section 144 to the open state, and controls the collection pump 145 to the ON state. As a result, the CO2 released from the CO2 adsorbent is discharged from the recovery unit 120 and collected in the utilization unit 141 via the collection piping 142.

[0071] While CO2 is being collected in the utilization unit 141, the collection pump 145 is operating. Therefore, as shown in Figure 4, the pressure inside the housing 122 drops to the recovery target pressure P3. After the recovery process, the system moves to the adsorption process, and the pressure inside the housing 122 returns to atmospheric pressure P0.

[0072] The above-described adsorption, removal, desorption, and recovery processes constitute one cycle. The control device 160 controls the repetition of the cycle. When the control device 160 performs the initial process, i.e., the exhaust process, once, at least the intermediate section 146 of the collection piping 142 becomes a vacuum. Furthermore, after the first recovery process in one of the multiple cycles, at least the intermediate section 146 of the collection piping 142 is filled with CO2 gas. Therefore, the exhaust process does not need to be performed in the second and subsequent cycles. Of course, when continuous operation of the cycle ends and the inside of the intermediate section 146 of the collection piping 142 returns to the atmosphere, the initial process should be performed when continuous operation of the cycle is restarted.

[0073] As described above, in this embodiment, before performing the recovery process in which CO2 desorbed from the electrochemical cell 121 is collected in the utilization section 141 via the collection pipe 142, an exhaust process is performed to scavenge the collection pipe 142. As a result, at least the intermediate section 146 of the collection pipe 142 is scavenged, making it less likely for gas inside the collection pipe 142 to mix with the CO2 gas during CO2 collection. Therefore, the concentration of CO2 collected in the utilization section 141 can be increased.

[0074] In particular, when the collection pipe 142 is long or wide, the amount of gas remaining in the collection pipe 142 increases. Even in such cases, the CO2 collection concentration can be increased. In order to scavenge the gas in the collection pipe 142 as much as possible, it is preferable that the first collection opening / closing section 143 be located as close as possible to the housing 122, and the second collection opening / closing section 144 be located as close as possible to the utilization section 141. Furthermore, it is preferable that the connecting opening / closing section 152 be located as close as possible to the connecting section 147.

[0075] Furthermore, when operating the cycle continuously, it is sufficient to perform the exhaust process only once before the adsorption process, so it is not necessary to perform the exhaust process every time during continuous cycle operation. Of course, it is also possible to perform the exhaust process before each cycle, or every few cycles.

[0076] Furthermore, since a dry-type pump is used as the collection pump 145, the inside of the collection pump 145 can also be exhausted during the exhaust process. Therefore, a higher concentration of CO2 can be collected.

[0077] (Second Embodiment) This embodiment will mainly describe the differences from the first embodiment. In this embodiment, the control device 160 performs an exhaust process after the removal process. This provides the same effects as in the first embodiment.

[0078] Specifically, one cycle consists of an adsorption process, a removal process, an exhaust process, a desorption process, and a recovery process. That is, the control device 160 performs an exhaust process after the removal process, and a desorption process after the exhaust process.

[0079] Alternatively, the control device 160 performs the exhaust process simultaneously with the desorption process. That is, the adsorption process, removal process, desorption process (exhaust process), and recovery process constitute one cycle. In this case, as shown in Figure 8, the control device 160 controls the connection switch 152 to the open state and controls the scavenging pump 133 and the collection pump 145 to the ON state during the desorption process. Since there is no need to perform the exhaust process separately, the time required for the exhaust process is eliminated.

[0080] Furthermore, during continuous operation of the cycle, it is not necessary to perform the exhaust process after the removal process every time. The exhaust process may be performed after the removal process every few cycles.

[0081] (Third embodiment) This embodiment will mainly describe the differences from the first and second embodiments. In this embodiment, the control device 160 performs the removal process and the exhaust process simultaneously during the removal process. In other words, the adsorption process, removal process (exhaust process), desorption process, and recovery process constitute one cycle.

[0082] Specifically, as shown in Figure 9, the control device 160 controls the state of each opening / closing unit 112, 113, 132, 143, 144, 152 and each pump 114, 133, 145 during the removal process, changing the connecting opening / closing unit 152 from closed to open. The control device 160 also controls the collection pump 145 from OFF to ON.

[0083] In other words, the control device 160 controls the scavenging opening / closing unit 132 from closed to open in the state of each opening / closing unit 112, 113, 132, 143, 144, 152 and each pump 114, 133, 145 during the exhaust process.

[0084] In this process, the first collection opening / closing section 143 is in the closed state during the exhaust and removal processes. However, when the exhaust and removal processes are performed simultaneously, the first collection opening / closing section 143 may be in either the closed or open state.

[0085] This provides the same effects as in the first embodiment. Furthermore, since the exhaust process can be performed during the removal process, the time required for the exhaust process is eliminated.

[0086] (Fourth Embodiment) This embodiment will mainly describe the differences from the embodiments described above. In this embodiment, an oil-type pump is used as the collection pump 145 of the collection unit 140.

[0087] In this case, as shown in Figure 10, the collection unit 140 has a third collection opening / closing unit 148. The third collection opening / closing unit 148 is, for example, a valve that opens or closes the passage of the collection piping 142. The third collection opening / closing unit 148 is located upstream of the collection pump 145. The first collection opening / closing unit 143 is located downstream of the collection pump 145.

[0088] Furthermore, during the exhaust process and the removal process, the control device 160 controls the third collection opening / closing section 148 and the first collection opening / closing section 143 to a closed state. As a result, the oil in the oil-type collection pump 145 is not scavenged. Also, during the recovery process, the control device 160 controls the third collection opening / closing section 148 and the first collection opening / closing section 143 to an open state, and controls the collection pump 145 to an ON state.

[0089] As described above, when using the oil-type collection pump 145, a third collection opening / closing section 148 is provided. Therefore, oil leakage from the oil-type collection pump 145 can be prevented during the exhaust process and the removal process.

[0090] (Other embodiments) The configurations of the carbon dioxide capture system 100 shown in each of the above embodiments are examples, and the present invention can be realized with other configurations without being limited to those shown above. For example, the CO2-containing gas is not limited to the atmosphere, but can be any gas that contains CO2.

[0091] Furthermore, the carbon dioxide capture system 100 does not necessarily have a duct section 110. In this case, the housing 122 of the capture unit 120 only needs to have an openable and closable door for taking in air and sealing it. When the carbon dioxide capture system 100 is installed outdoors, natural wind passes through the inside of the housing 122. [Explanation of symbols]

[0092] 120 Recovery unit, 121 Electrochemical cell, 122 Housing, 130 Scavenging unit, 131 Scavenging piping, 132 Scavenging switch, 134 Downstream unit, 140 Collection unit, 141 Utilization unit, 142 Collection piping, 143 First collection switch, 144 Second collection switch, 145 Collection pump, 146 Intermediate unit, 147 Connecting unit, 150 Connection unit, 151 Connection piping, 152 Connection switch, 160 Control device

Claims

1. CO ２ Contains CO ２ From the contained gas, the CO ２ By adsorbing the CO ２ While recovering the CO ２ By removing the CO ２ A recovery device (120) having an electrochemical cell (121) capable of collecting and a housing (122) that houses the electrochemical cell, A scavenging unit (130) having a scavenging pipe (131) connecting the inside and outside of the housing, and a scavenging opening / closing unit (132) for opening and closing the scavenging pipe, The aforementioned CO ２ A collection unit (140) having a utilization unit (141) for collecting, a collection pipe (142) connecting the inside of the housing and the utilization unit, a first collection opening / closing unit (143) provided on the housing side of the collection pipe and opening and closing the collection pipe, and a second collection opening / closing unit (144) provided on the utilization unit side of the collection pipe and opening and closing the collection pipe, A connecting pipe (151) that connects the downstream portion (134) of the scavenging pipe on the side opposite to the housing from the scavenging opening / closing section, and the intermediate portion (146) of the collection pipe from the first collection opening / closing section to the second collection opening / closing section, and a connecting opening / closing section (152) that opens and closes the connecting pipe, is provided for the connecting section (150), A control device (160) that controls the recovery device, the scavenging unit, the collection unit, and the connection unit, Includes, The control device, via the collection piping, uses the CO2 in the utilization section. ２ A carbon dioxide recovery system that, before performing a recovery process to collect carbon dioxide, operates the scavenging unit by controlling the first collection opening / closing unit to be in a closed state, the second collection opening / closing unit to be in a closed state, the connecting opening / closing unit to be in an open state, and the scavenging opening / closing unit to be in a closed state, thereby performing an exhaust process to scavenge the collection pipe via the connecting pipe and the scavenging pipe.

2. The control device performs the exhaust process before the adsorption process of adsorbing the CO ２ to the electrochemical cell. The carbon dioxide recovery system according to claim 1.

3. The control device provides the electrochemical cell with the CO ２ The carbon dioxide recovery system according to claim 1, wherein, after a removal step of sweeping the inside of the housing through the sweeping pipe while the carbon dioxide has been adsorbed, the exhaust step is performed.

4. The carbon dioxide recovery system according to claim 1, wherein the control device, when performing the exhaust process, controls the scavenging opening / closing unit from closed to open and operates the scavenging unit while the electrochemical cell has adsorbed the CO2, thereby simultaneously performing a removal process to scavenge the inside of the housing and the exhaust process.

5. The collection unit is provided between the first collection opening / closing unit and the connecting unit (147) of the collection piping to which the connecting pipe is connected, and the CO ２ It has a dry-type collection pump (145) for drawing the material into the utilization section, The carbon dioxide recovery system according to any one of claims 1 to 4, wherein the control device, in the exhaust process, scavenges the intermediate portion of the collection piping and scavenges the inside of the collection pump.

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