Carbon dioxide recovery system

1 . A carbon dioxide recovery system which recovers carbon dioxide from a mixed gas containing carbon dioxide by an electrochemical reaction, the system comprising:

a carbon dioxide recovery tank which stores recovered carbon dioxide;

at least one collector device which has an electrochemical cell and a container, the electrochemical cell having a working electrode containing an adsorbent capable of adsorbing carbon dioxide and a counter electrode paired with the working electrode, the container containing the electrochemical cell and being supplied with a mixed gas;

a sensor which detects an amount of carbon dioxide recovered from the collector device to the carbon dioxide recovery tank;

a control device which is configured to acquire a correlation value correlated with a recovery amount, which is a detection result through the sensor, and control (i) an application of a first potential between the working electrode and the counter electrode only during an adsorption time corresponding to a target adsorption amount which is an adsorption amount of carbon dioxide that the adsorbent can adsorb so that the adsorbent adsorbs carbon dioxide when executing an adsorption mode in which carbon dioxide is adsorbed, or (ii) an application of a second potential between the working electrode and the counter electrode only during a recovery time corresponding to the recovery amount when executing a desorption mode in which the carbon dioxide adsorbed in the adsorbent is desorbed; and

a storage unit which stores desorption amount change data in which a desorption amount of carbon dioxide and a desorption time for obtaining the desorption amount are associated, wherein

the control device is configured to:

acquire a desorption time, as an optimum desorption time, associated with a desorption amount equivalent to a recovery amount or a target adsorption amount in the desorption amount change data;

apply a second potential only during the optimum desorption time in a desorption mode;

perform a map creation process which creates the desorption amount change data during a map creation process execution period, and a normal operation which uses the optimal desorption time acquired from the desorption amount change data during a normal operation period, and

the map creation process execution period is performed prior to the normal operation period to optimize a time for applying the second potential according to states of the electrochemical cell.

2 . The carbon dioxide recovery system according to claim 1 , wherein the control device is configured to:

perform a recovery mode which recovers the carbon dioxide desorbed from the collector device to the carbon dioxide recovery tank by starting a driving of a pump, if the optimum desorption time elapses through the application of the second potential; and

stop the driving of the pump, if the recovery amount reaches a target recovery amount.

3 . The carbon dioxide recovery system according to claim 2 , wherein the control device is configured to:

perform the recovery mode to create the desorption amount change data;

acquire the recovery amount of carbon dioxide recovered during a provisional desorption time, which is set to achieve a target desorption amount, by driving the pump in the recovery mode; and

create the desorption amount change data, in which the desorption amount and the desorption time are associated, so as to satisfy a relationship between an increase of the desorption amount and a lapse of the desorption time, including a relationship between the provisional desorption time and the desorption amount, assuming an acquired value of the recovery amount as the desorption amount.

4 . The carbon dioxide recovery system according to claim 3 , wherein a target of the desorption amount corresponds to an amount of carbon dioxide desorbed before execution of the recovery mode.

5 . The carbon dioxide recovery system according to claim 3 , wherein the control device is configured to:

update the target adsorption amount to a smaller value every predetermined period; and

update the optimum desorption time to a shorter value as the target adsorption amount is updated.

6 . The carbon dioxide recovery system according to claim 1 , wherein the control device is configured to:

repeat the map creation process after the normal operation period.

7 . The carbon dioxide recovery system according to claim 6 , wherein the optimum desorption time corresponds to a time at which an incremental increase of the desorption amount per unit time becomes smaller than a predetermined value.