Carbon dioxide electrolytic device and method of controlling carbon dioxide electrolytic device
A carbon dioxide electrolytic device includes: a carbon dioxide electrolysis cell having a cathode and an anode flow path, a cathode, an anode, and a first diaphragm; a first current regulator to supply a first current; a first gas/liquid separator to separate a first fluid from the anode flow path into a first liquid and gas; an electrodialysis cell having, first and second electrodes, first to fourth rooms, and second to fourth diaphragms; a second current regulator to supply a second current; at least one detector out of a first detector to detect a flow rate of the first gas or a concentration of carbon dioxide in the first gas, and a second detector to detect a pH or a concentration of at least one ion in the first fluid; and a first controller to regulate a second current, in accordance with at least one detection signal.
1 . A carbon dioxide electrolytic device, comprising:
a carbon dioxide electrolysis cell having
a cathode flow path through which carbon dioxide flows,
an anode flow path through which an electrolytic solution containing water flows,
a cathode on or in the cathode flow path, the cathode being configured to reduce the carbon dioxide to produce a carbon compound,
an anode on or in the anode flow path, the anode being configured to oxidize the water to produce oxygen, and
a first diaphragm between the anode flow path and the cathode flow path;
a first current regulator configured to supply a first current to the carbon dioxide electrolysis cell;
a first gas/liquid separator configured to separate a first fluid to be discharged from the anode flow path into a first liquid and a first gas;
an electrodialysis cell having
a first room, a first electrode in the first room,
a second room, a second electrode in the second room,
a third room between the first room and the second room, the third room being configured to store the first liquid to be supplied from the first gas/liquid separator,
a fourth room between the third room and the second room,
a second diaphragm between the first room and the third room,
a third diaphragm between the second room and the fourth room, and
a fourth diaphragm between the third room and the fourth room;
a second current regulator configured to supply a second current to the electrodialysis cell;
at least one detector selected from the group consisting of a first detector and a second detector, the first detector being configured to detect a flow rate of the first gas or a concentration of carbon dioxide contained in the first gas, and the second detector being configured to detect a pH of the first fluid or a concentration of at least one ion contained in the first fluid; and
a first controller configured to control the second current regulator to regulate a value of the second current, in accordance with at least one detection signal from the at least one detector.
2 . The device according to claim 1 , further comprising:
a third detector configured to detect a concentration of carbon dioxide contained in the first fluid; and
a second controller configured to control the first current regulator to regulate a value of the first current, in accordance with a detection signal from the third detector.
3 . The device according to claim 2 , further comprising
a flow rate regulator configured to regulate a flow rate of a second fluid to be supplied to the cathode flow path, the second fluid containing carbon dioxide, wherein
the second controller is configured to control the flow rate regulator to regulate the flow rate of the second fluid, in accordance with the detection signal from the third detector.
4 . The device according to claim 1 , further comprising
a pump configured to supply a third fluid to be discharged from the fourth room to the anode flow path, wherein
the first controller is configured to control the pump to regulate a flow rate of the third fluid to be supplied to the anode flow path, in accordance with the at least one detection signal from the at least one detector.
5 . The device according to claim 1 , further comprising
a second gas/liquid separator configured to separate a fourth fluid to be discharged from the third room into a second liquid and a second gas, the second liquid containing the electrolytic solution, and the second gas containing the carbon dioxide, wherein:
the second liquid is supplied to the fourth room; and
the second gas is supplied to the cathode flow path.
6 . The device according to claim 1 , wherein
the electrolytic solution contains at least one ion selected from the group consisting of a hydroxide ion, a carbonate ion, and a hydrogen carbonate ion.
7 . The device according to claim 1 , further comprising:
a fourth detector is configured to detect a concentration of at least one component contained in the first liquid; and
a purge valve configured to replenish the electrolytic solution to the first liquid or discharge a part of the first liquid, wherein
the first controller is configured to control the purge valve to replenish the electrolytic solution or discharge a part of the first liquid so that the concentration of the at least one component contained in the first liquid is a predetermined value or less, in accordance with a detection signal from the fourth detector.
8 . A method of controlling a carbon dioxide electrolytic device,
the device comprising:
a carbon dioxide electrolysis cell having
a cathode flow path through which carbon dioxide flows,
an anode flow path through which an electrolytic solution containing water flows,
a cathode on or in the cathode flow path, the cathode being configured to reduce the carbon dioxide to produce a carbon compound,
an anode on or in the anode flow path, the anode being configured to oxidize the water to produce oxygen, and
a first diaphragm between the anode flow path and the cathode flow path;
a first gas/liquid separator configured to separate a first fluid to be discharged from the anode flow path into a first liquid and a first gas; and
an electrodialysis cell having
a first room, a first electrode in the first room,
a second room, a second electrode in the second room,
a third room between the first room and the second room, the third room being configured to store the first liquid to be supplied from the first gas/liquid separator,
a fourth room between the third room and the second room,
a second diaphragm between the first room and the third room,
a third diaphragm between the second room and the fourth room, and
a fourth diaphragm between the third room and the fourth room,
the method comprising:
separating the first fluid discharged from the anode flow path into the first liquid and a first gas, and detecting at least one selected from the group consisting of a flow rate of the first gas or a concentration of carbon dioxide contained in the first gas, and a pH of the first fluid or a concentration of at least one ion contained in the first fluid; and
regulating a value of a current to be supplied to the electrodialysis cell, in accordance with a result of the at least one detection.