Electrolysis device, electrolysis system, and method of operating electrolysis device

Abstract

An electrolysis device includes: a first electrolysis cell to reduce a reducible material and oxidize an oxidizable material; a second electrolysis cell to reduce the reducible material and oxidize the oxidizable material; a first supply source to supply a first fluid containing gas of the reducible material to the cells; a second supply source to supply a second fluid containing liquid of the oxidizable material to the cells; and at least one power supply to supply a first and a second power supply current to the first and the second electrolysis cell respectively. The at least one power supply can set values of the first and second power supply currents so that a current density of current flowing through the second electrolysis cell when reducing the reducible material is higher than a current density of current flowing through the first electrolysis cell when reducing the reducible material.

What is claimed is: 
     
         1 . An electrolysis device comprising:
 a first electrolysis cell configured to reduce a reducible material and to oxidize an oxidizable material;   a second electrolysis cell configured to reduce the reducible material and to oxidize the oxidizable material;   a first supply source configured to supply a first fluid to the first electrolysis cell and the second electrolysis cell, the first fluid containing a gas of the reducible material;   a second supply source configured to supply a second fluid to the first electrolysis cell and the second electrolysis cell, the second fluid containing a liquid of the oxidizable material; and   at least one power supply configured to supply a first power supply current to the first electrolysis cell and to supply a second power supply current to the second electrolysis cell, wherein   the at least one power supply is configured to set a value of the first power supply current and a value of the second power supply current so that a current density of current flowing through the second electrolysis cell when reducing the reducible material is higher than a current density of current flowing through the first electrolysis cell when reducing the reducible material.   
     
     
         2 . The device according to  claim 1 , wherein:
 the first electrolysis cell has:
 a first membrane electrode assembly having a first cathode, a first anode, and a first diaphragm between the first cathode and the first anode; 
 a first cathode flow path plate having a first cathode flow path facing on the first cathode; and 
 a first anode flow path plate having a first anode flow path facing on the first anode; 
   the second electrolysis cell has:
 a second membrane electrode assembly having a second cathode, a second anode, and a second diaphragm between the second cathode and the second anode; 
 a second cathode flow path plate having a second cathode flow path facing on the second cathode; and 
 a second anode flow path plate having a second anode flow path facing on the second anode; and 
   the device further comprises:   a first cathode current collector electrically connected to the first cathode and the at least one power supply;   a first anode current collector electrically connected to the first anode and the at least one power supply;   a second cathode current collector electrically connected to the second cathode and the at least one power supply; and   a second anode current collector electrically connected to the second anode and the at least one power supply.   
     
     
         3 . The device according to  claim 2 , wherein
 the second cathode flow path is connected in series to the first cathode flow path.   
     
     
         4 . The device according to  claim 2 , wherein
 the second cathode flow path is connected in parallel to the first cathode flow path.   
     
     
         5 . The device according to  claim 2 , wherein:
 the at least one power supply includes a power supply configured to supply the first power supply current to the first electrolysis cell via the first cathode current collector and the first anode current collector and supply the second power supply current to the second electrolysis cell via the second cathode current collector and the second anode current collector; and   the first cathode current collector, the first anode current collector, the second cathode current collector, and the second anode current collector are electrically connected to the power supply.   
     
     
         6 . The device according to  claim 2 , wherein
 the at least one power supply includes:   a first power supply configured to supply the first power supply current to the first electrolysis cell via the first cathode current collector and the first anode current collector; and   a second power supply configured to supply the second power supply current to the second electrolysis cell via the second cathode current collector and the second anode current collector.   
     
     
         7 . The device according to  claim 1 , wherein:
 the first fluid contains a first gas and a second gas;   the first gas is gas of carbon dioxide;   the second gas is gas of a substance different from the carbon dioxide;   the first electrolysis cell and the second electrolysis cell reduce the carbon dioxide and reduce the substance; and   a reduction potential of the carbon dioxide is higher than a reduction potential of the substance.   
     
     
         8 . The device according to  claim 7 , wherein
 the substance is oxygen.   
     
     
         9 . The device according to  claim 7 , wherein
 the substance is nitrogen.   
     
     
         10 . The device according to  claim 7 , wherein
 a concentration of the second gas of the first fluid is 1 ppm or higher and 100000 ppm or lower.   
     
     
         11 . The device according to  claim 2 , further comprising
 a third electrolysis cell between the second cathode current collector and the second anode current collector, wherein   the third electrolysis cell having
 a third cathode; 
 a third anode; 
 a third diaphragm between the third cathode and the third anode; 
 a third cathode flow path plate having a third cathode flow path facing on the third cathode; and 
 a fourth anode flow path plate having a third anode flow path facing on the third anode; and 
   the third cathode is electrically connected to the second anode, or the third anode is electrically connected to the second cathode.   
     
     
         12 . The device according to  claim 2 , further comprising:
 a first pipe configured to connect the first electrolysis cell and the second electrolysis cell, and supply the first fluid from the first cathode flow path to the second cathode flow path; and   a second pipe configured to connect the first electrolysis cell and the second electrolysis cell, and supply the second fluid from the first anode flow path to the second anode flow path.   
     
     
         13 . The device according to  claim 2 , wherein
 the first cathode has a first catalyst;   the second cathode has a second catalyst; and   the first catalyst is different from the second catalyst.   
     
     
         14 . The device according to  claim 2 , wherein:
 the first fluid contains gas of carbon dioxide;   the first electrolysis cell is configured to reduce carbon dioxide by the first cathode to produce a carbon compound; and   the second electrolysis cell is configured to reduce the carbon dioxide by the second cathode to produce the carbon compound.   
     
     
         15 . The device according to  claim 2 , wherein
 the first fluid contains a gas of nitrogen;   the first electrolysis cell is configured to reduce nitrogen by the first cathode to produce ammonia; and   the second electrolysis cell is configured to reduce the nitrogen by the second cathode to produce the ammonia.   
     
     
         16 . The device according to  claim 2 , wherein
 the first electrolysis cell comprises:
 a first membrane electrode assembly having the first cathode, the first anode, and the first diaphragm; 
 a first supporting plate surrounding the first membrane electrode assembly and having a first opening and a second opening; 
 a first cathode flow path plate having the first cathode flow path connected to the first opening, a third opening connected to the first cathode flow path, and a fourth opening connected to the second opening; 
 a first anode flow path plate having the first anode flow path connected to the second opening, a fifth opening connected to the first opening, and a sixth opening connected to the first anode flow path; 
 the first cathode current collector having a seventh opening connected to the third opening and an eighth opening connected to the fourth opening; and 
 the first anode current collector having a ninth opening connected to the fifth opening and a tenth opening connected to the sixth opening; and 
   the second electrolysis cell comprises:
 a second membrane electrode assembly having the second cathode, the second anode, and the second diaphragm; 
 a second supporting plate surrounding the second membrane electrode assembly and having an eleventh opening and a twelfth opening; 
 a second cathode flow path plate having the second cathode flow path connected to the eleventh opening, a thirteenth opening connected to the second cathode flow path, and a fourteenth opening connected to the twelfth opening; 
 a second anode flow path plate having the second anode flow path connected to the twelfth opening, a fifteenth opening connected to the eleventh opening, and a sixteenth opening connected to the second anode flow path; 
 the second cathode current collector having a seventeenth opening connected to the thirteenth opening and an eighteenth opening connected to the fourteenth opening; and 
 the second anode current collector having a nineteenth opening connected to the fifteenth opening and a twentieth opening connected to the sixteenth opening. 
   
     
     
         17 . The device according to  claim 16 , further comprising
 an insulating layer provided between the first electrolysis cell and the second electrolysis cell and having a twenty-first opening connecting the ninth opening and the fourteenth opening, and a twenty-second opening connecting the tenth opening and the thirteenth opening.   
     
     
         18 . An electrolysis system comprising the device according to  claim 1 . 
     
     
         19 . A method of operating an electrolysis device,
 the device comprising:
 a first electrolysis cell configured to reduce a reducible material and to oxidize an oxidizable material; 
 a second electrolysis cell configured to reduce the reducible material and to oxidize the oxidizable material; 
 a first supply source configured to supply a first fluid to the first electrolysis cell and the second electrolysis cell, the first fluid containing a gas of the reducible material; 
 a second supply source configured to supply a second fluid to the first electrolysis cell and the second electrolysis cell, the second fluid containing a liquid of the oxidizable material; and 
 at least one power supply configured to supply a first power supply current to the first electrolysis cell and to supply a second power supply current to the second electrolysis cell, 
   the method comprising:   supplying the first fluid to the first electrolysis cell and the second electrolysis cell, and supplying the second fluid to the first electrolysis cell and the second electrolysis cell; and   supplying the first power supply current to the first electrolysis cell to reduce the reducible material, and supplying the second power supply current to the second electrolysis cell to reduce the reducible material, wherein   a current density of a current flowing through the second electrolysis cell when reducing the reducible material is higher than a current density of a current flowing through the first electrolysis cell when reducing the reducible material.   
     
     
         20 . The method according to  claim 19 , wherein
 the first fluid contains a gas of carbon dioxide or a gas of nitrogen.