Carbon dioxide electrolysis apparatus

Abstract

Carbon dioxide electrolysis apparatus includes: electrolysis stack having diaphragm including anion exchange type solid polymer electrolyte membrane and anode and cathode separated by diaphragm; carbon dioxide supply unit configured to supply carbon dioxide to gas flow path provided adjacent to cathode; power supply unit configured to supply electric power to stack; voltage sensor configured to detect stack voltage; temperature sensor configured to detect stack temperature; and control unit including processor and memory and configured to control power supply unit. Control unit controls power supply unit so that stack voltage becomes equal to or lower than upper limit value of stack voltage predetermined corresponding to stack temperature based on stack voltage detected by voltage sensor and stack temperature detected by temperature sensor during startup period until stack temperature reaches predetermined temperature after starting supply of electric power from power supply unit to stack.

1 . A carbon dioxide electrolysis apparatus, comprising:
 an electrolysis stack having a diaphragm including an anion exchange type solid polymer electrolyte membrane and an anode and a cathode separated by the diaphragm;   a carbon dioxide supply unit configured to supply carbon dioxide to a gas flow path provided adjacent to the cathode;   a power supply unit configured to supply electric power to the electrolysis stack;   a voltage sensor configured to detect a voltage of the electrolysis stack;   a temperature sensor configured to detect a temperature of the electrolysis stack; and   a control unit including a processor and a memory coupled to the processor and configured to control the power supply unit, wherein   the control unit controls the power supply unit so that the voltage of the electrolysis stack becomes equal to or lower than an upper limit value of the voltage of the electrolysis stack predetermined corresponding to the temperature of the electrolysis stack based on the voltage of the electrolysis stack detected by the voltage sensor and the temperature of the electrolysis stack detected by the temperature sensor during a startup period until the temperature of the electrolysis stack reaches a predetermined temperature after starting supply of the electric power from the power supply unit to the electrolysis stack.   
     
     
         2 . The carbon dioxide electrolysis apparatus according to  claim 1 , wherein
 the control unit further controls the power supply unit so that the voltage of the electrolysis stack becomes equal to or higher than a lower limit value of the voltage of the electrolysis stack predetermined corresponding to the temperature of the electrolysis stack based on the voltage of the electrolysis stack detected by the voltage sensor and the temperature of the electrolysis stack detected by the temperature sensor during the startup period.   
     
     
         3 . The carbon dioxide electrolysis apparatus according to  claim 1 , wherein
 the upper limit value is predetermined based on a degree of aging deterioration of the electrolysis stack.   
     
     
         4 . The carbon dioxide electrolysis apparatus according to  claim 2 , wherein
 the lower limit value is predetermined based on a degree of aging deterioration of the electrolysis stack.   
     
     
         5 . The carbon dioxide electrolysis apparatus according to  claim 1 , wherein
 the control unit controls the power supply unit so that the voltage of the electrolysis stack becomes equal to or lower than a target value lower than the upper limit value predetermined based on a sensor error of the voltage sensor and an electrolysis efficiency of the electrolysis stack.   
     
     
         6 . The carbon dioxide electrolysis apparatus according to  claim 5 , further comprising:
 a current sensor configured to detect a current of the electrolysis stack, wherein   the control unit controls the power supply unit so that the current of the electrolysis stack detected by the current sensor increases when the voltage of the electrolysis stack detected by the voltage sensor reaches the target value, and the current of the electrolysis stack detected by the current sensor decreases when the voltage of the electrolysis stack detected by the voltage sensor falls below the target value, during the startup period.   
     
     
         7 . The carbon dioxide electrolysis apparatus according to  claim 1 , wherein
 the control unit controls the power supply unit so as to stop supply of the electric power to the electrolysis stack when the voltage of the electrolysis stack detected by the voltage sensor reaches a maximum value predetermined based on the upper limit value.   
     
     
         8 . The carbon dioxide electrolysis apparatus according to  claim 1 , wherein
 the carbon dioxide is electrolytically reduced to produce a carbon compound in the electrolysis stack, wherein   the upper limit value is predetermined based on a theoretical electrolysis voltage value for the carbon compound produced in the electrolysis stack.