Carbon dioxide electrolysis apparatus and carbon dioxide electrolysis method

Abstract

A carbon dioxide electrolysis apparatus according to an embodiment includes an electrolysis cell including a cathode electrode to which carbon dioxide gas is supplied, an anode electrode, and an electrolyte membrane interposed between the cathode electrode and the anode electrode, a current supply unit that supplies a current to the electrolysis cell, and a control unit. A value obtained by dividing the current supplied to the electrolysis cell by the planar effective area of the electrolysis cell is defined as a current density. The control unit controls the current supply unit such that the current density is 10 mA/cm2 to 1,000 mA/cm2.

1 . A carbon dioxide electrolysis apparatus that performs electrolysis of carbon dioxide gas, the apparatus comprising:
 an electrolysis cell including a cathode electrode to which the carbon dioxide gas is supplied, an anode electrode, and an electrolyte membrane interposed between the cathode electrode and the anode electrode;   a current supply unit that supplies a current to the electrolysis cell; and   a control unit, wherein   a value obtained by dividing the current supplied to the electrolysis cell by a planar effective area of the electrolysis cell is defined as a current density, and   the control unit controls the current supply unit such that the current density becomes 10 mA/cm 2  to 1,000 mA/cm 2 .   
     
     
         2 . The carbon dioxide electrolysis apparatus according to  claim 1 , wherein the control unit controls the current supply unit such that the current density is 100 mA/cm 2  to 1,000 mA/cm 2 . 
     
     
         3 . The carbon dioxide electrolysis apparatus according to  claim 1 , further comprising:
 a carbon dioxide gas flow rate adjustment unit that adjusts a supply flow rate of the carbon dioxide gas to the cathode electrode, wherein   a minimum flow rate of the carbon dioxide gas when the total amount of electricity per unit time at a predetermined current density is used in the electrolytic reaction from carbon dioxide to carbon monoxide is defined as a theoretical carbon dioxide gas flow rate, and the ratio of the supply flow rate of the carbon dioxide gas to the theoretical carbon dioxide gas flow rate is defined as a flow rate ratio, and   the control unit controls the carbon dioxide gas flow rate adjustment unit such that the flow rate ratio is 50% to 500%.   
     
     
         4 . The carbon dioxide electrolysis apparatus according to  claim 1 , further comprising
 an input unit for inputting a concentration of the carbon dioxide gas supplied to the cathode electrode, wherein   the control unit controls the current supply unit to adjust the current density based on the concentration of the carbon dioxide gas input to the input unit.   
     
     
         5 . The carbon dioxide electrolysis apparatus according to  claim 3 , wherein
 the control unit controls the carbon dioxide gas flow rate adjustment unit such that the flow rate ratio is 100% to 200%.   
     
     
         6 . The carbon dioxide electrolysis apparatus according to  claim 3 , further comprising:
 an inert gas supply unit that supplies an inert gas to be mixed with the carbon dioxide gas; and   an inert gas flow rate adjustment unit that adjusts a supply flow rate of an inert gas to be mixed with the carbon dioxide gas, wherein   the control unit controls the inert gas flow rate adjustment unit to mix the inert gas with the carbon dioxide gas.   
     
     
         7 . A carbon dioxide electrolysis apparatus that performs electrolysis of carbon dioxide gas, the apparatus comprising:
 an electrolysis cell including a cathode electrode to which the carbon dioxide gas is supplied, an anode electrode, and an electrolyte membrane interposed between the cathode electrode and the anode electrode;   a carbon dioxide gas flow rate adjustment unit that adjusts a supply flow rate of the carbon dioxide gas to the cathode electrode; and   a control unit, wherein   a value obtained by dividing a current supplied to the electrolysis cell by a planar effective area of the electrolysis cell is defined as a current density,   a minimum flow rate of the carbon dioxide gas when the total amount of electricity per unit time at a predetermined current density is used in the electrolytic reaction from carbon dioxide to carbon monoxide is defined as a theoretical carbon dioxide gas flow rate, and the ratio of the supply flow rate of the carbon dioxide gas to the theoretical carbon dioxide gas flow rate is defined as a flow rate ratio, and   the control unit controls the carbon dioxide gas flow rate adjustment unit such that the flow rate ratio is 50% to 500%.   
     
     
         8 . The carbon dioxide electrolysis apparatus according to  claim 7 , wherein
 the control unit controls the carbon dioxide gas flow rate adjustment unit such that the flow rate ratio is 100% to 200%.   
     
     
         9 . The carbon dioxide electrolysis apparatus according to  claim 7 , further comprising:
 an inert gas supply unit that supplies an inert gas to be mixed with the carbon dioxide gas; and   an inert gas flow rate adjustment unit that adjusts a supply flow rate of an inert gas to be mixed with the carbon dioxide gas, wherein   the control unit controls the inert gas flow rate adjustment unit to mix the inert gas with the carbon dioxide gas.   
     
     
         10 . A carbon dioxide electrolysis method using a carbon dioxide electrolysis apparatus that performs electrolysis of carbon dioxide gas and includes an electrolysis cell including a cathode electrode to which the carbon dioxide gas is supplied, an anode electrode, and an electrolyte membrane interposed between the cathode electrode and the anode electrode, the method comprising:
 supplying the carbon dioxide gas to the cathode electrode;   supplying a current to the electrolysis cell; and   increasing an output of the carbon dioxide electrolysis apparatus, wherein   a value obtained by dividing a current supplied to the electrolysis cell by a planar effective area of the electrolysis cell is defined as a current density, and   in the increasing of the output, the current value of the current is adjusted such that the current density becomes 10 mA/cm 2  to 1,000 mA/cm 2 .   
     
     
         11 . The carbon dioxide electrolysis method according to  claim 10 , wherein
 the current value of the current is adjusted such that the current density is 100 mA/cm 2  to 1,000 mA/cm 2  in the increasing of the power.   
     
     
         12 . The carbon dioxide electrolysis method according to  claim 10 , wherein
 a minimum flow rate of the carbon dioxide gas when the total amount of electricity per unit time at a predetermined current density is used in the electrolytic reaction from carbon dioxide to carbon monoxide is defined as a theoretical carbon dioxide gas flow rate, and the ratio of the supply flow rate of the carbon dioxide gas to the theoretical carbon dioxide gas flow rate is defined as a flow rate ratio, and   in the increasing of the output, the supply flow rate of the carbon dioxide gas is adjusted such that the flow rate ratio is 50% to 500%.   
     
     
         13 . The carbon dioxide electrolysis method according to  claim 10 , further comprising:
 inputting a concentration of the carbon dioxide gas to be supplied to the cathode electrode, wherein   in the increasing of the output, the current value of the current is adjusted based on the concentration of the carbon dioxide gas.   
     
     
         14 . The carbon dioxide electrolysis method according to  claim 12 , wherein
 in the increasing of the output, the supply flow rate of the carbon dioxide gas is adjusted such that the flow rate ratio is 100% to 200%.   
     
     
         15 . The carbon dioxide electrolysis method according to  claim 12 , wherein
 an inert gas is mixed with the carbon dioxide gas in the supplying of the carbon dioxide gas.