Electrochemical reaction device and method of operating electrochemical reaction device

Abstract

An electrochemical reaction device includes: a structure that includes: a cathode; an anode; a diaphragm, a cathode chamber; and an anode chamber; a first to a fourth flow path through which a first to fourth fluid flows respectively; at least one controller selected from a first and a second flow rate controller, a first and a second pressure controller, a temperature controller and a power supply, the controller including the first flow rate controller; a gas/liquid separator in the middle of the fourth flow path; a first flowmeter that measures a flow rate of the third fluid; a second flowmeter that measures a flow rate of the fourth fluid; and a control device that measures the sum of the flow rates of the first, third and fourth fluids and controls the controller according to the sum to control a pressure difference between the chambers.

What is claimed is: 
     
         1 . An electrochemical reaction device comprising:
 an electrochemical reaction structure comprising:
 a cathode having a reduction catalyst that promotes a reduction reaction of reducing carbon dioxide to produce a carbon compound; 
 an anode having an oxidation catalyst that promotes an oxidation reaction of oxidizing water to produce oxygen; 
 a diaphragm between the cathode and the anode, 
 a cathode chamber facing on the cathode; and 
 an anode chamber facing on the anode; 
   a first flow path through which a first fluid flows, the first flow path being connected to an inlet of the cathode chamber, and the first fluid being supplied to the cathode chamber and containing the carbon dioxide;   a second flow path through which a second fluid flows, the second flow path being connected to an inlet of the anode chamber, the second fluid being supplied to the anode chamber and containing the water;   a third flow path through which a third fluid flows, the third flow path being connected to an outlet of the cathode chamber, and the third fluid being discharged from the cathode chamber and containing the carbon compound;   a fourth flow path through which a fourth fluid flows, the fourth flow path being connected to an outlet of the anode chamber, and the fourth fluid being discharged from the anode chamber and containing the water and the oxygen;   at least one controller selected from the group consisting of a first flow rate controller, a second flow rate controller, a first pressure controller, a second pressure controller, a temperature controller and a power supply, the first flow rate controller being configured to control a flow rate of the first fluid flowing through the first flow path, the second flow rate controller being configured to control a flow rate of the second fluid flowing through the second flow path, the first pressure controller being configured to control a pressure of the third flow path, the second pressure controller being configured to control a pressure of the fourth flow path, the temperature controller being configured to control a temperature of the electrochemical reaction structure, the power supply being configured to control a current or a voltage to be supplied to the electrochemical reaction structure, and the at least one controller including the first flow rate controller;   a gas/liquid separator provided in the middle of the fourth flow path and configured to process the fourth fluid to separate a liquid containing the water from the fourth fluid;   a first flowmeter configured to measure a flow rate of the third fluid flowing through the third flow path;   a second flowmeter configured to measure a flow rate of the processed fourth fluid flowing through the fourth flow path; and   a control device connected to the at least one controller, the first flowmeter and the second flowmeter, the control device being configured to measure a sum of the flow rate of the first fluid flowing through the first flow path, the flow rate of the third fluid flowing through the third flow path, and the flow rate of the processed fourth fluid flowing through the fourth flow path, and being configured to control the at least one controller according to the sum to control a pressure difference between the cathode chamber and the anode chamber.   
     
     
         2 . The electrochemical reaction device according to  claim 1 , further comprising:
 a humidifier provided in the middle of the first flow path and configured to humidify carbon dioxide in the first fluid.   
     
     
         3 . The electrochemical reaction device according to  claim 1 , further comprising:
 a dehydrator provided in the middle of the third flow path so as to precede the first flowmeter, and configured to process the third fluid to separate the water from the third fluid.   
     
     
         4 . The electrochemical reaction device according to  claim 1 , wherein
 the control device is configured to control the first flow rate controller according to the sum, and is configured to control the flow rate of the first fluid flowing through the first flow path to control the pressure difference.   
     
     
         5 . The electrochemical reaction device according to  claim 1 , wherein
 the at least one controller includes:   the first pressure controller; and   the second pressure controller, and   the control device is configured to control the first pressure controller according to the sum to control the pressure of the third flow path, and to control the second pressure controller according to the sum to control the pressure of the fourth flow path, and thus control the pressure difference.   
     
     
         6 . The electrochemical reaction device according to  claim 1 , wherein
 the at least one controller includes the second flow rate controller, and   the control device is configured to control the second flow rate controller according to the sum, and is configured to control the flow rate of the second fluid flowing through the second flow path to control the pressure difference.   
     
     
         7 . The electrochemical reaction device according to  claim 1 , wherein
 the at least one controller includes the temperature controller, and   the control device is configured to control the temperature controller according to the sum, and is configured to control the temperature of the electrochemical reaction structure to control the pressure difference.   
     
     
         8 . The electrochemical reaction device according to  claim 7 , wherein
 the temperature controller includes a heater configured to heat the electrochemical reaction structure.   
     
     
         9 . The electrochemical reaction device according to  claim 1 , wherein
 the at least one controller includes the power supply, and   the control device is configured to control the power supply according to the sum, and is configured to control the current or the voltage to be supplied to the electrochemical reaction structure to control the pressure difference.   
     
     
         10 . The electrochemical reaction device according to  claim 1 , wherein
 the control device is configured to compare a first data indicating the sum with a second data to be stored in the control device, and is configured to control the at least one controller according to a comparison result to control the pressure difference.   
     
     
         11 . The electrochemical reaction device according to  claim 1 , wherein
 the control device is configured to analyze variations in the sum over time, and is configured to control the at least one controller according to a result of the analyzation to control the pressure difference.   
     
     
         12 . A method of operating an electrochemical reaction device,
 the electrochemical reaction device comprising an electrochemical reaction structure,   the electrochemical reaction structure comprising:
 a cathode having a reduction catalyst that promotes a reduction reaction of reducing carbon dioxide to produce a carbon compound; 
 an anode having an oxidation catalyst that promotes an oxidation reaction of oxidizing water to produce oxygen; 
 a diaphragm between the cathode and the anode, 
 a cathode chamber facing on the cathode; and 
 an anode chamber facing on the anode; 
   a first flow path through which a first fluid flows, the first flow path being connected to an inlet of the cathode chamber, and the first fluid being supplied to the cathode chamber and containing the carbon dioxide;   a second flow path through which a second fluid flows, the second flow path being connected to an inlet of the anode chamber, and the second fluid being supplied to the anode chamber and containing the water;   a third flow path through which a third fluid flows, the third flow path being connected to an outlet of the cathode chamber, and the third fluid being discharged from the cathode chamber and containing the produced carbon compound;   a fourth flow path through which a fourth fluid flows, the fourth flow path being connected to an outlet of the anode chamber, and the fourth fluid being discharged from the anode chamber and containing the water and the produced oxygen;   at least one controller selected from the group consisting of a first flow rate controller, a second flow rate controller, a first pressure controller, a second pressure controller, a temperature controller and a power supply, the first flow rate controller being configured to control a flow rate of the first fluid flowing through the first flow path, the second flow rate controller being configured to control a flow rate of the second fluid flowing through the second flow path, the first pressure controller being configured to control a pressure of the third flow path, the second pressure controller being configured to control a pressure of the fourth flow path, the temperature controller being configured to control a temperature of the electrochemical reaction structure, the power supply being configured to control a current or a voltage to be supplied to the electrochemical reaction structure, and the at least one controller including the first flow rate controller;   a gas/liquid separator provided in the middle of the fourth flow path and configured to process the fourth fluid to separate a liquid containing the water from the fourth fluid;   a first flowmeter configured to measure a flow rate of the third fluid flowing through the third flow path; and   a second flowmeter configured to measure a flow rate of the processed fourth fluid flowing through the fourth flow path,   the method comprising:   supplying the first fluid to the cathode chamber, supplying the second fluid to the anode chamber, and supplying a current or a voltage to the electrochemical reaction structure, to reduce the carbon dioxide by the cathode to produce the carbon compound and to reduce the water by the anode to produce the oxygen; and   measuring the sum of the flow rate of the first fluid flowing through the first flow path, the flow rate of the third fluid flowing through the third flow path, and the flow rate of the processed fourth fluid flowing through the fourth flow path and controlling the at least one controller according to the sum to control a pressure difference between the cathode chamber and the anode chamber.   
     
     
         13 . The method according to  claim 12 , wherein
 a pressure in the cathode chamber is controlled to a range of 0 PaG or more and 300 KPaG or less,   a pressure in the anode chamber is controlled to 0 PaG or more and 300 KPaG or less,   the pressure difference is controlled to 0 PaG or more and 150 KPaG or less, and   the pressure in the cathode chamber is higher than the pressure in the anode chamber.   
     
     
         14 . The method according to  claim 12 , wherein
 the electrochemical reaction device further comprises at least one selected from the group consisting of a humidifier and a dehydrator,   the humidifier is provided in the middle of the flow path and is configured to humidify carbon dioxide in the first fluid, and   the dehydrator is provided in the middle of the third flow path so as to precede the first flowmeter and is configured to process the third fluid to separate the water from the third fluid.   
     
     
         15 . The method according to  claim 12 , wherein
 the electrochemical reaction device further comprises a control device, and   the control device is configured to control the first flow rate controller according to the sum and is configured to control the flow rate of the first fluid flowing through the first flow path to control the pressure difference.   
     
     
         16 . The method according to  claim 12 , wherein
 the electrochemical reaction device further comprises a control device,   the at least one controller includes:   the first pressure controller; and   the second pressure controller, and   the control device is configured to control the first pressure controller according to the sum to control the pressure of the third flow path and controls the second pressure controller according to the sum to control the pressure of the fourth flow path, and thereby controls the pressure difference.   
     
     
         17 . The method according to  claim 12 , wherein
 the electrochemical reaction device further comprises a control device,   the at least one controller includes the second flow rate controller, and   the control device is configured to control the second flow rate controller according to the sum, and is configured to control the flow rate of the second fluid flowing through the second flow path to control the pressure difference.   
     
     
         18 . The method according to any  claim 12 , wherein
 the electrochemical reaction device further comprises a control device,   the at least one controller includes the temperature controller, and   the control device is configured to control the temperature controller according to the sum, and is configured to control the temperature of the electrochemical reaction structure to control the pressure difference.   
     
     
         19 . The electrochemical reaction device according to  claim 12 , wherein
 the electrochemical reaction device further comprises a control device,   the at least one controller includes the power supply, and   the control device is configured to control the power supply according to the sum, and is configured to control the current or the voltage to be supplied to the electrochemical reaction structure to control the pressure difference.   
     
     
         20 . The method according to  claim 12 , wherein
 the electrochemical reaction device further includes a control device, and   the control device is configured to compare a first data indicating the sum with a second data to be stored in the control device, and is configured to control the at least one controller according to a comparison result to control the pressure difference, or   the control device is configured to analyze variations in the sum over time, and is configured to control the at least one controller according to a result of the analyzation to control the pressure difference.