Electrochemical system

Abstract

An electrochemical system includes a purification module for separating, in real time, a reduction product reduced by an electrochemical device configured to reduce a carbon oxide. The electrochemical device includes: an electrolyte membrane including a first surface and a second surface opposite to each other; a cathode arranged in parallel with the first surface and in which the reduction product is generated; an anode arranged in parallel with the second surface; and an anolyte for exchanging electric charges with the anode and containing at least a part of the reduction product having crossed over the electrolyte membrane. The purification module includes: a first flow path for extracting the anolyte to an outside, a separation unit for separating the reduction product from the anolyte extracted to the outside, and a second flow path for supplying the anolyte from which the reduction product is separated.

What is claimed is: 
     
         1 . An electrochemical system comprising a purification module configured to separate, in real time, a reduction product reduced by an electrochemical device configured to reduce a carbon oxide, wherein
 the electrochemical device comprises:
 an electrolyte membrane comprising a first surface and a second surface that are opposite to each other; 
 a cathode arranged in parallel with the first surface of the electrolyte membrane and in which the reduction product is generated; 
 an anode arranged in parallel with the second surface of the electrolyte membrane; and 
 an anolyte for exchanging electric charges with the anode and containing at least a part of the reduction product having crossed over the electrolyte membrane, and 
   the purification module comprises:
 a first flow path configured to extract the anolyte to an outside of the electrochemical device; 
 a separation unit configured to separate the reduction product from the anolyte extracted to the outside of the electrochemical device; and 
 a second flow path configured to supply, to the electrochemical device, the anolyte from which the reduction product is separated. 
   
     
     
         2 . The electrochemical system of  claim 1 , wherein the purification module is configured to control anolyte environmental conditions in the electrochemical device to be constant. 
     
     
         3 . The electrochemical system of  claim 2 , wherein the anolyte environmental conditions controlled by the purification module comprise at least one of pH conditions, concentration conditions of the reduction product, and an amount of the anolyte. 
     
     
         4 . The electrochemical system of  claim 3 , wherein the purification module comprises:
 a pH sensor configured to measure a pH of the anolyte extracted to the outside of the electrochemical device and/or a concentration sensor configured to measure a concentration of the reduction product contained in the anolyte; and   an anolyte chamber connected to the second flow path and configured to replenish the anolyte, from which the reduction product is separated, to an inside of the electrochemical device.   
     
     
         5 . The electrochemical system of  claim 2 , wherein the purification module further comprises a third flow path connected to the first flow path and the second flow path and through which the anolyte extracted to the outside of the electrochemical device to selectively bypass the separation unit. 
     
     
         6 . The electrochemical system of  claim 1 , wherein the separation unit comprises a pervaporation unit or a vacuum membrane distillation unit. 
     
     
         7 . The electrochemical system of  claim 1 , wherein the reduction product comprises a multicarbon compound comprising at least one of methanol, ethanol, 1-propanol, 2-propanol, formic acid, acetic acid, acetaldehyde, and ethylene glycol. 
     
     
         8 . The electrochemical system of  claim 7 , wherein the reduction product comprises ethanol. 
     
     
         9 . The electrochemical system of  claim 1 , wherein the anolyte comprises at least one of KHCO 3 , KOH, and H 2 SO 4 . 
     
     
         10 . The electrochemical system of  claim 1 , wherein the electrochemical device comprises a membrane electrode assembly (MEA) or a flow cell. 
     
     
         11 . A method of controlling anolyte environmental conditions in an electrochemical device configured to reduce a carbon oxide, the method comprising:
 circulating an anolyte to communicate with a purification module arranged outside the electrochemical device;   measuring, by the purification module, the anolyte environmental conditions;   separating, by a separation unit in the purification module, a reduction product from the anolyte, when the anolyte environmental conditions do not satisfy a predetermined criterion; and   supplying the anolyte, from which the reduction product is separated, back to an inside of the electrochemical device.   
     
     
         12 . The method of  claim 11 , wherein the anolyte environmental conditions comprise pH conditions and/or concentration conditions of the reduction product. 
     
     
         13 . The method of  claim 12 , wherein the measuring, by the purification module, of the anolyte environmental conditions comprises measuring, by a detection sensor disposed on a first flow path arranged in a front end of the separation unit, the anolyte environmental conditions. 
     
     
         14 . The method of  claim 12 , wherein the measuring, by the purification module, of the anolyte environmental conditions comprises measuring, by a detection sensor disposed on a second flow path arranged in a rear end of the separation unit, the anolyte environmental conditions. 
     
     
         15 . The method of  claim 12 , wherein a case where the anolyte environmental conditions do not satisfy the predetermined criterion comprises a case where a pH of the anolyte extracted to an outside of the electrochemical device is less than or equal to a first preset value or a case where a concentration of the reduction product is greater than or equal to a second preset value. 
     
     
         16 . The method of  claim 15 , further comprising, after the measuring, by the purification module, of the anolyte environmental conditions, when the pH of the anolyte exceeds the first preset value or the concentration of the reduction product is less than the second preset value, supplying, by the purification module, the anolyte, extracted to the outside of the electrochemical device, back to the electrochemical device without passing through the separation unit.