Electrochemical Utilization of Carbon Dioxide

Abstract

Some embodiments include a method of electrochemical utilization of carbon dioxide including: delivering an electrolyte into a first cathode subspace of a carbon dioxide electrolysis cell including a first cathode arranged therein such that it defines a first cathode subspace and a second cathode subspace; delivering carbon dioxide into the second cathode subspace; reducing the carbon dioxide to a product gas; removing the catholyte from the first cathode subspace and the product gas out of the second cathode subspace separately from one another; combining the product gas and the catholyte downstream of the carbon dioxide electrolysis; and separating non-reduced carbon dioxide from the product gas with the catholyte acting as an absorbent. The electrolyte comprises a catholyte.

What is claimed is: 
     
         1 . A method of electrochemical utilization of carbon dioxide, the method comprising:
 delivering a first electrolyte into a first cathode subspace of a carbon dioxide electrolysis cell having a first anode space and a first cathode space separated by a first membrane, the first cathode space including a first cathode arranged therein such that it defines a first cathode subspace and a second cathode subspace, where the first cathode subspace adjoins the first membrane;   wherein the first electrolyte comprises a first catholyte in the electrolysis cell;   delivering carbon dioxide into the second cathode subspace;   reducing the carbon dioxide to a first product gas in the second cathode subspace;   removing the first catholyte from the first cathode subspace and the product gas out of the second cathode subspace separately from one another;   combining the first product gas and the first catholyte downstream of the carbon dioxide electrolysis; and   separating non-reduced carbon dioxide from the first product gas with the first catholyte acting as an absorbent.   
     
     
         2 . The method as claimed in  claim 1 , further comprising combining the first product gas and the first catholyte in a gas scrubber. 
     
     
         3 . The method as claimed in  claim 1 , wherein the first electrolyte is delivered from a regeneration vessel to serve as a first anolyte in the anode space. 
     
     
         4 . The method as claimed in  claim 3 , wherein:
 a portion of the first catholyte basifies during reduction of the carbon dioxide and a portion of the first anolyte acidifies during the reduction of the carbon dioxide; and   the basified portion of the first catholyte and the acidified portion of the first anolyte are returned to the regeneration vessel.   
     
     
         5 . The method as claimed in  claim 1 , wherein the product gas comprises at least one of carbon monoxide, ethene, methane, or ethane. 
     
     
         6 . The method as claimed in  claim 3 , further comprising returning carbon dioxide released in the regeneration vessel to the carbon dioxide electrolysis. 
     
     
         7 . The method as claimed in  claim 1 , wherein the electrolyte comprises at least one of potassium or ammonium. 
     
     
         8 . An apparatus for electrochemical utilization of carbon dioxide, the apparatus comprising:
 a carbon dioxide electrolysis cell for reducing carbon dioxide to a first product gas;   first anode space within the electrolysis cell;   a first cathode space within the electrolysis cell;   a first membrane between the first anode space and the first cathode space;   a two-dimensional cathode in the first cathode space separating a first cathode subspace from a second cathode subspace;   wherein the first cathode subspace adjoins the first membrane;   a first conduit into the second cathode subspace for delivering carbon dioxide into the second cathode subspace;   a second conduit into the second cathode subspace for delivering a first electrolyte comprising a first catholyte;   a fourth conduit from the first cathode subspace into a gas scrubber for the first catholyte;   a fifth conduit from the second cathode subspace to the gas scrubber for delivering the first product gas separately from the first catholyte;   wherein the first product gas comprises non-reduced carbon dioxide;   the gas scrubbing apparatus configured to separate the non-reduced carbon dioxide from the first product gas using the first catholyte as an absorber.   
     
     
         9 . The apparatus as claimed in  claim 8 , further comprising a third conduit from a regeneration vessel into the first anode space for delivering the first electrolyte to serve as the first anolyte; and
 wherein the second conduit connects the regeneration vessel to the first cathode subspace.   
     
     
         10 . The apparatus as claimed in  claim 8 , further comprising an eighth conduit from the gas scrubber to the regeneration vessel for guiding the first catholyte. 
     
     
         11 . The apparatus as claimed in  claim 8  further comprising a sixth conduit from the regeneration vessel to an inlet of the second cathode space for returning the carbon dioxide from the regeneration vessel into the carbon dioxide electrolysis cell. 
     
     
         12 . The apparatus as claimed in  claim 8 , wherein the first cathode comprises a gas diffusion electrode. 
     
     
         13 . The apparatus as claimed in  claim 8 , wherein the gas scrubbing apparatus comprises random packings or a structured packing. 
     
     
         14 . The apparatus as claimed in  claim 8 , further comprising a ninth conduit from the anode space into the regeneration vessel for delivering the first anolyte.