SYSTEM AND METHOD FOR HIGH CONCENTRATION OF MULTIELECTRON PRODUCTS OR CO IN ELECTROLYZER OUTPUT
Systems and methods for increasing the concentration of a desired product in gas phase output streams of CO x electrolyzers are described.
1 . A system for producing a gas phase multielectron product, comprising:
a carbon dioxide (CO 2 ) reduction reactor comprising a membrane electrode assembly that comprises one or more ion conductive polymer layers and a cathode catalyst for facilitating chemical reduction of carbon dioxide to carbon monoxide;
a carbon oxide (CO x ) reduction reactor comprising an anion-exchange membrane (AEM)-only membrane electrode assembly (MEA) that comprises one or more ion conductive polymer layers and a cathode catalyst for facilitating chemical reduction of carbon oxide to the gas phase multielectron product, the CO x reduction reactor configured to receive an intermediate product stream comprising carbon monoxide (CO) and unreacted CO 2 from the CO 2 reduction reactor, reduce CO to the multielectron gas phase product, convert at least some of the unreacted CO 2 to bicarbonate, transport the bicarbonate to the anode side of the AEM-only MEA, and output a cathode-side gas phase product stream comprising the multielectron product, wherein the amount of CO 2 in the gas phase product stream is less than the amount in the intermediate gas phase product stream.
2 . The system of claim 1 , wherein the CO 2 reduction reactor comprises a bipolar MEA.
3 . The system of claim 1 , wherein the CO 2 reduction reactor comprises a cation exchange membrane-only MEA.
4 . The system of claim 1 , wherein the CO 2 reduction reactor and the CO x reduction reactor each comprise a stack of electrochemical cells each comprising an MEA.
5 . The system of claim 1 , wherein the CO x reduction reactor is configured to output an anode-side stream comprising O 2 and CO 2 , the system further comprising a separator configured to separate the CO 2 and the O 2 in the anode-side stream; and a mixing unit configured to mix fresh CO 2 with separated CO 2 for inlet to the CO 2 reduction reactor.
6 . The system of claim 1 , wherein the CO x reduction reactor is configured to output an anode-side stream comprising CO 2 , the system further a recycle loop configured to recycle the CO 2 from the anode-side stream to the CO 2 reduction reactor.
7 . The system of claim 1 , wherein the CO x reduction reactor is configured to output an anode-side stream comprising CO 2 and O 2 , the system further comprising a separator configured to separate the CO 2 and the O 2 in the anode-side stream; and a mixing unit configured to mix fresh CO 2 with separated CO 2 for inlet to the CO 2 reduction reactor.
8 . The system of claim 1 , wherein the cathode catalyst for facilitating chemical reduction of carbon dioxide to carbon monoxide comprises gold.
9 . The system of claim 1 , wherein the cathode catalyst for facilitating chemical reduction of carbon oxide to the gas phase multielectron product comprises copper.
10 . The system of claim 1 , wherein the gas phase multielectron product is methane (CH 4 ).
11 . The system of claim 1 , wherein the gas phase multielectron product is ethylene (CH 2 CH 2 ).
12 . A system for producing CO, comprising:
a carbon dioxide (CO 2 ) reduction reactor comprising a membrane electrode assembly that comprises one or more ion conductive polymer layers and a cathode catalyst for facilitating chemical reduction of carbon dioxide to carbon monoxide;
a carbon oxide (CO x ) reduction reactor comprising an anion-exchange membrane (AEM)-only membrane electrode assembly (MEA) that comprises one or more ion conductive polymer layers and a cathode catalyst for facilitating chemical reduction of carbon dioxide, the CO x reduction reactor configured to receive an intermediate product stream comprising carbon monoxide (CO) and unreacted CO 2 from the CO 2 reduction reactor, convert at least some of the unreacted CO 2 to bicarbonate, transport the bicarbonate to the anode side of the AEM-only MEA, and output a cathode-side gas phase product stream comprising CO, wherein the amount of CO 2 in the gas phase product stream is less than the amount in the intermediate gas phase product stream.
13 . The system of claim 12 , wherein the CO 2 reduction reactor comprises a bipolar MEA.
14 . The system of claim 12 , wherein the CO 2 reduction reactor comprises a cation exchange membrane-only MEA.
15 . The system of claim 12 , wherein the CO 2 reduction reactor comprises a stack of electrochemical cells each comprising an MEA and the CO x reduction reactor comprises a stack of electrochemical cells each comprising an MEA.
16 . The system of claim 12 , wherein the CO x reduction reactor is configured to receive a carbon-containing anode-side feed stream.
17 . A system for producing a gas phase product, comprising:
a carbon dioxide (CO 2 ) reduction reactor comprising an anion-exchange membrane (AEM)-only membrane electrode assembly (MEA) that comprises a cathode catalyst for facilitating chemical reduction of CO 2 to the gas phase product; the CO 2 reduction reactor configured to reduce CO 2 to the gas phase product, convert at least some unreacted CO 2 to bicarbonate, transport the bicarbonate to the anode side of the AEM-only MEA for reaction to CO 2 , output a cathode-side gas phase product stream comprising the product, and output an anode-side stream comprising O 2 and CO 2 ;
a separator configured to separate the CO 2 and the O 2 in the anode-side stream; and
a mixing unit configured to mix fresh CO 2 with separated CO 2 for inlet to the CO 2 reduction reactor.
18 . The system of claim 17 , wherein the gas phase product is carbon monoxide (CO).
19 . The system of claim 17 , wherein the gas phase product is a gas phase multielectron product.
20 . The system of claim 19 , wherein the gas phase multielectron product is methane (CH 4 ).
21 .- 59 . (canceled)