Systems and methods for electrochemical generation of syngas and other useful chemicals

Patent metadata

Field	Value
Publication number	US-12006580-B2
Application number	US-201917050319-A
Country	US
Kind code	B2
Filing date	Apr 25, 2019
Priority date	Apr 25, 2018
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

Processes and apparatus for electrocatalytically converting carbon dioxide emissions and/or ambient carbon dioxide into useful chemicals are described. The process may include: removing carbon dioxide from ambient air through a carbon capture technique, supplying a carbonate or bicarbonate aqueous solution as cathode feed to a cathode of an electrolytic cell comprising a membrane electrode assembly which includes a bipolar membrane separating an anode from the cathode, and applying an electrical potential difference between the cathode and the anode of the membrane electrode assembly to electrocatalytically reduce the carbonate or bicarbonate aqueous solution to carbon monoxide or another useful chemical.

First claim

What is claimed is:

1. A carbon capture method comprising:
removing carbon dioxide from a source by absorbing and chemically reacting gaseous carbon dioxide to form bicarbonate and/or carbonate in an aqueous solution;
supplying a catholyte comprising the aqueous solution at a cathode of an electrochemical reactor comprising an anode and the cathode separated by a bipolar membrane and applying a potential difference between the anode and the cathode to cause an electrochemical reaction yielding product gas comprising one or both of gas phase carbon dioxide and gas phase carbon monoxide, wherein the supplying of the catholyte at the cathode comprises supplying the aqueous solution in the absence of an additional supply of carbon dioxide gas; and
separating the product gas from the aqueous solution.

2. The method according to claim 1 comprising, at the cathode of the electrochemical reactor, generating hydrogen gas wherein the product gas comprises the hydrogen gas.

3. The method according to claim 1 wherein the aqueous solution comprises bicarbonate at a concentration of at least 3 moles/liter.

4. The method according to claim 1 wherein a current flowing in the electrochemical reactor as a result of the applied potential has a current density at the cathode of at least 100 mA/cm 2 .

5. The method according to claim 1 wherein the electrochemical reactor is operated at a temperature not exceeding 150° C. and not exceeding a boiling point of the aqueous solution.

6. The method according to claim 1 comprising maintaining a pressure of the aqueous solution at the cathode of the electrochemical reactor at 2 atmospheres or less.

7. The method according to claim 1 comprising flowing the aqueous solution through a cathode chamber of the electrochemical reactor.

8. The method according to claim 1 wherein the aqueous solution has a pH above 7.

9. The method according to claim 8 wherein the aqueous solution comprises a strong base.

10. The method according to claim 8 wherein the pH of the aqueous solution is at least 8.0.

11. The method according to claim 8 wherein the pH of the aqueous solution when supplied for chemically reacting the gaseous carbon dioxide is in the range of 8 to 10.

12. The method according to claim 1 wherein the aqueous solution has a first pH at an input of the electrochemical reactor and a second pH at an output of the electrochemical reactor and the second pH is higher than the first pH.

13. The method according to claim 1 comprising controlling a composition of the product gas by adjusting a magnitude of the potential difference.

14. The method according to claim 13 wherein a concentration of CO 2 in the aqueous solution is below 7 mM.

15. The method according to claim 1 wherein the product gas comprises CO 2 , CO and H 2 .

16. The method according to claim 15 wherein the product gas comprises no more than 50% CO 2 .

17. The method according to claim 15 wherein a molar ratio of CO to H 2 in the product gas is greater than 1.

18. The method according to claim 15 wherein a molar ratio of CO to H 2 in the product gas is less than 1.

19. The method according to claim 1 wherein absorbing and chemically reacting the gaseous carbon dioxide comprises flowing the gaseous carbon dioxide through a filter wetted by the aqueous solution.

20. The method according to claim 1 wherein the aqueous solution comprises a caustic alkaline solution.

21. The method according to claim 1 wherein the aqueous solution comprises an enzyme that is active for promoting the chemical reaction of the carbon dioxide to yield bicarbonate and/or carbonate.

22. The method according to claim 21 wherein the enzyme comprises a carbonic anhydrase enzyme catalyst.

23. The method according to claim 1 comprising circulating the aqueous solution back to absorb and chemically react with more gaseous carbon dioxide after separating the product gas from the aqueous solution.

24. A carbon capture method comprising:
removing carbon dioxide from a source by absorbing and chemically reacting gaseous carbon dioxide to form bicarbonate and/or carbonate in an aqueous solution;
supplying a catholyte comprising the aqueous solution at a cathode of an electrochemical reactor comprising an anode and the cathode separated by a bipolar membrane and applying a potential difference between the anode and the cathode, wherein the supplying of the catholyte at the cathode comprises supplying the aqueous solution in the absence of an additional supply of carbon dioxide gas;
electrochemically dissociating, at the bipolar membrane, water to form hydrogen ions;
transporting the hydrogen ions towards the cathode;
reacting the bicarbonate and/or carbonate ions in the aqueous solution with the hydrogen ions to form carbon dioxide gas;
electrochemically reducing the carbon dioxide gas to form a product gas; and
separating the product gas from the aqueous solution.

Assignees

• Univ British Columbia

Inventors

• Berlinguette Curtis
• Salvatore Danielle
• Li Tengfei
• Goldman Maxwell
• Lees Eric

Classifications

• C25B15/08

  Supplying or removing reactants or electrolytes; Regeneration of electrolytes · CPC title

• C25B1/02

  Hydrogen or oxygen · CPC title

• B01D2257/504

  Carbon dioxide · CPC title

• B01D2252/602

  Activators, promoting agents, catalytic agents or enzymes · CPC title

• B01D53/73

  After-treatment of removed components · CPC title