Electrochemical reactor for upgrading methane and small alkanes to longer alkanes and alkenes

Patent metadata

Field	Value
Publication number	US-11591699-B2
Application number	US-201917046611-A
Country	US
Kind code	B2
Filing date	Apr 12, 2019
Priority date	Apr 12, 2018
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

This application relates to new process that utilizes electrodes that incorporate acids that facilitate upgrading of methane and other low molecular weight alkanes to higher order hydrocarbon molecules, such as paraffins, olefins, and aromatics, at temperatures less than 250° C. A primary focus of the invention includes methane conversion to ethylene. The first step of the process includes acid containing electrodes that facilitate the activation of the alkane in the anode layer of the electrochemical reactor. Subsequent steps include the separation of protons from produced longer chain hydrocarbons followed by subsequent electrochemical reduction of the protons to yield hydrogen at the cathode or protons combined with oxygen at the cathode to yield water. The reaction steps in the anode upgrade methane to higher order hydrocarbon products.

First claim

We claim:

1. An apparatus for synthesizing higher order hydrocarbons from low molecular weight alkanes comprising:
(a) an anode;
(b) a cathode;
(c) an acid electrolyte separator;
(d) a catalyst;
(e) electrode binders that feature one or more acids in the anode and cathode, wherein the one or more acids is trifluoromethanesulfonic acid (CF 3 SO 3 H), fluorosulfuric acid (HSO 3 F), or an acid mixture, wherein the acid mixture is HF, HSO 3 F, and H 2 SO 4 , or a mixture of sulfuric, chlorosulfonic, or perchloric acid;
(f) a low molecular weight hydrocarbon;
(g) wherein the catalysts are comprised of platinum group metals or platinum group metal oxides, or transition metal or transition metal oxides;
(h) wherein the anode and the cathode are in electronic communication to allow flow of electrons from the anode to the cathode;
(i) wherein the low molecular weight hydrocarbon is in contact with the anode; and,
wherein synthesis of a higher order hydrocarbon occurs at a temperature less than 400° C.

2. The apparatus of claim 1 wherein the low molecular weight hydrocarbon is methane and wherein the higher order hydrocarbon is an alkane, alkene, or aromatic product.

3. The apparatus of claim 1 , wherein the one or more acids is trifluoromethanesulfonic acid (CF 3 SO 3 H) or fluorosulfuric acid (HSO 3 F).

4. The apparatus of claim 3 wherein the anode and cathode further comprises an electrically conductive support material, catalyst, and an acid containing ionomer binder.

5. The apparatus of claim 4 wherein the synthesis reaction occurs at a temperature between 100° C. and 250° C.

6. The apparatus of claim 5 wherein the cathode and anode comprise a catalyst that is selected from a group consisting of ruthenium, rhodium, palladium, osmium, iridium, and platinum metal or the metal in its oxide form.

7. The apparatus of claim 6 wherein the acid containing ionomer binder comprises a polymer host, wherein the polymer host is selected from polybenzimidazole, polycations, or blends of polybenzimidazole-polycations.

8. The apparatus of claim 7 wherein the polymer host is the blend of the polybenzimidazole-polycation, wherein the cation group is selected from quaternary ammoniums, imidazoliums, phosphoniums, or ternary sulfoniums or sulfoxniums, or tethered metal cation centers.

9. The apparatus of claim 1 , wherein the one or more acids is the acid mixture of HF, HSO 3 F, and H 2 SO 4 .

10. An apparatus for synthesizing ethylene from methane:
(a) an anode;
(b) a cathode;
(c) an acid electrolyte separator;
(d) a catalyst;
(e) electrode binders that feature one or more acids in the anode and cathode, wherein the one or more acids is trifluoromethanesulfonic acid (CF 3 SO 3 H) or fluorosulfuric acid (HSO 3 F);
(f) methane;
(g) wherein the catalysts are comprised of platinum group metals or platinum group metal oxides, or transition metal or transition metal oxides;
(h) wherein the anode and the cathode are in electronic communication to allow flow of electrons from the anode to the cathode;
(i) wherein the methane is in contact with the anode; and, wherein synthesis of ethylene occurs at a temperature less than 400° C.

11. The apparatus of claim 10 , wherein the anode and cathode further comprises an acid containing ionomer binder, wherein the acid containing ionomer binder comprises a polymer host, wherein the polymer host is selected from polybenzimidazole, polycations, or blends of polybenzimidazole-polycations.

12. The apparatus of claim 11 , wherein the polycation material is selected from a group consisting of polyaromatic or perfluorinated backbones with tethered cation groups, wherein the tethered cation groups are selected from quaternary ammoniums, imidazoliums, phosphoniums, or ternary sulfoniums or sulfoxniums, or tethered metal cation centers.

13. A method for synthesizing higher order hydrocarbons from low molecular weight alkanes comprising:
a. providing an apparatus comprising:
i. an anode;
ii. a cathode;
iii. an acid electrolyte separator;
iv. a catalyst;
v. electrode binders that feature one or more acids in the anode and cathode;
vi. a low molecular weight hydrocarbon, wherein the low molecular weight alkane is methane and wherein the higher order hydrocarbon is an alkane, alkene, or aromatic product;
vii. wherein the catalysts are comprised of platinum group metals or platinum group metal oxides, or transition metal or transition metal oxides;
viii. wherein the anode and the cathode are in electronic communication to allow flow of electrons from the anode to the cathode;
ix. wherein the low molecular weight hydrocarbon is in contact with the anode; and,
wherein synthesis of a higher order hydrocarbon occurs at a temperature less than 400° C.;
b. feeding the low molecular weight hydrocarbon the apparatus;
c. applying an electrical current to the anode;
d. removing the higher order hydrocarbon synthesized in the apparatus;
e. removing hydrogen produced in the apparatus;
wherein the anode and cathode further comprises an electrically conductive support material, catalyst, and an acid containing ionomer binder, wherein the acid containing ionomer binder comprises a polymer host, wherein the polymer host is selected from polybenzimidazole, polycations, or blends of polybenzimidazole-polycations, wherein the polycation material is selected from a group consisting of polyaromatic or perfluorinated backbones with tethered cation groups, wherein the tethered cation groups are selected from quaternary ammoniums, imidazoliums, phosphoniums, or ternary sulfoniums or sulfoxniums, or tethered metal cation centers.

14. The method of claim 13 wherein the low molecular weight alkane is selected from a group consisting of methane, ethane, propane, butane and mixtures of these.

15. The method of claim 13 wherein the one or more acids is trifluoromethanesulfonic acid (CF 3 SO 3 H), fluorosulfuric acid (HSO 3 F), or an acid mixture, wherein the acid mixture is HF, HSO 3 F, and H 2 SO 4 , or a mixture of sulfuric, chlorosulfonic, or perchloric acid.

16. The method of claim 15 wherein the synthesis reaction occurs at a temperature between 100° C. and 250° C.

17. The method of claim 16 wherein the cathode and anode comprise a catalyst that is selected from a group consisting of ruthenium, rhodium, palladium, osmium, iridium, and platinum metal or the metal in its oxide form.

18. The method of claim 13 wherein the polymer host is the blend of polybenzimidazole-polycations.

19. The method of claim 18 wherein the polycation material is selected from quaternary ammoniums, imidazoliums, phosphoniums, or ternary sulfoniums or sulfoxniums, or tethered metal cation centers.

20. The method of claim 15 , wherein the one or more acids is the acid mixture of HF, HSO 3 F, and H 2 SO 4 .

Assignees

• Univ Louisiana State
• Board Of Supervisors Of Louisiana State Univ

Inventors

• Arges Christopher George
• Flake John C
• Fang Yuxin

Classifications

• H01M8/10

  Fuel cells with solid electrolytes · CPC title

• C25B3/03

  Acyclic or carbocyclic hydrocarbons · CPC title

• C25B3/25 Primary

  Reduction · CPC title

• H01M4/92 Primary

  Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) · CPC title

• C25B11/077

  the compound being a non-noble metal oxide · CPC title