A methanation method and system

Abstract

Disclosed is a methanation method comprising an electrolyser system, the electrolyser system (20) comprising an electrolyser (10) having at least one electrolyser cell (11), at least one fuel input (1

Claims

1. A methanation method comprising providing an electrolyser system, the electrolyser system comprising an electrolyser that has at least one electrolyser cell, at least one fuel input through which fuel enters the electrolyser and at least one offgas output from which offgas exits the electrolyser, the method further comprising:supplying fuel to the at least one fuel inlet, the fuel comprising at least water and either or both carbon dioxide and carbon monoxide;operating the electrolyser system by powering the electrolyser cell with electricity to electrolyse the fuel in the at least one electrolyser cell such that a part of the water splits into hydrogen and oxygen;wherein the electrolyser is operated at a temperature at or in excess of 150 degrees C; andmethanation occurs to the carbon dioxide and / or carbon monoxide in the electrolyser.

2. The method of claim 1, wherein the fuel is a mixture of steam and carbon dioxide.

3. The method of any one of the preceding claims, wherein separate streams of steamand carbon dioxide are fed to the fuel inlet.

4. The method of any one of the preceding claims, wherein there are two offgas outputs, comprising a first for the methane and steam and a second for the oxygen.

5. The method of any one of the preceding claims, wherein the gas mixture released from the at least one offgas output is passed through a gas separation process to separate at least the methane from the gas mixture.

6. The method of claim 5, wherein the gas separation process comprises a condensation step to condense a majority of the water out of the gas mixture.

7. The method of claim 5 or claim 6, wherein the gas separation process comprises a CO2 separation step to separate a majority of the CO2 from the gas mixture.

8. The method of any one of claims 5 to 7, wherein the gas separation process comprises a H2 and / or CO separation process to separate a majority of the H2 and / or CO from the gas mixture.

9. The method of claim 8, wherein the H2 and / or CO separation process comprises a methane separation process to separate a majority of the methane from the H2 and / or CO inthe gas mixture, a majority of the CO2 and H2O having been previously been removed from the gas mixture.

10. The method of any one of the preceding claims, wherein unreacted gasses in the gas mixture are recirculated into the electrolyser via the one or more gas input.

11. The method of any one of the preceding claims, wherein the electrolyser is operated at a temperature between 500 and 600 degrees C, or more preferably between 525 and 575 degrees C, inclusive.

12. The method of any one of the preceding claims, wherein a methanation catalyst is used in the electrolyser or the at least one electrolyser cell to improve the efficiency of the methanation occurring within the electrolyser.

13. The method of claim 12, wherein the methanation catalyst is a nickel based catalyst.

14. The method of any one of the preceding claims, wherein the ratio of the fuel gases is controlled to target a ratio of methane to unreacted gases of the electrolysis and methanation processes, in the offgas gas mixture, such that at least 10% of the total volume of the gas mixture exiting the at least one offgas output is methane.

15. The method of any one of the proceeding claims, wherein heat from the methanation reaction is used to heat fluids entering the electrolyser.

16. The method of any one of the preceding claims, wherein the electrolyser is a solid oxide electrolyser.

17. The method of any one of the preceding claims, wherein the at least one electrolyser cell is part of a stack of electrolyser cells.

18. The method of any one of the preceding claims, wherein there are one or more stacks of electrolyser cells in the electrolyser.

19. An electrolyser system configured to operate using the method according to any one of the preceding claims.

20. The electrolyser system of claim 19, wherein the electrolyser comprises a methanation catalyst.

21. The electrolyser system of claim 20, wherein the methanation catalyst is located at a lower temperature region of the electrolyser or stack or cells.

22. The electrolyser system of claim 20 or claim 21, wherein the methanation catalyst is located at, near or towards an outlet end of the electrolyser cells.

23. The electrolyser system of any one of claims 19 to 22, wherein the electrolyser comprises a reverse water gas shift catalyst.

24. The electrolyser system of claim 23, wherein the methanation catalyst is located at a lower temperature region of the electrolyser or stack or cells.

25. The electrolyser system of claim 23 or claim 24, wherein the methanation catalyst is located at, near or towards an outlet end of the electrolyser cells.

26. An electrolyser system comprising an electrolyser that has at least one electrolyser cell, at least one fuel input and at least one offgas output, wherein the offgas output is connected to a methane separator for separating methane from offgas exiting the offgas output during use of the electrolyser system.

27. The electrolyser system of claim 26, wherein the electrolyser is connected to a source of steam and carbon dioxide.

28. The electrolyser system of claim 26 or claim 26, wherein the electrolyser is a solid oxide electrolyser.

29. The electrolyser system of any one of claims 26 to 28, wherein the electrolyser has an operating temperature of between 450 - 650 degrees C, inclusive.

30. The electrolyser system of any one of claims 26 to 29, wherein the at least one electrolyser cell is part of a stack of electrolyser cells.

31. The electrolyser system of any one of claims 26 to 30, wherein there are one or more stacks of electrolyser cells in the electrolyser.

32. The electrolyser system of any one of claims 26 to 31, wherein the methane separator is a methane separator with an operating temperature in excess of 400 degrees C.

33. The electrolyser system of any one of claims 26 to 32, wherein the methane separator is a methane membrane.

34. The electrolyser system of any one of claims 26 to 31, wherein the methane separator is a cryogenic separator.

35. The electrolyser system of any one of claims 26 to 31, wherein heat exchangers are provided and configured to reutilize heat from the offgas output’s gas mixture, or separated components thereof, for preheating the fuel.

36. The electrolyser system of any one of claims 26 to 35, configured to operate the method according to any one of claims 1 to 19.

37. A method for generating methane using at least one electrochemical cell, the method comprising:providing at least water and carbon dioxide as inputs to the electrochemical cell; andpowering the electrochemical cell with electrical energy to perform the at least partial conversion of the water into hydrogen and oxygen;the method further comprisingthe at least partial conversion of the carbon dioxide into carbon monoxide and water; andthe at least partial conversion of the carbon monoxide into methane.

38. The method of claim 37, further comprising taking output fluids from the cell, and extracting at least part of the methane from the output fluids.

38. The method of claim 37 or claim 38, wherein the electrochemical cell also performs at least part of the at least partial conversion of the carbon dioxide into carbon monoxide and water.

40. The method of any one of claims 37 to 39, wherein a reverse water gas shift catalyst performs at least part of the at least partial conversion of the carbon dioxide into carbon monoxide and water.

41. The method of any one of claims 37 to claim 40, wherein the electrochemical cell is an electrolyser cell.

42. The method of claim 41, carried out using the electrolyser system of any one of claims 20 to 35, the electrolyser cell being the at least one electrolyser cell of the electrolyser of the electrolyser system.

43. The method of claim 41, the method being the methanation method of any one of claims 1 to 19, the electrolyser cell being the at least one electrolyser cell of the electrolyser of the electrolyser system.

44. A method for operating an electrolyser system, the electrolyser system comprising at least one electrochemical cell having a fuel inlet, a fuel outlet and a fuel fluid flow path connecting the fuel inlet and the fuel outlet, the method comprising;i) providing to the fuel inlet a fuel gas containing water and a source of carbon selected from one or more of CO and CO2;ii) operating the electrolyser system by applying a current to the at least one electrochemical cell;iii) at least partially electrolysing the steam into hydrogen and oxygen;iv) reacting the hydrogen with the source of carbon in the fuel fluid flow path to produce5 methane; andv) exhausting a product gas containing at least 5% methane by volume and one or more of H2, H2O, CO and CO2 from the fuel outlet.

45. The method of claim 44, carried out using the electrolyser system of any one of claims 20 to 31, the at least one electrochemical cell being the at least one electrolyser cell of the 10 electrolyser.

46. The method of claim 44, the method being the methanation method of any one of claims 1 to 19, the at least one electrochemical cell being the at least one electrolyser cell of the electrolyser.Application No: GB2311969.6Examiner:Raoul RutterClaims searched: 1-25Date of search: 29 January 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-25 WO2022 / 191069 Al (NGK INSULATORS LTD [IP]) See specifically figure 1 and abstract. X 1-25 US2023 / 160079 Al (OSAKA GAS CO LTD [JP]) See specifically abstract and figure 1. X 1-25 WO2023 / 127346 Al (HITACHI LTD [JP]) See specifically figures and embodiment 1. v A 1-25 US5362373 A (UNITED TECHNOLOGIES CORP [US]) See specifically figure 1 and abstract. X 1-25 WO2013 / 190581 Al (CAPRICCIOLI ANDREA [IT]) See specifically figure 2 and abstract. v A 1-25 WO2019 / 093518 Al (JAPAN AEROSPACE EXPLORATION [JP]) See specifically figures and abstract.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From C07C 0001 / 04 01 / 01 / 2006 BOID 0053 / 22 01 / 01 / 2006 C01B 0032 / 40 01 / 01 / 2017 C01B 0032 / 50 01 / 01 / 2017 C07C 0001 / 12 01 / 01 / 2006 C07C 0009 / 04 01 / 01 / 2006 C10L 0003 / 08 01 / 01 / 2006 C25B 0001 / 044 01 / 01 / 2021 C25B 0009 / 00 01 / 01 / 2021 C25B 0015 / 08 01 / 01 / 2006Application No: GB2311969.6Examiner:Raoul RutterClaims searched: 44-46Date of search: 21 August 2024Patents Act 1977Further Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance v A 44-46 US2023 / 160079 Al (OSAKA GAS CO LTD [JP]) See specifically example 3 on table 2, page 9. X 44-46 WO2023 / 127346 Al (HITACHI LTD [IP]) See specifically embodiment 1, paragraph [0050], X 44-46 US5362373 A (UNITED TECHNOLOGIES CORP [US]) See specifically example on column 6. X 44-46 WO2022 / 191069 Al (NGK INSULATORS LTD [JP]) See specifically figure 1 and abstract. X 44-46 WO2013 / 190581 Al (CAPRICCIOLI ANDREA [IT]) See specifically figure 2 and abstract. X 44-46 WO2019 / 093518 Al (JAPAN AEROSPACE EXPLORATION [JP]) See specifically figures and abstract.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From C07C 0001 / 04 01 / 01 / 2006 BOID 0053 / 22 01 / 01 / 2006 C01B 0032 / 40 01 / 01 / 2017 C01B 0032 / 50 01 / 01 / 2017 C07C 0001 / 12 01 / 01 / 2006 C07C 0009 / 04 01 / 01 / 2006 C10L 0003 / 08 01 / 01 / 2006 C25B 0001 / 044 01 / 01 / 2021 C25B 0009 / 00 01 / 01 / 2021 C25B 0015 / 08 01 / 01 / 2006

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