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Title:
AN ATMOSPHERIC WATER GENERATOR AND CARBON DIOXIDE EXTRACTOR
Document Type and Number:
WIPO Patent Application WO/2022/061392
Kind Code:
A1
Abstract:
The present invention is directed to a renewable methane production assembly (10) comprising an atmospheric water capture generator (12) and an atmospheric carbon dioxide extractor (14). The production assembly (10) also comprises an electrolyser (16) effective in electrolysis of liquid water from the water capture generator (12), and a Sabatier reactor (18) for reacting hydrogen from the electrolyser (16) and CO2 from the carbon dioxide extractor (14) to produce renewable methane.

Inventors:
GILLESPIE ROHAN (AU)
Application Number:
PCT/AU2021/050780
Publication Date:
March 31, 2022
Filing Date:
July 20, 2021
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SOUTHERN GREEN GAS LTD (AU)
International Classes:
B01D53/26; B01J20/22; C07C1/12; C07C9/04; C25B1/04
Foreign References:
US9446365B22016-09-20
US10683644B22020-06-16
JP2009172479A2009-08-06
Attorney, Agent or Firm:
CLARK INTELLECTUAL PROPERTY PTY LTD (AU)
Download PDF:
Claims:
Claims

1 . An atmospheric water capture generator comprising: one or more flow passages for a heat exchange fluid which either (i) circulates through a cooling system associated with a Sabatier reactor, or (ii) is heated via an output stream of the Sabatier reactor to provide a relatively hot heat exchange fluid; an air-permeable substrate within which the one or more flow passages are integrated for effective heat exchange between the relatively hot heat exchange fluid contained in said flow passages and the air-permeable substrate, said substrate being coated with a water-adsorbent material for adsorbing liquid water from air passing through the air-permeable substrate to provide adsorbed liquid water which during the heat exchange between the heat exchange fluid and said substrate promotes desorption of the adsorbed water from said substrate in the generation of water from atmosphere.

2. An atmospheric water capture generator as claimed in claim 1 wherein the flow passages are each formed by respective flow tubes within which the heat exchange fluid is contained, said flow tubes being predominantly in contact with and surrounded by the air-permeable substrate.

3. An atmospheric water capture generator as claimed in claim 2 wherein the air- permeable substrate is shaped generally cylindrical and contained about its circumference with a canister wall.

4. An atmospheric water capture generator as claimed in any one of the preceding claims wherein the air-permeable substrate of the water capture generator is formed via additive manufacturing using a heat conductive metal or plastic providing the substrate with a relatively high surface area.

5. An atmospheric water capture generator as claimed in claim 4 wherein said substrate is formed with relatively high permeability wherein air passing through the substrate undergoes relatively low pressure drop.

6. An atmospheric water capture generator as claimed in either of claims 4 or 5 wherein said substrate is coated in the adsorbent material including a metal-organic framework (MOF), coordinated polymer, lithium aluminate or other inorganic compounds, or any derivatives thereof.

7. An atmospheric water capture generator as claimed in any one of claims 4 to 6 also comprising a first condensing heat exchanger configured to cool the desorbed water from an associated air stream saturated in the desorbed water thereby condensing and thus capturing said water from the atmosphere.

8. An atmospheric water capture generator as claimed in claim 7 wherein said first heat exchanger is formed integral with the remainder of the water capture generator as part of the additive manufacture.

9. An atmospheric water capture generator as claimed in either of claims 7 or 8 wherein the first heat exchanger includes one or more cooling tubes and associated fins or other heat exchange elements, said tube(s) designed to carry a relatively cool heat exchange fluid for exchanging heat with the saturated air stream to condense the desorbed water from said stream.

10. An atmospheric carbon dioxide extractor comprising: one or more flow passages for a heat exchange fluid which either (i) circulates through a cooling system associated with a Sabatier reactor, or (ii) is heated via an output stream of the Sabatier reactor to provide a relatively hot heat exchange fluid; an air-permeable substrate within which the one or more flow passages are integrated for effective heat exchange between the relatively hot heat exchange fluid contained in the flow passages and the air-permeable substrate, said substrate being coated with a C02-adsorbent material for extracting CO2 from air passing through the air-permeable substrate to provide adsorbed CO2 which during the heat exchange between the heat exchange fluid and said substrate promotes desorption of the adsorbed CO2 from said substrate in extracting CO2 from atmosphere.

11. An atmospheric carbon dioxide extractor as claimed in claim 10 wherein the flow passages are each formed by respective flow tubes within which the heat exchange fluid is contained, said flow tubes being predominantly in contact with and surrounded by the air-permeable substrate. 14

12. An atmospheric carbon dioxide extractor as claimed in claim 11 wherein the air-permeable substrate is shaped generally cylindrical and contained about its circumference with a canister wall.

13. An atmospheric carbon dioxide extractor as claimed in any one of claims 10 to 12 wherein the air-permeable substrate of the carbon dioxide extractor is formed via additive manufacturing using a heat conductive metal or plastic providing the substrate with a relatively high surface area.

14. An atmospheric carbon dioxide extractor as claimed in claim 13 wherein said substrate is formed with relatively high permeability wherein air passing through the substrate undergoes relatively low pressure drop.

15. An atmospheric carbon dioxide extractor as claimed in either of claims 13 or 14 wherein said substrate is coated in the adsorbent material including a metal-organic framework (MOF), coordinated polymer, lithium aluminate or other inorganic compounds, or any derivatives thereof.

16. A renewable methane production assembly comprising:

(1 ) an atmospheric water capture generator including: one or more flow passages for a heat exchange fluid which either (i) circulates through a cooling system, or (ii) is heated via an output stream to provide a relatively hot heat exchange fluid, an air-permeable substrate within which the one or more flow passages are integrated for effective heat exchange between the relatively hot heat exchange fluid contained in the flow passages and the air-permeable substrate, said substrate being coated with a water-adsorbent material for adsorbing liquid water from air passing through the air-permeable substrate to provide adsorbed liquid water which during the heat exchange between the heat exchange fluid and said substrate promotes desorption of the adsorbed liquid water from said substrate in the capture of water from atmosphere; 15

(2) an electrolyser operatively coupled to the water capture generator for receiving the water captured from atmosphere, the electrolyser being effective in electrolysis of the liquid water to produce hydrogen;

(3) an atmospheric carbon dioxide extractor including: one or more other flow passages for another heat exchange fluid which either (i) circulates through the cooling system, or (ii) is heated via an output stream to provide another relatively hot heat exchange fluid, another air-permeable substrate within which the one or more other flow passages are integrated for effective heat exchange between the other relatively hot heat exchange fluid contained in the other flow passages and the other air-permeable substrate, said other substrate being coated with a CO2- adsorbent material for adsorbing CO2 from air passing through the other permeable substrate to provide adsorbed CO2 which during the heat exchange between the other heat exchange fluid and said other substrate promotes desorption of the adsorbed CO2 from said other substrate in the extraction of CO2 from atmosphere;

(4) a Sabatier reactor operatively coupled to the electrolyser and the carbon dioxide extractor for receiving the hydrogen and the CO2, respectively, which react to produce renewable methane.

17. A renewable methane production assembly as claimed in claim 16 wherein the atmospheric water capture generator also includes a first condensing heat exchanger configured to cool the desorbed water from an associated air stream saturated in the desorbed water thereby condensing and thus capturing said water from the atmosphere.

18. A renewable methane production assembly as claimed in claim 17 wherein said first heat exchanger is formed integral with the remainder of the water capture generator as part of the additive manufacture.

19. A renewable methane production assembly as claimed in claim 18 wherein the first heat exchanger includes one or more cooling tubes and associated fins or other heat exchange elements, said tube(s) designed to carry a relatively cool heat 16 exchange fluid for exchanging heat with the saturated air stream to condense the desorbed water from said stream.

20. A renewable methane production assembly as claimed in any one of claims 16 to 19 also comprising a second condensing heat exchanger associated with the Sabatier reactor whereby the output stream of said reactor exchanges heat with the heat exchange fluid in the condensing heat exchanger to desorb water from the gas stream and to provide the relatively hot heat exchange fluid for use in the desorption of the adsorbed water or CO2 from the adsorbent material of the air-permeable substrate.

21 . A renewable methane production assembly as claimed in claim 20 further comprising a heat exchange fluid tank associated with either or both of the water capture generator and the carbon dioxide extractor, said tank located downstream of said generator and/or extractor for supplying the heat exchange fluid to the cooling system of the Sabatier reactor or the second condensing heat exchanger, respectively.

22. A renewable methane production assembly as claimed in either of claims 20 or 21 wherein the second heat exchanger is associated with the electrolyser wherein water produced in the Sabatier reaction and condensed in the second heat exchanger is provided as the water for electrolysis.

23. A renewable methane production assembly as claimed in any one of claims 20 to 22 wherein the first or second condensing heat exchangers are formed via additive manufacturing using a heat conductive metal or plastic providing the cooling tube(s) and associated heat exchange elements with a relatively high surface area.

24. A renewable methane production assembly as claimed in any one of claims 20 to 23 also comprising recirculation circuits associated with respective of the water capture generator and the carbon dioxide extractor for recirculating the heat exchange fluid between the generator/extractor and the cooling system/condensing heat exchanger associated with the Sabatier reactor. 17

25. A renewable methane production assembly as claimed in claim 24 wherein the recirculation circuits each include recirculation pumps associated with respective of the water capture generator and the carbon dioxide extractor for circulating the heat exchange fluid.

26. A renewable methane production assembly as claimed in any one of claims 16 to 25 wherein the heat exchange fluid is water, a mixture of water and glycol, or an oil-based heat transfer liquid.

27. A renewable methane production assembly as claimed in any one of claims 16 to 26 further comprising a solar heating unit arranged for supplementary heating of the heat exchange fluid to assist with desorption of the adsorbed water or CO2 from the corresponding substrate.

28. A renewable methane production assembly as claimed in claim 27 wherein the solar heating unit includes an evacuated tube collector or solar panel heater through which the heat exchange fluid circulates.

29. A Sabatier reactor comprising: one or more flow passages for a cooling fluid which maintains reaction temperatures for an exothermic reaction associated with the Sabatier reactor at or below a threshold temperature; a permeable substrate within which said flow passages are integrated for effective heat exchange between said cooling fluid contained in the flow passages and the permeable substrate, said substrate being at least in part coated with a catalyst which promotes the Sabatier reaction wherein the hydrogen and carbon dioxide reactants enter the substrate and are exposed to the catalyst in the production of renewable methane.

30. A Sabatier reactor as claimed in claim 29 wherein the flow passages are each formed by respective flow tubes within which the cooling fluid is contained, said flow tubes being at least in part coated in the catalyst and otherwise predominantly in contact and surrounded by the permeable substrate. 18

31 . A Sabatier reactor as claimed in claim 30 wherein the permeable substrate is substantially contained by a reactor chamber.

32. A Sabatier reactor as claimed in any one of claims 29 to 31 wherein the permeable substrate is formed as a mesh or web of relatively fine wires or filaments via additive manufacturing providing the substrate with a relatively high surface area.

33. A Sabatier reactor as claimed in claim 32 wherein said substrate is formed with relatively high permeability wherein the reactants and products passing through the substrate undergo relatively low pressure drop.

34. A Sabatier reactor as claimed in either of claims 32 or 33 wherein said substrate is also coated in the catalyst.

Description:
AN ATMOSPHERIC WATER GENERATOR AND CARBON DIOXIDE EXTRACTOR

Technical Field

[0001] The present invention is broadly directed to either an atmospheric water capture generator or an atmospheric carbon dioxide extractor. The invention also relates to a renewable methane production assembly including a water capture generator and a carbon dioxide extractor both associated with a methanation reactor, in particular a Sabatier reactor.

Background

[0002] The applicant in their International patent publication No. WO 2020/000020 describes a renewable methane production system including a water capture module for directly capturing water from air to provide water in a liquid form. The captured water is electrolysed to produce hydrogen which is reacted with carbon dioxide in a Sabatier reactor to produce renewable methane. The water capture module includes an absorbent unit having a metal-organic framework (MOF) designed to absorb water from the air. The water capture module is associated with a heating unit separate from the absorbent unit and designed to heat the MOF to release the absorbed water. The heating unit disclosed in WO 2020/000020 includes either a solar heating unit or a heat recovery unit associated with the Sabatier reactor and designed to recovery waste heat from the exothermic reaction associated with said reactor.

[0003] It is to be understood that any acknowledgement of prior art in this patent specification is not to be taken as an admission that this prior art forms part of the general knowledge in the relevant field in Australia or elsewhere.

Summary of Invention

[0004] According to a first aspect of the present invention there is provided an atmospheric water capture generator comprising: one or more flow passages for a heat exchange fluid which either (i) circulates through a cooling system associated with a Sabatier reactor, or (ii) is heated via an output stream of the Sabatier reactor to provide a relatively hot heat exchange fluid; an air-permeable substrate within which the one or more flow passages are integrated for effective heat exchange between the relatively hot heat exchange fluid contained in said flow passages and the air-permeable substrate, said substrate being coated with a water-adsorbent material for adsorbing liquid water from air passing through the air-permeable substrate to provide adsorbed liquid water which during the heat exchange between the heat exchange fluid and said substrate promotes desorption of the adsorbed water from said substrate in the generation of water from atmosphere.

[0005] According to a second aspect of the invention there is provided an atmospheric carbon dioxide extractor comprising: one or more flow passages for a heat exchange fluid which either (i) circulates through a cooling system associated with a Sabatier reactor, or (ii) is heated via an output stream of the Sabatier reactor to provide a relatively hot heat exchange fluid; an air-permeable substrate within which the one or more flow passages are integrated for effective heat exchange between the relatively hot heat exchange fluid contained in the flow passages and the air-permeable substrate, said substrate being coated with a C02-adsorbent material for extracting CO2 from air passing through the air-permeable substrate to provide adsorbed CO2 which during the heat exchange between the heat exchange fluid and said substrate promotes desorption of the adsorbed CO2 from said substrate in extracting CO2 from atmosphere.

[0006] According to a third aspect of the invention there is provided a renewable methane production assembly comprising:

(1 ) an atmospheric water capture generator including: one or more flow passages for a heat exchange fluid which either (i) circulates through a cooling system, or (ii) is heated via an output stream to provide a relatively hot heat exchange fluid, an air-permeable substrate within which the one or more flow passages are integrated for effective heat exchange between the relatively hot heat exchange fluid contained in the flow passages and the air- permeable substrate, said substrate being coated with a water-adsorbent material for adsorbing liquid water from air passing through the air- permeable substrate to provide adsorbed liquid water which during the heat exchange between the heat exchange fluid and said substrate promotes desorption of the adsorbed liquid water from said substrate in the capture of water from atmosphere;

(2) an electrolyser operatively coupled to the water capture generator for receiving the water captured from atmosphere, the electrolyser being effective in electrolysis of the liquid water to produce hydrogen;

(3) an atmospheric carbon dioxide extractor including: one or more other flow passages for another heat exchange fluid which either (i) circulates through the cooling system, or (ii) is heated via an output stream to provide another relatively hot heat exchange fluid, another air-permeable substrate within which the one or more other flow passages are integrated for effective heat exchange between the other relatively hot heat exchange fluid contained in the other flow passages and the other air-permeable substrate, said other substrate being coated with a C02-adsorbent material for adsorbing CO2 from air passing through the other permeable substrate to provide adsorbed CO2 which during the heat exchange between the other heat exchange fluid and said other substrate promotes desorption of the adsorbed CO2 from said other substrate in the extraction of CO2 from atmosphere;

(4) a Sabatier reactor operatively coupled to the electrolyser and the carbon dioxide extractor for receiving the hydrogen and the CO2, respectively, which react to produce renewable methane.

[0007] Preferably the flow passages are each formed by respective flow tubes within which the heat exchange fluid is contained, said flow tubes being predominantly in contact with and surrounded by the air-permeable substrate. More preferably the air-permeable substrate is shaped generally cylindrical and contained about its circumference with a canister wall.

[0008] Preferably the air-permeable substrate of either the water capture generator or the carbon dioxide extractor is formed via additive manufacturing using a heat conductive metal or plastic providing the substrate with a relatively high surface area. More preferably said substrate is formed with relatively high permeability wherein air passing through the substrate undergoes relatively low pressure drop. Even more preferably said substrate is coated in the adsorbent material including a metal-organic framework (MOF), coordinated polymer, lithium aluminate or other inorganic compounds, or any derivatives thereof.

[0009] Preferably the atmospheric water capture generator also includes a first condensing heat exchanger configured to cool the desorbed water from an associated air stream saturated in the desorbed water thereby condensing and thus capturing said water from the atmosphere. More preferably said first heat exchanger is formed integral with the remainder of the water capture generator as part of the additive manufacture. Even more preferably the first heat exchanger includes one or more cooling tubes and associated fins or other heat exchange elements, said tube(s) designed to carry a relatively cool heat exchange fluid for exchanging heat with the saturated air stream to condense the desorbed water from said stream.

[0010] Preferably the production assembly also comprises a second condensing heat exchanger associated with the Sabatier reactor whereby the output stream of said reactor exchanges heat with the heat exchange fluid in the condensing heat exchanger to desorb water from the gas stream and to provide the relatively hot heat exchange fluid for use in the desorption of the adsorbed water or CO2 from the adsorbent material of the air-permeable substrate. More preferably the production assembly further comprises a heat exchange fluid tank associated with either or both of the water capture generator and the carbon dioxide extractor, said tank located downstream of said generator and/or extractor for supplying the heat exchange fluid to the cooling system of the Sabatier reactor or the second condensing heat exchanger, respectively. Even more preferably the second heat exchanger is associated with the electrolyser wherein water produced in the Sabatier reaction and condensed in the second heat exchanger is provided as the water for electrolysis.

[0011 ] Preferably the first or second condensing heat exchangers are formed via additive manufacturing using a heat conductive metal or plastic providing the cooling tube(s) and associated heat exchange elements with a relatively high surface area. [0012] Preferably the production assembly also comprises recirculation circuits associated with respective of the water capture generator and the carbon dioxide extractor for recirculating the heat exchange fluid between the generator/extractor and the cooling system/condensing heat exchanger associated with the Sabatier reactor. More preferably the recirculation circuits each include recirculation pumps associated with respective of the water capture generator and the carbon dioxide extractor for circulating the heat exchange fluid. Even more preferably the heat exchange fluid is water, a mixture of water and glycol, or an oil-based heat transfer liquid.

[0013] Preferably the production assembly further comprises a solar heating unit arranged for supplementary heating of the heat exchange fluid to assist with desorption of the adsorbed water or CO2 from the corresponding substrate. More preferably the solar heating unit includes an evacuated tube collector or solar panel heater through which the heat exchange fluid circulates.

[0014] According to a fourth aspect of the invention there is provided a Sabatier reactor comprising: one or more flow passages for a cooling fluid which maintains reaction temperatures for an exothermic reaction associated with the Sabatier reactor at or below a threshold temperature; a permeable substrate within which said flow passages are integrated for effective heat exchange between said cooling fluid contained in the flow passages and the permeable substrate, said substrate being at least in part coated with a catalyst which promotes the Sabatier reaction wherein the hydrogen and carbon dioxide reactants enter the substrate and are exposed to the catalyst in the production of renewable methane.

[0015] Preferably the flow passages are each formed by respective flow tubes within which the cooling fluid is contained, said flow tubes being at least in part coated in the catalyst and otherwise predominantly in contact and surrounded by the permeable substrate. More preferably the permeable substrate is substantially contained by a reactor chamber.

[0016] Preferably the permeable substrate is formed as a mesh or web of relatively fine wires or filaments via additive manufacturing providing the substrate with a relatively high surface area. More preferably said substrate is formed with relatively high permeability wherein the reactants and products passing through the substrate undergo relatively low pressure drop. Even more preferably said substrate is also coated in the catalyst.

Brief Description of Drawings

[0017] In order to achieve a better understanding of the nature of the present invention a preferred embodiment of an atmospheric water capture generator or an atmospheric carbon dioxide extractor together with related aspects of the technology will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic flow diagram of a renewable methane production assembly including both an atmospheric water capture generator and an atmospheric carbon dioxide extractor of a preferred embodiment of the various aspects of the invention;

Figure 2 illustrates either the water capture generator or the carbon dioxide extractor taken from the renewable methane production assembly of the preferred embodiment of figure 1 .

Detailed Description

[0018] As seen in figure 1 , there is a renewable methane production assembly 10 broadly comprising an atmospheric water capture generator 12 and an atmospheric carbon dioxide extractor 14. The water capture generator 12 is a preferred embodiment of the first aspect of the invention, and the carbon dioxide extractor 14 is a preferred embodiment of the second aspect of the invention. The renewable methane production assembly 10 is a preferred embodiment of the third aspect of the invention and also comprises an electrolyser 16 effective in electrolysis of liquid water from the water capture generator 12, and a Sabatier reactor 18 for reacting hydrogen from the electrolyser 16 and CO2 from the carbon dioxide extractor 14 to produce renewable methane. [0019] As seen in figure 2, the water capture generator 12 or the carbon dioxide extractor 14 of the preferred embodiment are of substantially the same construction. In this representative embodiment, the water capture generator 12 comprises:

1 . one or more flow passages 20 for a heat exchange fluid 21 which either (a) circulates through a cooling system (not shown) associated with the Sabatier reactor 18, or (b) is heated via an output stream of the Sabatier reactor 18 to provide a relatively hot heat exchange fluid;

2. an air-permeable substrate 22 within which said flow passages 20 are integrated for effective heat exchange between the relatively hot heat exchange fluid 21 contained in said passages 20 and the air-permeable substrate 22, said substrate 22 being coated with a water-adsorbent material (not shown) for adsorbing liquid water from air 23 passing through the air- permeable substrate 22 to provide adsorbed liquid water which during the heat exchange between the heat exchange fluid 21 and said substrate 22 promotes desorption of the adsorbed water from said substrate 22 in the generation of water from atmosphere.

[0020] In this embodiment, said one or more flow passages are in the form of a single helically-coiled tube 20 containing a flow of the relatively hot heat exchange fluid 21 . The single flow tube 20 being integrated within the air-permeable substrate 22 is as such embedded within and surrounded by the substrate 22. In this example, the air-permeable substrate 22 is shaped generally cylindrical and contained about its circumference with a canister wall 24. The air-permeable substrate 22 is exposed to atmosphere at each of its opposing ends permitting the flow of air 23 through said substrate 22 for water adsorption.

[0021 ] It will be understood that the carbon dioxide extractor 14 is of similar construction and operation to the water capture generator 12 except its air-permeable substrate 22 is coated with a CO2 adsorbent material for extracting CO2 from the through flow of air 23. In this case, the adsorbed CO2 is desorbed from the CO2- asorbent material which is heated via the relatively hot heat exchange fluid or water/glycol mixture 21 . [0022] In this embodiment, the water capture generator 12 incorporates a first condensing heat exchanger 25 configured to cool the desorbed water from an associated air stream saturated in the desorbed water thereby condensing said water. In this example the first heat exchanger 25 is formed integral with the remainder of the water capture generator 12. The first heat exchanger 25 includes one or more cooling tubes and associated fins or other heat exchange elements (not shown). The cooling tube(s) are designed to carry a relatively cool heat exchange fluid for exchanging heat with the saturated air stream to condense the desorbed water from said stream.

[0023] In this embodiment and as best seen in figure 1 , the water capture generator 12 recovers heat from both the Sabatier reactor 18 and a second condensing heat exchanger 26 connected to an output stream of the reactor 18. For this purpose each of the water capture generator 12 and the carbon dioxide extractor 14 may include separate flow passages or water/glycol tubes. In the exemplary construction of figure 2, the water/glycol flow tubes may be a pair of said tubes arranged coaxially inside one another. For simplicity and clarity, the water capture generator 12 of figure 2 is shown with the single water/glycol tube 20.

[0024] In this embodiment, the air-permeable substrate 22 is formed via additive manufacturing using a lightweight and heat conductive metal. This additive manufacturing typically involves 3D printing providing the substrate 22 with both a relatively high surface area and relatively high permeability wherein air passing through the substrate 22 undergoes relatively low pressure drop. It will be understood that the printed substrate 22 is coated in an adsorbent material including a metalorganic framework (MOF) of a predetermined composition depending on its requirement to adsorb either water or CO2. The adsorbent material also extends to coordinated polymers, lithium aluminate or other inorganic compounds, or any derivatives thereof.

[0025] It is to be understood that the first or second condensing heat exchangers 25/26 may also be formed via additive manufacturing using a heat conductive metal or plastic. This arrangement provides the cooling tube(s) and associated heat exchange elements with a relatively high surface area. [0026] Returning to figure 1 , the production assembly 10 of this example further comprises a heat exchange fluid tank 28 associated with both the water capture generator 12 and the carbon dioxide extractor 14. This tank 28 is in the form of a water/glycol tank located downstream of said generator 12 and said extractor 14 for supplying the heat exchange fluid to the cooling system of the Sabatier reactor 18 or the second condensing heat exchanger 26. Otherwise, the renewable methane production assembly 10 of this embodiment also comprises:

1 . water/glycol or other heat exchange fluid recirculation circuits 30 and 32 for the water capture generator 12 and associated with respective of the Sabatier reactor 18 and the second condensing heat exchanger 26;

2. water/glycol recirculation circuits 34 and 36 for the carbon dioxide extractor and dedicated to respective of the Sabatier reactor 18 and the second condensing heat exchanger 26.

Although not illustrated, it will be understood that each of the recirculation circuits such as 30 includes a recirculation pump associated with the water capture generator 12 for circulating the water/glycol mixture or other heat exchange fluid in this case between the Sabatier reactor 18 and the water capture generator 12.

[0027] Although not illustrated, the renewable methane production assembly 10 may further comprise a solar heating unit arranged for supplementary heating of the heat exchange fluid with respective of the water capture generator 12 or the carbon dioxide extractor 14. It will be understood that the solar heating unit assists with desorption of the adsorbed water or CO2 from the corresponding substrate such as 22 where insufficient heating is available or provided by either the Sabatier reactor 18 and/or the second condensing heat exchanger 26. In this addition or variation, the solar heating unit may include an evacuated tube collector or solar panel heater through which the water/glycol mixture or other heat exchange fluid circulates.

[0028] In a fourth aspect of the technology (not specifically illustrated) there is provided a Sabatier reactor of similar construction to the water capture generator 12 or carbon dioxide extractor 14 of the embodiment of figure 2. The Sabatier reactor of this embodiment comprises 1 . one or more flow passages for a cooling fluid which maintains reaction temperatures for an exothermic reaction associated with the Sabatier reactor at or below a threshold temperature;

2. a permeable substrate in heat conductive communication with said heat exchange fluid contained in the flow passages, said substrate at least in part coated with a catalyst which promotes the Sabatier reaction wherein the hydrogen and carbon dioxide reactants enter the substrate and are exposed to the catalyst in the production of renewable methane.

[0029] The one or more flow passages are in the form of flow tubes integrated within the permeable substrate. In this example the cooling fluid is contained within the flow tubes which are at least in part coated in the catalyst and otherwise predominantly surrounded by the permeable substrate.

[0030] In this embodiment, the permeable substrate is formed as a mesh or web of relatively fine wires or filaments via additive manufacturing providing the substrate with a relatively high surface area. The permeable substrate which in this case is coated in the catalyst is formed with relatively high permeability wherein the reactants and products passing through the substrate undergo relatively low pressure drop.

[0031 ] Now that a preferred embodiment of the various aspects of the technology have been described it will be apparent to those skilled in the art that they have at least the following advantages:

1 . the flow passages of the generator or extractor are integrated within the air- permeable substrate for effective heat exchange in desorption of adsorbed water and/or carbon dioxide;

2. the integrated form of the generator/extractor lends itself to additive manufacturing;

3. the renewable methane production assembly and the related technologies are “powered” solely by renewable energy sources;

4. the production assembly and its associated water capture generator and carbon dioxide extractor recover waste heat from the Sabatier reactor in promoting desorption of water and CO2; 5. the water capture generator or carbon dioxide extractor are effective in adsorption of either water or CO2 directly from air in providing water as a hydrogen source and CO2 as feedstocks for the Sabatier reaction in the production of renewable methane.

[0032] Those skilled in the art will appreciate that the invention as described herein is susceptible to variations and modifications other than those specifically described. For example, the renewable methane production assembly may include either of the water capture generator or the carbon dioxide extractor, rather than both aspects of the technology, and still remain within the scope of this application.

Furthermore, the heat recovery provided it is generally associated with the Sabatier reaction need not extend to both the cooling system of the Sabatier reactor and the condensing heat exchanger. The construction of the water capture generator or the carbon dioxide extractor may vary from the preferred embodiment provided it promotes desorption of the adsorbed water or CO2 utilising a heat exchange fluid associated with a Sabatier reactor and contained within one or more flow passages arranged to effectively exchange heat with an integrated air-permeable substrate coated with either a water or CO2 adsorbent material. It is to be understood that the heat exchange fluid associated with the Sabatier reactor is not to be limited to water or water/glycol but considering the relatively high reaction temperatures involved may also extend to an oil-based heat transfer fluid.

[0033] All such variations and modification are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.