Gas Processing Device and Method

Abstract

A methane conversion device comprises a reaction chamber; a sensor for detecting the presence of methane; blowing means for directing external gasses Into the reaction chamber when the sensor detects the presence of methane above a predetermined threshold; conversion means that are configured to oxidise methane; and positioning means for positioning the device on an animal.

Claims

1. A methane conversion device comprising: a reaction chamber comprising conversion means that are configured to oxidise methane; a methane retention component; means for causing methane to be released from the methane retention component into the reaction chamber; a sensor that is adapted to detect the presence of methane within gas exterior to the methane conversion device; blowing means configured to drive gas from the exterior of the device onto the methane retention component when the sensor detects the presence of methane above a predetermined threshold; and positioning means for positioning the device on an animal.

2. A device according to claim 1, wherein the methane retention component comprises a chamber containing a porous material that is configured to reversibly absorb methane.

3. A device according to claim 2, wherein the porous material is provided by a zeolite mineral.

4. A device according to any one of the preceding claims, wherein a carbon dioxide filter is provided between the blowing means and the methane retention component, the carbon dioxide filter being configured to inhibit the passage of carbon dioxide to the methane retention component.

5. A device according to any one of the preceding claims, wherein the means for causing methane to be released from the methane retention component into the reaction chamber comprises a heating element.

6. A methane conversion device comprising: A reaction chamber; A sensor that is adapted to detect the presence of methane within gas exterior to the methane conversion device; Blowing means configured to drive gas from the exterior of the device towards the reaction chamber when the sensor detects the presence of methane above a predetermined threshold; Conversion means that are configured to oxidise methane; and Positioning means for positioning the device on an animal.

7. A methane conversion device according to any one of the preceding claims, wherein the blowing means are configured to drive gas towards the reaction chamber when the sensor detects the presence of methane above 100 ppm.

8. A methane conversion device according to any one of the preceding claims, wherein the reaction chamber has a volume less than 200 ml.

9. A methane conversion device according to any one of the preceding claims, wherein the conversion means comprises a heating element.

10. A methane conversion device according to claim 9, wherein the heating element comprised in the conversion means is a wire.

11. A methane conversion device according to claim 9 or claim 10, wherein the heating element comprised in the conversion means is a metallic resistance heating element.

12. A methane conversion device according to claim 11, wherein the metallic resistance heating element comprises principally nickel.

13. A methane conversion device according to claim 12, wherein the metallic heating element is a nichrome wire.

14. A methane conversion device according to any one of claims 9-13, wherein the heating element comprised in the conversion means is located within the reaction chamber.

15. A methane conversion device according claim 6, wherein the device comprises filtration means that are configured to inhibit the entry of one or more gaseous species other than methane into the reaction chamber.

16. A methane conversion device according to claim 6, wherein the device comprises trapping means that are configured to trap methane before it enters the reaction chamber.

17. A methane conversion device according to any one of claims 9-13, wherein the conversion means comprise additionally a catalyst, the catalyst being located within the reaction chamber.

18. A methane conversion device according to claim 17, wherein the catalyst comprises palladium.

19. A methane conversion device according to any one of the preceding claims, wherein the means for positioning the device on an animal comprise a nose ring.

20. A method of converting methane emitted from an animal into other chemical species, comprising the steps of providing a methane conversion device according to any one of the preceding claims and positioning the device on an animal.

Description

DETAILED DESCRIPTION

[0039] The invention will now be described by way of example with reference to the following Figures in which:

[0040] FIG. 1 shows a schematic front elevation view of a first embodiment of a methane conversion device according to a first aspect of the present invention;

[0041] FIG. 2 shows a schematic rear elevation view of the device of FIG. 1;

[0042] FIG. 3 shows a cross-sectional view of the device of FIG. 1;

[0043] FIG. 4 shows a cross-sectional view of a second embodiment of a methane conversion device according to the first aspect of the present invention.

[0044] Referring to FIGS. 1-3, a methane conversion device 10 comprises a housing 12 in which are provided a reaction chamber 14 and a battery compartment 16. The housing further comprises a methane sensor 18 disposed on the front side of the conversion device and blowing means 20 located adjacent the methane sensor 18 on the front side of the combustion device. Blowing means 20 are provided by an axial flow fan that is configured to drive gas from the exterior of the device towards reaction chamber 14.

[0045] Exhaust 22 is provided on the rear side of conversion device 10 and adapted to channel a gas stream from reaction chamber 14 towards the exterior of the device 10.

[0046] A palladium-containing catalytic bed is located within reaction chamber 14. The catalytic bed is in thermal contact with nichrome wire heating element 24

[0047] Opposed arms 28a,b are configured to retain the septum of the bovine therebetween. Tensioning bar 29 allows opposed arms 28a,b to be pulled closer together.

[0048] In use, opposed arms 28a,b are positioned on either side of the septum of the bovine and tensioning bar 29 is tightened so that opposed arms 28a,b retain the septum securely therebetween. Conversion device 10 is oriented such that the front side of the device faces the bovine's mouth. When the sensor 18 detects a methane concentration greater than e.g. 200 ppm, the blowing means 20 are activated to direct the exhaled gas from the bovine into reaction chamber 14. The catalyst in reaction chamber 14 is heated to a temperature of e.g. 600-700° C. by the nichrome wire heating element 24. The methane gas passing over the catalyst is oxidised to form principally water vapour and carbon dioxide, which are expelled from the device via exhaust 22.

[0049] Thus, the gas flow through the device follows the path denoted by arrow A-A.

[0050] An alternative embodiment of the combustion device is shown in FIG. 4 that has the same features as the embodiment of FIGS. 1-3, except that a filter 30 is provided between the blowing means 20 and the exhaust 32, instead of a catalyst. The filter 30 absorbs gasses such as carbon dioxide that are also present in the bovine exhalation, in order to increase the concentration of methane in the gas being transferred to the exhaust 32.

[0051] In this embodiment, the reaction chamber is provided within the exhaust 32. The reaction chamber comprises a nichrome wire heating element 34.

[0052] Other features of this alternative embodiment of the combustion device are the same as for the embodiment of FIGS. 1-3, and are denoted by like numerals.

[0053] In use, opposed arms 28a,b are positioned on either side of the septum of the bovine and tensioning bar 29 is tightened so that opposed arms 28a,b retain the septum securely therebetween. The combustion device 10′ is oriented such that the front side of the device faces the bovine's mouth. When the sensor 18 detects a methane concentration greater than e.g. 200 ppm, blowing means 20 are activated to direct the exhaled gas from the bovine through filter 30 and into exhaust 32.

[0054] Filter 30 extracts carbon dioxide from the gas stream, so as to increase the methane concentration to a level above the lower explosive limit of methane, which is approximately 4% by volume of air, depending on temperature and pressure. Once the gas stream enters exhaust 32 it passes over nichrome wire heating element 34, which is heated to a temperature of 700-800° C. The heating element 34 causes the methane in the gas stream to become oxidised to form principally carbon dioxide and water vapour, which are then expelled from the device via exhaust 32.

[0055] Thus, the gas flow through the device follows the path denoted by arrow B-B.

[0056] In a variant of the embodiment of FIG. 4, the filter 30 is provided by a chamber containing zeolite particles that are adapted to trap methane and carbon dioxide, while allowing nitrogen and oxygen to pass through into the reaction chamber 32. Once the zeolite particles reach saturation point (that is, they are not able to absorb any more carbon dioxide or methane), a filter heating element (not shown) is activated. This causes the trapped methane to be released into the reaction chamber 32 at a relatively high concentration, so that it may become oxidised as it passes over heated nichrome wire 34. This arrangement helps to ensure that the methane concentration in the reaction chamber 32 is above the lower explosive limit of the methane.

[0057] In a further modification of this variant, a further filter (not shown) is provided between blowing means 20 and the zeolite-containing chamber 30, the further filter being adapted to limit the amount of carbon dioxide arriving at the zeolite-containing chamber 30, so that the capacity of the zeolite particles to trap methane is increased.