PRIORITY DOCUMENT

[0001] The present application claims priority from Australian Provisional Patent Application No. 2022903266 titled “CONTROL OF METHANE DISCHARGE” and filed on 2 November 2022, the content of which is hereby incorporated by reference in its entirety.

INCORPORATION BY REFERENCE

[0002] The following publications are referred to in the present application and their contents are hereby incorporated by reference in their entirety:

• United States Patent No. 7,326,329;

• Australian Patent 2008209322;

• United Kingdom Patent GB2460000;

• Chinese Patent ZL200880012716;

• South African Patent 2011/04916;

• Hong Kong Patent HK1137408; and

• United States Patent 10,316,416.

TECHNICAL FIELD

[0003] The present disclosure relates to methane sequestration.

BACKGROUND

[0004] Methane is about 25 times more potent as a greenhouse gas than carbon dioxide. Methane is produced in many ways in modern society. For example, methane is discharged from farm animals such as cattle, sheep and pigs as shown in Figure 1. The amount of methane produced by farm animals per animal per year is 120kg for western cattle, 60kg for non-western cattle, 8kg for sheep and 1.5kg for pigs (Source: NASA Goddard Institute for Space Science). For cattle and sheep alone, this amounts to 188.8 billion tonnes per year of methane produced. Converted to a carbon dioxide equivalent, this is equivalent to 4,720 billion tonnes of carbon dioxide.

[0005] Another source of methane discharge to the atmosphere is coal mining. Coal deposits contain methane and as the coal is mined, methane is released and is collected in the mine ventilation system. Unfortunately, the air in the mine ventilation system is discharged to the atmosphere along with the methane.

[0006] There is a need to provide systems, apparatus and processes for controlling the discharge of methane from activities such as farming and mining.

SUMMARY

[0007] Aspects of the present disclosure are predicated, at least in part, on the inventor’s view that a parasite in the rumen of cattle consumes about 18% of the nutrient intake of the cattle and converts this to methane. As a result, the inventor developed a system whereby activated water produced in a unipolar electrolysis apparatus is ingested by cattle and it will neutralise the parasite and 18% of nutrient intake will then be converted to weight gain instead of methane.

[0008] Thus, according to a first aspect, there is provided an animal watering system comprising an activated water source and an animal watering station configured to receive activated water from the activated water source, wherein the activated water source comprises a unipolar electrolytic cell configured to produce activated water containing a desired amount of hydrogen peroxide.

[0009] According to a second aspect, there is a provided a process for reducing methane emissions from animals, the process comprising producing activate water containing a desired amount of hydrogen peroxide using a unipolar electrolytic cell and providing the activated water to animals for consumption.

[0010] Other aspects of the present disclosure are predicated on the inventor’s discovery that methane can be converted to carbon dioxide and hydrogen gas by contacting it with a composition comprising activated water formed using a unipolar electrolytic cell and Fe ²⁺ ions.

[0011] Thus, according to a third aspect, there is provided a methane conversion system comprising an activated water source and a mixer for contacting activated water from the activated water source with a gas containing methane and with a source of Fe ²⁺ ions, wherein the activated water source comprises a unipolar electrolytic cell configured to produce activated water and the activated water, the gas containing methane and the Fe ²⁺ ions are contacted in the mixer under conditions to produce carbon dioxide and hydrogen gas from the methane and water.

[0012] According to a fourth aspect, there is provided a process for sequestering methane, the process comprising contacting a gas containing methane with a source of Fe ²⁺ ions and activated water produced using a unipolar electrolytic cell under conditions to produce carbon dioxide and hydrogen gas from the methane and water. BRIEF DESCRIPTION OF THE FIGURES

[0013] Embodiments of the present disclosure will be discussed with reference to the accompanying figures wherein:

[0014] Figure 1 is a schematic illustration showing how methane is produced in farm animals;

[0015] Figure 2 is a schematic diagram showing unipolar electrolytic cell for producing activated water;

[0016] Figure 3 is a schematic diagram of an embodiment of the present disclosure showing an animal watering system comprising a unipolar electrolytic cell configured to produce activated drinking water for farm animals;

[0017] Figure 4 is a schematic diagram of an apparatus for determining methane production from a cohort of animals provided with ordinary water for drinking and a cohort of animals provided with activated water for drinking; and

[0018] Figure 5 is a schematic diagram of an embodiment of the present disclosure showing an apparatus for sequestration of methane from a coal mine.

DESCRIPTION OF EMBODIMENTS

[0019] Referring to Figures 2 and 3, an embodiment of an animal watering system 10 is shown. The animal watering system 10 comprises an activated water source 12 and an animal watering station 14. The animal watering station 14 is configured to receive activated water 16 from the activated water source 12. The activated water source 12 comprises a unipolar electrolytic cell 18 configured to produce activated water containing a desired amount of hydrogen peroxide.

[0020] The term “unipolar electrolytic cell” and related terms used herein means a diaphragm-less electrolytic cell having an anode cell and a cathode cell connected by a DC power source and an external conductor, such as is disclosed in United States Patent No. 7,326,329. Unipolar electrolysis of water may also refer to diaphragm type unipolar electrolysis described in United States Patent No. 10,316,416.

[0021] The present applicant has previously developed a unipolar water disinfection technology shown in Figure 2 (see also United States Patent No. 7,326,329). Briefly, the unipolar electrolytic cell comprises an anode cell 50 and a cathode cell 52. The anode cell 50 comprises an anode electrode 54 and an anode cell solution electrode 56. The cathode cell 52 comprises a cathode electrode 58 and a cathode cell solution electrode 60. A direct electric current is applied to the anode electrode 54 and cathode solution electrode 60. The direct electric current is usually a steady current, but in some embodiments a pulsed direct current is applied to the anode electrode 54 and the cathode solution electrode 60. The frequency may range up to several thousand cycles per second and the amplitude may range up to 100 times the average of the direct current. The objective of the pulsed current is to achieve the desire result at a lower energy cost.

[0022] Large surface area contact between the electrodes and the electrolyte can be achieved by the construction of the electrode such as a gauze or expanded metal construction where the electrolyte is passed through the electrode.

[0023] In the unipolar electrolytic treatment of water, various active species including CLO, HC1O, Cl, CIO2, CIO, OH, O, HO2, H2O2, O3, S2O8 and C2O6 may be produced. In the system and process disclosed herein, the unipolar process is modified to produce more hydrogen peroxide in small but powerful quantities. Hydrogen peroxide is a biocide that will neutralise the parasite producing the methane.

[0024] The present inventor has surprisingly discovered that when a pulsed current is applied to the unipolar electrolytic cell 18 the amounts of hydrogen peroxide produced in the cell can be increased. More specifically, the present inventor found that the production of hydrogen peroxide is increased proportionately with an increased pulse rate. For example, when the pulse rate is about 80 kilohertz an adequate amount of hydrogen peroxide is produced by the unipolar electrolytic cell 18. The pulsed current may have a frequency of from about 50 kilohertz to about 100 kilohertz, such as about 50 kilohertz or about 80 kilohertz.

[0025] In some embodiments, the amount of hydrogen peroxide produced in the unipolar electrolytic cell is from about lOppm to about 50ppm, such as about lOppm, about 15ppm, about 20ppm, about 25ppm, about 30ppm, about 35ppm, about 40ppm, about 45ppm or about 50ppm. Thus, in certain embodiments, the activated water comprises from about lOppm to about 50ppm hydrogen peroxide. In certain embodiments, the unipolar electrolytic cell 18 is operated at 50 kilohertz and about 15 ppm hydrogen peroxide is produced. In practice, it is found that even relatively small amounts of hydrogen peroxide produced are very active.

[0026] The unipolar electrolytic cell 18 is powered by an electric power source 20. The power source

20 may be mains power or it may be one or more renewable energy sources. The term “renewable energy” used herein refers to, but is not limited to, solar energy, wind energy and wave energy. As discussed in detail later, the energy storage system 10 can also be used in conjunction with other power plants to allow a more efficient operation of a plant. When electric power comes from solar or wind energy the animal watering system 10 is relatively simple to install and operation even in remote locations. The power source can also be intermittent without adversely affecting the operation of the system.

[0027] In the embodiment illustrated in Figure 3, the animal watering system 10 further comprises a mixing tank 30. The mixing tank 30 is used to mix water that is to be treated in the unipolar electrolytic cell 18 with any additives required to provide pre-treated water 32. Additives may be any additives used for farm animal drinking water, including minerals, vitamins, therapeutics, insecticides, etc. The pretreated water 32 can be transferred to the unipolar electrolytic cell 18 using a suitable pump 34 at any suitable time or as desired.

[0028] Activated water 16 produced in the unipolar electrolytic cell 18 is transferred to a storage tank 36. The storage tank 36 is partitioned into a fresh water section 38 and an activated water section 40. Fresh water in the fresh water section 38 of the storage tank 36 is used to supply fresh water to the unipolar electrolytic cell 18 by pump 34. In an alternative that is not illustrated, the storage tank 36 may comprise separate fresh water tank and activated water tanks.

[0029] Farm animals drink water for their health. The activated water 16 can be supplied as their drinking water to a drinking trough 40. The drinking trough has a float valve 42 to maintain the water level in the trough 40. Troughs and other apparatus for watering animals are known and any suitable trough or other apparatus can be used.

[0030] The effectiveness of the activated water on reducing methane discharge from farm animals can be tested using a system as shown in Figure 4. The system consists of two air-tight sheds where outlet air is monitored by a flow meter and a sample taken and the methane analysed by gas chromatography. Cattle are weighed at the start of the test. Activated water is fed to cattle in one shed while ordinary water is fed to cattle in the other shed. The sheds are washed regularly to ensure the cattle waste does not affect the methane reading. The test may last for several weeks. At the end of the test, the cattle are weighed, and the results analysed to determine the effectiveness of the Unipolar water in reducing the methane discharge and the weight of the cattle.

[0031] Referring to Figure 5, there is shown a methane conversion system 100. The methane conversion system 100 comprises an activated water source 102 and a mixer 104 for contacting activated water 106 from the activated water source 102 with a gas 108 containing methane and with a source of Fe ²⁺ ions 110. The activated water source 102 comprises a unipolar electrolytic cell 112 configured to produce activated water 106. The activated water 106, the gas 108 containing methane and the Fe ²⁺ ions 110 are contacted in the mixer 104 under conditions to produce carbon dioxide and hydrogen gas from the methane and water. [0032] Also disclosed herein is a process for sequestering methane. The process comprises contacting a gas containing methane with a source of Fe ²⁺ ions and activated water produced using a unipolar electrolytic cell under conditions to produce carbon dioxide and hydrogen gas from the methane and water.

[0033] In the embodiment illustrated in Figure 5, the mixer 104 comprises a venturi 114 and an absorption tower 116. The venturi 114 and the absorption tower 116 are connected in series with the absorption tower 116 downstream from the venturi 114.

[0034] Gas 108 containing methane from the ventilation system of a coal mine is passed into the venturi 114 for the efficient mixing of the gas 108 with the activated water 106. The gas 108 is then given a second contact with activated water 106 in absorption tower 116. The activated water reacts with methane to form hydrogen ions and carbon dioxide in the reaction:

CH ₄ + 2H ₂ O CO ₂ + 4H ₂

[0035] The process is catalysed by Fe ions.

[0036] In an open pit coal mine, deep holes are sunk and then vacuumed to extract methane and then the methane is treated the same way, as shown in Figure 5.

[0037] The present invention will reduce the methane gas pollution from farm animals and from operating coal mines.

[0038] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.

[0039] It will be understood that the terms “comprise” and “include” and any of their derivatives (e.g. comprises, comprising, includes, including) as used in this specification, and the claims that follow, is to be taken to be inclusive of features to which the term refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied.

[0040] In some cases, a single embodiment may, for succinctness and/or to assist in understanding the scope of the disclosure, combine multiple features. It is to be understood that in such a case, these multiple features may be provided separately (in separate embodiments), or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise stated or implied. This also applies to the claims which can be recombined in any combination. That is a claim may be amended to include a feature defined in any other claim. Further a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0041] It will be appreciated by those skilled in the art that the disclosure is not restricted in its use to the particular application or applications described. Neither is the present disclosure restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the disclosure is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.