IGNITION FORMULATION AND COMBUSTIBLE COMPOSITION

Abstract

An ignition formulation for an incendiary material is disclosed. The ignition formulation comprises an initiator capable of reacting exothermically with the incendiary material to an extent sufficient to generate a flame when contacted with the incendiary material and a non-aqueous inhibitor capable of slowing the rate of exothermic reaction between the incendiary material and the initiator, thereby providing a delay period between contact of the ignition formulation with the incendiary material and generation of the flame. The non-aqueous inhibitor may be a compound selected from a group comprising, for example, long chain (C5-C12) alcohols, alkanes, alkenes, cycloalkanes, ethers, esters, ketones, carboxylic acids, aromatic hydrocarbons, organonitrates, diesel, biodiesel, kerosene, modified kerosene and oils.

Claims

1. An ignition formulation comprising: an initiator capable of reacting exothermically with an incendiary material to an extent sufficient to generate a flame when contacted therewith; and a non-aqueous inhibitor capable of slowing the rate of the exothermic reaction between the incendiary material and the initiator, wherein the ignition formulation includes a controlled ratio of the amount of the initiator to the amount of the inhibitor to provide a delay period in which a flame is generated caused by reaction between the ignition formulation with the incendiary material.

2. The ignition formulation according to claim 1, wherein the ratio of the amount of the initiator to the amount of inhibitor is in the range of 1:10 to 10:1 on a mass basis.

3. The ignition formulation according to claim 1, wherein the ratio of the amount of the initiator to the amount of inhibitor is in the range of 2:3 to 3:2 on a mass basis.

4. The ignition formulation according to claim 1, wherein the controlled ratio of the amount of the initiator to the amount of the inhibitor is provided to delay generation of a flame by a period in a range of 20 seconds to 240 seconds from a time of initial contact with the incendiary material, and ideally, in a range from 20 to 120 seconds, and even more ideally, in a range from 60 to 80 seconds.

5. The ignition formulation according to claim 1, wherein a reaction between the inhibitor and incendiary material is less exothermic than the reaction between the initiator and the incendiary material.

6. The ignition formulation according to claim 1, wherein the initiator is a hydrocarbon having from one to four carbon atoms and includes at least one hydroxyl group.

7. The ignition formulation according to claim 1, wherein the initiator is a glycol or a glycol ether.

8. The ignition formulation according to claim 1, wherein the inhibitor is combustible.

9. The ignition formulation according to claim 1, wherein the inhibitor is a hydrocarbon free of hydroxyl groups.

10. The ignition formulation according to claim 1, wherein the inhibitor is a compound selected from a group comprising long chain (C.sub.5-C.sub.12) alcohols, alkanes, alkenes, cycloalkanes, ethers, esters, ketones, carboxylic acids, aromatic hydrocarbons, organonitrates, diesel, biodiesel, kerosene, modified kerosene and oils.

11. The ignition formulation according to claim 1, further comprising a stabiliser for increasing the shelf-life of the formulation for a period of at least 4 to 6 months.

12. The ignition formulation according to claim 11, wherein the stabiliser is terpene including cyclic terpene.

13. The ignition formulation according to claim 11, wherein the stabiliser is d-limonene.

14. The ignition formulation according to claim 11, in which proportion of the amount to initiator, inhibitor to stabilizer is in the following ranges on a mass % basis to a total of 100%: Ratios Initiator 15 to 25 Inhibitor 60 to 84 Stabilizer 1 to 15

15. The ignition formulation according to claim 11, in which proportion of the amount to initiator, inhibitor and stabilizer are 20%, 75% and 5% respectively.

16. The ignition formulation according to claim 1, wherein the initiator and the inhibitor are miscible liquids.

17. The ignition formulation according to claim 1, wherein the initiator and the inhibitor are immiscible liquids.

18. The ignition formulation according to claim 17, further comprising a co-solvent in which the initiator and the inhibitor are soluble.

19. The ignition formulation according to claim 17, further comprising an agent to produce a homogenous mixture of the initiator and the inhibitor, wherein the agent comprises a surfactant or an emulsifier.

20. (canceled)

21. A combustible composition comprising Part A and Part B, wherein Part A comprises an incendiary material; and Part B comprises the ignition formulation claim 1.

22. The composition according to claim 21, wherein the incendiary material includes an oxidizing agent that reacts exothermically with the initiator.

23. The composition according to claim 21, wherein the incendiary material includes a metal oxidizing agent that reacts exothermically with the initiator.

24. The composition according to claim 21, wherein the incendiary material includes at least one of the following metal oxidizing agents that reacts exothermically with the initiator, permanganate (MnO.sub.4.sup.2+), chromate (CrO.sub.4.sup.2), dichromate (CrO.sub.4.sup.2), cobalt (Co.sub.2O.sub.3)

25. The composition according to claim 21, wherein the incendiary material is potassium permanganate.

26. The composition according to claim 21, wherein the composition includes a controlled ratio of an amount of Part A to Part B to allow complete reaction of incendiary material.

27. The composition according to claim 21, wherein the composition includes a controlled ratio of an amount of Part A to Part B at a ratio ranging from 10:1 to 5:1 on a mass basis, and preferably the ratio of Part A to Part B ranges from 3:2 to 2:3.

28. The composition according to claim 21, wherein Part A, in particulate form, is preloaded into a container, and Part B is thereafter loaded into the container, following which the initiator reacts with the incendiary material.

29. A package for using in controlled back-burning, the package including a receptacle containing an incendiary material, wherein the receptacle is adapted to receive the ignition formulation according to claim 1 to commence the reaction of the incendiary material.

30. The package according to claim 29, wherein the package is adapted to receive a controlled amount of the ignition formulation, in which a ratio of the amount of the incendiary material to the ignition formulation is in a ratio ranging from 10:1 to 5:1 on a mass basis, and preferably the ratio of the amount of the incendiary material to the ignition formulation is in ranging from 3:2 to 2:3 on an mass basis.

31-62. (canceled)

Description

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0047] Embodiments of an ignition formulation for an incendiary material, the combustible composition, a package, and a system for controlling the generation of a flame from an incendiary capsule and methods of making the ignition formulation, making the combustible composition, and igniting the incendiary capsule will now be described by way of example only, and with particular (though not exclusive) reference to providing fire control and forestry management procedures such as controlled burns and back burning.

[0048] Ignition Formulation

[0049] The ignition formulation for an incendiary material comprises an initiator capable of reacting exothermically with the incendiary material to an extent sufficient to generate a flame when contacted therewith. Generally, the incendiary material may be an oxidising agent and may, for example, be potassium permanganate, preferably in the form of granules or powder.

[0050] When the ignition formulation is in use: [0051] the initiator reacts exothermically with an incendiary material to an extent sufficient to generate a flame when contacted therewith; and [0052] the non-aqueous inhibitor slows the rate of the exothermic reaction between the incendiary material and the initiator, and [0053] wherein the ignition formulation includes a controlled ratio of the amount of the initiator to the amount of the inhibitor to provide a delay period between, contact of the ignition formulation and the incendiary material, and generation of a flame.

[0054] The initiator may be any substance capable of reacting exothermically with the incendiary material to an extent sufficient to generate a flame when contacted therewith. In one embodiment, the initiator may be a hydrocarbon having at least one hydroxyl group, such as glycol, polyol, a glycol ether or a mixture thereof. Ideally, the initiator has one to four carbon atoms.

[0055] In use, the initiator is contacted with the incendiary material by injecting the initiator into a container, such as a capsule containing the incendiary material. For convenience of use in this manner, the initiator is a liquid, preferably having a viscosity suitable for injection thereof into the container, such as a capsule. It will be appreciated by persons skilled in the art that two or more glycols, polyols or glycol ethers may be mixed to obtain an initiator liquid having suitable viscosity for injection thereof into the capsule body. For example, polyols such as glycerol are very good initiators but tend to be very viscous, whereas a mixture of glycerol with glycol ethers has lower viscosity and is still capable of reacting exothermically with the incendiary material to an extent sufficient to generate a flame when contacted therewith.

[0056] Examples of suitable glycols include, but are not limited to, glycerol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol and low molecular weight polyethylene glycols.

[0057] A polyol is an organic compound with two or more hydroxyl functional groups.

[0058] Examples of suitable polyols include, but are not limited to, diols, triols, tetrols and so forth.

[0059] Examples of suitable glycol ethers include, but are not limited to, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, monoethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether.

[0060] The ignition formulation may also comprises a non-aqueous inhibitor capable of slowing the rate of exothermic reaction between the incendiary material and the initiator, thereby providing a delay period between contact of the ignition formulation with the incendiary material and generation of the flame.

[0061] The initiator and the inhibitor are combined in a controlled ratio so as to inhibit or retard the exothermic reaction between the initiator and the incendiary material compared to a formulation or composition in which the inhibitor is absent. We have found that the ratio of the amount of the initiator to the amount of inhibitor may be in the range of 1:10 to 10:1 on a mass basis.

[0062] Advantageously, it is believed that the inhibitor acts in part as a heat sink to slow down the exothermic reaction between the incendiary material and the initiator without being vaporised to an extent sufficient to rupture the capsule, or at least not until a flame has been generated. In a preferred embodiment, the inhibitor may be combustible. Advantageously, if a combustible inhibitor is employed in the ignition formulation, the inhibitor has the effect of adding heat to the flame once generated.

[0063] Preferably, the inhibitor is non-reactive with the initiator. The inhibitor may have a melting point less than 30 C., preferably less than 0 C. The inhibitor may have a boiling point of >100 C. The inhibitor may have a flash point >63 C. The inhibitor has a high calorific value. The inhibitor preferably has low odour and low toxicity. The inhibitor may have a low vapour pressure. The inhibitor may have a low viscosity in the temperature range 0 to 40 C. However, in use in cold environments, the inhibitor may have a low viscosity in the temperature range down to 30 C.

[0064] The inhibitor may be a compound selected from a group comprising long chain (C.sub.5-C.sub.12) alcohols, alkanes, alkenes, cycloalkanes, ethers, esters, ketones, carboxylic acids, aromatic hydrocarbons, organonitrates, diesel, biodiesel, kerosene, modified kerosene and oils.

[0065] Exemplary long chain (C.sub.5-C.sub.12) alcohols include, but are not limited to, linear or branched pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol and dodecanol. Exemplary alkanes include, but are not limited to, linear or branched C.sub.4-C.sub.18 alkanes. Exemplary alkenes include, but are not limited to, linear or branched C.sub.4-C.sub.18 alkenes. Exemplary cycloalkanes include, but are not limited to, C.sub.5-C.sub.20 cycloalkanes. Exemplary ethers include, but are not limited to, ethers having mw>100. Exemplary esters include, but are not limited to, esters having mw>100.

[0066] Exemplary ketones include, but are not limited to, ketones having mw>100. Exemplary organonitrates include, but are not limited to, ethylhexyl nitrate (EHN). EHN and similar compounds in this class may be suitable because the compound is self-reactive and undergoes a self-accelerating decomposition when heated to above 100 C. Exemplary oils include, but are not limited to, mineral oils or vegetable oils, essential oils (e.g. pine oils), white oil, heating oil, white spirits and mineral turpentine.

[0067] In use, the inhibitor is mixed with the initiator, and the resulting mixture may be later injected into the container body containing the incendiary material just prior to deployment of the incendiary container.

[0068] The ignition formulation may have a shelf-life of 1 to 4 weeks. In order to increase the shelf-life of the ignition formulation, a stabilizer for increasing the shelf-life to of range of, for example, 4 to 6 months may be added. In other examples, the shelf-life provided by the stabilizer could be more.

[0069] The stabilizer may be any suitable material that preserves the reactivity of the initiator. In one embodiment, the stabilizer may be a terpene. A suitable example of terpene includes cyclic terpene. An example of a cyclic terpene is limonene and a suitable isomer is d-limonene.

[0070] The ignition formulation may also include the initiator, inhibitor and stabilizer in the following ratios.

TABLE-US-00002 TABLE 1 Range Range Range Range Range Range 1 2 3 4 5 6 Initiator 5 to 55 5 to 45 5 to 35 10 to 30 15 to 25 20 Inhib- 44 to 94 30 to 94 40 to 94 50 to 89 60 to 84 75 itor Stabi- 1 to 25 1 to 25 1 to 25 1 to 20 1 to 15 5 lizer

[0071] In one embodiment the initiator and the inhibitor are miscible liquids.

[0072] In alternative embodiments the initiator and the inhibitor may be immiscible liquids. A mixture of immiscible liquids may separate over time into a bi-liquid phase which is undesirable for several reasons. In these particular embodiments the formulation may be adapted to provide a stable homogenous mixture of the immiscible initiator and the inhibitor.

[0073] For example, the ignition formulation may further comprise a co-solvent in which the initiator and the inhibitor are soluble. Examples of suitable co-solvents include, but are not limited to, long chain (C.sub.5-C.sub.12) alcohols, esters such as amyl acetate and n-pentyl propionate, ethers such as dilauryl ether, glycol ether acetates such as 2-(2-butoxyethoxy)-ethyl acetate, glycol ethers, solvents such as N-methyl-pyrrolidone, gamma butyrolactone, 1,4-dioxane. It will be appreciated that in some embodiments mixtures of one or more co-solvents may be employed in the ignition formulation.

[0074] Alternatively, the ignition formulation may further comprise an agent capable of forming a stable homogenous mixture of the immiscible initiator and the inhibitor, preferably in the form of an emulsion. Suitable agents include, but are not limited to, emulsifiers or surfactants. Exemplary emulsifiers include, but are not limited to, alcohol ethoxylates, alkylphenol ethoxylates, fatty acid ethoxylates, sorbitan esters including laurates, myristates and oleates, sorbitan ester ethoxylates or polysorbates, or mixtures thereof.

[0075] In preferred embodiments, two or more emulsifiers may be employed. Particularly preferred are those emulsifiers having low hydrophile lipophile balance (hlb) number or emulsifiers with a relatively low degree of ethoxylation.

[0076] It will be appreciated that the ignition time may be influenced by the purity of the potassium permanganate employed as the incendiary material, the particle size of the crystals or granules and the ambient temperature.

[0077] The initiator and the inhibitor may be provided in a ratio to delay generation of a flame by a period in a range of 20 seconds to 120 seconds from a time of initial contact with the incendiary material. The ratio of initiator to inhibitor may be in the range of 1:10 to 10:1.

[0078] Combustible Composition, System and Package for Controlling the Generation of a Flame

[0079] The system or package for controlling the generation of a flame from a combustible composition comprises a quantity of incendiary material in a receptacle of a container, such as a sealed capsule; and an ignition formulation as described herein.

[0080] The container comprises a receptacle portion and a planar lid, wherein the lid is adhered to the receptacle to define a space in which the incendiary material is held and into which the ignition formulation can be injected.

[0081] The container may be conveniently fabricated from a plastics material. The term plastics material is intended to be interpreted broadly to encompass synthetic or fossil fuel derived plastics material and bioplastics material, unless from the specific context of the use of the term an alternate meaning is clearly intended. The term bioplastic is intended to be interpreted broadly to encompass forms of plastics which are able to biodegrade in time and thereby minimise adverse environmental effects. Non limiting examples of synthetic or fossil fuel derived plastics material are: polyethylene terephthalate; high-density polyethylene; polyvinyl chloride; low-density polyethylene;

[0082] and polypropylene. Non limiting examples of bioplastics are: starch based plastics, cellulose based plastics, bioplastic derived from microbiota; and polylactic acid (PLA) plastics.

[0083] Preferably, the package, container or capsule is fabricated from an ABS plastics material.

[0084] The system also comprises an injector for injecting the ignition formulation into the capsule body.

[0085] The system may further comprise a dispenser for dispensing the capsule body injected with the ignition formulation. The dispenser may be configured for dispensing said injected capsule bodies from an air-borne vehicle, a land vehicle, or by a ground-based operator. Exemplary dispensers have been described in Australian patent no. 2003204999; and application numbers 2010256280; 2011223497; and 2011293093.

[0086] Method of Making an Ignition Formulation for an Incendiary Material

[0087] The method of making an ignition formulation for an incendiary material may comprise mixing an initiator, wherein the initiator is capable of reacting exothermically with the incendiary material to an extent sufficient to generate a flame when contacted therewith, with an inhibitor capable of slowing the rate of exothermic reaction between the incendiary material and the initiator. The relative amounts of the initiator and inhibitor mixed together are controlled in a ratio so to provide a delay period between contact of the ignition formulation with the incendiary material and generation of the flame.

[0088] The initiator and inhibitor are as described previously.

[0089] The ratio of the initiator to the inhibitor may be in the range of 1:10 to 10:1 on a mass basis. The ratio of the initiator to the inhibitor may be in the range of 2:3 to 3:2 on a mass basis.

[0090] The method of making the ignition formulation may also include combining, and suitably mixing the initiator, inhibitor and stabilizer in accordance with any one of the ranges (Ranges 1 to 6) of ratios provided in Table 1.

[0091] Method of Making a Combustible Composition

[0092] A method of making a combustible composition including the steps of: a) providing an incendiary material in a container; forming an ignition formulation by combining i) an initiator capable of reacting exothermically with the incendiary material to an extent sufficient to generate a flame when contacted therewith, and ii) a non-aqueous inhibitor capable of slowing the rate of exothermic reaction between the incendiary material and the initiator, wherein step b) includes combining an amount of the initiator and an amount of the inhibitor at a controlled ratio to provide a delay period between contact of the ignition formulation with the incendiary material and generation of the flame.

[0093] The method may include loading the ignition formulation formed in step b) into the container, for example, by injecting, to allow the initiator to react with the incendiary material over a delayed period.

[0094] The method may include loading the incendiary material into a container which is preferably a sealed capsule.

[0095] The incendiary material includes an oxidizing agent in a granular form. Example include: permanganate (MnO.sub.4.sup.2+), chromate (CrO.sub.4.sup.2), dichromate (CrO.sub.4.sup.2), cobalt (Co.sub.2O.sub.3). The permanganate ion may be with barium, calcium, sodium, ammonium, but is suitably potassium permanganate.

[0096] The method may also include controlling relative amounts of the incendiary material and the ignition formulation loaded into each container such that a ratio of incendiary material to ignition formulation ranges from 10:1 to 5:1 on a mass basis. The ratio may also be in the range of 3:2 to 2:3.

[0097] Method of Controlling the Generation of a Flame from an Incendiary Capsule

[0098] Said method comprises injecting the ignition formulation as described above into the capsule body, thereby causing a delay period between contact of the ignition formulation with the incendiary material and generation of the flame.

[0099] The injected capsules are then immediately dispensed from air-borne vehicle (i.e. light aircraft or helicopter) to the desired area. Typically, the injected capsules are dispensed from an altitude of 100 to 6000 feet. The delay period between contact of the ignition formulation with the incendiary material and generation of the flame allows the injected capsule to clear the vicinity of the air-borne vehicle before ignition. Moreover, the delay period means that the incendiary capsule is likely to generate a flame on or proximal to the ground rather than mid-air.

[0100] In an alternative embodiment, the injected capsules may be immediately dispensed to the desired area from a land vehicle or from a hand-held propulsion device by ground-based operators. The delay period between contact of the ignition formulation with the incendiary material and generation of the flame allows the land vehicle or the ground-based operators to clear the vicinity of the injected capsule before ignition.

[0101] In another alternative embodiment, the injected capsules may be immediately dispensed to the desired area from a water-borne vehicle. The dealy period between contact of the ignition formulation with the incendiary material and generation of the flame allows water-borne vehicle to clear the vicinity of the injected capsule before ignition.

EXAMPLES

[0102] A preferred embodiment of an ignition formulation for controlling the generation of a flame from an incendiary material now be described.

[0103] Stoichiometrically, the ratio of glycerol to potassium permanganate is approximately 1:6 by weight according to the reaction:

14KMnO.sub.4+4CH(OH)(CH.sub.2OH).sub.2.fwdarw.K.sub.2CO.sub.3+7Mn.sub.2O.sub.3+5CO.sub.2+16H.sub.2O

For ethylene glycol the ratio is practically the same:

14KMnO.sub.4+6(CH.sub.2OH).sub.2.fwdarw.K.sub.2CO.sub.3+7Mn.sub.2O.sub.3+5CO.sub.2+16H.sub.2O

[0104] Preferably, the incendiary material (e.g. potassium permanganate) may be ignited by injecting the ethylene glycol at any ratio from about 1 part ethylene glycol to 10 parts permanganate to 1 part ethylene glycol to 3 parts permanganate. Ideally, the ignition formulation also includes a stabilizer, such as d-limonene to increase the shelf-life of the ignition formulation to approximately 4 to 6 months. However, the shelf-life provided by the stabilizer may be longer.

[0105] In one example, the ignition formulation comprises approximately 20% monoethylene glycol as the initiator, 75% butyl glycol ether as the inhibitor, and approximately 5% d-limonene as the stabilizer.

[0106] In the examples of ignition formulation described below, 0.15 to 0.3 mL ignition formulation is injected into a capsule body containing 1.42 g potassium permanganate. The ignition formulation is provided with and without stabilizer. This is equivalent to a ratio of approximately 1 part liquid to 10 parts KMnO.sub.4 by weight to 1 part liquid to 5 parts KMnO.sub.4 by weight.

[0107] The examples below are designed to provide a delay from injection to generation of the flame of about 25 seconds at ambient temperature 30 C. to 35 C.

Example 1

[0108]

TABLE-US-00003 Ignition formulation % w/w % w/w Initiator Monoethylene glycol 25 20 Inhibitor Dodecanolbuty glycol ether 75 75 Stabilizer Terpene 5

Example 2

[0109]

TABLE-US-00004 Ignition formulation % w/w % w/w Initiator Diethylene glycol monobutyl ether 55 50 Inhibitor Dodecanol 45 45 Stabilizer Terpene 5

Example 3

[0110]

TABLE-US-00005 Ignition formulation % w/w % w/w Initiator Diethylene glycol monobutyl ether 60 55 Inhibitor Dearomatised kerosene 30 30 Inhibitor Octanol 10 10 Stabilizer Terpene 5

Example 4

[0111]

TABLE-US-00006 Ignition formulation % w/w % w/w Initiator Diethylene glycol monoethyl ether 40 35 Inhibitor 2-(2-butoxyethoxy)-ethyl acetate 30 30 Inhibitor Diesel fuel 30 30 Stabilizer Terpene 5

Example 5

[0112]

TABLE-US-00007 Ignition formulation % w/w % w/w Initiator Diethylene glycol monoethyl ether 40 35 Inhibitor Dearomatised kerosene 30 30 Inhibitor Nonylphenol ethoxylate 20 20 Stabilizer Terpene 5

Example 6

[0113]

TABLE-US-00008 Ignition formulation % w/w % w/w Initiator Diethylene glycol monoethyl ether 50 45 Inhibitor Dearomatised kerosene 30 30 Inhibitor Octanol 10 10 Inhibitor Ethylhexyl nitrate 10 10 Stabilizer Terpene 5

Example 7

[0114]

TABLE-US-00009 Ignition formulation % w/w % w/w Initiator Ethylene glycol 25 20 Initiator Diethylene glycol 25 25 Inhibitor Amyl acetate 10 10 Inhibitor Dodecanol 40 40 Stabilizer Terpene 5

Example 8

[0115]

TABLE-US-00010 Ignition formulation % w/w % w/w Initiator Diethylene glycol monoethyl ether 60 55 Inhibitor Mineral oil 25 25 Inhibitor Alcohol ethoxylate blend 15 15 Stabilizer Terpene 5

[0116] Numerous variations and modifications will suggest themselves to persons skilled in the relevant art, in addition to those already described, without departing from the disclosure. All such variations and modifications are to be considered within the scope of the disclosure.

[0117] In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word comprise and variations such as comprises or comprising are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of formulation, system and methods as disclosed herein.