Patent Application
20180215679
The present disclosure relates to an ignition formulation for an incendiary material, a combustible composition, and a package containing the incendiary material and the ignition formulation. The present disclosure also relates to methods of making the ignition formulation and the combustible composition, and a system for controlling generation of a flame from an incendiary container. An exemplary use for the ignition formulation and said system is for fire control and forestry management procedures such as controlled burns and back burning.
The present Applicant has developed numerous incendiary capsules and machines for airborne dispensing of incendiary capsules. Examples of these are described in Australian patent no. 2003204999; and application numbers 2010256280; 2011223497; and 2011293093. The incendiary material used in each instance comprises at least potassium permanganate. The potassium permanganate is held within a capsule. The capsules are subsequently injected with an initiator in the form of a glycol using an automated dispensing machine and subsequently dropped to the ground. The dispensing machine can be mounted in or on an aircraft so that the capsules once injected with the initiator are dropped from the aircraft to fall to the ground.
The potassium permanganate and initiator react exothermically to produce a flame. Efficacy is maximised if the flame is generated when the capsule is on the ground rather than in the air. In order to exert some control over the period of time between initial injection of the initiator and the production of a flame, third parties have been known to mix glycol with water. This slows the exothermic reaction providing sufficient time for the capsule to reach the ground prior to the generation of the flame. Injection of a mixture of water and glycol into a capsule of potassium permanganate has however been known to cause the capsule to explode due to the generation of steam prior to the generation of a flame. Moreover, the presence of water may quench the flame or at least reduce flame size.
The above references to background art do not constitute an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art. The above references are also not intended to limit the application of the formulation, system and methods as disclosed herein.
The general concept of the present disclosure is to provide an ignition formulation and a combustible composition for controlling the generation of a flame from an incendiary package in which ignition time of the incendiary material can be controlled or at least delayed in comparison to other equivalent packages that do not include the ignition formulation of the present disclosure. The present disclosure is based on a discovery that the ignition time can be controlled and/or delayed by the addition of an inhibitor capable of slowing the rate of exothermic reaction between the incendiary material, for example potassium permanganate and reaction initiator, for example glycol or other initiators, thereby providing a delay period between contact of the glycol-inhibitor mixture with potassium permanganate and generation of the flame.
In one aspect, there is disclosed an ignition formulation comprising:
The initiator and the inhibitor may be provided at ratio in which the amount of the initiator to the amount of inhibitor is in the range of 1:10 to 10:1 on a mass basis. The ratio may also be in the range of 2:3 to 3:2 on a mass basis, or possibly 1:1 on a mass basis.
Without wanting to be limited by theory, it is possible that the inhibitor may reduce the rate of the exothermic reaction between the incendiary material and the initiator by either one or a combination of: i) the inhibitor behaving as a heat sink prior to generation of the flame, and/or ii) the inhibitor diluting the initiator. In any event, by controlling the ratio of the amount of the inhibitor to the amount of the initiator, a delay period is provided between contact of the ignition formulation with the incendiary material and generation of the flame.
In one embodiment, the initiator and the inhibitor are provided in a control ratio 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. The initiator and the inhibitor may be provided in a control ratio to delay generation of a flame by a period in a range of 20 to 120 seconds, or possibly in a range from 60 to 80 seconds. When the inhibitor is absent, depending a range of factors such that the particle size distribution of the incendiary material, reaction between the incendiary material and the initiator can generate a flame in less than 20 seconds.
The inhibitor may or may not react with the incendiary material. In the situation in which the inhibitor does react with the incendiary material, ideally the reaction between the inhibitor and incendiary material is less exothermic than the reaction between the initiator and the incendiary material.
The initiator may be a hydrocarbon having at least one hydroxyl group. The initiator may be a hydrocarbon having one to four carbon atoms. Examples of possible initiators include, glycol, polyol, a glycol ether or a mixture thereof.
The inhibitor may be a hydrocarbon. Suitably the inhibitor may be a hydrocarbon that is free of hydroxyl groups. In the instance when the inhibitor is a hydrocarbon having hydroxyl groups, ideally the inhibitor has from 5 to 20 carbon atoms, or suitably 5 to 20 carbon atoms.
The inhibitor may be a compound selected from a group comprising long chain (C5-C12) alcohols, alkanes, alkenes, cycloalkanes, ethers, esters, ketones, carboxylic acids, aromatic hydrocarbons, organonitrates, diesel, biodiesel, kerosene, modified kerosene and oils.
In preferred embodiments, the inhibitor may be combustible. Although the presence of the inhibitor may delay the onset of a flame when the initiator is mixed with the incendiary material, once the flame is generated the inhibitor can combusts and enhance the generated flame.
In one embodiment the initiator and the inhibitor may be miscible liquids.
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.
For example, the ignition formulation may further comprise a co-solvent in which the initiator and the inhibitor are soluble. 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 or microemulsion. Examples of suitable agents include, but are not limited to, emulsifiers or surfactants.
The ignition formulation may have a shelf-life of one to two weeks during which the ignition formulation can be used to generate a flame with the incendiary material. Beyond the usable shelf-life, the ignition formulation may fail to generate a flame.
The ignition formulation may, however, include a stabilizer for increasing the shelf-life of the formulation. For example, the shelf-life that the stabilizer may provide could range from 4 to 6 months from when the ignition formulation is composed. In other examples, the shelf life could be more.
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.
Without wanting to be limited by theory, the stabilizer may have the effect of preserving the hydroxyl groups of initiator.
The stabilizer may be present in the ignition formula in an amount up to 15% by weight, and suitably up to 10% by weight and even more suitably 5% by weight.
The ignition formulation may include the initiator, inhibitor and stabilizer in any one of the following ranges on a % mass basis in which the total initiator, inhibitor and stabilizer is 100%.
In another aspect, there is provided a combustible composition comprising:
Part A and Part B are kept out of contact with each other prior to use, and are brought into contact during use to generate the flame.
The incendiary material may include an oxidizing agent that reacts exothermically with the initiator. For example, the incendiary material may include a metal oxidizing agent that reacts exothermically with the initiator. Possible examples of metal oxidants include permanganate (MnO42+), chromate (CrO42−), dichromate (CrO42−), cobalt (Co2O3). The permanganate ion may be with, for example, sodium, calcium, potassium and ammonium.
In one embodiment, the incendiary material may be potassium permanganate.
Ideally the composition includes a controlled ratio of an amount of Part A to Part B to allow complete reaction of incendiary material. For example, a ratio of an amount of Part A to Part B may range from 10:1 to 5:1 on a mass basis. The ratio of Part A to Part B may also range from 3:2 to 2:3, or be approximately 1:1 on a mass basis.
The composition may include Part A, in particulate form that may be preloaded into a container, and Part B, in a liquid form that may be loaded into the container, to commence the reaction between the initiator and the incendiary material.
In another aspect there is provided 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 described herein.
In another aspect there is provided a system for controlling the generation of a flame from an incendiary capsule is disclosed. The system comprises a quantity of incendiary material sealed in a capsule body and an ignition formulation as described herein. The system may further comprise a means for injecting the ignition formulation into the capsule body.
In another aspect, there is disclosed a method of making an ignition formulation for an incendiary material. The method including the steps of:
In another aspect there is disclosed a method of making a combustible composition, the method including the steps of:
In another aspect there is disclosed a method of controlling the generation of a flame from an incendiary capsule comprising a quantity of incendiary material sealed in a capsule body is also disclosed. The method comprises injecting the ignition formulation as described herein into the capsule body, thereby causing a delay period between contact of the ignition formulation with the incendiary material and generation of the flame.
The ignition formulation may include any one or a combination to the features of the combustible composition and vice versa.
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.
Ignition Formulation
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.
When the ignition formulation is in use:
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.
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.
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.
A polyol is an organic compound with two or more hydroxyl functional groups.
Examples of suitable polyols include, but are not limited to, diols, triols, tetrols and so forth.
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.
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.
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.
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.
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.
The inhibitor may be a compound selected from a group comprising long chain (C5-C12) alcohols, alkanes, alkenes, cycloalkanes, ethers, esters, ketones, carboxylic acids, aromatic hydrocarbons, organonitrates, diesel, biodiesel, kerosene, modified kerosene and oils.
Exemplary long chain (C5-C12) 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 C4-C18 alkanes. Exemplary alkenes include, but are not limited to, linear or branched C4-C18 alkenes. Exemplary cycloalkanes include, but are not limited to, C5-C20 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.
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.
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.
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.
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.
The ignition formulation may also include the initiator, inhibitor and stabilizer in the following ratios.
In one embodiment the initiator and the inhibitor are miscible liquids.
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.
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 (C5-C12) 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.
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.
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.
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.
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.
Combustible Composition, System and Package for Controlling the Generation of a Flame
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.
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.
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;
and polypropylene. Non limiting examples of bioplastics are: starch based plastics, cellulose based plastics, bioplastic derived from microbiota; and polylactic acid (PLA) plastics.
Preferably, the package, container or capsule is fabricated from an ABS plastics material.
The system also comprises an injector for injecting the ignition formulation into the capsule body.
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.
Method of Making an Ignition Formulation for an Incendiary Material
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.
The initiator and inhibitor are as described previously.
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.
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.
Method of Making a Combustible Composition
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.
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.
The method may include loading the incendiary material into a container which is preferably a sealed capsule.
The incendiary material includes an oxidizing agent in a granular form. Example include: permanganate (MnO42+), chromate (CrO42−), dichromate (CrO42−), cobalt (Co2O3). The permanganate ion may be with barium, calcium, sodium, ammonium, but is suitably potassium permanganate.
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.
Method of Controlling the Generation of a Flame from an Incendiary Capsule
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.
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.
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.
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.
A preferred embodiment of an ignition formulation for controlling the generation of a flame from an incendiary material now be described.
Stoichiometrically, the ratio of glycerol to potassium permanganate is approximately 1:6 by weight according to the reaction:
14KMnO4+4CH(OH)(CH2OH)2→K2CO3+7Mn2O3+5CO2+16H2O
For ethylene glycol the ratio is practically the same:
14KMnO4+6(CH2OH)2→K2CO3+7Mn2O3+5CO2+16H2O
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.
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.
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 KMnO4 by weight to 1 part liquid to 5 parts KMnO4 by weight.
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.
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.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014901047 | Mar 2014 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2015/000175 | 3/24/2015 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61975097 | Apr 2014 | US |
