THE PRODUCTION THEREOF

FIELD OF INVENTION [0001] The present invention relates generally to waterproofing combustible materials, such as torrified wood pellets, other biomass materials such as pelletized biomass materials, and/or coal or coal fines. More specifically, the present invention relates to polymer-coated combustible pellets, such as torrified wood pellets, other biomass materials, or coal fines, where the polymer coating may be derived from waste materials.

BACKGROUND

[0002] Torrified wood pellets may be an excellent clean green replacement for coal, but they suffer from two significant problems. First, they are not waterproof. If traditional torrified wood pellets are exposed to excess moisture or liquid water, they will adsorb water causing the pellets to swell and to fall apart, which renders them ineffective as a fuel. Wood pellets may act similarly in the presence of excess moisture or liquid water. The second problem is that, compared with coal, standard torrified wood pellets may have low energy density. For either of standard torrified wood and coal fines pellets, water exposure may create difficulties.

[0003] Plastic waste, such as styrofoam (also referred to as expanded polystyrene foam, EPS, polystyrene, such as, for example, Styrofoam ^® ), is difficult to recycle and does not burn cleanly. Accordingly, methods of disposal of plastics like styrofoam are limited. Currently, in many jurisdictions styrofoam is landfilled, which adds to the environmental waste problem. Styrofoam is a major component in some landfills. In certain jurisdictions, styrofoam waste is burned, however the material burns poorly, smouldering and releasing black acrid smoke containing toxic compounds including polyaromatic hydrocarbons and benzene. The melting point of styrofoam is 240 °C while the decomposition temperature is 300°C. The auto ignition temperature of the vapours given off from heated styrene is 427 °C [1], Pleating styrofoam in air is known to produce styrene, benzene, toluene and xylene [2], Benzene is a known carcinogen. [0004] A cost-effective and/or environmentally friendly method of making combustible pellets, such as torrified wood pellets, water-resistant is desirable. Increasing the energy density of combustible pellets, such as torrified wood pellets, is also desirable. Processes for enhanced or complete styrofoam combustion, converting styrofoam to C0 and water vapour through burning, are also desirable.

SUMMARY OF INVENTION

[0005] Biomass materials such as torrified wood pellets may provide a green alternative to coal. However, traditional torrified wood pellets and other such materials absorb water, causing swelling and hindering use as a fuel. Maintaining dryness complicates transport and storage, for example. As well, energy density of traditional torrified wood pellets and other such materials is typically low. For either of standard torrified wood and coal fines pellets, water exposure may create difficulties.

[0006] Organic or plastic waste, such as styrofoam and other such materials, is difficult to recycle and does not burn cleanly, and so in many instances styrofoam is landfilled, creating environmental issues.

[0007] As described in detail herein, methods have now been developed for preparing combustible materials (such as torrified wood and coal fines) coated with an organic polymer or plastic (such as styrofoam), providing coated materials which are substantially waterproof or water-resistant. Resultant coated materials may provide a good fuel source which may be substantially resistant to water absorption and/or adsorption than comparable uncoated material and may provide good energy density, while also diverting waste organics/plastics (such as styrofoam) away from landfills.

[0008] In an embodiment, there is provided herein a solid fuel comprising a combustible material coated with an organic material or plastic, the solid-fuel being substantially water-resistant or waterproof (e.g. more resistant to water absorption and/or adsorption than comparable uncoated combustible material).

[0009] In another embodiment of the above solid fuel, the combustible material may comprise wood, torrified wood, another biomass material, coal, coal fines, or another carbonaceous material or plant- derived material.

[0010] In still another embodiment of any of the above solid fuel or solid fuels, the combustible material may be in the form of pellets, fines, grounds, or another structure having a size ranging from about 10 microns to about 10 cm, or any subrange or value therein. In certain embodiments, the biomass material may be in the form of pellets, fines, or another structure having a size ranging from about 0.01cm to about 3 cm, or any subrange or value therein.

[0011] In yet another embodiment of any of the above solid fuel or solid fuels, the combustible material may comprise torrified wood (pellets or otherwise) or coal fines.

[0012] In another embodiment of any of the above solid fuel or solid fuels, the combustible material may comprise torrified wood pellets, and the torrified wood pellets may be coated with the organic material or plastic.

[0013] In still another embodiment of any of the above solid fuel or solid fuels, the combustible material may comprise coal fines, the coal fines may be coated with the organic material or plastic, and the solid fuel may be provided as pellets formed by pressing the coated coal fines.

[0014] In yet another embodiment of any of the above solid fuel or solid fuels, the organic material or plastic may comprise an organic polymeric coating or plastic material derived from a waste material.

[0015] In yet another embodiment of any of the above solid fuel or solid fuels, the organic material or plastic may comprise styrofoam, Styrene, polystyrene, Acrylonitrile butadiene styrene (ABS), Poly(methyl methacrylate), Acrylic, low density polyethylene (LDPE), or another organic polymer that is soluble in a non-aqueous solvent.

[0016] In another embodiment of any of the above solid fuel or solid fuels, the organic material or plastic may comprise styrofoam, extruded polystyrene foam, polystyrene, or Acrylonitrile butadiene styrene (ABS).

[0017] In still another embodiment of any of the above solid fuel or solid fuels, the combustible material may be coated with the organic material or plastic by preparing a solution of the organic material or plastic in a solvent, applying the solution to the combustible material, and evaporating the solvent from the combustible material.

[0018] In yet another embodiment of any of the above solid fuel or solid fuels, the solvent may comprise a non-polar, low-polarity, or mid polarity solvent.

[0019] In yet another embodiment of any of the above solid fuel or solid fuels, the solvent may comprise one or more of chloroform, acetone, methyl ethyl ketone, ethyl acetate, benzene, toluene, xylene, gasoline, or another organic solvent that dissolves plastic. [0020] In still another embodiment of any of the above solid fuel or solid fuels, the solvent may comprise toluene.

[0021] In another embodiment of any of the above solid fuel or solid fuels, the organic material or plastic may comprise styrofoam.

[0022] In yet another embodiment of any of the above solid fuel or solid fuels, the solvent may comprise methyl ethyl ketone (MEK), acetone, or chloroform.

[0023] In still another embodiment of any of the above solid fuel or solid fuels, the organic material or plastic may comprise ABS.

[0024] In yet another embodiment of any of the above solid fuel or solid fuels, the solution of organic material or plastic in a solvent may comprise at least about 0.01 g/mL, at least about 0.02 g/mL, at least about 0.03 g/mL, at least about 0.04 g/mL, at least about 0.05 g/mL, at least about 0.06 g/mL, at least about 0.07 g/mL, at least about 0.08 g/mL, at least about 0.09 g/mL, at least about 0.10 g/mL, at least about 0.11 g/mL, at least about 0.12 g/mL, at least about 0.13 g/mL, at least about 0.14 g/mL, at least about 0.15 g/mL, at least about 0.16 g/mL, at least about 0.17 g/mL, at least about 0.18 g/mL, at least about 0.19 g/mL, at least about 0.20 g/mL, at least about 0.21 g/mL, at least about 0.22 g/mL, at least about 0.23 g/mL, at least about 0.24 g/mL, at least about 0.25 g/mL, at least about 0.26 g/mL, at least about 0.27 g/mL, at least about 0.28 g/mL, at least about 0.29 g/m L, or at least about 0.30 g/mL organic material or plastic. In certain embodiments, the solution may comprise about 0.01 g/mL to about 0.30 g/mL organic material or plastic, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01. In certain embodiments, the solution may comprise about 0.05 g/mLto about 0.25 g/mL, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01.

[0025] In still another embodiment of any of the above solid fuel or solid fuels, the solution may be applied to the combustible material by spraying, by temporarily immersing the combustible material in the solution, or by mixing the combustible material with the solution.

[0026] In another embodiment of any of the above solid fuel or solid fuels, the solid fuel may be resistant to absorption of water for at least about 5 minutes, at least about 1 hour, at least about 1 day, at least about 1 week, at least about 1 month, at least about 6 months, or at least about 1 year, when immersed in water. In another embodiment, the solid fuel may be resistant to absorption of water when immersed in water for a particular duration of time selected from a range of from about 5 minutes to about 6 months, or more, or any sub-range falling therein.

[0027] In yet another embodiment of any of the above solid fuel or solid fuels, the solid fuel may have a calorific value in MJ/Kg which is at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 11%, at least about 12%, at least about 13%, at least about 14%, at least about 15%, at least about 16%, at least about 17%, at least about 18%, at least about 19%, at least about 20%, at least about 21%, at least about 22%, at least about 23%, at least about 24%, at least about 25%, at least about 26%, at least about 27%, at least about 28%, at least about 29%, at least about 30%, at least about 31%, at least about 32%, at least about 33%, at least about 34%, at least about 35%, at least about 36%, at least about 37%, or at least about 38% greater than that of an uncoated combustible material control. In certain embodiments of any of the above solid fuel or solid fuels, the solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 50% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%. In certain embodiments, the solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 38% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0028] In yet another embodiment of any of the above solid fuel or solid fuels, the solid fuel may comprise about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, or about 45% coating (i.e. the organic material or plastic coating) by weight. In certain embodiments, the solid fuel may comprise about 5% to about 45% coating (i.e. the organic material or plastic coating) by weight, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0029] In still another embodiment of any of the above solid fuel or solid fuels, the solid fuel may burn at temperature lower than that of a control organic material or plastic alone; wherein the solid fuel may produce less harmful combustion product as compared with a control organic material or plastic alone; or both. In another embodiment, the harmful combustion product may comprise benzene, polyaromatic hydrocarbons, or both. [0030] In another embodiment, there is provided herein a use of a solid fuel as described herein for producing energy by combustion.

[0031] In another embodiment, there is provided herein a solid fuel as described herein for producing energy by combustion. [0032] In still another embodiment, there is provided herein a method for producing energy, comprising combusting a solid fuel as described herein.

[0033] In yet another embodiment, there is provided herein a method for producing a water-resistant or waterproof solid fuel comprising a combustible material coated with an organic material or plastic, said method comprising: providing a solution comprising the organic material or plastic in a solvent;

applying the solution to the combustible material; and

evaporating the solvent, thereby providing the water-resistant or waterproof solid fuel comprising the combustible material coated with the organic material or plastic. [0034] In another embodiment of the above method, the combustible material may comprise wood, torrified wood, another biomass material, coal, coal fines, or another carbonaceous material or plant- derived material.

[0035] In still another embodiment of any of the above method or methods, the combustible material may be in the form of pellets, fines, grounds, or another structure having a size ranging from about 10 microns to about 10 cm, or any subrange or value therebetween. In certain embodiments, the combustible material may be in the form of pellets, fines, or another structure having a size ranging from about 0.01 cm to about 3 cm, or any subrange or value therebetween.

[0036] In yet another embodiment of any of the above method or methods, the combustible material may comprise torrified wood (pellets or otherwise) or coal fines. [0037] In another embodiment of any of the above method or methods, the combustible material may comprise torrified wood pellets, and the torrified wood pellets may be coated with the organic material or plastic. [0038] In still another embodiment of any of the above method or methods, the combustible material may comprise coal fines, the coal fines may be coated with the organic material or plastic, and the solid fuel may be provided as pellets formed by pressing the coated coal fines.

[0039] In yet another embodiment of any of the above method or methods, the organic material or plastic may comprise an organic polymeric coating or plastic material derived from a waste material.

[0040] In another embodiment of any of the above method or methods, the organic material or plastic may comprise styrofoam, Styrene, polystyrene, Acrylonitrile butadiene styrene (ABS), Poly(methyl methacrylate), Acrylic, low density polyethylene (LDPE), or another organic polymer that is soluble in a non-aqueous solvent. [0041] In still another embodiment of any of the above method or methods, the organic material or plastic may comprise styrofoam, extruded polystyrene foam, polystyrene, or Acrylonitrile butadiene styrene (ABS).

[0042] In yet another embodiment of any of the above method or methods, the step of providing the solution may comprise dissolving the organic material or plastic in the solvent. [0043] In another embodiment of any of the above method or methods, the solvent may comprise a non polar, low-polarity, or mid polarity solvent.

[0044] In still another embodiment of any of the above method or methods, the solvent may comprise one or more of chloroform, acetone, methyl ethyl ketone, ethyl acetate, benzene, toluene, xylene, gasoline, or another organic solvent that dissolves plastic. [0045] In yet another embodiment of any of the above method or methods, the solvent may comprise toluene.

[0046] In still another embodiment of any of the above method or methods, the organic material or plastic may comprise styrofoam.

[0047] In another embodiment of any of the above method or methods, the solvent may comprise methyl ethyl ketone (MEK), acetone, or chloroform.

[0048] In yet another embodiment of any of the above method or methods, the organic material or plastic may comprise ABS. [0049] In another embodiment of any of the above method or methods, the solution of organic material or plastic in a solvent may comprise at least about 0.01 g/mL, at least about 0.02 g/mL, at least about 0.03 g/mL, at least about 0.04 g/mL, at least about 0.05 g/mL, at least about 0.06 g/mL, at least about 0.07 g/mL, at least about 0.08 g/mL, at least about 0.09 g/mL, at least about 0.10 g/mL, at least about 0.11 g/mL, at least about 0.12 g/mL, at least about 0.13 g/mL, at least about 0.14 g/m L, at least about 0.15 g/mL, at least about 0.16 g/mL, at least about 0.17 g/mL, at least about 0.18 g/mL, at least about 0.19 g/mL, at least about 0.20 g/mL, at least about 0.21 g/mL, at least about 0.22 g/mL, at least about 0.23 g/mL, at least about 0.24 g/mL, at least about 0.25 g/mL, at least about 0.26 g/mL, at least about 0.27 g/mL, at least about 0.28 g/mL, at least about 0.29 g/mL, or at least about 0.30 g/mL organic material or plastic. In certain embodiments, the solution may comprise about 0.01 g/mL to about 0.30 g/mL organic material or plastic, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01. In certain embodiments, the solution may comprise about 0.05 g/mL to about 0.25 g/mL, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01.

[0050] In another embodiment of any of the above method or methods, the step of applying the solution to the combustible material may comprise spraying or physically painting the solution onto the combustible material; temporarily immersing the combustible material in the solution; passing the combustible material through a waterfall or stream of the solution (on an assembly line, for example); or mixing the combustible material with the solution.

[0051] In still another embodiment of any of the above method or methods, the resultant solid fuel may be resistant to absorption of water for at least about 5 minutes, at least about 1 hour, at least about 1 day, at least about 1 week, at least about 1 month, at least about 6 months, or at least about 1 year, when immersed in water. In another embodiment, the solid fuel may be resistant to absorption of water when immersed in water for a particular duration of time selected from a range of from about 5 minutes to about 6 months, or more, or any sub-range falling therein.

[0052] In another embodiment of any of the above method or methods, the resultant solid fuel may have a calorific value in MJ/Kg which is at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 11%, at least about 12%, at least about 13%, at least about 14%, at least about 15%, at least about 16%, at least about 17%, at least about 18%, at least about 19%, at least about 20%, at least about 21%, at least about 22%, at least about 23%, at least about 24%, at least about 25%, at least about 26%, at least about 27%, at least about 28%, at least about 29%, at least about 30%, at least about 31%, at least about 32%, at least about 33%, at least about 34%, at least about 35%, at least about 36%, at least about 37%, or at least about 38% greater than that of an uncoated combustible material control. In certain embodiments, the resultant solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 50% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%. In certain embodiments, the resultant solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 38% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0053] In yet another embodiment of any of the above method or methods, the resultant solid fuel may comprise about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about

13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about

22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about

31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about

40%, about 41%, about 42%, about 43%, about 44%, or about 45% coating (i.e. the organic material or plastic coating) by weight. In certain embodiments, the resultant solid fuel may comprise about 5% to about 45% coating (i.e. the organic material or plastic coating) by weight, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0054] In still another embodiment of any of the above method or methods, the resultant solid fuel may burn at temperature lower than that of a control organic material or plastic alone; wherein the solid fuel may produce less harmful combustion product as compared with a control organic material or plastic alone; or both. In another embodiment of any of the above method or methods, the harmful combustion product may comprise benzene, polyaromatic hydrocarbons, or both.

[0055] In another embodiment of any of the above method or methods, the resultant solid fuel may be a solid fuel as defined herein.

[0056] In another embodiment, there is provided herein a solid fuel produced by a method as described herein.

[0057] In still another embodiment, there is provided herein a method for re-using a waste organic material or plastic, said method comprising: providing a solution comprising the waste organic material or plastic in a solvent;

applying the solution to a combustible material; and evaporating the solvent, thereby re-using the waste organic material or plastic to produce a water-resistant or waterproof solid fuel as defined herein.

[0058] In another embodiment, there is provided herein a method for producing a water-resistant or waterproof fuel pellet from a combustible material comprising a biomass material or carbonaceous material and a coating comprising one or more of an organic polymer or plastic dissolved in a non-polar, low-polarity, or mid polarity solvent, the method comprising: i. Dissolving the organic polymer or plastic in a solvent to produce a solution that contains the coating material in solution;

ii. Coating the combustible material with the solution containing the coating polymer;

iii. Allowing the solvent to evaporate, or evaporating the solvent, leaving a water-resistant or waterproof coating on the biomass material or carbonaceous material.

[0059] In another embodiment of the above method, the biomass material or carbonaceous material may be made from a torrified wood pellet, a wood pellet, coal fines, or waste biomass pellets.

[0060] In another embodiment of any of the above method or methods, the organic polymer or plastic may be made from any plastic that is soluble in a non-polar, low polarity or mid polarity solvent including: Styrene, Polystyrene, styrofoam, Polylactic Acid, Acrylonitrile butadiene styrene (ABS) plastic, Acrylic or other plastic material that is soluble in an organic solvent.

[0061] In yet another embodiment of any of the above method or methods, the solvent may be one or more of the following: chloroform, acetone, methyl ethyl ketone, ethyl acetate, benzene, toluene, xylene, gasoline, or other organic solvent that will dissolve plastic..

BRIEF DESCRIPTION OF DRAWINGS

[0062] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description and accompanying drawings wherein:

[0063] Figure 1 shows heating of styrofoam in air from room temperature to 900 °C at 50 °C/min;

[0064] Figure 2 shows infrared spectra for styrofoam as a function of heating time. The mass-loss with heating is shown in Figure 1. The gas evolution occurred over a range of 400 °C to 500 °C; [0065] Figure 3 shows infrared spectrum of gases evolved during heating styrofoam in air at 50 °C/min. The spectrum was recorded at 400 °C (Figure 1 and Figure 2);

[0066] Figure 4 shows heating in air of uncoated samples: fully-torrified wood (red), partial ly-torrified wood (black) and untorrified wood pellet (blue). Heating rate was 50 °C /min to 900 °C; [0067] Figure 5 shows evolved gas infrared spectra of fully-torrified wood heated in air at 50 °C/min;

[0068] Figure 6 shows heating in air of Ont-4 heavily-coated fully-torrified wood pellets;

[0069] Figure 7 shows Gram-Schmidt plot of Styrene (blue) and heavily-coated fully-torrified wood Sample Ont-4 (red). Gram-Schmidt is a plot of the total infrared absorption of the combustion gases as a function of time; [0070] Figure 8 shows infrared spectra at 480 °C (10.5 minutes) during heating of heavily-coated fully- torrified wood Sample Ont-4 (red). The corresponding spectrum for neat styrofoam is shown in blue;

[0071] Figure 9 shows determination of styrofoam concentration via TGA analysis from the change in mass when the coating combusts: Sample Ont-2 (mid-coating partially-torrified)(red); Ont-3 (mid-coating f u lly-torrif ied)(bl ue); [0072] Figure 10 shows determination of styrofoam concentration via TGA analysis from the change in mass when the coating combusts: Sample Ont-5 (light-coatings partially-torrified)(blue); Ont-1 (light- coatings fully-torrified)(red); and

[0073] Figure 11 shows a photograph of the pellet made from Fines B as described in Example 8.

DETAILED DESCRIPTION

[0074] Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. Accordingly, the description and drawings are to be regarded as illustrative and intended for the person of skill in the art, rather than restrictive. Modifications may be made to the embodiments described here without departing from what is encompassed by the claims. [0075] Certain biomass materials, such as torrified wood, may provide a green alternative to coal. However, traditional torrified wood pellets and other such materials absorb water, causing swelling and hindering use as a fuel. Maintaining dryness complicates transport and storage, for example. As well, energy density of traditional torrified wood pellets and other such materials is typically low. For either of standard torrified wood and coal fines pellets, water exposure may create difficulties

[0076] Organic or plastic waste, such as styrofoam and other such materials, is difficult to recycle and does not burn cleanly, and so in many instances styrofoam is landfilled, creating environmental issues. Heating styrofoam in air is known to produce styrene, benzene, toluene and xylene [2] Benzene is a known carcinogen. Accordingly, burning of styrofoam for disposal thereof has typically been avoided.

[0077] As described in detail herein, methods have now been developed for preparing combustible pellets (such as torrified wood and coal fines) coated with an organic polymer or plastic (such as styrofoam), providing coated materials which are substantially waterproof or water-resistant. Resultant coated materials may provide a good fuel source which may be substantially resistant to water absorption and may provide good energy density, while also diverting waste organics/plastics (such as styrofoam) away from landfills. Also provided herein are processes for enhanced or complete combustion of styrofoam (and other such materials), converting styrofoam to C0 and water vapour through burning.

Solid Fuel Materials

[0078] In an embodiment, there is provided herein a solid fuel (i.e. a solid fuel composition) comprising a combustible material coated with an organic material or plastic. In certain embodiments, the solid-fuel may be substantially water-resistant or waterproof.

[0079] In certain embodiments, the combustible material may comprise a biomass material, a carbonaceous material, a plant-derived material, or any suitable organic or carbonaceous or carbon- containing matter which may be useful as a fuel, or any combination thereof which may be combustible. In certain embodiments, a biomass material or carbonaceous material may comprise any suitable biomass or other organic matter useful as a fuel. As will be understood, combustible materials as referred to herein may comprise generally any suitable substantially carbonaceous or carbon-containing material. Biomass materials may typically comprise plant-derived materials, such as but not limited to wood or torrified wood, charcoal, wood pellets, and ground wood. In certain embodiments, carbonaceous materials may typically comprise coal or coal fines, or fossil-based materials. The combustible materials may be provided substantially as recovered, produced, manufactured, or found in nature, or may be pre-treated by one or more processing steps such as, but not limited to, torrefaction, pelleting, or another such processing step. In certain embodiments, the combustible may comprise, for example, wood, torrified wood, another biomass material, coal, or another carbonaceous material or plant-derived or fossil-based material. By way of example, in certain embodiments, the combustible material may comprise torrified wood (such as torrified wood pellets, for example), charcoal, wood pellets, ground wood, or coal fines. In certain embodiments, the combustible material may be in the form of pellets, fines, grounds, or another structure having a size ranging from about 10 microns to about 10 cm. In certain embodiments, the combustible material may be in the form of pellets, fines, or another structure having a size ranging from about 0.01 cm to about 3 cm. In certain embodiments, the combustible material may be in the form of a standard wood pellet size, a standard briquette size, or any size therebetween, for example.

[0080] In certain embodiments, the combustible material may comprise any suitable organic or carbonaceous or carbon-containing matter useful as a fuel. In certain embodiments, the combustible material may comprise a biomass material which may comprise any suitable plant-based or plant-derived material, such as torrified wood, charcoal, wood pellets, or ground wood, for example. As will be understood, combustible materials may also include, for example, coal and/or coal fines.

[0081] In certain embodiments, the combustible material may comprise torrified wood pellets, and the torrified wood pellets may be coated with the organic material or plastic. In still another embodiment the combustible material may comprise coal fines, the coal fines may be coated with the organic material or plastic, and the solid fuel may be provided as pellets formed by pressing the coated coal fines, for example.

[0082] In certain embodiments, the organic material or plastic may comprise any suitable organic or plastic-based material. Typically, the organic material or plastic may comprise one or more polymers. In certain embodiments, the organic material or plastic may be derived from a waste material, particularly where reduction in waste (i.e. re-use) of the material is desirable. In certain embodiments, the organic material or plastic may comprise one or more hydrophobic organic-based polymers. In certain embodiments, the organic material or plastic may comprise styrofoam, Styrene, polystyrene, Acrylonitrile butadiene styrene (ABS), Poly(methyl methacrylate), Acrylic, low density polyethylene (LDPE), or another organic polymer that is soluble in a non-aqueous solvent. By way of example, in certain embodiments, the organic material or plastic may comprise styrofoam, extruded polystyrene foam, polystyrene, or Acrylonitrile butadiene styrene (ABS). [0083] In still another embodiment of any of the above solid fuel or solid fuels, the combustible material may be coated with the organic material or plastic. In certain embodiments, the coating of the combustible material may be full, or may be partial. In certain embodiments, the exterior surface of the combustible may be at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, or about 100% coated by the organic material or plastic (or coating derived therefrom). In certain embodiments, the exterior surface of the combustible may be about 20% to about 100% coated by the organic material or plastic (or coating derived therefrom), or any subrange therebetween or any value therebetween rounded to the nearest 0.1%.

[0084] In certain embodiments, the solid fuel may be coated with the organic material or plastic (or coating derived therefrom) by preparing a solution of the organic material or plastic in a solvent, applying the solution to the combustible material, and evaporating the solvent from the combustible material. In certain embodiments, the solution may comprise at least about 0.01 g/mL, at least about 0.02 g/mL, at least about 0.03 g/mL, at least about 0.04 g/mL, at least about 0.05 g/mL, at least about 0.06g/mL, at least about 0.07 g/mL, at least about 0.08 g/mL, at least about 0.09 g/mL, at least about 0.1 Og/mL, at least about 0.11 g/mL, at least about 0.12 g/mL, at least about 0.13 g/mL, at least about 0.14 g/mL, at least about 0.15 g/mL, at least about 0.16 g/mL, at least about 0.17 g/mL, at least about 0.18 g/mL, at least about 0.19 g/mL, at least about 0.20 g/mL, at least about 0.21 g/mL, at least about 0.22 g/mL, at least about 0.23 g/mL, at least about 0.24 g/mL, at least about 0.25 g/mL, at least about 0.26 g/mL, at least about 0.27 g/mL, at least about 0.28 g/mL, at least about 0.29 g/mL, or at least about 0.30 g/mL organic material or plastic. In certain embodiments, the solution may comprise about 0.01 g/mL to about 0.30 g/mL organic material or plastic, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01. In certain embodiments, the solution may comprise about 0.05 g/mL to about 0.25 g/mL, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01.

[0085] In certain embodiments, the solvent may comprise a non-polar, low-polarity, or mid polarity solvent. By way of example, in certain embodiments, the solvent may comprise one or more of chloroform, acetone, methyl ethyl ketone, ethyl acetate, benzene, toluene, xylene, gasoline, or another organic solvent that dissolves plastic. In certain embodiments, the solvent may comprise toluene. In certain embodiments, the solvent may comprise methyl ethyl ketone (MEK), acetone, or chloroform. [0086] As described in further detail below, in certain embodiments the solution may be applied to the combustible material by spraying or painting, by temporarily immersing the combustible material in the solution, by passing the combustible material through a waterfall or stream of the solution (on an assembly line, for example), or by mixing the combustible material with the solution.

[0087] In certain embodiments, the solid fuel as described herein may be substantially water-resistant or waterproof. References herein to water-resistant and/or waterproof may be understood as indicating at least some resistance toward water absorption by the combustible material of the solid fuel when the solid fuel is exposed to moisture, humidity, or liquid water, as compared with an uncoated equivalent combustible material control. The degree of water resistance may vary based (for example) on the nature and/or extent of coating, and may be selected to suit the particular application or environment to which the solid fuel may be exposed. In certain embodiments, for example, a solid fuel as described herein which is water resistant or waterproof may be resistant to substantial absorption of water for at least about 1, at least about 2, at least about 3, at least about 4, or at least about 5 minutes, or at least about 1 hour, at least about 1 day, at least about 1 week, at least about 1 month, at least about 6 months, or at least about 1 year, when immersed in water. In another embodiment, the solid fuel may be resistant to absorption of water when immersed in water for a particular duration of time selected from a range of from about 5 minutes to about 6 months, or more, or any sub-range falling therein. As described in the Examples section below, immersion testing was performed first for about 5 minutes, and then extended out to longer time periods. In immersion testing, results showed little to no absorption of water by 6 months, and some samples lasted for more than 1 year. In certain embodiments, for example, a solid fuel as described herein which is water resistant or waterproof may be resistant to crumbling or disintegration due to expansion of the combustible material from water absorption when immersed in water for at least about 1, at least about 2, at least about 3, at least about 4, or at least about 5 minutes, or at least about 1 hour, at least about 1 day, at least about 1 week, at least about 1 month, at least about 6 months, or at least about 1 year, or any time or subrange therein (i.e. the solid fuel may remain substantially structurally intact following such immersion in water).

[0088] In certain embodiments, the solid fuel may have a calorific value in MJ/Kg which is at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 11%, at least about 12%, at least about 13%, at least about 14%, at least about 15%, at least about 16%, at least about 17%, at least about 18%, at least about 19%, at least about 20%, at least about 21%, at least about 22%, at least about 23%, at least about 24%, at least about 25%, at least about 26%, at least about 27%, at least about 28%, at least about 29%, at least about 30%, at least about 31%, at least about 32%, at least about 33%, at least about 34%, at least about 35%, at least about 36%, at least about 37%, or at least about 38% greater than that of an uncoated combustible material control. In certain embodiments of any of the above solid fuel or solid fuels, the solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 50% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%. In certain embodiments, the solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 38% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0089] In certain embodiments, the solid fuel may comprise about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, or about 45% coating (i.e. the organic material or plastic coating) by weight. In certain embodiments, the solid fuel may comprise about 5% to about 45% coating (i.e. the organic material or plastic coating) by weight, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0090] In certain embodiments, the solid fuel may burn at temperature lower than that of a control organic material or plastic alone; the solid fuel may produce less harmful combustion product as compared with a control organic material or plastic alone; or both. In another embodiment, the harmful combustion product may comprise benzene, polyaromatic hydrocarbons, or both.

[0091] In another embodiment, there is provided herein a use of a solid fuel as described herein for producing energy by combustion. In yet another embodiment, there is provided herein a solid fuel as described herein for producing energy by combustion. In still another embodiment, there is provided herein a method for producing energy, comprising combusting a solid fuel as described herein.

In another embodiment, it is contemplated that where the combustible material comprises, for example, coal fines, it may be desirable in certain applications to bury or otherwise sequester the solid fuel, rather than burn the solid fuel. By burying or sequestering the solid fuel, it is contemplated that the coal fines may be sequestered and protected from water erosion by the coating, thereby sequestering and preventing fossil carbon dioxide release where desirable. Methods for Producing Water-Resistant or Waterproof Solid Fuel Compositions and Products

[0092] In yet another embodiment, there is provided herein a method for producing a water-resistant or waterproof solid fuel comprising a combustible material coated with an organic material or plastic, said method comprising: providing a solution comprising the organic material or plastic in a solvent;

applying the solution to the combustible material; and

evaporating the solvent, thereby providing the water-resistant or waterproof solid fuel comprising the combustible material coated with the organic material or plastic.

[0093] In certain embodiments, the combustible material may comprise any combustible material as described herein. In certain embodiments, for example, the combustible material may comprise wood, torrified wood, another biomass material, coal, or another carbonaceous material or plant-derived material. In certain embodiments, the combustible material may be in the form of pellets, fines, grounds, or another structure having a size ranging from about 10 microns to about 10 cm, or any subrange or value therebetween. In certain embodiments, the combustible material may be in the form of pellets, fines, or another structure having a size ranging from about 0.01cm to about 3 cm, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01 cm.

[0094] In certain embodiments, the combustible material may comprise torrified wood (such as torrified wood pellets, for example), ground wood, or coal fines. In certain embodiments, the combustible material may comprise torrified wood pellets, and the torrified wood pellets may be coated with the organic material or plastic. In still another embodiment, the combustible material may comprise coal fines, the coal fines may be coated with the organic material or plastic, and the solid fuel may be provided as pellets formed by pressing the coated coal fines.

[0095] In certain embodiments, the organic material or plastic may comprise any suitable organic material or plastic as described herein. In certain embodiments, the organic material or plastic may comprise an organic polymeric coating or plastic material derived from a waste material. In certain embodiments, for example, the organic material or plastic may comprise styrofoam, Styrene, polystyrene, Acrylonitrile butadiene styrene (ABS), Poly(methyl methacrylate), Acrylic, low density polyethylene (LDPE), or another organic polymer that is soluble in a non-aqueous solvent, or any combination thereof. By way of example, in certain embodiments, the organic material or plastic may comprise styrofoam, extruded polystyrene foam, polystyrene, or Acrylonitrile butadiene styrene (ABS).

[0096] In yet another embodiment of any of the above method or methods, the step of providing the solution may comprise dissolving the organic material or plastic in the solvent. In certain embodiments, the solvent may comprise a non-polar, low-polarity, or mid polarity solvent. By way of example, in certain embodiments, the solvent may comprise one or more of chloroform, acetone, methyl ethyl ketone, ethyl acetate, benzene, toluene, xylene, gasoline, or another organic solvent that dissolves plastic, or any combination thereof. In certain embodiments, the solvent may comprise toluene. In certain embodiments, the solvent may comprise methyl ethyl ketone (MEK), acetone, or chloroform.

[0097] In certain embodiments, the solution may comprise at least about 0.01 g/mL, at least about 0.02 g/mL, at least about 0.03 g/mL, at least about 0.04 g/mL, at least about 0.05 g/mL, at least about 0.06 g/mL, at least about 0.07 g/mL, at least about 0.08 g/mL, at least about 0.09 g/mL, at least about 0.10 g/mL, at least about 0.11 g/mL, at least about 0.12 g/mL, at least about 0.13 g/mL, at least about 0.14 g/mL, at least about 0.15 g/mL, at least about 0.16 g/mL, at least about 0.17 g/mL, at least about 0.18 g/mL, at least about 0.19 g/mL, at least about 0.20 g/mL, at least about 0.21 g/mL, at least about 0.22 g/mL, at least about 0.23 g/mL, at least about 0.24 g/mL, at least about 0.25 g/mL, at least about 0.26 g/mL, at least about 0.27 g/mL, at least about 0.28 g/mL, at least about 0.29 g/mL, or at least about 0.30 g/mL organic material or plastic. In certain embodiments, the solution may comprise about 0.01 g/mL to about 0.30 g/mL organic material or plastic, or any subrange therebetween, or any value

therebetween rounded to the nearest 0.01. In certain embodiments, the solution may comprise about 0.05 g/mL to about 0.25 g/mL, or any subrange therebetween, or any value therebetween rounded to the nearest 0.01.

[0098] In still another embodiment of any of the above solid fuel or solid fuels, the combustible material may be coated with the organic material or plastic. In certain embodiments, the coating of the combustible material may be full, or may be partial. In certain embodiments, the exterior surface of the combustible may be at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, or about 100% coated by the organic material or plastic (or coating derived therefrom). In certain embodiments, the exterior surface of the combustible may be about 20% to about 100% coated by the organic material or plastic (or coating derived therefrom), or any subrange therebetween or any value therebetween rounded to the nearest 0.1%.

[0099] In another embodiment, the step of applying the solution to the combustible material may comprise spraying or painting the solution onto the combustible material; temporarily immersing the combustible material in the solution; passing the combustible material through a waterfall or stream of the solution (on an assembly line, for example); or mixing the combustible material with the solution.

[0100] In certain embodiments, the solid fuel as described herein may be substantially water-resistant or waterproof. References herein to water-resistant and/or waterproof may be understood as indicating at least some resistance toward water absorption by the combustible material of the solid fuel when the solid fuel is exposed to moisture, humidity, or liquid water, as compared with an uncoated equivalent combustible material control. The degree of water resistance may vary based (for example) on the nature and/or extent of coating, and may be selected to suit the particular application or environment to which the solid fuel may be exposed. In certain embodiments, for example, a solid fuel as described herein which is water resistant or waterproof may be resistant to substantial absorption of water for at least about 1, at least about 2, at least about 3, at least about 4, or at least about 5 minutes, or at least about 1 hour, at least about 1 day, at least about 1 week, at least about 1 month, at least about 6 months, or at least about 1 year, when immersed in water. In another embodiment, the solid fuel may be resistant to absorption of water when immersed in water for a particular duration of time selected from a range of from about 5 minutes to about 6 months, or more, or any sub-range falling therein. As described in the Examples section below, immersion testing was performed first for about 5 minutes, and then extended out to longer time periods. In immersion testing, results showed little to no absorption of water by 6 months, and some samples lasted for more than 1 year. In certain embodiments, for example, a solid fuel as described herein which is water resistant or waterproof may be resistant to crumbling or disintegration due to expansion of the combustible material from water absorption when immersed in water for at least about 1, at least about 2, at least about 3, at least about 4, or at least about 5 minutes, or at least about 1 hour, at least about 1 day, at least about 1 week, at least about 1 month, at least about 6 months, or at least about 1 year, or any time or subrange therein (i.e. the solid fuel may remain substantially structurally intact following such immersion in water).

[0101] In certain embodiments, the resultant solid fuel may have a calorific value in MJ/Kg which is at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 11%, at least about 12%, at least about 13%, at least about 14%, at least about 15%, at least about 16%, at least about 17%, at least about 18%, at least about 19%, at least about 20%, at least about 21%, at least about 22%, at least about 23%, at least about 24%, at least about 25%, at least about 26%, at least about 27%, at least about 28%, at least about 29%, at least about 30%, at least about 31%, at least about 32%, at least about 33%, at least about 34%, at least about 35%, at least about 36%, at least about 37%, or at least about 38% greater than that of an uncoated combustible material control. In certain embodiments, the resultant solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 50% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%. In certain embodiments, the resultant solid fuel may have a calorific value in MJ/Kg which is between about 5% and about 38% greater than that of an uncoated combustible material control, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0102] In yet another embodiment, the resultant solid fuel may comprise about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, or about 45% coating (i.e. the organic material or plastic coating) by weight. In certain embodiments, the resultant solid fuel may comprise about 5% to about 45% coating (i.e. the organic material or plastic coating) by weight, or any subrange therebetween, or any value therebetween rounded to the nearest 0.1%.

[0103] In still another embodiment, the resultant solid fuel may burn at temperature lower than that of a control organic material or plastic alone; wherein the solid fuel may produce less harmful combustion product as compared with a control organic material or plastic alone; or both. In another embodiment, the harmful combustion product may comprise benzene, polyaromatic hydrocarbons, or both.

[0104] In another embodiment, there is provided herein a solid fuel produced by a method as described herein.

[0105] In still another embodiment, there is provided herein a method for re-using a waste organic material or plastic, said method comprising: providing a solution comprising the waste organic material or plastic in a solvent;

applying the solution to a combustible material; and evaporating the solvent,

thereby re-using the waste organic material or plastic to produce a water-resistant or waterproof solid fuel as defined herein.

[0106] In another embodiment, there is provided herein a method for producing a water-resistant or waterproof fuel pellet from a combustible comprising a biomass material or carbonaceous material and a coating comprising one or more of an organic polymer or plastic dissolved in a non-polar, low-polarity, or mid polarity solvent, the method comprising: i. Dissolving the organic polymer or plastic in a solvent to produce a solution that contains the coating material in solution.

ii. Coating the combustible material or pellet with the solution containing the coating polymer. iii. Allowing the solvent to evaporate, or evaporating the solvent, leaving a water-resistant or waterproof coating on the biomass material or carbonaceous material.

[0107] In another embodiment, the biomass material or carbonaceous material may be made from a torrified wood pellet, a wood pellet, coal fines, or waste biomass pellets.

[0108] In another embodiment, the organic polymer or plastic may be made from any plastic that is soluble in a non-polar, low polarity or mid polarity solvent including: Styrene, Polystyrene, styrofoam, Polylactic Acid, Acrylonitrile butadiene styrene (ABS) plastic, Acrylic or other plastic material that is soluble in an organic solvent.

In yet another embodiment, the solvent may be one or more of the following: chloroform, acetone, methyl ethyl ketone, ethyl acetate, benzene, toluene, xylene, gasoline, or other organic solvent that will dissolve plastic.

[0109] In an embodiment, methods are provided herein for making combustible pellets, such as torrified wood pellets, substantially water-resistant and/or waterproof (or for increasing the water-resistance of such combustible materials). In another embodiment, methods are provided herein providing for the safe disposal of styrofoam and other such plastics or organics. As detailed herein, using a waste water- repellent material such as styrofoam as a feedstock for the production of water-resistant and/or waterproof combustible pellets, such as torrified wood pellets, may reduce or overcome the moisture problems associated with wood pellets and other such pellets, as well as the waste disposal problems that styrofoam and other such plastics/organics present. By combining combustible pellets or other such combustible matierials (such as torrified wood pellets, for example) and styrofoam (or other such organics/plastics), the inventors have developed products which may feature higher energy density and/or burning at low temperatures without (or with reduced) emission of carcinogens such as polyaromatic hydrocarbons and/or benzene. [0110] As will be understood, a number of aspects, embodiments, and examples are described herein, which may be exploited individually or in combination.

[0111] In an embodiment, there is provided herein a method for producing a water-resistant or waterproof fuel pellet from input materials comprising torrified wood pellets and one or more of: an organic polymeric coating or plastic material derived from waste materials such as: styrofoam, Styrene, polystyrene, Acrylonitrile butadiene styrene (ABS), Poly(methyl methacrylate), Acrylic, low density polyethylene (LDPE), or any organic polymer that is soluble in a non-aqueous solvent. Herein, the term organic is used in the sense of organic chemistry.

[0112] In certain embodiments, methods as described herein may be used for enhancing combustion of styrofoam (and/or other such organic materials or plastics), by preparing a solid fuel as described herein and burning said solid fuel, converting styrofoam to C0 with reduced emission of polyaromatic hydrocarbons and/or benzene.

EXAMPLES

[0113] The present inventors hypothesized that a good water resistant or waterproof coating for torrified wood pellets and other such combustible materials would have sufficiently low ash content, low moisture content, and high heating value. As further described herein, the present inventors developed coatings which may be derived from an input of waste materials which are currently difficult to recycle or safely dispose.

[0114] The melting point of styrofoam is 240 °C while the decomposition temperature is 300°C. The auto ignition temperature of the vapours given off from heated styrene is 427 °C [1] As indicated above, heating styrofoam in air is known to produce styrene, benzene, toluene and xylene [2], and benzene is a known carcinogen. [0115] Properties of waste styrofoam were measured during heating in air at a rate of 50 °C/min to 900 °C. The mass-loss and heat flow were measured with a Mettler TGA DSC1 Thermo-gravimetric analyzer. Infrared spectra of the combustion gases were determined using a heated gas cell in a Thermo 6700 FTIR. The data were collected using Thermo's Omnic Series software to acquire the infrared spectra of the evolved combustion gases as a function of time. Results are shown in Figure 1 and in Figure 2.

[0116] Pleating styrofoam in air resulted in an evaporative mass-loss with an onset of 406 °C. The heat flow curve (red insert in Figure 1) shows two endothermic peaks indicating that two components with differing boiling points were evolved. The first endothermic maximum was at 446 °C while the latter was at 469 °C. After the second evaporative peak, the heat flow became exothermic indicating the material was combusting. The temperature for the exothermic peak observed in Figure 1 is higher than the value for auto ignition of 440 °C [1] because of the rapid heating rate of the sample.

[0117] Figure 3 shows signatures of styrene and aromatic ring compounds that are produced from the low-temperature combustion of styrofoam (400 °C). These signatures indicate the presence of polyaromatic hydrocarbons and benzene. These products are observed at temperatures as high as 950 °C [3] Thus, results suggest that combustion of styrofoam-only products typically should be done at temperatures above 950 °C to ensure no release of polyaromatic hydrocarbons and benzene. Ability to combust styrofoam at lower temperature without substantial release of polyaromatic hydrocarbons and benzene would be desirable.

Table 1 - Calorific value and proximate analysis of coated partially torrified wood pellets and fully torrlfed wood pellets.

Example 1.

[0118] Samples of partially torrified wood pellets obtained from Airex Energy were analyzed for calorific value as per ASTM D5864 and proximate analysis as per ASTM E1171; these analyses were to establish a reference to which coated samples could be compared; this reference sample was labeled as Sample Ont- 7. A sample of 1.125 grams of waste styrofoam was dissolved in 20 ml of Toluene making solution A. The partially torrified wood pellets labeled Ont-7 were then coated with a polystyrene coating by dipping the pellets into solution A. The dipped samples were removed from solution A and allowed to dry: the toluene solvent evaporated leaving a 'light' polystyrene coating on the partially torrified wood pellets - these coated samples were labeled Ont-5. The Calorific Value for samples Ont-5 was determined as per ASTM D5865; the proximate analysis was done using ASTM E1171. Calorific values and proximate analyses are shown in Table 1 in the rows labeled Ont-7 and Ont-5.

[0119] To test for water resistance, an uncoated pellet and a coated pellet were immersed in water first for 5 minutes. The uncoated pellet labelled Ont-7 crumbled and fell apart due to expansion of the biomass from water absorption. The polystyrene coated pellet labeled Ont-5 did not change when immersed in water for 5 minutes indicating that the pellet was water resistant/waterproof. Water immersion testing was then extended out to longer time periods for the Ont-5 coated pellets described in this example. In immersion testing, results showed little to no absorption of water by 6 months for the Ont-5 coated pellets. [0120] The thermal behaviour of coated biofuel samples was measured during heating in air at a rate of 50 °C/min from room temperature to 900 °C. The mass-loss and heat flow were measured. The Infrared spectra of the combustion gas was determined using a heated gas cell in a Thermo 6700 FTIR. The data were collected using Thermo's Omnic Series software to acquire the infrared spectra of the evolved gases as a function of time.

Example 2.

[0121] A sample of 2.25 grams of waste styrofoam was dissolved in 20 ml of Toluene making solution B. The partially torrified wood pellets labeled Ont-7 were then coated with a polystyrene coating by dipping the pellets into solution B. The dipped samples were removed from solution B and allowed to dry: the toluene solvent evaporated leaving a 'mid-level' polystyrene coating on the partially torrified wood pellets -these coated samples were labeled Ont-2. The Calorific Value was determined as per ASTM D5865 while the proximate analysis was determined using ASTM E1171. The calorific value and the proximate analysis are shown in Table 1 in the row labeled Ont-2.

[0122] The coated pellet labeled Ont-2 was immersed in water for 5 minutes. Unlike the uncoated pellet which crumbled, there was no change in the coated pellet confirming the water-resistant/waterproof nature of the coated pellet. Water immersion testing was also extended out to longer time periods for the coated pellets described in this example. In immersion testing, results showed little to no absorption of water by 6 months, and some samples lasted for more than 1 year.

Example 3.

[0123] Samples of fully-torrified wood pellets obtained from Airex Energy were analyzed for calorific value as per ASTM D5864 and proximate analysis as per ASTM E1171; these analyses were to establish a reference to which coated samples could be compared; this reference sample was labeled as Sample Ont- 6. A sample of 1.125 grams of waste styrofoam was dissolved in 20 ml of Toluene making solution A. The torrified wood pellets labeled Ont-6 were then coated with a polystyrene coating by dipping the pellets into solution A. The dipped samples were removed from solution A and allowed to dry: the toluene solvent evaporated leaving a 'light' polystyrene coating on the fully torrified wood pellets - these coated samples were labeled Ont-1. The Calorific Value was determined as per ASTM D5865 while the proximate analysis was determined using ASTM E1171. The calorific value and the proximate analysis are shown in Table 1 in the row labeled Ont-1. [0124] The coated pellet labeled Ont-1 was immersed in water for 5 minutes. Unlike the uncoated fully torrified pellet which crumbled, there was no change in the coated pellet confirming the coated pellet is water resistant/waterproof. Water immersion testing was also extended out to longer time periods for the coated pellets described in this example. In immersion testing, results showed little to no absorption of water by 6 months, and some samples lasted for more than 1 year.

Example 4.

[0125] A sample of 2.25 grams of waste styrofoam was dissolved in 20 ml of Toluene making solution B. The fully-torrified wood pellets labeled Ont-6 were then coated with a polystyrene coating by dipping the pellets into solution B. The dipped samples were removed from solution B and allowed to dry: the toluene solvent evaporated leaving a 'mid-level' polystyrene coating on the fully-torrified wood pellets - these coated samples were labeled Ont-3. The Calorific Value was determined as per ASTM D5865 while the proximate analysis was determined using ASTM E1171. The calorific value and the proximate analysis are shown in Table 1 in the row labeled Ont-3.

[0126] The coated pellet labeled Ont-3 was immersed in water for 5 minutes. Unlike the uncoated fully- torrified pellet which crumbled, there was no change in the coated pellet confirming the coated pellet was waterproof/water-resistant. Water immersion testing was also extended out to longer time periods for the coated pellets described in this example. In immersion testing, results showed little to no absorption of water by 6 months, and some samples lasted for more than 1 year.

Example 5. [0127] A sample of 4.5 grams of waste styrofoam was dissolved in 20 ml of Toluene making solution C.

The fully-torrified wood pellets labeled Ont-6 were then coated with a polystyrene coating by dipping the pellets into solution C. The dipped samples were removed from solution C and allowed to dry: the toluene solvent evaporated leaving a 'heavy' polystyrene coating on the fully torrified wood pellets -these coated samples were labeled Ont-4. The Calorific Value was determined as per ASTM D5865 while the proximate analysis was determined using ASTM E1171; the results are shown in Table 1 in the row labelled Ont-4.

[0128] Figure 4 shows the mass-loss as a function of temperature for samples of partially-torrified wood, (Ont-7), and torrified wood (Ont-6) obtained from Airex Energy; neither of these samples were coated, these are the reference base materials for the coating experiments. Figure 4 shows a mass-loss at approximately 100 °C, which is due to adsorbed moisture. The fully-torrified pellets had an onset of combustion mass-loss at 342 °C and the partially-torrified pellets onset of mass-loss occurred at 314 °C. The mass-loss temperature dependence looks similar for partially-torrified pellets and wood pellets.

[0129] Evolved gas spectra obtained during heating of fully-torrified wood are shown in Figure 5; similar spectra were observed for partially-torrified wood. From the spectra, only two gases were identified: water and carbon dioxide. During the initial stage of combustion between 340 °C and 450 °C, the infrared spectra show that some carbon monoxide is evolved because of smoldering prior to ignition.

[0130] Combustion products and behaviour for styrofoam-coated biomass pellets were identified and compared with the products and behaviour obtained during combustion of neat styrofoam. The combustion behaviour of the heavily-coated fully-torrified wood pellet sample Ont-4 was measured by heating in air with a flow rate of 50 ml/min and a heating rate of 50 °C/min in a Mettler TGA/DSC1. The mass-loss and heat flow are displayed graphically in Figure 6. The first mass-loss at about 100 °C is from moisture in the pellet. The onset of mass-loss at 324 °C and the corresponding increase in exothermic heat flow indicates the pellet is combusting. The heat flow dip at 446°C is attributed to the evaporation of styrene decomposition products below their auto-ignition temperature.

[0131] The combustion behaviour of the coated pellet can be quantified with a measure of the total evolved gas obtained from the integrated infrared absorption. The total infrared spectral intensity as a function of time provides a measure of the infrared-active gaseous products being evolved as the sample is heated. The plot of Infrared Intensity versus Time is known as a Gram-Schmidt plot.

[0132] Representative Gram-Schmidt plots are shown in Figure 7 for neat styrofoam and heavily-coated fully-torrified wood samples (Ont-4). The gas emissions start earlier for the coated sample than for the styrofoam sample. Earlier emissions are expected when wood is involved because the onset of mass-loss begins at a lower temperature for the fully-torrified wood than for styrofoam: 340 °C (Figure 4) versus 405 °C (Figure 2), respectively. This lower temperature for the onset of gas emission is indicative of a lower temperature for the onset of combustion. Reducing the combustion temperature for the coated pellets is desirable because it means the styrofoam in the coating will start combustion at a lower temperature than it otherwise would without the biomass at the core of the pellet.

[0133] An example of an infrared spectrum of the gases evolved during heating sample Ont-4 is shown in Figure 8. The graph also includes the corresponding styrofoam spectrum for comparison. Major peaks from combustion of the biofuel include carbon dioxide (large peak at 2300-2400 cm ¹ ), water (3500 cm ¹ and 4000 cm ¹ ), carbon monoxide (two rounded peaks to the right of the C0 ₂ peak and above 2000 cm ¹ ). The doublet peak at about 3100 cm ¹ is due to aromatic C-H stretching. The peak at 1500cm ¹ is due to aromatic C=C bending. The strong peaks below 1000 cm ¹ indicate aromatic C-H bending of benzene rings.

[0134] Figure 8 shows the FTIR spectra of coated torrified wood (red) at about 480°C, which can be compared with the spectrum of styrofoam. At this temperature, the combustion products of the coated biofuel sample have none of the signatures associated with styrofoam at the same temperature; all that is seen are the typical evolved gases for torrified wood. Thus, the composite pellet made of a biomass pellet and a styrofoam coating burns at lower temperatures and without the harmful combustion products, such as polyaromatic hydrocarbons and benzene, when compared with pellets made from neat styrofoam. Example 6.

[0135] Samples of partial ly-torrified wood pellets and fully-torrified wood pellets coated with the waste styrofoam using the coating processes described above were heated in a Nitrogen atmosphere to determine the amount of polystyrene on the wood pellets using a Mettler TGA/DSC1. The mass-loss and heat flow were measured as a function of temperature. The flow rate of the Nitrogen was 50 ml/min and the heating rate was 10 °C/min. The results for samples Ont-2 and Ont-3 are shown in Figure 9. The mass- loss maximum given by the first derivative of mass-loss at 439 °C is indicative of the decomposition and volatilization of the styrofoam coating on the torrified wood. The mass-loss step change around 439 °C is because of the loss of the polystyrene coating; this change in mass serves as a measure of the fractional amount of polystyrene on the sample. Figure 10 shows the mass-loss of samples Ont-1 and Ont-5. From these and similar thermogravimetric analyses the mass-fractions of the coating on the pellets were determined. The results are summarized in Table 2.

Table 2 - Mass Fraction of styrofoam on torrified wood pellets.

Example 7.

[0136] Samples of waste ABS were dissolved in several solvents to determine the effectiveness of using different solvents. The solvents tested were methyl ethyl ketone (MEK), acetone and chloroform. Two different concentrations of ABS in the solvent were tested: 2.5 grams of ABS in 20 ml of solvent and 5 grams of ABS in 20 ml of solvent. Torrified wood pellets obtained from Airex Energy were dipped into the ABS solutions, then removed from the solutions and allowed to dry; the solvent evaporated leaving a coating on the pellet. The pellets were exposed to moisture and no effect was observed. Thus, the pellets were found to be water resistant/waterproof. Table 3 shows the results of Proximate analyses for these ABS coated pellets.

Table 3 - Proximate analyses of coated torrified pellets where the coating is made from ABS plastic dissolved in various solvents

Example 8. [0137] Samples of waste styrofoam were dissolved in toluene solvent to determine the effectiveness of coating coal fines. The mixtures of styrofoam to toluene were as follows: Condition A: 1.125g styrofoam in 20ml of toluene, condition B: 2.25g styrofoam in 20ml of toluene and condition C: 4.5g styrofoam in 20ml of toluene. The dissolution of the styrofoam in toluene resulted in a polystyrene solution in toluene. Coal fines were then coated with the styrofoam solutions conditions A, B, and C giving coated fines that were then pressed into hard pellets. The coated fines labeled Fines A, Fines B and Fines C were then tested for the proximate analysis. The proximate analysis and H HV are listed in Table 4. Table 4:

[0138] The coated fines were pressed into hard pellets and were then subjected to immersion in water for five minutes. There was no observable change in the pellets after immersion demonstrating that the coal fine pellets were durable and waterproof/water-resistant. A photograph of the pellet made from Fines B is shown in Figure 11. Water immersion testing was also extended out to longer time periods for the coated pellets described in this example. In immersion testing, results showed little to no absorption of water by 6 months, and some samples lasted for more than 1 year.

Example 9.

[0139] Samples of ground wood were coated with styrofoam solutions made as described in Example 8. The coated ground wood samples were labeled Wood A, Wood B and Wood C respectively. The material was pressed into hard pellets using a standard die press with a pressure of 70 MPa. The pellets were hard and non-friable. The proximate analysis and higher heating value of the material is stated in Table 5.

Table 5:

[0140] As described in the preceding examples, a variety of solid fuels comprising a combustible material coated with an organic material or plastic were prepared and tested, showing good water-resistant or waterproof properties as well as other desirable characteristics. By way of example, samples Ont-5, Ont- 2, Ont-1, Ont-3, and Fines A, Fines B, and Fines C were all tested for immersion in water out to 6 months, and all showed good results. Further, samples Ont-2, Ont-1, Ont-3, and Fines A, Fines B, and Fines C each demonstrated at least some pellets that were still intact even at the 1-year mark under the conditions tested.

[0141] While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the claims are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.

[0142] It will be understood that all references hereinabove to ranges of values, or values selected from between a lower limit and an upper limit, or values above a lower limit, or values below an upper limit, are intended to also encompass and describe narrower embodiments, such as any sub-ranges or subsets of values falling within the larger ranges, or falling between any two values provided herein, and any particular integer value, or value rounded to the nearest 0.1, which is found within the larger ranges which are defined.

[0143] Without wishing to be bound by theory, an interpretation of the underlying chemistry is provided to illustrate what may be mechanistic model of present technology. However, it will be understood that the invention may still be practiced regardless of whether the particulars of the following interpretation are correct. It is contemplated that the hydrophobic water-repellent styrofoam may provide water- resistance to the composite pellet when it forms a coating on the combustible material. The coating may or may not completely cover the surface of the pellet, and it is contemplated that the coated pellet would still have improved resistance to wetting. The coating may be thin enough so that when heated to the ignition temperature of the combustible material the thermal decomposition products of the combustible material may be released into the surrounding air where they may react with combustible material and styrofoam. These thermal decomposition products may include free radicals that may take part in branching chain reactions, for example. Free radicals are highly reactive chemicals that may destroy otherwise stable chemicals by re-distributing electrons used in chemical bonds and may produce more free radicals. The combustion of combustible material may produce free radicals near to the styrofoam coating. These free radicals may react to destroy the styrofoam at the temperatures where the combustible material radicals are formed, which is at a lower temperature than where styrofoam free radicals are formed. Thus, the styrofoam coating may undergo combustion at lower temperatures than does neat styrofoam. When neat styrofoam is burned the temperature of the reaction melts the styrofoam, which lowers the reaction temperature and an insulating char may form on the surface. The result is the styrofoam may form into pools of liquid with small ratios of 'surface-area to volume' and the liquid smoulders and smokes. But when burning styrofoam as a thin coating on combustible material, the styrofoam may melt into the biomass and may not pool. Because the coating is thin, the styrofoam in the coating may maintain high 'surface-area to volume' ratios because the coating may be mechanically supported by the combustible material at the core of the composite pellet. Thus, the combination of a thin styrofoam coating on a combustible pellet may provide an environment where styrofoam may not pool and where radicals from thermal decomposition of the combustible material may facilitate the thermal decomposition of the styrofoam. The coated pellets may burn hotter and cleaner than uncoated combustible material pellets because the energy density of styrofoam is greater than the energy density of biomass. Likewise, when coated on the combustible material, the styrofoam may also burn cleaner than isolated styrofoam since pooling may be prevented. In this way, coated pellets may be made that may be water resistant or waterproof and may burn hotter and cleaner at lower temperature.

[0144] One or more illustrative embodiments have been described by way of example. It will be understood to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims.

REFERENCES

1. Inchem Styrene. Inchem. [Online] http://www.inchem.org/documents/icsc/icsc/eicsl043.htm.

2. P. Gallaghe, Handbook of Thermal Analysis and Calorimetry, Amsterdam : Elsevier Science B.V., 1998. 3. R.A. Hawley-Fedder, M.L. Parsons, Products obtained during combustion of polymers under simulated incinerator conditions. J. Chromatography, 315 (1984) 201-210