GB2315278A - Fuel briquette - Google Patents

Abstract

A solid fuel carbonaceous briquette includes an ignition enhancer, for example potassium nitrate, potassium chlorate and/or potassium permanganate. The briquette may be combined with a further briquette containing no enhancer. The carbonaceous material may be coal, coke or charcoal.

Description

IMPROVEMENTS IN OR RELATING TO SOLID FUELS This invention concerns improvements in or relating to solid fuels suitable for use domestically.

In particular, but not exclusively, the present invention has reference to solid fuels in the form of briquettes for use in domestic appliances and barbecues.

It is of course well known that solid fuels have for centuries been important as a source of heat and for cooking, and indeed they remain so in many countries although the magnitude of their consumption has declined in favour of higher amenity fuels such as oil and gas.

The main consumer-perceived disadvantages of solid fuels are poor handleability in terms of weight and grime, and slow ignitability. These adverse feature are particularly associated with coal-based fuels which, paradoxically, have the highest heat value per unit weight and per unit volume of the range of solid fuels available. Manufactured briquettes form an important segment of the market within the range of coal-based fuels.

Increasingly for the heating market, consumers purchase solid fuels not as a primary heat source but to provide supplementary heating, and accordingly the demand is for higher amenity.

An object of the present invention is therefore to provide a solid fuel which possesses relatively higher amenity in terms of both its ignition properties and cleanliness in its handleability when compared with conventional solid fuels currently available, whilst retaining a high calorific value.

According to a first aspect of the invention, there is provided a solid fuel comprising carbonaceous briquettes which include an ignition enhancer as a component thereof.

The ignition enhancer is selected to confer on the briquette a high but safe ignitability thereby enhancing the amenity of the briquette for the consumer by facilitating the fire lighting task.

Preferably, the ignition enhancer is an oxidising agent which may be for example potassium chlorate or potassium nitrate, or potassium permanganate or a combination thereof.

The carbonaceous briquette may be manufactured in any convenient manner and may include the bonding together of a particulate carbonaceous component such as coal and/or petroleum coke and/or charcoal optionally with a binder such for example as acidified molasses, starch, lignosulphate, resin bitumen or coal-tar pitch. The briquettes may be pressed or extruded or formed in any appropriate manner to give the desired shape and consistency.

It is desirable to select high rank coals, especially those having low smoke emissions such as anthracite and advantageously the particle size of the carbonaceous component will be below 3 mm.

The ignition enhancer is preferably in pulverulent form and can conveniently be mixed with the carbonaceous component for briquetting. In the case where a binder is used the enhancer is added before the addition of the binder. The ignition enhancer may be used in amounts of up to 30% by weight. Potassium chlorate may be included in the range of 7-15% by weight and potassium nitrate in the range 15-25% by weight of the total weight of the briquetting feedstock.

According to a second aspect of the invention, there is provided a solid fuel mix including a first component comprising the solid fuel of the first aspect and a second component comprising a further solid fuel.

The second component may be a carbonaceous briquette with no ignition enhancer or it may be lump coal or a combination thereof.

Advantageously, the second component of the solid fuel mix is provided with a readily ignitable coating which may be applied by immersion of the component in molten paraffin wax for a set period. By way of example, the second component may be coal briquettes and such briguettes of nominal 80g weight and at 2500C can be immersed for 20 seconds and after draining, possess a wax coating representing between 2-3% of the total weight of the briquette.

Modern roll-press briquetting processes lend themselves to the wax coating operation referred to above since such processes involve the heating or curing of the briquettes soon after pressing in order to improve impact strength and weather resistance. The purpose of a wax coating on the second component is in use, within a fire bed of the solid fuel mix, to give a flame to the fire bed soon after ignition. Whilst the early production of a flame is not particularly beneficial in a combustion sense, its presence inspires consumer confidence that the fire bed has actually been lit. However, the generation of the flame does provide a useful continuum between the ignition of the first component, namely the carbonaceous briquettes incorporating the ignition enhancer, and the flame break-through in the fire bed caused by ignition of the second component per se.

It is to be understood that the first component may also be provided with a readily ignitable coating in a similar manner as for the second component.

The first component may comprise up to 50% by weight of the total mix weight and the percentage inclusion of said first component may advantageously lie in the range 10 to 30% by weight.

According to a third aspect of the invention there is provided a solid fuel of the first aspect of the invention contained within a combustible packaging.

According to a fourth aspect of the invention there is provided a solid fuel mix of the second aspect of the invention contained within a combustible packaging.

Preferably the first component of the solid fuel mix is placed at the bottom of the packaging.

The combustible packaging may be in the form of a carton or cassette produced from paper or cardboard or any suitable material readily burnable in a safe and easy manner.

The provision of the packaging enhances the amenity of the solid fuel or the solid fuel mix since the consumer does not have to handle the fuel as such. In practice, the whole packaging is placed for example on a fire grate and ignited. The packaging may be provided with a lighting tab or touch-paper or the like and may have a handle to facilitate carriage.

The solid fuel and the solid fuel mix of the present invention may be used on conventional open-fires normally to provide only space heating, but also on occasion hot water. In comparison with other fuels of a similar type, the present invention affords ease and swiftness of ignition with a relatively short period for the establishment of an attractive fire and a heat output meeting a minimum standard. The encapsulation of the solid fuel or the solid fuel mix within the packaging gives the added advantage of cleanliness, ease of handling and convenience of ignition.

The solid fuel of the first aspect may also be used for barbecues. In comparison with other fuels they are quicker to light and quicker to attain a standard heat output. The use of this solid fuel in the packaging brings the added advantage of cleanliness and ease of handling.

By way of example only, various embodiments of the present invention are described below with reference to the Examples.

Example I A solid fuel according to the first aspect of the invention was produced in the form of a briquette from a blend of coal, petroleum coke and charcoal comprising 90% by weight and 10% potassium chlorate with a binder of starch added at 1% and acidified molasses (molasses acidified with phosphoric acid) added at 10% to the above mixture. The resulting briquette was lit on a flat test tray and was glowing red after 3 minutes.

Example II A solid fuel according to the first aspect of the invention was produced in the form of a briquette from a blend of coal, petroleum coke and charcoal comprising 85% by weight and 15% potassium chlorate with a binder of starch added at 1% and acidified molasses (molasses acidified with phosphoric acid) added at 10% to the above mixture. The resulting briquette was lit on a flat test tray with an increased flame in comparison to Example and was glowing red after 2 minutes.

Example III A solid fuel according to the first aspect of the invention was made in the form of briquettes from 81% by weight of charcoal, 19% by weight of potassium nitrate with 2% starch binder added to the above mixture.

A solid fuel mix according to the second aspect of the invention was made and comprised the above described solid fuel as the first component together with a second component in the form of briquettes produced from a mixture of anthracite, petroleum coke and bituminous coal bound with starch and acidified molasses.

A solid fuel mix according to the fourth aspect of the invention was placed in packaging with the 11% of the first component and 89% of the second component, the packaging comprising an inner covering of paper and an outer covering of cardboard.

The packaged solid fuel mix was placed on a conventional open fire grate and ignited. The fire was spreading well after 8 minutes and fully established after 12 minutes.

Example IV A solid fuel according to the first aspect of the invention was made in the form of briquettes from 90% by weight of charcoal, 10% by weight of potassium chlorate with 2% starch binder added to the above mixture.

A solid fuel mix was produced as described in Example III above.

A solid fuel mix according to the fourth aspect of the invention was placed in packaging with the 18% of the first component and 82% of the second component, the packaging comprising an inner covering of paper and an outer covering of cardboard.

The packaged solid fuel mix was placed on a conventional open fire grate and ignited. After a period of 3 minutes the solid fuel including the ignition enhancer could be seen glowing red hot and a well established fire was achieved in 15 minutes.

ExamPle V The solid fuel of this example was produced in a similar fashion as that of Example III but with 7.5% potassium chlorate and the solid fuel mix had 16% by weight of the first component and 84% by weight of the second component.

The solid fuel mix was packaged as in previous examples and placed on an open fire grate where it was lit. A fully established fire was achieved in 14 minutes.

Example VI The solid fuel of this example was produced in a similar fashion as that of Example III but with 9% potassium chlorate and the solid fuel mix had 18% by weight of the first component and 82% by weight of the second component.

The solid fuel mix was packaged as in previous examples and placed on an open fire grate where it was lit. A fully established fire was achieved in 15 minutes.

By way of comparison, briquettes produced as the second component in the solid fuel mix comprising a combination of anthracite, petroleum coke and bituminous coal bound with starch and acidified molasses were provided with firelighters representing 5% by weight of the total mixture, were packaged as described in Example III above and lit. After 25 minutes the fire was poorly established without occupying the whole grate.

The present invention thus provides a significant improvement over conventional solid fuel types with enhanced ignition properties and high amenity.

Claims (20)

1. A solid fuel comprising carbonaceous briquettes which include an ignition enhancer as a component thereof.

2. A solid fuel according to Claim 1 in which the ignition enhancer is an oxidising agent.

3. A solid fuel according to Claim 1 or 2 in which the ignition enhancer comprises up to 30% by weight of the solid fuel.

4. A solid fuel according to any one of the preceding claims in which the ignition enhancer is potassium nitrate.

5. A solid fuel according to Claim 4 in which 15% to 25% potassium nitrate is included in the solid fuel.

6. A solid fuel according to Claim 1, 2 or 3 in which the ignition enhancer is potassium chlorate.

7. A solid fuel according to Claim 6 in which up to 20% by weight of potassium chlorate is included in the solid fuel.

8. A solid fuel according to Claim 7 in which 7% to 15% by weight of potassium chlorate is included in the solid fuel.

9. A solid fuel according to Claim 1, 2 or 3 in which the ignition enhancer is potassium permanganate.

10. A solid fuel according to Claim 1, 2 or 3 in which the ignition enhancer is a combination of two or more of potassium nitrate, potassium chlorate and potassiun permanganate.

11. A solid fuel substantially as hereinbefore described with reference to the Examples.

12. A solid fuel mix including a first component comprising a solid fuel as claimed in any one of the preceding claims together with a second component comprising a further solid fuel.

13. A solid fuel mix according to Claim 12 in which the second component is a carbonaceous briquette with no ignition enhancer or lump coal or a combination thereof.

14. A solid fuel mix according to Claim 12 or 13 in which the first component comprises up to 50% by weight of the total mix weight.

15. A solid fuel mix according to Claim 14 in which the inclusion of the first component lies in the range 10 to 30% by weight of total mix weight.

16. A solid fuel mix according to any one of the preceding claims 12 to 15 in which the second component is provided with a readily ignitable coating.

17. A solid fuel mix according to Claim 16 in which the readily ignitable coating is paraffin wax.

18. A solid fuel mix substantially as hereinbefore described with reference to the Examples.

19. A solid fuel or a solid fuel mix according to any one of the preceding claims and contained within a combustible packaging.

20. A solid fuel or a solid fuel mix according to Claim 19 and substantially as hereinbefore described with reference to the Examples.