FUEL

Abstract

The invention relates to a fuel having an additive for increasing the calorific value, wherein the additive hardens and the handling of the fuel is thereby improved.

Description

The invention relates to a fuel and a method for producing this fuel.

Fossil fuels in solid form and fuels from biomass have been known for a long time. These fuels are needed in many branches of industry for various applications but are mainly used for generating electrical energy or heat in power plants or for heating purpose in private areas.

Due to the increasing shortage and the rising costs for fuels, attempts are being made to increase the calorific value of the fuels by means of additives.

It is known from U.S. Pat. No. 4,443,227 to treat charcoal with a fatty-acid-based additive and WO 96/14372 discloses a fuel made of organic materials which also has a fatty-acid-based additive.

A disadvantage of the additives used is that they do not harden and the fuel is always greasy after addition of the additive and loses the additive again. As a result, this can have the consequence during long storage that the fuel completely loses the additive and all the advantages of the additive are lost.

In addition, the fuel must be transported and stored in special packagings since conventional packagings soften and tear due to the additive or absorb the additive, which would result in an undesirable reduction of the additive in the fuel and in an increased fire risk.

With regard to the undesirable absorption of water, the fatty-acid-based additive in the prior art behaves in a hydrophobic manner and consequently minimises the incorporation of water, but cannot completely prevent this as a result of its continuously diminishing content in the fuel.

A further disadvantage of the fuel in the prior art is that the additive cannot prevent abrasion during transport and storage since the additive does not harden and does not impart any additional stability to the fuel.

When handling this fuel, the user must always wear gloves and take other protective measures to avoid contamination of hands and clothing by the greasy additive.

These disadvantages are unsatisfactory both for the manufacturer and for the purchaser and in addition increase the costs of this fuel.

It is therefore an object of the invention to provide a fuel having an additive which increases the calorific value of the fuel, which completely prevents incorporation of water, which exhibits no abrasion and which can easily be handled.

This object is achieved with a fuel having the features of claim 1 and a method for producing such a fuel according to claim 6.

The basic idea of the invention is to treat a fuel with an additive which enhances the calorific value and hardens.

The fuel according to the invention and a preferred composition of the additive are described hereinafter. Coal can be selected as a fossil starting material for the fuel, wherein all types of coal, e.g. black coal, brown coal or charcoal are available for this purpose.

Any type of biomass is also suitable as starting material as an alternative to a fossil starting material. Non-conclusive examples for this are wood, wood chippings, grain such as wheat, rice, maize, rye, barley, oats or millet, starch, for example, from beans, peas or potatoes, straw, all types of seeds such as olive seeds, palm oil seeds, sunflower seeds, pumpkin seeds and all cellulose-containing substances.

The fuel is preferably pressed into shaped pieces, wherein these shaped pieces can have any possible shape. So-called briquettes or pellets have proved to be particularly suitable shapes.

Before the pressing process, the starting material can be present in any form, i.e. in powder form, as chips etc.

It is understood that mixtures of black coal, brown coal, charcoal and the biomasses are also suitable.

In the process, the starting material or the mixture thereof is pressed into the desired shape at high pressure.

The additive according to the invention which is added to the starting material comprises palmitic acid, stearic acid, lauric acid, myristic acid and oleic acid and comprises the following fractions:

50 to 60% palmitic acid

40 to 50% stearic acid

maximum 3% myristic acid

maximum 1% lauric acid

and traces of oleic acid.

The percentages can comprise both weight percentages and volume percentages.

In this composition, the additive is present in a solid non-greasy form whilst it has the same calorific-value-enhancing property as in the prior art. For this reason, the incorporation of water can no longer form in the fuel treated with this additive and the surface of the fuel is protected against abrasion or crack formation which reduces the breaking of the fuel during transport. Consequently, there are no losses of starting material or additive.

It is furthermore advantageous that the fuel need not be stored and transported in any particular packaging since the fuel does not lose the additive by greasing and does not release any type of dust and the user of the fuel need not take any protective measures against contamination of clothing and hands.

If, for example, barbeque charcoal is treated with the additive according to the invention, this improves the lighting behaviour and also the handling of the barbeque charcoal since there is no risk of contamination to the hands.

In addition, this encapsulation by the additive prevents any formation of fine dust with the result that handling of the fuel is possible without endangering the health of the user. If an increase in the calorific value should only be of interest, the above composition of the additive can be variably adjusted.

A method for producing this particular fuel is explained hereinafter.

During the production of the fuel, the additive can be processed both in the solid and in liquid form. In solid form, the additive is blended in flake form or powder form with the starting material which can be present in any form. After producing a uniform mixture, this is pressed into a specified shape at high pressure. During this pressing the additive is distributed homogeneously inside the shaped pieces and forms a protective layer on the surfaces thereof.

Alternatively, prior to application, the additive can be heated above its specific melting point and used in liquid form. The specific melting point of the afore-mentioned composition is around 62 degrees Celsius.

In this case, the pressing process of the starting material can be carried out both before and after treatment with the additive. The treatment of the starting material can be carried out by passing through or dipping into a bath containing the liquid additive or by spraying it on. It should be mentioned that the treatment of the starting material with liquid additive has the advantage that the incorporated water is expelled due to the hot additive, with the result that the combustibility is further improved. The preferred temperature of the additive when carrying out the treatment is between 70 and 90° but can be higher or lower.

An alternative to the aforesaid additive is paraffin. Paraffin is a wax-like, combustible, odourless, non-toxic and hydrophobic substance which, under certain conditions explained hereinafter has the relevant properties for the invention.

Paraffin designates a mixture of alkanes, i.e. saturated hydrocarbons, wherein paraffin generally has the chemical molecular formula C_nH_2n+2 where n can be between 18 and 50. Depending on the chain length, the melting point varies between 30 and 80° C. and the hardness of the paraffin varies, with the advantageous possibility of selecting a desired melting point and degree of hardness depending on the application. Consequently, the method described above can be carried out unchanged with paraffin.

Paraffin can be used alone or in combination with the additive explained above, it having been found that a mixture with the aforementioned additive has very good properties with a maximum fraction of 50% paraffin.

Furthermore, in cases in which merely an increase in the calorific values is desired, vegetable and animal fats can be used alone or in any mixing ratio. Non-conclusive examples for this are rapeseed oil, rapeseed methyl ester, sunflower oil, linseed oil, olive oil, coconut oil or coconut fat, palm oil seeds, soya oil and all compositions of palmitic acid, stearic acid, oleic acid, myristic acid and linoleic acid.

Claims

1. A fuel comprising a starting material with a first additive, characterised in that the additive comprises 50 to 60% palmitic acid, 40 to 50% stearic acid, maximum 1% lauric acid, maximum 3% myristic acid and traces of oleic acid.

2. The fuel according to claim 1 further comprising a second additive comprised of paraffin.

3. The fuel according to claim 2, the first and second additives each defining a fraction, the maximum fraction of the second additive being as large as the fraction of the first additive.

4. The fuel according to claim 1, the starting material being in shaped pieces.

5. The fuel according to claim 1, the starting material being selected from the group of coal, biomass or a mixture thereof.

6. A method for producing a fuel comprising the following steps:

a) producing a starting material,

b) adding an additive comprised of 50 to 60% palmitic acid, 40 to 50% stearic acid, maximum 1% lauric acid, maximum 3% myristic acid and traces of oleic acid, and

c) pressing the fuel into a particular shape.

7. The method according to claim 6, wherein the additive is heated to at least its specific melting point.

8. The method according to claim 6 further comprising adding another additive comprised of paraffin.

9. The method according to claim 6, wherein the fuel is pressed before adding the additive.

10. The method according to claim 6, wherein the fuel is pressed after adding the additive.

11. A method for producing a fuel comprising the following steps:

a) producing a starting material,

b) adding an additive comprised of parrafin, and

c) pressing the fuel into a particular shape.

12. The method according to claim 11, wherein the additive is heated to at least its specific melting point.

13. The method according to claim 11, wherein the fuel is pressed before adding the additive.

14. The method according to claim 11, wherein the fuel is pressed after adding the additive.

15. The fuel according to claim 2, the starting material being in shaped pieces.

16. The fuel according to claim 15, the starting material being selected from the group of coal, biomass or a mixture thereof.

17. The fuel according to claim 2, the starting material being selected from the group of coal, biomass or a mixture thereof.

18. The fuel according to claim 4, the starting material being selected from the group of coal, biomass or a mixture thereof.