GB2185755A

GB2185755A - Sold fuel briquettes

Info

Publication number: GB2185755A
Application number: GB08701291A
Authority: GB
Inventors: Owen Glyndwr Yemm; Albert John Yemm
Original assignee: MAXIHEAT
Current assignee: MAXIHEAT
Priority date: 1986-01-23
Filing date: 1987-01-21
Publication date: 1987-07-29
Also published as: IE59809B1; GB2185755B; GB8601670D0; EP0231097A3; GB8701291D0; EP0231097A2; PT84189A; IE870186L

Abstract

A solid fuel briquette is constructed from a mixture of anthracite duff and petroleum coke held together by bitumen or some other hydrocarbon based binder, the mixture having been pressed to form the solid fuel briquette. The final product can incorporate the constituents in the ratios of 10% to 60% of petroleum coke, 1% to 10% of the binder, with the balance being anthracite duff, all proportions being by weight.

Description

I GB 2 185 755 A 1 [I 1.

SPECIFICATION

Improvements relating to solid fuel briquettes 65 It is an object of this invention to utilise waste 5products from the industrial refining of oils for the purpose of constructing a solid fuel which may be used for heating purposes. 70 Accordingly this invention provides a solid fuel briquette constructed from a mixture of anthracite 10 duff, and a carbon based by-product derived from the refining of heavy fuel oil to light fuel oil and called -petroleum coke", the mixture also 75 incorporating a hydrocarbon based binder and having been pressed to form a solid fuel briquette, 15 the constituent parts in the final product being present in the ratios of 10% to 60% of the by product and 1 % to 10% of binder, with the balance 80 being anthracite duff, all proportions by weight.

The by-product (presently known as "petroleum 20 coke") is thus used as part of the fuel and burns with the anthracite duff, the two main constituents being held together by the binder. This solid fuel can be 85 used for domestic fires and heating appliances.

Desirably the binder will be present in an amount of 25 31% to 8%, preferably Q'% to 7%, in the form of the basic material added to the anthracite duff and petroleum coke during initial mixing, although there 90 can be up to an extra 3% of binder incorporated in any recycled material.

30 A smokeless fuel can be formed by curing the formed briquette in a curing oven to oxidise excess binder. It is preferred that the finished briquette 95 should be cured to the extent that the binder is reduced to an amount of 0.5% to 1.5%, desirably 35 about 1 %.For the smokeless fuel of this nature the amount of binder incorporated in the initial mixture (from all sources) will desirably be between 4% and 100 5% prior to the curing stage. This smokeless fuel can be used on domestic fires and in heating 40 appliances and in solid fuel cookers.

The binder itself is ideally bitumen and although tar or pitch could be used instead, a more preferred 105 alternative is fig nosu 1 phonate.

Ideally the particle size of the grains of petroleum 45 coke and anthracite duff are less than 3 mm. This ensures good compaction resulting in a robust briquette.

The invention also extends to a method of forming a solid fuel briquette of this invention as 50 hereinbefore defined, wherein the anthracite duff and the petroleum coke are mixed together in the required proportions together with the binder and 115 the mixture is then pressed to form briquettes.

Ideally the binder is introduced by injection into the anthracite duff and petroleum coke after they have been thoroughly mixed together and crushed prior to forming the briquettes. As a modification of 120 this process the briquette is passed through a curin oven to oxidise excess binder to form a smokeless 60 fuel.

The invention may be performed in various ways and a preferred example thereof will now be 125 described:

Example

A solid fuel briquette of this invention may be formed in the following manner. Anthracite duff (which since it will be stored out of doors can be in a wet state) is passed along a belt conveyor to a screen which will remove larger products of a size greaterthan 7 mm. The petroleum coke is then added to the conveyor to achieve a ratio of anthracite duff to petroleum coke of 70% to 30%. The resulting mixture is then passed to a wet storage hopper. The wet mixture is subsequently fed over a fluidised bed dryer to achieve a final moisture content of 3% to 5% and is then fed into a hammer mill to crush the particles down to a grit size of less than 3 mm, the crushed mixture then being passed to a dry storage hopper.

For the briquette forming process the mixture is conveyed to a mixing chamber incorporating a stirring device which thoroughly mixes the material whilst steam and bitumen is injected, to achieve a bitumen content of 4% to 7%. The resulting mixture is then fed to press rolls which create the shaped briquettes whilst compacting the mixture so that the particles are held together by the bitumen binder. The briquettes are then fed to a vibrating feeder to remove any flashings.

The flashings, which may contribute up to 3% bitumen content, are recycled and only utilised for the manufacture of non-smokeless fuel briquettes. This should be borne in mind when determining the desired final bitumen content.

A smokeless fuel can be formed by placing the formed briquettes into a curing oven where a constant temperature of 300'C is maintained as the briquettes pass through seven zones within the oven during a period of about an hour and a quarter. Air is circulated to oxidize the bitumen as required so that a final bitumen content of about 1 %_ is achieved. The briequettes are then quenched. If the smokeless fuel briquette is to be formed, then a slightly lower initial bitumen content should be created in the initial mixture (for example, 4'% as opposed to 7% for a briquette which is not to be cu red). Ideally for the smokeless fuel the final bitumen content wil 1 not be less than 0.5% or greaterthan 1.5%.

Whilst the quantity of petroleum coke in the mixture could be as low as 10% this is really of minimum financial benefit and furthermore improvement in crushing strength of the final briquette is only really noticeable when the petroleum coke is present in an amount of greater than 20%. At the upper range above 40% can create problems due to the mixture becoming too lumpy and creating blockages although with suitable equipment, it could be possible to cater for up to 60% of petroleum coke.

Claims

1. A solid fuel briquette constructed from a mixture of anthracite duff, and a carbon based byproduct derived from the refining of heavy fuel oil to light fuel oil and called "petroleum coke", the mixture also incorporated a hydrocarbon based binder and having been pressed to form a solid fuel 2 GB 2 185 755 A 2 briquette, the constituent parts in the final product being present in the ratios of 10% to 60% of the byproduct and 1 % to 10% of binder, with the balance being anthracite duff, all proportions by weight.

5 2. A briquette according to claim 1, wherein the petroleum coke is present in an amount of 15% to 50%, preferably 20% to 40%, desirably 25% to 35% byweight.

3. A briquette according to claim 1 or claim 2, 10 wherein the particle size of the grains of petroleum coke and anthracite duff are less than 3 mm.

4. A briquette according to any one of claims 1 to 35 3, wherein the binder is present in an amount of 312% to 8%, preferably 4% to 7% as an added material 15 with up to an extra 3% provided from recycled waste 5. A briquette according to any one of claims 1 to 40 3, wherein the binder has been cured to reduce the amount of binder present to 0.5% to 1.5%, 20 preferably about 1%.

6. A briquette according to any one of claims 1 to 5, wherein the binder is tar or pitch, or preferably 45 lignosulphonate or ideally bitumen.

7. A solid fuel briquette substantially as herein 25 described.

8. A method of forming a solid fuel briquette as defined in any one of claims 1 to 7, wherein the anthracite duff and the petroleum coke are mixed together in the required proportions together with 30 the binder and the mixture is then pressed to form briquettes.

9. A method according to claim 8, wherein the binder is introduced by injection into the anthracite duff and petroleum coke after they have been thoroughly mixed together priorto forming the briquettes.

10. A method according to claim 8 or claim 9, wherein the briquette is passed through a curing oven to oxidise excess binder to form a smokeless fuel having a binder content between 0.5% and 1.5%.

11. A method according to claim 10, wherein the initial binder content, before oxidation, is between 4% and 5%.

12. A method of forming a solid fuel briquette substantially as herein described.

Printed for Her Majesty's Stationery Office by Courier Press, Leamington Spa, 711987. Demand No. 8991685.

Published by the Patent Office, 25 Southampton Buildings, London, WC2A 1AY, from which copies may be obtained.

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