IE870186L

IE870186L - Fuel briquettes

Info

Publication number: IE870186L
Application number: IE18687A
Authority: IE
Original assignee: Maxiheat Anthracite Briquettes
Priority date: 1986-01-23
Filing date: 1987-01-23
Publication date: 1987-07-23
Also published as: PT84189A; EP0231097A2; GB8701291D0; IE59809B1; GB8601670D0; EP0231097A3; GB2185755A; GB2185755B

Description

59809 2 It is an object of this invention to utilise waste products from the industrial refining of oils for the purpose of constructing a solid fuel which may be used for heating purposes.

Accordingly this invention provides a solid fuel briquette constructed from a mixture of anthracite 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 incorporating 10 a hydrocarbon based binder and having been pressed to form a solid fuel briquette, the constituent parts in the final product, in an uncured state, being present in the ratios of 10% to 60% of the by-product and 1% to 10% of binder, with the balance being 15 anthracite duff, all proportions by weight.

The by-product (presently known as "'petroleum 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 used 20 for domestic fires and heating appliances. Desirably the binder will be present in an amount of 3£% to 8%, preferably 4£% to 7%, in the form of a basic material added to the anthracite duff and petroleum coke during initial mixing, although there can be up to an extra 25 3% of binder (so long as the total binder content does not exceed 10%) incorporated in any 3 recycled material.

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 5 should be cured to the extent that the binder is reduced to an amount of 0.5% to 1,5%,, desirably about 1%„ For a smokeless fuel of this nature the amount of binder incorporated in the initial mixture (from all sources) will desirably be between 4% and 5% prior 10 to the curing stage. This smokeless fuel can be used on domestic fires and in heating appliances and in solid fuel cookers.

The binder itself is ideally bitumen and although tar or pitch could be used insteada more preferred 15 alternative is lignosulphonate.

Ideally the particle sizes of the grains of petroleum coke and anthracite duff are less than 3mm, 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 hereinbefore defined,, wherein the anthracite duff and the petroleum coke are mixed together in the required proportions together with the binder and the mixture 25 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 this process the briquette is passed through a curing oven to oxidise 5 excess binder to form a smokeless fuel having a binder content of between 0'„5% and 1.5%. Preferably the initial binder content, before oxidation, is between 4% and 5%.

The invention may be performed in various ways and a preferred example thereof will now be described: 10 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 15 which will remove larger products of a size greater than 7mm. 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 20 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 3mm, the crushed mixture then being passed to a dry storage hopper. 2 5 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 5 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 10 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 15 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 briquettes 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 cured).

Ideally for the smokeless fuel the final bitumen content will not be less than 0.5% or greater than 0 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 5 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 10 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 by-product derived from the refining of heavy fuel oil to light fuel oil and called "petroleum coke", the mixture also incorporating a hydrocarbon based binder and having been pressed to form a solid fuel briquette c the constituent parts in the final productt in an uncured state, being present in the ratios of 10% to 6 0% of the by-product and 1% to 10% of binder, with the balance being anthracite duff, all proportions by weight.

2. A briquette according to claim 1, wherein the petroleum coke is present in an amount of 15% to 50% by weight.

3. A briquette according to claim 3, wherein the petroleum coke is present in an amount of 20% to 40% by weight.

4. A briquette according to claim 1, wherein the petroleum coke is present in an amount of 25% to 35% by weight.

5. A briquette according to any one of claims 1 to 4, wherein the particle sizes of the grains of petroleum coke and anthracite duff are less than 3itun.

6. A briquette according to any one of claims 1 to 5, wherein the binder is present in an amount of B 3j% to 8 % t„ as an added material with up to an extra 3% provided from recycled waste, to give a total binder content of no greater than 10%.

7. A briquette according to any one of claims 1 5 to 5, wherein the binder is present in an amount of 4|% to 7%, as an added material with up to an extra 3% provided from recycled waste.

8. A briquette according to any one of claims 1 to 7, wherein the binder has been cured to reduce the 10 amount of binder present to 0.5% to 1.5%.

9. A briquette according to any one of claims 1 to 7, wherein the binder has been cured to reduce the amount of binder present to II.

10. A briquette according to any one of claims 1 15 to 9, wherein the binder is tar or pitch.

11. A briquette according to any one of claims 1 to 9, wherein the binder is lignosulphonate or bitumen.

12. A solid fuel briquette according to claim 20 1, substantially as herein described.

13. A method of forming a solid fuel briquette as defined in any one of claims 1 to 12, wherein the anthracite duff and the petroleum coke are mixed together in the required proportions together with 25 the binder and the mixture is then pressed to form briquettes.

14. A method according to claim 13 £, wherein the binder is -introduced by injection into the anthracite duff and petroleum coke after they have been thoroughly mixed together prior to forming the briquettes.

15. A method according to claim 13 or claim 14, 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%.

16. A method according to claim 15, wherein the initial binder content, before oxidation, is between 4% and 5%.

17. A method according to claim 13 of forming a solid fuel briquette, substantially as herein described.

18. A solid fuel briquette whenever formed by a method claimed in a preceding claim. F. R. KELLY & CO., AGENTS FOR THE APPLICANTS.