Burning of Coal Briquettes

Well I see a few possibilities, reducing moisture content might help, a further refining process to remove more ash, adding an accelerant or raising the cv content via mixed waste streams...These most desirably from another local waste stream...I would look for any waste oil streams, or paper, or perhaps the farmers themselves...

Moisture is very low 4%. I think the ash removal process is a good idea any suggestions of the technology that I can use for ash removal process and if possible expected cost.

http://www.homebase.co.uk/webapp/wcs/stores/servlet/ProductDisplay?langId=110&storeId=10151&partNumber=931437

Can't say what would work for you, or the related cost...You might want to take a closer look at other processes that are working...

http://www.greenfieldscoal.com/documents/GreenFields_V3.pdf

Are you looking for a way to have the briquettes burn faster, to give up more heat?

If so, you need to increase the surface area of the briquettes. They'll burn faster and hotter if there is more surface area exposed to air. You might consider putting a large hole through each briquette, or creating a textured surface with large grooves. Or try doing both.

If you mix briquettes with holes/texture along with one that are solid/smooth you'll get the intermediate effect of somewhat more heat, faster, (due to the ones with increased surface area) plus long burning time (due to the compact ones).

it would have been better of it was extruded by putting a hole in it, but if it was a briquette, to gain surface area instead of putting a hole in it, reduce the size.

I do not know what size is the briquette, but it may be a better idea to pelletize the char.

I would suggest using a forced draft (blower) and that would allow feedback loop to reduce the draft once the temperature is at desired level.

As I understand it, the farmers original coal cv was 24 to 27kj/kg and your briquettes are 19.5 to 24kj/kg. If I'm not mistaken you are feeding a much larger coal particle with a much less heating value?

Therefore, perhaps as someone said try to reduce your briquette size and feed more, meaning feed more briquettes to make up for the lower heating value.

Or since your larger particles are going to heat slower then you are going to have to increase the oxidation, by a higher jet air flow or the addition of oxygen to the air flow.

Your briquettes take longer to burn and have lower heating value than what the farmers expect. But they are cheap, so maybe they can gain acceptance if they can make them burn faster.

Some questions might help to troubleshoot here: What binder do you use for the briquettes, and why is it the best? How do you separate the clay from the coal? Does your crushing process grind up big chunks of minerals as well as the coal? Is the mineral content the reason your briquettes have such a low heating value? What size and shape are the briquettes?

The feed material is taken straight from the fines dump without any cleaning. We do not crush anything as the feed (raw material) is a by-product of the coal processing process. These dumps have been there for decades now and we are just reclaiming the dumps like what the gold and diamond market benefited from the old dumps due to advancement in technology.

We are using an alcohol based binder. Its polyvinyl alcohol if I am not mistaken. We only put 0.3% of the binder in the briquette. That is the binder mass is 0.3% the mass of the briquette. The briquette also has a high ash content about 27%. The size is 28X30X10 all dimensions in mm. It has rounded corners.

Lancoz:

Can I get more information on this binder.

We make food ingredients with our primary ingredient being liquid smoke. By pulling the flavorings out, the process removes the lignin out that which is a natural binder.

Out ash content is only about 2%.

We generate over 12,000,000 pound of char/year. With the coal fired generators switching to natural gas. An we are currently looking for alternative uses for this.

Our other outlet we are looking in to is activating it the char.