[Stoves] Challenging fuel

[energiesnaturals]

As Marc says, almond shells come in many shapes and sizes,even biger than 40 mm and down to small hazel nut size. They break like glass, are not  fibrous, but 
have always a varying amount of the outer " fruit " shells in them.
These are different, easily distinguished bytheir leather like appearance.

E have been trying to make a standard fuel as for pellet sbstitute out of the and the best we have found is putting them through a modified hammer mill and seiing away the dust< 3 mm. This represents between 20 and 25 % min!

Marc has used these small shells and yes, they didn ' t work in a Tlud.

But there have been burners for these shells and whole shells for ages.

These simple devices have a hopper and a stair like inclined grate.
They exist from a few kw up to 100 or more kW and you can still buy them today.

They can be regulated to about 50% and are continuously fed, which ,means that one is not limited to a batch cooking time. You can use them for cooking and heating .
Small and powerfull and simple cast iron devices. No Tluds, though.

RolfCrispin Pemberton-Pigott <crispinpigott at outlook.com> hat geschrieben:Dear Marquitusus
 
The fuel looks really good. I agree with Richard that breaking it down to a certain ‘sieve size’ might be a good idea but if you want an almost-no-equipment solution, sieves are fine.
 
I agree with Julien that getting the largest and smallest pieces divided into two piles is a good start but only after removing the pieces smaller than 6mm. So there will be two fractions: larger and smaller than 14mm or so. I have no strong opinion on the divide – test it and see.
 
However my more important point is that the smaller portion of the shells should be loaded first and put the larger fraction on top. The larger shells pieces will light more easily and spread the fire more readily across and into the surface.
 
One of the consistent complaints about TLUD’s from users is that the fire takes too long to get going. I have been promoting the user of a lighting cone here on the list but I haven’t heard that anyone is using it. When the fuel pieces are larger, the small burning pieces fall further down into the fuel bed lighting a larger amount of fuel than would happen with small pieces. The spaces between small fuel chips prevent the fire spreading downwards rapidly. In the beginning people usually want a hot fire quickly. Segregating the fuel by size can assist that spread in the early stage.
 
Later when the whole stove is hot, the small chips will prevent the fire from accelerating downwards and producing too much gas to burn.
 
For the smallest bits, they can be made into biomass briquettes using leaves or paper in ‘the regular way’. Small hard pieces of shell are perfect for adding to light biomass briquettes.
 
For lighting, it is still good to use a lighting cone to accelerate the development of the fire across the top of the fuel. In almost all cases it reduces emissions (a lot) as well.
 
I have conducted a number of tests with pistachio nut shells which are very constant in size and shape. Because they are so light ignition is easy but it is hard to limit the gasification rate due to the small coals dropping vertically into the spaces. “Flattening” them helps get the bulk density up to the point where they behave better.
 
Regards
Crispin
 
 
Dear stovers,

I send you a picture of the fuel I'm trying to deal with.
This is the raw fuel as it is normally sold here. They are almond husks.
As you see, it's sizes varies from 1 to 40mm!

Maybe people can tell me how this can affect the TLUD design

 
 
 
 
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