[Stoves] [Jatropha cake properties]

[Crispin Pemberton-Pigott]

Dear Christa and Paul and Others contributing to this interesting angle

 

As you may know I have been making oil presses for quite a  long time and
looking at quite a lot of seed cake ('torteau' in some countries). Cake left
alone, when there is a reasonable amount of oil in it, hardens as the oil
degrades and as the whole thing dries. Old oil usually it makes a blackish
hard, dry scale on things. In other words it is a binder but a slow one.
Marula kernel cake is way too valuable as a food to burn (presuming you have
taken care not to allow fusareum roseum to grow on the seeds). Sunflower
cake is probably like the jatropha cake.

 

If you have a low(er) pressure press it leaves a fair bit of oil in the
cake: often 15%, maybe 10% from a screw press, only 6% after solvent
extraction.  The higher numbers are enough to become a binder, not a
problem, if the post-processing is patient and correct. Obviously the
fibressness (fibrosity?) of the mix and the amount of pure powder and all
sorts of physical properties affects the result, but in principle, it is not
necessarily a negative to have an oily and powdery cake.

 

Perhaps it needs to be compressed gently and heated to accelerate the
breakdown of something, to dry it, to get something to grip. It may need an
additive to be the binding fibre, or a chemical that accelerates the
conversion of an oil to a dry hard goo holding things together.

 

It sounds like the best way to burn the J-cake (J-torteau = Jorteau!) is to
try combustion systems that do not try to pull air through the fuel. An
angled downdraft would to (using a wire grate) as would some side draft
approaches though they would require periodic feeding. My bet is downdraft
will be best because it removes the ash and provides new fuel at a
known/fixed place. In that case there would be no air pulled through the
fuel - i.e. it is loaded into a sealed hopper.

 

If it is sticky/oily, the hopper should taper slightly larger towards the
bottom.

 

If there is an approximate equivalent that is perhaps more accessible we
could all try versions of 'cake burners' that can deal with, say, rolled
oats and crushed wood pellets and sawdust - that sort of thing.

 

Regards

Crispin

 

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