[Stoves] coconut usage in improved stoves continued

[Crispin Pemberton-Pigott]

Dear All

 

I have spent some time trying to burn whole coconut husks – some may remember the reported experiments some time in 2003.

 

The motivation was the fact that Mozambique has a huge amount of the material lying around and while it is used for a domestic fuel, it is pretty awful. It is heaped around pots and burned with a great deal of smoke.

 

I was in Swaziland at the time (where New Dawn Engineering is located) and was developing the Vesto. A number of experiments were conducted using a Tsotso stove which can burn just about anything. The observations were that the husks can burn very cleanly (visibly clean, at least) if it is burning in a staged process. While the fuel can hold considerable moisture, once it is heated to the point of getting rid of the steam, it is able to burn well, producing a white smoke that supports combustion if given preheated secondary air.

 

In order to sustain a burn it is essential that the fuel be dried enough. It is likely that any practical device will have a method of supply new fuel continuously or in batches, perhaps pushed in from the side or the bottom. Preheating the primary air is essential because of the retained moisture.

 

Because the ‘fuel particles’ are so large, the device will have to be large. If it is a TLUD or downdraft (BLDD) stove it implies that he chamber will be >6 times the particle size. If the husks are not cut into pieces that implies a diameter of perhaps 60-75 cm. I guess the power level would 10-20 kW. To be useful the things should perhaps be 1.5-2 metres high.

 

At that size, it could be used to make soft charcoal on a reasonable scale for briquetting. Given the vast local market for charcoal in Mozambique it might make sense, all things considered.

 

Regards

Crispin

 

 

 

Paul

 

What would a TLUD sized for coconut husks look like? Can you suggest dimensions and a fuel size?

 

Tom





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