[Stoves] coconut usage in improved stoves continued

[Alex English]

Art,
Have you got any data on char cation exchange capacity?
Alex



On 17/06/2013 2:23 PM, Art Donnelly wrote:
> Hi all,
> I want to provide some information on the ability of ND TLUDs to 
> utilize coconut waste as an input material as well as comment on the 
> relationship between the temp. at which char is produced and the 
> issues of yield and surface area.
>
> Coconut shell and coir burn very well and very cleanly in the ND 
> Estufa Finca TLUD.
> Obviously the dense shell is preferred for it's longer burning time, 
> but the mix gives us a great biochar, which the nursery men seem to 
> like. Perhaps this works well in this stove because we use more 
> secondary air than I see in some other similar stoves? As with other 
> fuels, we can continue to add this material to the stove as it burns, 
> to extend cooking time. This strategy does result in a lower yield of 
> char, than the straight load and burn to completion method.
> When we load the stove, light it and run it until the flame color 
> changes we routinely yield 30-33% of the the original dry weight of 
> the input material as biochar.
>
> I monitor both our Estufa Finca stoves and 55-gallon drum J-RO kilns 
> with a K-type digital probe thermometer. The stoves pyrolysis front 
> produces char between 500-700c the J-RO between 600-800c. I have had 
> Hugh McLaughlin characterize approx. 14 samples of different material 
> made in these and material processed in retorts with a temperature not 
> exceeding 450c. The biochar from the TLUD type devices all have 
> greater available surface area than the same materials produced at the 
> lower temperature range. Wood, bamboo and coconut shell all come in 
> around 400m2/g. Close to the low end for activated charcoal. These 
> chars are giving us good results in the soil when mixed with compost 
> or inoculated with EM. The reduction in tars in the higher temp. chars 
> is a plus.
>
>
> Art.
>

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