[Stoves] Adding value to charcoal from TLUD stoves

[Julien Winter]

Hello Rajan and all;

In TLUDs, tars may condense in the char above the pyrolysis front, if the
temperature decreases substantively with height in the char layer.

However, your assertion that ---

"The pyrolysis process has to be extended by a couple of minutes ( after
the flame drops down )  -  so that all volatiles in the charcoal are
"forced out" ( with the high temperature of charcoal burning ) which
increases the porosity of charcoal."

---  may be true, if the temperature of the char increases during the
charcoal gasification phase.  Evidence of this can be seen in Figure 4 of
the following paper.  It is for a forced-draft TLUD running at a
superficial velocity of 4.5 cm/s.

Varunkumar, S; Rajan, NKS; Mukunda, HS. 2011. Single particle and packed
bed combustion in modern gasifier stoves--density effects. Combustion
Science and Technology 183: 1147-1163.

http://cgpl.iisc.ernet.in/site/Portals/0/Publications/ReferedJournal/Single-Particle-and-Packed-Bed-Combustion.pdf

(You may need to use a download assist program to get this pdf)

Can anybody corroborate these observations?

Cheers,
Julien.



-- 
Julien Winter
Cobourg, ON, CANADA
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