[Stoves] Heat to sustain TLUD process

[Paul S. Anderson]

Andrew, Tom and all,

Thanks to Tom and Andrew for their thoughtful inputs.  I can let the giants
hammer it out and I can be learning on the sidelines.

Summary of what I am learning:  at the lower temperatures, C + O2 is 
virtually a
direct reaction to become CO2, without the intermediate formation of CO.  And
that is very exothermic.  Is there a name for this specific reaction?  "carbon
oxidation" does not sound right.  It is NOT "char gasification" or
"carbon-gasification" UNLESS you can clearly distinguish this reaction 
from the
  2C +  O2 => 2CO   reaction.

Question:  What amount of fixed char (C) is needed to give the heat for the
pyrolysis?  If very little char, then that at least allows Alex's view to be a
possibility.

Quoting AJH <list at sylva.icuklive.co.uk>:

> but in fact we could test this with simpler equipment by
> heating an identical amount of the fuel in a sealed container with a
> one way vent, to the same temperature and comparing the offgas and
> char.

I think not.  The zone of the redhot char is very thin, but to take a realed
container up to those temperatures requires that the entire fuel contents are
heater.

Alex questions about the flame or spark for ignition of combustible gases.  At
the level of molecules and small amounts of fuel, I suspect that the heat of
the glowing-red char constitutes a constant "spark."  Question:  is glowing
char sufficient to ignite hot, dense pyrolysis gases if oxygen is 
present?  [if
an ignited cigarette that has no flame but glows can cause an explosion of
combustible gases with O2, glowing char should be able to ignite gases in the
pyrolysis zone of a TLUD.

Alex mentioned the case of not having any spark present and would the gases
ignite (sorry I snipped it already).  In a TLUD there IS spark/flame present
from the beginning (that is how we get it started).

At this moment, I find myself in the middle and suspect that BOTH char and
pyrolyis gases are "burning" to keep the TLUD functioning.

Paul


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