[Stoves] Calculating th LHV for Biomass and Coal

[Crispin Pemberton-Pigott]

Dear Dr Tom and Kevin

 

Thank you both for responding.  I am working on the remaining charcoal in a
fire so the issue of its moisture content doe not arise.  It is presumed
that charcoal that is either presently burning or was recently formed in the
fire has zero moisture content.  In fact that water loss has to be accounted
for in the calculation of the net heat yielded by burning the wood and
volatile portion.

 

If there is no visible method for assessing what 'average charcoal remaining
in a fire' contains in terms of volatiles, then I will have to use
'ordinary' charcoal (which is not consistent) and announce that the subject
is not closed, or perhaps even closeable.

 

Dr TR>The LHV of biomass is then ~ 21-2.5 = 18.5 kJ/mole or 1.03 kJ/g, ~ 12%
less than the HHV. good enough for a general rule and warning.

 

Actually when I tried that it did not work out so well as will be seen in a
forthcoming message.  The HHV of our fuels ranges from about 12 to 21 MJ/Kg
while the water energy demand remains constant per gm.  The charcoal heat
content is probably pretty constant for our stove conditions, exacerbating
the problem because if the wood heat energy for a certain species is low,
and the charcoal heat content is constant, there is an ever-increasing gap
between the calculated value (using that method) and the real value.

 

Can I take the Hydrogen content of charcoal to be 2%?

 

Regards

Crispin