[Stoves] why does charcoal produce more CO?

[Andrew Heggie]

On 26 January 2018 at 01:31, Darpan Das <darpandasiitb at gmail.com> wrote:

>
> Thanks Andrew.
>
> I was also wondering if the decrease in bound oxygen content would have
> any role to play in the increase in co emissions. My ultimate analysis
> results for wood and charcoal show that charcoal has negligible O/C
> content. This probably is because of the pyrolysis process for wood has
> already removed the volatiles. Now the charcoal is more energy densified
> containing most of it part as carbon.
>
> Can this less O present in the solid fuel matrix be attributed as a reason
> for formation of high CO?
>
>
Darpan

Crispin has replied to this.

By the time the fire is reduced to a glowing bed of coals there will be
little oxygen bearing compounds left.

In the early stages of pyrolysis CO is given off and this is  a result of
the decomposition of wood, so yes the CO is a product from the
decomposition of oxygen beariing compounds in the wood.

The reduction of CO2 by carbon to CO only takes place at higher
temperatures by which time the char  is nearly all carbon with no oxygen
bearing compounds remaining.

If the firebed is thin and able to radiate its heat freely so it looks like
"black" heat the conditions for making CO from char don't exist and the
char should oxidise directly to CO2, as the bed gets deeper and the heat
cannot escape then the conditions  are there.

I cannot imagine what -56C is like +40C was bad enough

Andrew in balmy England
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