[Stoves] Charcoal stove design

[Crispin Pemberton-Pigott]

Dear Frank

 

>Charcoal largely burns C > CO2 and converts some of it back to CO in the
hot zone above the hot coals. [Frank >] Above the hot coals or in the hot
coals? To convert back from CO2 > CO we need more carbon. 

 

I found that directly above the middle of a good stove (under the pot) there
is zero CO - I was amazed. But nearer the edges there is more.

 

>If the excess air level is high it can create a lot of CO directly and not
burn it. [Frank >] Is it because the gas is too cool? Molecules are spread
too far apart to continue the complete combustion? Not enough hydrogen to
aid in supporting continued complete combustion? 

 

All the above. Well done.

 

[Frank >] I find the hydrogen is less than one percent in char. But moisture
can increase the hydrogen is not tested directly after drying. Wonder if
this water hydrogen is any help in these small stoves?

 

Well that is the question of the hour - where does all the H2 come from?

 

I checked a number of other tests and the correlation coefficient between CO
and H2 varies a great deal. The 97.7% was interesting of course, but some
are negative and some are 50%.  I don't think this is an instrument issue,
it represents different combustion conditions, largely.

 

Regards

Crispin near the Forbidden City

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