[Stoves] Inverted top lit updraught

[Alex English]

Andrew,
Can we melt steel with torrified wood?

I'm trying to follow your thinking on the propane flame, inner/outer 
business. Are your suggesting that the pyrolysis gasses be kept 
separated from the CO from charcoal gasification  in one device like the 
Dasifier and then burn the latter inside the former.

The other Das trick to elevating the useful temperature is the intense 
mixing he generates with his compressor induced flows, thereby 
maximizing the heat flux  in a small volume.
Is the necessary retention time for complete combustion inversely 
proportional to the turbulent mixing rate of the fuel gas and air?

Alex









An 1 Further musings: [1] it should be just about possible to melt steel 
with a wood flame if the wood is perfectly dry, in practice it doesn't 
happen and iron was not produced until charcoal was used, the reason is 
simple; whilst the charcoal only has <50% of the heat of the raw wood it 
was produced from, it is dry nearly pure carbon with about 30MJ per kg 
available to be released on full oxidation. C+O2+4N2=>4N2+ CO2+30MJ heat 
per kg of C is a low massflow reaction and heats of over 2000C are 
achievable. Consider a propane torch flame, when premixed with the 
correct amount of air the flame is two blue flames, a bright blue inner 
flame surrounded by a paler blue enveloping flame, the hottest part is 
at the tip of the inner cone where nearly all of the premixed oxygen is 
consumed burning hydrogen and some carbon to H2O and CO/CO2, remaining 
CO is then burned in the outer enveloping flame by oxygen that has 
survive the first flame and oxygen that diffuses in from the surrounding 
air. Can we consider doing something similar with the dasifier, using 
the high mass flow ~1600C pyrolysis offgas flame to form a hot envelope 
around the lower heat capacity but higher temperature CO+N2 flame? 
Without destroying the burner pipe from the heat? AJH 
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