[Terrapreta] Folke's retort kiln

[Kurt Treutlein]

Philip Small wrote:
> There is no draft in the inner barrel.  It releases wood gas under 
> pressure, but that is different. No charcoal is retained from the 
> outer sleeve, it is all sacrificed to drive the retort (inner can). 
> The significance of being able to crack the smoke to get more H2 and 
> CO is that you get more heat value to drive the retort than with a 
> less efficient configuration, not that the process could be used to 
> yield charcoal, a capability which can be employed in cooking stoves 
> which use the same top-lit gasification-related principles. (Example 
> <http://www.youtube.com/watch?v=PpozW9039_o>)
>
Philip,

The reduction re-action between hot carbon and H2O and CO2 that results 
in H2 and CO formation needs at least 400degreesC, it  absorbs heat and 
is probably not of any significance in this situation anyhow. The 
"smoke" consists of a fine mist of condensed tars and heavy liquids as 
well, possibly, as steam, which should have burnt earlier in the 
combustion zone. The fact that it is there at all probably indicates a 
lack of air. We should not confuse what is happening here with what 
happens in a gasifier of the kind designed to fuel internal combustion 
engines.



regards

Kurt