[Terrapreta] Farm Scale Batch Charcoal Furnace for Homestead orFarm

[AJH]

On Mon, 21 Apr 2008 13:11:20 -0500, Sean K. Barry wrote:

>A farm scale Charcoal Kiln should pyrolyze charcoal without releasing Methane-CH4. 

I'd say it should do it without any of the pollutants normally
associated with charcoal kilns, CO and carcinogenic PICs being more of
a concern that the climate changing potential of methane.


> NOx emissions are not a problem at lower pyrolysis temperatures (let's say, less than 600C). 

It's not the producing NOx in the carbonisation stage that I was
referring to, temperatures are too low for atmospheric nitrogen to
combine with oxygen. The problem potentially arises at high
temperatures and with excess air in the secondary burn of the offgas.
As this is a relatively low calorific value gas, albeit already at
~500C, and as excess air lowers the temperature, we're only talking
about 1200C typically, I do not consider it a problem compared with
fossil fuels typically burning at over 2000C.


AJH