[Gasification] char and gasifiers

[Pels, J.R. (Jan)]

Charcoal is recalcitrant, but it breaks down. It is not stored
indefinite, but slowly decomposes at various rates. You can find
remainders of fires from prehistoric time - even from Neanderthals - but
only if they have been sheltered from water, e.g., in caves. Biochar
will slowly wear off and is then recycled into the biosphere. Lehmann
acknowledges this: "biochar is orders of magnitude more stable". 

The question is how long is long enough? What the minimum time scale for
being call 'fossilized' is open for debate. A nice example is peat of
10.000 years old. The Finns, who use it as fuel, claim that it is
'slowly renewable', but the European Union does not regarded it as a
renewable fuel. 

Jan

========================================
Dr. Jan R. Pels
ECN - Biomass, Coals and Environmental Research
P.O. Box 1, 1755 ZG Petten, The Netherlands
telephone: +31-224-564884; fax: +31-224-568487
mobile: +31-6-10923218
e-mail: pels at ecn.nl
========================================
 
 

> -----Original Message-----
> From: gasification-bounces at listserv.repp.org 
> [mailto:gasification-bounces at listserv.repp.org] On Behalf Of Tom Miles
> Sent: Tuesday, October 09, 2007 10:19 PM
> To: 'Reg Preston'; 'Gasification'
> Subject: Re: [Gasification] char and gasifiers
> 
> Reg,
> 
> The argument that Lehmann and others propose is that the 
> charcoal is recalcitrant - the carbon doesn't break down - so 
> it is indefinite. It's primary function is as a habitat for 
> microorganisms that provide nutrients to the plants.
>