Re: BioC: Re: Pyrolysis vs. Gasification

["Antonio G. P. Hilst" <antonio.hilst@merconet.com.br>]

Dear Harry and Harris,
Perhaps you both cold elaborate on the gasification/pyrolisis using a "severity"
parameter such as C/O ratio, temperature, etc.
Anonio Hilst

VHarris001@aol.com wrote:

> In a message dated 12/28/2000 9:50:15 PM Eastern Standard Time,
> H.Parker@ttu.edu writes:
>
> > Gasification is reaction of organics with steam and the products are carbon
> >  monoxide and hydrogen, called synthesis gas.
>
> Hi Dr. Parker,
>
> Having spent more than a little time reading posts over on the gasification
> list hasn't exactly clarified my understanding of the definition of
> "gasification."  For our benefit, would you compare and contrast pyrolysis,
> gasification and starved-air combustion?  For instance, does gasification
> "require" reaction of organics with steam?  By this, I suppose correctly that
> you to mean the water-gas reaction: C + H2O + 131,400 kJ/kg mole => CO + H2?
>
> I've been told that this highly endothermic reaction is sustainable when
> "gasifying" coal.  On the other hand, since it is so endothermic, I've
> understood that the wood-gas reaction is not sustainable to any substantial
> degree in "gasification" of wood.  If this is true, then my presumption is
> that wood "gasification" is primarily a starved-air combustion process,
> liberating volatiles to be combusted downstream.  Further, my impression is
> that if the superficial velocity (and thus the combustion temperature) is
> kept sufficiently high, then a high percentage of tars can be cracked to
> permanent gas, resulting in a low-tar volatiles stream suitable for internal
> combustion engine use.
>
> I'm wondering what your take is on the "gasification" of wood?  Is it
> primarily the wood-gas reaction or a starved-air combustion process?
>
> Thanks,
> Vernon Harris
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