[Terrapreta] Fw: new address to the simple kiln

[Philip Small]

Sean: I have been thinking that when the pyrolysis front advances "upwind",
against the draft, and that draft comes from below, it corresponds to the
same principles as both top lit updraft pyrolysis and reverse downdraft. The
draft carries smoke, generated between the pyrolysis front and the charcoal,
across the hot char to the flame. If FG chooses to top light his device, he
will get some of this effect. The more he controls his superficial velocity
(Source - PDF <http://www.woodgas.com/Superficial%20Velocity.pdf>), the more
benefit he can get from this effect. When FG tops off his fuel after the
initial batch burns down, needed b/c the retort is still putting out
woodgas, I am certain that won't conform to the same effect. Only a toplit
"stage 1" is a candidate. Superficial velocity effects the the pyrolysis gas
temp as it closes in on the charcoal. ie slower SV is going to crack more
CO2  until its too slow to keep the flame above the red hot charcoal burning
hot enough to radiate down to push the pyrolysis front (advancing upwind,
away from the charcoal). OK my head hurts now. -philip

On Tue, May 27, 2008 at 10:00 PM, Sean K. Barry <sean.barry at juno.com> wrote:

>  Hi Kurt, Philip, Tom, Terra Preta List et al.,
>
> There is one caveat which should be mentioned, I think.  This statement
> below refers to equilibrium reactions that occur when pulling the hot
> combustion gases past hot charcoal.  Usually this is only done in a
> down-draft gasifier.  A TLUD is not a down-draft gasifier.  In an updraft
> gasifier the heat is at the bottom and the fuel load is above, so the gases
> are rise up through successively colder biomass particles.  The equilibrium
> reactions do not occur.  Now, which is occurring in Folke's upside down
> downdraft gasifier?  Are hot combustion gases pulled through hot charcoal or
> through the cold fuel load?
>
> Regards,
>
> SKB
> ----- Original Message ----- *From:* Sean K. Barry <sean.barry at juno.com>
> *To:* Kurt Treutlein <rukurt at westnet.com.au> ; Philip Small<psmall2008 at landprofile.com>; Thomas
> Reed <tombreed at comcast.net>
> *Sent:* Tuesday, May 27, 2008 11:41 PM
> *Subject:* Re: [Terrapreta] new address to the simple kiln
>
>  Hi Kurt,
>
> Yes, Philip with one 'l' is correct.  I am wrong.  Here is a quote from
> "The Encylopedia of Biomass Thermal Conversion", page I-14 ...
>
> A series of reactions involving carbon, hydrogen, and oxygen are highly
> endothermic above about 500C;  in these reactions *the initial combustion
> products H2O and CO2 are reduced to form the fuel gases H2 and CO2*
>
> 7 cents ... $50
>
> Regards,
>
> SKB
>
>
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-- 
Philip Small, RPSS
Land Profile, Inc. * PO Box 2175 * Spokane, WA 99210
509-844-2944 cell * 509-838-4996 fax * 509-838-9860 office
Profile: http://www.linkedin.com/in/philipsmall
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