[Stoves] Insulation and stove life

Tue Jun 18 18:48:06 CDT 2013

Kevin,

You write:

*In Paul O's case, where he is interested in char making, I would guess
that most of the siliceous components would remain embedded within the char
particles, in a safe and non-hazardous manner. However, some ash particles
would be liberated in that some of the char would be burned in the
pyrolysis process. *

Does char get "burned" in the sense of being fully oxidized? I do not think
that this should happen under normal operating conditions. If the biomass
is uniform and if channeling does not occur, then there should not be
pockets where char has been reduced to ash. This only happens when too much
oxygen is supplied in one particular area of the reactor, as when
channeling occurs. When this happens the reactor wall gets extremely hot,
and CO2 is emitted at some of the burner holes.

That is why I believe that it is most helpful to work with a burner that
has a series of burner holes. *If CO2 is being generated, the operator
spots this in an instant.* I did not make a single change to the original
burner design that I inherited from Belonio. Any attempt to change the
diameter of the holes or distance between holes did not work at all. But I
did figure out how to scale up his burner design for much larger reactor
diameters.

The Belonio burner forces all of the syngas to the outside of the burner.
This is very important. This makes it easy to supply secondary air all
along the periphery of the burner. This I accomplished by means of a
housing that horizontally forces air into the vertically rising jets of
gas. Until I added a burner housing, all that I got out of the Belonio
burner was a long diffusion flame. With the housing, all of the flameletts
stay neatly under the pot.

Thanks.

Paul

On Tue, Jun 18, 2013 at 9:08 PM, Kevin <kchisholm at ca.inter.net> wrote:

> **
> Dear Crispin
>
> ----- Original Message -----
> *From:* Crispin Pemberton-Pigott <crispinpigott at gmail.com>
> *To:* 'Discussion of biomass cooking stoves'<stoves at lists.bioenergylists.org>
> *Sent:* Friday, June 14, 2013 6:37 PM
> *Subject:* Re: [Stoves] Insulation and stove life
>
>  Dear Kevin****
>
> ** **
>
> I think it is pretty obvious that a fan-powered stove will loft a lot more
> small particles than a natural draft version. They can easily be blown up
> through the fuel bed. If it is chimney-type ND stove then it is not such an
> issue.
>
>
>
> # Agreed. However, the big thing is the need for test work to quantify the
> nature and extent of such particles. A forced draft system that puts a
> large quantity of the small particles into the atmosphere of the Living
> space is certainly a problem.
>
>
>
> Best wishes,
>
>
>
> Kevin
>
> ** **
>
> Regards
> Crispin****
>
> ** **
>
> ** **
>
> *++++++++*****
>
> ** **
>
> Dear Crispin****
>
>  ****
>
> Thanks very much for your helpful comments. ****
>
>  ****
>
> Clearly, a chimney that vents products of combustion outside the Living
> Space is advantageous, compared to a stove system that vents into the
> Living Space. ****
>
>  ****
>
> I was aware of the great importance of the size of the Particulate Matter.
> Basically, "big dirt particles" are not nearly as bad as are fine particles
> that can lodge deep in the lungs. Clearly also, "more bad-sized particles",
> with "bad type composition", are worse than fewer "safer sized particles",
> of "relatively neutral composition.****
>
>  ****
>
> The only way to "digitize the generalities" is with a scientifically sound
> test program that identifies and then measures the relevant parameters.
> Once numbers have been attached to the relevant parameters, then it is
> relatively easy to determine whether or not a given stove system is "safe"
> or "hazardous."****
>
>  ****
>
> Rice Hulls are very interesting. While they have a high percentage of
> highly siliceous ash, complete combustion could potentially make the ash
> available in a hazardous manner.  In Paul O's case, where he is interested
> in char making, I would guess that most of the siliceous components would
> remain embedded within the char particles, in a safe and non-hazardous
> manner. However, some ash particles would be liberated in that some of the
> char would be burned in the pyrolysis process. ****
>
>  ****
>
> Best wishes,****
>
>  ****
>
> Kevin****
>
> ------------------------------
>
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-- 
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam

Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
http://www.esrla.com/
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