Air is Number 1!

["Tom Reed" <tombreed@attbi.com>]

Dear Paul, Tom and All:

Tom Miles hits it on the head.  Phlogiston (oxygen) access is the most
important part of biomass combustion, gasification and stove design!
(Dephlogisticated air is the original name for the combustion gases exiting
your exhaust pipe, since the oxygen has been consumed, making a useful, hot,
non oxidizing gas.  Try it for pyrolysis.)

I have a commercial stove that is dreadful because the air enters at the
wrong places - too much at bottom (releasing volatiles and gases too
quickly), not nearly enough at the top, so gases aren't burned before they
reach their target, the pot being heated.  By rearranging the air holes it
burns beautifully inside the stove.

I find that most stove tinkerers tend to focus on materials of construction
first and principles last.  This needs to be reversed.  AIR CONTACT IS THE
MOST IMPORTANT PART OF STOVE DESIGN.

So, in stove design, first focus on the principles - how the pyrolysis will
occur, how the resulting gases will access oxygen, then worry about Paul's
four principles which are certainly also VERY important.

o  fuel
o  combustion chamber
o  physical structure
o  the cooking

(However, aren't combustion chamber and physical structure the same thing?)

Another MAJOR piece of the puzzle is water content (measured by weighing,
heating to 105C for an hour (depending on size), then reweighing.  Wood with
30% moisture (jungle wood) is barely related to wood with 7% moisture
(Denver Dry).

Combustion of dry wood requires 6 kg of air for each kg of wood.  For 30%
moisture wood it only requires 4.2 kg.  Pyrolysis of dry wood requires < 1
kg air/kg wood; for 30% moisture wood pyrolysis requires 2 to 3 kg air/kg
wet wood.

So, principles first, application second will get us to a new generation of
cookstoves!

Yours truly,                             TOM REED
BEF STOVEWORKS

PS:  I spent a day with Paul in Normal Illinois discussing all this and
seeing a battery of new kinds of stoves that he is making.  Very ingenious.
There's a lot of room for inovation in solving the world stove problem, but
it has better start with the principles.





----- Original Message -----
From: "Tom Miles" <tmiles@trmiles.com>
To: "AJH" <andrew.heggie@dtn.ntl.com>; <stoves@crest.org>; "Paul S.
Anderson" <psanders@ilstu.edu>
Sent: Thursday, May 23, 2002 10:04 AM
Subject: Re: Temperature dilution


> Paul,
>
> If you are reducing the problem to a few components you should include
> phlogiston, given to us in the 17th century by Johann Joachim Becher and
> popularized by Georg Ernst Stahl. Phlogiston is "the matter and principle
of
> fire, contained in all metals and combustible bodies, and given up in
> burning or calcination." (McCann, H. Gilman. Chemistry Transformed: the
> Paradigmatic Shift From Phlogiston to Oxygen. Norwood: Ablex, 1978.)
>
> There you have it all in one bundle.
>
> Tom
>
> ----- Original Message -----
> From: "Paul S. Anderson" <psanders@ilstu.edu>
> To: "Tom Miles" <tmiles@trmiles.com>; "AJH" <andrew.heggie@dtn.ntl.com>;
> <stoves@crest.org>
> Sent: Thursday, May 23, 2002 8:58 AM
> Subject: Re: Temperature dilution
>
>
> > 4.  I have previously written about the 4 components or issues of stoves
> > :  fuel, combustion chamber, physical structure, and the cooking
> > practices.  But Tom Reed recently argued to me when we met that a 5th
> > component could be "air".  I countered with a comment that "air is air"
> and
> > we assume it is available, and that the issues about air are really
within
> > the issues of the combustion chamber and how it treats and delivers the
> > air.  Air is essential, but I have not yet added it to the list of the 4
> > components.  (Your thoughts would be appreciated on this topic.)
>
>
>
>
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>
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http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
For information about CHAMBERS STOVES
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