GAS-L: Fw: Air is Number 1!

["Tom Miles" <tmiles@trmiles.com>]

From: "Paul S. Anderson" <psanders@ilstu.edu>
Cc: "gasification" <gasification@crest.org>
Sent: Friday, May 24, 2002 6:26 PM
Subject: Re: Air is Number 1!


> Tom R, Tom M, and all,
>
> Tom R's message is left below for reference.
>
> First, I agree that we start with the principles!!!!!!!!   And all of the
> principles I know about stoves and gasification I learned from Tom Reed,
or
> on the Stoves list, or a little at Boy Scout camp.
>
> Second, Tom wrote:
> >  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?)
>
> No, they are NOT the same.
>
> Structure (physical structure) of a stove includes things like legs, and
> oven, and plancha, and pot-insert holes, ventilation that is not primarily
> for increased draft, and where you place the combustion chamber.
>
> The combustion chamber is where the burning takes place.  And therefore,
> the construction of the combustion chamber DOES include the issue of how
to
> get the air into the right places at the right time in the right amounts.
>
> Physical structure and combustion chamber are VERY DIFFERENT, but we must
> be aware of one as we develop the other, or we will get into trouble
quickly.
>
> I believe there is no confusion about what is meant by "fuel" and by
> "cooking" as being two other components for consideration when doing stove
> development.
>
> Back to the issue of "air" and Tom's statement that "AIR CONTACT IS THE
> MOST IMPORTANT PART OF STOVE DESIGN".   I agree!!!!!!!!
>
> But that air contact takes place where?  It takes place in and around the
> combustion chamber.
>
> However, as I think further about air, I realize that all air is NOT the
> same.  The air in Illinois (650 feet above sea level, humid in summer) and
> the air in Denver (5200 feet ASL and "Denver dry") are not the same air.
>
> Also, a unit of preheated secondary air at 400 degrees F is not the same
> air as the exact same molecules as a unit prior to being preheated.
>
> Now the question is:  Do we as stove designers make an issue of "aires"
> (plural) like we make an issue of "fuels" (plural)?  Or can the
"combustion
> chamber" attributes actually incorporate the issues about "air" being
> pre-heated or fan-forced or something?
>
> Let us not neglect the importance of air.  Air is like fuel:  If either
air
> or fuel is absent, there will not be any combustion.  Now THAT is a
> principle!!!   (See, Tom, you have taught me well.)
> (Smile).
>
> Well, I just now thought that I should modify my list of components to
become:
>
> combustion materials (fuels and air)
> combustion chamber (generating energy from the combustion materials)
> structure (holding together the physical parts in a usable way)
> cooking (getting use from the "stove", such as pot-configurations for
> socially-defined methods of cooking, to also include space-heating if
needed)
>
> Please let me re-phrase those 4 components:
>
> stove combustion materials (fuels and air)
> stove combustion chamber (generating energy from the combustion materials)
> stove structure (holding together the physical parts in a usable way)
> stove cooking (getting use from the "stove", such as pot-configurations
for
> socially-defined methods of cooking, to also include space-heating if
needed)
>
> I hope that this has helped clarify why I have separated the issues of
> stoves development
> into 4 components.
>
> Interestingly, those of us on the Stove list serve have our own
specialties
> in the 4 components.  Many are combustion chamber specialists.  Others are
> fuels people.  A smaller number are into the structure issues.  And a few
> (anybody??) on the Stoves list are focused on the cooking issues.  And yet
> we all seek "stove" improvement.
>
> Have a good weekend !!
> (or if you do not read this until you are back at work, I hope you had a
> good weekend.)
>
> Paul
>
> At 05:28 AM 5/24/02 -0600, Tom Reed wrote:
> >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 had better start with the principles.
>
> Paul S. Anderson, Ph.D.,  Fulbright Prof. to Mozambique 8/99 - 7/00
> Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL  61790-4400   Voice:  309-438-7360;  FAX:  309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>
>
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