Re: GAS-L: Air is Number 1!

[LINVENT@aol.com]

In a message dated 5/24/02 5:53:43 AM, tombreed@attbi.com writes:

<< 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. >>

Dear Stovers,
    Some time ago, I used the principal which Tom Reed described in building 
a small stove for my mine cabin. A couple of criteria were the design basis, 
one it would accept large wood, 2 ft. in length, and the other was that the 
exhaust had no smoke. I accomplished both with a 55 gallon heavy walled drum 
with an air preheater and injection of air at the right points. The gases 
would combust in the exhaust pipe with an adjustment in air inlet at that 
point and there was no smoke. It would run all night on one charge and keep 
the cabin nice and warm in the coldest periods- to minus 20˚F. 
    I used a hand cranked auger to discharge the ash. No grate. 
    Anyhow, sometime when it is possible to figure out how to make money on 
this type of system, perhaps I will market it. 


Sincerely,
Leland T. Taylor
 President
 Thermogenics Inc. 
7100-2nd St. NW, Albuquerque, New Mexico 87107 
phone 505-761-5633 fax 505-341-0424
Attached files are zipped and can be decompressed with <A 
HREF="http://www.aladdinsys.com/expander/";>www.aladdinsys.com/expander/ </A>

-
Gasification List Archives:
http://www.crest.org/discussion/gasification/200202/

Gasification List Moderator:
Tom Reed, Biomass Energy Foundation,  Reedtb2@cs.com
www.webpan.com/BEF
List-Post: <mailto:gasification@crest.org>
List-Help: <mailto:gasification-help@crest.org>
List-Unsubscribe: <mailto:gasification-unsubscribe@crest.org>
List-Subscribe: <mailto:gasification-subscribe@crest.org>

Sponsor the Gasification List: http://www.crest.org/discuss3.html
-
Other Gasification Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon