[Bioconversion] Re: Fireballs, Gasifiers and Heathuts

[Jeff Davis]

Dear Tom,

Tom wrote:
>When we tried real army waste in the disposal the plastic clogged it up
as >you also found.  There is a >company in Tennessee that makes "MSW
fluff".  >We have a cubic meter of it for testing.  I notice that there
>are chunks >of plastic that they haven't quite mastered.


I wonder if plastic could be charred in a retort.


Tom wrote:
>Tell me more about how the paper fireballs burned.  Your picture makes it
>look >rather anemic.  I >suppose the thermal conductivity of low density
>paper >fireballs can cause pyrolysis to occur, >leaving char at each
>level, so hard >for the fire to propagate.


I have burned three types of fireballs:

CHARCOAL/SAWDUST FIREBALL: Started by placing in heathuts combustion
chamber then removed for observations. Right now I make fireballs more
like a cook not as much as a scientist; "a pinch of this and a pinch of
that". But I would estimate 20% sawdust, 5% starch (un-boiled) and 75%
charcoal. It's been many years ago that I had a charcoal briquette (store
bought) grill but I would say it burned much like the store bought
charcoal briquette. I do not recall a flame; maybe there was one in the
beginning. One could say that this fireball is a little shy. When it's
burning a person might make a mistake and try to pick it up. It doesn't
look like it's burning but it is. One only needs to blow on it or fan it
some and it comes to life. When fanned the fireballs looks more like a
glowball, not a fireball. The ash easily sheds it's self when fanned
reviling the glowing combustion. If left un-fanned it will continue to
consume it's self in combustion. As of yet, I have not burned any
fireballs in groups, only one at a time.

NEWSPAPER FIREBALL: Started with a lighter. This fireball burned much like
the charcoal/sawdust fireball. But its inflammability was much greater, at
least in the beginning. After the flame died out the newspaper fireball
was similar to the charcoal fireball. Also when I would press down on the
fireball it proved to be strong, did not crumble. I pressed with a small
stick, the size of a match (wooden). This fireball is on the smoky side.
My camera skills are on the poor side and I was not able to show the
interesting flame that the newspaper fireball had in the first part of
combustion. Kind of a long flame, yellow the tallest and blue off to the
sides (as I remember). If only a small part of this fireball is burning,
it will eat a hole into it’s self.

NEWSPAPER/SWITCHGRASS FIREBALL: Started with a lighter. Maybe 45%
switchgass. This was the smokiest. It also was fragile once the flame was
out and it was in the glowing combustion stage. Did not seem like it would
make good gasifier fuel. The fanning would blow it off the table and it
would brake easy. The switchgrass was not in fine particles. It was dry
(field dry) and ran through the disposal. The disposal did not seem to
like this. It was cut up in to about 1/2" pieces.



The real test will be when I can build that stratified gasifier and give
them a real test!



-- 
Jeff Davis

Some where 20 miles south of Lake Erie, USA