[Gasification] now for something really boring...

[Ray Menke]

I interpreted this relative to some of my experiments with an "anila
inspired" stove/retort that I made from a 20 pound propane bottle.  A
cylinder down the middle is where the fire takes place.  Dry wood
chunks/chips/biomass are loaded into the outer cylinder through a
porthole, which is sealed and bolted down tight.  Then the whole
propane tank is wrapped in insulation, except for the top exit, and
the bottom cone/grate sitting on a blower.The material in this outer
area has no access to Oxygen as it is heated by the very hot walls of
the inner steel cylinder (with 1/4" thick walls) fed air by a blower
through 8 small 1/4 inch holes in a grate.  As the wood in the outer
insulated area is heated, the steam, gas, tars, etc, are directed
into the "firebox" by 4 small 1/4" holes, adding gaseous fuel to the
fire.. If I run the stove/retort (by adding blocks or chips at the top
of the inner cylinder) for only a couple of hours, I get beautiful
charcoal and torrefied wood.  If I run it at full blast for perhaps 3
hours, the whole 4 gallons of biomass is turned to charcoal.  (This is
not the same as the charcoal made in my TLUD stoves.)  Obviously, the
temperature next to the glowing firebox is hotter than the temperature
on the skin of the propane tank.
I could take advantage of this destructive distillation of wood by not
running the exiting products from the outer cylinder into the infernal
in the internal burn area, but to an external collection tank, and
then into the firebox.  (I just haven't figured out what I would do
with the liquids and tars.)
There are various drawings of the grates used in the Anila stove, but
my version (Anila inspired), with the blower, has only 8 holes.  (Good
advice from Crispin!) There isn't any smoke, but quite a bit of ash
blowing up out of the firebox with the flame.  (Nowhere for the ash to
go but up!)
I would imagine a solid hunk of wood would have a much different
R-value that loose chips with air space between them.  My porthole is
just large enough to reach into with the hands, so I could insert
larger chunks of biomass, but it would probably take much longer to
convert them to charcoal.

On Thu, Dec 23, 2010 at 11:15 PM, Greg Manning <a31ford at gmail.com> wrote:
>
>
>  Bruce, and List.
>
>  FWIW, construction wood (houses) has a rough R value of 1.2 per inch (so a
> 2 by 4 is about R 4.2 ( 3.5 X 1.2 )).
>
>  This is considered "kiln dried wood", air dried would be somewhat less,
> (say R 1) wet wood, way down, R 0.3.
>
>  Your observed effect of the outer surface of a chuck of wood is exactly why
> I only use wood chips for gasification, they do NOT have this effect, they
> instantly go from wood to charcoal (in under 1 second), they stay intact if
> the char state, and do NOT introduce tars and phenols farther down, in the
> process. chips are IDEAL for gasifier use.
>
>  Greg
>
> -----Original Message-----
> From: gasification-bounces at listserv.repp.org
> [mailto:gasification-bounces at listserv.repp.org]On Behalf Of Bruce
> Jackson
> Sent: Wednesday, December 22, 2010 7:58 AM

> Where can I look to see the experimental results of heat transfer through
> wood?
>
> I took to heart what folks said about destructive distillation. What I see
> in
> the stove, is that the wood isn't absorbing the heat as fast as the heat
> from
> the burning outer surface is making it. In other words the wood is both
> destructively distilling, and drying.
> It made me wonder what would be the optimal BTU input per pound (insulated
> container of course) for wet wood.
>
> Also I wonder does the BTU input vary after the moisture content changes?
> (this
> from distilling ethanol, you need higher temps at the end of a batch run to
> push
> the EtOH out of the remaining water) I was thinking about the center of the
> blocks being so well insulated by the remaining carbon that the water
> couldn't
> see the heat right away (or as fast as the water on the outer perimeter


-- 
Ray  Menke