[Gasification] FUEL SELECTION TO GASIFIER

[jim mason]

leonard, as you are likely starting to figure out, the promise of
gasification is that "any waste biomass" can be used as fuel.  the
reality is that only biomass in very specific shapes, sizes and
moisture contents will work in very specific and related gasifier
designs.

this is always the rub in most gasification efforts.  the fuel must be
standardized.  like gasoline must be standardized for the engine, so
must solid fuel be standardized for the gasifier so it can make a
standardized gaseous fuel for the engine.  there are various fancy
designs around this problem, for which most of us have some scheme to
solve, which i do too, but i'm in the process of patenting it, so no
show just quite yet.

nonetheless, i find doug a little too pessimistic on fuel limitations.
 i think this mostly follows from his focus on imbert type, multi air
inlet, closed top gasifiers.  as well as his focus on gasifiers that
really work for long use installations.  which is good, of course, but
most of us here are learning, and compromised function and/or out
right failure can be very helpful during such.

open top stratified downdrafts, or closed top versions with monorators
are much more forgiving of water content.  (links can be provided if
these terms are unclear.)  and there are lots of options for making
more odd shaped fuels work using agitators or different hearth and
hopper configurations.  but most of them involve some added difficulty
or learning.  so in the beginning, repeated whacks to the side of the
gasifier with a stick, or some stirring of the hopper can often do
wonders (as well as cause problems).

but yes, wood blocks are sure to work.  so are wood pellets from the
store, run in a stratified downdraft.  (but be sure to fill with char
first).  many wood chips will too.  particularly the chips/chunks out
of a chipper/shredder that has a mesh screen at the output, so things
have to go round and round in the shredder/hammermill before they come
out.  my current theory (untested as of yet) is that such
chipper/shredder combinations will produce a  much better gasifier
fuel than a raw chipper.  see the standard "troybuilt" type
chipper/shredder for lawn/garden/yard applications.  i just found one
at the local second had store that i'll try out this week hopefully.

you can build a basic stratified downdraft in a weekend.  see here:
http://whatiamupto.com/Gasification/firstfiring.htm.  don't try to
drive across the country on this.  but to fast build and see it work,
you don't need much.  then improve from there.  seeing one work is
worth 5 books of reading.  (well, read the books too.  buy most of the
BEF library)

and yes, your life may never be the same.  like a computer user that
learns there is an operating system and application stack under their
computer screen, so is the pyro who learns there is pyrolysis and
gasification under fire.  you have been warned . . . ;-)

if you want to burn sawdust and cardboard without agitators or other
fancy configurations, you just can build an updraft.  it will be too
tarry to run in an engine, but you can make fire and/or run it into a
boiler/heater of some type.  it is really little more than a skinny
tank with an air hole on the bottom and a gas offtake on the top.  see
here: http://whatiamupto.com/Gasification/quadrafier/index.html.  it
could not be easier.

so in short, i suggest just starting.  gasification has hundreds of
opportunities for naysaying, but most of them are solvable once you
start.  none of them are solvable before you have begun.

enjoy the rabbit hole . . .

j






On 3/5/07, Leonard Hoke <phreejams at hotmail.com> wrote:
> Howdy Y'all,
>
> I've got about an endless supply of corragated cardboard and kiln dried
> sawdust(hardwoods) from a local furnitue plant. I've read all the articles
> that Jeff Davis has put out about paper, sawdust and charcoal fireballs, but
> have not seen anything on corragated cardboard.
>
> Anyhow the sawdust is what really has me excited. I would like to go on the
> design based on Doug Williams Pioneer, simply because from what I've read it
> works well for a beginner. The sawdust seems to be the challenge, so I'm
> asking for direction with the sawdust as fuel. What type of gasifier would
> work best?
>
> Thanks,
>
> Leonard
>
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