[Gasification] Sawdust in Fan TLUD

Sat Jun 4 18:14:12 CDT 2011

I have pelletized and i know how it works.
It is o.k. as long as you have good clean sawdust at a reasonable price.

The thing is most people don't !

I make chips from brushwood and treetops at a reasonable price.
The chip quality is a bit mediocre, though and I want to refine it so as to 
keep it from bridging. Cut the long bits short and make it look more round or 
square, then it will flow !
I am happy with a density of 400 kg/m³ instead of 650 for pellets as long as i 
don't have to ship them far away.

If torrefaction wasn't so expensive at small scale, it would be a good 
solution.

Rolf

Am Samstag, 4. Juni 2011 23:39:42 schrieb Art Krenzel:
> Rolf,
> 
> I do not know why other machines like it were never made.  That was the
>  only machine of that design I have ever seen.  I think the quality of the
>  end product pellets did not make it through the long distance, multiple
>  handling systems sufficiently well to meet the needs of the end user. 
>  They were sort of "heavily squished" rather than extruded with a melted
>  lignin total outer coat.  This left the pellet much more susceptible to
>  handling damage.  The process was operated in full recycle mode until the
>  gears heated up before any product was made to facilitate the heat
>  pressing of the sawdust.
> 
> I would seriously review using a hollow cylinder with a piston to compress
>  the sawdust.  It does not do well in the "rock in the sawdust" test. 
>  Most, if not all, pelletizing processes need alot of cleanup of the floor
>  area with brooms and shovels used by minimum wage help.  This swept up
>  material is normally added to the feed side of the system and could cause
>  serious maintenance difficulties.  The gears were spring loaded and just
>  bounced open sufficiently to pass any incompressible foreign matter.
> 
> The gear pelletizer system was incredibly quiet.  The loudest noise came
>  from the auger and the loader (when it was running).
> 
> Art
> 
> > From: energiesnaturals at gmx.de
> > To: gasification at lists.bioenergylists.org
> > Date: Sun, 5 Jun 2011 00:16:15 +0200
> > Subject: Re: [Gasification] Sawdust in Fan TLUD
> >
> > Art,
> > this sounds very close to what I want to do and I cannot find it done!
> >
> > I want to make pellets without having to pelletize.
> > After my very good experience with almond shells ( m/l 30 x 20 mm)
> > passing readily through 3 and 3.5 " (75 and 90 mm) spiral augers and
> > around bends, I want to stamp wood chips on a rotating cilindrical die
> > into " coins" of some 15 -20 mm diam.
> > I imagine some kind of hollow cylinder with holes and a matching,
> > synchronized cylinder with short hardened steel punches stamping the
> > chips thru those holes .
> > The stamped chips fall out of the hollow die and what has not been
> > stamped runs around for another chance...
> >
> > Why does this machine not exist ?
> >
> > Rolf
> >
> > Am Samstag, 4. Juni 2011 21:19:26 schrieb Art Krenzel:
> > > Pete,
> > >
> > > Have you looked into gear compression pelletizer? Several years ago at
> > > the Port of the Tri Cities in Oregon, I saw a sawdust pelletizer made
> > > of two large gear wheels (about 18 inches in diameter) which were
> > > heavily spring loaded together and driven by a highly geared down
> > > electric motor. I believe only one gear wheel was driven with the other
> > > acting as an idler. They acted as a "nip roller" in the real world.
> > > They formed a semi solid pellet about two inches long and about 5/8
> > > inch in diameter.
> > >
> > > Sawdust was augured to a hopper above where the gear wheels meshed and
> > > self fed into the gears. The gear faces measured approximately two
> > > inches wide.
> > >
> > > The pellets were not of the same high density as the extruder
> > > pelletizers make but if your purpose is only to use the straw on site,
> > > this might work for you. They were handling the pellets with a bucket
> > > loader and auger. Some of the pellets broke down in handling but the
> > > bulk of them remained in good shape.
> > >
> > > It was simple, quiet and did not have a very large electric motor
> > > driving it.
> > >
> > > Art Krenzel
> > >
> > > > -----Original Message-----
> > > > From: gasification-bounces at lists.bioenergylists.org
> > > > [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of
> > > > Pete & Sheri
> > > > Sent: Friday, June 03, 2011 9:01 AM
> > > > To: 'Discussion of biomass pyrolysis and gasification'; 'Thomas Reed'
> > > > Cc: 'Hugh McLaughlin'
> > > > Subject: Re: [Gasification] Sawdust in Fan TLUD
> > > >
> > > > Could one possibly semi-pelletize the sawdust directly at the input
> > > > to the gasifier? I see pellet makers that use a screw extrusion
> > > > method. If one could get enough compaction to loosely hold the
> > > > particles together, right at the input point, then there wouldn't be
> > > > the "spouting" discussed previously. There also wouldn't be all that
> > > > pressurized air to deal with. The compacted material would also
> > > > create a "seal" between the gasifier and the outside world, if
> > > > needed.
> > > >
> > > > Pete Stanaitis
> > > > --------------
> > > >
> > > >
> > > >
> > > >
> > > >
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