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: [email protected] > > To: [email protected] > > 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: [email protected] > > > > [mailto:[email protected]] 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 > > > > -------------- > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > Gasification mailing list > > > > > > > > to Send a Message to the list, use the email address > > > > [email protected] > > > > > > > > to UNSUBSCRIBE or Change your List Settings use the web page > > > > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.b > > > >ioen erg ylists.org > > > > > > > > for more Gasifiers, News and Information see our web site: > > > > http://gasifiers.bioenergylists.org/ > > > > > > > > > > > > > > > > _______________________________________________ > > > > Gasification mailing list > > > > > > > > to Send a Message to the list, use the email address > > > > [email protected] > > > > > > > > to UNSUBSCRIBE or Change your List Settings use the web page > > > > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.b > > > >ioen ergylists.org > > > > > > > > for more Gasifiers, News and Information see our web site: > > > > http://gasifiers.bioenergylists.org/ > > > > _______________________________________________ > > Gasification mailing list > > > > to Send a Message to the list, use the email address > > [email protected] > > > > to UNSUBSCRIBE or Change your List Settings use the web page > > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioen > >ergylists.org > > > > for more Gasifiers, News and Information see our web site: > > http://gasifiers.bioenergylists.org/ > _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
