On Sun, Nov 28, 2010 at 7:09 AM, Greg Manning <[email protected]> wrote:
> OK, First off, Greetings List(s)! > > Second: > > Since my accidental discovery of smaller feedstock sizes about a week ago, > I've been doing some tests (ok, mad scientist stuff), to the acceptable > "Minimum" size level in my downdraft units. > > For those that do not know me, briefly, I build smaller downdraft > gasifiers (under 250KwT) I do NOT go bigger than that, I have my reasons. > > I've been using a "standard" sized woodchip, typical of most small > industrial units (NOT your home "shredder/mulchers") generally 15-30 hp > units. > > These chippers produce, for the most part, chips about 3 x 3 x 0.25 cm > chips (3/4 x 3/4 x 3/16") and down to the point of dirt, or mash. > > 6 - 7 years ago, I had settled on a rotary screen design using a "fines" > screen of 0.63 x 0.63 cm (1/4 x 1/4") square openings. this has been my > "smaller" size since then. (Until this week, we have always discarded > anything that was considered "fines", used these as mulch or horse bedding). > > Upon the somewhat accidental use of a fines pile as feedstock, much to my > surprise, the unit accepted the fines for the most part, for about 8 hours > of operation, (these where raw fines, directly from under the rotary drum), > Yes the gasifier did eventually plug up and shut down BUT, not knowing what > was going on at the time (I did NOT know the unit was running on fines) I > was perplexed as to what had caused the problem, upon investigation, and > finding that the worker had inadvertently used this pile, instead of the > correct one, and finding out the length of the time the unit had ran on > them, I undertook the new question of "how small I can go" in feedstock > sizes. > > As it turns out, the unit will run consistently on a much smaller chip size > than originally thought. We have since changed the fines screen in the > rotary screener to 3/16" round holes (punched panel) on an offset pattern > (68% opening) the ratio change is as follows: > > Original 1/4 x 14" square openings, ratio of fines to acceptable feedstock > 30% fines, 70% feedstock > > New 3/16" round openings, 10 - 13% fines, 87 - 90% acceptable. > > Hoping that this information is useful to someone. > Kindest regards: > > Greg Manning, > Canadian Gasifier Ltd. (www.cangas.ca) > Building Hi-Performance Gasifiers, Since 2001 > > Brandon, Manitoba, Canada > 1 (204) 726-1851 > > > > _______________________________________________ > 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/ > >
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