On Sat, Feb 12, 2011 at 6:06 AM, john blount <[email protected]> wrote: > I have a gasifier (Fluidyne design) that works excellently with two inch > chunks of wood, but when we switched to burning briquettes (compressed > shavings and sawdust) everything changed so much that we no longer can > sustain gas production, plus have extreme amounts of slipped char and > cyclone particulates. > Has anyone experience in gasifying such fuel? > The swelling from steam in the hopper causes bridging that did not occur > with the chunks, but that should be easily overcome, perhaps with a > monorator hopper?
john, this is a hard problem, but there are some partial fixes that might get things to tolerable. it can likely be solved without a 50k extruder or giving up. the monorator will still keep your hopper with steam in it, so decomp will still start. not much win here. the biggest fix would be to move your hopper off the top of your reactor. go to an L type arrangement, with an auger, chain drag, or belt between them. this gets the raw fuel off the top of the heat, and keeps the steam out of the reactor. this is somewhat like a pellet stove, taht only feeds the compressed pellet fuel in as it is burned. if a pellet stove was straight gravity feed from an overhead hopper, they'd have the same problem you currently have. this "hopper off the reactor" architecture also prevents channels from the hopper to the coals, which is how one gets puff/explosions. once you get the hopper off the reactor the puff problem goes away. however, now you have a fuel transport problem, which is its own set of annoyances. the other two possible solutions are to stay with the over reactor hopper, but try to purge the steam. you can do this the russian method with a fan to pull it off, or the leak method where you all in a controlled amount of air into the hopper, which is pulled through tot he reactor, pulling the steam with it. this is the partial stratified downdraft scheme. or the tar flare idea, which i think you are running anyways, so maybe this isn't enough. of course not shutting down with briquettes still inside is helpful. the bad decomp happens when they site in the steam during shutdown. you are likely already doing this. or, you might consider adding a binder to the briquetting process. latex paint is seemingly a cheap and safe option. richard stanley of legacy foundation will have many others. still, of all these, i think the offsetting of the hopper from the top of the reactor will do the most. if you can keep the briquettes in good form until the hearth, they will behave much better in the hearth. but then again, if not lignin bonded, they might still decomp there. isn't gasification fun? what happened to the high resin block fuels? jim > Thanks, > John Blount > > _______________________________________________ > 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/ > > -- ------------------------------------------------------------------------------ Jim Mason Website: http://www.whatiamupto.com Current Projects: - Gasifier Experimenters Kit (the GEK): http://www.gekgasifier.com - Escape from Berkeley alt fuels vehicle race: www.escapefromberkeley.com - ALL Power Labs on Twitter: http://twitter.com/allpowerlabs - Shipyard Announce list: http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com _______________________________________________ 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/
