Hi Brian, Boy does this sound familiar! I posted the same question about 3 years ago. I haven't seen Greg's response yet so maybe I am reitering but here is my take. First I would check to see how much tar is in your piping. If there is no tar declare victory and move on. This is what an UGLY tar flare looks like:
http://groups.yahoo.com/group/WoodGas/photos/album/118107394/pic/1187813934/view?picmode=&mode=tn&order=ordinal&start=1&count=20&dir=asc This made tons of tar. Yours looks a little better. What size and quantity of nozzles are you running? My first thought is to smash them flat or swap them out for smaller ones to increase your blast rate. You want the oxygen to penetrate to the centerline of the machine to burn any tars that are shielded by CO2. Next I would try reducing your nozzle tip diameter. I started with mine WAY to big. Bigger increases the amount of stuff pyrolizing thus making more tar gas for the amount of oxygen available to burn it. Tar gas is the "heating oil for reduction", but too much can gum up the works just like an overly rich home heating furnace. Lastly I would lower your nozzles closer to the restriction. Your temperatures look pretty good so you don't need much distance for reduction. I do everything above the restriction(yes, my rig is not the norm) and only run 14 inches for combustion and reduction. Stephen -----Original Message----- From: Brian and Cara Paasch <[email protected]> To: Discussion of biomass pyrolysis and gasification <[email protected]> Sent: Sat, Jul 24, 2010 10:08 pm Subject: [Gasification] Can't get to blue flare Hi all, We recently started testing our downdraft gasifier. So far we haven't been able o move from a yellow/red flare to a blue flare. I've searched the gasification rchives and as best I understand, we need more air running through our system. s that correct? We've increased the air over previous test runs but our flare s showing no sign of going from yellow to blue. As shown in this video: http://www.youtube.com/watch?v=9X6WPlhyOWc&feature=channel we have a pretty clean flare, no obvious smoke, but day or night, our flare is ost certainly NOT blue. Anything else we should be considering? Thanks! -brian PS Our wood moisture content is less than 15%. _______________________________________________ asification mailing list [email protected] ttp://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org ttp://gasifiers.bioenergylists.org ttp://info.bioenergylists.org _______________________________________________ Gasification mailing list [email protected] http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org http://gasifiers.bioenergylists.org http://info.bioenergylists.org
