Jim, Look at the Munchkin line of boilers. I am quite sure they do this.
Stephen -----Original Message----- From: jim mason <[email protected]> To: Discussion of biomass pyrolysis and gasification <[email protected]> Sent: Mon, May 16, 2011 2:08 am Subject: [Gasification] pre mixed boiler secrets? some new boilers drive premixed fuel/air into the combustion chamber hrough a single blower. this premixing of the charge improves the ombustion efficiency and cleanliness. i've found similar benefits of remixing fuel/air into the swirl burner on our gasifier. however, things got more difficult recently when we started returning o blowers. with the ejector architecture, you have a very high elocity section that the flame cannot back up through. with a remixed blower, the gas/air velocity is much slower and it is much asier for the flame to back up into the blower. which brings me to my question: does anyone know how contemporary remixed boilers are keeping the flame out of blower? in principle, it seems you have three methods to chose from 1. keep the mixture outside the flammability limits of the fuel . keep the gas/air velocity faster than the flame front of the fuel . keep the temp below the autoignition pint of the fuel 1 is unattractive as it requires a multistage mixing solution. 2 we've made work, but it is fussy, and requires a rather consistent low rater lest your "constriction" size get out of spec. also, when ou are working with blowers for a gasifier, the main problem is to et to adequate pull vac, so canceling some of this by pushing through constriction is not attractive. 3 we have not played with much. but it seems likely that a long oneycomb section might give adequate heat dissipation to quench a lame pass through. or maybe just a steel wool packed in the tube. we can of course go design this from scratch, but it likely has lready been well explored and solved in premixed boiler applications. anyone know how they do it? any related prior art on flame arrestors hat we might consider? j - ----------------------------------------------------------------------------- im Mason ebsite: http://www.whatiamupto.com urrent 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: ttp://lists.spaceship.com/listinfo.cgi/icp-spaceship.com _______________________________________________ asification 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 ttp://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: ttp://gasifiers.bioenergylists.org/
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