er, what again, about side feeding... ??? On Dec 22, 2010, at 3:56 PM, [email protected] wrote:
> On Wednesday 22 December 2010 00:06:35 Crispin Pemberton-Pigott wrote: >>>> That means training people not to do what comes >>>> naturally (let the stove die out and refuel and relight from >>>> scratch). >> >> Yeah. That is what I meant. > > ...and that's where I saw a point for confusion. > > It could read as letting the fire die out and then refuel being what comes > naturally. > > In fact what comes naturally is to dump another batch of fuel on top of > the glowing embers, this quenches any existing flame as the new load > heats up and subsequently the new load starts pyrolysing with insufficient > temperature or flame to burn the offgas. > > Pellet stoves get around the problem by feeding in a small amount of fresh > fuel such that a continuous flame is maintained over the whole firebed. > Everything has to pass through the flame. > > As a tlud maintains a fairly constant power if the primary air is well > controlled then extended burn time can be got by increasing the height of > the fuel. > > As this is often not practical there are a number of ways people have > tried to get around it. Paul Anderson went for fuel cassettes that were > pre loaded and alternated but it has not been mentioned recently. > > Top lighting for a clean start has been advocated by many, I think the > masonry stove association mentioned it when [stoves] was young. TLUD is a > special case where the progressive descent of the pyrolysis front > provides an air free offgas that shields the char formed above from > combustion. Change the conditions slightly by slowing the front or > increasing the air supply and this char is consumed. I've seen no mention > of particulates under these "no residual char" conditions. Generally > particulates are formed in the secondary combustion area. From a long > term health point of view particulates remain the bigger problem over > straight thermal conversion efficiency. > > Richard asked: >> Please tell me why adding a side feed feature to this stove would not >> greatly improve the cool down start up problem /smoke/ you are >> experiecning with your batch feed process ? > > Richard I don't know this stove, as Crispin has pointed out a modification > made to steam locos was to auger a "molehill" of coal from under the > firebed so the curtain of fire wasn't disturbed by a fresh cold batch of > coal being dumped on it. > > Given we seem to be looking at 5kW stoves, that's about 1kg of drymatter > per hour. What does one of your holey briquettes weigh when dry? Part of > the way a tlud works is to do with the change in buoyancy of the gases as > they evolve and then heat up. As we have discussed before I'd like to try > making a semi continuous burner using holey briquettes in much the same > way a rocket fuel in fed by pushing longer sticks into the fire chamber. > As I see it we need to keep it as close coupled as possible because with > these small devices if heat is lost in the primary combustion zone then > the gases in the secondary zone have lost temperature and are diluted by > CO2 and N2. The tlud avoids this problem by minimising the combustion > products of char. > > AJH > > > > > > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > Stoves mailing list > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > for more Biomass Cooking Stoves, News and Information see our web site: > http://www.bioenergylists.org/ > [email protected] > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address Stoves mailing list to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/ [email protected] http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
