[Default] On Thu, 4 Apr 2013 21:52:25 -0600,Ron <[email protected]> wrote:
>Julien > > I am quite certain the problem is in your statement: > > "I put the can on top a paint-can lid which blocked off all >> >> primary air." > > It was not Crispin's intent that you operate that way, only that you have > full control over the quantity of primary air.. In your run, "primary" air > was reaching eventually all the way to the bottom by coming through the > secondary air circular gap. You were always producing CO2, not CO and H2. Ron and Julien, Even if all the air entering the bottom is choked off there is enough air in the dried stem to allow pyrolysis and then combustion of the fresh char, given the heat losses the combustion can continue at a low temperature and never reach the spontaneous combustion temperature of the offgas. This is one reason why straw fires are so difficult to put out. Again because the combustion temperature is low the products of combustion are CO2, steam and PICs. As Ron says later generating CO2 ( and steam) at the combustion site causes dilution of the offgas, gases tend to have a limited range of mixture in air to support a flame below their spontaneous ignition temperature, so when diluted the cold "smoke" will not support a flame nor burn without smoke. IIRC also that Tami suggested sooty PICs were difficult to burn out once formed. _______________________________________________ Stoves 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/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
