[Default] On Sat, 23 Feb 2013 10:37:42 -0500,Alex English <[email protected]> wrote:
>Frank, Harold, > >Interesting discussion, made more so by the fact that I making drums of >char yesterday. > >Here is a paper that suggests that initial heating of coal has more to >do with H20 sorption than oxygen. Rank and particle size being other >factors. >Where upon oxygen moves to center stage. > >http://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/14_1_TORONTO_05-70_0059.pdf This weight gain being water was my first thought, but Frank said the oven was at 105C which I thought would militate against sorption of water, it is possible that as weak bonding forces will play a part in this hygroscopy that the water needs a higher temperature to drive it off and then the converse is true also. Sorption of water in effect takes vapour and turns it to liquid, giving up its considerable latent heat as it does so. Fresh char does seem to have an auto ignition point below 200C. Of course moist air ( as considered in the paper Alex cites) is a well known catalyst, hand warmers using a mixture of steel wool and salt are available and char will have mineral salts on the surface. AJH _______________________________________________ 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://www.bioenergylists.org/
