<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Arial; font-size: 12pt; color: #000000'>Dean:<br><br> My preferred option is to kill the activity when the pyrolysis front reaches the bottom. The resulting char should mostly be heading for use in soil as biochar (after suitable preparation - maybe for water cleanup, etc).<br><br> But you already know that some of us concerned about climate issues will be saying this.<br><br>Ron<br><br><hr id="zwchr"><b>From: </b>"Dean Still" <deankstill@gmail.com><br><b>To: </b>"Discussion of biomass cooking stoves" <stoves@lists.bioenergylists.org><br><b>Sent: </b>Sunday, September 23, 2012 6:10:45 PM<br><b>Subject: </b>[Stoves] Purple flame<br><br>Hi Stovers!<div><br></div><div>I've been noticing a shift from blue flames above the burning bio-char in a TLUD to purple flames nearer the end of the burn when the bottom of the pile is glowing bright orange. I suppose that the blue flame is caused by burning CO but I wonder why the purple forms after the blue? The blue self sustaining flame doesn't heat the water in the pot as well as the purple flame phase although the pile of bio-char is fully ignited at that time and may account for the more rapid rise in water temperature.</div>
<div><br></div><div>Any ideas?</div><div><br></div><div>Best,</div><div><br></div><div>Dean</div>
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