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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Paul,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The typical impact of higher CO2 is to reduce combustion temperatures and make producer gas combustion less stable. As dilution increases and temperatures decrease in upper regions I would expect to see an increase in unburned CO. You should be able to measure differences with a small probe and thermocouple. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Tom<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Stoves [mailto:stoves-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>Paul Olivier<br><b>Sent:</b> Thursday, June 27, 2013 5:04 PM<br><b>To:</b> Discussion of biomass cooking stoves<br><b>Subject:</b> Re: [Stoves] Ph.D. Thesis on TLUD Stoves.<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><div><div><div><div><div><p class=MsoNormal style='margin-bottom:12.0pt'>Ron,<o:p></o:p></p></div></div><p class=MsoNormal style='margin-bottom:12.0pt'>When char is consumed in a fan-powered TLUD, several negative factors come into play. At the point where char is consumed, hot zones are created, giving rise to temperatures that are truly brutal on all types of metal. As a consequence of such high heat, the walls of the reactor can be degraded in a matter of months, often times, in just a few weeks. <br><br>When char is consumed, the descent of the pyrolitic front is not uniform. The syngas generally contains a lot of CO2. An inefficiency in heat transfer is created as energy gets released within the reactor at a considerable distance from the pot. To compensate for this loss in heat transfer, the operator might increase the speed of the fan, and in so doing, make matters worse.<o:p></o:p></p></div><div><p class=MsoNormal>If syngas contains a lot of CO2, I wonder how this affects the combustion CO and H2 within the syngas. If CO and H2 are diluted with CO2, do they fully combust when exposed to secondary air? Is there a link between the presence of CO2 prior to the combustion of the syngas and the presence of CO after the combustion of the syngas?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal style='margin-bottom:12.0pt'>When char gets consumed, pockets of ash are created, and they might easily contain high levels of cristobalite. This is especially true in the case of rice hulls, which contain high levels of amorphous silica. When char gets consumed, the quality of the biochar produced is compromised. Ash is not biochar, and biochar is not ash.<o:p></o:p></p></div><p class=MsoNormal>Thanks.<o:p></o:p></p></div><p class=MsoNormal>Paul Olivier<o:p></o:p></p><div><div><div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p><div><p class=MsoNormal>On Fri, Jun 28, 2013 at 2:43 AM, <<a href="mailto:rongretlarson@comcast.net" target="_blank">rongretlarson@comcast.net</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Julien and list<br><br>1. Thanks very much for providing this cite. I have read most and find it to be a well done thesis. I wish we had more like it.<br><br>2. The concepts of char and TLUDs are in here thoroughly. But nothing on the idea of a stove designed to make char. All char is presumed and desired to be consumed. <br><br>3. My conclusion (would like to hear more) is that a good case is made (not intentionally) for NOT consuming the produced char in a TLUD (this one fan-powered and widely sold in India as the "Oorja" (started by BP)). Very little gain in overall efficiency as the char is consumed.<br><br>4. A major advance was his study of the importance of ash in this "char" period as a poor radiator - thereby responsible for (undesired) high char temperatures.<br><br>5. Most everything shown as a function of superficial velocity (Vs) - with 16-17 cm/sec shown as key dividing point in stove behavior.. Above which velocity one swtches from char production to char consumption. I have not seen this before.<br><br> For his highly automated fan system, measuring Vs was apparently not so difficult. Anyone able to give a way to get an easy estimate of Vs, when there is only natural draft?<br><br>6. Quite a bit on the importance of low emissions of CO.<br><br>7. Good information on both the experimental and computational side of top-lit (packed bed) stoves. Not much here for rocket stoves.<br><br>Have I got #3 right?<span style='color:#888888'><br><br><span class=hoenzb>Ron</span></span><o:p></o:p></span></p></div></div><p class=MsoNormal style='margin-bottom:12.0pt'><br>_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br><a href="http://stoves.bioenergylists.org/" target="_blank">http://stoves.bioenergylists.org/</a><br><br><o:p></o:p></p></div><p class=MsoNormal><br><br clear=all><br>-- <br>Paul A. Olivier PhD<br>26/5 Phu Dong Thien Vuong<br>Dalat<br>Vietnam<br><br>Louisiana telephone: 1-337-447-4124 (rings Vietnam)<br>Mobile: 090-694-1573 (in Vietnam)<br>Skype address: Xpolivier<br><a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a> <o:p></o:p></p></div></div></div></div></div></div></body></html>