<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body data-blackberry-caret-color="#00a8df" style="background-color: rgb(255, 255, 255); line-height: initial;">
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Thanks Julien</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
That was very helpful. </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Prof Lloyd, can you assist us answering Question 3 below?</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Regards </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Crispin </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br name="BB10" caretmarkerset="INVALID" class="markedForCaretMarkerRemoval">
</div>
<br>
<div>
<div dir="ltr">
<div>Hello Rajan and all;</div>
<div><br>
</div>
<div>The point you raise about allowing for a few minutes of the char-burning phase to heat the charred fuel and drive off any left over volatiles is a good one.</div>
<div><br>
</div>
<div>The height of the TLUD combustion chamber is likely to be important, because the top of a tall column of charcoal may not get hot enough to drive off volatiles by char-burning. In addition, the top of a tall column will have experienced a longer time for
tars to condense during the flaming-pyrolysis phases than a shorter column. I have made some grimy wood-pellet biochar in a stove pipe TLUD.</div>
<div><br>
</div>
<div>Not driving off the volatiles will result in fine pore space of the biochar being occluded. Perhaps that is what was going on with the following research:
<p><font face="Tahoma"><font face="Tahoma">Peterson, S. 2013. Comparison of gasification and pyrolysis methods for preparing biochar from corn stover and wheat straw.
</font></font></p>
<p><font face="Tahoma"><a href="http://biochar.illinois.edu/Peterson.pdf">http://biochar.illinois.edu/Peterson.pdf</a></font></p>
<p><font face="Tahoma">In this Powerpoint presentation, he shows that TLUD biochar had a lower surface area than biochar made by pyrolysis.</font></p>
<p><font face="Tahoma">I think there are some questions to answer:</font></p>
<p><font face="Tahoma">1) Is it commonly the case the a short period of char-burning will raise the temperature of the bed of char sufficiently to drive off all condensed volatiles?</font></p>
<p><font face="Tahoma">2) Is there any difference between forced and natural draft TLUDs?</font></p>
<p><font face="Tahoma">3) How recalcitrant to decomposition is tar in soil, and in particular, tar embedded on biochar? Is the occlusion of pore space long-term?</font></p>
<p><font face="Tahoma">And a final comment. Users of TLUDs will have to learn how to drive them properly if they want to make good quality biochar.</font></p>
<p><font face="Tahoma">Thanks, Rajan, for your observations.</font></p>
<p><font face="Tahoma">Cheers,</font></p>
<p><font face="Tahoma">Julien.</font></p>
<br clear="all">
<br>
-- <br>
</div>
<div dir="ltr">Julien Winter<br>
Cobourg, ON, CANADA<br>
</div>
</div>
</div>
</body>
</html>