Dear Doug, Rolf and all:<br><br>We need to be more specific when talking about various charcoal processes.<br><br>Kiln charcoal making is said to produce approximately 1/3 gas, 1/3 tar and 1/3 charcoal! I believe that the true charcoal yield can't exceed the lignin content of the wood which is typically around 20%, so the above numbers are for a charcoal that has reabsorbed more of the tars/volatiles. <br>
<br>TLUD charcoal making in my stove typically produces 15-20% charcoal, in line with the lignin content. I recently burned Mesquite chips and got a yield of 35%! Mesquite is said to have 64% lignin! This would seem to confirm it. <br>
<br>Lignin is a hydrocarbon and not digested by organisms other than termites. You find large logs of pure lignin in many forests. This lignin breaks across the grain because the cellulose carbohydrate has all been removed. <br>
<br>Incidentally, lignin evolved 400 M years ago when life emerged from the ocean and began to occupy Gonwandaland. Lignin is necessary for vascular plants that carry water up hundreds of feet. At that time, Earth had an atmosphere of > 20% CO2 and trees grew faster than they could be biodegraded. The result was buried wood which then became buried and formed our coal deposits. <br>
<br>You can easily calculate from the pressure of the atmosphere and the diameter of the earth that our atmosphere weights 5.5E15 tons, and so contains 1.1E15 tons of O2, generated by photosynthesis. Normally the O2 is consumed when plants die, but there must be ~ 4E15 tonnes of sequestered carbon, mostly coal to permit us the luxury of 21% O2 in our atmosphere. <br>
<br>Let's not upset the balance too much or too fast. <br><br>TOM REED BEF<br><div class="gmail_quote">On Fri, Apr 15, 2011 at 6:21 PM, doug.williams <span dir="ltr"><<a href="mailto:Doug.Williams@orcon.net.nz">Doug.Williams@orcon.net.nz</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div>
<div><font face="Arial"><font size="2"></font><font size="2"></font><br><font size="2"></font></font></div>
<div><font size="2" face="Arial"><b>Hi Rolf,</b></font></div>
<div><b><font size="2" face="Arial"></font></b> </div>
<div><b><font size="2" face="Arial">In answer to these
two questions:</font></b></div>
<div><b><font size="2" face="Arial"></font></b> </div>
<div><font size="2" face="Arial">I have also thought about the cold char
acting as a filter for the tars in <br>the distillation fumes so as to enrich
the biochar with these, but so far I <br>have never found any comments on
this.</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial"><b>Charcoal makes a good filter for
particulates, but if the pyrolisis gas from a charcoal kiln is anything less
than say 475C, the tars will just condense and quickly block the filter bed. You
will also find the gas ducts will block if the temperatures
drop.</b></font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">The filtered gases would go through an engine to be
completely burnt.</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial"><b>Unfortunately, this would be very unlikely
to succeed, as pyrolisis gas would need to be wet scrubbed to grab all the
condensable tars. The toxic black liquor is then a environmental disposal
issue.</b></font></div>
<div> </div>
<div>What do you use as a binder?</div>
<div> </div>
<div><b>Depending on the type densification, you can use the tar if
collected from a condenser, or more user friendly starch powders from a variety
of crops.<br></b><br></div>
<div><b>Hope this will help to keep your hands clean (:-)</b></div>
<div><b></b> </div>
<div><b>Doug Williams,</b></div>
<div><b>Fluidyne.</b></div>
<div><br><br> </div></div>
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