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<DIV>Tom, Tom, Listers, </DIV>
<DIV> I would think that there would be a reduction in
tars in the higher temp chars. This might have some advantages in less surface
tension of water. The tars, on the other hand may have some beneficial use in
reducing, insects, fungus or bacteria growth in chars used for soil enhancement.
The chars created in a gasifier or less efficient system such as an open fire or
various older systems of char making would all contain more ash. The extra ash
would have benefits as a nearly balanced fertilizer in the soil. Minus only
nitrogen. </DIV>
<DIV> It surprises me that higher temp chars
would have a lower surface area. Has anybody studied the
relationship between the time it takes to cook the char and the amount of
surface area created? I would think the higher temperatures and faster
cooking would rupture the cell membranes violently and to a greater extent from
flashing steam. Would this create more or less surface area? Would
carbonized cells have a greater CEC with tiny holes in them from slow cooking or
larger more accessible ruptures from fast cooking? Would some cells not rupture
completely? or be blocked in large chunks of charcoal from acting to
absorb water and minerals? </DIV>
<DIV> Obviously, the type of biomass would
also be a great variable in the surface area equation as cells rupture
based on their design. Old gunpowder makers knew this from experience that is
why low ash, high surface area Willow and Dogwood were favored. The Dogwood for
dense, high octane powder and the Willow for light, fast burninig powder. </DIV>
<DIV> I think that nature already has figured this out in
a beautiful way- as usual. Char for soil is best created in hot but inefficient
forest fires. Char for use as a fuel for man is best created with a high yield
and lots of hydrocarbons in a closed retort system. All other uses fall on
a scale in between. The Biblical saying "Render unto God what is
God's" comes to mind. And you thought it was just about taxes! </DIV>
<DIV> I like to burn my brush in a big cut open tank in
the garden. All the ash flies out into the air and lands well distributed all
over the garden. This saves me the task of spreading the ash. In forest fires
the majority of the char forms underground or under ash. Again, Nature
is still one or many steps ahead of us. </DIV>
<DIV> Only questions, no answers as usual. No lab or even
a greenhouse anymore to experiment with. Have fun all you college types.
Let me know what you find. I do still read some of the letters now and
then.</DIV>
<DIV> Keep Charring and Stoving, </DIV>
<DIV> </DIV>
<DIV> Dan Dimiduk </DIV>
<DIV> From the peanut gallery. </DIV>
<DIV> </DIV>
<DIV>In a message dated 6/16/2013 4:41:37 PM Eastern Daylight Time,
tmiles@trmiles.com writes:</DIV>
<BLOCKQUOTE
style="BORDER-LEFT: blue 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>Stephen
Joseph should comment on the target "optimum" range set out by<BR>Lehmann and
others of 450-550 C which seems to have guided most research.<BR>According to
their work an increase in temperature to 500-700C would appear<BR>to result in
slightly lower yield and surface area. pH and CEC would be<BR>about the same.
Trials with different plants and soils since this early work<BR>may tell us a
different story. <BR><BR>We have had good results with limited use of higher
temperature pyrolysis<BR>and gasifier chars, in the 500-700C range or even
higher, when used in<BR>erosion control, filtration, vermiculture and
soil-less media. The main<BR>drawback of a gasifier char is a lower char
yield. <BR><BR>Tom Miles<BR><BR></FONT></BLOCKQUOTE></DIV>
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