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<DIV><FONT face=Arial size=2><STRONG>Hi Tom,</STRONG></FONT></DIV>
<DIV><FONT face=Arial size=2><STRONG></STRONG></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG>Pleased that you are still able to
contribute to these debates, and as you seek comment to your intentions to do
some testing, here goes(:-)</STRONG></FONT></DIV>
<DIV><FONT face=Arial size=2><STRONG></STRONG></FONT> </DIV>
<DIV><FONT face=Arial size=2>Dear Doug and all:<BR></FONT></DIV>
<DIV><FONT face=Arial size=2>The Toplit Updraft gasifier produces a different
gas (plus 20% charcoal, mostly from the lignin) than the downdraft
gasifier. I believe it may be a cleaner gas, since cellulose (~ CH2O)
vaporizes to produce a different gas (CO + H2 + ?) than the lignin. </DIV>
<DIV> </DIV>
<DIV><STRONG>My understanding of these open core concepts of gas making, is that
all the pyrolysis gases released at the descending flame front of the raw fuel,
are combusted in and with a portion of the char on the upper gas outlet
side of the flame front. Reduction would take place in this narrow band of high
temperature to give us the CO, but I would expect to see the H2 start out low,
and increase as the depth of char increases.(Needs longer dwell
time).</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Question. Have you done continuous gas analysis from start-up to
shut down?</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Your question mark in the equation suggests a combustible gas
(~CH20), which would have to survive the combustion /oxidation phase, or does
this vaporization take place as a portion of the char is
consumed first in oxidation,then reduction? Looking at these gasifying
stove rings burning as a blue gas, one might conclude that there is
little if any condensable tars present. If CH20 survives to be measured as a
gas, it's formation may be reflected in the H2 variation if present,
depending on exactly where the H2 forms. </STRONG><STRONG>Having
said that, I have no experience to draw from, to know if there is enough thermal
inertia after reduction to allow "other" reactions to take
place.<BR></STRONG><BR>As soon as we get some warm weather, I'll try to measure
the tar content from each, using my 2 kW generator and a 5 gal tar filter made
from the charcoal. <BR>Comments, suggestions?</DIV>
<DIV> </DIV>
<DIV><STRONG>As you expect to capture tars in charcoal, then I would want
to have good control over the gas cooling/filter temperatures, as the dew
points of the fuel moisture content are linked to carrying lighter
pyrolysis gas/oils through filter media.</STRONG><STRONG> I'd want to know,
especially the downdraft gasifier, if it had a proven ability to make gas
without or known condensing hydrocarbons, using the fuels of the
test.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>You also have the engine to feed you lots of info as to gas
condition, and I would use that as a pre-test before you add the charcoal
filter. A quick look under the throttle butterfly could save you a lot of
useless testing if you see the sticky stuff in there! </STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>I'm sure you know all these answers already Tom, but will watch for
your postings of the results.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Regards,</STRONG></DIV>
<DIV><STRONG>Doug Williams,</STRONG></DIV>
<DIV><STRONG>Fluidyne----</STRONG></DIV></FONT><BR><BR><FONT face=Arial
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