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<DIV><FONT face=Arial></FONT><FONT face=Arial>Dear Dale</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>----- Original Message ----- </FONT>
<DIV><FONT face=Arial>From: "Andreatta, Dale A." <</FONT><A
href="mailto:dandreatta@sealimited.com"><FONT
face=Arial>dandreatta@sealimited.com</FONT></A><FONT
face=Arial>></FONT></DIV>
<DIV><FONT face=Arial>To: "Discussion of biomass cooking stoves" <</FONT><A
href="mailto:stoves@lists.bioenergylists.org"><FONT
face=Arial>stoves@lists.bioenergylists.org</FONT></A><FONT
face=Arial>></FONT></DIV>
<DIV><FONT face=Arial>Sent: Wednesday, June 12, 2013 12:39 PM</FONT></DIV>
<DIV><FONT face=Arial>Subject: [Stoves] Burning wet wood</FONT></DIV></DIV>
<DIV><FONT face=Arial><BR></FONT></DIV>
<DIV><FONT face=Arial>> Have we ever looked at the question of how to design
a stove to burn<BR>> wood that is higher in moisture? </FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial><STRONG># You ask the most difficult questions!!
:-)</STRONG></FONT></DIV>
<DIV><STRONG><FONT face=Arial></FONT></STRONG> </DIV>
<DIV><FONT face=Arial>It would seem that this is very<BR>> important
practical issue, and that a stove that could burn wet wood<BR>> would be very
popular. </FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial><STRONG># Yes, indeed!!</STRONG></FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial> What makes a stove burn wet wood well or
poorly?</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial><STRONG># The fundamental problem is that of "lack of
sufficient energy in the primary combustion zone to gasify the fuel." So-called
"Dutch Oven Furnaces" are specifically designed for burning "wet"
biomass fuels. What they do is use an insulated gasifying chamber, so that
as much as possible of the heat released when primary air is introduced to
gasify the fuel, and some of the heat released on secondary air
combustion, is reflected back onto the "wet fuel pile" to permit the
"Gasification Plus Combustion Reaction" to continue.</STRONG></DIV>
<DIV><BR>> The only time I remember someone saying something about this
was<BR>> Crispin, who I believe said recently that preheating the primary
air<BR>> makes it possible to burn wetter wood. </DIV>
<DIV> </DIV>
<DIV><STRONG># Preheating of combustion air is certainly practical, and a "step
in the right direction", but it is only helpful to a degree, in that the energy
that preheated air can bring to the Primary Air Zone is limited.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV> This would be easy with a batch<BR>> stove, harder with continuous
feed. </DIV>
<DIV> </DIV>
<DIV><STRONG># Certainly, if you had a "good fire going", it would be relatively
easy to add some wet wood, without it quenching the fire. However, it would be
very difficult to start with a batch of wet wood, and bring it up to "good
combustion conditions." I would suggest that the best way to deal with
consistently wet wood would be to:</STRONG></DIV>
<DIV><STRONG>1: Start the fire with a batch of dry wood, to get the system up to
temperature</STRONG></DIV>
<DIV><STRONG>2: When the stove/furnace is "up to temperature", switch over
to "wet wood"</STRONG></DIV>
<DIV><STRONG>3: Run continuously.</STRONG></DIV>
<DIV> </DIV>
<DIV>Other than that, I can think of a<BR>> couple things that might help
burn wetter wood. </DIV>
<DIV> </DIV>
<DIV><STRONG># There are a number of things that can be done, if it is necessary
that one burn wet biomass fuel, most of which complicate the burning operation
and lead to a more costly "stove/furnace" system. The simplest solution, if it
is practical, is to dry the fuel adequately beforehand, but if this is
impractical, then these other techniques can be employed.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Best wishes,</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Kevin<BR></STRONG>> <BR>> Dale Andreatta <BR>> <BR>>
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