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<DIV><FONT face=Arial>Dear Dale</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>You raise excellent points about the desirability of
finding an "Alternative to Charcoal". I feel that the problem is both very
complex, AND very simple at the same time. The problem is very complex, when
dealt with, as a whole, but very simple when broken down into the various facets
of the issue that complicate it.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>If we look at the "continuum" between wood as a fuel, and
charcoal as a fuel, we see that at the "Wood End" and the "Charcoal End", there
is a clear preference, need, or requirement for the respective fuels. In the
center, there is a "gray area", where either fuel can be utilized, to greater or
lesser advantage and disadvantage.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>The problem is somewhat further complicated by those who
see charcoal as a "climate change tool" and superimpose climate change
considerations on stoves, perhaps even to the degree of relegating the
fundamental heating and cooking aspects of a stove to a secondary level of
importance. </FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Everything starts with the biomass fuel... wood, grasses,
agricultural products or waste, etc. In the logic I am about to lay out, I state
that there are fundamentally three kinds of stove:</FONT></DIV>
<DIV><FONT face=Arial>1: A "Full Combustion Biomass stove", where all fuel
is intended to be burned to completion</FONT></DIV>
<DIV><FONT face=Arial>2: A "Partial Combustion Biomass Stove", where char or
charcoal is a desired end product. (This charcoal can be subsequently used as
fuel, or as biochar.)</FONT></DIV>
<DIV><FONT face=Arial>3: A "Charcoal Combustion Stove."</FONT> </DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>In the interests of simplicity, I ignore "Charcoal
Retorts", because of their basic thermal inefficiency.... much of the pyrolysis
gas energy is simply vented. However, a retort that made use of the pyrolysis
gas heat could be termed a "Partial Combustion Biomass Stove.'</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>A major advantage of this approach would be that it would
clearly categorize stoves, and as a consequence, would allow for three different
testing protocols.Each Testing protocol could be set up to best capture the
performance parameters that were of most importance to each stove
system.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Crispin's Proposed Stove testing Protocols are perhaps
best for "Full Combustion Biomass Stoves." Equivalently relevant protocols could
be developed for "Partial Combustion" and "Charcoal stoves.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>I feel that the process should be "Customer Driven." If a
Customer wants to burn charcoal as fuel, then that is his decision. Or, if he
wants to produce charcoal, for resale, or for use as biochar, or for subsequent
use as a fuel, then that also should be his decision. This is where a good set
of Testing Protocols would be really helpful... they would allow the Customer to
select the stove system (or systems) that best met his needs.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Note also that when fundamental "performance information"
was available from the above three protocols, it would be very easy to develop a
spread sheet that factored in all the relevant information, so that the Customer
could make a rational decision on what would be the best stove system for his
particular circumstances.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Best wishes,</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Kevin</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>. </FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=dandreatta@sealimited.com
href="mailto:dandreatta@sealimited.com">Andreatta, Dale A.</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=stoves@lists.bioenergylists.org
href="mailto:stoves@lists.bioenergylists.org">Discussion of biomass cooking
stoves</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, April 08, 2013 6:09
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Stoves] Alternative to
charcoal</DIV>
<DIV><BR></DIV>
<DIV class=WordSection1>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">At
the recent ETHOS conference Paul Means and Chris Lanning gave a very
thought-provoking talk about an alternative to charcoal. The basic idea
was to use a gasifying stove with prepared wood fuel. The prepared wood
fuel would be bought by the user instead of charcoal, and the supply chain
would be similar to charcoal. The big advantage is that the very
inefficient step of charcoal production is eliminated. The stove would
hopefully be easy to use and would smoke very little, so as to retain the
benefits of a charcoal stove. <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">Their
proposed fuel was crumbled wood, which would work well, but seemed to me to
require a lot of big machinery and capital. How could one go from a tree
to a fuel that would burn well in a gasifier with as little work as possible,
and without too much costly equipment? The fuel should be as low
or lower in cost than charcoal per unit of food cooked, and give a better
ratio of food cooked per unit of tree. <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">I
did some preliminary experiments. With 779 g of natural wood from the
trees in my yard, I used a Paul Anderson Champion gasifier and boiled 5 liters
in 21.4 minutes (corrected). After an easy light the stove burned
steadily with no attention, other than turning down the primary air when
boiling started. About 10 minutes after boiling the pyrolysis ended and
I transferred 123 grams of char sticks, glowing only weakly, into a charcoal
stove, and continued simmering until nearly 2 hours after the start of
boiling. I had good turndown on the charcoal stove and a lid on the
pot. There was a little smoke during the pyrolysis phase, but not too
much. This seems like excellent stove performance.
<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">Had
I used a very good charcoal stove to perform a similar task, it might have
taken 240 g of charcoal. This would take about 1800 g of wood if the
charcoal were made efficiently, or 3000 g if it were made normally.
(Reference Means and Lanning on the efficiency of charcoal
production.)<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">The
wood I started with was about 1 inch diameter (2.5 cm) by 6 inches (15 cm)
long, cut from my trees and dried outdoors but under cover for some
months. I didn’t measure the moisture content, but a previous
oven-drying test with similar wood showed about 12-14% moisture. A
previous test with larger diameter wood didn’t go well, so I think this is
about the maximum possible diameter. I don’t know how long it took to
get to this moisture content, not months I’m sure, but at least some number of
days. <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">The
production method for this alternative to charcoal would be to use a chain saw
to cut wood into convenient lengths while in the forest, then take it to a
central place. Here, use electric saws and/or hydraulic splitters
to cut the wood to the appropriate size. Give the wood a modest amount
of drying in the sun, or in some simple oven. The wood might have to
finish drying at the place of use. I expect that split wood would dry
faster than cut sticks, since the moisture doesn’t have to pass through the
bark. Alternatively, use a chain saw and engine powered splitter to cut
the wood to size in the forest, then transport to a central place for
drying. When fairly dry, transport the wood to the users as with
charcoal. During transport, the energy per unit weight would be lower
than charcoal, but the energy per unit volume would be similar. The user
might be given the option of buying shorter sticks for cooking smaller meals,
or longer sticks for larger meals. <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">In
comparing the economics of this method to charcoal, I would think of the cost
of the fuel as coming from 5 elements; the cost of the trees, the cost of the
processing equipment, the cost of the labor, the cost of the transportation
and distribution, and the cost of the stove. If the trees are free, then
the fact that you don’t cut as many trees doesn’t help much. If the
trees must be paid for, then this method looks more attractive. The
processing equipment for charcoal is virtually free, but hopefully this method
doesn’t take too much equipment. The labor for this method might be
similar to charcoal, but it might be less because you are cutting and
processing a lot fewer trees to serve the same number of customers.
Transportation would be more expensive, since you are shipping more mass,
though not a lot more volume. This method would require a gasifier or
T-Char stove, which would be an expense, though hopefully not a lot compared
to the annual cost of fuel. <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">Thus,
if the trees must be paid for, this method might be attractive to the consumer
of the fuel, the producer of the fuel, and to the forest. If the trees
are not paid for, this method looks less attractive, though the forest would
still benefit and some outside subsidy might be
available.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: black; FONT-SIZE: 11pt">Dale
Andreatta, Ph.D., P.E. <o:p></o:p></SPAN></P></DIV>
<P>
<HR>
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