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<DIV><FONT face=Arial>Dear Ron</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px"
dir=ltr>
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=rongretlarson@comcast.net
href="mailto:rongretlarson@comcast.net">rongretlarson@comcast.net</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> ; <A title=biochar-policy@yahoogroups.com
href="mailto:biochar-policy@yahoogroups.com">biochar-policy</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A title=english@kingston.net
href="mailto:english@kingston.net">Alex English</A> ; <A
title=kchisholm@ca.inter.net href="mailto:kchisholm@ca.inter.net">Kevin
Chisholm</A> ; <A title=tmiles@trmiles.com
href="mailto:tmiles@trmiles.com">Tom Miles</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, December 11, 2012 2:09
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Stoves] Equipment required
for testing stoves</DIV>
<DIV><BR></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt">Lists (adding
biochar-policy also), Kevin, Alex, Tom (who I add, because he
speaks Portuguese and might have caught an answer when we were in Manaus a few
years ago)<BR><BR> See below<BR>
<HR id=zwchr>
<B>From: </B>"Kevin" <<A
href="mailto:kchisholm@ca.inter.net">kchisholm@ca.inter.net</A>><BR><B>To:
</B>"Discussion of biomass cooking stoves" <<A
href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</A>>,
"Alex English" <<A
href="mailto:english@kingston.net">english@kingston.net</A>><BR><B>Cc:
</B>"Discussion of biomass cooking stoves" <<A
href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</A>><BR><B>Sent:
</B>Monday, December 10, 2012 8:24:34 PM<BR><B>Subject: </B>Re: [Stoves]
Equipment required for testing stoves<BR><BR>
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<DIV><FONT face=Arial>Dear Ron</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Would you agree that the Amazonians made Terra Preta
with low temperature char? <BR> <B>[RWL1: I
think others may have an answer - maybe based on spectroscopy. I will
start looking but don't know that field well enough to know what others may
have concluded about these ancient soils. I fear that 500 years
(minimum) in soil may hide the initial character that we can readily see in a
University setting. I know from being in several Amazonian biochar
"pits" that it is pretty hard to find a piece big enough to test. I
think it entirely possible that char left over from simple three-stone fires
could have been made at 500-600 C (or higher). Would you call those
temperatures high or low?] </B></FONT></DIV>
<DIV><FONT face=Arial><B></B></FONT> </DIV>
<DIV><FONT face=Arial><B># KC1: Obviously, I am speculating, but I would
speculate that Terra Preta was made with charcoal from a number of
sources:</B></FONT></DIV>
<DIV><STRONG>1: Char residue remaining after charring or burning of
"wood waste from initial jungle clearing.</STRONG></DIV>
<DIV><STRONG>2: Char residue remaining from charring or burning of
agricultural waste and weeds</STRONG></DIV>
<DIV><STRONG>3: Char and ash residue from cooking fires and possibly smudge
pots</STRONG></DIV>
<DIV><STRONG>4: Organic fertilizer supplements, from humanure, composted food
scraps, and probably dredgings from oxbow lakes.</STRONG></DIV>
<DIV><STRONG>I would consider 500-600 C to be a "low temperature char." I
haven't seen any references to the existence of bellows technology in ancient
Amazonia, that would be necessary to produce significantly higher
temperatures.</STRONG></DIV>
<DIV><STRONG>It is likely that the Amazonian Terrapretians would have quickly
noticed if such low temperature char additions to their agricultural practises
were causing poor results. If that was the case, they likely would have taken
steps to avoid application of char to fields. They would be looking for short
term benefits or harm. Given that they used char on a widespread basis, and
that it was basically low temperature char, it would thus seem that Terra
Preta worked with low temperature char, and it worked relatively quickly, not
requiring an aging period of several years.</STRONG></DIV><FONT
face=Arial><STRONG></STRONG></FONT></DIV><FONT face=Arial></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px"
dir=ltr><FONT face=Arial>
<DIV
style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><BR><BR><BR>If
so, are there any test results to show that an "intermediate
temperature char" would give better results than the "low temperature
char?"<BR> <B>[RWL2: I think that people
like Dr. Johannes Lehmann and Evelyn Krull may be getting to an answer for
some specific soil and species. I keep looking for
it.<BR> My note below to Alex was to make it easier
for users to know what is being used Some of my favorite biochar
scientists like Drs. Julie Major and Christoph Steiner were forced to use char
bought off the side of a remote Amazonian road. <BR>
I haven't seen any data emphasizing tests with a range of
temperatures. Drs. Stephen Joseph (low) and Hugh McLaughlin (high)
recommend different temperature regimes.] </B></DIV>
<DIV
style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><B></B> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><B>#KC2: Is
it perhaps likely that "basic low temperature biochar" is good for general
agricultural applications, but that intermediate and high temperature chars
may be better for addressing special agricultural
problems. </B><BR></DIV></FONT>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial>I seem to recall that "high temperature char" and/or "activated
char" gives inferior results in a biochar application.
<BR> <B>[RWL3: How about giving a cite for
that?] </B></FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B></B></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B>#KC3: Unfortunately, I cannot point to a specific
cite.</B><BR><BR>Does this impression make sense to you?
<BR> <B>[RWL4: No - certainly not as a universal
truth/] </B></FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B></B></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B>#KC4: Universal truths are scarce and hard to find. :-) If you
put yourself in the circumstances of an Amazonian Terrapretian of 3,000 years
ago, what would you do differently?</B></FONT><FONT face=Arial><BR><BR>If so,
is there a "preferred char making temperature range"?
<BR> <B>[RWL5: I am sure that it depends a lot on the
intended recipient soil - and probably on the plant species. #KC5:1
Certainly! Jungle woods can vary in density from balsa at about 10 lb/cubic
foot, to Lignum Vitae, at about 68 pounds per cubic foot.</B></FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B></B></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B>My focus in this exchange below with Alex is to give soil
researchers and stove users a better idea of even getting close to knowing
what char-T they are using. </B></FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B>#KC5:2 Char making temperature is easy to determine. It should
thus be very easy to determine the importance, or lack thereof, of char making
temperature. It would be very good to know this, to reduce variables in a test
analysis.</B></FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B></B></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B> There is a good bit of information out there relating pH
to production temperature - but pH also depends on fuel size and ash content
and pH changes over time. Who knows what else leads to a
"preference"? <BR> And we also hear from Dr.
Spokas that what happens after char production is maybe as much or more
important. I think it is absolutely amazing that we hear so many
good reports (and few bad reports) when we know so little even about the
char-production temperature - and even the wood species, etc, etc,
etc. Ron] </B></FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B></B></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial><B>#KC: With that many "good reports" and so few "bad reports", and
with so many char variables, this would tend to downplay the importance of
char variables. The "bad reports", presuming that they were competently done,
could provide very important insights into what works, and what
doesn't.</B></FONT></DIV><FONT face=Arial><STRONG></STRONG></FONT></BLOCKQUOTE>
<BLOCKQUOTE
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<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
size=4>Best wishes,</FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
size=4></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
size=4>Kevin<BR></FONT></DIV></BLOCKQUOTE>
<BLOCKQUOTE
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dir=ltr></FONT>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial>Best wishes,</FONT></DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial></FONT> </DIV>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><FONT
face=Arial>Kevin</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; FONT-FAMILY: Arial; COLOR: #000000; MARGIN-LEFT: 5px; FONT-SIZE: 12pt; 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=rongretlarson@comcast.net href="mailto:rongretlarson@comcast.net"
target=_blank>rongretlarson@comcast.net</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=english@kingston.net
href="mailto:english@kingston.net" target=_blank>Alex English</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A
title=stoves@lists.bioenergylists.org
href="mailto:stoves@lists.bioenergylists.org" target=_blank>Discussion of
biomass cooking stoves</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, December 10, 2012 9:46
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Stoves] Equipment
required for testing stoves</DIV>
<DIV><BR></DIV>
<DIV
style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt">Alex:<BR><BR>
Thanks:<BR><BR> I see only a few remaining questions related to the
thermocouples. My interest is only in being able to report to the soil
scientists the temperature at which the char was
produced.<BR><BR> Q1. I think we should be able to
say that a time average of a central thermocouple measurement showing a
slight drop over time of the highest numbers is a pretty good estimate -
that could be reproduced for "any" similar "flaming pyrolysis"
approacd. The properties (pH, surface areas, labile component, etc) of
such char should be compared (a Master's thesis?) with char produced
via other means. I think Nat Mulcahy's non-flaming pyrolysis approach
can produce varying temperature char. An all-electric heating approach
in any oxygen-free environment , operated at different temperature should
also be used to compare the char properties with those from stoves.
Maybe that data is already out there?? <BR><BR> Q2.
I think there could be some influence of the initial fuel moisture
content. Do you (anyone) have an opinion on that? I am
trying to avoid having to always measure temperatures, but still be able to
give an indication of the "likely" char temperature, by knowing how long a
specific volume or weight of fuel lasted.<BR><BR>
Q3. I wonder if the char temperature as measured by a
thermocouple system like yours would also be a function of the fuel
itself (species, characteristic size, shape, etc.)<BR><BR>
Q4. I am pretty sure that the top and bottom char will be
significantly different in a typical cooking cycle, where a very high flame
temperature is desired at first (affecting only the top part of the fuel
load), and then a much lower temperature desired later (affecting only the
lowest portion of the fuel load). My question, for anyone, is
whether an average temperature is at all valuable, if the average (obtained
from the total duration of the pyrolysis) covered a wide range of production
temperatures. Actually I have heard so many different opinions on the
best production temperature - maybe a mixture of char temperatures might be
an advantage. Thoughts?<BR><BR><BR>Ron<BR><BR><BR>
<HR id=zwchr>
<B>From: </B>"Alex English" <english@kingston.net><BR><B>To:
</B>rongretlarson@comcast.net, "Discussion of biomass cooking stoves"
<stoves@lists.bioenergylists.org><BR><B>Sent: </B>Monday, December 10,
2012 4:38:56 AM<BR><B>Subject: </B>Re: [Stoves] Equipment required for
testing stoves<BR><BR>
<DIV class=moz-cite-prefix>Ron,<BR><BR>On 09/12/2012 8:33 PM, <A
class=moz-txt-link-abbreviated href="mailto:rongretlarson@comcast.net"
target=_blank>rongretlarson@comcast.net</A> wrote:<BR></DIV>
<BLOCKQUOTE
cite=mid:491634252.590547.1355103219464.JavaMail.root@sz0133a.emeryville.ca.mail.comcast.net>
<STYLE>p { margin: 0; }</STYLE>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt">Alex
etal<BR><BR> Thanks for the cite. I think I understand most of
the plot - which was of amazing duration!. I am especially
amazed at how uniform (and high) the flame temperature was in the late
time plot, even as the other plots were
dropping.<BR><BR></DIV></BLOCKQUOTE>It is a very steady gas producer.
Conditions are constant except for the distance and path composition between
the pyrolysis front and the burner. If it can be done over 100cm then why
not 200 or 300.<BR>
<BLOCKQUOTE
cite=mid:491634252.590547.1355103219464.JavaMail.root@sz0133a.emeryville.ca.mail.comcast.net>
<DIV
style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt">
a. Since you have this one from 2000, you probably have quite
a few more - from which I/we might extract a good bit more
information/ Any other similar plots around that you can
post?<BR></DIV></BLOCKQUOTE>No I don't.<BR>
<BLOCKQUOTE
cite=mid:491634252.590547.1355103219464.JavaMail.root@sz0133a.emeryville.ca.mail.comcast.net>
<DIV
style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><BR>
b. I am surprised that the "pyrolysis gas temperature" was so
much lower than the temperature of the char. Where was the probe for this
measurement - and had there been some mixing of secondary air at this
point?<BR></DIV></BLOCKQUOTE>No mixing of secondary air at that point. That
occurs in and above in a 5cm burner mixing pipe. The tmperature
difference is largely due to the nature of unshielded thermocouples in
gas.For the most part thermocouples radiate away heat according to the
temperatures of the surfaces that make up the sphere around them. A
thermocouple buried in the pellets that are all carbonizing at 700C will
give a fairly accurate measurement. A thermocouple in the gas above the top
of the pellet bed will radiate to the pellet bed and, in this case the
uninsulated container walls. The more that pellet bed shrinks the larger the
portion of the radiant sphere that is the cool container walls. The larger
the thermocouple, the greater the radiant cooling , the lower the
measurement. The higher the temperature the greater the radiant loss, to the
forth power. All the gas is also radiating and convecting heat to the
container walls. So there are two reasons for a slow drop in gas
temperature, and one reason for not trusting either. The same holds true for
the absolute value of post combustion measurement. <BR><BR>There are
<SPAN
style="TEXT-ALIGN: left; WIDOWS: 2; TEXT-TRANSFORM: none; BACKGROUND-COLOR: rgb(255,255,255); TEXT-INDENT: 0px; DISPLAY: inline !important; FONT: small/16px arial,
sans-serif; WHITE-SPACE: normal; ORPHANS: 2; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(34,34,34); WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">gas-</SPAN><EM
style="TEXT-ALIGN: left; LINE-HEIGHT: 16px; WIDOWS: 2; TEXT-TRANSFORM: none; BACKGROUND-COLOR: rgb(255,255,255); FONT-VARIANT: normal; FONT-STYLE: normal; TEXT-INDENT: 0px; FONT-FAMILY: arial,sans-serif; WHITE-SPACE: normal; ORPHANS: 2; LETTER-SPACING: normal; COLOR: rgb(0,0,0); FONT-SIZE: small; WORD-SPACING: 0px">aspirated
pyrometers which shield a thermocouple with ceramic layers that approach gas
temperatures and give better numbers. We will soon be using an 10 footer to
probe the chain grate stoker gasses in carbonizer- pyrolysis-gasifier
mode.<BR><BR>Grate fun.<BR></EM>
<BLOCKQUOTE
cite=mid:491634252.590547.1355103219464.JavaMail.root@sz0133a.emeryville.ca.mail.comcast.net>
<DIV
style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><BR>
c. What is the present disposition of this
equipment?<BR></DIV></BLOCKQUOTE>Its in the recoverable bone yard. I should
have shown it to Crispin when he was here.....or perhaps not:)
<BR><BR>Alex<BR>
<BLOCKQUOTE
cite=mid:491634252.590547.1355103219464.JavaMail.root@sz0133a.emeryville.ca.mail.comcast.net>
<DIV style="FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 12pt"><BR>Nice
work<BR><BR>Ron<BR><BR><BR></DIV></BLOCKQUOTE><BR></DIV>
<P></P>
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