<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Arial; font-size: 12pt; color: #000000'><style>p { margin: 0; }</style><div style="font-family: Arial; font-size: 12pt; color: #000000"><style>p { margin: 0; }</style><div style="font-family: Arial; font-size: 12pt; color: #000000"><style>p { margin: 0; }</style><div style="font-family: Arial; font-size: 12pt; color: #000000">Alex cc stoves list:<br><br> 1. Thanks for the input. I also have found a case where CO2 exceeded CO content: see Fig 3 in<br>http://ncsu.edu/bioresources/BioRes_04/BioRes_04_3_0946_Wang_CDYZS_Gas_Char_Microwave_Pyrol_Pine_Sawdust_504.pdf<br> <br> 2. But in general I have found CO to be (by far) the largest pyrolysis gas output. See for instance, Fig 4 at:<br> http://www.btgworld.com/uploads/documents/Gasification%20Attachment%20Website%20v2.pdf<br><br> The use of equivalence ratio (used in that figure) could be a very good one for us to try to report.<br><br> 3. I haven't found the right cite yet - but some might like this paper/chapter showing a range of values for CO:<br>http://nariphaltan.virtualave.net/gasbook.pdf<br><br> 4. I wandered around various gas monitoring equipment web sites - and saw lots on IR approaches. Do you think that is the right one? I have given up looking for an optimum approach - as there is a huge array out there - and mostly very expensive. If I had to buy an instrument, I would start by seeing what University researchers report what they are using. Maybe someone on the list is into this measurement topic.<br><br>Ron<br><hr id="zwchr"><b>From: </b>"Alex English" <english@kingston.net><br><b>To: </b>"Discussion of biomass cooking stoves" <stoves@lists.bioenergylists.org><br><b>Sent: </b>Tuesday, October 25, 2011 4:54:41 AM<br><b>Subject: </b>Re: [Stoves] Hi TLUDers -- and EPA testing questions<br><br>
Ron, Crispin,<br>
Many moons ago, when I had access to an IR CO,CO2 monitor, I
filtered the gasses before the flame on a TLUD. If memory serves me
I got 9% CO and 15% CO2. But memory sometimes seems to be serving
others. If only we had access to the old archives, I reported it to
this list at the time, but alas the 'server' changed. It amazes me
that nobody has done this since.<br>
Alex<br>
<br>
<br>
On 24/10/2011 10:41 PM, Crispin Pemberton-Pigott wrote:
<blockquote cite="mid:096d01cc92bf$9f3f5b00$ddbe1100$@gmail.com">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Dear
Ron</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
<div>
<div>
<div>
<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">>></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">“For
those not having experience with TLUDs, Dean's
reference to "no primary air can make it up", means
that the oxygen is "entirely" used to produce carbon
monoxide.”</span><span style="color:black"></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">…</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">>></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">It
is really rare to find a normalised CO emissions
factor (not concentration in the emerging gases) above
100,000 ppm. I have only see it once and I work with
some of the wildest devices the imagination has
produced. </span><span style="color:black"></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">
<b>[RWL: This part I don't understand. Neither Dean
or I were talking about anything other than primary
air. </b></span><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
see that you did not follow. I am sure is it my
method of describing it. Here is a short version:
You can’t get pure CO from biomass pyrolysis for
inherent chemical reasons. </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Proof
that I offer: I have measured CO production across
a wide range of conditions and it is almost
impossible to get more than 10% CO even when it is
theoretically possible (from the elemental
composition) to get 40%.</span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><span style="color:#1F497D">>></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">CO(ppm)
* (EA+100%) = CO(EF) at O2=0% (the O2 is factored
out). </span><span style="color:black"></span></p>
<p class="MsoNormal"><span style="color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">
<b>[RWL3: The subject of excess air for testing the
completeness of combustion (after adding secondary
air and releasing the majority of the energy) is
extraneous to the sentence under discussion.]</b></span><span style="color:black"></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">That
is how to work out what the CO level is, in ppm.
100,000 ppm is 10%.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">>></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
mention this to support my conclusion that the O2
tends to create ‘fuel moisture’ very easily.</span><span style="color:black"></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span></b><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
have personally measured the gases coming up through
the fuel bed in a TLUD (a borrowed high quality
tool) and the dominant gas was CO (many millions of
ppm). </span></b><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">That
is impossible. 1 million parts per million is 100% CO.</span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">>></span></b><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">
RWL4: My main concern is with Crispin's above
next-to-last sentence: "</span></b><i><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
am expressing doubts that level could be created in
a TLUD that was not first run as a regular fire.</span></i><span style="color:black"></span></p>
<p class="MsoNormal"><b><span style="color:black"> The
word "TLUD" should say to all that the test
operation was NOT run as a regular fire. They are
as near to polar opposites as the stove world can
get. So this is to ask Crispin what he is saying
here and what part of my response he is objecting
to?</span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
am offering a method of how to get a CO content as
high as 10%. Start a regular fire, get it going well,
then enclose it in a vessel while hot and running.
This can produce 10% CO, but a TLUD cannot. That is my
contention.</span></p>
<p class="MsoNormal"><span style="color:black"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Biomass
needs just a little more air (Oxygen) to completely
use up the H2 and then breathe in whatever additional
air would burn all the Carbon. In any real file, some
of the C becomes CO and CO2 (surface reactions
mentioned by Dr Tom Reed in a previous discussion).</span><span style="color:black"></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">>></span><span style="color:black"> <b>[RWL: I hope we can get a
specific citation for/from Tom here. </b></span><b><span style="color:#1F497D"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">He
addressed it directly previously on two occasions. </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="color:#1F497D">></span><span style="color:black">At the hot surface from which
(very complicated and numerous [1000's of
species??]) pyrolysis gases are emerging, my
understanding of the pyrolysis surface effect
literature is that "all" (given control of the
incoming oxygen flow) are turned into CO and water.
</span><span style="color:#1F497D"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">My
point is that if there is NO air entering, virtually
all the O2 in the fuel is turned into water. The
great proportion. Some of the H2 is left in the gas
but is it hard to find an H2(EF) of 15,000 (1.5%). I
have no problem with others contradicting this with
real measurements.</span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="color:#1F497D">>></span><span style="color:black">The relatively small amount of
CO2 that is produced near the surface (not ON) is
converted back to CO as it interacts with the hot
char above it</span><span style="color:#1F497D"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">This
only happens under certain conditions and not when
it is cool. Dr Tom was mentioning C=> CO2
reactions taking place above 400 C on the surface.
CO can also be formed, and volatiles (which contain
carbon) can break down into CO as well. The CO in
the gas is not necessarily produced from CO2 and is
unlikely if the temperature is low because it has to
absorb a lot of heat to do so (24 MJ/kg).</span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></b></p>
<p class="MsoNormal"><b><span style="color:#1F497D">></span><span style="color:black"> So I repeat - I am mystified by
this message and about what is at dispute. </span><span style="color:#1F497D"></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I
am not sure there is a dispute. Perhaps the
clarification will suffice.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Regards</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Crispin</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></p>
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