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Hi Tami,<br>
<br>
Thanks for the detailed response.<br>
<br>
The answer to your question is "the more we can have the better".
Realistically, it would be too easy to end up with too much
information and just become overwhelmed. Even if it were possible to
obtain full speciation measurements of the pyrolysis/gasification
products, it probably isn't practicable to use. For example, in the
case of gaseous turbulent combustion there is already too much of a
compromise needed for methane combustion: detailed kinetic
mechanisms are often too large for CFD...obviously the problem
becomes much worse for other fuels. There is a huge amount of work
in the area of kinetic mechanism reductions (mainly for engine
fuels), but detailed kinetics of tars seems out of the question any
time soon. <br>
<br>
In the first instance, it would be interesting to see a plot of the
mass spectrum of the pyrolysis/gasification products in a TLUD
(before the secondary air inlets) for different operating
conditions. It would also be nice to know the global C/H ratio. We
are in the process of getting a new GC/MS, but only to 300 amu.
We'll wait and see how that goes. The long-term plan is to include
this in a model of the system, as well as subsequent experiments of
the specific details of soot production in the combustion zone.
However, this is all work to be done in the future.<br>
<br>
Cheers,<br>
Paul<br>
<br>
<br>
<div class="moz-cite-prefix">On 13/11/2016 6:52 AM, Bond, Tami C
wrote:<br>
</div>
<blockquote
cite="mid:B265653D-CC47-4D01-9CB6-5A77BDA3A14F@illinois.edu"
type="cite">
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Hi Paul, and all,
<div class=""><br class="">
</div>
<div class="">Sorry that I have not been keeping up with Stoves
discussions….</div>
<div class=""><br class="">
</div>
<div class="">We have fussed a bit with trying to characterize the
organic matter emitted from wood combustion. </div>
<div class=""><br class="">
</div>
<div class="">What kind of characterization do you want? Full
speciation is well-nigh impossible. But one needs to start with
the question of what you want to know and why? </div>
<div class="">The problem is that this stuff is complex chemically
and doesn’t take well to matching with standards. </div>
<div class=""><br class="">
</div>
<div class="">
<div class="">Brief summary of what I know:</div>
</div>
<div class="">- GC/MS is really hard for characterization because
it is poor at identifying compounds that are large (molecular
weight) and polar. Wood organics are both. You’ll get the light
organic material, but that’s a very small fraction of the
emissions. You can get into derivatization of the emissions
before GC/MS and that may get you a little more. See all Jamie
Schauer’s, Wolfgang Rogge’s work. Most of it ends up being
classified as “UCM” (unresolved complex mixture). </div>
<div class="">- FTIR— have tried a little. Although it nominally
gives you functional groups, and occasionally you can see
differences between one kind of wood or burning condition and
another, it’s not very quantitative. Plus there are a lot of
overlaps between the interesting functional groups, so you can’t
distinguish some of them.</div>
<div class="">- 1NMR— kind of like FTIR— you can sort of see
functional groups and that’s about it. </div>
<div class="">- UV-Vis— used for humic matter (and some “tar”
isn’t far off that)— Again not quantitative, rather just gives a
sense of how strong an absorber it is. You won’t see any
structure as you do in UV-Vis of individual compounds. There are
so many compounds that the entire spectrum smooths out. </div>
<div class=""> —> From our UV-Vis work we found that most of
the stuff dissolves in methanol, not hexane not water. (Chen
& Bond, Atmos Chem Physics 2010, open access)</div>
<div class="">- 13CNMR— which can get at the carbon skeleton
rather than functional groups… tough. You need HUGE sample sizes
and they don’t stay suspended because anything concentrated
enough to measure wants to precipitate. We ended up using DCM, I
think— I’d have to check. And then, the result was not all that
interesting: we again couldn’t distinguish the unsaturated
bonds, e.g. aromatic vs conjugated but linear bonds. </div>
<div class="">
<div class="">- LC/MS— expensive and full of artifacts— I’ve
never gotten into it. Too expensive and haven’t seen the
benefit, although I’d be interested if someone tried.</div>
</div>
<div class=""><br class="">
</div>
<div class="">The question, again, is what you want to know and
why. If it’s some kind of physical property of the emissions,
you’d be better off measuring that.</div>
<div class=""><br class="">
</div>
<div class="">Tami</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
<div class="">
<blockquote type="cite" class="">
<div class="">On Sep 2, 2016, at 12:22 PM, Paul Medwell <<a
moz-do-not-send="true"
href="mailto:paul.medwell@adelaide.edu.au" class=""><a class="moz-txt-link-abbreviated" href="mailto:paul.medwell@adelaide.edu.au">paul.medwell@adelaide.edu.au</a></a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class=""><span style="font-family: Helvetica;
font-size: 12px; font-style: normal; font-variant:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: auto; text-align: start;
text-indent: 0px; text-transform: none; white-space:
normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color:
rgb(255, 255, 255); float: none; display: inline
!important;" class="">Dear Philip,</span><br
style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<br style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<span style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255); float: none;
display: inline !important;" class="">Thanks for another
great suggestion.</span><br style="font-family:
Helvetica; font-size: 12px; font-style: normal;
font-variant: normal; font-weight: normal;
letter-spacing: normal; line-height: normal; orphans:
auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<br style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<span style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255); float: none;
display: inline !important;" class="">This is also
something that is planned. As part of an unrelated
project we have been looking at this: we are still in
the process of finding a solvent that has a collection
yield, that doesn't interfere with (or gives an
interference profile that we can correct for) and that
OH&S will let us have. Fortunately, for the
cookstove work there are fewer constraints than the
other project (which is limited to sampling extremely
low flowrates). We'll find a solution and share it.</span><br
style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<br style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<span style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255); float: none;
display: inline !important;" class="">Cheers,</span><br
style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<span style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255); float: none;
display: inline !important;" class="">Paul</span><br
style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
<br style="font-family: Helvetica; font-size: 12px;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);" class="">
</div>
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