<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body bgcolor="white" lang="en-GB" link="blue" vlink="purple" style="background-color: rgb(255, 255, 255); line-height: initial;">
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
Philip, in short they become smaller and less sticky, correct?</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
My mental picture of a paraffin (wax in this case) is that of a long chain being chopped into smaller and smaller pieces so that, given enough time and heat input, it be reduced to gases that are easily burned. </div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
I was trying to contrast the action above a candle with the model of a particle being processed by a flame as described by Julien which is also a reasonable image. As the colour, or should I say the red and orange colours, of flames results from glowing particles.
Then there is a sort of conflict between the idea of non-glowing particles being burned away amid glowing particle<span style="font-size: initial; text-align: initial; line-height: initial;">s if the visible flames are themselves a bunch of particles. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;">Is it true that the blue portion of the flames is caused by burning CO? And that the cooler colours are from glowing particles? It seems the particles are reduced under a variety of
conditions. How do we generalise, or maybe we can't. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;">I was under the impression that Buckyballs were constructed from free carbon, not that they were reduced from something. I don't think there are any Buckyballs in paraffin wax. If
correct, it means the 'normal particles' would have to be disassembled and the carbon nanostructures assembled afterwards in an environment hot enough to pull apart the bonds but not hot enough to burn. Alternatively, in an oxygen-poor environment like the
central region of the flame tip. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;">How big are Buckyballs?</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;">Thanks</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;">Crispin </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<span style="font-size: initial; text-align: initial; line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">
<br>
</div>
<br>
<style>
<!--
p.x_MsoNormal, li.x_MsoNormal, div.x_MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif"}
span.x_MsoHyperlink
{color:blue;
text-decoration:underline}
span.x_MsoHyperlinkFollowed
{color:purple;
text-decoration:underline}
span.x_EmailStyle17
{font-family:"Calibri","sans-serif";
color:#1F497D}
.x_MsoChpDefault
{font-size:10.0pt}
div.x_WordSection1
{}
-->
</style>
<div lang="EN-ZA" link="blue" vlink="purple" style="background-color:white">
<div class="x_WordSection1">
<p class="x_MsoNormal" style="background:white"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">“</span><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">The humble candle is a good example of PM
formation. Particles exist immediately above the flame, in the clear space, but do not exist 60mm higher up, with no flame in between, meaning it is not necessary to have one to have PM burnout. This can be demonstrated using a saucer and passing it at different
heights through the gas stream.” </span></p>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">I think this is not correct. The candle soot changes its character above the flame, the particles do not disappear. Pyrolysis continues,
because temperatures are still high at that point. The products of the pyrolysis become smaller and smaller carbon particles which don’t condense readily – but they are there. That is why “buckyballs”, widely prevalent above candle flames, were missed for
so long, and why the Sistine Chapel has needed drastic cleaning every century or so (the arrival of electric lighting should spare the paintings in future). </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">Prof Philip Lloyd</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">Energy Institute, CPUT</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">SARETEC, Sachs Circle</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">Bellville</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">Tel 021 959 4323</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">Cell 083 441 5247</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D">PA Nadia 021 959 4330</span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<p class="x_MsoNormal"><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
<div>
<div style="border:none; border-top:solid #B5C4DF 1.0pt; padding:3.0pt 0cm 0cm 0cm">
<p class="x_MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt; font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt; font-family:"Tahoma","sans-serif""> Stoves [mailto:stoves-bounces@lists.bioenergylists.org]
<b>On Behalf Of </b>Crispin Pemberton-Pigott<br>
<b>Sent:</b> Tuesday, March 8, 2016 4:26 AM<br>
<b>To:</b> Julien Winter<br>
<b>Subject:</b> Re: [Stoves] Inverse Diffusion Flames in TLUDs</span></p>
</div>
</div>
<p class="x_MsoNormal"> </p>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">Dear Julien</span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">This is a most valuable analysis. At the end I was inspired to add something that could be appended. </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">The draft of the system can be driven by a chimney. For example the Mongolian TLUD's which are among the cleanest stoves anywhere have
to be tested with some length of chimney. The manufacturers make no statements, at least no useful ones, about the chimney height. The height is forgotten by most, save the testers. </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">The mixing and the flame length and the flame sheet and the length of flamelets are all affected by the draft. China tests all stoves
with a four metre tall chimney under the national protocol. The average installed chimney height is five metres, or six, it has been hard to say with clarity. Current testing of 16 stoves for Hebei Province at CAU (BST Lab) is using a six metre chimney because
that is what was observed in Hebei. </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"><br>
<br>
</span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">Whatever result is obtained at a given level of draft, it will change if the draft is changed, especially if the pressure changes by
50%. In Mongolia the tests are done with a 2.8m chimney because the typical application is a yurt. </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">The advantage of a fan is that the pressure can be controlled at will, but the added complexity is a problem for many. </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">The humble candle is a good example of PM formation. Particles exist immediately above the flame, in the clear space, but do not exist
60mm higher up, with no flame in between, meaning it is not necessary to have one to have PM burnout. This can be demonstrated using a saucer and passing it at different heights through the gas stream. </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">Placing a glass tube above the flame that pulls it into the bottom hole can not only pretty much eliminate the PM, it can also nearly
eliminate the visible flame. There are YouTube videos of this phenomenon. The additional draft changes almost everything so it forms part of the discussion. Changing the TLUD power level changes the draft which changes the power level which changes the draft...</span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">Regards </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D">Crispin
</span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<p class="x_MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri","sans-serif"; color:#1F497D"> </span></p>
</div>
<div>
<div>
<div>
<p class="x_MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-GB">Hi all;</span></p>
</div>
<p class="x_MsoNormal"><span lang="EN-GB">Here is an interesting article about inverse diffusion flames IDF similar to what we see in many TLUDs:<br>
<br>
Blevins, L. G., Yang, N. Y., Mulholland, G. W., Davis, R. W., & Steel, E. B. 2002. Early soot from inverse diffusion flames. Prepr. Pap.-Amer. Chem. Soc., DiV. Fuel Chem, 47(2), 740-741.
<br clear="all">
</span></p>
<div>
<div>
<p class="x_MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-GB"><br>
<a href="https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/47_2_Boston_10-02_0236.pdf">https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/47_2_Boston_10-02_0236.pdf</a></span></p>
</div>
<div>
<p class="x_MsoNormal"><span lang="EN-GB">I have attached a photo of standard diffusion flame and an IDF of ethylene flames near their sooting limits. (Kumfer, BM; Skeen, SA; Axelbaum, RL. 2008. Soot inception limits in laminar diffusion flames with application
to oxy-fuel combustion. Combustion and Flame 154; 546-556)<br>
<img border="0" width="305" height="440" id="x__x0000_i1025" src="cid:image002.jpg@01D17911.91D42760" alt="Inline image 1"></span></p>
</div>
<div>
<p class="x_MsoNormal"><span lang="EN-GB"> </span></p>
</div>
<div>
<p class="x_MsoNormal"><span lang="EN-GB"><br>
<br>
<br>
In her article, Linda Blevins argues that soot forms on the outside edge of an IDF, then follows a trajectory away from the flame, and escapes oxidation. In a standard diffusion flame, soot tends to be oxidized in the tip of the flame.</span></p>
</div>
<div>
<p class="x_MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-GB"><br>
One common type of syngas burner for TLUDs has secondary air entering the gas burner through small holes. The flamelets arrising from these holes start out as a type of IDF. Syngas rises from below, so the underside of the flamelets should be more fuel rich
than the top side (which may be lean). Therefore, soot production in a TLUD burner should be greatest on the underside of the flamelets. If the flamlets coaless to form a sheet of flame across the width of the gas burner, then (most?) soot particles will
have to pass through this flame and oxidized to varying degrees.<br>
<br>
However, if we turn down the gasification rate in the TLUD, so there is not a continuous sheet of flame across the width of the burner, is there a change in the nature of soot particles in the exhause gas from the stove? Will there be a higher proportion of
polycyclic aromatic hydrocarbons vs black carbon from a turned down TLUD? Of course, when turned down the mass of soot emitted may not be very high. All the same, this is an example of why we should characterize emissions from stoves over a wide range of
power levels when assessing health risks.</span></p>
</div>
<div>
<p class="x_MsoNormal"><span lang="EN-GB">Cheers,</span></p>
</div>
<div>
<p class="x_MsoNormal"><span lang="EN-GB">Julien. </span></p>
</div>
<div>
<p class="x_MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-GB"> </span></p>
</div>
<div>
<p class="x_MsoNormal"><span lang="EN-GB"><br>
-- </span></p>
<div>
<div>
<div>
<div>
<div>
<div>
<p class="x_MsoNormal"><span lang="EN-GB">Julien Winter<br>
Cobourg, ON, CANADA</span></p>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
</html>