<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Sorry to protract this discussion, but...<br>
<br>
It is not entirely fair to call a nonpremixed flame "dirty". A
nonpremixed Bunsen burner flame is typically yellow, caused by the
presence of in-situ soot. However, very little of that soot is
released from the flame. There are enormous differences between soot
in a flame and soot emitted from a flame.<br>
<br>
The candle is a classic example. Its primary purpose is to generate
soot -- without soot in a candle flame it would emit very little
light. Comparatively little of the soot that is generated is
actually emitted from the flame. Next time you are at a fancy
dinner, place you spoon above the flame and see how much soot is
released: there will be some, but surprisingly little. Put your
spoon in the flame for the same amount of time and you'll soon see
how much soot is within the flame.<br>
<br>
<div class="moz-cite-prefix">Soot within flames is often highly
desirable: it is one of the primary mechanisms for heat release. A
typical furnace runs nonpremixed flames for the sole purpose of
generating as much in-situ soot as possible to radiatively heat
the furnace.<br>
<br>
<br>
On 9/1/16 5:18 PM, Philip Lloyd wrote:<br>
</div>
<blockquote cite="mid:00d601d14aa9$d2a6cbd0$77f46370$@co.za"
type="cite">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta name="Generator" content="Microsoft Word 12 (filtered
medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]-->
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.emailquote, li.emailquote, div.emailquote
{mso-style-name:emailquote;
mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:1.0pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.EmailStyle18
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
<div class="WordSection1">
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">There
is quite a good pic of flames at various mixed levels in <a
moz-do-not-send="true"
href="https://en.wikipedia.org/wiki/Bunsen_burner">https://en.wikipedia.org/wiki/Bunsen_burner</a>.
When there is no premixing, the flame is yellow and dirty
(not all carbon is combusted, as in a candle flame). When
you get to a stoichiometric flame, all the combustion takes
place at the blue cone – the almost invisible “flame” above
it is mainly hot gas radiating; minimal combustion takes
place there.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Prof
Philip Lloyd</span><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Energy
Institute</span><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D">Cape
Peninsula University of Technology</span><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"
lang="EN-ZA">PO Box 1906<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"
lang="EN-ZA">Bellville 7535<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"
lang="EN-ZA">Tel: 021 959 4323<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"
lang="EN-ZA">Fax: 086 778 0257<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"
lang="EN-ZA">Cell: 083 441 5247<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D"
lang="EN-ZA">PA: Nadia 021 959 4330</span><br>
</p>
</div>
</blockquote>
<br>
</body>
</html>