<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Crispin,<br>
<br>
I have no basis for doubting nor the time or talent for reviewing
your calculations. If someone does have revisions or corrections,
I hope they speak up right away.<br>
<br>
Otherwise, here is my comment:<br>
<br>
Concerning the issue of what is the heat lost (not liberated) if CO
from charcoal escapes instead of being burned, you have illuminated
my (our) understanding.<br>
<br>
THANK YOU, Crispin, for once again providing technical and
quantitatively supported excellent information!!!! You are (IMO) a
<u>major asset</u> to this Stoves Listserv and to our entire
community of Stovers. <br>
<br>
And a further question: In a "typical" charcoal stove that is
generating dangerous amounts of CO, what percentage of the consumed
carbon is "well burned" (and becomes CO2) versus the carbon that is
only transformed into CO? The reply might need to give some range
of values or qualify the responses relating to a "high heat"
charcoal fire versus a "low heat" charcoal fire, probably with the
latter being proportionately much more of the carbon ending up as
CO, with a corresponding 75% loss of the heat value for that amount
of charcoal.<br>
<br>
There is a big difference between (hypothetical numbers follow) 50%
of carbon going to CO instead of CO2 (with the loss of 75% of the
heat value of half of the carbon [75% of 50% = 38% lost heat) versus
only 5% of carbon going to CO (75% of 5 % = 4% lost heat). Of
course, it is the CO that can kill you that is more important than
some amount of lost heat.<br>
<br>
Comment: We are discussing "char-gasification", the oxidation of
solid carbon (but as charcoal it is not necessarily pure) into
either CO or CO2. The O2 that enters as primary air can result in
either CO or CO2. The role of secondary air is a very different
story for char-gasification than it is for the combustion of
pyrolytic gases as in the context of TLUD micro-gasifiers.<br>
<br>
Answers / comments from anyone would be appreciated. <br>
<br>
Paul<br>
<br>
<pre class="moz-signature" cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072
Website: <a class="moz-txt-link-abbreviated" href="http://www.drtlud.com">www.drtlud.com</a></pre>
<div class="moz-cite-prefix">On 8/3/2015 2:02 PM, Crispin
Pemberton-Pigott wrote:<br>
</div>
<blockquote
cite="mid:COL401-EAS42826D8900152FF08579B8AB1770@phx.gbl"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<meta name="Generator" content="Microsoft Word 15 (filtered
medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.EmailStyle18
{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:70.85pt 3.0cm 70.85pt 3.0cm;}
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="color:#1F497D">Dear Roberto<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">It is unlikely
that you will be able to burn charcoal without any CO2 at
all. </span></p>
</div>
</blockquote>
<br>
<blockquote
cite="mid:COL401-EAS42826D8900152FF08579B8AB1770@phx.gbl"
type="cite">
<div class="WordSection1">
<p class="MsoNormal"><span style="color:#1F497D">In the centre
of a charcoal flame, under the middle of the pot, there is
often a very high CO2 level, but it is so hot, excess C is
available and it is absent of free oxygen so it breaks
apart to make 2 CO. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">If you can
estimate the mass of CO2 and the mass of CO you can
calculate the difference. C to CO2 is 33 MJ/kg (close
enough) and C to CO is a bit more than 8. So you lose ¾ of
the available heat energy if you fail to burn the CO to CO2.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">For 600m of
char, (assuming 85% carbon) the loss would be 32.8 x 0.85 x
0.75 x 0.600 = 12.6 MJ loss<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Or 29.5 MJ/kg
for the char x 0.6 kg to get the available heat = 17.7 MJ<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">And<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Subtract the CO
loss: 0.600 kg x 0.85 carbon x 75% x 32.9 carbon heat =
12.6MJ loss, the same thing. Heat released by burning C to
CO = 5.1 MJ. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">If you have a
portion of the gas as CO2 and another as CO, you can
pro-rate the heat available as ‘yielded’ or ‘lost’ according
to CO/(CO2+CO) and CO2/(CO+CO2) times the carbon mass times
32.9 MJ/kg.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The CO loss is
closer to 74.5 % of the CO2 energy if you really want to be
picky.</span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Crispin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I want to know what is
the difference in combustion efficiency between burning
charcoal with secondary flame (burning CO) vs burning
without secondary flame (CO escape to the chimney).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">For example, burning 3
kg in a TLUD produce 600 grs of charcoal. Then if we decide
to burn this charcoal, burning with secondary flame is more
efficient than burning charcoal with no secondary flame.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">How can I measure this
difference?<o:p></o:p></span></p>
<p class="MsoNormal"><b><span
style="font-size:12.0pt;font-family:"Arial",sans-serif;color:#000099;mso-fareast-language:ES-CL"
lang="EN-US"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US">Greetings<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Roberto Poehlmann<o:p></o:p></span></p>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
<a class="moz-txt-link-abbreviated" href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a>
to UNSUBSCRIBE or Change your List Settings use the web page
<a class="moz-txt-link-freetext" href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a>
for more Biomass Cooking Stoves, News and Information see our web site:
<a class="moz-txt-link-freetext" href="http://stoves.bioenergylists.org/">http://stoves.bioenergylists.org/</a>
</pre>
</blockquote>
<br>
</body>
</html>