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Chrispin's message below is very useful and confirms that there are
TLUDs that can end without smoke (and some are smokey). <br>
<br>
1. It would be useful if we could get more info from the Indonesian
testing. Which of the tested TLUDs were ending with smoke? Not so
important to know the brand names, but to study the stove
characteristics so that the causes of the smoke can be determined
and then corrected. <br>
<br>
At this point I will disagree with Crispin's explanation. This
difference of thought can be settled by science, and I am happy if
he is correct. But I offer a different PART of the explanation.<br>
<br>
It is easy for all of us to agree that smoke from TLUDs at the end
(or at other times) is mainly because of loss of the secondary
flame. Issues are 1) insufficient gases, 2) loss of the "pilot"
or sustaining flame/spark, and factors (gust of wind, some
difference in the fuel for a moment) that cause those situations.<br>
<br>
My scientific disagreement relates to this comment (empahsis added):<br>
<blockquote type="cite"><span style="mso-fareast-language:EN-US">they
[TLUD stoves] have produced all the tarry gases they will, and <b><u>it
has been cracked in the hot char</u></b>. </span></blockquote>
That cracking situation occurs in downdraft gasifiers that have a
hot bed of char through which the pyrlolytic gases must past.
Check those resultant (post -charcoal) gases and see that they are
quite clean and (with some filter, cooking and maybe scrubbing) they
can go to internal combustion (IC) engines. These are clear gases,
even when cooled for use in IC engines.<br>
<br>
But the hot TLUD gases are never that clean. They are transparent
while still hot in the TLUD chamber above the created char, but if
allowed to cool, they will become visible and will be called
"smoke". Without the fire of the secondary combustion, smoke will
be emitted.<br>
<br>
The cracking of the pyrolytic gases ("smoke") requires passing
throught a much hotter bed of charcoal than is found in TLUD
stoves. (Tom Miles and probably some others can comment on the
temperatures in the char-bed of downdraft gasifiers where some air
for O2 is entering to burn (oxidize or char-gasifiy) the char.)<br>
<br>
I do not know of any studies specifically analyzing the TLUD gases
while passing through the char layer or in the area between the char
and the secondary combustion zone. Probably has been looked at
somewhere. <br>
<br>
Quick proof of the smokey gases in a WELL-FUNCTIONING TLUD (which
will end without any released smoke) is to extinquish the secondary
flame and see the billowing smoke. Be ready to relight it quickly
!!!!<br>
<br>
So, I am delighted with Crispin's observation about some TLUD stove
models being consistently functional without smoky incidents at the
end. Those are the vast majority of the TLUD stoves in use.
(Poorly functioning stoves do not get used or accepted.) We are
expecting TLUD stoves to have a great year in 2018 as more and more
Stovers join these efforts.<br>
<br>
Season's Greetings to all !!!<br>
<br>
Paul<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 12/25/2017 6:21 PM, Crispin
Pemberton-Pigott wrote:<br>
</div>
<blockquote type="cite"
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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Dear
IH<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Some
TLUD’s have a smokeless conclusion to their combustion
cycle. I found it interesting to see the difference. We were
testing a lot of stoves (30?) for the Central Java Pilot and
there are definitely two groups of TLUD’s: those that end in
a cloud of smoke that require one to jump and run, and the
others which have no smoke surge at the end at all.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">It
is the latter category that are processing the biomass at a
temperature above 500C. That is the secret. When that is
done, they have produced all the tarry gases they will, and
it has been cracked in the hot char. The distillation gases
are produced immediately below the red hot char so the
processing can be above 550 at all times once it is lit
well.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">This
clean ending permits the TLUD to be used indoors with ease.
Many thousands are being used following the success of the
pilot project.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Crispin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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