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Crispin,<br>
<br>
Can you please provide some diagrames or sketches of what you have
described. <br>
<br>
Secondary air is needed, so where or how and what amount is actually
doing the needed job for combustion?<br>
<br>
I like the efforts to have TLUD techniques applies to coal. Can
these efforts be somehow brought together? <br>
<br>
Who else is dealing with TLUD microgasification of coal of any type?<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 9/14/2016 12:55 PM, Crispin
Pemberton-Pigott wrote:<br>
</div>
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<div>Dear TLUD lovers</div>
<div><br>
</div>
<div>This one should warm you. </div>
<div><br>
</div>
<div>I left a design and working example of the TJ3B stove (see my
website under Tajikistan) in the town of Muminabad which is
where Caritas has a regional office focused on stove production
and other projects. </div>
<div><br>
</div>
<div>A sample arrived in Dushanbe without the essential seven
secondary air holes. The reason is that the producer feared that
CO would energy from the holes rather than air going in. As this
fear is real and people don't understand what risks that faced
in the past or now, and from what. I decided to test the stove
as is and see what would happen. Thanks to Paul Anderson for
teaching me not to live on assumptions about what does and
doesn't work. Prove it. </div>
<div><br>
</div>
<div>So I filled it with about 5 kg of Kyrgyz coal lit with mostly
soft wood. The coal size was under 27mm. <span
style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Because of the nature of the test goal I was
careful to leave out the duff smaller than 6mm. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">After ignition the fire was normal because the
bottom door was open as usual for 10-15 minutes. There was
never any smoke at all from the start. Nothing seen even
during early ignition. Part of the explanation was the use of
the lid to allow some air into the top hole on the opposite
side from the chimney creating a cross draft fire right from
the start. Otherwise I don't have a comprehensive explanation
for why it burned clean the entire time. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">The fire then burned in a normal manner as a coal
gasifier with combustion above the fuel relying on air
supplied through the fuel bed rather than above the fuel as
usual. This is how the Turkish TLUD's work. Generally they
rely heavily on the fuel particle size and hardness to get an
appropriate air/fuel ratio. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">I had to leave the door open at least a little or
else the stove would go into a very low power mode because the
control arm only uncovers three 12.7mm holes. I settled on
3mm open on one side and zero on the other. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Apart from having an extremely low excess air
level in the coke burning phase, it did remarkable well.
Obviously it needed the air below but it followed the usual
burn pattern of pyrolysing the fuel bed, about 350mm deep, in
2 hrs and then completed a slow burn of the coke over the next
five hours. Five hours after ignition the coke was again
burning on top with an outsde temperature (stove body
radiation) of 490 C. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">The excess air level in that condition was 1.5%
but the CO/CO2 ratio was only 3% which is remarkable. In this
condition the system efficiency was >80. During pyrolysis
it was as high as 7%, obviously because of a lack of air. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">So the challenge is how to improve the combustion
without offending the ideas of the customers and their well
grounded fears (people die from chimney malfunctions).</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">After some measurements and math the plan is:</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Drill one hole 20mm in diameter at the height of
the original secondary air holes. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Weld a 40x40 angle iron against the steel body
creating a triangular cavity inside it going from almost the
bottom of the body to just above the hole. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Cap the angle iron with a triangle of steel. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Weld a 45 or 90 degree steam pipe elbow to the
inside to lead the air coming through the hole downwards into
the stove body. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">This will provide preheated secondary air most of
the time, but especially when the ash is packed into the coke
and the air supply is most limited. It will direct the air
downwards so as to reach the top of the collapsed pile of
fuel. Any tendency for CO to emerge from the hole in very low
draft conditions will be overcome by heat raising the air in
the channel by buoyancy. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">The plan is to raise the excess air to at least
45%, preferably 60% in the late fire. A second change will be
increasing the stove height to bring the burn time to 9 hours
so it can heat a school classroom for a whole day on a single
load</span><span style="font-family: Calibri, 'Slate Pro',
sans-serif, sans-serif;"></span><span style="font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif;">. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">There is a picture of the stove in the Model 3
folder under Tajikistan. In the attached photo the top number
is the efficiency as a space heater. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">We will test this product in some school
classrooms this winter. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">The lesson is that it worked far better than I
expected, the secondary air holes did not render the
combustion 'terrible'. It never smoked that we could see from
beginning to end. The final version will address the evident
fear of the customers. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">It is worth noting that this solution was
recommended to the Turkish stove producers after lab tests
showed they were all short of air for great periods of time,
hours, during which PM bursts were seen at very low EA levels.
None adopted it. </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;"><br>
</span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Regards </span></div>
<div><span style="font-family: Calibri, 'Slate Pro', sans-serif,
sans-serif;">Crispin </span></div>
<br>
<br>
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