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Ron,<br>
<br>
About the concrete inner (fuel) cylinder. Hard to be sure without
actually observing it, but I suspect that:<br>
1. The thermal mass is estracting heat, meaning cooler gases inside
the chamber, with risk of insufficient temperature for ignition at
the top, especially when nearing the end of pyrolysis.<br>
<br>
2. Julien and Mahbubul can confirm about this: The concrete (or
ceramic) inner cylinder does not have any of the side holes (24 in
the metal version). Such holes allow for some "pilot light" effect
after the char level is below a hole. I imagine that small holes
would be very difficult to put into a concrete cylinder. However,
maybe 3 or 6 holes could be created at strategic locations (to be
discussed). They could be created in the following way:<br>
When the concrete is being poured (or soon after), place
something like round toothpicks (about 2 mm size??) across the
concrete, sticking out both sides. (might be at a place in the
mould with holes that would leak concrete/water except that they
would soon be "plugged" with the toothpicks. When the piece is
dried, and used for the first time (or two or three times) the wood
would burn out (or be drilled out or poked out), leaving the desired
hole.<br>
Alternatively, do the same with larger diameter pieces like
chopsticks. If the holes are too large (to be determined by
experimentation), then they might be plugges slightly (in a variety
of ways.).<br>
<br>
First, let's get more understanding of the 24 "pilot light" holes in
the metal version.<br>
<br>
3. How much supply of coconut shells (hard part) is there in your
zone?<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 12/6/2017 11:55 PM, Ronal W. Larson
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:C2071001-A78F-4A52-BE93-29CB9061B66D@comcast.net">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<div class="">Julien cc List</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>Thanks
for the answers below. Good to hear that both users with and
without land see value in making char. No new questions, two
comments</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>1.
Re a concrete inner cylinder, you said below “..<i class="">but
their smoke-free combustion was less reliable, and there were
some gas burner issues to solve. “</i></div>
<div class="">It is not obvious to me why either concern should
occur, so I hope stovers everywhere could try this out. Seems
likely to be cheaper (can even maybe cast in place) and
hopefully longer lived. We know usual cheap steel has a limited
life and the best steels are likely both not readily available
and expensive.</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I
forgot to congratulate on the two metal swinging “doors” at the
bottom. Nice solution.</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>2.
Re fuels, the biochar list has had quite a lot of recent
discussion of “blue biochar” - where the source material is kelp
or other seaweeds. Bangladesh is possibly already in that
business, because of its ocean proximity. This could be a
source of employment and a way to save forests while having a
feedstock that should bring back needed minerals and fertilizer
value. Beating the price of wooden blocks seems possible.</div>
<div class=""><br class="">
</div>
<div class="">Ron</div>
<br class="">
<div>
<blockquote type="cite" class="">
<div class="">On Dec 6, 2017, at 10:05 PM, Julien Winter <<a
href="mailto:winter.julien@gmail.com" class=""
moz-do-not-send="true">winter.julien@gmail.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div dir="ltr" class="">
<div class="">Hello all;</div>
<div class=""><br class="">
</div>
<div class="">Thanks for you comments on the Akha-Biochar
Project in Bangladesh.</div>
<div class=""><br class="">
</div>
<div class="">The cost and payback is not fully worked
out, because it will take about a year for TLUD-biochar
ecosystem to become established in community, and it
will continue to evolve. The stove costs about $20 to
make, this could be brought down as numbers of stoves
increase. Also, we are still at the stove-prototype
stage, so we can expect some modifications and fine
tuning. Payback is developing, as farmers and
gardeners discover the value of biochar for food
production. We have "Farmer Biochar User Groups" that
are conducting field trials, so they can learn from
first-hand experience what biochar can do for them.
There are also graduate students involved in gathering
evidence to make recommendations on optimum application
rates. It could take a couple of years at any one
location for the local population to be able to place
their own value on biochar, and what they are willing to
pay for it. </div>
<div class=""><br class="">
</div>
<div class="">Whether people use the char themselves or
sell it depends on their personal opportunities. There
are many families that are landless. Presently, they see
char sales as a way to earn cash or barter. They think
that is a great idea; save fuel, cook faster, AND make
biochar! People with land, especially farmers, see
biochar as a way of making permanent improvements to the
quality of their land, so expect that using biochar
could have very substantial impact on their family's
economic well being.</div>
<div class=""><br class="">
</div>
<div class="">
<div class="">I have been advocating using biochar in
composting, or mixing it with manure before it goes
onto the field. We need work on using it in human
waste management.<br class="">
</div>
<div class=""><br class="">
</div>
<div class="">There is no shortage of good soil
scientists and agronomists in Bangladesh to work on
biochar technology. </div>
</div>
<div class=""><br class="">
</div>
<div class="">The outer concrete cylinder of the Akha
stove is cast. We have made stoves with concrete
reactors (lined with clay slip), but their smoke-free
combustion was less reliable, and there were some gas
burner issues to solve. That is not to say that
concrete reactors will not work, but they need quite a
bit of research and development, and a laboratory.
Metal TLUD reactors, on the other hand, are well
understood. About 24 small holes in the side wall of
the metal reactor make the gasification of chunks of
wood more reliable, and less prone loosing the gas
flame. We use cast concrete (rather than clay) because
it is easy to get concrete rings with flat surfaces at
the top and bottom. The concrete components are made
specifically for the Akha. There are many small
business around who can cast concrete. </div>
<div class=""><br class="">
</div>
<div class="">Mahbubul has been working with different
ratios of Portand cement, sawdust and biochar dust in
the concrete. The more organics, the lower the heat
capacity and heat conductivity of the stove body. Micro
porosity is supposed to make concrete more resistant
heat by providing spaces for minerals to expand into.
Obviously there is a trade-off between adding organics
and strength of the concrete. Different recipes are
being tested in the field. It is all trial and error.</div>
<div class=""><br class="">
</div>
<div class="">Mahbubul has also worked with local ceramic
artisans to make the massive stove components from
clay. There very skilled people to work with, and
kaolinitic clay, so ceramic components are possible.
The more metal components on the stove that we can
replace with ceramics the better, because all metal in
Bangladesh is imported.</div>
<div class=""><br class="">
</div>
<div class="">The Akha is about 25% more efficient than a
traditional stove. The Akha has gone through a
water-boiling test at a laboratory in Dhaka, and was
about 30% efficient at getting energy from wood into the
water. The main view that the Akha saves 25% of the
wood comes from household feedback. That is what the
women tell us.</div>
<div class=""><br class="">
</div>
<div class="">The Akha-Biocahr Project has funding for its
current intervention until 2019. It is enough to see if
the TLUD-biochar technology will take root. If it does,
then the technology may spread all by itself as local
entrepreneurs see an opportunity. In fact, I think that
if these technologies viable, then they will out of our
control and unstoppable. The 'market' is 25 million
homes. All the same, I am trying to raise money so that
Mahbubul and crew remain as proponents and stakeholders
in what they started. There is work to be done in
developing compressed fuels, because there is not enough
wood in the country. We need to monitor the impact on
forest cover, and make sure that poorest households
don't become energy-starved if the price of wood goes
up.</div>
<div class=""><br class="">
</div>
<div class="">One other thing that will push TLUD-biochar
technology forward is that sea-level rise could flood a
third of the country, so soil productivity needs to
increase.</div>
<div class=""><br class="">
</div>
<div class="">Cheers,</div>
<div class="">Julien.</div>
<div class=""><br class="">
</div>
-- <br class="">
<div class="gmail_signature">
<div dir="ltr" class="">
<div class="">
<div dir="ltr" class="">
<div class="">
<div dir="ltr" class="">Julien Winter<br
class="">
Cobourg, ON, CANADA<br class="">
</div>
</div>
</div>
</div>
</div>
</div>
</div>
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