<div dir="ltr">I agree with Crispin and Ron that gr/min needs firepower to guide stove development.<div><br></div><div>Best,</div><div><br></div><div>Dean</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, May 25, 2015 at 9:53 AM, Ronald Hongsermeier <span dir="ltr"><<a href="mailto:rwhongser@web.de" target="_blank">rwhongser@web.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
Dear Dean,<br>
<br>
It appears that the parameters for the WHO PM2.5 standard is 2mg/min
of _what_ _burning_ _level_ (i.e., we need a wattage parameter of
some type)? When an Italian university study concluded that an
average unfiltered cigarette at human-puffing speed (i.e., smoked in
around 5 minutes) produced more particulate than a modern, properly
running 250KW diesel engine fully loaded for an hour, it is
important to link those 2 mg with an amount of fuel combusted in
that minute, don't you agree? What is that parameter? Crispin
obliquely referred to this earlier along in this discussion by
saying to decrease particulate you just have to go to a smaller
stove. There is a limit for every stove "bore" below which clean
burning (however that's defined) will not be maintainable. And with
airspeed (pressure differential), it's the same thing, there is an
upper limit at which you will have excess air for a given bore. <br>
<br>
Well-made charcoal left that particulate somewhere else-- in spades
-- probably in the air.<br>
<br>
regards,<br>
Ron<br>
P.S. Somehow I seem to be getting a feeling that the WHO standard is
not being chosen for proven health purposes, but rather for certain
types of fuels to be ultimately shown to be by definition "too
dirty". <br>
<br>
<div>On 25.05.2015 17:12, Dean Still wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi Alex,
<div><br>
</div>
<div>The best TLUD with a fan patterned after the Tom Reed
design, using a clean burning brand of heating stove pellets,
started with alcohol gel, seemed to do better than the new WHO
standard of less than 2mg/min of PM 2.5. But most well tuned
TLUDs we test are approximately around 4 to 10. And the
untuned TLUD, of course, can be much worse. This is from
gravimetric testing which catch a lot more PM2.5 than light
scattering tests. The ISO/IWA requires gravimetric testing.</div>
<div><br>
</div>
<div>Well made charcoal burns without significant emissions of
PM 2.5 and a charcoal stove met the WHO PM2.5 standard.</div>
<div><br>
</div>
<div>Using 'real wood' is a bigger challenge. Not as clean yet.
But dedicated TLUDers are experimenting diligently!</div>
<div><br>
</div>
<div>Best,</div>
<div><br>
</div>
<div>Dean</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sun, May 24, 2015 at 11:18 AM, alex
english <span dir="ltr"><<a href="mailto:aenglish444@gmail.com" target="_blank">aenglish444@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<p dir="ltr">Torrified wood has most of it's volatiles. I
would expect the gases to have a higher CV and wider range
of flame stability when used in a premix burner. Just
guessing this has no relevance to cooking stoves.<br>
Dean, what is the range, cat pee best to worst PM
emissions, that you have measured from any and all tluds
when burning dry wood pellets?<br>
Alex</p>
<div class="gmail_quote">On 2015-05-24 1:53 PM, "Dean Still"
<<a href="mailto:deankstill@gmail.com" target="_blank">deankstill@gmail.com</a>>
wrote:<br type="attribution">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Dear Ronald,
<div><br>
</div>
<div>Thanks for your helpful comments. Charcoal
without remaining wood in it doesn't make smoke but,
of course, wood really likes to smoke. With biomass
the preparation including recipe, drying, pellet
size, etc. makes a big difference in emissions when
trying to get down to the very low levels needed to
protect health. I'm making some torrified pellets
and will report back after testing under the hood.</div>
<div><br>
</div>
<div>All Best,</div>
<div><br>
</div>
<div>Dean<br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, May 23, 2015 at
3:52 PM, Ronald Hongsermeier <span dir="ltr"><<a href="mailto:rwhongser@web.de" target="_blank">rwhongser@web.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Dear
Dean,<br>
I may seem like I'm harping here, but now
that you've said a bit more, you've
mentioned a couple of factors that I have
noticed in my limited experience without a
hood and therefore without concrete
parametric analysis, but for which I can
give some postulates.<br>
<br>
1. The wood-gas stove in design mode depends
on a uniform fuel "chunk-size" which
promotes a level "pyrolysis" front(planar)
migrating towards the bottom of the stove.
If that plane is broken by dis-uniformity in
the fuel or overly large gaps between the
fuel pieces, you will get a spot drop in
temperature along with glowing fuel which
will migrate unevenly towards the bottom of
the stove, breaking the pyrolysis front and
sometimes dropping the mean temp inside the
burning chamber such that the rising wood
gas will no longer be close enough to
critical temp that the onset of 2nd-ary air
will ignite it.<br>
<br>
2. 1. would be consistent with the bark
observation. Bark generally has lots more
minerals and less energy per unit mass. Did
you/they assure dryness level of the bark?
Were the pieces between
(cross-section/10-20) of the stoves throat?
Do you mean pellets from eucalyptus wood or
when eucalyptus oil is poured on the fuel?
Off the shelf kerosin burners here in
germany are strictly regulated as to what
you may or may not burn in them. If it is
smoking it is either wrong fuel, design flaw
or user error.<br>
<br>
3. Pellets pack closely, so if they are
smoking, usually the problem can be fixed by
either turning up the fan a bit or putting
some chimney length between the secondary
air and the pan to increase the draw. (i.e.,
the primary air is probably not of
sufficient pressure to deliver enough O2 to
the pyrolysis front to keep it hot enough
such that it will ignite upon contact with
the secondary air.)<br>
<br>
4. Because torrefied pellets are partially
reacted, they may be somewhat less dense and
especially because the ends will be cleaner,
they may not resist airflow as much, which
may help somewhat with 3. above. I would
expect them to act very similar to dry
pellets, except for the difference in
density.<br>
<br>
regards,<br>
Ronald von Aftermidnighttimeforantibiotics
(and bed)<br>
<br>
<br>
<br>
<br>
<div>On 23.05.2015 23:49, Dean Still wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Dear Ron,
<div><br>
</div>
<div>We had three women interns here at
the research center for a summer who
found cleaner burning recipes for the
TLUDs gathered from the surrounding
forest. Some things like bark make
smoke, etc.</div>
<div><br>
</div>
<div>Many pellets smoke when using
eucalyptus, etc. Different mixtures of
kerosene make more or less smoke in
off the shelf stoves.</div>
<div><br>
</div>
<div>I'm wondering if torrified pellets
will burn cleaner than normal pellets.</div>
<div><br>
</div>
<div><br>
</div>
<div>Best,</div>
<div><br>
</div>
<div>Dean</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, May 23,
2015 at 1:28 PM, Ronald Hongsermeier <span dir="ltr"><<a href="mailto:rwhongser@web.de" target="_blank">rwhongser@web.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Hi Dean,<br>
I remember that there was a
proposed university program (W.
Virginia or the Carolinas??) In
view of the deaths(not _many_ but
tragic) that have taken place due
to off-loading of pellets at some
European ports (CO in the hold)
The torrefaction could lead to a
more inert fuel. That's hopeful
speculation on my part however.
You would be transporting some
less bound water and the energy
density is better than regular
pellets in addition to the lack of
liquid or vapor H2O absorption
issue mentioned before-- these
would lend efficiencies in the
logistics end of things and an
even more uniform fuel than
regular pellets, which tend to
absorb quite a bit of water here
in the damp winter weather...<br>
I have to admit that I'm a bit
puzzled as to what you mean by
cleaner fuel recipes. What
specific pollutant are you
interested in or are you talking
about particulate?<br>
If you aren't choking the burn by
putting the pot too close, you
should be getting a very clean
burn with a TLUD?!?<br>
<br>
regards,<br>
Ron<br>
<br>
<div>On 23.05.2015 22:01, Dean
Still wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi Ronald,
<div><br>
</div>
<div>I'll keep looking. I
think that we shouldn't
forget cleaner fuel recipes
as part of the solution.
<div><br>
</div>
<div>Best,</div>
<div><br>
</div>
<div>Dean</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On
Sat, May 23, 2015 at
12:33 PM, Ronald
Hongsermeier <span dir="ltr"><<a href="mailto:rwhongser@web.de" target="_blank">rwhongser@web.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Hi
Dean,<br>
I did some searching
around on the
internet several
years ago on this
topic.<br>
I'd like to try
torrefied stuff as
well, but I struck
out at that time.<br>
No idea where to
find them.<br>
The main advantage
that I picked up on
at that time was
that they should be
relatively inert as
to picking up extra
water after they
were pelletized.<br>
Cleaner burning than
what?<br>
clean burning is a
control issue, not a
fuel issue as far as
I understand. If I
understand the
concept correctly,
it's like using part
of the large
molecules initially
broken out (cracked)
by the heat in the
reaction vessel to
coat the surfaces of
the remaining
unpyrolized
material. This
should burn quite
okay in a TLUD.<br>
<br>
regards,<br>
Ronald von
Nasennebenhöhlenhölle
(but I'm coming
back)<br>
<br>
<br>
<div>On 23.05.2015
20:56, Dean Still
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi
All,
<div><br>
</div>
<div>I'd like to
try torrified
pellets in a
TLUD under the
emissions
hood.</div>
<div><br>
</div>
<div>Any ideas
on where to
find them?</div>
<div><br>
</div>
<div>Or if it
should be
cleaner
burning?</div>
<div><br>
</div>
<div>Best,</div>
<div><br>
</div>
<div>Dean</div>
</div>
<br>
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