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<DIV><FONT face=Arial>Dear Paul</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>To comment on your important question:</FONT></DIV>
<DIV><FONT face=Arial>"<FONT face="Times New Roman">How would cristobalite
formation be avoided in a direct combustion unit processing a biomass that has
an appreciable content of amorphous silica?</FONT>",</FONT></DIV>
<DIV><FONT face=Arial>I would suggest for your consideration the possibility of
adding alkaline earths or metals to the rice husks, with a view to forming
harmless silicate compounds.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>1: The first one I would try is Ca(OH)2, or "Hydrated
lime". It might have "binding characteristics" that would enable you to produce
a pellet or "Rice Hull Aggregate" if some sort, but on combustion, the CaO would
certainly react with the SiO2, to produce "Calcium Silicate" of some sort,
having the generalized formula "XCaO.YSiO2" This would tend to produce a pH
neutral ash. Or, it might also yield an ash with cementatious
properties.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>2: Another approach you might try is to add a Sodium or
Calcium Bentonite Clay to the RH fuel, firstly to act as a "binder/aggregator",
and then to act as a "Silica Getter" during combustion.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>3: You might even try sodium carbonate, as a 'silica
reactant. "</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>4: Iron Oxide has a strong affinity for silica also. If
you have a 'high iron clay", it might also be worth a try.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Note that these are not necessarily "simple suggestions."
Too much of the alkalis may cause clinkering. Significant experimentation may be
required.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Best wishes,</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Kevin</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=paul.olivier@esrla.com href="mailto:paul.olivier@esrla.com">Paul
Olivier</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=stoves@lists.bioenergylists.org
href="mailto:stoves@lists.bioenergylists.org">Discussion of biomass cooking
stoves</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, June 13, 2013 9:21
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Stoves] Burning wet
wood</DIV>
<DIV><BR></DIV>
<DIV dir=ltr>
<DIV>
<DIV>Crispin,<BR><BR></DIV>My point of departure is a top-lit, updraft
gasifier that makes biochar. Everything that I have written previously has to
be understood in this light. This could be contrasted with a direct combustion
unit, but this was not my point at all. But direct combustion units do not
have a very great appeal among the Vietnamese.<BR><BR>I do not think that I
could interest very many households in Vietnam to switch from bottled gas to a
biomass fuel if I were to ask them to directly combust biomass in their
kitchens. Most Vietnamese might not make a lot of money per month, but they
are sharp, intelligent and enterprising. They see direct combustion units
associated with poverty. They are not attracted to handling a messy biomass of
a low bulk density, and there is also a strong social resistance even against
handling loose rice hulls. This is especially true in an urban
setting.<BR><BR></DIV>
<DIV>Rice is a major export item for Vietnam, and it is grown on over 80% of
the agricultural land in Vietnam. Therefore, Vietnam produces a lot of rice
hulls. In the highland areas where rice is not grown, we find coffee husks. So
for the Vietnamese, there are these two readily available fuels. We also see
rice hulls or coffee husks in many other Asian countries. Now let me pose the
following question to you.<BR><BR></DIV>
<DIV>Do you think that you could build a small direct combustion unit that
would handle loose rice hulls and loose coffee husks as neatly and cleanly as
a TLUD? I have seen many people who try to burn these two waste products, but
there is always a lot of smoke. The coffee husk is especially nasty to
combust. When burned, it emits a strong, black, pungent smoke. I would insist
that this direct combustion unit for rice hulls and coffee husks not emit a
whiff of visible smoke at any time during its entire operation.<BR><BR>Finally
I must caution that the direct combustion of rice hulls is not ideal, since
the ash might easily contain cristobalite. How would cristobalite formation be
avoided in a direct combustion unit processing a biomass that has an
appreciable content of amorphous silica?<BR><BR></DIV>
<DIV>Thanks.<BR></DIV>
<DIV>Paul<BR></DIV></DIV>
<DIV class=gmail_extra><BR><BR>
<DIV class=gmail_quote>On Thu, Jun 13, 2013 at 8:29 PM, Crispin
Pemberton-Pigott <SPAN dir=ltr><<A href="mailto:crispinpigott@gmail.com"
target=_blank>crispinpigott@gmail.com</A>></SPAN> wrote:<BR>
<BLOCKQUOTE
style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote>
<DIV lang=EN-CA vlink="purple" link="blue">
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Dear
Paul O<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">I
am not sure why you think I am opposing the preparation of fuels. You have
mentioned it perhaps a dozen times in your last message as if it is
something I oppose. Because I have no idea why you think I oppose fuel
preparation – an essential part of most combustion I will address this
point.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Let
me set the record straight so you do not waste any more time telling me that
I oppose fuel preparation.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">I
fully agree that fuels need to be prepared. All fuels should be prepared in
some way – either tree branches cut to length for transport or split to
promote faster drying, chopping in certain cases or turning it into pellets
or briquettes for certain applications.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">I
not only fully agree with coal preparation, I have researched the correct
size that the raw coal should be in order to perform well in certain
ultra-low emissions stoves. The answer is a 10 to 15 g pellet with well
rounded edges so that it flows well under gravity without shaking or
vibration. This can be done with high volatiles coal without adding any
binder merely by getting the moisture and pressure of formation correct.
This was researched in South Africa by Prof Horsfall (Shell Coal Chair, Wits
Univ, JHB) and our fellow list member Prof Philip Lloyd. Briquetting raw
coal is an excellent way to deal with the difficult of lowering emissions
from very low priced stoves.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">What
does not work well at all, proven over and over, is making semi-coked
briquettes and trying to promote that to households as a domestic fuel. This
product, which is nearly useless for cooking, is promoted over and over as a
‘clean coal’ product. Time and again users find it is very hard to light,
requires a much larger fire to remain alight, must be refuelled much sooner
than unprocessed coal and is three times the price required the whole
industry to be subsidised. It does not ‘burn cleaner’, it makes as much PM
to light and makes more CO. To burn it correctly it has to be reduced to the
same optimal size and manufactured with the volatiles intact so it can burn
properly.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<DIV>
<DIV>
<DIV>
<DIV>
<DIV class=im>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US>></SPAN></B>If you say "dirty coal" to someone in the
industry, they will understand exactly what you mean.<SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P></DIV>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">They
will point to a coal their combustor cannot burn.<U></U><U></U></SPAN></P>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Obviously
there are coals from the edge of the field that are very difficult to burn
at all. In fact they call it ‘burned’ coal, meaning deteriorated. I was
involved slightly in the exploration of the Transkei coal fields near
MacClear in the early 80’s working with Heinemann whose PhD thesis describes
the field well. The edges of the deposits will not burn in a domestic stove.
That product is suited to >20 kW institutional stoves that are never
turned off. In short, the device is tuned to the
fuel.<U></U><U></U></SPAN></P></DIV>
<DIV>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">></SPAN>Every
body in the trade can tell you what a bad coal is, and they usually have a
good idea of what is needed to prepare it into a good coal for a specific
purpose. There are almost no coals coming out of the ground that must not be
prepared.<SPAN style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">I
am ‘in the trade’ and I think there is far too much ‘old boy understanding’
of what a good or bad coal is. The best coal I have even worked with is from
Nalaikh mine: 25% moisture, 50% volatiles, 0.2% Sulphur. This qualifies in
the old school methods as a terrible, dirty, bad
coal.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">It
is one of the cleanest burning fuels available – but not when put into a
badly made copy of a Russian wood stove. It is really hard to produce
clinkers with it (high ash fusion temperature) and is very easy to light. It
will work in a TLUD or cross draft or downdraft stove and burn clean enough
to take the PM out of the ambient air. Show me a power station running
‘clean good coal’ that will do that. The stoves being promoted had lower CO
per MJ than a new Eskom power station, lower PM and of course a much greater
system efficiency than using electricity.<U></U><U></U></SPAN></P></DIV>
<DIV class=im>
<DIV>
<P class=MsoNormal><SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN> </P></DIV>
<DIV>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>But, Crispin,
just about all coal must be prepared. Also there is extensive blending going
on. Combustors generally are not designed to handle
everything.<U></U><U></U></P></DIV></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">That
is correct – combustors are designed to handle particular fuels. Fuels are
prepared for particular combustors. We all know this. When fuels are not
matched to the stove or vice versa, it is not true that the fuels are
‘dirty’. That is my point. In the wrong stove, biomass is a ‘dirty smoky
fuel’. At a ProBEC conference once there was a lady who was just dead set
against anyone burning wood because it was ‘a smoky fuel’. It did not
occur to her that there were more options than an open
fire.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">></SPAN>Yes,
but please do not tell me the South Africans do not do extensive coal
preparation. <SPAN style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">That
is why I said nothing about that. I am not sure where you are coming from.
Coal is always prepared, usually by sizing.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV>
<DIV class=im>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>Yes, there are
power stations designed to burn coal of a 40% ash. But often they have
little choice in doing so. <SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Correct.
They design burners to go with the fuel. Until then, the fuel is ‘bad’ – is
that correct? Then it becomes ‘good’?<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV class=im>
<BLOCKQUOTE
style="BORDER-BOTTOM: medium none; BORDER-LEFT: #cccccc 1pt solid; PADDING-BOTTOM: 0mm; PADDING-LEFT: 6pt; PADDING-RIGHT: 0mm; MARGIN-LEFT: 4.8pt; BORDER-TOP: medium none; MARGIN-RIGHT: 0mm; BORDER-RIGHT: medium none; PADDING-TOP: 0mm">
<DIV>
<DIV>
<DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">>>Imagine
trying to design a biomass stove that was tuned to each type of fuel that
happened to be available…oh wait…that is exactly what is happening on this
list! What a surprise, again. Is that not exactly what you are
doing?</SPAN><U></U><U></U></P></DIV></DIV></DIV></DIV></BLOCKQUOTE></DIV>
<DIV>
<DIV class=im>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>Not at all. That
is precisely what I am opposing. <SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">What
exactly are you opposing? It is not at all clear. Are you opposing stoves
that can burn unprocessed fuels? Are you opposing stoves that only burn one
fuel?<U></U><U></U></SPAN></P>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">></SPAN>Crispin,
I challenge you to put coconut powder or fine sawdust into the best TLUD
that you can design. <SPAN style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Why
would I try to burn fine sawdust in a TLUD? There is nothing magical about a
TLUD. There are plenty of bad TLUD’s. Fine sawdust burns perfectly well in a
blown burner and there is a very fine ceramics factory in Malawi that uses
such a burner – two of them actually. Just because a fuel doesn’t burn well
in a TLUD does not mean the fuel is ‘bad’ or
‘dirty’.<U></U><U></U></SPAN></P>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>Then tell me if
air is going to flow up through this fine biomass in a uniform manner. <SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">It
is not going to, that is why a TLUD is not suitable for burning that fuel.
Use something more appropriate.<U></U><U></U></SPAN></P>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>Tell me that
there will be minimal CO2 present in the outgoing syngas. <SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Why
should we have to produce syngas? Is this based on the idea that only a TLUD
gasifier can burn cleanly??<U></U><U></U></SPAN></P>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>Also the device
you design has to be small and easy to use. It cannot occupy an entire
corner of your kitchen, and no part of it should be situated outdoors. Go
for it.<SPAN style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">That’s
silly. I will choose my own design criteria, thank you very much. The
challenge is to burn a fuel properly in a way convenient to the user.
<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV class=im>
<DIV>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>However, if we
pelletize the coconut dusk or the wood shaving, air flows up through it in a
uniform manner, and we have an incredibly simple reactor that weighs less
than 1.2 kg. It can be in continuous operation for up to 1.5
hours.<U></U><U></U></P></DIV></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">That
is one solution. Go for it. See if people want to buy it. If they do, you
have a winner. If it tests well, I will promote it. Testing will include
user acceptance, emissions and durability, cost and
controllability.<U></U><U></U></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">></SPAN>Ok,
then show me a TLUD operating on loose coconut dust or fine sawdust. <SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Why
would I bother trying to burn in in a TLUD? They are batch loaded. They are
hard to control, they can’t really be turned off. A TLUD is very
finicky about the fuel – in fact the fuel can be considered a significant
part of the stove. Fuel preparation is so onerous that when we tried late
last year to talk about ‘improved stoves’ in Central Java, the group of
women immediately, loudly and without prompting, told us firmly that we
should <I>not</I> bring to them any stove that required extensive fuel
preparation, “especially chopping wood into small pieces”. They were simply
<I>not</I> willing to do that, they said.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">It
seems someone had been there before us.<U></U><U></U></SPAN></P>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>There should be
relatively little CO2 in the syngas<SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Why
make syngas? Why not just burn the fuel? This gasifier thing is getting out
of hand. We are not trying to supply town gas we are trying to cook. If you
don’t separate the fire from the fuel many problems are eliminated.
Close-coupled semi-gasifiers avoid all sorts of problems for this
reason.<U></U><U></U></SPAN></P>
<DIV class=im>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>It should also
make a uniform biochar. <SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">What
on earth for? Having collected all the fuel and dried it, with effort, and
handled it into the stove, why would I not burn it? The economic argument
about char in the soil may well be shown, in future, to be valid. Until then
it is arm waving. If char helps soil, make a reactor that is smokeless and
make it at scale. Cheaply, locally, and apply it without transporting to the
kitchen and back. In your special circumstances, which are hardly universal,
you have a local market – go for it. Don’t advertise it for people for whom
it is completely inappropriate.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV class=im>
<BLOCKQUOTE
style="BORDER-BOTTOM: medium none; BORDER-LEFT: #cccccc 1pt solid; PADDING-BOTTOM: 0mm; PADDING-LEFT: 6pt; PADDING-RIGHT: 0mm; MARGIN-LEFT: 4.8pt; BORDER-TOP: medium none; MARGIN-RIGHT: 0mm; BORDER-RIGHT: medium none; PADDING-TOP: 0mm">
<DIV>
<DIV>
<DIV>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">>></SPAN><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">We
do not focus enough on how to design good stoves and hope that preparing
the fuel will compensate for our collective ignorance.
</SPAN><U></U><U></U></P></DIV></DIV></DIV></BLOCKQUOTE></DIV>
<DIV>
<DIV class=im>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>No, but we can
make things infinitely complicated and expensive if we do not prepare fuels
correctly. <SPAN style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">So,
prepare the fuels. Nothing wrong with that if people are willing to do
it.<U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV>
<DIV class=im>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">></SPAN>Ok, then put
Mongolian coal, of a 30% moisture content and of all shapes and sizes, into
a TLUD, and tell me if you are going to get a beautiful flame with no CO2
formation in the synas. <SPAN
style="COLOR: #1f497d"><U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">You
are mixing two things: a decent burn and gas production. No Mongolian is
trying to make syngas in a TLUD. I doubt they know what the term ‘TLUD’
means, 99% of the TLUD users. It is just a stove. It burns “</SPAN>Mongolian
coal, of a 30% moisture content and of all shapes and sizes” <SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">and
they do it hundreds of thousands of times a day. Emissions are down more
than 90% against the baseline. If they would prepare the fuel into small
round briquettes, PM would drop another order of magnitude. Is there any
other project that has a) as many TLUD’s promoted? As much reduction in the
local environmental PM? As much an advance over the baseline? As little
attention? <U></U><U></U></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV>
<DIV>
<DIV class=im>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="COLOR: #1f497d">></SPAN>The TLUD works superbly on both rice hulls
and coffee husk because these materials are uniform and generally do not
require preparation. When hulled, coffee cherries and rice hulls are at a
12% moisture, and air flows up through them within the reactor in a uniform
manner. <SPAN style="COLOR: #1f497d"><U></U><U></U></SPAN></P></DIV>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">So
what you are saying is that when the fuel is perfectly prepared, it happens
to work well with a particular type or types of TLUD. How is this going to
assist us all? We cannot prepare all the fuels available so they will suit a
certain burning technology. The technology is much easier to change than 99%
of the fuels.<U></U><U></U></SPAN></P>
<DIV class=im>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="COLOR: #1f497d">></SPAN>I venture to say the TLUD will work well
on most types of irregular biomass provided they are properly prepared. This
measn that the one stove could handle almost any type of properly prepared
biomass.<SPAN style="COLOR: #1f497d"><U></U><U></U></SPAN></P></DIV>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">An
approach specifically and heartily rejected by our target audience. They are
drowning in biomass and they are not interested in a) paying for fuel and b)
preparing it to fit what someone happens to be making as a combustor. Far
easier to change the combustor. Develop once. Buy once, problem solved.
<U></U><U></U></SPAN></P></DIV></DIV>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">That
is my point.<U></U><U></U></SPAN></P>
<P style="MARGIN-BOTTOM: 12pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Regards<SPAN
class=HOEnZb><FONT
color=#888888><BR>Crispin<U></U><U></U></FONT></SPAN></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><U></U><U></U></SPAN> </P></DIV></DIV></DIV></DIV><BR>_______________________________________________<BR>Stoves
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clear=all><BR>-- <BR>Paul A. Olivier PhD<BR>26/5 Phu Dong Thien
Vuong<BR>Dalat<BR>Vietnam<BR><BR>Louisiana telephone: 1-337-447-4124 (rings
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