<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Crispin,<br>
<br>
For maybe 150 years engineers have been able to make LARGE gasifier
systems work quite well. 20 kW is quite large in comparison to the
cookstove needs.<br>
<br>
Without some external verification, let's agree to differ as to
whether (and how) a migratory pyrolytic front can move upward is
such a device. It can move up somewhat, but if it is to be a
continuous process, it cannot reach the top and stay there. So,
the system requires that the fuel load be occasionally or
progressively moved downward.
<blockquote type="cite"><span style="line-height: initial;">"Air
& biomass move in counter current direction as shown in
fig-1."</span></blockquote>
And that means that the pyrolysis zone stays close to one location,
and that is easiest and most likely at or near the bottom. I have
no access to his technology, so I cannot confirm that what you say
is correct. <br>
<br>
Bottom LIT is not the issue. It is Bottom BURNING. Note that
Top-LIT is significant BECAUSE THE PYROLYSIS FRONT MOVES AWAY FROM
THE TOP, AND DOES NOT STAY THERE. I have written (see
"Micro-gasification Terminology..." at my website) that I should
have named it "MPF gasifier" to capture in the name the fundamental
difference from all other gasifiers. TLUD is Top-LIT and the front
moves downward and is not burning at the top of the pyrolyzed fuel
now-char. Bottom-lit is ignited at the bottom and the fire that
makes the heat for pyrolysis stays at the bottom, being bottom
BURNING.<br>
<br>
Look at his Figure 1 again. At the bottom is oxidation. Where
the heat is generated for driving the pyrolysis, which is occurring
higher up. But that is anoxic pyrolysis (without oxygen). In the
TLUD, there is oxic pyrolysis (glowing or "flaming" pyrolysis), and
THAT is the layer that moves. And THAT is the layer that requires
that O2 can reach it from below. But in Figure 1, the O2 is
consumed in the oxidation zone at the bottom. <br>
<br>
So, in some ways, we are discussing two quite different processes,
but both are forms of pyrolysis. <br>
<br>
Tongue in cheek: Maybe I should have called it Migratory OXIC
Pyrolytic Front, or shortened to MOPF. That would be more
precise. But then the other systems should need to put in the "AP"
for "Anoxic Pyrolysis" to show that they are different from the MPF
of TLUD technology. <br>
<br>
For clarity, please note: AP (Anoxic Pyrolysis) occurs where a
quantity of biomass becomes heated. Commonly this is in large
piles of wood in traditional charcoal making, or inside of a barrel
that is being heated in a retort. Basically all of the biomass is
being warmed at the same time. Therefore, much heat is needed to
bring the whole quantity up to zero moisture and then torrification
and then pyrolysis temperatures. Adam retorts send off plumes of
basically steam at the start, and then later have massive amounts of
pyrolytic gases coming off.<br>
<br>
In contrast, OP (Oxic Pyrolysis) occurs where a small quantity
(actually a rather thin layer) of biomass becomes heated because
small amounts of combustible gases are burned in a pyrolytic zone or
front. The OP process cannot remain in that position because it
will soon burn off all of the combustible gases and then the oxygen
would be in contact with the hot carbon (char) that was created, and
that would be char-gasification, not pyrolysis. So the front moves
downward just a small distance, in relation to the incoming flow of
air with O2. The MOPF is quite thin but is very distinct. <br>
<br>
Well, wrestling with this terminology has helped me for future
discussions about different types of gasfiers. <br>
<br>
By the way, to all readers: This is discussion is about
gasification AS IT OCCURS IN VARIOUS TYPES OF GASIFIERS. Applying
these comments (such as up-draft and down-draft) to common burning
such as a bonfire or a simple (early style) rocket stove would be
out of context. Gasifiers are based on <u>controls </u>of
drying, torrification, pyrolysis, char-gasification, and combustion
of combustible gases. Common burning has all of those processes
intermingled and not as controlled. Control is what makes gasifiers
so successful for clean combustion. The need for control also is
what adds costs and operational issues to gasifiers versus 3-stone
fires or simple "combusition-in-a-container stoves."<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 11/27/2015 6:38 PM, Crispin
Pemberton-Pigott wrote:<br>
</div>
<blockquote
cite="mid:COL401-EAS1810DAC8A4BCC414FC5FC61B1020@phx.gbl"
type="cite">
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">Dear Paul</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">Are you saying the system
described by Hirendra can't be made to work? It doesn't make a
gas that can be burned without getting the water out, agreed.
The gas has a high energy content. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">From the link:</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">"TYPES OF GASIFIERS: Generally,
gasifiers are of four types. i) Updraft- in which the biomass
is fed from the top & air at particular BST is pushed from
the bottom. The gaseous products are drawn from the top of the
gasifier for cooling & cleaning. Air & biomass move
in counter current direction as shown in fig-1."</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">The sketch shows the position of
the pyrolysis layer and it is not at the top, and it is
covered by fuel, and you can buy one. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">The fuel is indeed placed on top
in large quantities, it does not need to be added frequently
(we can quibble about the meaning of 'frequent') and the MPF
moves upward. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">So, what to say? I described it,
Hirendra makes them, and it is described in the paper, though
he was not describing his own product in detail. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">I find it interesting that you
were not able to get the system to work except as you describe
below. Do you think it is because of the small size? He gives
as a lower limit 20 kW though when discussing the system with
me he did not indicate why. As indicated in my message the gas
is very wet and requires drying. You note that it was too wet
to burn directly which confirms this need when operated with
the MPF in the middle of the fuel pile and you changed the
fueling behaviour to maintaining a thin layer on top. That is
a different approach, in my view. If it is maintained
continuously, how is the moisture level different? Hirendra's
paper mentions that the BLUD method can deal with a 'higher
fuel moisture level'. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">On reflection I don't see why it
should not be bottom lit in which case it is correctly
described as a bottom-lit up-draft device. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">For those with an interest,
Anton Soedjarno in Yogyakarta makes a fluidised bed gasifier
which is also fed from the top through a trapdoor with quite
large fuel particles: 1/2 to 1/4 of an oil palm 'empty fruit
bunch' (OPEFB). This approach greatly reduces the need for
dealing with the tars contained in the UD gas. Anton says it
doesn't make tars, actually, and it is burned directly in an
engine. The pyrolysis zone heat is used to create steam in a
parallel chamber to drive the process which is a pretty cool
idea. The reactor is quite tall. </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">Regards </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">Crispin </span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;"><br>
</span></div>
<div style="width: 100%; font-size: initial; font-family: Calibri,
'Slate Pro', sans-serif, sans-serif; color: rgb(31, 73, 125);
text-align: initial; background-color: rgb(255, 255, 255);"><span
style="line-height: initial;">Dear Crispin,</span></div>
<div id="_originalContent" style="background-color: rgb(255, 255,
255);"> <br>
Please check my publication in <i>Boiling Point</i>, 2007
(eight years ago), available at my website in Quick Picks or
directly at<br>
<br>
<a moz-do-not-send="true" class="moz-txt-link-freetext"
href="http://www.drtlud.com/wp-content/uploads/2012/08/BP53-Anderson-14.pdf">http://www.drtlud.com/wp-content/uploads/2012/08/BP53-Anderson-14.pdf</a><br>
<br>
It discusses both TLUD and AVUD methods. The AVUD method is the
basis of the Chip Energy Biomass Furnace (in the range of
200,000 BTU or 50 kW thermal). And I have made AVUD functional
in as small as a gallon container (4 liters). And several
hundred of the Chip Energy Biomass Grill were made and sold
(with a plancha top). <br>
<br>
Contrary to what you wrote about the system that you mention:<br>
1. The new fuel on top cannot be piled on in large
quantities. Reason: The heat that rises up to the new fuel
will first dry the fuel, and then torrify and eventually
pyrolyze. too much fuel to be dried at one time results in
high moisture in the gases, capable of making them
non-combustible until getting to torrification temperatures.<br>
<br>
2. Therefore, some degree of frequent fuel feeding is needed.
Works great while the user is happy sitting there feeding
occasionally. OR if the user has the money to pay for
automatic feeding. <br>
<br>
[Now that pellets are obtained so easily in so many places, I
should probably return my attention to this type of unit plus
some small automatic fuel feeder. Related to the Chip Energy
Biomass Grill. Anyone interested in this should write to me
directly off-line at <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a> ] <br>
<br>
3. In the AVUD processes, there is not any upward MPF
(migratory pyrolytic front) because the pyrolyzed fuel keeps
collapsing onto the lower char bed and air-inlet/grate. Also,
any primary air entering is into a bed of hot char where the O2
will be consumed, leaving nothing of O2 to go up to the
pyrolytic front, therefore no flaming (glowing) pyrolysis as is
found in TLUD stoves. Instead, AVUD has retort style pyrolysis
unless the char is being removed and the fuel is getting low
enough to receive some of the O2, which is the case in the Chip
Energy Biomass Furnace, which is a wonderful char maker and can
run 24/7 for days and days.<br>
<br>
4. This is BB gasification, which is Bottom Burning. It is
not related to being LIT at the top or at the bottom. It is
Bottom BURNING. [Anything that is Bottom LIT is by definition
also Bottom Burning, so that is why I dislike the insinuation
that BLUD (which is BBUD with static location of burning) is
anything like a TLUD technology.] <br>
<br>
Bottom BURNING is the case of virtually all gasifiers until Tom
Reed and Paal Wendelbo built TLUDs that are LIT a the top. But
the pyrolysis does NOT STAY at the top. It eventually gets to
the bottom and becomes BB (and without any further MPF
activity). And the combustion processes transition over from
MPF to BB Bottom Burning.<br>
<br>
5. You put Chakrabarti's paper at your website. <br>
<a moz-do-not-send="true" class="moz-txt-link-freetext"
href="http://www.newdawnengineering.com/website/library/Papers+Articles/Chakrabarti,%20H/BIOMASS%20GASIFICATION%20Hirendra%202013.pdf">http://www.newdawnengineering.com/website/library/Papers+Articles/Chakrabarti,%20H/BIOMASS%20GASIFICATION%20Hirendra%202013.pdf</a><br>
You are welcome to put mine from Boiling Point 2007 there also.
People correctly listen to and read what you provide, and we all
want what you write and say to be as accurate as possible.<br>
<br>
Paul<br>
<pre class="moz-signature" cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072
Website: <a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="http://www.drtlud.com">www.drtlud.com</a></pre>
<div class="moz-cite-prefix">On 11/27/2015 3:41 PM, Crispin
Pemberton-Pigott wrote:<br>
</div>
<blockquote
cite="mid:COL401-EAS48708C4C14BC7934278F938B1030@phx.gbl"
type="cite">
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">Dear Paul</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">There is another way to operate the TLUD which
is what the aforementioned Hirendra Chakbarti's company
makes. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">Start the stove in the regular manner. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">When the pyrolytic front is well established
start loading fuel on top but not a thin layer - lots. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">The MPF burns to the bottom and the ignited
bottom of the net fuel burns upwards. For a short time it
has two fronts. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">The bottom burns out and the char and turns all
to ash. The upper MPF moves upwards without flaming. New
fuel is added on top to keep the front buried in the pile. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">After some time the bottom is opened on the side
and ash withdrawn, dropping the pile with the MPF somewhere
above the ash and under the raw fuel. More fuel is dumped in
top. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">This produces gas which is very wet. The gas is
drawn off by a pipe and cooled to remove the water. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">The process is continuous. It can be controlled
by means of the primary air flow. There is no secondary air
as the combustion is elsewhere. In a stable operating
condition it is a BLUD gasifier that can be operated
continuously. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">It is the inversion of the Cambodian rice hull
gasifiers I described a couple of years ago. Those feed the
fuel in from the bottom and take the rice hull char off the
top with the gas going up, and the MPF going down. It also
runs continuously. Both can be fueled episodically. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">Regards </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);">Crispin thinking this BLUD approach has not been
tried within this group of experimenters. </div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div style="width: 100%; font-size: initial; font-family:
Calibri, 'Slate Pro', sans-serif, sans-serif; color: rgb(31,
73, 125); text-align: initial; background-color: rgb(255,
255, 255);"><br>
</div>
<div id="_originalContent" style="background-color: rgb(255,
255, 255);">
<div class="moz-cite-prefix">On 11/27/2015 12:10 PM, Ronal
W. Larson wrote:<br>
</div>
<blockquote
cite="mid:234A8C82-CD92-46AA-85E6-4CC99B59AD83@comcast.net"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8">
<div class="">4. Here is an idea that I wonder if you
(anyone) has tried. (I haven’t) </div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>a.
Start a TLUD in the normal way - maximum primary air
may be best (since mostly we want high power only at
the beginning).</div>
<span class="Apple-tab-span" style="white-space:pre"> </span>b.
As soon as the pyrolysis front is clearly well
established - then add a “thin” layer of the same (?)
combustibles on the top.
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>c.
There should be no ignition at the bottom of the new
layer, as there is no oxygen there. But new pyrolysis
should occur - so increased power. The top of the new
added layer could ignite, if there is plenty of
secondary air there. </div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>The
down side of this is that you probably need to control
the secondary air so that you don’t have too much
latterm Most os us never do this. But there could be
some inherent control of the secondary (that secondary
follows primary naturally)..</div>
<br>
</blockquote>
This has been done many many times. It is a way to extend
the duration of the TLUD operation. You are correct that
causes an increase in the pyrolytic gas creation but does
not increase secondary air (except through increase of draft
from more burning gases). It is a good way to put soot on
the bottom of the pot. Note that this is anoxic pyrolysis
via the heat, with no small flames (glowing pyrolysis)
present as is found in the MPF (migratory pyrolytic front).<br>
<br>
Actually two conditions are possible.<br>
1. As you describe, while the MPF is also functional and
descending.<br>
2. After the MPF reaches the bottom (and stops because it
transitions into char-burning at the bottom). This is how
people make their unit become "continuous" (at least until
it chokes up with too much char or ash). But it requires
the very frequent attention to the feeding of the fuel,
thereby losing one of the desired aspects of TLUD batch
operation (consistent flame without needing to add more fuel
during the batch time of the MPF).<br>
<br>
Therefore, what you describe certainly has been and is
frequently done. Actually, I did that in the testing in
2005 that won the Cat Pee award at Aprovecho. Then I did
not understand it fully. Trickle feeding of fuel into TLUD
stoves does work, has pros and cons, and is likely to be
done by some individuals with or without their understanding
of why or how it works and its limitations.<br>
<br>
Paul<br>
<br>
<!--end of _originalContent --></div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a>
to UNSUBSCRIBE or Change your List Settings use the web page
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a>
for more Biomass Cooking Stoves, News and Information see our web site:
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://stoves.bioenergylists.org/">http://stoves.bioenergylists.org/</a>
</pre>
</blockquote>
<br>
<br>
<!--end of _originalContent --></div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
<a class="moz-txt-link-abbreviated" href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a>
to UNSUBSCRIBE or Change your List Settings use the web page
<a class="moz-txt-link-freetext" href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a>
for more Biomass Cooking Stoves, News and Information see our web site:
<a class="moz-txt-link-freetext" href="http://stoves.bioenergylists.org/">http://stoves.bioenergylists.org/</a>
</pre>
</blockquote>
<br>
</body>
</html>