July 2001 Gasification Archive

For more information to help people develop better stoves for cooking with biomass fuels in developing regions, please see our web site: http://www.bioenergylists.org

From pverhaart at optusnet.com.au Sun Jul 1 06:23:21 2001
From: pverhaart at optusnet.com.au (Peter Verhaart)
Date: Tue Aug 31 21:36:57 2004
Subject: FORUM
In-Reply-To: <008f01c0ffee$4a5bbf80$ee85a141@tedscomputer>
Message-ID: <5.1.0.14.2.20010630213457.00a73ec0@mail.optusnet.com.au>

Tom Miles, Ron Larcon, Alex English and Tom Reed.

I would like to express my great appreciation for the way you have and are
running the Stoves List. I am sure a great many like myself enjoy the
results of your efforts.

Piet

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From ronallarson at qwest.net Sun Jul 1 09:36:09 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:57 2004
Subject: Fw: Briquettes with holes (2)
Message-ID: <007a01c10232$a225ef60$e6f4b4d1@computer>

Stovers:

Several comments on the
following Friday message from Tom Duke:

1. I heard Mark Hertsgaard talk on his book
at the year 2000 ASES meeting at Madison. I strongly recommend the book -
which I also bought (autographed). Mark describes travels around the
world talking to both powerful and ordinary people - only about the
environment. I believe he found China to have the worst environment of any
place he went. I also have heard the Chinese are cleaning things up pretty
rapidly.

2. As near as I can tell, we have no one on
the "stoves" list from China. But Ralph Overend and Helena Chum from NREL
have been there. Maybe they or others who have been to China on stoves
expeditions can give their thoughts on the good and bad aspects of
these coal "honeycombs". Anyone able to report on all the important
dimensions and numbers of holes? Should there be a difference between the
appropriae "holiness" of briquettes using biomass vs. coal?

3. I first "met" Tom Duke via e-mail as the
first person to try the charcoal-making stoves idea back in 1995 (?), after I
wrote in to "bioenergy". Tom reported within days on two
really brilliant additions -

a ) half (?) filling a really
tall (4 meters?) chimney pipe (30 cm diameter?) with "sticks" and top
lighting as a barn overnight heater. With top lighting he got the usual 25% (?)
charcoal production and a very long continuous Power output. (Tom -
can you tell when and where that might be archived?)

b) Building the
charcoal-making stove entirely as two side-by-side holes in the ground (zero
capital expense). Again got good (?) charcoal production, controllable
output, low emissions. (Tom - again can you tell when and where that might
be archived? I know both preceded the start-up of "stoves")

4. On my way to Madison a year ago, I stopped
in to see Tom and family for a few hours of real talk (and lunch). We
don't hear enough from Tom on stoves because his passion is wind
generation. Small test wind generators of novel design were all over Tom's
pretty large (and lovely) farm and barn. I strongly recommend Tom to
anyone listening in who is looking for a really bright widely-read
farmer/engineer/scientist to try out new ideas. (I am talking about for
pay usually - so far his inputs have all been for free.) Tom is a lot
like Alex English (a tad older) for those of you who know Alex.

Tom - thanks for the valuable
addition.

Ron

----- Original Message -----
From: <A
href="mailto:tduke@igc.org" title=tduke@igc.org>Thomas Duke
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Sent: Friday, June 29, 2001 8:52 AM
Subject: Re: Briquettes with holes (2)

Ron:Page 163 of "Earth Odyssey" by Mark Hertsgaard has this: " I
was especially intrigued by bikes carrying the coal briquettes locals called
"honeycombs" (because of the holes drilled in the briquettes to encourage
cleaner burning). Round, black, the size of small coffee cakes, the honeycombs
were stacked by the hundreds into squat pyramids and sold off the carts for
burning in the home stoves of the poor. Honeycombs were said to be the cause of
much of China's air pollution, but where was the pollution?" Mark in in Beijing
when he is seeing the squat pyramids of honeycombs. Tom Duke
(Tom 1 day earlier wrote this - but I don't
think either went to all stovers:

Ron and stovers:The Chinese use a coal they
call honeycomb coal. It has holes drilled in it. I don't have pictures. But I
read about it in one of the books; I think it was "Earth Odyssey" by Mark
Hertsgaard, 1998, Broadway Books, New York. ISBN 0-7679-0058-8He said it was
preferred because of the quality of the burn.)
Ron Larson wrote:

Stovers:

The following is a relatively "new" topic
that I hope others can comment on - especially those who have similar
photographic or other data.

<snip>

From ronallarson at qwest.net Sun Jul 1 16:49:22 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:57 2004
Subject: briquettes with holes
In-Reply-To: <3B3D7708.00000B.15435@pentium-333>
Message-ID: <00fe01c1026f$17dbf100$e6f4b4d1@computer>

Elsen (cc: Stovers)

1. Thanks
for the quick input on this issue.

See more notes below.

<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
elk
To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Sent: Saturday, June 30, 2001 12:51
AM
Subject: briquettes with holes

<TD id=INCREDITEXTREGION
style="FONT-FAMILY: Comic Sans MS; FONT-SIZE: 10pt; PADDING-LEFT: 7px; PADDING-RIGHT: 7px"
width="100%">
>Our experience here in Nairobi indicates that the larger the
briquette the less breakage there is in transport and the lower the
amount of waste fines.

(RWL--1)
I am sure you are correct that the
extra edges can create new potential breakage problems. But I
wonder about these solutions:

a.
Maybe there could be some "rounding" - more like a donut" (both
inner and outer "edges" - a term that doesn't apply well to a
donut).
b.
Maybe there is some reduced body tensions due to better drying
characteristics (which might be the reason Richard Stanley has used the
interior hole).

>This is a simply due to the fact that there fewer 'edges' per
kilo with larger briquettes- the edge of a briquette being the area most
susceptible to breakage.

(RWL-2): This would seem to
have some upper limit. Can you describe this more in terms of
thickness as well as diameter. What are your optimum
dimensions now? Could you try holes in the way you are making your
briquettes?

>Briquettes with holes have almost double the 'edge distance'
that solid briquettes have, are much more prone to being crushed
and would certainly burn faster due to higher surface area.

(RWL-3): I
know that you use a lot of clay to prolong the burn - and your
customers like this feature. Is it possible that Richard's use of
"raw" biomass would lead to a different optimization to your
concentration on starting with charcoal fines? Might it be possible that intense burns but
with a smaller input (number of briquettes) but with higher overall
efficiency would be a better way to go? This has been the
approach of Paul Hait with his "thermal array" of charcoal briquettes.

>I would expect that only an unusually large briquette, stood
vertically in a stove with good ventilation and carefully lit from below
would exhibit any form of chimney effect.

(RWL-4):
This is a great question, that I hope you and others can look
into. Clearly, a few centimeters of heighth isn't going to create
a huge draft. On the other hand there is still some theoretically,
and the interior of the hole is creating plentiful gases, which in turn
has to create a large velocity to maintain a steady state. The
photographs show such vigorous combustion clearly.
(RWL-5) I
would like to see a test with the hole's axis lying horizontally.
I think there may still be sufficient (internal-to-the-hole and circular
symmetry) radiative heat transfer to drive a significant flame even in
that position. Anyone have any results to report?
(Photographs?) This is the geometry closest to what Paul Hait
does.
(RWL-6):
Some of us at the Pune conference will remember a talk by John Rouse -
in which he described a grate made of homemade ceramic "rods". I
am thinking of the "donuts" resting in a "non-flat" position between
these grate rods.

>On the positive side, the lower bulk density and novel
form of a briquette with a hole could be marketing
advantages.

(RWL-7): I'm not sure why that
should be the case, but will take your word for it. The
description by Tom Duke of carrying them suggest that it might be
possible to carry them easily when tied up with a single thong. I
hope Richard can comment on the marketability aspects.

(RWL-8) Others on the list
(such as Richard Stanley) may not have been on the list long enough to
know of Elsen's considerable background in doing briquette-related
research (as well as charcoal-making and charcoal-making stove
research as well). Elsen has a major business starting up in
Nairobi in the making and marketing of chrcoal briquettes. Some of
this has been with bagasse and sugar cane residue. Elsen - from
what you know of Richard's approach, do you think that making the
briquettes from sugar cane residue would be feasible - and
marketable? The part I like about this approach is that one
doesn't lose two-thirds of the energy in the initial pyrolysis. If
Richard's combustion process is complete enough, perhaps biomass
briquettes can be provided cheaper than charcoal. What do you
think?

(RWL-9) Thanks for your
input. I think we will probably be discusing this for a bit
longer. Yours can be a major factor in better undestanding
this interior hole phenomenon. Ron

>elk

Elsen Karstad
elk@wananchi.com
www.chardust.com

<TD align=middle id=INCREDIANIM
vAlign=bottom>_________________________________________________IncrediMail - Email has finally
evolved - Click
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From ronallarson at qwest.net Sun Jul 1 22:09:00 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:57 2004
Subject: Fw: Briquettes with holes
Message-ID: <000301c1029b$b47f1ba0$5c7de13f@computer>

A.D. (and Stovers):

Your comments, as usual, are
very interesting. Thanks

Before some questions, let me tell new stoves
members that you led last November's stove conference and head a major
successful Indian development group that has done some very fine stove
work. In the following, I should also mention that you and I have both
been members of a bamboo list - but your knowledge is enormously better
than anyone I know on bamboo (and a whole range of biological
topics).

More below.

----- Original Message -----
From: <A
href="mailto:adkarve@pn2.vsnl.net.in" title=adkarve@pn2.vsnl.net.in>A.D.
Karve
To: <A href="mailto:ronallarson@qwest.net"
title=ronallarson@qwest.net>Ron Larson
Sent: Friday, June 29, 2001 7:53 AM
Subject: Re: Briquettes with holes

Dear Ron,
>In one of the publications by Dr. P.D.Grover of
New Delhi, India, I saw a fat cylindrical char briquette. This briquette
fits snugly into the hollow space of the stove, so that you use just a single
briquette at a time. The briquette has 19 vertical holes, symmetrically
arranged, equidistant from each other . You ignite it from below, and once
all the cylindrical cavities are burning, you get a uniform hot front hitting
the pot kept on the stove. Dr. Grover calls it a honeycomb briquette.
We made such briquettes and tried them out. They had many disadvantages.
The very first one was the difficulty in getting all the holes burning
simultaneously.

(RWL): I know of several
other Grover technologies but was not aware of this one. Many of his stove
designs have been for charcoal making - and I wonder if this was also. I
believe it might well be a successful charcoal making design if lit from the
top. I can't be sure, but I believe that you will then find all
holes burning simultaneously. In all the charcoal-making stove tests I
have perfomed, such was the case. Stopping a burn (by smothering or using
water) has mostly shown a horizontal flat demarcation between the charcoal
and unpyrolyzed regions. I can't give a good reason for why this should be so -
but believe the Grover 19-hole unit will "draw" evenly. But it must be lit
on the top.

>Another was that this briquette did not
leave you any freedom to control the heat. In a normal charcoal stove, you can
control the heat by adjusting the number of charcoal lumps burning in the
stove. This flexibility was not available when you used the honeycomb
briquette. Initially it produced less heat, then it produced very intense heat,
as as the briquette burnt itself out, the heat ebbed. If you still needed
intense heat, there was nothing you could do.

(RWL): One of the beauties of a
charcoal-making stove is that one does have good control over power output
- by controlling the primary air. We have been getting a ratio of about
3:1 for Pmax/Pmin. But again, one has to use top lighting. Once
the primary air has been established, the power output stays quite
constant.
I am less sure that all this
will work with a solid piece with 19 holes. As you have indicated below,
it may be better to place 19 straight pieces into a cylinder in which they fit
tightly (leaving "triangular" spaces between). One may need some lateral
"communication" between the air passageways - which is not possible with the
19-hole design. But this is a needed experiment. If you have
any of these 19-hole briquettes left (or can make them still easily), I hope you
will try (with top lighting).

>In a charcoal
stove or in one using smaller char briquettes, you go on adding a few fresh
charcoal lumps or briquettes, to give a constant high heat intensity over any
length of time. However, after we had completed our studies, somebody told me
that the honeycomb briquette was not meant for a cookstove but for a stove used
for room heating! Fortunately, we don't need any room heating in Pune.

(RWL): Could
you give us some more background on the dimensions of the "Grover" briquette and
holes - and the difficulty of making them.

>In our conference in Pune, last November, there
was a paper from Asian Institute of Technology, Bangkok, describing the
production procedure of a hollow cylindrical briquette. The hollow cavity
would certainly give intense heat, as suggested by you, but in order to use that
heat effectively for cooking, all the briquettes must be vertically
oriented. In fact, even our solid cylindrical char briquettes produce the
same effect if the cylindrical briquettes are arranged vertically, packed in
such a way within the firebox of the stove, that they touch each other. The
triangular empty spaces left between the adjacent briquettes have the same
effect as that described by you for a hollow cylindrical
briquette.
Yours Nandu

(RWL): I have now forgotten the details of
that AIT paper. Could you (or they) remind me of what the results
were? (Dimensions? biomass or charcoal?) As I said in a message
immediately preceding to Elsen Karstad, I am not so sure that the stacking must
be vertical. I believe the radiative effect will be stronger than the
convective effects.
I presume that you have not used your packed
cylinder approach with top-lighting?
I am glad that you wrote
especially because I wanted to talk about using short sections of bamboo as
"one-hole-briquettes". As bamboo (any other plantss?) comes in dozens of
species and (I believe) have central holes of many sizes, it would seem that we
should be learning more about its combustion characteristics when used in short
sections. My only perception of burning bamboo is in long
sections. Could you (and anyone listening with access to dry bamboo) try
some experiments with different length to diameter ratios and oriented in the
stove in different ways (bamboo central axis
pointed both up and horizontally). I am guessing that the combustion
properties witll be improved with short
hollow sections. This should be an "easy" way also to test the flame
properties with diferent orientations and separations. If really better by
exploiting the advantages (if any) of this different form of encouraging
combustion, perhaps there could be a bigger role for bamboo in household
cooking - which I know is of interest to you..

Thanks in advance for any new data you can
add.

Ron
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Ron
Larson
To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org ; <A
href="mailto:rstanley@legacyfound.org" title=rstanley@legacyfound.org>"Richard
Stanley"
Sent: Friday, June 29, 2001 11:03
AM
Subject: Briquettes with holes

<snip>

From ronallarson at qwest.net Sun Jul 1 23:11:55 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:36:57 2004
Subject: Briquettes with holes - (R. Stanley)
In-Reply-To: <4.3.1.2.20010629093006.00e15930@mail.ilstu.edu>
Message-ID: <00db01c102a4$6e068e20$5c7de13f@computer>

Richard and all stovers:

Thanks for the answers below - I will just ask a few more questions below:

<snip>

>
> Holes: The hole has effect only when the radius of the briquette is about
> equal to its height.
> I have played with surface area to volume ratios but this simple rule of
thumb
> works quite well. The diameter of the hole is optimal at 1/4 to 1/3 the
> diameter of the briquette.
>
<snip>
>
> As to Tom Larson's concern for pyrolsis migration rates, our study,
published
> in the American Chemical society's Journal of Chemical Innovation this
past
> February, identifies two distinct kinds fo heat being generated in the
burn
> cycle.

(RWL): I tried unsuccessfully to reach this site. More after I read
the article.

>The first is a rapid rise to 800 centigrade within about 6 to 10
> minutes for five to fifteen minutes, with licking convective flames. The
> flames then die down to yeild an infrared glow in the core for the
remaining
> 20 to 30 minutes. The briquettes even if exposed to an evenly applied heat
> source all around their bottom, will tend to burn from the center out, not
> uniformly and not from the outside in.
>
> Carbonisation begins in teh center and ends on the exterior surfaces.
>
(RWL): I don't understand "carbonization" - which I would reserve for
processes that leave carbon (charcoal) at the end of the cooking (which is
the case for our charcoal-making stove). I presume that there is total
combustion? Do you use this term to imply that there is a pyrolysis process
going on throughout?

Can one get a more continuous power by placing the briquettes on the
fire in a staggered fashion? Are cooks happy with the time sequencing of the
power output?

> Application of such as Approvecho's Justy or Rocket stove would retain
heat
> in the combustion chamber and allow for retention long enough to complete
> combustion. we have created similar chambers with 1 inch annular spaces .
The
> effect was to create an induced draft outside the briquette which tended
to
> augment secondary combustion above the briquette but the burn was still
most
> intense through the center core. This is only part of the story however.
> What needs to be added to either of these stoves or anyone elses for that
> matter, would be a direct feed of air from beneath the briquette and a
grate
> to let the resulting ashes (and there is s considerable production of ash,
> relative to charcoal or wood) fall off , retaining open exposure of the
> glowing red core to the cooking surface. The attached burning
demonstration up
> in the Andees a few weeks ago gives you the idea. Also attached is a
suggested
> modification of stoves to utilise the briquette in teat same region.
>
(RWL): I am suffering from still not undertanding the full operation
of your stove (so I apologize for not having read the above article). I now
gather that the intense flames do not continue throughout the burn. Better
let me read more.

Is it possible to "jiggle" the briquettes to remove the built-up ash?
and restart the moe intense power output?

> Blocking the hole reduced the heat output of the briquette to nothing much
> more than a pile of compressed leaves or if you use it sawdust or carbon
dust
> or whatever you use are a resource. It is nothing like the center core
burn
> effect, everything else being equal.
>
(RWL): Could you clarify "blocking the hole"? How is this
accomplished?

> It is our and teh technology's godafather, (Ben Bryant's) original and
> continuing intent to produce a technology so readily do-able that in the
right
> location of demand and entrepreneurial capacity, it immediately "ignites"
> interest and generates direct income amongst the poorest of the poor.
>
(RWL): Can you give any references on the work of Bryant?

> The basic starter press I detailed to Paul can be paid back in a few weeks
of
> production. In some areas we encourage the trainers NOT to sell it for
cash
> but rather set in motion the idea of producing briquettes to pay for the
> press. paybeck times are under these circumstances around 6 weeks.
> And as the entrepreneur expands and needs higher [produciton capacity, we
can
> step over to a reciprocating ram, even making it double-acting, with a
feed
> and sump tank but we have always to think carefully about who will afford
it
> and how will it be maintained. But I do not mean to imply that we are not
> holding back where the demand and capacity exists: In fact newer and far
more
> productive presses are emerging out of necessity in places like Cusco Peru
and
> probably in Kangemi Kenya and in the northern province of Haiti later this
> year.

(RWL): I have zero background in briquette presses. It sounds like you
are doing very well on this side. I am impressed by what you have done.

>
> Further into the technology still, we are considering a more
sophisticated
> application for the US household and municipality, ever more laden, as
they
> appear to be, with junk mail and yard waste but that takes money and a
serious
> investment group (if anyone is interested !)
>
(RWL): I hope others with briquetting background and support will be
contacting
you.

> A group in Cusco at their San Antonio University, is eager to design the
> perfect briquette. The problem is that it is not an issue of greater
pressure
> (the process of wet slurry dewatering is quite elastic with respect to
phase
> change. We operate ao 10 to 15 atmospheres. there is nor substantial
change in
> the density or burning quality at four times this much pressure --although
the
> capital and operating cost of the required equipment would indeed rise
> sharply.
>
(RWL): Please help me with the term "phase change". From what initial
phase to what final phase?

> Nor is the quality of the burn defined by an exact ratio of the natural
> resources we use, for these change in compostiion substantially according
to
> teh time they are harvested and teh point at which they are pulled out of
the
> decomposition cycle--- which is an essential step in preparing the
material.
> However, the method and principles used in determining the right
compostiion
> is exact. It is exact but extremely dependent upon the feel for the
material.
> Sure, the more carbonaceous the material, the greater calorific value, but
if
> the briquette is spongey or for that matter too tight, it will be less
> efficient than well prepared mixtures of your died out garden variety
grass
> clippings leaves.
>
> Thus far its been all about developing this capacity in the third world.
It is
> here where that kind of "feel" for agro residue material comes quite
> naturally. It is another story to try to train colleagues back home. That
is
> why I sometime cringe at the notion of someone simply grabbing a press and
> running off to train someone else without proper training themselves.
Quite
> frankly they would do better to go to Particia Ngari, or Nestor
Velasquez, or
> Seif Salmini, for their own knowledge of their own area, than myself.
>
(RWL): I hope they will all feel free to jump in with guidance for the
rest of us.

> Think I will have to lug one of these presses to the Biomass conference
this
> September. If we accomplish nothing else, we can all make and take home
our
> winter heating supply out of the left over papers...
>
> Happy 4th to you all
>
> Richard Stanley
> Legacy foundation
> 541 488 1559
>
>
> <snip>

(RWL) Richard - Thanks again for your responses above. I won't go over
my
questions, since there are probably answers in your written technical paper.
If not I'll be back.

I wish I had gotten my inquiry started a little earlier so as to ask a
few questions also of Paul Anderson (now presumably in the air on his way to
SA). Later. I hope he will keep us abreast of what he is doing if he can
get to a terminal.

I have made a number of other responses and questions in my three
responses to Tom Duke, Elsen Karstad, and Dr. Karve. Please jump in if
anything I said has been in error. Again congratulations on some very
interesting briquette and stove work. Sorry for not jumping in earlier.

Ron

-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/current/
http://www.ikweb.com/enuff/public_html/Stoves.html

Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net

For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From elk at wananchi.com Mon Jul 2 01:41:53 2001
From: elk at wananchi.com (elk)
Date: Tue Aug 31 21:36:57 2004
Subject: Where There's Fire......
Message-ID: <3B4008DB.00001D.14313@pentium-333>

<TD id=INCREDITEXTREGION width="100%" style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; PADDING-LEFT: 7px; PADDING-RIGHT: 7px"
>
Stovers;

Some background from Kenya......

Where
There’s Smoke There’s Charcoal……….<?xml:namespace
prefix = o ns = "urn:schemas-microsoft-com:office:office"
/>

Next
time you order your kilo of roast meat at the market, give a thought to
the fact that you about to consume half a kilo of charcoal at the same
time- or five kilos of wood from the tree’s point of view…….. 

Some figures here- they get
interesting:

Of Kenya’s 28 million inhabitants, 20% are urban
dwellers. Sixty percent of these 5.6 million urbanites use charcoal as
their domestic fuel of choice on a daily basis- more than 500 grams per
person per day. Taken at conservative rate of consumption, this amounts to
One Million, Six Hundred and Eighty Thousand kilograms of charcoal
consumed in Kenya’s cities PER DAY.

Hold on- if we take the tree’s
point of view again, how much actual wood is this? Well, the earthen-mound
kiln technique of carbonization is about the most inefficient method
available, and effectively the ONLY method currently in use in Kenya. You
get a charcoal yield from wood of between 8 and 13%- say 11% on average.
This means that on every day of the year some Fifteen Million Two Hundred
and Seventy Three Thousand kilos of tree are cut down and burned into
charcoal. 

If your average charcoal-fodder
type tree weights, say 50 kg, this amounts to one hundred and Eleven
Million Four Hundred and Ninety One trees in a year. At one thousand
trees per hectare, this amounts to eleven thousand square kilometers per
year……..

Kiln efficiency can be
increased to close to 40% with tight controls. In commercial practice just
under 30% is achievable with the use of metal or brick kilns. Sawdust can
be converted to charcoal powder at a 36% yield via the downdraft
system.


The
problem here is that there is no incentive to increase efficiency- the
wood is free for the taking. If wood was sourced from commercially planted
and nurtured woodlots it would have a commercial value prior to
carbonization- conversion efficiency would then be important. As-is, with
uncontrolled access to free material, the overriding incentive is labour,
and the earthen-mound is the simplest, easiest and most maintenance-free
method. Until the perceived value of wood as the raw material for the
manufacture of charcoal changes, there’s little hope in controlling the
impact of the charcoal industry on Kenya’s increasingly disturbed
woodlands and forests.



Elsen
Karstad
Chardust
Ltd.
<A
href="http://www.chardust.com">www.chardust.com

From elk at wananchi.com Mon Jul 2 14:08:41 2001
From: elk at wananchi.com (elk)
Date: Tue Aug 31 21:36:57 2004
Subject: Briquettes with holes
Message-ID: <3B409D14.000005.15933@pentium-333>

<TD id=INCREDITEXTREGION width="100%" style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; PADDING-LEFT: 7px; PADDING-RIGHT: 7px"
>
Ron (and Stovers);

As I'm only concerned with charcoal briquettes and am using extruders
exclusively, I can adress only a limited aspect of the 'briquettes with
holes' discussion. I think that the larger biomass briquettes do indeed
have a real need for holes- particularly those that are not
compressed/extruded under the huge pressure sufficient to melt lignin and
bind as dense (or denser) than wood.

To agglomerate a few of your questions here Ron- I could indeed
produce extruded briquettes with holes, but I think that the number of
rejects would rise tremendously. My extruders tend to warm up and
mix/agitate the charcoal powder/clay/water mixture..... which (please
excuse the description) exits the 6 inch long by 1.25 inch dia.
extrusion die with much the same consistency and temperature as dog poo.
Like dog poo, the briquettes firm up as they cool. Unlike dog poo tough,
they don't attract flies when laid out on the drying racks (thank
goodness).

Anyway- the point being, is that low pressure extruded briquettes
with holes would tend to collapse upon extrusion unless drawn out of the
machine on a conveyer. I'm sure that by increasing the pressure (using
more power) and feeding a drier mixture, some extruders would indeed
happily produce hollow briquettes.

More intense burns- and I'm sure that vertically arrayed briquettes
like Paul Hait's brilliant Pyromid inspiration are great when controlled.
The problem arises with duration. I simply do not like having to
continuously feed a charcoal fire. None of my customers want to either.
The commercial trade-off between intensity and duration tends to favour
duration when it comes to charcoal customers here in Africa. Slow is
better, as long as the minimum acceptable amount of heat is produced for
the job at hand. This would tend to be a negative factor against hollow
charcoal briquettes.

And efficiency? Well, that depends very much on the properties of the
stove, and in my experience you can cook more food on slow-burning
fuels.

As for the commercial aspects- most charcoal here in Kenya is sold by
volume. A four litre paint tin, a 20 litre vegetable tin and a feed sack
are the three most common measures. It would certainly help me to have a
hollow product- air is cheap! The novelty value of marketing a hollow
briquette could amount to a brand or trademark, and with it the
opportunity for a value-added profit. I'm not there yet though- still
struggling to compete on a price-basis with lump-charcoal made from
illegally harvested wood. Hmmm.... maybe it IS time to look for profits
though......

elk

Nairobi
www.chardust.com

From english at adan.kingston.net Mon Jul 2 18:17:48 2001
From: english at adan.kingston.net (*.English)
Date: Tue Aug 31 21:36:57 2004
Subject: Webpage update
Message-ID: <200107022215.SAA17910@adan.kingston.net>

Stovers,
You can view some new pictures, related to briquettes with holes,
from Richard Stanley. Check the "New" section.

Alex

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From reap at interlink.net Mon Jul 2 20:38:34 2001
From: reap at interlink.net (REAP-Canada)
Date: Tue Aug 31 21:36:57 2004
Subject: The energetics of corn burning
In-Reply-To: <20010629035652.17021.qmail@web13507.mail.yahoo.com>
Message-ID: <001901c10358$3b935040$0201010a@proview>

Norbert wrote:

> One item that should be added to the discussion is energy quality.
Methanol
> can be used to power cars, whereas pellets can't (very easily, anyway).
>
> Space heating requires low grade heat, so burning ethanol for space
heating
> doesn't make any sense. Neither does electricity or oil or gas, for that
> matter. ("Cutting butter with a chainsaw", as Amory Lovins said).
(snip)

I couldn't agree with Norbert more about the need for the energy quality
discussion. It just hasn't happened in a significant way.We had some
discussion on energy quality
here previously late last year (see the thread "widening the discussion
about bioenergy development").
Perhaps it would be good if we
could bring in some energy analysts like Amory Lovins and David Pimental as
speakers at a biomass conference to provoke discussion.

My feelings are that the excessive transformation of the energy quality of
biomass ... "the straw to gold" approach is the technologists dream but it
ends up being
the energy analysts nightmare..and the economics follow. Turning biomass
into a fully modern energy carrier like electricity or liquid fuel limits
its potential for economic success in the near term in most regions of the
world.

As a naive and enthusiastic student of biomass energy 10 years ago, I
invested my retirement savings in a methanol company that is now a penny
stock...today I invest in railstocks and they are doing pretty well....there
isn't enough land in the world to do it all with biomass and fossil fuels
will long hold onto the transportation market. Biomass can however make
major inroads in the energy sector by using pellets (an energy carrier of
intermediate quality) to displace high grade energy forms (like oil, natural
gas and electricity) in heat related energy applications. For example in
some hydro rich provinces in Canada up to 60% of the houses are
heated electrically. Indirectly, biomass could make major contributions to
the grid by displacing electrical heat in these applications. So there is no
need to focus on direct biomass power production when we can "produce" about
2.5 times as much electricity indirectly from the same hectare of biomass if
it is used for space heating to displace electrical space and hot water
heating.

So to paraphrase Lovins, we indeed need to match the energy quality of the
fuel with the end use application. However, there needs to be convenience
for most people,
and the fully automated fuel supply systems
that are being developed for pellet stoves and furnaces is getting close to
oil and natural gas systems for user convenience.

Roger Samson

Resource Efficient Agricultural Production (REAP)-Canada
Box 125
Maison Glenaladale
Ste Anne de Bellevue, Quebec, H9X 3V9
Tel. (514) 398-7743, Fax (514) 398-7972
REAP@interlink.net
WWW.REAP.CA

"Creating ecological systems of energy, fibre and food production"

----- Original Message -----
From: Norbert Senf <mheat@mha-net.org>
To: <stoves@crest.org>; <bioenergy@crest.org>
Sent: Friday, June 29, 2001 10:44 AM
Subject: Re: The energetics of corn burning

> At 10:03 AM 2001-06-29 -0400, REAP-Canada wrote:
> >(snip)
> >
> >I do not know if money is well spent continuing to prime the ethanol pump
> >with subsidies (or value added grants as they have been recently called)
> >when there could be major R & D efforts to develop biomass
> >heat...bioenergy's best comparative advantage for development.
> (snip)
>
> One item that should be added to the discussion is energy quality.
Methanol
> can be used to power cars, whereas pellets can't (very easily, anyway).
>
> Space heating requires low grade heat, so burning ethanol for space
heating
> doesn't make any sense. Neither does electricity or oil or gas, for that
> matter. ("Cutting butter with a chainsaw", as Amory Lovins said).
>
> One fuel that is often overlooked for space heating is cordwood. Recent
> advances in masonry heater combustion technology, for example, allow it to
> be burned on a domestic scale with particulate emissions in the same range
> as pellets, about 1 g/kg.
>
> Best ....... Norbert
> ----------------------------------------
> Norbert Senf---------- mheat@mha-net.org-nospam
> Masonry Stove Builders (remove -nospam)
> RR 5, Shawville------- www.heatkit.com
> Quebec J0X 2Y0-------- fax:-----819.647.6082
> ---------------------- voice:---819.647.5092
>
>
>
>
>
>
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> -
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>
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>

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From kdavies at igc.org Mon Jul 2 21:09:12 2001
From: kdavies at igc.org (Karl Davies)
Date: Tue Aug 31 21:36:57 2004
Subject: The energetics of corn burning
In-Reply-To: <20010629035652.17021.qmail@web13507.mail.yahoo.com>
Message-ID: <3B411AD3.F231D257@igc.org>

REAP-Canada wrote:

<snip>

> I couldn't agree with Norbert more about the need for the energy quality
> discussion. It just hasn't happened in a significant way.We had some
> discussion on energy quality
> here previously late last year (see the thread "widening the discussion
> about bioenergy development").
> Perhaps it would be good if we
> could bring in some energy analysts like Amory Lovins and David Pimental as
> speakers at a biomass conference to provoke discussion.

Sorry, but I wouldn't consider Lovins much of an energy analyst. As far as I
know, he still thinks we have 200 years of natural gas to burn. He also thinks
his Hypecar (sic) and the "New Hydrogen Economy" will save Industrial
Civilization. Fat chances.

Lovins' and Hawkens' messages play well with the "progressive" corporate types
they get paid so well to hang out with. But their messages just don't fit with
the realities of declining hydrocarbon resources and net energy analysis.
Pimentel is another story.

Karl Davies
http://www.daviesand.com
http://groups.yahoo.com/group/energyresources/messages

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From karve at wmi.co.in Mon Jul 2 22:18:13 2001
From: karve at wmi.co.in (Priyadarshini Karve)
Date: Tue Aug 31 21:36:58 2004
Subject: briquettes with holes
Message-ID: <000d01c10367$033b0940$112033ca@karve>

Stovers,
A.D. Karve (Nandu) has
already written of our experience with the char briquettes with hole(s). I just
want to add a few things.
 Firstly, he forgot to mention another disadvantage of the
honeycomb briquette - the method of production is not favourable for mass
production. The briquettes need to be made by hand, one at a time, using a mold.

Secondly, I think that our method of
stacking cylindrical briquettes vertically in a regular pattern, is somewhat
similar to (perhaps a primitive version of ) Paul Hait's Harmonic Thermal Array.
Having seen both our stack and the HTA in action, I suppose any arrangement of
the briquettes, that allows sufficient air gaps in between, should work in the
same manner.

Regarding
Ron's suggestion of lighting from the top: Please note that what Nandu and I are
talking about here are briquettes made from 'char', so there is no question of
producing charcoal while burning the briquettes.

In his first message, Ron has mentioned my
work on the sawdust stove. In this stove the sawdust is manually packed around
an L shaped cavity. Thus, in a way this is a rather big biomass briquette with a
central hole. I found that with a proper height to diameter ratio (6:1 in my
case), one gets a smokeless blue flame from the central hole. I also found that
one can introduce multiple tunnels in the packed sawdust, however this is a bit
tricky, as the sawdust is to be packed manually in the stove, and dense packing
is important to the stove operation. I have operated the stove with three
symmetrically placed L shaped tunnels (tunnel dia 4 cm), and was quite satisfied
with the result. In a way, this is like a honeycomb biomass briquette, but with
just three rather than ninteen holes.
We have also experimented with lighting
from the top in the sawdust stove. This produces a very tall and vigourous
flame, not quite suited for cooking, with the existing design of the stove (no
control over the primary air). I suppose a design similar to the Turbo
stove/charcoal making stove would be a natural end-point in the evolution of the
sawdust stove if we experiment with lighting from the top.

Regards,
Priya

Dr. Priyadarshini KarveLecturer in Physics, Sinhgad College of Engineering,
Pune, India.Member, Appropriate Rural Technology Institute, Pune,
India.Founder Member, Sandarbh, Pune, India.

Address for correspondence: 6, Koyna Apartments,
S.No.133, Kothrud, Pune 411 029, IndiaPhone:
91-020-5442217/5423258E-mail: <A
href="mailto:karve@wmi.co.in">karve@wmi.co.in / <A
href="mailto:adkarve@pn2.vsnl.net.in">adkarve@pn2.vsnl.net.in

From elk at wananchi.com Tue Jul 3 01:10:04 2001
From: elk at wananchi.com (elk)
Date: Tue Aug 31 21:36:58 2004
Subject: Snapshot from Nairobi: Energy costs
Message-ID: <3B4152D5.000010.17395@pentium-333>

<TD id=INCREDITEXTREGION style="FONT-FAMILY: Comic Sans MS; FONT-SIZE: 10pt; PADDING-LEFT: 7px; PADDING-RIGHT: 7px"
width="100%">
Stovers;

It is said that you can double the cost of cooking at each point
between the following fuels:

wood >> charcoal >> kerosene & LPG >>
electricity

This point is driven home with an analysis of the comparative costs
between heating water with charcoal and electricity:

I've recently started marketing a simple upright 90 litre cap'y
charcoal-fired water heater here. It's pictured in the Stoves website-
using five vertical 1" dia. pipes as chinmeys running through a tall
cylindrical water tank. The firbox is in the base.

We've tested this out at close to 50% efficient, which is pretty
good, and I understand that by comparison, immersion water heaters are
running at close to 75%. Please correct me if I'm wrong here or if any of
the following analysis is flawed:

In Kenya we pay as much as US $ 0.14 per kilowatt-hour for
electricity. My observation is that it takes a minimum of 2 hours for a 3
kW electric immersion heater to raise 90 litres of water 50 ' C. This
is effected at a cost of (.14*3)*2= US $ 0.84.

My charcoal heater does the same amount of work in roughly the same
amount of time with 2.5 kg of my briquetted vendor's waste charcoal
at cost of usd $ 0.17

This does underscore why lower income groups here in Kenya aren't
connected to the National grid, doesn't it? The wide disparity in energy
costs here is also highlighted, and just maybe the energy from biomass is
undervalued? Is this gap quite as large in developed countries
too?

elk
Nairobi
www.chardust.com

_________________________________________________IncrediMail - Email has finally
evolved - Click "
Url : http://listserv.repp.org/pipermail/stoves/attachments/20010702/41176881/bin00223.bin
From heat-win at cwcom.net Tue Jul 3 01:58:51 2001
From: heat-win at cwcom.net (Thomas J Stubbing)
Date: Tue Aug 31 21:36:58 2004
Subject: [Fwd: [energyresources] Sustainability plans]
Message-ID: <3B415DBA.FA47982E@cwcom.net>

Dear All,

Opinions vary as to when first oil, then natural gas and fnally coal
will run out but certainly we cannot go on burning four times as much
oil as is being discovered for ever! In that and the broader context
outlined in this forwarded message (sent to the 'gasification' but not
to the 'stoves' list) we are going to need stoves as never before.

I hope you find it interesting.

Regards,

Thomas J Stubbing

To: "energyresources" <energyresources@yahoogroups.com>
Subject: [energyresources] Sustainability plans
From: "Kermit Schlansker" <kssustain@provide.net>
Date: Mon, 2 Jul 2001 11:41:03 -0400
Cc: "solar conc." <solar-concentrator@cichlid.com>, "Sustainable Community" <sustainablecommunity@egroups.com>, "Gasification" <gasification@crest.org>, "Malletts Creek Group" <malletts@umich.edu>, "smartgrowth" <smartgrowth-washtenaw@great-lakes.net>, "ROE" <RunningOnEmpty@yahoogroups.com>
Delivered-To: mailing list energyresources@yahoogroups.com
List-Unsubscribe: <mailto:energyresources-unsubscribe@yahoogroups.com>
Mailing-List: list energyresources@yahoogroups.com; contact energyresources-owner@yahoogroups.com
Reply-To: energyresources@yahoogroups.com

I wish all of you on ROE, and energyresources would stop bickering, stay on
subject, and concentrate on work that will help save my Grandchildren. A
book which is very much on subject which I hope some of you will buy is
"Renewable Energy" from Island press This book gives a good survey of
solar, wind, and biomass. As it
stands now there are no tactics published on the Internet that will save
society. The various energy groups are really not combining to produce a
sustainability plan. I have tried but my material needs improvement and no one
reads it. We need to
figure out some tactics which will make a difference. We could possibly write a
manifesto and try to get some of our lawmakers to read it. Certainly it is
possible to prevent wholesale death in the USA for 200 years if the right things
are done.
The keys to
Sustainability are apartment houses, planned communities, railroads, co
manufacturing, cogeneration, everyone farming and manufacturing, no houses, no
cars, no planes, technically adroit conservation, massive tree planting, solar,
wind, and biomass energy and short travel distances.
I am
including my latest 4 minute speech to Ann Arbor City Council.


Kermit Schlansker Ann Arbor,
Mi

Biomass

When
natural gas and oil are gone there will be insufficient coal, solar, or wind to
heat houses. It will take martial law to prevent the wholesale cutting of trees.
Solar and wind are regional and intermittent sources and can never replace
fossil fuels in the quantity that we are using now. Possible biomass energy
sources are wood, crop residues, energy crops, leaves, grasses, seaweed, algae,
sewage, and manure. A mass planting of trees would not only store carbon thus
slowing Global Warming, but would also make an energy source for future
generations. Trees grow food in the form of fruit and nuts. Forests are useful
for nature, lumber, fuel, food and topsoil. Leaves and cuttings from trees and
shrubs are an excellent source of energy. Ashes from burning biomass will become
a prime source of fertilizer in the future. Biomass is the only energy source
that is dependable enough to heat buildings in the winter. However unless it is
used in the most efficient way there will not be enough.
The most popular way of using
wood to make electricity has been to convert it to steam in a boiler and then
use the steam to power steam engines or turbines. Another process is to
partially burn wood chips thus producing a combustible gas that can be used to
run an engine. During World War 2 the Germans and many others powered cars with
wood chips. I myself crouched beside the gasification stove while riding with a
German salesman shortly after the war in the back of a wood powered VW bug.
There is a design of a small wood gas generator on the Internet that powers a
tractor. If the wood gas is ran through a catalyst it is possible to make
methanol. This probably will be the prime method of making tractor fuel because
it can be done anywhere in the country on a local basis and uses cellulose
rather than food as
feedstock. A way of
converting soft biomass to energy is to combine it with sewage in a tank and use
the digesting action of bacteria to produce biogas that is a mixture of methane
and carbon dioxide. The process is about 50% efficient. The really good thing
about this process is that tank residues are excellent fertilizers. This gas can
also be converted to methanol. In China there are many small biogas generators
made from polyethylene bags. Every scrap of human and animal manure is carefully
saved for these bags. Much of this energy is used for
cooking. Ethanol is a
possible tractor fuel and can be made from corn or other sources of starches and
sugars. This process has been controversial because food is used as feedstock
and because it takes about as much energy to produce the ethanol as there is in
it. Production of
Ethanol and Methanol and other biomass processes can be made more energy
effective if they are done only in the winter by heating systems. In that way
all of the waste heat from digestion, fermenting, distilling, chemical processes
and electrical generation is used to heat the building and the process becomes
100% efficient. Another efficient way of gasifying wood and distilling ethanol
would be to do it in summer using solar mirrors and collecting the waste heat to
make
electricity.
Local governments must get involved in planting fruit and nut trees for food and
energy and do research on how to plant at lowest cost. Future generations can
not exist if local governments persist in being so technically inept and morally
uncaring in their attitude towards the future.


Kermit Schlansker

Your message didn't show up on the list? Complaints or compliments?
Drop me (Tom Robertson) a note at t1r@bellatlantic.net

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

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From rstanley at legacyfound.org Tue Jul 3 04:16:14 2001
From: rstanley at legacyfound.org (Richard Stanley)
Date: Tue Aug 31 21:36:58 2004
Subject: Briquettes with holes - (R. Stanley)
In-Reply-To: <4.3.1.2.20010629093006.00e15930@mail.ilstu.edu>
Message-ID: <3B417EDC.FE71D02E@legacyfound.org>

> Ron et al,

Following your comments to my replies about the holy briquette issue:
The article is no longer posted on the web (the journal of chemical innovaiton
pulls it off the site, after a few months, by policy. It was the front article
in the February issue of Chemical Innovation of the ACS, titled" A Unique
Approach to Conservation pp 22 - 28.

Perhaps I am using the incorrect term when using the word, " carbonisation".
What I am referring to is a blackening of the material from the center hole
outward. If the burn is interrupted once the surface is blackened, or
carbonised (smothering the briquette to prevent further combustion) the
briquette will behave very much like charcoal in a subsequent burn. Indeed
only in passing through this state with the licking flames etc., it begins to
behave like charcoal with a radient red glowing core.

There is complete combustion in that all that remains is a completely whitened,
friable ash- at the end of the process but it would appear that in the process
we are making a form of ?or passing through a stage of?charcoal making with
incomplete combustion, in getting to that final completely combusted state.

It is agreed however that this is hardly a charcoal production exercise, as the
attempt is to create an oxygen rich environment, not a reducing environment.
In as much as we start with partially decomposed compressed agro residues, and
move through what appears to be a carbonised solid into a burning radient core
before arriving at complete ash material, it is changing state. I could not
honestly state whether this answers your question about a pyrolysis process
going on throughout.

How the cooks handle the burning rate...

Most often the cooks like to simply jam them into a clay stove (see the recent
Peru photos on Alex's site ) or atop a grate with little regard to alignment,
other than the fact that they will try to keep them upright. The latter is
usually enough to assure them of fairly good performance. The rapid rist is
great for cooking quick meals . but that temperature curve will depend upon the
ingredients used. In Malawi we used the water hyacinth and or the coarse
(starchy residues from corn milling to slow down and extend the burn, much as
clay is used in the charcoal briquettes (aside from its other advantage as a
binder ).

One can jiggle the briquettes or simply add more to maintina a more constant
heat output but the tendency is to design the briquette burn characteristic
into the mixture. You buy the mixture you want for your cooking and heating
needs. Like pine versus Oak or hickory smoked versus mesquite flavored. its
hyacinth vesus mango or cedar shavings versus eucalyptus , or corn stover and
harina versus eucalyptus and potato stems .
Kind of fun to see what emerges. It is different in every area and it is
designed by the producers acting in response to their own cultural epicure in
balance with their own resources and indiginous botannical knowledge. Generally
there is the flame up period for accompanied by a darkening of the surface
then a die back into the coal stage .

One can of coure jiggle the briquettes to remove the ash and this is usually
done. The trick with teh briquetes, is to assure that the jiggled briquette
sheds its ash well beneath the embers in such a manner as to not block the air
flow from beneath. This is accomplished through the use of a relatively coarse
1.5" to 2 " square grate or the equivalent, set about 2 inches above the floor
of the stove. One could make the grate coarser such that the ember itself will
fall down after a few minutes into that stage of the burn. This allows
maintenance of the flame stage by simply adding new briquettes atop the embers
a the right time. Because the ember stage is effectively generating radient
heat ,it requires /is very sensitive to distance from the cooking surface. If
it were easy to effect a rising grate which one would operate with a
counterweight such that as the briquette mass was reduced, the grate would lift
it closer to the pot , this would be the ideal. Accomplishing such.a feat
reliably and economically in a development environment is another story.

The usual practice is to simply toss in a few more briquettes and or to adjust
the recipe to the heating or cooking application. At their average cost of 2.5
us cents and 2 to 4 per person per day consumption rate (measured over the six
nations we have extended the technology over the past seven years from sea
level to 11,500 ft) we usually can equal or beat the price of wood and
charcoal, so such niceties are a counterbalanced rising grate are not exactly
critical to the adaptation process.

By blocking the hole I should have more accurately stated that we simply do not
create a hole by removing the center pipe from the mold, making a solid
cylindrical briquette.

As concerns Ben Bryant's publications, I would kindly refer you to Dr. Ben
Bryant's email address: fibro@uswest.net
As former professor emertitus of the College of Forest Resources at University
of Washington, I am sure he could provide you with a list of publications on
the subject. My first contact with Ben began in the late 1970's where I had
read about his work in a Volunteers in Technical Assistance publication whilst
manageing a 7 yr long Appropriate technology project in Arusha Tanzania. four
nations and five assignments later I had subsequent reason to apply his ideas
in Malawi while residing there from 1994 through 1999.

I maintain a working relationship with Ben to date through ongoing project
extension and design work. with his life long immersion teaching and research
in natural materials , he is a well respected technical advisor on our
foundation's board.

With respect to Phase changes :
We begin with a slurry of between 15 and 25 % fibrous solids and pith (and in
the case of sawdust or rice husks, granular material) in water. the press
dewaters this mass. Assuming the right permeability , combined with the right
elasticity /plasticity the mass is dewatered, randomly aligned and interlocked
fibers, to result in a damp mass which will then be reduced under simple open
air drying conditions in four to six days to about 1/3rd its "press-exit"
weight. The mixture is obviously a liquid but once dewatered behaves as a
solid--al at ambient temperature with this method. This process incorporates a
compound lever press which has a practical operating pressure of about 2000 lbs
+/-500 depending on operator strength. Tests under hydraulic rams with 5 times
this pressure do nto significantly change the nature or strength _OR DENSITY of
the final product. In fact not until one increases pressure ten times or more
does one begin to see evidence of a pahse change from solid cake dewatering to
resin release and literal flow of resinous materials. This is what I call a
phase change form solid to plastic if nto liquid. The latter process might make
sense in an urban dense population area, and it implies such an increase in
cost and other production factors temperature control, precision in the ram
tolerances, maintanance, training, etc, that it does not make sense where the
objective is to generate employment amongst microentrepreneurs.

As to whether Seif or Patricia, Nestor or the dozens of tohers would feel like
jumping in to support your curiosity , you might have to first establishwhat we
are taking for granted in this news group: Ie., that we are acting out of
goodwill and in the interest of improving the science of the process for the
common good. I am assuming this is what Paul Anderson in Mozambique is now
attempting with a local and indigenous population, although he is riding only
on a few emails to guide him in the effort.
Patricia Ngari runs the Kangemi women empowerement center, in Kangemi, just
outside Nairobi (I'm sure Elf knows her) . Nestor Velasquez is the project site
manager in Cusco Peru, Seif is or was a site manager in Mangochi district,
Malawi.

As to Els' experience in Niarobi, I do not recall him when I began in East
Africa in 1974. I have see nhis briquettes and he has a very good product. His
market is for the urban areas and is being developed as a bursiness by him
which is commendabel in nairobi these days. Our two project s in Kenya
Kangemi(above) and prior to that in Makueni are of a different focus. We are
trying to generate income while providing a rpoduct which competes with
fuelwood and charcoal. It cannot be as hot as charcoal as it has far to little
carbon.(In Bamaco Mali, where carbon dust is abundant and the briquettes were
made of up to 45% charcoal dust, the resulting briquettes were in fact far
superior to charcoal but that was urban Bamaco, not rural Kenya, where the
sites were distant from the 'fines' as byproducts of charcoal production). It
can however compete well with most kinds of fuelwood in use in these sites and
that is why we sought them out.

Well family is coming in for the fourth of July here, so have got to fire up
grille (If you've ever tasted a chicken leg roasted over briquettes made of
cedar fronds and junk mail, You will never go back to mesquite !)

Anon,

Richard Stanley

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Stoves List Archives and Website:
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From kchishol at fox.nstn.ca Tue Jul 3 13:08:41 2001
From: kchishol at fox.nstn.ca (Kevin Chisholm)
Date: Tue Aug 31 21:36:58 2004
Subject: [Fwd: [energyresources] Sustainability plans]
In-Reply-To: <3B415DBA.FA47982E@cwcom.net>
Message-ID: <NEBBLHHHOLFOEGCILKHEGEANCOAA.kchishol@fox.nstn.ca>

Dear Thomas

...del....

> Dear All,
>
> Opinions vary as to when first oil, then natural gas and fnally coal
> will run out

You assume that we will run out of oil, gas, and coal. We will NEVER run out
of gas, oil and coal, and that is not an opinion; that is an absolute fact.

What will happen is that as these resources get scarcer, their prices
increase, and then it becomes worthwhile conserving.

but certainly we cannot go on burning four times as much
> oil as is being discovered for ever!

Of course not. What you are doing is makint the same mistake that the Club
of Rome did: linear assumptions that don't recognize non-linear changes in
demand as a result of increase in prices.

In that and the broader context
> outlined in this forwarded message (sent to the 'gasification' but not
> to the 'stoves' list) we are going to need stoves as never before.
>
> I hope you find it interesting.

The posting is excessively philosophical, and the well meaning gentleman has
fixed views that are not open to discussion. The Bioenergy List was occupied
with such discussions, and they seem to have accomplished very little.

Is it possible to stick closer to the design, construction, and testing of
stove systems, and to reserve philosophical discussions about the World's
Energy Problems for other venues?

Kevin Chisholm
>

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Stoves List Archives and Website:
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From adkarve at pn2.vsnl.net.in Tue Jul 3 20:40:27 2001
From: adkarve at pn2.vsnl.net.in (A.D. Karve)
Date: Tue Aug 31 21:36:58 2004
Subject: Briquettes with holes
In-Reply-To: <000301c1029b$b47f1ba0$5c7de13f@computer>
Message-ID: <000001c10424$19b96a00$5d8ac7cb@vsnl.net.in>

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BioEnergy Lists: Improved Biomass Cooking Stoves

July 2001 Biomass Cooking Stoves Archive