November 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 ronallarson at qwest.net Thu Nov 1 01:31:48 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:15 2004
Subject: Refractories and Insulation
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <004201c1629f$20eb53e0$03e26641@computer>

Stovers:
I believe Peter would not mind my sending this reply on to the full
list - and perhaps it was his intent to send his message to stoves as well.

----- Original Message -----
From: Peter Verhaart <pverhaart@optusnet.com.au>
To: Ron Larson <ronallarson@qwest.net>
Sent: Wednesday, October 31, 2001 10:49 PM
Subject: Re: Refractories and Insulation

> At 07:34 31/10/01 -0700, you wrote:
> >Harmon and stovers:
> >
> >
> > (RWL):
>
> Snip
>
> > The cost was $4.00 per square foot (about $4
> >per square meter).
> Wouldn't that be $36/m2 ?
>
(RWL) I accept that my approximation was a little loose - but I believe
after reflection that you will agree the swing is the other way - to
$43.06/m2. (1 sqft = .0929034 m2). Maybe some day (next century?) the US
will start pricng goods in m2 and this problem will go away.

>
> > An example in addition to the ones Tom Reed recently mentioned is the
> > Bunsen Burner. This works because
> >the (laboratory) gas is under pressure so that a Venturi effect can draw
in
> >the correct (controllable) amount of total air (no need to separate into
> >primary and secondary when the gas is totally combustable). Then mixing
> >occurs over a height of many diameters (6-10?) in what I remember, and
the
> >flame is a lovely blue color that we all want. I hope someone can tell
of
> >experiments or theory that says what that minimum height has to be for
the
> >laboratory-type Bunsen burner - that will help get at the question you
are
> >asking. I think Alex English may have studied this some.
>
> >
> When we had so-called Town gas (from coal, containing much H2), which has
> an appreciable blow-off velocity (the gas velocity at which the flame
blows
> off the nozzle), the diameter of the chimney is such that the flame will
> not be able to travel downward at the lowest setting.
> With Natural or LP gas, the flame velocity is much lower. In burners for
> these gases we find close to the nozzle a flow obstacle which offers an
> abrubt widening of the diameter, leaving a dead-water region with low
> circulation right after the obstacle where the burning gas-air mixture can
> burn while constantly reigniting the main flow. This is probably the cause
> of the noise ghese flemes make.
>
(RWL): Hmm. 1) I had not realized these attributes - but you have
whetted my appetitie on learning more. Any good references on velocities
and the reasons for widening and the noise associated. Any contribution on
the height needed for mixing?

>
> > In the Bunsen burner, that point is where one has a "screen". There
is
> >something about flame propagation speed that dictates how small the
screen
> >pores must be to not have the flame propagate down the "Bunsen burner"
> >mixing tube.
>
> It is more to prevent the blowing off, I think.
>
(RWL): We are way out of my element here. I guess you are saying that
the problem is not so much with flame fronts traveling back towards the
source. Again, I'd appreciate some references.

> >Because catalysis is important in flame ignition
> >temperature, we should be asking something about materials as well -
maybe
> >even a sacrificial material (if low cost).
>
> Dennis Jaasma has done tests with a catalyst (from Dow-Corning if memory
> serves) in the early eighties at Virginia State University.
>
(RWL) : Anyone able to add to this lead? Afraid I don't remember seeing
his name before - but "Jaasma" sounds like a possible graduate from
Eindhoven?

Piet - thanks for the added information. Ron

> Piet
>
>

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From Carefreeland at aol.com Thu Nov 1 05:50:18 2001
From: Carefreeland at aol.com (Carefreeland@aol.com)
Date: Tue Aug 31 21:37:15 2004
Subject: Refractories and Insulation
Message-ID: <14f.35507bc.291282d8@aol.com>

Tom R.
About those riser sleves. Is the "rigidisor" sodium silicate? I have a
buddie who casts Aluminum, and uses sodium silicate solution for a binder in
his sandmolds. He uses CO2 gas from a dry ice "melter" to cure the molds.
(we know that dry Ice sublimes directly into CO2 gas, no liquid phase). I
know that sodium silicate is used extensively in fireproofing and is a good
thing to work with while experimenting on combustion.
Dan Dimiduk

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From mheat at mha-net.org Thu Nov 1 07:41:21 2001
From: mheat at mha-net.org (Norbert Senf)
Date: Tue Aug 31 21:37:15 2004
Subject: Refractories and Insulation
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <4.3.2.7.2.20011101073033.00c4f2e0@127.0.0.1>

At 11:33 PM 2001-10-31 -0700, Ron Larson wrote:
>(snip)
> > Dennis Jaasma has done tests with a catalyst (from Dow-Corning if memory
> > serves) in the early eighties at Virginia State University.
> >
> (RWL) : Anyone able to add to this lead? Afraid I don't remember seeing
>his name before - but "Jaasma" sounds like a possible graduate from
>Eindhoven?

Dr. Jaasma is at the Dep't of Mechanical Engineering at Virginia
Polytechnical Institute in Blacksburg. He used to run the combustion lab
there, and now has a private consulting company. He has done a lot of
research on wood burning heating stoves. The first North American masonry
heater testing was done at his lab in 1989, when we needed to develop a
protocol for emissions testing.

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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From mheat at mha-net.org Thu Nov 1 07:42:53 2001
From: mheat at mha-net.org (Norbert Senf)
Date: Tue Aug 31 21:37:15 2004
Subject: Refractories and Insulation
In-Reply-To: <14f.35507bc.291282d8@aol.com>
Message-ID: <4.3.2.7.2.20011101074127.00bf6f00@127.0.0.1>

At 05:50 AM 2001-11-01 -0500, Carefreeland@aol.com wrote:
> Tom R.
> About those riser sleves. Is the "rigidisor" sodium silicate? (snip)

I once bought a bucket of rigidizer from A.P. Green, and it was zirconium.

Best .... Norbert

-
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From tombreed at home.com Fri Nov 2 07:33:59 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:15 2004
Subject: GAS-L: Power Point of Shimada
Message-ID: <005001c16396$c5d995e0$18e5b618@lakwod3.co.home.com>

Dear John Olson:

Loved your site <A
href="http://sites.netscape.net/hempcree/creeindustries">http://sites.netscape.net/hempcree/creeindustriesand will
recommend it to various clients of mine. Yes, please send me a copy of your
power point presentation.

Do you know Hub Stassen in the Netherlands? I believe he
has several Shimada plants operating.

~~~~~~~~
Here are two questions for an experienced
densifier.

1) You quote 45 kW for 500 kg/hr as the power
requirement for wood. 100 kWh/ton seems to be fundamental
requirement in pelletizing, cubing and loging. This is because the solid
structure of wood requires this to break it down.

However, there are many things which are already "broken
down". In particular, I am thinking of sugar cane bagasse which has
already been crushed. Would you expect such a material to require
significantly less power?

2) Do you have comparative power requirement figures for

Pelletizing (1/4 in to 3/4 in)
Cubing (1 in to 1/5 in ?)
Logging and Hockey pucks ( 2in to 4 in?)

I see a great demand for all three types of densification as
the costs of fossil fuels rise. But power consumption will also rise, so
this is not a trivial question.

Yours truly,
TOM
REED

BEF

Dr. Thomas
Reed The Biomass Energy Foundation 1810 Smith Rd., Golden, CO
80401303 278 0558; <A
href="mailto:tombreed@home.com">tombreed@home.com; <A
href="http://www.woodgas.com">www.woodgas.com

BEGIN:VCARD
VERSION:2.1
N:Reed;Thomas;B;Dr.
FN:Thomas B Reed
NICKNAME:Tom
ORG:Biomass Energy Foundation;Publication, Consulting, Engineering
TITLE:President
TEL;WORK;VOICE:303 278 0558
TEL;HOME;VOICE:303 278 0558
TEL;CELL;VOICE:303 913 2074
TEL;WORK;FAX:303 278 0558
TEL;HOME;FAX:303 278 0558
ADR;WORK:;;1810 Smith Rd.;Golden;CO;80401;USA
LABEL;WORK;ENCODING=QUOTED-PRINTABLE:1810 Smith Rd.=0D=0AGolden, CO 80401=0D=0AUSA
ADR;HOME;ENCODING=QUOTED-PRINTABLE:;;1810 Smith Rd=0D=0A=0D=0A;Golden;CO;80401;United States
LABEL;HOME;ENCODING=QUOTED-PRINTABLE:1810 Smith Rd=0D=0A=0D=0A=0D=0AGolden, CO 80401=0D=0AUnited States
X-WAB-GENDER:2
URL;HOME:http://www.woodgas.com
URL;WORK:http://www.woodgas.com
BDAY:20010315
EMAIL;PREF;INTERNET:tombreed@home.com
REV:20011102T120615Z
END:VCARD

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From tombreed at home.com Fri Nov 2 08:24:30 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:15 2004
Subject: GAS-L: Riser Sleeve Rigidizing
Message-ID: <009201c1639d$bfd04fc0$18e5b618@lakwod3.co.home.com>

Dear All:

Riser sleeves (from foundries) are great for high temperature insulation,
but get very soft after heating >800 C. To avoid this, use "rigidizer".

Norb Senf and Dan Dimiduk asked ...
>
> No, the "rigigidizer" is colloidal silica (made from sodium silicate with
> the sodium washed out). Solid water glass (sodium silicate) has a very
low
> melting point, while silica is over 1500 C.
>
> The stuff is very expensive in small quantities, but should be inherently
> cheap.
>
> Yours, TOM REED
>
>
> ----- Original Message -----
> From: "Norbert Senf" <mheat@mha-net.org>
> To: <Carefreeland@aol.com>; <tombreed@home.com>; <stoves@crest.org>
> Sent: Thursday, November 01, 2001 5:42 AM
> Subject: Re: Refractories and Insulation
>
>
> > At 05:50 AM 2001-11-01 -0500, Carefreeland@aol.com wrote:
> > > Tom R.
> > > About those riser sleves. Is the "rigidisor" sodium silicate?
> (snip)
> >
> > I once bought a bucket of rigidizer from A.P. Green, and it was
zirconium.
> >
> > 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
> >
> >
> >
> >
> >
> >
> > -
> > Stoves List Archives and Website:
> > http://www.crest.org/discussion/stoves/current/
> > http://www.ikweb.com/enuff/public_html/Stoves.html
> >
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> > Ron Larson, ronallarson@qwest.net
> > Alex English, english@adan.kingston.net
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> >
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> >
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> > -
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> > http://solstice.crest.org/renewables/biomass-info/carbon.shtml
> >
> > For information about CHAMBERS STOVES
> > http://www.ikweb.com/enuff/public_html/Chamber.htm
> >
>

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From tombreed at home.com Fri Nov 2 08:49:19 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:15 2004
Subject: Gas combustion principles...
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <00a201c163a1$2e0be320$18e5b618@lakwod3.co.home.com>

Dear Ron, Piet and All Biomass Enthusiasts:

We are cursed with using solid fuels of widely varying properties (density,
moisture content, shape, size, ...) which makes it difficult to generalize
about burning biomass. And if you succeed, all you get is heat! (Sure,
steam, power at low efficiency).

Fortunately, from all this biomass you can make (with air) "producer gas" or
"synthesis gas" (with oxygen) which is much easier to burn for heat, power
or chemical synthesis.

Producer gas from wood and biomass ("WoodGas") is much like the producer
gas, town gas, ... that our grandparents all used in their cook stoves and
lighting. The combustion of gas has been WELL UNDERSTOOD since 1900. Your
gas stove, propane camp stove, furnace, .... all work fine. If you don't
understand how gas burns, read on.

Peter's remarks on the Bunsen Burner are right on. I believe the mixing
distance of a "free jet" (of gas into aspirated air) is 5-10 diameters (of
the jet) and in the Bunsen burner the jet is typically < 1mm, so the 12 cm X
1 cm diameter tube gives plenty of room for mixing.

An even more interesting device is the Meeker burner. The flame is about 3
cm in diameter and composed of ~100 flamelets. By adjusting the air/fuel
ratio it can be made to burn from

very rich (tail flame primarily hot CO and H2)

to stoichiometric (CO2 and H2O only at ~2000 C)

to very lean (tail flame not so hot CO2 and H2O and O2)

By tinkering with the needle valve and gas pressure and air supply it can
be made to burn in the

normal cone
inverted cone
radiant burner mode (below the holes on the flashback screen)

I have one that I run on a propane cylinder on my dining room table right
now! I have published several papers on pyrolysis of wood in the flame.

I recommend buying both types of burners (Fisher Scientific) for your
self-edification in gas burning if you have any interest in WoodGas.

Yours truly, TOM REED BEF

tombreed@home.com; www.woodgas.com
----- Original Message -----
From: "Ron Larson" <ronallarson@qwest.net>
To: "Peter Verhaart" <pverhaart@optusnet.com.au>; <stoves@crest.org>
Sent: Wednesday, October 31, 2001 11:33 PM
Subject: Re: Refractories and Insulation

> Stovers:
> I believe Peter would not mind my sending this reply on to the full
> list - and perhaps it was his intent to send his message to stoves as
well.
>
> ----- Original Message -----
> From: Peter Verhaart <pverhaart@optusnet.com.au>
> To: Ron Larson <ronallarson@qwest.net>
> Sent: Wednesday, October 31, 2001 10:49 PM
> Subject: Re: Refractories and Insulation
>
>
> > At 07:34 31/10/01 -0700, you wrote:
> > >Harmon and stovers:
> > >
> > >
> > > (RWL):
> >
> > Snip
> >
> > > The cost was $4.00 per square foot (about $4
> > >per square meter).
> > Wouldn't that be $36/m2 ?
> >
> (RWL) I accept that my approximation was a little loose - but I
believe
> after reflection that you will agree the swing is the other way - to
> $43.06/m2. (1 sqft = .0929034 m2). Maybe some day (next century?) the US
> will start pricng goods in m2 and this problem will go away.
>
>
> >
> > > An example in addition to the ones Tom Reed recently mentioned is the
> > > Bunsen Burner. This works because
> > >the (laboratory) gas is under pressure so that a Venturi effect can
draw
> in
> > >the correct (controllable) amount of total air (no need to separate
into
> > >primary and secondary when the gas is totally combustable). Then
mixing
> > >occurs over a height of many diameters (6-10?) in what I remember, and
> the
> > >flame is a lovely blue color that we all want. I hope someone can tell
> of
> > >experiments or theory that says what that minimum height has to be for
> the
> > >laboratory-type Bunsen burner - that will help get at the question you
> are
> > >asking. I think Alex English may have studied this some.
> >
> > >
> > When we had so-called Town gas (from coal, containing much H2), which
has
> > an appreciable blow-off velocity (the gas velocity at which the flame
> blows
> > off the nozzle), the diameter of the chimney is such that the flame will
> > not be able to travel downward at the lowest setting.
> > With Natural or LP gas, the flame velocity is much lower. In burners for
> > these gases we find close to the nozzle a flow obstacle which offers an
> > abrubt widening of the diameter, leaving a dead-water region with low
> > circulation right after the obstacle where the burning gas-air mixture
can
> > burn while constantly reigniting the main flow. This is probably the
cause
> > of the noise ghese flemes make.
> >
> (RWL): Hmm. 1) I had not realized these attributes - but you have
> whetted my appetitie on learning more. Any good references on velocities
> and the reasons for widening and the noise associated. Any contribution
on
> the height needed for mixing?
>
> >
> > > In the Bunsen burner, that point is where one has a "screen".
There
> is
> > >something about flame propagation speed that dictates how small the
> screen
> > >pores must be to not have the flame propagate down the "Bunsen burner"
> > >mixing tube.
> >
> > It is more to prevent the blowing off, I think.
> >
> (RWL): We are way out of my element here. I guess you are saying
that
> the problem is not so much with flame fronts traveling back towards the
> source. Again, I'd appreciate some references.
>
> > >Because catalysis is important in flame ignition
> > >temperature, we should be asking something about materials as well -
> maybe
> > >even a sacrificial material (if low cost).
> >
> > Dennis Jaasma has done tests with a catalyst (from Dow-Corning if memory
> > serves) in the early eighties at Virginia State University.
> >
> (RWL) : Anyone able to add to this lead? Afraid I don't remember
seeing
> his name before - but "Jaasma" sounds like a possible graduate from
> Eindhoven?
>
> Piet - thanks for the added information. Ron
>
> > Piet
> >
> >
>
>
> -
> 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
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
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>
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> -
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> http://www.fsec.ucf.edu/bioam/
> http://solstice.crest.org/renewables/biomass-info/
> http://solstice.crest.org/renewables/biomass-info/carbon.shtml
>
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm
>

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From tombreed at home.com Sat Nov 3 10:23:05 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:15 2004
Subject: GAS-L: More on Bynsen, Meeker burners...
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <01b601c16475$8970b220$18e5b618@lakwod3.co.home.com>

Dear Andrew and All:

I forgot to mention that the Meeker burner has a nice stamped metal Venturi
mixing section you might like to study and copy.

Andrew said..

I think there is an element of diffusion in a bunsen burner flame
also, the hottest part, the bright blue, is premixed, the outer darker
blue is the diffusion flame. If I remember this correctly then the gas
flame is a two stage process. This is also demonstrated in an
oxy-acetylene burner where you control the fuel:air mix by maximising
the contrast between these zones.

Yes, there is an outer diffusion flame IF THE MIXTURE IS RICH. However, a
lean mixture will burn completely in the primary cone (about 0.1 mm thick).
The stoichiometric flame (correct oxygen) gives the highest temperature and
heat transfer.

The oxy-acetylene flame is one of the most interesting. Acetylene has a
very high positive heat of formation - 54 kcal/mole - and so can explode
spontaneously without access to oxygen according to...

C2H2 ==> 2 C (soot) + H2

The hottest flame is

C2H2 + O2 ==> 2 CO + H2 (+ 1/3 of it atomic H)

Since CO is an incredibly stable molecule (9ev dissociation) this flame has
a temperature of 3110C the highest common flame temperature.

The complete heat release occurs when

C2H2 + 5/2 O2 ==> 2 CO2 + H2O

This was all well known at the turn of the century and oxy-acetylene welding
was king until electric arc welding took over.

Your fire-freak...... TOM REED
Dr. Thomas Reed
The Biomass Energy Foundation
1810 Smith Rd., Golden, CO 80401
303 278 0558;
tombreed@home.com; www.woodgas.com
----- Original Message -----
From: "AJH" <andrew.heggie@dtn.ntl.com>
To: <stoves@crest.org>
Sent: Wednesday, October 31, 2001 9:46 AM
Subject: Re: Refractories and Insulation

On Wed, 31 Oct 2001 07:34:12 -0700, "Ron Larson"
<ronallarson@qwest.net> wrote:

>
>
> Now if one wishes, one can concentrate on premixing the air - and this
>is the approach of Tom Reed and some others. An example in addition to the
>ones Tom Reed recently mentioned is the Bunsen Burner. This works because
>the (laboratory) gas is under pressure so that a Venturi effect can draw in
>the correct (controllable) amount of total air (no need to separate into
>primary and secondary when the gas is totally combustable).

I think the bunsen burner is an eductor or aspirator rather than a
venturi, it is a kinetic energy driven device rather than a velocity
change creating "lift".

> Then mixing
>occurs over a height of many diameters (6-10?) in what I remember, and the
>flame is a lovely blue color that we all want.

> I hope someone can tell of
>experiments or theory that says what that minimum height has to be for the
>laboratory-type Bunsen burner - that will help get at the question you are
>asking. I think Alex English may have studied this some. A lot must have
>to do also with the turbulence that one can achieve when the air and gas
>first start mixing and the angle at which the two flows meet and progress
up
>to the point wher the flame begins.

This height is presumably to allow mixing, it could be of any length
but then more prone to blowback, the thing that attaches the flame to
the top of the burner is to do with the velocity of the pre-mixed
products and the flame speed of the mixture.
>
> In the Bunsen burner, that point is where one has a "screen". There is
>something about flame propagation speed that dictates how small the screen
>pores must be to not have the flame propagate down the "Bunsen burner"
>mixing tube. I hope someone on the list can point us to that literature -
>it could help answer something about mixing. (The reason for thinking all
>this through well is that we want to keep the excess air down so as to keep
>the temperatures and therefore the efficiency high.)

I do not recall these screens, are you perhaps referring to the gauze
experiment where it can be shown the gauze conducts heat away from the
flame sufficient to prevent combustion, the principle on which the
Davey safety lamp works?

<snip>

> The flame will be much shorter when using premixed air, but one still
>has the height problem to accomplish the premixing. This is partially
>compensated by having this "mixing height" operate at a (much) lower
>temperature, so losses are less. But one has to pay for the blower and
>energy source to achieve the pre-mixing (Venturi or Koanda effect or
>wahtever). So far no one has offered a low cost method of doing the
>premixing without an external power source. Even if one had such an
>approach, one probably would have some operating difficulties (getting lit
>one way and then switching over?) This is a great challenge for everyone
on
>the list!! (Which remind me that I started some conversations with Andrew
>Heggie about alternatives to electricity for supplying higher pressure air.
>Andrew reminded me that the "brake" for spring wound toys is a "blower".)

Well I offered several possibilities, the clockwork or falling weight
one is to what you refer, I would not use the term brake, rather
"govern", my thought was that as power consumption of the fan is
related to the cube of the air velocity that the blower itself would
govern its speed within narrow limits (rather than need an
escapement), this governed speed could then also control the fuel
metering device, still a lot more complicated than natural draft.
Incidentally when considering even modest electric power like 3 watts
we will need to generate much more than this to store in a battery,
the best thing about this is the abundance of electronically com
mutated fans available from PCs.

>
> We also should be talking at the same time of ways to maintain a high
>temperature internally to assist in auto ignition - as you have implied in
>your question. Because catalysis is important in flame ignition
>temperature, we should be asking something about materials as well - maybe
>even a sacrificial material (if low cost). There has been zero discussion
>on this list about this topic. (note that the early movie projectors used
>lime ("limelight") where the gas flame hit in order to get an intense white
>light.

This was incandescence, not a catalytic effect, interesting in the
thermal-photo-voltaic scenario though, these gallenium arsenide
devices are reputedly 10 times more effective than Joule effect
devices so I can visualise a ring of incandescent material surrounded
by 3 Watts worth of these powering the blower, the semiconductor being
cooled by the secondary air flow from the blower.

AJH

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From dstill at epud.net Sat Nov 3 13:30:57 2001
From: dstill at epud.net (Dean Still)
Date: Tue Aug 31 21:37:15 2004
Subject: ETHOS
Message-ID: <005601c16453$61a5bf00$3c15210c@default>

Dear Friends,

Glad to see the Stoves list back in high gear. Thought I'd share a couple of
things that relate to stoves.

For three years Dr. Mark Bryden has been working with staff at Aprovecho. A
graduate student from Iowa State U spent a summer at Aprovecho doing a study
of the diameter and height and efficiency of the Rocket stove combustion
chamber. Matt Hagge, another ISU grad student is now helping us to set up
Grant Ballard Tremeer's experiment to analyze emissions from stoves. Mark is
getting some good data in another experiment at ISU to determine how the
heat from a fire effects the cooking pot. Mark has been a huge help on the
theory side and Aprovecho has helped to give him and his students some field
experience.

This last year, faculty and Mech. Eng. students from Dayton U have joined
Aprovecho and ISU in studying how to improve vernacular cooking stoves.
Dayton U students will also be heading down to Central America to help with
stove projects both doing research and building stoves. Dr Steve Benintendi
is working with Dayton U students to model and parametrically analyze the
heat transfer in a stove in an effort to theoretically determine which
design parameters most significantly affect the stove's operation. Dr
Margaret Pinnell is trying to characterize the thermal and mechanical
properties of various bricks (the Aprovecho homemade insulative ceramic-
Adobe, Baldosa and Commercial). They are doing thermal conductivity,
porosity (apparent and using image analysis), crushing strength, thermal
shock, etc. The class is aiming at finishing all testing by semester end so
that they can make a presentation in January. Dr Kevin Hallinan is the
Department Chairperson. He has initiated our working together and directs
the research and internships. We plan to do new research each semester.

At the same time, Dr Tami Bond with NOAA and Dr Anand Cousins from Seattle U
have been contributing to our efforts at collaboration. We have formed a
loose organization whose goal is to improve wood stoves and other
appropriate technologies for the families using them. It's called ETHOS:
Engineers in Technical Humanitarian Opportunities of Service. ETHOS
currently connects Aprovecho, Trees, Water, People, HELPS International,
ISU, Dayton U, and Seattle U. We hope to travel faster together, to use
scientific endeavor to directly help biomass users. The goal is to provide
a link between research and practice: as we learn how to make better stoves,
Aprovecho and its partner in dissemination,Trees, Water, People, and HELPS
International can help to pass this understanding on to cooks in Central
America (and around the world).

As results happen, we'll post them here.

Best,

Dean

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From andrew.heggie at dtn.ntl.com Sun Nov 4 07:25:40 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:15 2004
Subject: More on Bynsen, Meeker burners...
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <ub8autom5neggn6niv703drofmt5mjvgld@4ax.com>

Xpost cut as my interest is in the possibilities of using entrainment
devices in IDD cookstoves.

On Sat, 3 Nov 2001 07:40:51 -0700, "Thomas Reed" <tombreed@home.com>
wrote:

>Dear Andrew and All:
>
>I forgot to mention that the Meeker burner has a nice stamped metal Venturi
>mixing section you might like to study and copy.

I have not seen a Meeker burner, that the venturi is formed in a
stamping is interesting as IME this technology is within the grasp of
fairly rudimentary blacksmithing tools. I know a Coanda burner can be
hand made from steel pressings, as it works on a fluidics, surface
hugging, effect dimensions do not seem as critical as other
aspirators.

I did find reference to a poster session where a coal fired Meeker
burner was mentioned.

>
>Yes, there is an outer diffusion flame IF THE MIXTURE IS RICH. However, a
>lean mixture will burn completely in the primary cone (about 0.1 mm thick).
>The stoichiometric flame (correct oxygen) gives the highest temperature and
>heat transfer.

My memories of a bunsen burner are back in the days of "town" gas,
however I do use a propane torch and this does exhibit the inner and
outer cones, as the pressure is fixed and there is no means of varying
mixture I assumed it was set to a stoichiometric mix.

>This was all well known at the turn of the century and oxy-acetylene welding
>was king until electric arc welding took over.

Which reinforces the point that the "rules" are well known, the art is
in the application, the only new things I can see that modern
technology can bring to the table is cheap control via semi-condutor
devices, and this is a long way off for many people.

Whilst I have been happily playing with the Coanda burner and mooting
the possibility of using steam to power it I now see this too is
already in use in oil wells. The device is called a stedair burner.
http://www.kaldair.com/stedair_page.htm

Now this requires steam at 3 atmospheres, which I am not comfortable
with in a domestic situation, it does prove the possibilities however.
I can envisage a single helical coil containing a low mass of water
just below the cook pot, this then feeding steam to the Coanda nozzle
forming the secondary burner and cook pot support.

>Your fire-freak...... TOM REED

Pyromaniacally yours ;-)
AJH

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From lanny at roman.net Sun Nov 4 20:19:54 2001
From: lanny at roman.net (Lanny Henson)
Date: Tue Aug 31 21:37:15 2004
Subject: Heat Capturing Grate
Message-ID: <021d01c16597$c7108420$d1ba3cd0@default>

Heat-Capturing Grate.
So if one of the biggest loses of efficiency in a cook stove is in the
transfer of heat to the pot how about a heat-capturing grate? This grate would
capture some of the heat that would be lost and conduct it back to the cooking
pot or griddle. This grate would also improve convection by increasing the time
that the hot gas spends on the bottom of the pot or griddle.
Here is how it would work, heat from the burner/ fire is directed to the
center of the grate and the center of the pot. From the center of the pot the
hot gas travels in a path along the bottom of the pot which increases the time
that the hot gas contacts the bottom of the pot. The grate would have a small
surface area and low thermal mass in the center so as not to rob the heat
intended for the pot. As the grate gets larger toward the outside of the pot and
the hot gas gets closer to the exit, the surface area and the thermal mass of
the grate would increase to capture more heat. The pot would have first priority
to the convection heat but some of the heat not conducted to the pot from the
hot gas would be captured by the grate in a way that it can be conducted back to
the pot through direct contact. This heat captured by the grate could be
conducted back to the bottom of the pot for hours after the fire is out to
simmer or hold (160degF) food. The grate would be insulated and thermally
isolated from the stove body so the only way out for the heat is up to the
griddle or pot. There would be some losses. Straight conduction to the pot from
the grate should be very efficient heat transfer.
What do you think? Why will this not work?
Lanny

From ronallarson at qwest.net Mon Nov 5 08:09:56 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:15 2004
Subject: Heat Capturing Grate
In-Reply-To: <021d01c16597$c7108420$d1ba3cd0@default>
Message-ID: <009201c165fb$67937c00$9ff76641@computer>

Lanny (cc stovers):

We have had a mention of this
from time to time. However, I do not remember anyone giving any
experimental results of how they have been able to improve efficiency by
following the ideas you give below. I sure hope you can do a little more
research and report back.

I think there is a role here for
modeling - undoubtedly, there has been a lot of other similar work in
parallel fields. The financial support for stoves research has been so
small that we will have to look in other applications of heat transfer for good
ideas like this. I will make the same observation in a reply to
Andrew Heggie's recent note on the Coanda effect.

Both the Rocket stoves and the
natural draft charcoal making stoves have a substantial combustion chamber
height. I think the conduction material could occupy a large part of that
height. Dean Still recently wrote about the improved draft available with
a closed interior cylinder (4 inch inside a 6 inch). Perhaps all of that
could be used for heat conduction to the cook pot. Perhaps this interior
heat capture metal "grate" could do something to also add turbulence - so as to
get better air-fuel mixing.

Remember also that you can still
get heat transfer along the pot sides - so this is not either/or. The message
there is that lots of height is important. I think your "grate" will need
height as well.

You are the only one I remember
talking about fiberglass ropes. Could you report more on the costs and
where you are purchasing those ropes. Would they be a good enough thermal
insulator to support your improved thermal-conduction grate?

Thanks for your
input.

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:
Lanny Henson
To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Sent: Sunday, November 04, 2001 6:16
PM
Subject: Heat Capturing Grate

Heat-Capturing Grate.
So if one of the biggest loses of efficiency in a cook stove is in the
transfer of heat to the pot how about a heat-capturing grate? This grate would
capture some of the heat that would be lost and conduct it back to the cooking
pot or griddle. This grate would also improve convection by increasing the
time that the hot gas spends on the bottom of the pot or griddle.
Here is how it would work, heat from the burner/ fire is directed to the
center of the grate and the center of the pot. From the center of the pot the
hot gas travels in a path along the bottom of the pot which increases the time
that the hot gas contacts the bottom of the pot. The grate would have a small
surface area and low thermal mass in the center so as not to rob the heat
intended for the pot. As the grate gets larger toward the outside of the pot
and the hot gas gets closer to the exit, the surface area and the thermal mass
of the grate would increase to capture more heat. The pot would have first
priority to the convection heat but some of the heat not conducted to the pot
from the hot gas would be captured by the grate in a way that it can be
conducted back to the pot through direct contact. This heat captured by the
grate could be conducted back to the bottom of the pot for hours after the
fire is out to simmer or hold (160degF) food. The grate would be insulated and
thermally isolated from the stove body so the only way out for the heat is up
to the griddle or pot. There would be some losses. Straight conduction to the
pot from the grate should be very efficient heat transfer.
What do you think? Why will this not work?
Lanny

From ronallarson at qwest.net Mon Nov 5 09:52:49 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:15 2004
Subject: On Coanda effect
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <013e01c16609$b8ffdf80$9ff76641@computer>

Andrew and Stovers

(See next message for some notes about Andrew based on our visit in
mid-October)

Yesterday, you wrote:

<SNIP, but want to come back to the Reed/AJH material on the Meeker
burner)>

>Whilst I have been happily playing with the Coanda burner and mooting
>the possibility of using steam to power it I now see this too is
>already in use in oil wells. The device is called a stedair burner.
>http://www.kaldair.com/stedair_page.htm

(rwl): I visited that site and found it quite fascinating. For others,
I should report that Kaldair seems to be a firm dealing mainly with flaring
natural gas (sometimes with liquids). They seem to be British and have
gotten their start from work done in this area by BP (British Petroleum).
The Kaldair site gives good background on the Coanda effect (which I won't
try to repeat, but recommend for some who may be interested following these
added questions).

My questions:

1. The other products besides the "Stedair" seem to have promise for
cooking application as well. What was your reason for concentrating on the
"stedair"?

2. This company obviously is very skilled in gas combustion. How far
are they (located in Berks) from your own town?
Have you had any direct dealings with them? The one article on the subject
is written by a fellow in Houston, Texas. Is that the better location to
find burner technical expertise?

3. They seem to have settled on the Coanda effect because it is very
effective in promoting turbulence, entrainment, and mixing - all of which we
want to understand and control for stove improvement as well. However, they
always (??) seem to want a huge amount of extra air - and they are not using
the heat in the flare at all - just trying for clean combustion. They also
seem always to have the gas under pressure. Question - their literature
talked also about natural convection - but none of their products seemed to
have that feature. Do you think we could get adequate effects (such as exc
ess air closer to zero) with natural convection? Is there any way to
control the excess air, if you are dealling only with natural convection?

4. I especially liked what they said about the Azdair unit, which talks
about thin flames - produced from small holes and gas impinging upon a solid
sheet. I have ordered their technical literature and when received, will
probably have more questions.

Andrew also said:

>Now this requires steam at 3 atmospheres, which I am not comfortable
>within a domestic situation, it does prove the possibilities however.
>I can envisage a single helical coil containing a low mass of water
>just below the cook pot, this then feeding steam to the Coanda nozzle
>forming the secondary burner and cook pot support.

(RWL):
This is a very interesting aspect. I tend to agree with you that adding
steam features looks like it is getting too complicated. But I am very
impressed by what you did with steam drying of green wood. Please keep us
informed whenever you decide that steam may have advantages with simple cook
stoves. (Andrew and I also talked about various means of getting fan/blower
power for simple stoves - one possibility being from steam)

Thanks again. Ron

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From ronallarson at qwest.net Mon Nov 5 09:53:30 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:15 2004
Subject: London-#2: Andrew Heggie
Message-ID: <014201c16609$cc2fad60$9ff76641@computer>

Stovers:

A few notes about list member
Andrew Heggie and the type of "stoves" work he is doing.   I should
have sent this several weeks ago, when the information was fresh - but still
pertinent, as Andrew has been adding a lot of valuable information to "stoves"
recently including that on the Coanda effect.

1. Andrew is about 50 - two adult children
and one grandchild.  Very fit from outdoor life as nurseryman -
forester. Reminds me a lot of Alex English - knowledgeable about lots of
combustion areas. Has special interest (and lots of self-taught knowledge)
in charcoal production - with main goal of cost effective rapid drying of wood
so charcoal can be produced from waste woods (England has essentially stopped
production of lumber, so they (like the US, because of fire suppression) are
developing too much wood.

2. After picking us up from the RR station,
we had coffee and I began learning charcoal making from Andrew's
perspective. He has been doing a lot of testing with top-lighting - and
his work is very good. He works both in his backyard and, for larger
projects, in a nursery area.

3.   We saw some backyard equipment
and photos - then went for a Ploughman's
lunch (cheese, hard bread, and draft). Andrew lives in a very pleasant
quiet village about an hour south of London by train.  We saw the
school which has seen four generations from his family..

4.  We spent most of the afternoon at his
larger "lab" - seeing a demonstration of a half-scale steam dryer - Andrew's own
invention - and very impressive.   Needs power, but not much - is
intended for drying in remote areas. The drying, done in a few hours, was
impressive.

5. Also saw an interesting Incinerator that
Andrew is developing. Andrew can do all these well as he is a good welder,
etc..

6. After leaving that lab, we successfully
tried some top-down natural-draft "coking" of coal - as Andrew reported a while
back. Lots of experimentation still needed to get the right amount of
draft - but encouraging first results.

7.   We had a dinner of the famous
British "Fish and chips" - the real thing and the best I have ever had -
obtained from a small take-out store down the road.

Summary - I strongly recommend Andrew for
anyone looking for a great combination of (self-taught) technical expertise on
combustion and a real world ability to make things work. It appears he has
been doing almost all of his development work on his own - no salary. He
also is a very pleasant person to be around and has a lovely family (met wife
also, but only met one daughter, who soon is being transferred to very
responsible job in Boston)..

Andrew - thanks for being such a great host.
I wish you lived closer, so I could benefit more often from your willingness to
look at new ideas.

From tombreed at home.com Mon Nov 5 10:38:31 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:15 2004
Subject: On Coanda effect
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <001b01c1660f$b1063080$18e5b618@lakwod3.co.home.com>

Dear All:

Very interesting and I am sure many of us will try using the Coanda effect
for mixing and combustion.

See also

http://jnaudin.free.fr/html/coanda.htm

for explanation and videos of the effect....

Yours, TOM REED
Dr. Thomas Reed
The Biomass Energy Foundation
1810 Smith Rd., Golden, CO 80401
303 278 0558;
tombreed@home.com; www.woodgas.com
----- Original Message -----
From: "Ron Larson" <ronallarson@qwest.net>
To: "AJH" <andrew.heggie@dtn.ntl.com>; <Stoves@crest.org>
Sent: Monday, November 05, 2001 7:54 AM
Subject: On Coanda effect

> Andrew and Stovers
>
> (See next message for some notes about Andrew based on our visit in
> mid-October)
>
> Yesterday, you wrote:
>
> <SNIP, but want to come back to the Reed/AJH material on the Meeker
> burner)>
>
> >Whilst I have been happily playing with the Coanda burner and mooting
> >the possibility of using steam to power it I now see this too is
> >already in use in oil wells. The device is called a stedair burner.
> >http://www.kaldair.com/stedair_page.htm
>
> (rwl): I visited that site and found it quite fascinating. For
others,
> I should report that Kaldair seems to be a firm dealing mainly with
flaring
> natural gas (sometimes with liquids). They seem to be British and have
> gotten their start from work done in this area by BP (British Petroleum).
> The Kaldair site gives good background on the Coanda effect (which I won't
> try to repeat, but recommend for some who may be interested following
these
> added questions).
>
> My questions:
>
> 1. The other products besides the "Stedair" seem to have promise for
> cooking application as well. What was your reason for concentrating on
the
> "stedair"?
>
> 2. This company obviously is very skilled in gas combustion. How
far
> are they (located in Berks) from your own town?
> Have you had any direct dealings with them? The one article on the
subject
> is written by a fellow in Houston, Texas. Is that the better location to
> find burner technical expertise?
>
> 3. They seem to have settled on the Coanda effect because it is very
> effective in promoting turbulence, entrainment, and mixing - all of which
we
> want to understand and control for stove improvement as well. However,
they
> always (??) seem to want a huge amount of extra air - and they are not
using
> the heat in the flare at all - just trying for clean combustion. They also
> seem always to have the gas under pressure. Question - their literature
> talked also about natural convection - but none of their products seemed
to
> have that feature. Do you think we could get adequate effects (such as
exc
> ess air closer to zero) with natural convection? Is there any way to
> control the excess air, if you are dealling only with natural convection?
>
> 4. I especially liked what they said about the Azdair unit, which
talks
> about thin flames - produced from small holes and gas impinging upon a
solid
> sheet. I have ordered their technical literature and when received, will
> probably have more questions.
>
>
> Andrew also said:
>
> >Now this requires steam at 3 atmospheres, which I am not comfortable
> >within a domestic situation, it does prove the possibilities however.
> >I can envisage a single helical coil containing a low mass of water
> >just below the cook pot, this then feeding steam to the Coanda nozzle
> >forming the secondary burner and cook pot support.
>
> (RWL):
> This is a very interesting aspect. I tend to agree with you that
adding
> steam features looks like it is getting too complicated. But I am very
> impressed by what you did with steam drying of green wood. Please keep us
> informed whenever you decide that steam may have advantages with simple
cook
> stoves. (Andrew and I also talked about various means of getting
fan/blower
> power for simple stoves - one possibility being from steam)
>
> Thanks again. Ron
>
>
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From tami.bond at noaa.gov Mon Nov 5 11:42:51 2001
From: tami.bond at noaa.gov (Tami Bond)
Date: Tue Aug 31 21:37:16 2004
Subject: Heat Capturing Grate
In-Reply-To: <021d01c16597$c7108420$d1ba3cd0@default>
Message-ID: <3BE6C0FD.425C3EE@noaa.gov>

Dear Lanny,

This is similar to something I have thought, although I have nowhere
near the expertise of others on this list.

My idea is a little different: capturing heat from exhaust as in "heat
checkers" used in industrial preheat, sending heat back to pot and also
using the "checker" setup as a hot zone to help burnout of particles and
other pollutants. We need to get the heat to the pot, BUT we also need
to use the heat, while we have it, to get rid of the nasty stuff in the
exhaust. Dean's annular chamber might do enough of the trick.

I was thinking ceramic, but maybe steel would work. Both might be too
hard to manufacture and too expensive for the people who really need it.

Like your pictures. Keep up the good work.

Tami

> Lanny Henson wrote:
>
> Heat-Capturing Grate.
>
> So if one of the biggest loses of efficiency in a cook stove is in the
> transfer of heat to the pot how about a heat-capturing grate? This
> grate would capture some of the heat that would be lost and conduct it
> back to the cooking pot or griddle. This grate would also improve
> convection by increasing the time that the hot gas spends on the
> bottom of the pot or griddle.
>
> Here is how it would work, heat from the burner/ fire is directed to
> the center of the grate and the center of the pot. From the center of
> the pot the hot gas travels in a path along the bottom of the pot
> which increases the time that the hot gas contacts the bottom of the
> pot. The grate would have a small surface area and low thermal mass in
> the center so as not to rob the heat intended for the pot. As the
> grate gets larger toward the outside of the pot and the hot gas gets
> closer to the exit, the surface area and the thermal mass of the grate
> would increase to capture more heat. The pot would have first priority
> to the convection heat but some of the heat not conducted to the pot
> from the hot gas would be captured by the grate in a way that it can
> be conducted back to the pot through direct contact. This heat
> captured by the grate could be conducted back to the bottom of the pot
> for hours after the fire is out to simmer or hold (160degF) food. The
> grate would be insulated and thermally isolated from the stove body so
> the only way out for the heat is up to the griddle or pot. There would
> be some losses. Straight conduction to the pot from the grate should
> be very efficient heat transfer.
>
> What do you think? Why will this not work?
>
> Lanny

--
* --- * --- * --- * --- * --- * --- * --- * --- * --- * --- * --- *
Tami Bond tami.bond@noaa.gov
Postdoctoral Fellow (206) 526-4420
NOAA - PMEL Fax (206) 526-6744
7600 Sand Point Way NE
Seattle, WA 98115

"The universe is made of stories, not atoms." --Muriel Rukeyser
* --- * --- * --- * --- * --- * --- * --- * --- * --- * --- * --- *

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From psanders at ilstu.edu Tue Nov 6 09:58:37 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:16 2004
Subject: Kilns for cane leaves in India
In-Reply-To: <4.3.1.2.20011030091833.01a49190@mail.ilstu.edu>
Message-ID: <4.3.1.2.20011106081942.01a6f100@mail.ilstu.edu>

AD,

To all Stovers: AD and I have covered some of the basics in off-line
discussions, but I feel it is time to put it all back onto the Stoves
listserve. If you are NOT interested in the topic of making char from cane
leaves in India, please IGNORE all messages about this topic. We intend
to be VERY specific, and we are placing the messages on the Stoves list
JUST IN CASE some of you might be interested. (Note: ELK and Richard
Stanley are mentioned in this message, so it does relate to their work.)

AD's message (not previously placed on the Stoves listserve) has been moved
to here, and then my response is placed at the end.

At 02:54 PM 11/4/01 +0530, AD Karve wrote:
>Dear Paul,
>inquiries made in the local market revealed that ready made stainless steel
>barrels were available for about Rs. 400 each, (US$ 8), whereas the mild
>steel ones, which would have to be specially fabricated for us, would cost
>us about Rs. 300 (US$6) each. Our latest model of the kiln takes 9 barrels
>at a time. The operator needs two sets of barrels, so that while one set is
>being heated in the kiln, the second is kept ready with trash to be charred.
>In this way, he does not lose time (and heat) between batches. Thus, we need
>Rs. 7,200 for the stainless steel retorts and Rs. 5,400 for the mild steel
>retorts. All other costs are the same. Thus our revised cost estimate is
>about 200 Dollars for a kiln with stainless steel retorts and about US$ 180
>for a system having mild steel retorts.
>The question often asked to us is why we were opting for a small manual
>operation, when large scale systems producing even 100 tonnes of char per
>day were available. Our answer to this question is, that the large scale
>operation was not profitable. Agrowaste is diffused all over the
>countryside. We have ourselves seen, how costly it is to transport it from
>the field to a central processing factory. In a small scale operation, it
>becomes possible to itransport the processing machinery to the place where
>the agrowaste is available. Also, one needs only unskilled labour to help
>the operator, and because the operator takes the profit from this business,
>he does not take a salary for himself. Therefore the overheads are less and
>therefore the system can generate a profit.
>I asked our local bank about the best way to send money but they could not
>tell me anything concrete. I shall have to go to the head office, where they
>know more about foreign currency transactions.
>I am leaving for Delhi today and shall return in the evening of the 9th. We
>can resume our dialogue after the 9th of November.
>Yours A.D.Karve

Paul writes:
I am in agreement, and we will proceed.

I was under the impression that you had done more experimentation or had
some prior field trials away from your laboratory. So, that only means
that my involvement is coming in at a much earlier stage than I
thought. Which is fine. And that also means there is more room for
experimentation, and that there is MUCH MORE need for documentation of our
experiences. ALL aspects of our experiences, from expenditures to time to
acceptance by the people to post-processing of the char, etc, etc.

I am looking forward to this. But please re-confirm to me your own
commitment to doing what is needed, or to finding others who can do the
needed work on the ground in India. Perhaps more post-graduate student
labor is needed, as in "agricultural economics" etc that are fields beyond
the Karve specialties of physics and stoves and combustion. And ARTI is
involved in MANY diverse projects, so your attention must be spread over
several areas. (Same is true for me.) So, assistance is crucial. Perhaps
a small "focus group" or "team" for the project.

ALL numbers and opinions in science are subject to verification and
re-varification. And that applies to your earlier figures about the volume
of char that can be produced, and the financial cash-flow of tens of
millions of dollars.

So, please keep sending me more and more information, about the project and
about you and your wishes.

We truly do NEED a Rotary contact or two in your area!!!!!!!! HIGH
PRIORITY !!!!!!! We need one on e-mail who will be interested in
following along with the project. Soon we will have a project description,
which you can help distribute to the Rotarians in your area to help find
the right person or persons.

Concerning making briquettes out of the char, there are at least TWO
important additional ideas.

1. ELK in Kenya (Chardust, Inc) has a hand operated "extruder" of
compressed char. Have you seen the picture?

2. The "Legacy Foundation" (Richard Stanley) concept of briquettes is
EASY. I am doing it already in Mozambique. For India, char mixed with
fibrous binder, (that could be made from composted cane leaves! ) could be
made into briquettes at the field location. We would need to find the
acceptable sizes of briquettes for Indian use. But that is just part of
the "game".

Have a good trip.

Paul

>----- Original Message -----
>From: Paul S. Anderson <psanders@ilstu.edu>
>To: A.D. Karve <adkarve@pn2.vsnl.net.in>
>Cc: <karve@wmi.co.in>; Nick Nayak <nicholasnayak@aol.com>
>Sent: Friday, November 02, 2001 12:27 AM
>Subject: Re: Kilns for cane leaves in India
>
>
> > AD,
> >
> > My bank here would charge US$50.00 for a wire transfer to an international
> > destination, regardless of the amount being sent.
> >
> > If I sent the amount to a bank account inside the USA (example, an USA
> > account in New York of a non-USA bank), then the charge is only
> > $15.00. I await the information you will get from your bank.
> >
> > Your wrote:
> > >It is our experience that the mild steel drums corrode very fast. I
>have
> > >absolutely no experience with stainless steel.
> >
> > I would like to get some quantitative data about the above topic. "Very
> > fast" refers to about how long? And also the cost aspects.
> >
> > Do we have a student worker or assistant to whom you can give some routine
> > tasks? (I am concerned about asking too much of YOUR time.) I would like
> > to have a complete list of all materials (every bucket, barrel, rake,
> > basket, etc) that a person needs to use the method of char
> > production. What is the life span of each item? What is the cost? And
> > what are the alternatives?
> >
> > Also, I do not have a strong understanding of the "in-the-field" processes
> > that the worker must do. For example,
> >
> > how many hectares per ton of final char?
> >
> > How far must the worker travel to bring the leaves to the kiln?
> >
> > Or can the kiln be easily moved?
> >
> > Who owns the land, and who gives permission to collect the leaves?
> >
> > How will we process the char that is to be purchased? Costs, and
> > selling prices for what kinds of charcoal briquette products?
> >
> > Also, I again mention the importance of making contact with several of the
> > local Rotary Clubs. I encourage you to explore the situation of Rotary
>in
> > your area.
> >
> > Looking forward to your reply.
> >
> > Paul
> >
> > At 11:08 PM 11/1/01 +0530, A.D. Karve wrote:
> > >Dear Paul,
> > >My aquaintance in Maryland declined to bring dollars with him to India.
>He
> > >said that one was allowed to bring only $2000 cash into India. This is
>of
> > >course not true. If you brought more than $2000 with you in cash, you
>have
> > >to fill out a form at the airport, stating the amount that you were
> > >carrying. This declaration is officially recorded and and you get a
>stamped
> > >copy of it. Whenever you change dollars into Indian currency, the
> > >respective bank records the transaction on this document. When you leave
> > >India, this document shows that you were not smuggling foreign currency
>out
> > >of India, but that you were taking out your own unspent dollars.
> > > Obviously, he has his own reasons for not carrying too much cash with
>him,
> > >and I did not argue with him. We have received dollars in the past by
> > >cheque.
> > > The bank deducts some amount as service charge, but the process
> > > is very slow, taking more than a month before the
> > >money is ultimately paid into your account. Nowdays it is possible to
> > >transfer money electronically and you get the money within about
> > >a week. I shall ask my bank about it and if the charges are not too
>high,
> > >you may transfer the money electronically for the kilns as well as for
>the
> > >archives work that Priya is doing for the stovers. The service charges
>are
> > >proportionately lower, the larger the amount that is transfered. I shall
>let
> > >you know what my bank says.
> > >Comparing stainless steel retorts with ordinary steel ones is a good
> > >suggestion.
> > > I have asked my colleagues to buy one set of stainless steel drums and
> > >another set of mild steel drums and start the experiments right now. It
>is
> > >our experience that the mild steel drums corrode very fast. I have
> > >absolutely no experience with stainless steel. The idea of stainless
>steel
> > >was suggested to us by Paul Hait of Pyromid
> > >Yours A.D.Karve
> > [[[prior messages have been deleted]]]
> >
> >
> > Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> > Dept of Geography - Geology (Box 4400), Illinois State University
> > Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> > E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
> >
> >

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

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From andrew.heggie at dtn.ntl.com Tue Nov 6 12:58:29 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:16 2004
Subject: London-#2: Andrew Heggie
In-Reply-To: <014201c16609$cc2fad60$9ff76641@computer>
Message-ID: <tq4gutg4e0h97kf8b9kccvu9fqrsun9at0@4ax.com>

On Mon, 5 Nov 2001 07:54:39 -0700, "Ron Larson"
<ronallarson@qwest.net> wrote:

>
> A few notes about list member Andrew Heggie and the type of "stoves" work he is doing.
Crikey Ronal, I'm still blushing!
>
>1. Andrew is about 50 - two adult children and one grandchild. Very fit from outdoor life as nurseryman - forester. Reminds me a lot of Alex English - knowledgeable about lots of combustion areas. Has special interest (and lots of self-taught knowledge) in charcoal production - with main goal of cost effective rapid drying of wood so charcoal can be produced from waste woods (England has essentially stopped production of lumber, so they (like the US, because of fire suppression) are developing too much wood.

If I can just clarify a couple of points, the recently planted forests
of UK are producing more timber than ever, it is the woods I work in
that have problems in marketing produce. Forestry pays on the large
scale where modern harvesting machines can be deployed, these severely
undercut the harvesting rates of traditional methods. Also the
machines typically displace 15+ motor manual workers.

>4. We spent most of the afternoon at his larger "lab" - seeing a demonstration of a half-scale steam dryer - Andrew's own invention - and very impressive. Needs power, but not much - is intended for drying in remote areas. The drying, done in a few hours, was impressive.

Whilst I decided on the concept independently, via a lateral route,
the technique has been well understood and employed in industry. The
little demonstrator I have was built by my collaborators.
>
>5. Also saw an interesting Incinerator that Andrew is developing. Andrew can do all these well as he is a good welder, etc..

Well I can stick bits of metal together, my colleagues refuse to allow
me to show my "heath Robinson" devices to their customers :-(.

>Summary - I strongly recommend Andrew for anyone looking for a great combination of (self-taught) technical expertise on combustion and a real world ability to make things work. It appears he has been doing almost all of his development work on his own - no salary.

Well being self taught is not to be recommended, I blew my chances of
further education when I was 19. I do often lose enthusiasm because of
lack of funds for developing ideas and whilst other bodies seem to
fritter opportunities away, we shall get there in the end.

>Andrew - thanks for being such a great host.

My pleasure, I thoroughly enjoyed myself.
AJH

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From andrew.heggie at dtn.ntl.com Tue Nov 6 12:59:15 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:16 2004
Subject: Gasifier casting furnace
In-Reply-To: <3BE41774.FFA3D4B3@home.com>
Message-ID: <se7gut82vpskf945buavj3ohrq5k2pksd1@4ax.com>

On Mon, 5 Nov 2001 06:08:24 -0700, "Thomas Reed" <tombreed@home.com>
wrote:

>Dear All:
>
>I have been sitting on this too long...

Better late than never, it looks fantastic, anyone up for further
discussion on this?

The ejector is crude, how efficient can we get one to be? Obviously
there is scope for a coanda nozzle here but again this needs high
pressures. Its appeal to me are that the device is unlikely to clog up
with tar and can be fabricated from cans, the slot dimensions are not
critical but the angles are.

This dasifier seems to have some of the attributes of the idd. If the
rate of movement of the pyrolysis front is matched by char consumption
of the bottom then we should see a stable gas production. I would have
expected the CO generator formed by the bottom section to be a smaller
diameter than the top to increase gas velocity through the char bed.

AJH

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From psanders at ilstu.edu Tue Nov 6 13:07:44 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:16 2004
Subject: More on best stoves
Message-ID: <4.3.1.2.20011106102925.01a6ddd0@mail.ilstu.edu>

Stovers,

I have more to report today on recent work with gasification.

1. I obtain strong flame and very little evident soot during the
gasification/combustion stage (prior to the burning of the charcoal). The
AMOUNT of heat from the gasification process is impressive and screams to
me that charcoal production WITHOUT USEFUL BURNING OF THE GASSES is where
tremendous waste occurs.

Comment: I am becoming even more highly convinced of the value of the
gasification process (ala the Reed-Larson style of IDD gasification). I
believe that the fuel making processes of Richard Stanley (Legacy
Foundation) could produce appropriate fuel "units" (as in mini-briquettes)
from unconsolidated biomass, but that is a separate question.

2. Size (amount) of charcoal after gasification seems to be substantial (
more than 50% of the volume of fuel pellets used for gasification).

3. I need "reasonable" air supply to ignite the process, but later I need
to restrict the primary air to VERY low amounts. Currently, the air leaks
in my gasifier container are excessive, so I am trying to seal it better at
the bottom. I believe that a 1/8 th inch ( 4 mm.) diameter hole could be
more than enough air for the 4 inch diameter gasifier chamber I am
using. Someone wrote recently that the some oxygen is released in the
gasification process, thereby "fueling" the primary fire. I am sure that
amount of oxygen will depend on the nature of the biomass.

Question #1: does anyone have understandable info on this source of
oxygen from within the fuel, or is it not an issue?

3. I am able to easily save the charcoal. I do NOT want to burn it in the
same gasifier unit because it is inefficient there and I suspect that the
heat-stress reduces the life of the gasifier unit. My alternatives are A.
to quench the charcoal in water, or B. to place the hot charcoal into some
more appropriate stove. (and for what purpose in the stove for charcoal?
slow cooking? warming? grilling steaks (not in Developing Societies)? or
what? )

Therefore: Question #2. Do we have a (or several) appropriate stoves for
use of the charcoal? For example, would the charcoal be highly
appropriate for some type of oven for bread, etc.? Charcoal needs to be
close to the object being warmed, right? Basically, I am saying that I
want the charcoal removed from the gasifier? What do I do with it?

###########

I have made a list to issues to be considered in constructing one or more
"marketable" (meaning appropriate) gasifier stoves:

Priority issues:

Diameter of
gasifier (lower unit)
burner (upper unit)
Height
gasifier
burner
Overlap of burner bottom down over the top of the gasifier, which relates to--
Secondary air controls
Primary air control
Fuel types:
"standard fuel #1" I have chosen wood pellets (as for pellet stoves)
because this fuel is available, cheap, consistent quality, needs no
processing by me, easily measured.
"standard fuel #2" To be defined
(left for later): hundreds of other fuels that are difficult to replicate
in many areas, but that need to be eventually tested.

Fuel amounts (related to diameter of the gasifier, height of the fill, and
the desired length of the burn)

OF COURSE EMISSIONS AND EFFICIENCY need to be considered, but that will
need to be done by others after we get some better idea of the basic
physical structure of the stove.

Secondary issues:

Materials of construction of the components:
Aluminum (easy to work with, transfers heat well, but ultimately too
expensive?)
Iron/steel/ "tin cans" (readily available).
mud/clay/etc. (just to keep in mind at present)

Taper of the component parts (does it make a difference?)
Forced-air enhancements (options to consider)
Multiple burners (side by side for bigger stoves)
Physical appearance, including the "support" of the the upper burner,
complete with a stove-top.

This is not a small list, and maybe other issues should be added.

My experimentation is quite simple and I hope to explain in a week or two
what I am doing so that others (read: you) can replicate and further
experiment along with me.

Meanwhile, may I suggest that you start saving all metal cans with
diameters from 3 to 7 inches. (smile :-)) ).

Paul

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From Tami.Bond at noaa.gov Tue Nov 6 14:21:00 2001
From: Tami.Bond at noaa.gov (Tami Bond)
Date: Tue Aug 31 21:37:16 2004
Subject: More on best stoves
Message-ID: <10fe810874.1087410fe8@pmel.noaa.gov>

Paul,

Congratulations to you on your great progress!

> AMOUNT of heat from the gasification process is impressive and
> screams to me that charcoal production WITHOUT USEFUL BURNING OF THE
> GASSES is where tremendous waste occurs.

Agree wholeheartedly. I know most stovers are interested in biomass but
I have a "thing" for coal and China. So imagine the same with coal of
40% volatile matter. It's impossible to keep the coal from sooting in
standard burning (as done by stove users), for various reasons; also
very difficult to control.

As soon as all my equipment works at the same time (very low
probability) I am going to get some real particle numbers on coal
burning. I am getting very close now and did a practice burn last
Friday. After I measure the coal I have, I want to try IDD on this high-
volatile bituminous. Andrew has told me a little about the process, and
I'll get more info from Ron too, and perhaps see if it is a viable
method for reducing sooting. Has anyone besides Andrew tried this with
coal? How 'bout the South African contingent?

> Question #1: does anyone have understandable info on this source
> of oxygen from within the fuel, or is it not an issue?

There are many papers on pyrolysis of biomass. Try _Energy and Fuels_
journal? I don't have time to go digging on this. But first ask what
information we're looking for. How would it help you if you understood
where oxygen is coming from? Mightn't it be quicker and more robust to
develop some kind of metric for determining when your primary air is
just sufficient-- some easily-measured exhaust-gas content?

> B. to place the hot charcoal
> into some more appropriate stove. (and for what purpose in the stove
> for charcoal? slow cooking? warming? grilling steaks

How about heating? It's not needed in many locations, but people in
China bring charcoal into their homes and burn it in a flat dish to
warm themselves "smokelessly". There are generations-old family
charcoaling businesses there. Again, the potential heat from the gas
escape is wasted. The charcoaling is sometimes done in mountain caves
that can be sealed up to restrict air.

I imagine it would be pretty hard to get the users to switch stoves in
the middle of the combustion process. They probably have enough to do
with preparing the food, feeding the fire, etc. Anyone know? What about
a transportable grate that fit in both "gasification" and "charcoal"
stoves? People with lots of experience with gasification (Tom, etc.)
probably have ideas on this. I'm still a newbie & learning my way
around, but happy to listen.

This is mostly babbling so I'll sign off now.

Tami

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From psanders at ilstu.edu Tue Nov 6 16:31:56 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:16 2004
Subject: More on best stoves
In-Reply-To: <20011106182146.IHVS24707.fep02-svc.ttyl.com@localhost>
Message-ID: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>

Ken,

I like the idea (below). But because I must (currently) remove the
gasifier unit in order to refill it, I can just as easily dump it into a
container such as you suggest. Also, I am concerned about leaking primary
air into the gasification chamber.

However, my earlier experiences (perhaps with air leaks) was that the
charcoal did NOT extinguish (starved of oxygen). Do you have info to
share about how to smother the hot charcoal? If air leaks in from the top
(sealed-bottom cans are easy to obtain), with the charcoal extinguish itself?

Paul

At 06:21 PM 11/6/01 +0000, you wrote:
>Paul and stove listers,
>
>Might I suggest having a charcoal storage container below your gasifier.
>This can be just another tin can but with a sliding or "butterfly valve"
>rotating lid. When the gasification is complete, the bottom of the
>gasifying can is slid or rotated and the charcoal falls into an airtight
>container and smoulders until the oxygen is consumed - but still
>contributes some heat (for a while as it extinguishes), upwards into the
>gasification zone.
>
>The container should be sized to allow charcoal from 2 or more burns to be
>stored.
>
>In this way you do not lose the stored heat or end up with wet quenched
>charcoal.
>
>Ken Boak
>
>
>_______________________________________________________________________
>Never pay another Internet phone bill!
>Freeserve AnyTime, for all the Internet access you want, day and night,
>only £12.99 per month.
>Sign-up at http://www.freeserve.com/time/anytime

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From andrew.heggie at dtn.ntl.com Tue Nov 6 16:42:21 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:16 2004
Subject: On Coanda effect
In-Reply-To: <3BDF624C.D928457D@cybershamanix.com>
Message-ID: <m5mgutchkld0c77a63vujs21n1q282rjuq@4ax.com>

On Mon, 5 Nov 2001 07:54:07 -0700, "Ron Larson"
<ronallarson@qwest.net> wrote:

>
>My questions:
>
> 1. The other products besides the "Stedair" seem to have promise for
>cooking application as well. What was your reason for concentrating on the
>"stedair"?

I was only pointing out that the idea of using steam as the power
fluid in a coanda nozzle (as I had propounded for the top "secondary"
burner of an IDD stove) was not as novel as I thought.
>
> 2. This company obviously is very skilled in gas combustion. How far
>are they (located in Berks) from your own town?

30 miles

>Have you had any direct dealings with them?

No I came across them via a web search.

> The one article on the subject
>is written by a fellow in Houston, Texas. Is that the better location to
>find burner technical expertise?

Well I see from a mate who is an oil production engineer and chemist,
that he is posting from a Shell domain and is in Houston so it must be
the place to be.
>
> 3. They seem to have settled on the Coanda effect because it is very
>effective in promoting turbulence, entrainment, and mixing - all of which we
>want to understand and control for stove improvement as well. However, they
>always (??) seem to want a huge amount of extra air - and they are not using
>the heat in the flare at all - just trying for clean combustion. They also
>seem always to have the gas under pressure. Question - their literature
>talked also about natural convection - but none of their products seemed to
>have that feature. Do you think we could get adequate effects (such as exc
>ess air closer to zero) with natural convection?

Nope, IMO you either need turbulence or excess air to make sure the
chances of a fuel molecule being met by an oxygen molecule are high
enough,

>Is there any way to
>control the excess air, if you are dealling only with natural convection?

Retention time in the combustion area is about the only other thing
you can play with.

>
>(RWL):
> This is a very interesting aspect. I tend to agree with you that adding
>steam features looks like it is getting too complicated. But I am very
>impressed by what you did with steam drying of green wood. Please keep us
>informed whenever you decide that steam may have advantages with simple cook
>stoves. (Andrew and I also talked about various means of getting fan/blower
>power for simple stoves - one possibility being from steam)

Well my first step is to mount the coanda burner which Kit Wallis
loaned me over the idd stove, I have started this and shall have a run
using compressed air but it may take a while now it is dark when I get
home. Incidentally looking at its construction I think it could be
done with tin cans and a bit of metal spinning, if it is possible to
anneal food cans. This puts it in the reach of anyone with a wood
lathe.

AJH

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From lanny at roman.net Tue Nov 6 19:39:14 2001
From: lanny at roman.net (Lanny Henson)
Date: Tue Aug 31 21:37:16 2004
Subject: Heat Capturing Grate
Message-ID: <00b301c16724$67369b00$75ba3cd0@default>

Ron and Stovers,
I will build the heat-capturing grate that I have in mind and then go from
there. We will see.
You ask about fiberglass rope. This is a very handy material and is good to
2000 deg F. It is also known as stove rope and can be purchased at most hardware
stores. The material that I used is a larger size 1" low density. It is about
$1.50 per foot. I can send you some. I can see many uses for fiberglass rope, as
spacing and sealing jacket materials, for double walling exhaust stacks, just
use two pipes and a ring of rope on each as spacers, how about a spiral of rope
around a pot with a jacket to improve heat transfer by increasing the time hot
gas spends on the pot.
Lanny
<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:lanny@roman.net"
title=lanny@roman.net>Lanny Henson ; <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Sent: Monday, November 05, 2001 8:11
AM
Subject: Re: Heat Capturing Grate

Lanny (cc stovers):

We have had a mention of this
from time to time. However, I do not remember anyone giving any
experimental results of how they have been able to improve efficiency by
following the ideas you give below. I sure hope you can do a little more
research and report back.

I think there is a role here
for modeling - undoubtedly, there has been a lot of other similar work
in parallel fields. The financial support for stoves research has been
so small that we will have to look in other applications of heat transfer for
good ideas like this. I will make the same observation in a reply
to Andrew Heggie's recent note on the Coanda effect.

Both the Rocket stoves and the
natural draft charcoal making stoves have a substantial combustion chamber
height. I think the conduction material could occupy a large part of
that height. Dean Still recently wrote about the improved draft
available with a closed interior cylinder (4 inch inside a 6 inch).
Perhaps all of that could be used for heat conduction to the cook pot.
Perhaps this interior heat capture metal "grate" could do something to also
add turbulence - so as to get better air-fuel mixing.

Remember also that you can
still get heat transfer along the pot sides - so this is not either/or. The
message there is that lots of height is important. I think your "grate"
will need height as well.

You are the only one I
remember talking about fiberglass ropes. Could you report more on the
costs and where you are purchasing those ropes. Would they be a good
enough thermal insulator to support your improved thermal-conduction
grate?

Thanks for your
input.

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:
Lanny Henson

To: <A href="mailto:stoves@crest.org"
title=stoves@crest.org>stoves@crest.org
Sent: Sunday, November 04, 2001 6:16
PM
Subject: Heat Capturing Grate

Heat-Capturing Grate.
So if one of the biggest loses of efficiency in a cook stove is in the
transfer of heat to the pot how about a heat-capturing grate? This grate
would capture some of the heat that would be lost and conduct it back to the
cooking pot or griddle. This grate would also improve convection by
increasing the time that the hot gas spends on the bottom of the pot or
griddle.
Here is how it would work, heat from the burner/ fire is directed to the
center of the grate and the center of the pot. From the center of the pot
the hot gas travels in a path along the bottom of the pot which increases
the time that the hot gas contacts the bottom of the pot. The grate would
have a small surface area and low thermal mass in the center so as not to
rob the heat intended for the pot. As the grate gets larger toward the
outside of the pot and the hot gas gets closer to the exit, the surface area
and the thermal mass of the grate would increase to capture more heat. The
pot would have first priority to the convection heat but some of the heat
not conducted to the pot from the hot gas would be captured by the grate in
a way that it can be conducted back to the pot through direct contact. This
heat captured by the grate could be conducted back to the bottom of the pot
for hours after the fire is out to simmer or hold (160degF) food. The grate
would be insulated and thermally isolated from the stove body so the only
way out for the heat is up to the griddle or pot. There would be some
losses. Straight conduction to the pot from the grate should be very
efficient heat transfer.
What do you think? Why will this not work?
Lanny

From kchishol at fox.nstn.ca Tue Nov 6 22:00:55 2001
From: kchishol at fox.nstn.ca (Kevin Chisholm)
Date: Tue Aug 31 21:37:16 2004
Subject: More on best stoves
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <000c01c16737$e8390e00$f019059a@kevin>

Dear Paul

Charcoal will extinguish itself in short order in an airtight container. If
it doesn't extinguish, then it is because air is leaking in.

Air leaking in from the top wil "fuel the fire." Fundamentally, the charcoal
cannot sustain combustion without oxygen.

Consider if there was a single hole, 1/4" diameter, anywhere, in an
otherwise airtight container. As the container cooled, it would initially
draw air in, but then combustion and heating would occur, and the products
of combustion would be expelled. AS they are being expelled, no air is
entering, and the charcoal tends to cool. Then the process repeats itself.

Consider if ther were two 1/4" holesanywhere in the container, so long as
they were at different elevations; then a "stack effect" would be created.

Hope this helps visualize the problem.

Kevin Chisholm
----- Original Message -----
From: "Paul S. Anderson" <psanders@ilstu.edu>
To: <kenboak@stirlingservice.freeserve.co.uk>; "Apolinário J Malawene"
<ajmalawene01@hotmail.com>; "Bob and Karla Weldon" <bobkarlaweldon@cs.com>;
"Ed Francis" <cfranc@ilstu.edu>; "Tsamba--Alberto Julio"
<ajtsamba@zebra.uem.mz>; <stoves@crest.org>
Sent: Tuesday, November 06, 2001 5:36 PM
Subject: Re: More on best stoves

Ken,

Paul

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From hseaver at cybershamanix.com Wed Nov 7 01:28:52 2001
From: hseaver at cybershamanix.com (Harmon Seaver)
Date: Tue Aug 31 21:37:16 2004
Subject: IDD & Charcoal(was Re: More on best stoves)
In-Reply-To: <4.3.1.2.20011106102925.01a6ddd0@mail.ilstu.edu>
Message-ID: <3BE8D483.3CBF04FC@cybershamanix.com>

I understand the desire to save the charcoal (for resale or later
use) in some sectors, but for my own uses, I'm thinking it would be best
if it all burned. Paul mentioned this possibly being hard on the stove,
but I'd assume not if you're using riser sleeves or some other ceramic
insulation. Are there any other drawbacks or difficulties in allowing
the charcoal to just burn?

--
Harmon Seaver, MLIS
CyberShamanix
Work 920-203-9633
Home 920-233-5820
hseaver@cybershamanix.com
http://www.cybershamanix.com/resume.html

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From andrew.heggie at dtn.ntl.com Wed Nov 7 05:00:52 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:16 2004
Subject: IDD & Charcoal(was Re: More on best stoves)
In-Reply-To: <4.3.1.2.20011106102925.01a6ddd0@mail.ilstu.edu>
Message-ID: <7ithut491e6cdkjnd7vktb6oagirvgcrh5@4ax.com>

On Wed, 07 Nov 2001 00:28:32 -0600, Harmon Seaver
<hseaver@cybershamanix.com> wrote:

> I understand the desire to save the charcoal (for resale or later
>use) in some sectors, but for my own uses, I'm thinking it would be best
>if it all burned.

Unless the household has use for charcoal burning as well I wonder if
there is any likelihood of trading these small quantities. I think a
number of us consider that the char residue is not a major attribute
in domestic cooking, there is a possible exception which Alex and I
discussed on list, it attracted attention in an FAO newsletter at the
time, that was the possibility of a communal gasifier-ic engine using
the char to perform pumping/grinding/generation tasks. The theory
being that a simple CO generator is easier to run than an full blown
downdraft gasifier, though power is much reduced.

> Paul mentioned this possibly being hard on the stove,
>but I'd assume not if you're using riser sleeves or some other ceramic
>insulation. Are there any other drawbacks or difficulties in allowing
>the charcoal to just burn?

Lots of problems, the first is that the idd stove produces its flame
as a diffuse combination of pyrolysis products. Most of the gases for
this flame come from the secondary air slit and the fuel gas is of a
high cv. This is because the primary air requirement is low so the
offgas is little diluted by the primary combustion products. The fuel
holder is the primary combustion zone (where flaming pyrolysis occurs)
and temperatures need only be sufficient to enable pyrolysis, hence a
simple steel container will suffice.

Once the flaming pyrolysis front reaches the bottom of the stove then
charcoal burns, with low primary air velocities it burns completely to
CO2 and a lot of heat is released at the bottom of the stove, the only
flue gas is CO2 (plus combustion products of higher volatiles left in
the char) and it has the whole of the char column plus secondary air
entrainment plus secondary air combustion space to lose heat from, it
will not contribute a lot to cooking.

To turn this into an updraft gasifier you need to increase primary
airflow enough to form a deep hot bed (Tom Reed estimates it must be
20 article diameters deep) that will react the CO2 initially produced
to CO, the CO then being burned with secondary air as in the idd mode.
It is unlikely this can be done with natural draught in the absence of
a long chimney (which is precluded by the need to sit a pot on the
outlet). Also the CO generating region is >700C and quickly eats
through a steel container, though a simple flower pot in the bottom
will increase life.

My solution is to recycle the char, minus any fines and ash, with the
next fuel load. With small twigs char production does not seem to
exceed 25% of the original mass, so any char mixed homogeneously with
the fuel load exhibits a half life in the fuel cycle, though I have
not tried this over more than a few burns.

AJH

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From pverhaart at optusnet.com.au Wed Nov 7 05:06:16 2001
From: pverhaart at optusnet.com.au (Peter Verhaart)
Date: Tue Aug 31 21:37:16 2004
Subject: Fwd: Re: On Coanda effect
Message-ID: <5.1.0.14.2.20011107195709.00a93340@mail.optusnet.com.au>

>Date: Tue, 6 Nov 2001 07:47:25 -0700
>From: "Ron Larson" <ronallarson@qwest.net>
>To: "Peter Verhaart" <pverhaart@optusnet.com.au>
>Subject: Re: On Coanda effect
>X-Mailer: Microsoft Outlook Express 5.00.2615.200
>
>Piet -
>
> I have some of the questions. The Coanda effect value is not yet clear
>for "simple" stoves - but it does seem to work for Kaldair. Did you visit
>lots of parts of their site?
>
> But I think you meant this to go to all. Why not resend?
>
>Ron

I am forwarding this to the Stoves List, I should look at the sender's
address once in a while.

I visited the site but confined myself to the flare part. I think for the
Coanda effect you need higher velocities than we get in our non-externally
owered stoves.

Thank you, Ronal.

Piet

>----- Original Message -----
>From: Peter Verhaart <pverhaart@optusnet.com.au>
>To: Ron Larson <ronallarson@qwest.net>
>Sent: Tuesday, November 06, 2001 3:53 AM
>Subject: Re: On Coanda effect
>
>
> >
> >
> > At 07:54 5/11/01 -0700, you wrote:
> > >Andrew and Stovers
> > >
> > >(rwl): I visited that site and found it quite fascinating. For
>others,
> > >I should report that Kaldair seems to be a firm dealing mainly with
>flaring
> > >natural gas (sometimes with liquids). They seem to be British and have
> > >gotten their start from work done in this area by BP (British Petroleum).
> > >The Kaldair site gives good background on the Coanda effect (which I
>won't
> > >try to repeat, but recommend for some who may be interested following
>these
> > >added questions).
> >
> >
> > I always thought the Coanda effect is what infuriates us when the tea (or
> > even coffee) runs down the outside of the spout instead of, as the
>designer
> > has ordered, form a decent jet that directs the liquid into the cup. It
>has
> > to do with a boundary layer that sticks to the main stream.
> > I don't see how that could promote combustion.
> > Regarding flares, I think we are up against the very opposite. Flares
> > usually have to burn gases with a high combustion value (hydrocarbons).
> > Diluting them with steam enlarges the volume thus enabling diffusion of
> > air. Further the steam can entrain air when needed, forming a premixed
> > flame (even if the mixture remains rich, the sooting will be less).
> > We stovers are dealing with a low calorific gas with a variable
>composition
> > as well as a variable rate of flow. No wonder sensible people turn to
> > liquid and gaseous fuels.
> >
> > Piet
> >
> >

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From andrew.heggie at dtn.ntl.com Wed Nov 7 05:39:20 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:16 2004
Subject: Fwd: Re: On Coanda effect
In-Reply-To: <5.1.0.14.2.20011107195709.00a93340@mail.optusnet.com.au>
Message-ID: <ti3iutgj4oq39a8tuk8l3alpb8mn99jei7@4ax.com>

On Wed, 07 Nov 2001 20:05:03 +1000, Peter Verhaart
<pverhaart@optusnet.com.au> wrote:

>
>I am forwarding this to the Stoves List, I should look at the sender's
>address once in a while.
No, the list should conform to common software and carry a reply to:
header, I frequently end up replying to poster instead of list.
>
>I visited the site but confined myself to the flare part. I think for the
>Coanda effect you need higher velocities than we get in our non-externally
>owered stoves.

I am certain this effect is of no importance in natural draft stoves.
However that need not rule it out in otherwise "powerless" situations.
AJH

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From tombreed at home.com Wed Nov 7 07:56:44 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:16 2004
Subject: Charcoal - To burn or produce?
In-Reply-To: <4.3.1.2.20011106102925.01a6ddd0@mail.ilstu.edu>
Message-ID: <001601c1678a$1e09efc0$18e5b618@lakwod3.co.home.com>

Dear Stovers All:

When I first operated an inverted downdraft gasifier-stove in 1985 I was
delighted how easily it made a combustible gas - but not happy about
charcoal production (~20% here in Dry Denver).

When Ron Larson contacted me in 1995 to ask if I knew how to use the
volatiles from charcoal making I was happy to say that I was working on
stoves that did both. Ron convinced me that the charcoal would be a
positive by-product in some parts of the world where charcoal is used in the
cities. Two years later we published our paper on natural draft WoodGas
stoves.

Nevertheless, from the viewpoint of many cooks, charcoal production was a
nuisance, since up to 1/3 of the fuel value is in the charcoal.
~~~~~
The problem is that biomass is really two fuels:

1) the volatiles that are released between 300 and 400 C

2) the charcoal that remains afterward.

I have found two solutions to this.

1) With proper control of primary (gasification) air and combustion air, one
can use VERY little primary air to gasify dry fuel (< 1/1 Air/fuel ratio),
moderate primary air for wet fuels (up to ~ 30%moisture, ~3/1 A/F) and lots
of air (6/1 A/F)to gasify charcoal to a beautifully burning CO/H2 flame.
This requires some attention from the cook to either change the ratio when
the volatiles have burned or add more fuel on top of the hot charcoal
(approximately 10 g/min to prevent big flare).

2) By burning wetter and wetter fuels the problem disappears because the
charcoal needs to burn to dry the fuel to permit flame propagation.

There may be other ways to consume biomass as if it were a single fuel and I
am investigating them.

Onward....... TOM REED BEF

Dr. Thomas Reed
The Biomass Energy Foundation
1810 Smith Rd., Golden, CO 80401
303 278 0558;
tombreed@home.com; www.woodgas.com
----- Original Message -----
From: "Harmon Seaver" <hseaver@cybershamanix.com>
To: <stoves@crest.org>
Sent: Tuesday, November 06, 2001 11:28 PM
Subject: IDD & Charcoal(was Re: More on best stoves)

> I understand the desire to save the charcoal (for resale or later
> use) in some sectors, but for my own uses, I'm thinking it would be best
> if it all burned. Paul mentioned this possibly being hard on the stove,
> but I'd assume not if you're using riser sleeves or some other ceramic
> insulation. Are there any other drawbacks or difficulties in allowing
> the charcoal to just burn?
>
> --
> Harmon Seaver, MLIS
> CyberShamanix
> Work 920-203-9633
> Home 920-233-5820
> hseaver@cybershamanix.com
> http://www.cybershamanix.com/resume.html
>
>
>
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From tombreed at home.com Wed Nov 7 08:58:02 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:16 2004
Subject: Charcoal post combustion..
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <00a901c16792$99667780$18e5b618@lakwod3.co.home.com>

Dear Kevin and all:

It is VERY difficult to extinguish charcoal because of the effect Kevin so
well discussed below.

I have had "extinguished stoves" be still warm a day later.

Also, leaks can generate CO - deadly if you get enough.

So make airtight extinction really tight - or spray on water!

TOM
Dr. Thomas Reed
The Biomass Energy Foundation
1810 Smith Rd., Golden, CO 80401
303 278 0558;
tombreed@home.com; www.woodgas.com
----- Original Message -----
From: "Kevin Chisholm" <kchishol@fox.nstn.ca>
To: <kenboak@stirlingservice.freeserve.co.uk>; "Apolinário J Malawene"
<ajmalawene01@hotmail.com>; "Bob and Karla Weldon" <bobkarlaweldon@cs.com>;
"Ed Francis" <cfranc@ilstu.edu>; "Tsamba--Alberto Julio"
<ajtsamba@zebra.uem.mz>; <stoves@crest.org>; "Paul S. Anderson"
<psanders@ilstu.edu>
Sent: Tuesday, November 06, 2001 7:57 PM
Subject: Re: More on best stoves

> Dear Paul
>
> Charcoal will extinguish itself in short order in an airtight container.
If
> it doesn't extinguish, then it is because air is leaking in.
>
> Air leaking in from the top wil "fuel the fire." Fundamentally, the
charcoal
> cannot sustain combustion without oxygen.
>
> Consider if there was a single hole, 1/4" diameter, anywhere, in an
> otherwise airtight container. As the container cooled, it would initially
> draw air in, but then combustion and heating would occur, and the products
> of combustion would be expelled. AS they are being expelled, no air is
> entering, and the charcoal tends to cool. Then the process repeats itself.
>
> Consider if ther were two 1/4" holesanywhere in the container, so long as
> they were at different elevations; then a "stack effect" would be created.
>
> Hope this helps visualize the problem.
>
> Kevin Chisholm
> ----- Original Message -----
> From: "Paul S. Anderson" <psanders@ilstu.edu>
> To: <kenboak@stirlingservice.freeserve.co.uk>; "Apolinário J Malawene"
> <ajmalawene01@hotmail.com>; "Bob and Karla Weldon"
<bobkarlaweldon@cs.com>;
> "Ed Francis" <cfranc@ilstu.edu>; "Tsamba--Alberto Julio"
> <ajtsamba@zebra.uem.mz>; <stoves@crest.org>
> Sent: Tuesday, November 06, 2001 5:36 PM
> Subject: Re: More on best stoves
>
>
> Ken,
>
> I like the idea (below). But because I must (currently) remove the
> gasifier unit in order to refill it, I can just as easily dump it into a
> container such as you suggest. Also, I am concerned about leaking
primary
> air into the gasification chamber.
>
> However, my earlier experiences (perhaps with air leaks) was that the
> charcoal did NOT extinguish (starved of oxygen). Do you have info to
> share about how to smother the hot charcoal? If air leaks in from the
top
> (sealed-bottom cans are easy to obtain), with the charcoal extinguish
> itself?
>
> Paul
>
> At 06:21 PM 11/6/01 +0000, you wrote:
> >Paul and stove listers,
> >
> >Might I suggest having a charcoal storage container below your gasifier.
> >This can be just another tin can but with a sliding or "butterfly valve"
> >rotating lid. When the gasification is complete, the bottom of the
> >gasifying can is slid or rotated and the charcoal falls into an airtight
> >container and smoulders until the oxygen is consumed - but still
> >contributes some heat (for a while as it extinguishes), upwards into the
> >gasification zone.
> >
> >The container should be sized to allow charcoal from 2 or more burns to
be
> >stored.
> >
> >In this way you do not lose the stored heat or end up with wet quenched
> >charcoal.
> >
> >Ken Boak
> >
> >
> >_______________________________________________________________________
> >Never pay another Internet phone bill!
> >Freeserve AnyTime, for all the Internet access you want, day and night,
> >only £12.99 per month.
> >Sign-up at http://www.freeserve.com/time/anytime
>
> Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>
>
>
>
>
> -
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From psanders at ilstu.edu Wed Nov 7 10:10:11 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:16 2004
Subject: IDD & Charcoal(was Re: More on best stoves)
In-Reply-To: <4.3.1.2.20011106102925.01a6ddd0@mail.ilstu.edu>
Message-ID: <4.3.1.2.20011107090755.01a57330@mail.ilstu.edu>

Good comment, but I am thinking of NOT using riser sleeves or other
insulation unless it is literally dirt-cheap in Developing countries.

Also, earlier comments from others commented on the need to place the
burning charcoal quite close to the object to be heated or cooked. But in
the gasifier, there is considerable height added by the burner chamber
(which is not needed if burning the charcoal) and by the gasifier lower
unit itself.

So I continue with my question of how to consume the produced charcoal
separately from the gasifier stove. More help please.

To ELK: you make char and then you must cool it in order to process it
into your Chardust briquettes. Any suggestions?

Paul

At 12:28 AM 11/7/01 -0600, Harmon Seaver wrote:
> I understand the desire to save the charcoal (for resale or later
>use) in some sectors, but for my own uses, I'm thinking it would be best
>if it all burned. Paul mentioned this possibly being hard on the stove,
>but I'd assume not if you're using riser sleeves or some other ceramic
>insulation. Are there any other drawbacks or difficulties in allowing
>the charcoal to just burn?
>
>--
>Harmon Seaver, MLIS
>CyberShamanix
>Work 920-203-9633
>Home 920-233-5820
>hseaver@cybershamanix.com
>http://www.cybershamanix.com/resume.html
>
>
>
>-
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>-
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>
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From psanders at ilstu.edu Wed Nov 7 10:48:45 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:16 2004
Subject: IDD & Charcoal(was Re: More on best stoves)
In-Reply-To: <3BE8D483.3CBF04FC@cybershamanix.com>
Message-ID: <4.3.1.2.20011107094128.00c18b00@mail.ilstu.edu>

Stovers,

I agree with AJH's comments about the need (desirability) of removing the
char from the gasifier unit before the temperature rises when the char
starts its "burn".

>AJH also wrote:
>My solution is to recycle the char, minus any fines and ash, with the
>next fuel load. With small twigs char production does not seem to
>exceed 25% of the original mass, so any char mixed homogeneously with
>the fuel load exhibits a half life in the fuel cycle, though I have
>not tried this over more than a few burns.

Paul asks:

Does the char need to be cool before mixing? If it is hot it could cause
gasification lower in the fuel load instead of at the top and then working
downwards.

I assume that simply dumping the hot char on top of the next fuel load
would accomplish nothing desirable, but would simply act like a deeper fuel
load, of which the top part has already had its pyrolysis completed and
would only serve to slow (undesirable) the upward movement of the gases
from below.

ALSO, is the resultant char from a gasifier stove equivalent in "caloric
reserve" (my made-up term) to char that is produced by other methods, such
as what ELK is using or what AD Karve is initiating with cane leaves in India?

Char is char is char is char ?????? Or is it NOT the same?

Paul

At 10:00 AM 11/7/01 +0000, AJH wrote:
>On Wed, 07 Nov 2001 00:28:32 -0600, Harmon Seaver
><hseaver@cybershamanix.com> wrote:
>
> > I understand the desire to save the charcoal (for resale or later
> >use) in some sectors, but for my own uses, I'm thinking it would be best
> >if it all burned.
>
>Unless the household has use for charcoal burning as well I wonder if
>there is any likelihood of trading these small quantities. I think a
>number of us consider that the char residue is not a major attribute
>in domestic cooking, there is a possible exception which Alex and I
>discussed on list, it attracted attention in an FAO newsletter at the
>time, that was the possibility of a communal gasifier-ic engine using
>the char to perform pumping/grinding/generation tasks. The theory
>being that a simple CO generator is easier to run than an full blown
>downdraft gasifier, though power is much reduced.
>
> > Paul mentioned this possibly being hard on the stove,
> >but I'd assume not if you're using riser sleeves or some other ceramic
> >insulation. Are there any other drawbacks or difficulties in allowing
> >the charcoal to just burn?
>
>Lots of problems, the first is that the idd stove produces its flame
>as a diffuse combination of pyrolysis products. Most of the gases for
>this flame come from the secondary air slit and the fuel gas is of a
>high cv. This is because the primary air requirement is low so the
>offgas is little diluted by the primary combustion products. The fuel
>holder is the primary combustion zone (where flaming pyrolysis occurs)
>and temperatures need only be sufficient to enable pyrolysis, hence a
>simple steel container will suffice.
>
>Once the flaming pyrolysis front reaches the bottom of the stove then
>charcoal burns, with low primary air velocities it burns completely to
>CO2 and a lot of heat is released at the bottom of the stove, the only
>flue gas is CO2 (plus combustion products of higher volatiles left in
>the char) and it has the whole of the char column plus secondary air
>entrainment plus secondary air combustion space to lose heat from, it
>will not contribute a lot to cooking.
>
>To turn this into an updraft gasifier you need to increase primary
>airflow enough to form a deep hot bed (Tom Reed estimates it must be
>20 article diameters deep) that will react the CO2 initially produced
>to CO, the CO then being burned with secondary air as in the idd mode.
>It is unlikely this can be done with natural draught in the absence of
>a long chimney (which is precluded by the need to sit a pot on the
>outlet). Also the CO generating region is >700C and quickly eats
>through a steel container, though a simple flower pot in the bottom
>will increase life.
>
>My solution is to recycle the char, minus any fines and ash, with the
>next fuel load. With small twigs char production does not seem to
>exceed 25% of the original mass, so any char mixed homogeneously with
>the fuel load exhibits a half life in the fuel cycle, though I have
>not tried this over more than a few burns.
>
>AJH
>
>
>-
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From psanders at ilstu.edu Wed Nov 7 11:08:32 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:16 2004
Subject: Charcoal - To burn or produce?
In-Reply-To: <4.3.1.2.20011106102925.01a6ddd0@mail.ilstu.edu>
Message-ID: <4.3.1.2.20011107095936.00c186b0@mail.ilstu.edu>

Tom and all,

In your message (below for those who did not see it), I assume that you are
NOT advocating or seeing advantages of using wetter fuel. If the fuel is
damp (or too damp for the gasifier operation), I would prefer to do some
drying of future fuel separately from the gasifier for cooking. Drying
could be done with some of the waste heat from the gasifier stove usage, OR
maybe done by using the resultant char, about which we are discussing
possible uses.

Given the LOW amount of primary air needed for gasification of dry fuel,
and assuming that the gasifier (lower) unit is not leaking in extra air,
when the gasification is completed, the amount of gases then is greatly
diminished, the flame in the upper (burner) chamber goes out, there is some
resultant smoking (undesirable, and potentially dangerous to health). BUT
that is a clear signal that it is time to remove the char to whatever other
location has been chosen. If the meal is almost ready (just to simmer, or
just to keep it hot), then the char in another container could do the
needed job, and the gasifier is finished for that meal cooking or heating job.

This (above) leads me to continue to see value in a very simple lower
(gasifier) chamber with very little entry of primary air (controls are
being discussed, but it will be focused on the small volume of air needed,
not on the 6 to 1 increase needed IF the charcoals were to be burned in the
gasifer unit.)

Hey, keep talking!!!! This is all VERY HELPFUL !!!!!

Paul

At 05:45 AM 11/7/01 -0700, Thomas Reed wrote:
>Dear Stovers All:
>
>When I first operated an inverted downdraft gasifier-stove in 1985 I was
>delighted how easily it made a combustible gas - but not happy about
>charcoal production (~20% here in Dry Denver).
>
>When Ron Larson contacted me in 1995 to ask if I knew how to use the
>volatiles from charcoal making I was happy to say that I was working on
>stoves that did both. Ron convinced me that the charcoal would be a
>positive by-product in some parts of the world where charcoal is used in the
>cities. Two years later we published our paper on natural draft WoodGas
>stoves.
>
>Nevertheless, from the viewpoint of many cooks, charcoal production was a
>nuisance, since up to 1/3 of the fuel value is in the charcoal.
> ~~~~~
>The problem is that biomass is really two fuels:
>
>1) the volatiles that are released between 300 and 400 C
>
>2) the charcoal that remains afterward.
>
>I have found two solutions to this.
>
>1) With proper control of primary (gasification) air and combustion air, one
>can use VERY little primary air to gasify dry fuel (< 1/1 Air/fuel ratio),
>moderate primary air for wet fuels (up to ~ 30%moisture, ~3/1 A/F) and lots
>of air (6/1 A/F)to gasify charcoal to a beautifully burning CO/H2 flame.
>This requires some attention from the cook to either change the ratio when
>the volatiles have burned or add more fuel on top of the hot charcoal
>(approximately 10 g/min to prevent big flare).
>
>2) By burning wetter and wetter fuels the problem disappears because the
>charcoal needs to burn to dry the fuel to permit flame propagation.
>
>There may be other ways to consume biomass as if it were a single fuel and I
>am investigating them.
>
>Onward....... TOM REED BEF
>
>
>
> Dr. Thomas Reed
> The Biomass Energy Foundation
> 1810 Smith Rd., Golden, CO 80401
>303 278 0558;
>tombreed@home.com; www.woodgas.com
>----- Original Message -----
>From: "Harmon Seaver" <hseaver@cybershamanix.com>
>To: <stoves@crest.org>
>Sent: Tuesday, November 06, 2001 11:28 PM
>Subject: IDD & Charcoal(was Re: More on best stoves)
>
>
> > I understand the desire to save the charcoal (for resale or later
> > use) in some sectors, but for my own uses, I'm thinking it would be best
> > if it all burned. Paul mentioned this possibly being hard on the stove,
> > but I'd assume not if you're using riser sleeves or some other ceramic
> > insulation. Are there any other drawbacks or difficulties in allowing
> > the charcoal to just burn?
> >
> > --
> > Harmon Seaver, MLIS
> > CyberShamanix
> > Work 920-203-9633
> > Home 920-233-5820
> > hseaver@cybershamanix.com
> > http://www.cybershamanix.com/resume.html
> >
> >
> >
> > -
> > Stoves List Archives and Website:
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> >
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> >
> > For information about CHAMBERS STOVES
> > http://www.ikweb.com/enuff/public_html/Chamber.htm
> >

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From psanders at ilstu.edu Wed Nov 7 11:21:34 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:16 2004
Subject: Charcoal post combustion..
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <4.3.1.2.20011107101508.00c1f750@mail.ilstu.edu>

I can relate to Tom's experience about difficulty extinguishing
charcoal. (makes me think of coal mine fires that burn for centuries, but
that probably has additional factors that I do not want to explore.)

I have been quenching (dump into a bucket of water). Waterlogged
charcoal. Not good. But I could probably "air dry" the charcoal or "sun
dry" it or even dry it on a pan that is heated by the fire that I next use,
the same day or weeks later.

But Tom suggests spraying, which I like better than trying to get airtight
containers for cooks in the Third World.

Might that be "spread and spray"?

or "spread, spray, stir, spray" a "4-S" process?

Boy scouts use the "you can touch it with your bare hand" test for
extinguishing camp fires.

Paul

At 06:46 AM 11/7/01 -0700, Thomas Reed wrote:
>Dear Kevin and all:
>
>It is VERY difficult to extinguish charcoal because of the effect Kevin so
>well discussed below.
>
>I have had "extinguished stoves" be still warm a day later.
>
>Also, leaks can generate CO - deadly if you get enough.
>
>So make airtight extinction really tight - or spray on water!
>
>TOM
> Dr. Thomas Reed
> The Biomass Energy Foundation
> 1810 Smith Rd., Golden, CO 80401
>303 278 0558;
>tombreed@home.com; www.woodgas.com
>----- Original Message -----
>From: "Kevin Chisholm" <kchishol@fox.nstn.ca>
>To: <kenboak@stirlingservice.freeserve.co.uk>; "Apolinário J Malawene"
><ajmalawene01@hotmail.com>; "Bob and Karla Weldon" <bobkarlaweldon@cs.com>;
>"Ed Francis" <cfranc@ilstu.edu>; "Tsamba--Alberto Julio"
><ajtsamba@zebra.uem.mz>; <stoves@crest.org>; "Paul S. Anderson"
><psanders@ilstu.edu>
>Sent: Tuesday, November 06, 2001 7:57 PM
>Subject: Re: More on best stoves
>
>
> > Dear Paul
> >
> > Charcoal will extinguish itself in short order in an airtight container.
>If
> > it doesn't extinguish, then it is because air is leaking in.
> >
> > Air leaking in from the top wil "fuel the fire." Fundamentally, the
>charcoal
> > cannot sustain combustion without oxygen.
> >
> > Consider if there was a single hole, 1/4" diameter, anywhere, in an
> > otherwise airtight container. As the container cooled, it would initially
> > draw air in, but then combustion and heating would occur, and the products
> > of combustion would be expelled. AS they are being expelled, no air is
> > entering, and the charcoal tends to cool. Then the process repeats itself.
> >
> > Consider if ther were two 1/4" holesanywhere in the container, so long as
> > they were at different elevations; then a "stack effect" would be created.
> >
> > Hope this helps visualize the problem.
> >
> > Kevin Chisholm
> > ----- Original Message -----
> > From: "Paul S. Anderson" <psanders@ilstu.edu>
> > To: <kenboak@stirlingservice.freeserve.co.uk>; "Apolinário J Malawene"
> > <ajmalawene01@hotmail.com>; "Bob and Karla Weldon"
><bobkarlaweldon@cs.com>;
> > "Ed Francis" <cfranc@ilstu.edu>; "Tsamba--Alberto Julio"
> > <ajtsamba@zebra.uem.mz>; <stoves@crest.org>
> > Sent: Tuesday, November 06, 2001 5:36 PM
> > Subject: Re: More on best stoves
> >
> >
> > Ken,
> >
> > I like the idea (below). But because I must (currently) remove the
> > gasifier unit in order to refill it, I can just as easily dump it into a
> > container such as you suggest. Also, I am concerned about leaking
>primary
> > air into the gasification chamber.
> >
> > However, my earlier experiences (perhaps with air leaks) was that the
> > charcoal did NOT extinguish (starved of oxygen). Do you have info to
> > share about how to smother the hot charcoal? If air leaks in from the
>top
> > (sealed-bottom cans are easy to obtain), with the charcoal extinguish
> > itself?
> >
> > Paul
> >
> > At 06:21 PM 11/6/01 +0000, you wrote:
> > >Paul and stove listers,
> > >
> > >Might I suggest having a charcoal storage container below your gasifier.
> > >This can be just another tin can but with a sliding or "butterfly valve"
> > >rotating lid. When the gasification is complete, the bottom of the
> > >gasifying can is slid or rotated and the charcoal falls into an airtight
> > >container and smoulders until the oxygen is consumed - but still
> > >contributes some heat (for a while as it extinguishes), upwards into the
> > >gasification zone.
> > >
> > >The container should be sized to allow charcoal from 2 or more burns to
>be
> > >stored.
> > >
> > >In this way you do not lose the stored heat or end up with wet quenched
> > >charcoal.
> > >
> > >Ken Boak
> > >
> > >
> > >_______________________________________________________________________
> > >Never pay another Internet phone bill!
> > >Freeserve AnyTime, for all the Internet access you want, day and night,
> > >only £12.99 per month.
> > >Sign-up at http://www.freeserve.com/time/anytime
> >
> > Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> > Dept of Geography - Geology (Box 4400), Illinois State University
> > Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> > E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
> >
> >
> >
> >
> >
> > -
> > Stoves List Archives and Website:
> > http://www.crest.org/discussion/stoves/current/
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> >
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> >
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> > -
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> > http://www.fsec.ucf.edu/bioam/
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> > http://solstice.crest.org/renewables/biomass-info/carbon.shtml
> >
> > For information about CHAMBERS STOVES
> > http://www.ikweb.com/enuff/public_html/Chamber.htm
> >
> >
>
>
>-
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>
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From hseaver at cybershamanix.com Wed Nov 7 11:57:50 2001
From: hseaver at cybershamanix.com (Harmon Seaver)
Date: Tue Aug 31 21:37:16 2004
Subject: Charcoal post combustion..
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <3BE967EA.BEE4DA09@cybershamanix.com>

Seems to me I recall reading warnings about damp charcoal and
auto-combustion -- can't remember what the exact mechanisim involved was. Also, I
think, there were warnings about the dangers of explosions????

"Paul S. Anderson" wrote:

> I can relate to Tom's experience about difficulty extinguishing
> charcoal. (makes me think of coal mine fires that burn for centuries, but
> that probably has additional factors that I do not want to explore.)
>
> I have been quenching (dump into a bucket of water). Waterlogged
> charcoal. Not good. But I could probably "air dry" the charcoal or "sun
> dry" it or even dry it on a pan that is heated by the fire that I next use,
> the same day or weeks later.
>
> But Tom suggests spraying, which I like better than trying to get airtight
> containers for cooks in the Third World.
>
> Might that be "spread and spray"?
>
> or "spread, spray, stir, spray" a "4-S" process?
>
> Boy scouts use the "you can touch it with your bare hand" test for
> extinguishing camp fires.

--
Harmon Seaver, MLIS
CyberShamanix
Work 920-203-9633
Home 920-233-5820
hseaver@cybershamanix.com
http://www.cybershamanix.com/resume.html

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From andrew.heggie at dtn.ntl.com Wed Nov 7 14:04:12 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:16 2004
Subject: Charcoal post combustion..
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <pttiutoq54849r2monnqstlur02bgf9tp9@4ax.com>

On Wed, 07 Nov 2001 10:25:49 -0600, "Paul S. Anderson"
<psanders@ilstu.edu> wrote:

>I have been quenching (dump into a bucket of water). Waterlogged
>charcoal. Not good. But I could probably "air dry" the charcoal or "sun
>dry" it or even dry it on a pan that is heated by the fire that I next use,
>the same day or weeks later.

I do not consider this a bad option, charcoal is porous so dries quite
quickly, the dunking also removes ash from the surface. You need to be
quite quick as the charcoal will sink with the ash once it saturates,
I use a kitchen sieve to retrieve the char and allow the ash and char
fines to sink.
>
>But Tom suggests spraying, which I like better than trying to get airtight
>containers for cooks in the Third World.

On the large scale I have found spraying difficult, if you miss a bit
the first think you see is a white patch of ash spreading over the
black surface.
AJH

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From andrew.heggie at dtn.ntl.com Wed Nov 7 14:04:52 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:17 2004
Subject: IDD & Charcoal(was Re: More on best stoves)
In-Reply-To: <3BE8D483.3CBF04FC@cybershamanix.com>
Message-ID: <v6uiutg08nn2dqdirl8apm247khdc5l7sv@4ax.com>

On Wed, 07 Nov 2001 09:53:35 -0600, "Paul S. Anderson"
<psanders@ilstu.edu> wrote:

>Does the char need to be cool before mixing? If it is hot it could cause
>gasification lower in the fuel load instead of at the top and then working
>downwards.

Absolutely, if the char is hot it will start burning in the primary
air, turning the fuel above it into a smoky bonfire. Freshly made
charcoal ignites very easily, I have had it ignite in a drying oven
presumably from the radiant energy from the heating element, after all
charcoal is nearly a black body, remember char does not need a flame
to ignite it. Anybody know offhand what the spontaneous temperature
for combustion of char is? I seem to recall it is 1200C for diamond to
graphitise.
>
>I assume that simply dumping the hot char on top of the next fuel load
>would accomplish nothing desirable, but would simply act like a deeper fuel
>load, of which the top part has already had its pyrolysis completed and
>would only serve to slow (undesirable) the upward movement of the gases
>from below.

Correct, the area above the flaming pyrolysis zone is essentially
inert.

>ALSO, is the resultant char from a gasifier stove equivalent in "caloric
>reserve" (my made-up term) to char that is produced by other methods, such
>as what ELK is using or what AD Karve is initiating with cane leaves in India?
>
>Char is char is char is char ?????? Or is it NOT the same?

Not necessarily the same, pure carbon char as used in silicon
production is probably nearly pure carbon and ash, it is cooked at
high temperature. The char from the idd will depend on the temperature
reached but will have those volatiles in it that have not been heated
to vapour in the primary chamber, it will contain the ash still in the
char matrix as well as ash from char consumed to CO2 in the process.

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From andrew.heggie at dtn.ntl.com Wed Nov 7 14:05:25 2001
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:17 2004
Subject: Charcoal post combustion..
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <5i0jut00pb81ml00kgcgq6d2h2a8adcd6l@4ax.com>

On Wed, 07 Nov 2001 10:57:22 -0600, Harmon Seaver
<hseaver@cybershamanix.com> wrote:

> Seems to me I recall reading warnings about damp charcoal and
>auto-combustion -- can't remember what the exact mechanisim involved was. Also, I
>think, there were warnings about the dangers of explosions????

I would be very interested to hear more of this. As a seasonal
anecdote after Guido's arrest the remainder of the plotters retreated
with one barrel of powder, for the muskets, to a stately home. Once
there they found the powder damp, so they spread it in front of the
open fire.

It subsequently ignited and injured them all, soon after they were
captured.

Now black powder is a mixture of char, potassium nitrate and sulphur.
I would not expect any volatiles to be given off to cause a flash
over. I imagine they were mindful of sparks, so could the black powder
have reached its spontaneous ignition temperature from the radiation
of the flames?

AJH

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From hseaver at cybershamanix.com Wed Nov 7 22:25:37 2001
From: hseaver at cybershamanix.com (Harmon Seaver)
Date: Tue Aug 31 21:37:17 2004
Subject: Charcoal post combustion..
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <3BE9FB08.AC09B15E@cybershamanix.com>

AJH wrote:

> On Wed, 07 Nov 2001 10:57:22 -0600, Harmon Seaver
> <hseaver@cybershamanix.com> wrote:
>
> > Seems to me I recall reading warnings about damp charcoal and
> >auto-combustion -- can't remember what the exact mechanisim involved was. Also, I
> >think, there were warnings about the dangers of explosions????
>
> I would be very interested to hear more of this.

I've been looking thru my 1961 edition of the USFS Report # 2213, "Charcoal:
Production, Marketing, and Use" which I got and read thoroughly many years ago when
seriously contemplating a career as a charcoaler. And which, I would have thought,
would have been the source of that idea, but now I'm not sure. It has a lot to say
about charcoal explosions, but those seem to be within kilns. It does mention,
however:
"Although spontaneous combustion (self ignition by generation of heat through
chemical action within the charcoal) is always a possibility..." and goes on to speak
of the dangers of fires from not-quite-extinguished coal.
That passage, however, does bring the argument a bit more into focus -- that
there is a distinct correlation between moisture, pressure, and heating in supposedly
"dry" charcoal.

So, just doing a google on "spontaneous combustion" and charcoal, finds:

> Some of the materials which have a high tendency to heat are linseed oil which is commonly used in
> furniture refinishing, fish meal, fish oil, alfalfa meal, cod liver oil, corn meal feeds, oiled fabrics, oiled
> rags, peanuts, varnished fabrics, and charcoal.
>
> Large coal piles must be carefully prepared to prevent heating of the material. Large industrial users
> such as hydro generating plants and similar facilities, monitor the moisture content, and compaction, of
> their coal piles very closely to ensure that spontaneous heating and ignition does not occur.
>

and from the NY fire dept.:

> Keep damp or wet coals in a well ventilated area. During the drying process, spontaneous
> combustion can occur in confined areas.
>

and from http://www.barbecueing.com/html/safety.html:

> When cooking is over, soak the coals so to prevent their
> re-ignition. Dispose of charcoal in a metal container with a tight
> fitting lid. Never keep damp or wet charcoal in an unventilated
> area due to the dangers of spontaneous combustion that can
> result from drying.
>

and from http://www.co.arlington.va.us/fire/cookout.htm

> Keep damp or wet coals in a well ventilated area. During the drying process, spontaneous
> combustion can occur in confined areas. If a bag of charcoal gets wet, leave it outside, away
> from combustibles.
>

and
http://www.travis.af.mil/news/tailwindonline/stories_2001/august/20010824_03.htmBy

60th Civil Engineer Squadron
Fire Protection Flight

> - Dampness in charcoal can cause spontaneous combustion. Therefore, charcoal should be stored in a dry place
> to protect from dampness.
>

Well, there's about 562 hits on this subject.

Mind you, none of these, including the aforementioned USFS book, is anything I'd
consider as gospel, and all this might stem from the same contaminated source. But it
definitely makes me nervous ...

--
Harmon Seaver, MLIS
CyberShamanix
Work 920-203-9633
Home 920-233-5820
hseaver@cybershamanix.com
http://www.cybershamanix.com/resume.html

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From hseaver at cybershamanix.com Wed Nov 7 22:48:49 2001
From: hseaver at cybershamanix.com (Harmon Seaver)
Date: Tue Aug 31 21:37:17 2004
Subject: Stoves, hmmm!
Message-ID: <3BEA007F.35E8EA2C@cybershamanix.com>

Lit off my first stove tonight. Not exactly what I'd call a roaring
success, but it was interesting. I took a coffee can (6" x 6" more or
less) and punched two opposing holes in it's sides at the bottom. Then I
put in a clay flower pot, one of my wife's "bulb pots" which has not
just the normal center hole, but also 4 smaller holes, actually, slots,
around the edge, in the can for a fire chamber. I filled this with wood
pellets, then topped it with a 24" length of 6" stove pipe, which had
1/4" holes drilled 1" apart all around about 15" from what would be the
top of the can & pot.
I tried to light the pellets by lighting a ball of crunched
newspaper and dropping it in, but that didn't seem too effective, so
finally took off the stove pipe, and used a propane torch, then
reinserted the stove pipe. Once assured the pellets were indeed burning,
I then put another stove pipe, 8 inch, over the whole thing to add
insulation.
The pellets did burn fairly smoke free for over 1/2 hour, then I
went in for awhile, to find that at one hour after lighting, there was a
fairly heavy smoke coming out. Tried to light that, to no avail. Later I
see a nice pot of charcoal, mostly out. I don't think I was ever getting
a good secondary combustion (no flame at the top) but I do see a "line"
on the inside of the pipe at the level of the secondary air holes.
Tomorrow I'll try a load of twigs instead of the pellets, and I'll
insulate the area between the 6" and 8" stove pipe. Also maybe will try
more secondary air holes lower on the pipe.
I just picked up 3 nice little 15 gallon steel drums (13"x25") and
3 30 gallon drums (18.5"x29") to experiment with -- wish I could find
something like a 10 gallon. But I'll burn up some tin cans before I
start on those.

--
Harmon Seaver, MLIS
CyberShamanix
Work 920-203-9633
Home 920-233-5820
hseaver@cybershamanix.com
http://www.cybershamanix.com/resume.html

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From kchishol at fox.nstn.ca Wed Nov 7 22:56:45 2001
From: kchishol at fox.nstn.ca (Kevin Chisholm)
Date: Tue Aug 31 21:37:17 2004
Subject: Charcoal post combustion..
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <005a01c16808$f3ab4740$0d19059a@kevin>

Dear Harmon

I recall from a book on charcoal, that it can be pyrophoric, when made under
the right conditions: retorted in a vacuum.

This suggests that the specific manufacturing process may have a bearing on
the tendancy of atmospherically produced charcoals to combust spontaneously.

Kindest regards,

Kevin Chisholm

----- Original Message -----
From: "Harmon Seaver" <hseaver@cybershamanix.com>
To: "AJH" <andrew.heggie@dtn.ntl.com>
Cc: <stoves@crest.org>
Sent: Wednesday, November 07, 2001 11:26 PM
Subject: Re: Charcoal post combustion..

> AJH wrote:
>
> > On Wed, 07 Nov 2001 10:57:22 -0600, Harmon Seaver
> > <hseaver@cybershamanix.com> wrote:
> >
> > > Seems to me I recall reading warnings about damp charcoal and
> > >auto-combustion -- can't remember what the exact mechanisim involved
was. Also, I
> > >think, there were warnings about the dangers of explosions????
> >
> > I would be very interested to hear more of this.
>
> I've been looking thru my 1961 edition of the USFS Report # 2213,
"Charcoal:
> Production, Marketing, and Use" which I got and read thoroughly many years
ago when
> seriously contemplating a career as a charcoaler. And which, I would have
thought,
> would have been the source of that idea, but now I'm not sure. It has a
lot to say
> about charcoal explosions, but those seem to be within kilns. It does
mention,
> however:
> "Although spontaneous combustion (self ignition by generation of heat
through
> chemical action within the charcoal) is always a possibility..." and goes
on to speak
> of the dangers of fires from not-quite-extinguished coal.
> That passage, however, does bring the argument a bit more into
focus -- that
> there is a distinct correlation between moisture, pressure, and heating in
supposedly
> "dry" charcoal.
>
> So, just doing a google on "spontaneous combustion" and charcoal, finds:
>
> > Some of the materials which have a high tendency to heat are linseed oil
which is commonly used in
> > furniture refinishing, fish meal, fish oil, alfalfa meal, cod liver oil,
corn meal feeds, oiled fabrics, oiled
> > rags, peanuts, varnished fabrics, and charcoal.
> >
> > Large coal piles must be carefully prepared to prevent heating of the
material. Large industrial users
> > such as hydro generating plants and similar facilities, monitor the
moisture content, and compaction, of
> > their coal piles very closely to ensure that spontaneous heating and
ignition does not occur.
> >
>
> and from the NY fire dept.:
>
> > Keep damp or wet coals in a well ventilated area. During the drying
process, spontaneous
> > combustion can occur in confined
areas.
> >
>
> and from http://www.barbecueing.com/html/safety.html:
>
> > When cooking is over, soak the coals so to prevent their
> > re-ignition. Dispose of charcoal in a
metal container with a tight
> > fitting lid. Never keep damp or wet
charcoal in an unventilated
> > area due to the dangers of spontaneous
combustion that can
> > result from drying.
> >
>
> and from http://www.co.arlington.va.us/fire/cookout.htm
>
> > Keep damp or wet coals in a well ventilated area. During the drying
process, spontaneous
> > combustion can occur in confined areas. If a bag of
charcoal gets wet, leave it outside, away
> > from combustibles.
> >
>
> and
>
http://www.travis.af.mil/news/tailwindonline/stories_2001/august/20010824_03
.htmBy
>
> 60th Civil Engineer Squadron
> Fire Protection Flight
>
> > - Dampness in charcoal can cause spontaneous combustion. Therefore,
charcoal should be stored in a dry place
> > to protect from dampness.
> >
>
> Well, there's about 562 hits on this subject.
>
> Mind you, none of these, including the aforementioned USFS book, is
anything I'd
> consider as gospel, and all this might stem from the same contaminated
source. But it
> definitely makes me nervous ...
>
>
> --
> Harmon Seaver, MLIS
> CyberShamanix
> Work 920-203-9633
> Home 920-233-5820
> hseaver@cybershamanix.com
> http://www.cybershamanix.com/resume.html
>
>
>
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From elk at wananchi.com Thu Nov 8 03:24:50 2001
From: elk at wananchi.com (elk)
Date: Tue Aug 31 21:37:17 2004
Subject: Extinguishing charcoal
In-Reply-To: <4.3.1.2.20011106102925.01a6ddd0@mail.ilstu.edu>
Message-ID: <009801c1682f$1cb8a8a0$0100007f@default>

For small quantities we leave overnight in sealed 200 l. drums. Don't forget
the pinprick hole to prevent implosion on cooling.

I deal with charred particulate matter only- please note.

For larger amounts of charred material we sprinkle water and turn
occasionally. A night watchman is an essential minder...... takes at least
24 hours to ensure quenching. Materials differ- coffee husk is very easily
quenched. Same for rice husk. Sawdust is middling-difficult and bagasse is
difficult. Sisal waste & coconut husk fibre is nigh-on impossible to quench
short of turning it into a black mud.

We try to keep moisture contents in the quenched material below 30% or we
have to waste time & effort pre-drying before the addition of binder (which
are added in a slurry) and extrusion.

rgds;

--------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi Kenya

----- Original Message -----
From: "Paul S. Anderson" <psanders@ilstu.edu>
To: "Harmon Seaver" <hseaver@cybershamanix.com>; <stoves@crest.org>
Sent: Wednesday, November 07, 2001 6:14 PM
Subject: Re: IDD & Charcoal(was Re: More on best stoves)

> Good comment, but I am thinking of NOT using riser sleeves or other
> insulation unless it is literally dirt-cheap in Developing countries.
>
> Also, earlier comments from others commented on the need to place the
> burning charcoal quite close to the object to be heated or cooked. But in
> the gasifier, there is considerable height added by the burner chamber
> (which is not needed if burning the charcoal) and by the gasifier lower
> unit itself.
>
> So I continue with my question of how to consume the produced charcoal
> separately from the gasifier stove. More help please.
>
> To ELK: you make char and then you must cool it in order to process it
> into your Chardust briquettes. Any suggestions?
>
> Paul
>
> At 12:28 AM 11/7/01 -0600, Harmon Seaver wrote:
> > I understand the desire to save the charcoal (for resale or later
> >use) in some sectors, but for my own uses, I'm thinking it would be best
> >if it all burned. Paul mentioned this possibly being hard on the stove,
> >but I'd assume not if you're using riser sleeves or some other ceramic
> >insulation. Are there any other drawbacks or difficulties in allowing
> >the charcoal to just burn?
> >
> >--
> >Harmon Seaver, MLIS
> >CyberShamanix
> >Work 920-203-9633
> >Home 920-233-5820
> >hseaver@cybershamanix.com
> >http://www.cybershamanix.com/resume.html
> >
> >
> >
> >-
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> >
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>
> Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
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From Carefreeland at aol.com Thu Nov 8 12:50:50 2001
From: Carefreeland at aol.com (Carefreeland@aol.com)
Date: Tue Aug 31 21:37:17 2004
Subject: spontanous charcoal combustion
Message-ID: <4e.15b575a.291c1fd3@aol.com>

Colliers,
It seems we are trying to figure out how a pile of stored charcoal can
burst into flames. First, embers can stay alive in charcoal for long periods
of time because the insulation factors involved. This is even more pronounced
in coal mine fires. Even a small amount of air will continue the burn. Hot
gases escaping draw fresh air in from cracks and water steam reforms the coal
at high temperatures.
The presents of water can help or hurt, depending on several factors some
of which I am not sure about when or if. First, biochemical decomposition of
the hydrocarbon and nitrogen impurities. The lower the temperature that the
char is produced at the more hydrocarbon residue that can stay. Biochemical
decomposition such as in a compost pile can cause heat build up until
probably the hydrocarbons ignite first, most likely in gas form then igniting
the charcoal.
There may be some sort of ignition taking place from chemical reactions
such as the way linseed oil ignites in oily rags. I can't help but suspect
that nitrogen is involved in there somewhere, know of no evidence to prove
this. If anybody can find the exact breakdown sequence of linseed oil this
would provide a valuable insight.
Lastly, solar ignition from solar heat buildup in a small hole could
possibly reach ignition points.
Let me shed some light on another viewpoint. I have done extensive
experiments with ignition of genuine black powder. With every case I looked
at it was always the sulfur that gasified and then ignited first, before the
charcoal. This leads me to believe it is hydrocarbon impurities in the char
lowering the ignition point dangerously. The higher temp retort char I have
done ignition tests on seems to have a high ignition point.
The highest sustained temp during the charring that the whole charge was
exposed to, would determine the volatility point of any hydrocarbon present.
In other wards say you have part of the charge you are working with only
reach F 300. When the char achieves that temp again it will again start to
release the hydrocarbon not yet released. The gas being released is the
culprit. Pure carbon has a very high ignition temp.
Now a static spark which can be very high temp, can ignite fine charcoal
dust. For this reason a bit of moisture is recommended to keep the static
charges down. In dry climates this can be the biggest hazard. When I first
learned the art of crushing black powder cakes which is the most dangerous
part, I would breath on the powder to moisten the air in the mortar and
pestle. Then I would not use any procedure producing hot friction points.
Fireworks factories use grounded touch pads to dissipate static
electricity. They also commonly use controlled humidity to dissipate the same
thing.
If one mixes potassium chlorate with sulfur, a scrape in the mortar by
the pestle can easily detonate the charge with frightening consequences. A
charge the size of your fingernail clipping can be louder than a firecracker.
(This is the bang in firecrackers today anyhow. The aluminum powder
provides the flash) If you use just charcoal alone with the potassium
chlorate, that reaction will not happen. The chlorate is releasing it's
oxygen from the heat of friction, but the ignition temp of the char is too
high, even in the presents of pure oxygen.
This again demonstrates how the lack of research into alternative fuels
can be a dangerous situation. The info gathered by positively identifying
the parameters of the reactions I just discussed would go a long way toward
fire safety in general. Why does it take a fatal explosion at a fireworks
factory to give the incentive to provide research data? Charcoal is the
oldest refined fuel, and yet has some of the most primitive research data
surrounding it. It was created first by forest fires.
Just use common sense, knowledge of the reactions, and store your char
outside, away from anything you wouldn't store a pile of coal next to, like a
chimney.
I have never heard of a truly wet pile of charcoal or coal igniting by
accident. In the State of Ohio, USA, both are stored outside, without covers
that could trap escaping gas. We handle a large percentage of the nations
coal supply. Producing, shipping, coking, and burning all included. Most of
the silos I see, are iron or brick and have drying/ventilation systems.
Careful and common sense, better than natural gas hu?
Daniel Dimiduk

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From hseaver at cybershamanix.com Thu Nov 8 19:30:06 2001
From: hseaver at cybershamanix.com (Harmon Seaver)
Date: Tue Aug 31 21:37:17 2004
Subject: Stoves, hmmm!
In-Reply-To: <3BEA007F.35E8EA2C@cybershamanix.com>
Message-ID: <3BEB2367.75A05FF1@cybershamanix.com>

Much greater success today! Taking another look at the Reed/Larson
stove, I realized I'd placed my secondary inlets much too high, so
drilled another series of holes around the 6" stovepipe just a couple
inches above where the stovepipe goes into the coffee can. Voila! A very
nice smokeless (except for a bit at startup) fire, very hot, lasts about
45 minutes, then turns to glowing coals, then out.
I'm still not seeing blue flames, but looking down into the stove
pipe, you clearly see a lot of secondary burning at the point of the air
inlets. Still big orange/yellow flames, but they look like gas jets
coming out of all those holes.
At this point, I'm thinking that maybe I'm not getting enough
primary air -- certainly I've seen absolutely no need to regulate
primary air, all I have now is two holes in the bottom (opposing sides)
of the coffee can punched with a church key. But maybe the holes in the
bottom of the flower pot aren't enough?

--
Harmon Seaver, MLIS
CyberShamanix
Work 920-203-9633
Home 920-233-5820
hseaver@cybershamanix.com
http://www.cybershamanix.com/resume.html

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From ronallarson at qwest.net Thu Nov 8 20:06:57 2001
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:17 2004
Subject: Stoves, hmmm!
In-Reply-To: <3BEA007F.35E8EA2C@cybershamanix.com>
Message-ID: <007e01c168bb$12363500$3ff66641@computer>

Harmon (cc stovers):

See notes below.

----- Original Message -----
From: Harmon Seaver <hseaver@cybershamanix.com>
To: stoves <stoves@crest.org>
Sent: Wednesday, November 07, 2001 8:49 PM
Subject: Stoves, hmmm!

> Lit off my first stove tonight. Not exactly what I'd call a roaring
> success, but it was interesting. I took a coffee can (6" x 6" more or
> less) and punched two opposing holes in it's sides at the bottom. Then I
> put in a clay flower pot, one of my wife's "bulb pots" which has not
> just the normal center hole, but also 4 smaller holes, actually, slots,
> around the edge, in the can for a fire chamber. I filled this with wood
> pellets, then topped it with a 24" length of 6" stove pipe, which had
> 1/4" holes drilled 1" apart all around about 15" from what would be the
> top of the can & pot.

RWL: 1. I would drop the 15" dimension to zero. Can't think of any reason
to have it this large. (But see below - things don't add up.)

2. The two "opposing holes" - what diameter? I would recommend making them
2-3 cm.

3. Not clear how you will be shutting these down for power output control.
I have used ceramic conical plugs (sometiimes just raw clay). With no plug
you might find the max output is more than you want.

4. Not sure that you will get enough air through the holes in the bulb pot.
Might
be worth trying without (but you will need some sort of grate to ensure air
can enter the fuel uniformly.

5. Can you describe the size of wood pellet you used?

6. It might be worth trying 2 or 3 inches height of pellets - to see the
differences.

> I tried to light the pellets by lighting a ball of crunched
> newspaper and dropping it in, but that didn't seem too effective, so
> finally took off the stove pipe, and used a propane torch, then
> reinserted the stove pipe. Once assured the pellets were indeed burning,
> I then put another stove pipe, 8 inch, over the whole thing to add
> insulation.

RWL: 7. I have found that crumpled newspaper leaves too much material
providing air resistance. I prefer (Ponderosa) pine needles. Try loose
cotton smeared with Vaseline.

> The pellets did burn fairly smoke free for over 1/2 hour, then I
> went in for awhile, to find that at one hour after lighting, there was a
> fairly heavy smoke coming out. Tried to light that, to no avail. Later I
> see a nice pot of charcoal, mostly out. I don't think I was ever getting
> a good secondary combustion (no flame at the top) but I do see a "line"
> on the inside of the pipe at the level of the secondary air holes.

RWL: 8. Getting the heavy smoke is common when pyrolysis is complete. At
that point, you have to open the primary air ports and start combusting the
bottom layer of charcoal, if that is your intent. You just didn't have
enough total air entering at the bottom. But my contention is that you
wouldn't have gotten much useful "work" out of this late charcoal combustion
anyway.

9. I would guess that you did have "good" combustion - if you are
making charcoal and having no smoke ("fairly smoke free"). The fact that
you had no flame at the top could be considered good for a cook stove. To
get taller flames you need more primary air. People will also want to know
what the ratio of maximum power output to minimum output (can measure in
terms of time durations also)

10. It will be important eventually to report the weights of input pellets
and output charcoal (25%?).

11. As you are the first to report on secondary air holes that far up, I am
not sure what is happening. It would be interesting to do this in the dark
and report on the nature of the flames. Were they attached to the 20-some
(1/4") holes? (These sound a little large and too far apart.) It sounds
to me like you might have gotten some secondary air inlet below the row of
1/4" holes. Then you got (maybe?) ignition near the (1/4") holes? Can you
describe how tight the fit was between the coffee can ("...6" more or
less...") and the 6# stove pipe? With a flame above, there will be a
substantial draft to bring secondary air in at that junction. (and maybe
even enough to have all your combustion down there. (Using a mirror allows
one to see the flame without singing one's eyebrows).

> Tomorrow I'll try a load of twigs instead of the pellets, and I'll
> insulate the area between the 6" and 8" stove pipe. Also maybe will try
> more secondary air holes lower on the pipe.

RWL 12. I have found it best to load the "twigs" vertically and pretty
tightly packed. I think you can go up to 3 or 4 cm diameter - but 1 or 2
cm should work pretty well also.

13. I think it very important to understand where your secondary air is
coming from now. You may want to remove holes instead (to keep the
temperature up). One possibility is to just close up your existing holes -
maybe they are not doing much right now. (But maybe they are.)

> I just picked up 3 nice little 15 gallon steel drums (13"x25") and
> 3 30 gallon drums (18.5"x29") to experiment with -- wish I could find
> something like a 10 gallon. But I'll burn up some tin cans before I
> start on those.
>
>
(RWL): 14. Be aware that new problems arise as you get bigger. I had
initial trouble even at the 5 gallon (20 liter) scale. (Trouble meaning
getting a short enough flame - you might think about ways to get more
secondary air

More later if you want some hints. What kW level do you want? The 6 inch
size will be several kW. How long a burn do you want?

Best of luck

Ron

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From psanders at ilstu.edu Thu Nov 8 20:08:45 2001
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:17 2004
Subject: Stoves, hmmm!
In-Reply-To: <3BEA007F.35E8EA2C@cybershamanix.com>
Message-ID: <4.3.1.2.20011108190754.016ff8e0@mail.ilstu.edu>

Harmon,

You are doing the experiments that many will soon be doing to see the
gasifier effect.

I think you do NOT want more primary air. It might help get a more
vigorous fire, but there is a limit to the usefulness of blazing fires for
cooking.

I suspect you will want to increase the secondary air.

Also, you said you are using 6 inch cans. I suggest going smaller to 4
inch diameter. But one of the parameters to be tested is exactly
that: impact of different diameters of the gasifier unit.

I am anxious to read of your next experiences.

Paul

At 06:29 PM 11/8/01 -0600, Harmon Seaver wrote:
> Much greater success today! Taking another look at the Reed/Larson
>stove, I realized I'd placed my secondary inlets much too high, so
>drilled another series of holes around the 6" stovepipe just a couple
>inches above where the stovepipe goes into the coffee can. Voila! A very
>nice smokeless (except for a bit at startup) fire, very hot, lasts about
>45 minutes, then turns to glowing coals, then out.
> I'm still not seeing blue flames, but looking down into the stove
>pipe, you clearly see a lot of secondary burning at the point of the air
>inlets. Still big orange/yellow flames, but they look like gas jets
>coming out of all those holes.
> At this point, I'm thinking that maybe I'm not getting enough
>primary air -- certainly I've seen absolutely no need to regulate
>primary air, all I have now is two holes in the bottom (opposing sides)
>of the coffee can punched with a church key. But maybe the holes in the
>bottom of the flower pot aren't enough?
>
>--
>Harmon Seaver, MLIS
>CyberShamanix
>Work 920-203-9633
>Home 920-233-5820
>hseaver@cybershamanix.com
>http://www.cybershamanix.com/resume.html
>
>
>
>-
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From tombreed at home.com Fri Nov 9 09:07:43 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:17 2004
Subject: Fw: Stoves, hmmm!
Message-ID: <02a301c16924$7353dea0$18e5b618@lakwod3.co.home.com>

Dear Kat and Shivayam:

I sent the following note to CPC and Sri Lanka today to stir
up the pot after Art Lilley (vice pres CPC) sent the following message.

TOM

Subject: Re: Stoves, hmmm!

Dear Art and Robb;

I heard 1/2 year ago from Ray Widgewardene that the whole
board of NERD had been fired except himself and he hoped to reactivate the
project.

Heard nothing since. The world is full of good
intentions ... but not many doers. So, if they aren't interested in
helping their people why should we be? Let's forget LDCs and go
where the money is.

So, I am proceeding to "go commercial" with WoodGas CampStoves
for the U.S. market where the innovation, the interest and the money
is.

TOM

----- Original Message -----
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Artsolar@aol.com

To: <A title=tombreed@home.com
href="mailto:tombreed@home.com">tombreed@home.com
Cc: <A title=Robbcpc@aol.com
href="mailto:Robbcpc@aol.com">Robbcpc@aol.com
Sent: Friday, November 09, 2001 4:56
AM
Subject: Fwd: Stoves, hmmm!
Wonder how many people
are working on "Turbo variation". Never did hear whether the Sri Lanka
one got anywhere. Art

From tombreed at home.com Fri Nov 9 09:24:06 2001
From: tombreed at home.com (Thomas Reed)
Date: Tue Aug 31 21:37:17 2004
Subject: Fw: Stoves, hmmm! ==> Whoops
Message-ID: <02c701c16926$bd562e20$18e5b618@lakwod3.co.home.com>

Dear Stoves:

I meant to send this to others, not you. Please ignore.
...

T. Reed

Dr. Thomas Reed
The Biomass Energy Foundation 1810 Smith Rd., Golden, CO 80401303
278 0558; tombreed@home.com; <A
href="http://www.woodgas.com">www.woodgas.com
----- Original Message -----
From: <A
title=tombreed@home.com href="mailto:tombreed@home.com">Thomas Reed
To: <A title=Stoves@crest.org
href="mailto:Stoves@crest.org">Stoves
Sent: Friday, November 09, 2001 6:43 AM
Subject: Fw: Stoves, hmmm!

Dear Kat and Shivayam:

I sent the following note to CPC and Sri Lanka today to stir
up the pot after Art Lilley (vice pres CPC) sent the following message.

TOM

Subject: Re: Stoves, hmmm!

From adkarve at pn2.vsnl.net.in Sat Nov 10 08:32:01 2001
From: adkarve at pn2.vsnl.net.in (A.D. Karve)
Date: Tue Aug 31 21:37:17 2004
Subject: Kilns for cane leaves in India
In-Reply-To: <4.3.1.2.20011030091833.01a49190@mail.ilstu.edu>
Message-ID: <011901c169ef$09ee58c0$7a51c5cb@vsnl.net.in>

Dear stovers,
I am back from New Delhi, where I spent a delightful 5 days attending the
diamond jubilee (60th year) conference of the Indian Society of Genetics and
Plant Breeding.
I have discovered one shop in Pune, that is offering stainless steel barrels
of the size that we want for about Rs. 275 each, which is even cheaper than
mild steel barrels. I do not know, if this is a one-time offer to clear old
stocks, or if the shop would supply the barrels indefinitely at this price.
A.D.Karve

----- Original Message -----
From: Paul S. Anderson <psanders@ilstu.edu>
To: A.D. Karve <adkarve@pn2.vsnl.net.in>; Apolinário J Malawene
<ajmalawene01@hotmail.com>; Bob and Karla Weldon <bobkarlaweldon@cs.com>; Ed
Francis <cfranc@ilstu.edu>; Tsamba--Alberto Julio <ajtsamba@zebra.uem.mz>;
<stoves@crest.org>
Cc: George Wolf <wolfland@gridley.org>; Nick Nayak <nicholasnayak@aol.com>;
Sandra Broadrick-Allen <sandyba@net66.com>; Jared Kosoglad
<thetarsk@hotmail.com>
Sent: Tuesday, November 06, 2001 8:29 PM
Subject: Re: Kilns for cane leaves in India

> At 02:54 PM 11/4/01 +0530, AD Karve wrote:
> >Dear Paul,
> >inquiries made in the local market revealed that ready made stainless
steel
> >barrels were available for about Rs. 400 each, (US$ 8), whereas the mild
> >steel ones, which would have to be specially fabricated for us, would
cost
> >us about Rs. 300 (US$6) each. Our latest model of the kiln takes 9
barrels
> >at a time. The operator needs two sets of barrels, so that while one set
is
> >being heated in the kiln, the second is kept ready with trash to be
charred.
> >In this way, he does not lose time (and heat) between batches. Thus, we
need
> >Rs. 7,200 for the stainless steel retorts and Rs. 5,400 for the mild
steel
> >retorts. All other costs are the same. Thus our revised cost estimate is
> >about 200 Dollars for a kiln with stainless steel retorts and about US$
180
> >for a system having mild steel retorts.
> >The question often asked to us is why we were opting for a small manual
> >operation, when large scale systems producing even 100 tonnes of char per
> >day were available. Our answer to this question is, that the large scale
> >operation was not profitable. Agrowaste is diffused all over the
> >countryside. We have ourselves seen, how costly it is to transport it
from
> >the field to a central processing factory. In a small scale operation, it
> >becomes possible to itransport the processing machinery to the place
where
> >the agrowaste is available. Also, one needs only unskilled labour to help
> >the operator, and because the operator takes the profit from this
business,
> >he does not take a salary for himself. Therefore the overheads are less
and
> >therefore the system can generate a profit.
> >I asked our local bank about the best way to send money but they could
not
> >tell me anything concrete. I shall have to go to the head office, where
they
> >know more about foreign currency transactions.
> >I am leaving for Delhi today and shall return in the evening of the 9th.
We
> >can resume our dialogue after the 9th of November.
> >Yours A.D.Karve
>
> >
>

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From adkarve at pn2.vsnl.net.in Sat Nov 10 08:33:00 2001
From: adkarve at pn2.vsnl.net.in (A.D. Karve)
Date: Tue Aug 31 21:37:17 2004
Subject: storing hot charcoal in an airtight container
In-Reply-To: <4.3.1.2.20011106125510.01a58970@mail.ilstu.edu>
Message-ID: <011801c169ef$0935b720$7a51c5cb@vsnl.net.in>

Dear stovers,
we used charcoal stoves in our own household, about 50 years ago. The
charcoal left in the stove after the cooking was over used to be stored in a
tin can with a lid that fitted so tightly, that one had to use a spoon
handle to pry the lid open.
A.D.Karve
----- Original Message -----
From: Paul S. Anderson <psanders@ilstu.edu>
To: <kenboak@stirlingservice.freeserve.co.uk>; Apolinário J Malawene
<ajmalawene01@hotmail.com>; Bob and Karla Weldon <bobkarlaweldon@cs.com>; Ed
Francis <cfranc@ilstu.edu>; Tsamba--Alberto Julio <ajtsamba@zebra.uem.mz>;
<stoves@crest.org>
Sent: Wednesday, November 07, 2001 3:06 AM
Subject: Re: More on best stoves