Re: GAS-L: NOT (Re: Kilns), but CHECK THE TITLE

["Kevin Chisholm" <kchisholm@ca.inter.net>]

Dear Tom
----- Original Message -----
From: Tom Reed
To: Kevin Chisholm ; Ron Larson ; gasification
Cc: THodson@aol.com ; Paul S. Anderson ; stoves@crest.org
Sent: Monday, November 25, 2002 8:54 AM
Subject: GAS-L: NOT (Re: Kilns), but CHECK THE TITLE


Dear Kevin and all:

I suppose Kevin's complaint is justified for some and we should stick to
plain text when possible (which is most of the time).

(Kevin Said This.)Considering the nuisance caused by HTML, when is it ever
justified on these Lists?

However, even better would be a resolution on all our parts to use
appropriate titles.  We are all guilty of hitting the reply button, changing
the subject of the body but not the title.

PLEASE CHECK THE TITLE LINE BEFORE SENDING.  We DO archive all this stuff
and the archives are unnecessarily cluttered when we ignore the tile line.

Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone/Fax
----- Original Message -----
From: Kevin Chisholm
To: Ron Larson
Cc: THodson@aol.com ; Paul S. Anderson ; stoves@crest.org
Sent: Monday, November 25, 2002 3:43 AM
Subject: Re: Kilns


Dear Ron

You go to a lot of effort to deal with HTML posts, to enable the reader to
understand "who said what."

HTML has no redeeming social merit, as far as I can see!! :-)

What about if all those posting to the CREST Lists did so in Plain Text? It
would make life very simple for all of us?

Kindest regards,

Kevin Chisholm

----- Original Message -----
From: Ron Larson
To: A.D. Karve
Cc: THodson@aol.com ; Paul S. Anderson ; stoves@crest.org
Sent: Sunday, November 24, 2002 11:24 AM
Subject: RE: Kilns


AD

See notes below:
-----Original Message-----
From: A.D. Karve [mailto:adkarve@pn2.vsnl.net.in]
Sent: Sunday, November 24, 2002 2:04 AM
To: Ron Larson
Cc: THodson@aol.com; Paul S. Anderson; stoves@crest.org
Subject: Re: Kilns


Dear Ron,
we have two types of extruded briquettes. One set has a diameter of about 19
to 20 mm and the other has a diameter of about 12 to 13 mm.  However,
because of the problematic electrical supply in the rural areas, we have now
opted for the honeycomb briquettes, which are made manually, using a mold.
The honeycomb briquettes have a diameter of about 12 cm and height of about
3 cm.  Each briquette has 13 vertical holes. Paul Hait wanted to know if we
are using the thermal array type of arrangement of briquettes in our stove.

[Ron Larson]   For new stoves list members, we should say that Paul Hait
developed a charcoal using system in which the "pillow" type briquette was
carefully placed vertically in slots and in rows in such a way as to get the
radiation from one impinging on another - with good air flow.  I don't
recall the percent reduction in charcoal consumption - but it might have
been a factor of four or five.  He also used stainless steel (reflective)
parts and a clever fold-up design to get higher efficiencies and user
convenience.
        Paul's question is important in "holey" (or "honeycomb") briquettes,
because the same principal of getting good use out of the radiated energy
(inside the holes as opposed to going off to be absorbed in something other
than the cook pot) helps improve combustion enormously.
    In your case, what is the diameter of the 13 vertical holes?
    How does this diameter change during a run?
    Is there a brittle "ash" skeleton remaining at the end?
    How long does a single briquette last?  (presumably one being long
enough for cooking the meal you describe)
    Could you make one twice as tall to cook for twice as long?  (In a
different culture)
       Is there a "haybox" effect also? (some cooking after the single
charcoal briquette is consumed?)
    Could you describe how lighting is achieved?
    Approximately how high above the briquette do the flames appear - and
how does this distance change during a single cooking?
    What are the prices of all of the components of the system - including
for a single briquette?
    What lifetime do you expect for the charcoal burner?  (presumably the
cookpot portion is much longer-lived)
    Will this particular pot and shield be available for export to
interested members of "stoves"? at what price?



  The answer is "no", because with a single honeycomb briquette, no
arrangement is possible.  When we were using the cylindrical (extruded)
briquettes, be just weighed 100 grams of them and put a single layer of
briquettes spread evenly on the grate of the stove.
We use grain starch as binder.  The flour fallen on the floor of a flour
mill is swept and sold by the mill operator at a price of Rs. 2 per kg
(Rs.50 per US$). The cost of the char is Rs. 3 per kg. Because the flour is
not costlier than the char, there is no restriction on the quantity of the
flour. We boil about 400 g of flower in 1.5 litres of water and mix it
thoroughly with 1 kg char to make a dough.  This dough is filled into the
briquette mold and the briquettes are dried in the sun
[Ron Larson]   Does this mean that you might have a wet mix of about 2.9
kg - going to a dry batch of  maybe 1.5 + kg - so this recipe might give
15-20 briquettes - with a raw material cost of about 5 rupees or US 10
cents - so one briquette (one meal) has a raw material cost of less than 2/3
cent?

Our stove is a commercially available charcoal burning stove, made of mild
steel sheets. The stove is 11 cm tall. The cooker consists of a stainless
steel container, about 21 cm tall and 18 cm wide, closed with a lid, which
is not too tight. The gaps between the container and the lid allow steam to
escape. Inside the cooker, three cook pots are stacked one on top of the
other, so that three things (rice, beans and vegetables) can be cooked
simultaneously. The cooker sits on the stove with a gap of about 12 mm
between the burning briquette and the bottom of the cooker pot.  The cooker
and the stove are together enclosed in a vertical stainless steel sleeve,
about 29 cm tall and 19 cm wide.  There is thus a gap of about 5 mm between
the cooker and the sleeve, through which the flue gases pass.
[Ron Larson] :  We have talked often about the optimality of this 5 mm
dimension.  Any experimental data?
    Have you measured the output temperature of the exhaust gases?
        Same for temperature of the outermost wall?
    If we knew the weight loss per unit time (presumably higher at first?),
we could estimate the power output levels.  There are several on the list
who could do this measurement quickly using their balancing scales.

 (RWL):  I believe there is much to be learned from your geometry - and hope
others will try similar geometries.  This is a very high efficiency being
reported - and possibly is very clean as well - given the high temperatures
that are likely being achieved because of the honeycomb nature of the
briquette.
    (AD - we look forward also to hearing about emissions at some time.
I'll bet they also look very good.)


 The top 4 cm of the cooker are not covered by the sleeve, because the
cooker is provided with two small handles that are attached to the sides of
the cooker at this height.These handles allow the cooker pot to be lifted
out of the sleeve.
The efficiency was tested by the usual water boiling test.  The housewives
who used the cooker were also astonished by the fuel economy of this stove.
Using a traditional wood burning cookstove, a housewife would have to use 3
kg wood to cook the three items mentioned above.
We have no means of controlling the air flow. We may be able to increase or
reduce the power output of the stove by using more or less of the fuel.
Yours A.D.Karve
[Ron Larson]:
      Have you tried (or could you try) cooking with two briquettes of
half-height?
    Might power level control then be possible by rotating one briquette
relative to the other?
    In Johannesburg, the GTZ folk were showing an example of the "punch-out"
"Turbo" stove from Finland that we have discussed on this list a few times.
(Incidentally -very nice looking product that comes shipped in a big flat
(pretty heavy) box.)   It had a very clever air flow control (that I had not
previously noticed) by rotating one set of holes relative to another.  You
might be able to do this same with the briquettes to achieve power control.

AD Thanks and congratulations again - for what I think must be the world
record.  I believe this is better than my electric range.   Ron


-----Original Message-----
From: Ron Larson <ronallarson@qwest.net>
To: A.D. Karve <adkarve@pn2.vsnl.net.in>; THodson@aol.com <THodson@aol.com>
Cc: Paul S. Anderson <psanders@ilstu.edu>; stoves@crest.org
<stoves@crest.org>
Date: Saturday, November 23, 2002 8:31 PM
Subject: RE: Kilns


A.D

1.    Thanks for sending this interesting story on.   Not a permanent
problem - hopefully, just a new point to add to your educational program.
Old ideas die hard.


2.  What are the dimensions and weight of your briquettes?  (Number making
up 100 g?)

3.  You probably said this earlier - but what is your recommended binder
formula?

4.  You have described your new stove previously, but I think it needs a
repeat - as 70% is just fantastic.  Congratulations!!

5.  I do not recall anyone claiming this high an efficiency value.  I
believe you have incorporated what we might call a
"convection-enhancing-sleeve" which is probably key to this high value
What is the gap width and height you have chosen in the model now in
production?  What is the method of measurement?

6. Do you have any means of controlling air flow and power level of this
stove design?


7. It is becoming more clear all the time that the Ashden award people made
a wise choice.

Ron
-----Original Message-----
From: A.D. Karve [mailto:adkarve@pn2.vsnl.net.in]
Sent: Saturday, November 23, 2002 4:20 AM
To: THodson@aol.com
Cc: Paul S. Anderson; stoves@crest.org
Subject: Re: Kilns


Dear Tom and Paul,
I spent the last four days at Phaltan, looking at the charring kilns
installed by ARTI at various sites.  The operators in most cases are
unemployed rural youth.  After demonstrating the process to them on our own
kiln they were provided with a kiln of their own, and they were asked to
char sugarcane leaves in their own villages.  In all the cases, they had
unofficial advisers, who had already made charcoal using the traditional
kilns.  In the traditional process, the biomass to be charred is loaded into
a kiln and ignited.  One has to regulate the air supply very judiciously in
order to have the right temperature to cause the biomass to char, but at the
same time not provide so much oxygen that the biomass burns down completely
to produce ash.  In our oven and retort model, the biomass to be charred is
enclosed in barrels and it never comes in contact with oxygen.  We therefore
keep all the airholes fully open, so that the biomass surrounding the
barrels burns intensely to pyrolyse the biomass inside the barrels.  Our
entrepreneurs unfortunately followed the advice of the traditional charcoal
burners in their villages and contrary to our advice, closed all the air
vents, resulting in a very slow burn of the biomass surrounding the barrels.
This not only increased the batch time but also in producing biomass which
was just roasted and not charred.
Most of them were totally discouraged, firstly because of low output and
also because of its poor quality.  The correct process had to be
demonstrated again at each site. We thought that we had developed a fooproof
process, but it turned out that we were the fools believing that the
villagers would easily be able to produce char using our technology. Our
technology, if correctly employed, would yield about 50 kg char per 8 hour
shift.
The char is sold in the form of briquettes. We started out with the
extrusion process to convert the char into cylindrical briquettes. But in
the field, there are problems with electric supply (either too low voltage
or no electricity at all).  So, during my stay at Phaltan we took the
decision to provide the entrepreneurs with molds to produce the so called
honeycomb briquettes manually. These briquettes look like mud pies, they
weigh 100 grams each and each briquette has a set of 13 holes. So when it is
ignited, the pot is hit by 13 flames. I myself produced these briquettes at
the rate of one per minute.  Thus by using our mold, a person can produce 50
kg dry briquettes per day.  If the entire family works on this process, they
can earn Rs. 250 per day (US$ 5), which is more than what an average
industrial worker earns in a city.
We have developed a stove-and-cooker system for using the char briquettes
most rationally.  Through using a very scientific design, we achieve 70%
efficiency with our stove-and-cooker. Just 100 grams of briquettes can cook
rice, beans and vegetables for a family of family.  We tested various
prototypes and have now given orders to a stainless steel pots manufacturer
to mass produce this cooker.  We expect to get the first batch of cookers in
about a fortnight and then see how we can market them.  We shall sell them
very cheaply (at practically no profit), because the user of a cooker is the
potential buyer of the briquettes.
Yours
Dr.A.D.Karve, President,
Appropriate Rural Technology Institute
Pune, India.


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