Re: Stove efficiency

["A.D. Karve" <adkarve@pn2.vsnl.net.in>]

Dear Kevin,
I called coal the cleanest burning fuel because it burns to form CO2,
without producing soot or smoke.  The traditional village cookstove is not
designed to burn charcoal, because agricultural residues, wood and dung
cakes, which represent the most commonly used fuels, produce a flame.
Therefore, the traditional cookstove has a gap of about 10 cm between the
fuel and the pot.  Because the traditional cookstoves do not have a grate,
the burning fuel does not get a good supply of air. Therefore, when dense
materials like sticks, branches and coconut shells are burned in these
stoves, some unburnt residual charcoal is also produced as a byproduct.  The
charcoal is stored separately and either sold to village blacksmiths, or
used in a separate charcoal burning stove.  In the latter, the pot sits very
close to the burning charcoal, because there is no flame.
Our char briquettes are produced from light biomass such as fallen leaves of
trees, sugarcane leaves left in the field after sugarcane harvest, wheat
straw, threshing floor debris etc. which cannot be burned directly in a
cookstove.  This material is charred in an oven-and-retort type of a kiln
and the char is extruded into cylindrical briquettes. This fuel is meant
primarily for the poor in the cities, who cannot afford kerosene or liquid
petroleum gas. In my childhood about 60 years ago, the city dwellers used
charcoal, which was made from tree logs.  In order to save the trees, the
Government of India made kerosene available to them at a very low price.
That weaned the city dwellers away from wood and charcoal.  But about two
years ago, the world bank twisted the arms of our government to reduce
subsidies, including the one on kerosene.  Therefore, kerosene, that used to
cost Rs. 4 per litre, now costs Rs. 13.  A family uses daily one litre
kerosene.  Therefore the urban poor are reverting back to using wood and
charcoal. We can sell our briquettes in the cities at Rs. 7 per kg, and
using our configuration of stove-and-cooker, a family of 5 can cook all
their meals with just about 400 g of the briquettes, which would cost them
less that Rs. 3 per day. Since our char briquettes are made from
agricultural residues and not from wood, their use would automatically save
trees. The state of Maharashtra, where we operate, has the potential of
producing anually about 10 million tonnes of char briquettes from various
agricultural residues. We are propagating this system in our our area.
Using generous support from the Champaign West Rotary Club (mediated by Paul
Anderson), Council for Action by the People and Rural Technology (a funding
agency of the Government of India), and the Ashden Award, London, we are
planning to set up about 40 kilns as demonstration units all over
Maharashtra.  This process presents a great opportunity to the rural poor to
earn a decent income without having to leave their villages.
A.D.Karve

-----Original Message-----
From: Kevin Chisholm <kchisholm@ca.inter.net>
To: A.D. Karve <adkarve@pn2.vsnl.net.in>; Paul S. Anderson
<psanders@ilstu.edu>
Cc: stoves@crest.org <stoves@crest.org>
Date: Tuesday, May 07, 2002 9:01 PM
Subject: Re: Stove efficiency


>Dear Dr. Karve
>
>Subject: Re: Stove efficiency

>Among all the fuels used in rural India, charcoal burns the
>> cleanest.
>
>Is that perhaps because charcoal is reasonably consistent in size, moisture
>and burning characteristics, and that perhaps that the stoves in which the
>charcoal is burned are of a design which is appropriate to burning
charcoal?
>



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