[Stoves] Charcoal kiln based on Champion Stove.

[adkarve]

Dear Paul and Ron,
our single barrel kiln was designed for urban leaf litter. The avenues in
cities have a single tree species planted on both the sides of the road. One
keeps the kiln on the side of the road and collects the leaves fallen
underneath two or three trees, chars them, and shifts the kiln a few meters
further along the road, to tackle the next load of leaves. The leaves are
just dropped into the barrel and not packed tightly. Tight packing blocks
the primary air. The charring process is stopped by removing the lid along
with the chimney, and sprinkling a little water on the burning leaves. The
barrel is fitted with handles. The char is removed by upturning the kiln
over another barrel, that serves as a store for the char. Water is again
sprinkled on the char, after it has been introduced into the char storage
barrel. A full watering can fitted with a shower head or rose can serve ten
batches. It is still too early to talk about the life of the kiln, but it
would certainly last longer than the stainless steel barrels in the
oven-and-retort system.
We are still tinkering aound with this model. Priya would send you the
picture of one version of this kiln. We are still experimenting with the
chimney height and the gap width for the secondary air. Dry leaves have
quite varying properties. Some are thick and fat, so that they remain flat
even after drying. One can accommodate 10 kg of such leaves in a single
barrel, but because of less empty spaces between the leaves, the primary air
supply gets choked. A long chimney is desirable in such cases. In the case
of leaves that curl while drying, one gets about 5 to 7 kg per batch, but
the supply of primary air is sometimes too much and a part of the leaves
burn to ash. One needs a shorter chimney is such cases. It is not as
foolproof a system as our oven-and-retort system. Therefore, the operator
needs some practice to judge how much biomass he should load into the kiln
and how long to burn each load.
yours
A.D.Karve
----- Original Message -----
From: Paul S. Anderson <psanders at ilstu.edu>
To: Discussion of biomass cooking stoves <stoves at listserv.repp.org>; adkarve
<adkarve at pn2.vsnl.net.in>
Sent: Monday, June 11, 2007 6:56 PM
Subject: Charcoal Champion Stove. Was:[Stoves] Charcoal Rocket Stove


> A.D.,   (with note at end for Ron Larson about this topic)
>
> A.D.'s application of the Champion stove sounds very good to me.
>
> Can you send pictures, please, and also dimensions of the chimney and the
size
> of the gap for the secondary air.
>
> It will be interesting to learn of the life-span and manufactured costs
> of this
> arrangement compared to that of the other system (stainless steel
multi-drums
> in one larger drum), taking into account the char production.  One
hypothesis
> is that the single drum could last proportionately longer because the
outside
> surface stays "cooled" by the ambient air.
>
> 2 kg of char being a 30-33% return means about 6 kg of field-dried raw
> material
> at the start.  6 kg does not seem like very much.  How tightly is the drum
> packed?  Tighter packing will impact the air flow, but perhaps more
chimney
> could allow for more fuel.  This is to be discussed more.
>
> What is the feed-stock (bagasse, cane leaves+tops, chickpea stems ?) and
how
> many more can you test?
>
> Approximately how large of field area (square meters) provides the fuel
> for one
> batch?  and how many times can a barrel be filled without moving it?
> This is a
> logistics "opportunity" to examine.  I am sure that the field workers
> will have
> that aspect optimized very quickly.
>
> How is the char removed?  Do you smother it (as with lids or into
air-tight
> containers) or do you "air-cool" the char so that it stops combusting?
>
> If the char production is an economically viable activity even without
> using the
> generated heat, that is fine.  At least the workers should be able to have
hot
> water for end-of-day bathing if they finish near a stream or well and rig
up a
> water-jacket or something for the chimney for that last operation of the
day.
>
> I can also imagine some appropriately-sized-version of the Champion
> stove being
> in the village.  At the end of the day, the worker carries home a load of
the
> biomass in a tied bundle or in a sack.  Big and bulky, probably, but
> sufficient
> fuel for cooking in a 100 or 50 or 25 liter barrel-based Champion stove
> that has
> places for the pots, etc., that is, truly configured to function as a
stove.
>
> How long does it take to pyrolyze one one batch of fuel?
>
> For Ron and others:  Because the Champion stove is a true TLUD and has
> very good
> capabilities for charcoal making, there is a major advantage concerning
Terra
> Preta and carbon cycles.  The field-wastes that are the fuels in this
> 200 liter
> Champion stove would otherwise have been burned in the fields or left to
> rot/decay.  Field burning or rotting does not leave much fixed carbon
> (char) in
> the fields.  Of course, A.D.'s usage is designed to carry the char away to
be
> briquetted and sold, so that also leaves the fields.  But if the
carbon-credit
> system ever got established enough to match or exceed the market value of
that
> raw char (not briquetted and not transported and not marketed), then the
char
> could be put back into the field quite easily.  And (according to the
concept
> of soil building via char, as in Terra Preta) that would improve the soils
for
> future years and years and years of use.  And just think that the field
> workers
> have been valued players in the removal of tonnes and tonnes of CO2 from
the
> atmosphere.
>
> Paul
> --
> Quoting adkarve <adkarve at pn2.vsnl.net.in>: