Dear Dr. Karve,
All sounds excellent and workable within the
economics of your own situation. Although we don't have quite so much unused
agricultural residue in East Africa, the other aspects of your operation sound
similar in principle to our own. At Chardust in Nairobi we have not yet started
to involve 'out-suppliers' in bringing us the pre-carbonised material, as we can
get sufficient supplies of waste charcoal vendors' dust for the time being to
support our briquetting operation, and are actively pursuing sugar companies and
sawmillers who have large point sources of waste biomass that we can carbonise
ourselves. But getting small-scale farmers to bring such pre-carbonised material
to the briquetting unit is certainly something one might get into in the future,
as lumpwood charcoal prices continue to rise and the economics of introducing
another step in the production chain get increasingly favourable.
I saw something similar to what you describe around
Lampang in central Thailand last year. Farmers are growing bamboo and processing
it at rural factories to make chopsticks and toothpicks. All the jointed
sections of the bamboo used to be thrown away, but now two briquetting
companies in Lampang get the farmers to carbonise this waste and bring it to
their factories in pick-up trucks. They weigh the offloaded sacks of material
and pay the farmers cash by the kg.
The only problem I saw was that the farmers use
rather rudimentary carbonisation systems which are in fact nothing more than
very large open cylinders into which the bamboo pieces are heaped and then lit.
This obviously leads to low conversion efficiencies and high ash content, as
well as some poorly burned lumps of bamboo, but they were working on
improvements for the sake of their own efficiency and fuel quality. They use 5%
tapioca flour as a binder and bake the briquettes in gas ovens, something which
would not be competitive in East Africa so we use clay instead - as I believe
you do too (?).
The main market for the Lampang charcoal is an NGO
consortium that supplies fuel to about 100,000 Burmese refugees. They buy
around $2 million worth per annum!
Matthew Owen
Chardust Ltd.
P.O. Box 24371
Nairobi
Kenya
----- Original Message -----
Sent: Tuesday, January 16, 2001 1:51
PM
Subject: Re: Charcoal in East
Africa
Dear Matthew,
you are right about the high cost and low
calorific value of briquettes made out of compacted sawdust and other
biomass. Charring it is simple and briquetting the char is also quite
simple. Both can be done at a very low capital cost by a third
world farmer. We have modified an old fashioned meat mincer into an
extruder. We first operated the extruder manually, and after being
satisfied with its performance, we are now fitting it with an electric
motor, to increase its output. But the extruder is not obligatory,
as one can just manually shape the charred biomass (after mixing it with
a binder), into balls having a diameter of about 5 to 6 cm, and dry them in
the sun. These balls can serve as fuel not only in a conventional
charcoal burning stove but even in a pyromid stove.
There is no real shortage of firewood in the
rural areas of our state (Maharashtra, India), because of the availability of
combustible agrowaste in the form of stalks of cotton and pegionpea, as well
as abundant availability of Prosopis juliflora (mesquite) trees. The farmers
have a lot of light biomass which is today not used as fuel (e.g. dried
sugarcane leaves, wheat straw, stover of safflower, sunflower, sesame, mustard
etc.), and often just burnt in situ, just to get rid of it. The farmers
are not interested in making charcoal briquettes out of this biomass for
their own use, but if somebody arranges to collect the charred biomass
from the farmers, and produces them into briquettes, there is a good market
for the latter in the cities. We have formed a cooperative,
which would do just this. We do not see any difficulty in selling
the char briquettes in the cities, because there exists a ban of the
production of wood charcoal (as a measure of saving the trees). As a result of
the ban, the charcoal prices have shot up to US$ 150 per tonne.
Yours A.D.Karve
Sent: Tuesday, January 16, 2001 11:13
AM
Subject: Re: Re: Charcoal
Piet,
In our part of the world (East Africa), the use
of sawdust in uncarbonised form comes up against basic economic constraints.
As an example, we had an NGO making sawdust briquettes in Isiolo, a large
town in the drylands of northern Kenya ('SALTLICK'). They used reject grade
gum arabic (Acacia senegal) as the binder and the work was done as a cottage
industry using manual presses. The dried fuel briquettes had an energy
content of 18 MJ/kg vs. about 16 MJ/kg for dry firewood. Yet their retail
price was approximately the same as that of charcoal, which has an energy
content of over 30 MJ/kg, due to the labour required to source the raw
materials, mix them and operate the presses (vs. firewood collectors who
wander into the bush and cut what they like). That comparison basically
spelt the demise of the project. You can't sell something at the price
of charcoal when it has roughly the same energy value as wood. Consumers
began to realise that the fuel was burning more quickly than they thought it
would, with less heat output than they had been led to believe, and they
stopped buying it.
I imagine that the situation of very cheap
firewood is replicated in many other developing countries due to the absence
of formal controls on harvesting and transport and the low cost of labour.
Since I came to Kenya in 1990 the price of firewood has 'only' doubled,
whereas the value of the local currency has diminished by a factor of 10.
Its local purchase price simply doesn't reflect any dependable economic
indicators, and it is a fuel against which no-one can compete without a
drastic change in the way its sourcing is controlled.
Hence our decision (with Elsen Karstad
at Chardust Ltd.) to get into charcoal fuels. We CAN compete against
charcoal as it is an urban middle class fuel for which people are willing to
pay above the odds for convenience and quality. It is transported as far as
250 km into Nairobi and the retail price is normally around $90 per tonne.
This gives the formal sector some chance to compete. Note that we cannot
afford to extrude the sawdust and then carbonise the briquettes due to the
incredibly high pressures and temperatures that this requires. We have
decided to carbonise the sawdust first and then briquette it afterwards at
low temperatures and pressures to keep costs of machinery and electricity
down - for which we must accept a higher ash content (but longer and more
even burn).
Jim Dunham mentions that he has successfully
set up units all over the world to briquette raw biomass such as sawdust.
Certainly I suspect that what I've said about raw sawdust briquettes doesn't
apply in many developed countries, where firewood prices are much higher and
a greater value is placed on proper use of residues. There may indeed be an
opportunity to compete in such circumstances.
Then again we don't have to contend with
any emissions regulations either during manufacture or final combustion,
which although we aim to flare all volatiles and produce low emissions
fuels, does allow us a certain experimental leeway out at the production
facility that Jon Flottvik in British Columbia would die for!
Matthew Owen
Chardust
Nairobi
