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Dear Stovers,
At Chardust in Nairobi we use our downdraft pit
system to carbonise a number of materials for briquetting. Coffee husk is one of
the best. It has a low moisture content so
requires no pre-drying; it is of homogenous size and shape; it is
available right in urban centres (such as Nairobi and Kampala), which
reduces transport costs when competing with lumpwood charcoal; it carbonises at
an efficiency of 33%; and the final product is relatively low in ash, even after
the addition of binders.
Stephen Gitonga of ITDG mentioned the efforts of
the Kenya Planters Cooperative Union (KPCU) to market coffee husk charcoal
in Kenya. These began in 1987 but have pretty much ended, with over 600 tonnes
unsold at the KPCU depot. The product was unpopular with consumers due to its
smokiness, and the marketing operation was run inefficiently as an off-shoot of
a para-statal organisation. We're re-branding the product as BBQ charcoal and
packing in clean 4 kg sacks for supermarkets and convenience stores. The smoke
problem persists to an extent, regardless of which binder is used, for
10-11 mins after lighting. We're trying to improve the efficiency of our
carbonisation to see if it can be eliminated, but it may be something inherent
in coffee husk that cannot be avoided. For a BBQ market (outdoor) it's not a
major problem in any case.
We were recently in Uganda and looked at the
opportunities there. Lumpwood charcoal is fairly cheap in Kampala @ US$0.08-0.09
per kg so a coffee husk charcoal plant might require subsidy. But there's plenty
of arabica husk available at mills around Kampala. Robusta husk is less
accessible as it tends to be processed at farm level by smallholders. The husk
volumes are significant: Uganda exports 3 million bags of coffee per annum
(180,000 tonnes), and up to 30% of arabica and 50% of the robusta bean
apparently ends up as husk.
The use of processing wastes (such as husk) is
becoming more of an issue for the coffee industry in these days of
environmental awareness and corporate social responsibility. One set of
industry guidelines, drawn up by the Consumer's Choice Council and others, can
be downloaded at:
Under the heading of 'Waste
Management' it's stated that 'Waste and coffee by-products are managed to
minimise environmental impacts by applying the principles of reduction, reuse
and recycling'. There's probably industry financing out there somewhere to
support husk conversion in charcoal markets where subsidy is
required.
Matthew Owen
Chardust Ltd.
Nairobi
----- Original Message -----
Sent: Tuesday, March 05, 2002 7:56
AM
Subject: RE: Coffee husks as fuel
Dear Zoli,
Good question you asked.
In the
top-downward gasifier approach to pyrolysis, we are not able to add additional
fuel on top of the pyrolysis layer. Therefore, we need the pellets or
small briquettes to let it "breathe" from the bottom.
Paul
At
09:43 AM 3/4/02 +0200, Zoli Bihari wrote:
John, Paul and Stovers
I'm asking myself, why should you pelletize the coffee
husk?
It burns wonderfully as is, if you manage to
keep
it in a thin layer on a grate.
That way, the naturally induced air can pass trough it
and you get a very nice fire.
By the way, you should mention what type of
coffee residue do you have.
In Kenya they
have parchment, which is one of the inner
layers,
and the M'Buni, which is the outer skin and flesh together.
Zoli
Zoli Bihari
R&D - Ormat Ltd. - Israel
Tel: 972 (8) 9433894
Fax:
972 (8) 9439901
E-mail: zbihari@ormat.com
> -----Original Message-----
> From: Paul S. Anderson [mailto:psanders@ilstu.edu]
> Sent: Sunday, March 03, 2002 9:42 PM
> To: John Olsen; stoves@crest.org
>
Subject: Coffee husks as fuel
>
>
> John,
>
> I did not understand if you ALREADY are able to
make and are actually
> making the briquettes
from coffee husks. Please give more
> details. We
> need to know
about how much pressure OR if binders are needed OR
> output-of-heat results OR any other data about use of coffee
husks.
>
> Also, do
you mean briquettes in the "standard" sizes (ala
> Richard Stanley
> or ELK) or in the
the larger "log-type" fuel units that your machine
> produces so well?
>
> Perhaps someone would volunteer to check on "coffee husks as
> fuel". I
> would think that the major coffee producing countries would
> have looked
>
closely at this issue.
>
> Paul
>
>
At 10:28 AM 3/3/02 -0800, John Olsen wrote:
>
>Paul said.............You identify Coffee bean husks. If
> not already done,
>
>work needs to be done on
> >making those
husks (and sawdust and other stuff) into a "processed
> >fuel"..................
>
>This area of commerce is an important part of my sales
> effortfor making
> >Briquettes
from Biomass.
> >The coffee growers by using
the husks as a briquette fuel,
> can roast
the
> >coffee before export, instead of just
exporting the bean.
> >regards
> >JohnO
> >
> >
> >
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 -
7/00
Rotary University Teacher Grantee to Mozambique >10 mo of
2001-2003
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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