Forwarding Prof. Matirena on briquette work in Cuba and "binders"

["Ron Larson" <ronallarson@qwest.net>]

Hi Professor Martirena  (cc stoves):

	I am guessing that you received a "bounce" from "stoves" because I only
received one copy of your message - and so am sending this on to the whole
list (minus some at the end - and with a few comments below).  But first I
thank you for this very useful addition to our dialog.

	We have used the word "binder" two ways on this list.  I meant the way
Andrew Heggie graciously replied in his recent reply (binder being a string
or wire around a "sheaf" of grass or straw") - but I probably misunderstood
him.  He probably earlier meant "binder" in the exact manner you have
described below - which is also usually the way we have meant it on this
list (as the added non-biomass material used to hold the biomass together
better in a briquette.)  I apologize to all for not picking a better word
(but I can't think of one - anyone got a suggestion?)

	Just a few insertions below:


-----Original Message-----
From: Fernando Martirena [mailto:f.martirena@enet.cu]
Sent: Monday, October 07, 2002 7:59 PM
To: ronallarson@qwest.net
Cc: stoves@crest.org; Smail Khennas
Subject: Fw: "binding machines" (or alternatives)


Dear Andrew, dear Ronal:

Smail Kennas from ITDG (Rugby, UK) kindly passed  this message exchange on
to me.

I have been developing in Cuba during the last few years a technology for
small scale briquetting, oriented to briquetting agriculture-waste and
basically all kinds of burnable wastes. This project was co-financed by DFID
through the coordination of Intermediate technology Development Group (ITDG)
in UK where Smail Kennas has been my counterpart. GTZ (German Technology
Exchange service) has also co-financed some parts of this project. This is
also one of the leading projects coordinated by the network ECOSUR
(www.ecosur.org )

	(RWL):  This is a new (to me) and very interesting site.  ("sur" meaning
"south" here)   I will go back and look more closely.  You are in some good
company with your many partners here.

We have achieved very interesting, and often exciting results. Our aim was
to find an alternative to the usually costly extruder machine used to pack
biomass to use it as a fuel. Because of the high pressure exerted, this type
of press presses the biomass without a binder. The result is a very dense
briquette, with good firing properties, however produced at a very high
cost. Maintenance costs are specially high for because of excessive wearing
during operation.

Our approach was to develop a simpler technology, whereas we could produce a
less dense briquette with a therefore simpler -and cheaper!- machine. Our
first choice was the world wide known CINVA-RAM machine used to produce the
Compressed Earth Blocks (CEB). This is a hand operated machine that exerts a
pressure of around 30-70 kg/cm2 (3-7 MPa). This proved not to be practical,
and we decided to design and operate our own machines, based on the very
same principles, that is, a lever that applies a compressive force through a
piston that presses the biomass into a briquette shaped like an ordinary 6
cm x 13 cm x 24 cm brick.

	(RWL):  There was a relatively high power (maybe 20 - 50 hp? or kW?) brick
making machine at the WSSD - making very strong unfired bricks for a
"Habitat" house.  I asked about the manual (CINVA-RAM) apparatus you
describe and was told that they sometimes do use that in remote locations
(of course not needed or as cheap in Jo'burg).  Their bricks were of an
interesting doubly-interlocking design for better wall strength - presumably
something we stovers never need.  I also asked them about making lightweight
insulating "bricks" for stoves - but I never got to the right person.  You
are working with a very nice technology.)

For this very low pressing pressure a binder is used. We read all about
different experiences throughout the world -kindly provided by Andy Roussel
from IT Consultants (arconsult@cwcom.net) - and found out that in our case
ordinary clay was the best choice. We have done ever since a detailed study
that included clay/binder proportioning, calorific value and burning
properties of the product, by us called "Solid Fuel Block" (Bloque Solido
Combustible in spanisch). If requested, some of the results of this
investigation are available in PDF format.

	(RWL):  Yes, if you will send this to myself and to "Tom Miles"
[tmiles@trmiles.com}, we (mostly Tom) will figure out the best place to
archive what sounds very interesting.

As a result we have obtained a product which looks like an ordinary fired
clay brick, burns very quickly, with a calorific value of around 13-15 MJ/kg
(similar to wet firewood), a density (dried) around 300 kg/m3. We managed
with the support of DFID, GTZ, the ECOSUR network and local partners to set
a pilot workshop into operation since February 2002. The second workshop
will soon be set into operation, after the successful start of the first
one. The product is being sold to local brick manufacturers, quicklime
manufacturers (where it can replace some of the firewood used to burn lime)
and -most of all- to collective kitchens, bakeries, restaurants whose
cooking facilities are dependant from firewood. I could send you some
pictures if requested.

	(RWL):  Yes please send as above.  We try to avoid sending long messages
(PDF and photos) as so many "stoves" people have to pay for time used.

As I said before, we have been working in this subject during the last few
years, and we have accumulated some experience. If this is interesting to
any of you, just let us know. Our technology is almost ready to be
disseminated throughout other areas of thr world, provided there are the
required financial means.

Ok, hope not to have bored you with my message.

	(RWL):  Absolutely not.  If you have any experience with "holey"
briquettes, I think this list would also enjoy those comments.  I look
forward to seeing the greater detail and the photos.  Thanks to Smail for
passing on your/our mutual interests.  To subscribe (free) to "stoves", use:
List-Subscribe: <mailto:stoves-subscribe@crest.org>

	Good to receive your message - and look forward to more.   Ron

Sincerely

fernando
____________________________
José Fernando Martirena Hernández (Prof. PhD Ing.)
CIDEM Facultad de Construcciones/Faculty of Constructions
Universidad Central de las Villas/Central University of Las Villas
Carretera de Camajuani km 5, Santa Clara 408000, Villa Clara. CUBA
tel/fax: ++53 42 281539 (oficina/office)
tel/fax: ++53 42 203065 (casa/home)
e-mail: F.Martirena@enet.cu
website: www.ecosur.org


----- Original Message -----
From: "Smail Khennas" <smailk@itdg.org.uk>

> -----Original Message-----
> From: AJH [mailto:andrew.heggie@dtn.ntl.com]
> Sent: 06 October 2002 23:59
> To: stoves@crest.org
> Subject: Re: Reply to Andrew on "binding machines" (or alternatives)
>
>
> On Sun, 6 Oct 2002 10:35:29 -0600, "Ron Larson"
> <ronallarson@qwest.net> wrote:
>
> >Hi Andrew (cc stoves:

	<snip>


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