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

[Smail Khennas <smailk@itdg.org.uk>]

Dear all
Slight correction due to a typing mistake in the figures given by Fernando
one US$  = 27 CUP (cuban pesos) and not the other way. Fernando may confirm
and explain the sublities of exchange rates in Cuba

Smail
-----Original Message-----
From: Fernando Martirena [mailto:f.martirena@enet.cu]
Sent: 09 October 2002 23:11
To: Ron Larson; stoves@crest.org
Cc: Smail Khennas; Kurt Rhyner Pozak; Tom Miles
Subject: Re: Forwarding Prof. Matirena on briquette work in Cuba and
"binders"


Dear Ron!

Thanks for your interesting comments. I'm already in the list so I'm posting
this message directly on it.

As to your interesting points:

> (RWL1):  On your slide 6 - you have used the term "pozzolanic" and shown a
> graph of "poszzolanic activity index" (up to 80 units) vs pozzolanic
> content (fractions of a gram).  I do not recall ever seeing this term on
our
> list (or even heard it).  My dictionary equates this to volcanic ashes -
> used in the manufacture of hydraulic cement.  Are you in someway capturing
> the ash content from the bricks you produce and then using this in the
> cement industry - or is this a way only of describing the nature of the
ash
> content of your brick?  If the latter, can you describe what is good or
bad
> about the various samples you show for bagasse, rice husks, etc?

I have been working with pozzolanic binders made out of agri-industrial
wastes since 1992. We have developed an appropriate technology for the
manufacture of a lime-pozzolana binder at a very small scale (for further
details see www.ecosur.org ). The results of this work are already
disseminated in Cuba and many countries in Central America. The research
work can be divided into three main parts:

1. Use of non-treated pozzolanic ashes (1992-1995): we simply picked the
sugar cane (or rice husk) ashes burnt in the boiler or directly on the open
air and used them as source of pozzolana. The pozzolana is a mineral rich in
alumina and silica that combined with lime in a moist environment when
finely ground reacts as a hydraulic binder similar to Portland cement
although with lower strength. The main problem associated to non-treated ash
for the high temperature to which they were subjected (over 900 Celsius)
which led to a crystalline structure most likely non-reactive.

2. Use of treated pozzolanic ash (1995-1998): we picked the biomass before
it was burnt and burnt it in special incinerators at controlled temperature
and residence time with the aim of improving the reactivity of the ash. This
really gave a very reactive pozzolana, however the ash output of the
incinerator was not as high as expected, and the whole industrial process
was not energy efficient at all, since the low burning temperature at the
incinerator did not allow heat recovery facilities, and thus most of the
combustion heat had to be released to the atmosphere.

3. Use of what we name after "enhanced pozzolana" (1998-2002): bearing in
mind the need to have a more efficient process, we explored the possibility
to raise the burning temperature of the biomass. This gave birth to the
concept of the "Solid Fuel Block", whereas burnable biomass and clay are
mixed together and pressed. The fuel can be burnt at higher temperatures,
thus allowing improved energy efficiency. The block was composed of
approximately 20% clay and 80% biomass, with 10% moisture. The clay gets
thermally activated at temperatures between 800-1000 Celsius, thus becoming
a very reactive pozzolana. The clay has low ignition losses (IL) and thus
remains almost intact after burning, although more reactive. The biomass,
however, burns completely, and only approximately 10% of the initial weight
remains as ash that is very non-reactive because of the high burning
temperatures. The resulting SFB ash has then approximately 80% activated
clay and 20% non-reactive biomass ash. It has proven to be a super pozzolana

The stage 3 prolonged itself into a separate study for the development of
fuel, basically linked to the manufacture of building materials with
appropriate technologies. This means -as you hinted- that the brick or lime
producer can capture his ash and sell it to the cement manufacturer, who
will then receive a very reactive (and cheap) raw material.

The Solid Fuel Block itself is a technology for the processing of wastes
into a useful fuel, and therefore can be used alone, for instance, for
cooking facilities, for bakeries, etc. At the moment our workshop is tapping
a great demand from restaurants and hospitals, whose cooking facilities are
prepared only to burn the scarce firewood.  We are not, however, sure that
the SFB ashes resulting from using the fuel for cooking -because of the
relatively low temperatures- could be as reactive as the one resulting from
lime or fire clay bricks manufacture.

(RWL2):  You show prices or costs like .09 and .13 for one brick.  Are
> these Euros?

These are Cuban pesos (CUP). One CUP equals to $27 USD. However I would not
recommend extrapolating these figures to other countries, since the Cuban
economy has very special aspects, which you do not find in other countries.

> (RWL3):  Have you ever considered using holes in
> the brick to assist in ignition?  Could you describe your ignition
process.

Yes we have. At the beginning we used the CINVA RAM press, which presses
blocks with holes inside, however it did not work as expected, basically
because the device to insert the holes puts a limit to the piston moving
downwards, and ofeten this prevents us from achieving the needed pressure,
which results in a less dense and thus bad brick.

(RWL3):This looks like a brick that would be pretty hard to ignite -
> because of its quite large size.

We thought the same at the beginning, but we had no choice since the only
press available had only this kind of brick mold. Also we were concerned
about the high clay content of our briquette, which could likely turn up in
more smoke emission at burning. The first tests cleared our doubts: the
bricks burnt very well, they just burst into flames, and made less smoke in
comparison with the firewood currently used. The block burnt longer than
pieces of firewood of similar size, and the heat produced was more
consistent. We videotaped everything, made interviews with the workers at
the local kitchen where it was tested and they all preferred the SFB against
the firewood.

>How about cylindrical rather than brick forms?

We are exploring new and more productive presses, where we are also thinking
of cylindrical forms. In two months we will have our first prototype of the
new press in operation.

(RWL4)  You show (p9) one graph of O2 content from 19 to 20% - which I
> would consider a high excess air ratio  (as a function of air temperatures
> from 100 to 140 C - which I consider low).  Could you describe something
> more of both the stove/apparatus in which this data was taken - and the
> measurement apparatus used?  (we have had much recent discussion about
> measurement equipment)

Yes, indeed, the O2 content shows a high excess air ratio. This is because
of the stove where it was tested, a very rudimentary one, whose burning
chamber is not properly sealed and therefore there was no way to control
airflow.

The test was contracted to a R&D center in our University. They used the
following equipment:

- Exhaust gas analyzer ORSAT: it allows the simultaneous análisis of oxygen,
carbon dioxide and monoxide

- Exhaust gas analyzer RBR - ECOM - SG PLUS: it allows the simultaneous
análisis of oxygen, carbon dioxide and monoxide; nitric oxides, sulfur
dioxide, room temperature and gas temperature, and combustion efficiency.

- Digital thermometer Kane Maye to measure gas temperature separately.

RWL:  We look forward to anything more you can tell us about your own work
> in Cuba - which I have only begun to describe.  Others who are interested
in
> this can do one of three things:  a) write you, b) write me, or c) wait
for
> Tom Miles to place on our archives.  Those on this list with a special
> interest in briquettes include Richard Stanley, Elsen Karstad, AD Karve,
> Crispin P-P, Paul Anderson, and a few others  - so I hope they will
> especially comment on the various topics that they will not yet have been
> able to see.

Thanks a lot for the reception to my explanation. I am happy to see that our
work has raised interest among all of you and look forward to keeping in
touch. I'm already on the "stoves" list, so I'll keep being posted.

Saludos, Fernando


----- Original Message -----
From: "Ron Larson" <ronallarson@qwest.net>
To: "Fernando Martirena" <f.martirena@enet.cu>; <stoves@crest.org>
Cc: "Smail Khennas" <Smailk@ITDG.org.uk>; <arconsult@cwcom.net>; "Kurt
Rhyner Pozak" <sofonias@compuserve.com>; "Tom Miles" <tmiles@trmiles.com>
Sent: Tuesday, October 08, 2002 4:03 PM
Subject: RE: Forwarding Prof. Matirena on briquette work in Cuba and
"binders"


> Fernando:
>
> As before I am forwarding this to "stoves" - as you must be a member to
> submit - and I only received this one copy.
>
> To keep the message short, I am taking the liberty of "cropping" (another
> funny double-meaning word)- and then adding a few more comments to yours
> after having received your nice power point message (the one Tom will
post):
>
> -----Original Message-----
> From: Fernando Martirena [mailto:f.martirena@enet.cu]
> Sent: Tuesday, October 08, 2002 7:31 AM
> To: Ron Larson; stoves@crest.org
> Cc: Smail Khennas; arconsult@cwcom.net; Kurt Rhyner Pozak
> Subject: Re: Forwarding Prof. Matirena on briquette work in Cuba and
> "binders"
>
>
> Hi Ron!
>
> Thanks for your prompt reply to my message. I am very glad that the
comments
> were of interest to you, and also thank you for forwarding this to the
list.
>
> I have already sent to you some material referring to the work that we
have
> done in the subject "biomass briquetting". If you are interested in
further
> (deeper) technical information, just let me know.
>
> (RWL):  Yes please send anything additional you have.  You are right on
> target for many "stoves" list members.  On the excellent power point
> material you have already sent (and which Tom Miles has said he will post
> after returning from Bangkok)- I have these additional questions:)
>
> (RWL1):  On your slide 6 - you have used the term "pozzolanic" and shown a
> graph of "poszzolanic activity index" (up to 80 units) vs pozzolanic
> content(fractions of a gram).  I do not recall ever seeing this term on
our
> list (or even heard it).  My dictionary equates this to volcanic ashes -
> used in the manufacture of hydraulic cement.  Are you in someway capturing
> the ash content from the bricks you produce and then using this in the
> cement industry - or is this a way only of describing the nature of the
ash
> content of your brick?  If the latter, can you describe what is good or
bad
> about the various samples you show for bagasse, rice husks, etc?
>
> (RWL2):  You show prices or costs like .09 and .13 for one brick.  Are
> these Euros?
>
> (RWL3):  This looks like a brick that would be pretty hard to ignite -
> because of its quite large size.  Have you ever considered using holes in
> the brick to assist in ignition?  Could you describe your ignition
process.
> How about cylindrical rather than brick forms?
>
> (RWL4)  You show (p9) one graph of O2 content from 19 to 20% - which I
> would consider a high excess air ratio  (as a function of air temperatures
> from 100 to 140 C - which I consider low).  Could you describe something
> more of both the stove/apparatus in which this data was taken - and the
> measurement apparatus used?  (we have had much recent discussion about
> measurement equipment)
>
> fernando said in closing his new introduction (and inserts on two more
> messages also follow):
>
> "Please have a look at my insertions below
>
> greetings, fernando"
>
> ----- Original Message -----
> From: "Ron Larson" <ronallarson@qwest.net>
> To: "Fernando Martirena" <f.martirena@enet.cu>; <stoves@crest.org>
> Cc: "Smail Khennas" <Smailk@ITDG.org.uk>; <arconsult@cwcom.net>
> Sent: Tuesday, October 08, 2002 12:52 AM
> Subject: Forwarding Prof. Matirena on briquette work in Cuba and "binders"
>
>
> > 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.
>
> I'm very happy about that as I said before
>
> > 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?)
>
> It's sometimes funny the winding ways to which language can lead us...  I
> think, however that you picked the right word for what you wanted to
> describe.
>
> >
> > -----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:
> >
> <snip>
>
> (RWL5):  You said this time after my comment about "ECOSUR":
>
> "ECOSUR/ECOSOUTH is an international network led by the NGO "Grupo
> Sofonias",
> who has been over 20 years working on development projects. It gathers
> organizations througout Latin America and Africa, and its main aim is the
> dissemination of information about building technologies and related
> subjects, like in this case stoves and fuel alternatives. Thay have an
> interesting stoves project in Ecuador. For further information you can
> contact Prof. Kurt Rhyner, President of grupo Sofonias and Chairman of the
> network."
>
> (RWL6):  Like yours, this message is also going to Professor Rhyner - so I
> hope he can also tell us more about Grupo Sofonias.  You said after my
> comment on seeing a brick manufacturer at WSSD:
>
> "Yes, we are simply using the existing stock of technology to manufacture
> another very different product: a solid fuel block. Sawdust has given us
one
> of our best results, although there are other interesting sources of waste
> biomass, such as sugar cane straw and bagasse, banana leaves, coffee
husks,
> etc. The disadvantage of the latter is that they should be shredded in
order
> to make them suitable for compaction. This means extra costs and some
waste
> of time."
>
> (RWL7):  See my first remarks about other shapes.  You then said that you
> had sent other material - which this list knows from a reply message from
> Tom Miles.  Then you said after my concluding comment:
> "Thanks for your attention, and look forward to keeping in contact"
>
> fernando
>
> RWL:  We look forward to anything more you can tell us about your own work
> in Cuba - which I have only begun to describe.  Others who are interested
in
> this can do one of three things:  a) write you, b) write me, or c) wait
for
> Tom Miles to place on our archives.  Those on this list with a special
> interest in briquettes include Richard Stanley, Elsen Karstad, AD Karve,
> Crispin P-P, Paul Anderson, and a few others  - so I hope they will
> especially comment on the various topics that they will not yet have been
> able to see.
>


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