[Stoves] FW: A continuous feed rice husk gasifier for parboiling 40 kg of rice?

jed.building.bridges at gmail.com jed.building.bridges at gmail.com
Fri Feb 20 13:34:37 CST 2015


(The images in Joshua's original email were too large to go to the list. Attached are smaller copies of those files. - Erin R. erin at trmiles.com  ) 

 

From: Joshua Guinto [mailto:jed.building.bridges at gmail.com] 
Sent: Friday, February 20, 2015 2:25 AM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] A continuous feed rice husk gasifier for parboiling 40 kg of rice?

 

Dear Dr. Paul and Joe and Serge and everyone (sorry, i clicked the send icon before finishing the whole email.... )

Greetings!

This is also very interesting for me. As you know i was all the while tinkering with the terra cotta equivalents of the gasifier stoves. And i just have one on the making. For the lack of better name i call it the Brick Stove Carbonizer. 
 

Last night, i found a video in the you tube and it helped greatly to understand parboiling as this is the first time for me to learn about it. 

https://www.youtube.com/watch?v=bNUlsnIO_1A

My idea to combined the best features of five technological fronts for the need of Serge in parboiling: 

1. Stability  and Safety. The video portrays a huge metal pots (25 liters i suppose) and needs a stable base as the cook work in the rice and steam with the hot pot. The In Stove has this feature. 

2. Ease in Loading/Unloading: The challenge is how to bring the volatile gases down close to the ground so the stove and the big pot may sit at the comfortable reach of the cook. The height of the stove and the pot matters as the cook will be pouring rice, hauling them, setting the steamer and so on. Prof Alexis Belonio developed the rice husk gasifier stoves with the burners low on the ground. 

3. Time of Cooking: Parboiling takes several hours of different intensities and duration.Joe James is pushing up ahead with his JJQuad Stove and have great improvements in terms of extending the  burn time of the rice husk load. Going further Engr. Alexis Belonio has a rice husk gasifier that can run in a continuous mode. 

4. Mitigating Health Risks of the Nano Particles of Silica in Burning Rice Husks: Should we be concerned with sillicosis ? (respiratory ailment caused by the accumulation of silica in the lungs).

http://en.wikipedia.org/wiki/Silicosis

Mr. Neil Lumanlan, a professor of microbiology in the Philippines raised this issue more than once.. 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3606399/

http://www.nature.com/srep/2013/130529/srep01919/full/srep01919.html

 

A chimney for this is best portrayed by the In Stove or is it enough when handling rice husks? 

 

5.  Reducing the Cost and Extending the Usable Life of the Stove. At this moment, i am discovering the methods and techniques on how to make gasifiers in terra cotta equivalents. I have now fire bricks of different shapes which can be stacked like a Lego piece to form any structure. Following the recipe of low thermal mass clay, the  fire bricks float in water !! Thanks to Jon and Flip Anderson and Dr. Larry for the coaching. And then, when stacked together, they would form into a  gasifier stove that runs in TLUD mode. Tests are ongoing with rice husks, pine needles, saw dust, coco shells, canarium shells. Test last night with one kilogram of rice husk with a computer fan set at 4.5 volts boiled 5 liters of water in 19 minutes 10 seconds. My thanks also goes to Dr. TLUD for the lessons during the Stove Camp 2014 in Aprovecho. 

With the gasifier built from terra cotta, the cost of the entire stove can drop to a minimum and can be built into almost any shape. It may also be combined with metal. to undertake the components such as the pot rest, the gas pipes, the burner and so on. 

I also believe that brick pieces can be made to create the terra cotta equivalent of the In Stove as well as the  continuous rice husk gasifier of Engr Belonio and then fitted with a chimney and a fan. 

Is pottery a tradition in Serge's place in Benin? 

 

As there are yet so many things unknown with this prototype, please allow me to tinker with it further and make my mistakes on my safe space with the help of small circle of friends. I will surely let everyone know the progress very soon. 

Best wishes

Jed Guinto

 

Joshua B. Guinto
Specialist, Appropriate Technology

MSc Management of AgroEcological Knowledge and Social Change (MAKS)

Wageningen University, The Netherlands 




Joshua B. Guinto
Specialist, Appropriate Technology

MSc Management of AgroEcological Knowledge and Social Change (MAKS)

Wageningen University, The Netherlands 

 

2015-02-20 3:10 GMT+08:00 Paul Anderson <psanders at ilstu.edu>:

Dear Serge and Abraham,

I am not sure in what country Abraham lives.   Please tell us. It is interesting that two messages about parboiling of rice arrived so close together in time.

The rest of this message relates to Serge's message:

1.  Please confirm the following:
A.  The people who parboil the rice are doing it as a business.
B.  Do those same people remove the husks from the barboiled rice?   If yes, then they have control over their own fuel supply, which is good.

C.  The rice must reach a temperature of 80 deg C.   But how critical is it that the time to reach that temperature is about 30 minutes?   What if it took 45 minutes?   or only 20 minutes? Does that have any impact on the rice itself?

D.  How do the people know that it has reached about 80 C? Thermometer?   Visual seeing of small bubbles rising?   Touch? That does not make any difference.   I am just curious.

E.  The steaming of the hot wet rice is the crucial step.   We will try for boiling (evaporating away) 6 L of water in one hour.   But how sensitive is that time?    And if the time needs to be close to one hour, and if the stove is boiling away the water too fast, is it acceptable to have 7 or 8 liters for creation of the steam.   In other words, steam (at 100 deg C) needs to pass through the rice.   Is the amount of steam (from 6 liters of water) the important issue, or is steam for one hour (whether from 6 or 7 or 8 liters) the important issue?

2.  Joe James (who is receiving this message) has recently worked on a rice husk TLUD gasifier that should be able to accomplish the specified tasks.   Joe is an engineer and can crank out some of the numbers.   Also some other members of this Stoves Listserv could be of assistance.  Here are the questions:
How much heat is needed to vaporize 6 L of water?
Raise 6000 g of water from about 25 C to 100 C
(75 degree change x _______ Joules per gram x 6000 = ___________)
Then add in the latent heat needed for vaporizing the 6000 g.

Divide that total amount of heat by 60 minutes.

Determine how much rice husk is needed to get the needed heat (allow for efficiency of heat transfer to be as low as 30%.)

This not my specialty, but I know it all can be calculated.   Also to calculate the heat needed to bring the pot to 80 deg C in the first phase of the processing.  A little assistance would be appreciated.

Then we see how much heat Joe's unit (called JJQuad TLUD) can put out.   The unit can be made larger or smaller, and having 2 units might be the better option.   Or we increase the air flow (via the fan) to get faster pyrolysis, and maybe we need to have a refill of fuel into the batch gasifier.   This does not take long to refill and reignite.

3.  Subject to actually making things happen, in my opinion the best "evident" option is to have a rice husk gasifier provide the heat by using the husks from the rice as fuel for the parboiling businesses are creating.

4.  The production of at JJQuad TLUD is being examined in Vietnam at this time.   We are assisted with this by Dylan Maxwell and Olivier Kolmel, who are also receiving this message.  There are issues being examined about fans and controls and metal quality and production.   This is not a quick solution, but it is quite viable, in my opinion.

5.  Serge, I would like to know about the number of parboiled-rice producers you are considering could need such a solution.   Also, please tell us about metal working (thin sheet metal) capabilities in Benin, and accessible.  Also, I would appreciate information about you and your involvement and situation (with an NGO?).

It might be time for this conversation to not be on the Stove Listserv, or after any replies by Joe or Dylan and Olivier.   Any readers who have continuing interest should probably tell me and Serge so that we can keep you informed.

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype: paultlud      Phone: +1-309-452-7072 <tel:%2B1-309-452-7072> 
Website:  www.drtlud.com

On 2/19/2015 5:21 AM, Serge Horsmans wrote:

Dear Paul and ,

Thank you very much for your quick response.  Please find the answers
to the questions asked.

1.  How important is it to convert to using the rice husks as fuel for
the parboiling process?   I believe that use of the rice husk as fuel
is NOT the priority.   As Serge and Abraham have stated, the main
concern is to reduce the use of large amounts of wood.   Appropriately
sized TLUD gasifiers with wood fuel (or Rocket burners of sticks)
could accomplish the task of reducing the amount of wood being burned.
   This would be with natural draft.

At this moment I have to list the possibilities of not using firewood
in the parboiling process.   The use of a rice husk gasifier seems to
me one of those possibilities.  So I would like to continue with rice
husk, as it is easily available.  So at this moment I would like to
answer the question, “Is somebody using a rice husk gasifier that that
can heat water to a temperature of about 80°C in about 30 min.?  And
can the same stove be used to boil away 6 l. of water In about 1 h.?”.
If there is such a stove I would like to know and I will added to my
list.  Next we might want to test that one first.

2.  IF rice husks are to be used with a TLUD gasfier, it would
required Force Air (or Fan Assistance) (FA), and that would require a
small amount of electricity.   With the parboiling being done in the
daytime, a solar cell could be used, even without a battery.   What
are the availabilities of small electrical power in the locations of
either Abraham's or Serge's operations?

I was aware that fan assistance would be needed.  We do have the
possibility to provide the required electricity.

3.  Please comment on the frequency of doing the parboiling task.
Abraham, is your operation run every day?   Frequency of use can
impact favorably the ability of maintain equipment such as a fan unit
or battery / solar package.

Maintenance will not be a problem.

4.  For the 25 L quantities described by Serge, there is really no
need to have a continuous operating gasifier.   Either the unit could
be large enough for the stated durations of usage (30 minutes to raise
to 80 C; and one hour for the steaming).   To boil away (evaporate) 6
L of water in one hour can be accomplished; but some attention should
be paid to the configuration under the pot, such as possibly having a
pot-skirt or other ways to improve heat retention and heat transfer.
This is NOT a situation requiring a good turn down ratio to obtain Low
Power cooking.

We will use the configuration you can see on the pictures where the
rice is steamed or use a pot skirt.  We might not need a continuous
operating gasifier but as the operations will be performed outdoor,
wind or other environmental factors might slow down the heating,
requiring more fuel.  What ever type we will use, we need to make sure
that the parboiling can be finished.  The aim of our study is to
improve the livelihood of the rice parboilers in Benin.  If the
parboiling process cannot be finished, the paddy might get spoiled and
they will not have an income, they will loose the money they used to
buy the paddy instead.  That should be avoided.   So if we go on with
batch gasifiers, we might have to oversize the unit.

5.  As we close in on the topic, we need to discuss who will lead the
efforts (management) to accomplish the tasks, and who will pay for the
expenses (finances).    Strong communications via email are quite
important.  Skype is useful.   Access to some sheet-metal workers is
important for the fabrication of the TLUDs.   The cost of materials
should not be very high, but the issues and costs of management and
labor can be easy or difficult, depending on the circumstances.

It is going very fast now and I 'm very happy with your enthusiasm !
But as you can read in the answer on your first question, right now I
am listing the possibilities of not using firewood in the parboiling
process.  So my first question is, can we banish firewood using those
stoves?  Or more in detail, I want to know “Is there an existing rice
husk gasifier that that can heat water to a temperature of about 80°C
in about 30 min.?  And can the same stove be used to boil away 6 l. of
water In about 1 h.?”.     If there is not such a stove, we will have
to compare  the different  possibilities to banish firewood in the
parboiling of rice in Benin.  The rice husk gasifiers will be an
option.  Next we might consider to design one ourselves and your help
will be really appreciated.  As we have experience in Benin with
dissemination of new technologies, we might start to built them and
provide them.  But we are not that far yet.

6.  Are Serge and Abraham close together, and working together?    If
not, each should describe their specific situations.    Please send us
your views of possible plans for moving forward.

I would like to know more about Abraham and his project.   As
mentioned we are in Benin and at the moment I live in Savalou,
department Les Collines.  For my view, please read my answer on
question 5.  I like to know more about your views.

Thank you very much!

Kind regards,

Serge

2015-02-18 19:30 GMT+01:00, Paul Anderson <psanders at ilstu.edu>:

Dear Serge and Abraham,

The photos from Serge are very helpful.   Photos from Abraham will show
the larger system that they use.

There are a few questions and issues.

1.  How important is it to convert to using the rice husks as fuel for
the parboiling process?   I believe that use of the rice husk as fuel is
NOT the priority.   As Serge and Abraham have stated, the main concern
is to reduce the use of large amounts of wood. Appropriately sized TLUD
gasifiers with wood fuel (or Rocket burners of sticks) could accomplish
the task of reducing the amount of wood being burned.   This would be
with natural draft.

2. _IF _rice husks are to be used with a TLUD gasfier, it would required
Force Air (or Fan Assistance) (FA), and that would require a small
amount of electricity.   With the parboiling being done in the daytime,
a solar cell could be used, even without a battery.   What are the
availabilities of small electrical power in the locations of either
Abraham's or Serge's operations?

3.  Please comment on the frequency of doing the parboiling task.
Abraham, is your operation run every day?   Frequency of use can impact
favorably the ability of maintain equipment such as a fan unit or
battery / solar package.

4.  For the 25 L quantities described by Serge, there is really no need
to have a continuous operating gasifier.   Either the unit could be
large enough for the stated durations of usage (30 minutes to raise to
80 C; and one hour for the steaming).   To boil away (evaporate) 6 L of
water in one hour can be accomplished; but some attention should be paid
to the configuration under the pot, such as possibly having a pot-skirt
or other ways to improve heat retention and heat transfer.   This is NOT
a situation requiring a good turn down ratio to obtain Low Power cooking.

5.  As we close in on the topic, we need to discuss who will lead the
efforts (management) to accomplish the tasks, and who will pay for the
expenses (finances).    Strong communications via email are quite
important.  Skype is useful.   Access to some sheet-metal workers is
important for the fabrication of the TLUDs.   The cost of materials
should not be very high, but the issues and costs of management and
labor can be easy or difficult, depending on the circumstances.

6.  Are Serge and Abraham close together, and working together? If not,
each should describe their specific situations.    Please send us your
views of possible plans for moving forward.

 

Dr TLUD

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype: paultlud      Phone: +1-309-452-7072 <tel:%2B1-309-452-7072> 
Website:  www.drtlud.com

On 2/18/2015 5:01 AM, Serge Horsmans wrote:

Dear Paul (and other insiders),

thank you very much for your attention to my request.  Below you will
find the questions and the answers.  Please ask for more information
if needed.

1.  What heat source(s) are you currently using?   Do you have
batch-operations of rice husk gasifiers already?   What is good and
what is bad about them?

   At the moment we are using fire wood as the heat source.  We are not
using gasifiers and I don't have any experience with them, but it
seems to me that continuous flow gasifiers are more appropriate since
once the heating of the soak water or the steaming is started, it
should not be interrupted by refilling the batch.  It is hard to find
gasifiers in Africa.

2.  Is your operation the only one, or could there be other similar
businesses that might also want to improve their heat sources?

   I am not too much aware of the other businesses, but it is easy to
guess that if it is affordable technology, it will as well be adopted
by local restaurants.  For one or other reason this technology didn't
reach Africa yet.
In Benin, it is mainly women that parboil rice.   Recently a new
device for parboiling has been introduced to improve the quality of
the parboiled rice.  An educational video, in which rural women
   explain how to use the improved rice-parboiling technology and its
benefits, was
   developed by AfricaRice in 2005 to promote this technology to
end-users.  The video-supported training tool has contributed
significantly to the
   diffusion of the technology in Central Benin. This video has been
used by many NGOs. It is now the common device in Benin. So the same
might be done with the gasifier.  All organisations that support those
women might adopt the gasifiers as they all want to reduce the use of
fire wood.

3.  I assume that all of the associated structures are in place,
functional, and are expected to be part of the new operation.
Structures such as the large vessels (pots, trays, cauldrons, etc.)
and also the boiler.

Yes, though I don't know what you mean about the boiler... it is just
wood placed below the cauldron  .
Any heat source that can be used to heat water in a cauldron could be
used as the device is basically a cauldron containing about 25 l. of
water for soaking the paddy.   The same cauldron is afterwards used
for steaming the paddy with about 6l. of water ( I will add some
pictures).  Since firewood and charcoal have always been used and is
easily available, they continue to use firewood or charcoal.   By
introducing the gasifiers we would like to reduce the use of firewood.
- Soaking process:  heat paddy in 25 l. of water to a temperature of
about 80°C, it takes about 30 min.   Next let it cool down during the
night in the cauldron.
- Steaming process:   You take a paddy holding vat and a cauldron (a
similar cauldron as for the soaking). The  paddy holding vat is
perforated with holes (maximum diameter 2.5 mm) from its base to about
a quarter
   of the way up its body . The paddy rice is poured into
   the vat, which is inserted in the cauldron containing 6l. of water.
The water level in
   the cauldron is such that it does not reach the bottom of the paddy
holding vat.  The improved
   method prevents water in the cauldron from getting into the paddy,
only the steam
   generated from the boiling water in the cauldron passes through the
perforated vat to
   parboil (steam) the paddy rice.  It takes about 1 hour.

4.  Please send us some photos of the existing installation. There are
issues such as height of the boiler above ground that can influence
what options could be for the new "fire box."

I will add some.  Please ask for more if needed.

5.  Are you or others in your area interested in biochar from the rice
husks?   If so, a pyrolyzer (rather than a full process gasifier)
might be more appropriate.

Hard to say.  The women parboiling the rice are not same as the ones
cultivating the rice.   So they will not use the biochar as a soil
conditioner.  I have no clear idea what could be done with biochar...

Thanks again  for your attention to my request.   I 'm looking forward
to hear from you again.

Kind regards,

Serge



 



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