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

[Joshua Guinto]

Dear Dr. Paul and Joe and Serge.

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 four technological fronts for the
need of Serge in parboiling:






*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
> 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
>>> 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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