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

[Paul Anderson]

Serge,

We seem to be making progress.

Please note that there can be more than one RH gasifier under the pot if 
more heat is needed.   But this would be done only if attempts to make 
the gasifier larger are not successful.   The 25 liter pots are not so 
large as to cause difficulties to get sufficient heat within the 
preferred times for heating to 80 C and for the steaming.  The current 
Rua units and the JJQuad unit can possibly do the task already (to be 
determined by testing).

If there is an issue of height of the total operation because of the 
need to place a gasifier under the pot, the height can be addressed with 
a short platform for the workers to stand upon. Alternatively, the 
gasifier could be in a sufficiently large depression.

Also, because we are using forced air (fan assistance), it is possible 
to draw (pull) the pyrolytic gases so that they exit from the side of 
the gasifier (not yet mixed with air, so they are not burning), and then 
direct those gases laterally or even slightly downward so that the fire 
is under the pot.  This is actually easier to do in larger TLUDs than in 
the small ones that are most known.

We all need to appreciate that Serge's first step is to make a report 
that might name a TLUD-FA-RH (TLUD with fan assistance for rice husk 
fuel) as a technology to be considered.   And then there needs to be a 
decision to proceed.   So this is not a simple "quick fix" that is being 
proposed for immediate testing in the villages in Benin.   There is an 
opportunity to conduct testing elsewhere.

Serge, we need some additional information.   The pot size is said to be 
25 Liter (actually a little larger so that the 25 L can enter into the 
pot.   Please confirm that those are cast iron pot.   Are any other 
types of pots in use?   Would any other pots be considered or even 
encouraged?

In many African countries there is fabrication of stainless steel 
cooking pots for institutional cooking.  Are any of those being 
fabricated in Benin?  If the fabrication skills are available, the SS 
pots could be made in any desired size and shape.

Also, in Benin, is there any tendency that the parboiling operations are 
becoming larger (such as one location processing two of the 25 Liter 
batches) or more consolidated for greater volume of production?    Or 
for using any larger pots?

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 2/21/2015 2:13 AM, Serge Horsmans wrote:
> Dear Mr. Anderson, Guinto and other insiders,
>
> Thank you very much for your reply.
> This section  relates to Mr. Anderson's message, in the next section I
> have some questions and answers for Mr. Guinto.
>
> I 'm subscribed to the Stoves Listserv. So I will from now on only
> send mail to the Stoves Listserv.
> We are making progress.
>
> 1) We will want to make sure that the parboiler people retain
> ownership of the rice husks.   Husks are now probably being thrown
> away.   But if the husks have some value, ownership can become an
> issue.   At least the amount of husks for the parboiling operations.
> Any surplus husks might be marketed by the miller if and when there
> are other rice-husk gasifier stoves in the area.
>
> I am aware that ownership of rice husk might become an issue if the
> stove becomes a success in Benin but that is hard to predict.  ThoughI
> think at this moment this should not be considered yet because my job
> right now is to examine the possibilities to banish the use of
> firewood in the parboiling process in Benin.  So at this stage the use
> of a rice husk gasifier is just an attractive option.    It seemed to
> me that the stoves are proven technology for preparing meals. Since
> the parboiling of rice has some similarities with the preparation of
> food, I wanted to know more about the stoves.  To me the most
> important differences seem to be the 'scale' of the stove like the
> diameter of the gasifier stove
>   reactor and the size of the unit containing the rice husk. That is
> why I subscribed to the Stoves Listserv to meet the experts.
>
> 2) You showed that supply of metal is available.   Now we need to
> determine if there are appropriate metal working shops or craftsmen.
> It will be best when we have a unit that can be seen and copied in
> Benin.   Please tell me if VECO would take on the initial efforts to
> put together the "package" that includes getting the equipment,
> initial experimentation (so that there is an "expert" in the
> organization), demonstrations, support for initial users, and record
> keeping with feedback to everyone involved.   And is the key person
> you?
>
> At this stage it is not my intention to mobilize the means to to put
> together the "package".  Currently I am making a report about the
> possibilities to banish firewood in the parboiling process in Benin.
> The rice husk gasifiers might be a topic in my report.  We will
> consider the different possibilities to banish firewood in the
> parboiling process and their feasibility in Benin and rice husk
> gasifiers seem to be one possibility amongst others.   Only if the
> rice husk gasifier seems to be the best option and are retained to
> give it a try, we might consider to put together a "package".
>
> 3) We will probably be wanting to have initial units come from Hua
> community in Vietnam.   We await comments from Dylan M. and Olivier K.
>
> I am really looking forward to their comments.
>
> 4) The weather is so cold here in Illinois, USA, that I am not doing
> any experiments of my own right now.
>
> It is very kind of you to consider doing some experiments.
>
> 5) We have not yet had a reply from someone with the calculations that
> were previously discussed.   We will get that done eventually.
>
> 6) You need to give thought to the power supply for the fan that is
> needed in each of the RH gasifiers.   We usually utilize 12 volt DC
> power and fans.   Barely a few watts are needed for the duration of
> the gasification.
>
> It seems to me we might start with similar ones if RH are retained as
> a solution to banish firewood in the parboiling process in Benin.
>
> This section relates to Mr. Guinto's message,
>
> 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.
>
> Could you provide more information about the ”In Stove”?  Is it proven
> technology?  Could it be easily extended to be used in th eparboiling
> process as I described earlier?
>
> 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.
>
> Tthe 'cook' doesn't have to pour.   The cauldron and the paddy holding
> vat are a closed system to keep the steam inside.
>
> 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.
>
> In Benin, the parboiling process takes about one hour using firewood.
> If it would take hours the gasifier is no longer an interesting option
> because after parboiling we should be able to dry the parboiled paddy
> in the sun as long as possible.
>
> 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).
>
> The parboiling is done in open air, but a chimney might solve this
>
> 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.
>
> If possible, I would like to consider proven technology which might be
> extended to be useful in parboiling by for instance rescaling the
> device and other adaptations.
> 6. Is pottery a tradition in Serge's place in Benin?
>
> Yes.  In Benin here are even traditional stoves made of clay.
>
> 7.  Do you live in the Netherlands?  Next month I will be in Belgium,
> a neighbor of the Netherlands.
>
> Kindest regards,
>
> Serge
>
>
>