[Stoves] Rice husk stove and rice husk gasifier

Fri Oct 14 20:25:44 CDT 2016

Hi Bradnum

We developed the Mayon Turbo in the Philippines about 14 years ago. If built to specifications it works well especially for low income rural and peri-urban users. Peasants farmers called it the poor mans gas stove. 

All these rice husk stoves have advantages and disadvantages. What people liked about our stove was its low cost, profound simplicity and portability.  Farmers liked the ash as fertilizer and pest repellent. It does require someone regualrly tending the stove as paul said every 3-5 minutes and the ash is messy to clean out (we often set it into a half barrel). Batch stoves with fans are expensive and cooks often don't like the batch nature of the stove and power requirement. 

The bigger Mayon Turbo's have more autonomy and are less finicky to manage the fuel feeding and quality of combustion. However too big a stove and you have the risk of burning the rice from excess heat.  The problem is rice hull is a high ash fuel (20% ash) that has low density and is difficult to burn as the porosity of the fuel changes as it burns out. Hence you need to continual add new fuel and clear out the ashes. We did some experimental work with chopped grass stems that had low ash and we got much better autonomy. I dont think you can easily do better than our Mayon turbo 7000 or 7500 for autonomy and clean burn  without going to a batch forced air stove. The other challenge is fuelbed fires if the stove and fuel source get too hot. That was the main problem of designs we saw in the late 90's when we started.  

Its the combination  of low fuel density causing flow problems,  high ash fuel, changing porosity of the combustion bed, controlling air flow and fuelbed fires that make this not a simple design task. In essence it is an impossible dream that you can have near full autonomy like a wood stove without some frequent manual agitation (tapping every 3-5 minutes) without going the electrically powered forced air/fan approach.  We encouraged farmers also to just turn the surplus rice husk into a carbonized material with a home built carbonizer to create an amendment for Bokashi fertilizer production. 

You can read more on our MTS stove and our clay brick stove at www.reap-canada.com 

cheers
Roger Samson
www.reap-canada.com

--------------------------------------------
On Fri, 10/14/16, Ronal W. Larson <rongretlarson at comcast.net> wrote:

 Subject: Re: [Stoves] Rice husk stove and rice husk gasifier
 To: "Discussion of biomass" <stoves at lists.bioenergylists.org>
 Cc: marc at rvit.co
 Received: Friday, October 14, 2016, 2:35 PM

 Chris, cc
 List and Paul
 	To Paul’s list I would
 add the name of Paul Olivier.  He has some fine looking
 rice husk TLUDs that are built on Belonio principles.  All
 open source.
 	Contact information at http://www.esrla.com/
 Ron

 On
 Oct 14, 2016, at 11:24 AM, Paul Anderson <psanders at ilstu.edu>
 wrote:
 Chris,

 I was a univ. professor for 30 years,
 and I know a few things about student projects.  Great as
 learning experiences, and sometimes (seldom) a significant
 breakthrough will occur.   Best wishes to your student.
  I want to encourage stove work that is useful.  So I ask
 questions:

 1.  Why reject the use
 of a small fan or blower?  Just to make things harder to
 accomplish?  Or is it financial?  But fans and small
 amounts of electricity are inexpensive and easy to obtain,
 and give tremendous advantages for the stove user and for
 the likelyhood of success for a project.

 2.  Mayon Turbo:  natural draft.
  reputation of requiring the user to be nearby to
 frequently tap the side of the unit to get the husks to
 flow.   So, is "attention by the user to the stove
 operations" to be a factor in the stove design?

 3.  The world leader in rice husk
 gasification is Eng. Alexis Belonio.  See his writings
 (many are on my website  www.drtlud.com ).   Good
 science and good research starts with a thorough review of
 the literature.  Ask her:  "Has the literature been
 reviewed?"

 4.  Suggestion:
  Contact Marc Pare (see   http://rvit.co/ ).  About 5
 years ago as a student at Georgia Tech University he was on
 a student project specifically about rice husk gasification
 with natural draft for stoves.  Twice I visited the campus,
 student group, and met the professor.   No published
 report because the project was not successful (except as a
 great learning experience and course credit for the
 students.)  Marc went on to do larger gasification projects
 with rice husks in Vietnam.  And now his is an engineer in
 the Seattle area.   I am sending  him a copy of this
 message.

 Please keep us posted.

 Best wishes,

 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 10/14/2016 7:05 AM, Christopher
 Bradnum wrote:
 Dear List Member

 I am looking for some help on a
 project one of my students is starting.

 I have a Taiwanese student who would
 like to develop a passive (not electric fan) rice husk stove
 for her home as her major project for the BEng in Mechanical
 Engineering at the University of Nottingham. Depending on
 the success of the project, her family may consider starting
 a business manufacturing such stoves within their community.
 Her family own a rice farm and they have a lot of material
 that they can convert into energy. They already have a stove
 (sorry I don't have the photographs of this) which they
 use for some of their cooking needs. It has a deep central
 'pot like' component (+/- 750mm tall X 300mm
 diameter) with a grid at its base which holds the burning
 rice husk. This 'pot' is located inside a larger
 vessel. At the base a fan directs air in below the central
 rice burning 'pot'. A separate pot holder unit is
 placed on top of the whole configuration. This has, what
 looks like, an inverted colander at its centre through which
 the flame reaches the cooking pot. The stove
 The student returns home in December
 and will complete some rudimentary tests to get a baseline
 for the efficiency and emissions given off by the stove. I
 will also get her to complete the heterogeneous cooking test
 developed by SeTAR under Prof Harold Annegarn and Crispin
 Pemberton-Piggots' supervision at the University of
 Johannesburg.
 Leading
 up to that testing I want her to get on with a bit of
 research, so I thought to turn to this very excellent group
 and ask for some help (standing on the shoulders of
 giants...).
 Has anyone
 on the list worked with rice husk as a fuel source and does
 anyone have any research work we can look at as a starting
 point? Particularly using rice husks as a fuel for
 cooking.

 It seems to me, through
 superficial online perusing, that a rice husk gasifier might
 be a better utilisation of the raw material. If it is a good
 system to convert rice husk into energy I would like to make
 and test one of these too. Does anyone have research around
 rice husk gasifiers that I could start investigating? Is
 this a good or not so good use of the fuel?

 Kind regards

 Chris

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