[Stoves] Rice husk stove and rice husk gasifier
Roger Samson
rogerenroute at yahoo.ca
Mon Oct 17 12:30:36 CDT 2016
Hi Christopher
One thing I forgot to mention is that the frequent tending (every 3-5 minutes) was not that problematic for countries that had fairly quick (eg 25-30 minute) cooking cycles like the Philippines. In West Africa, households were often 15 in number and they had much larger pots and longer cooking cycles (1hr+). The West African women already were overburdened so the rice hull stove just added another job to the day. In West Africa the MTS was mostly used for food reheating and short cooking cycle foods. In Senegal and Gambia we ended up inventing the REAP clay brick stove where it reduced cooking cycles and womens labour burden. It is my preferred stove for that region of West Africa as it is so cheap to build with local materials, very safe with the large pots, safes fuel and reduces cooking cycles. You can also use it outdoors in rural areas with a roof (taking stoves outdoors is the most profoundly simple and effective strategy to solve the indoor air quality problem).
http://www.reap-canada.com/online_library/IntDev/Brochure%20-%20REAP%20Noflay%20Clay%20Brick%20Stove.pdf
We had quite a bit of time to work on designing the MTS in the field in the rural Philippines as we had a fairly large grant on climate change mitigation using household cookstoves as a mitigation strategy in 2000. We also had 6 engineering student interns periodically work on the stove after that initial project. They were especially helpful in streamlining manufacturing methods. Several other outside stove engineers have tried to make improvements by adding features to marginally improve the combustion/convenience but what we ended up with was a more expensive and difficult stove to build and operate. In the end we just left the stove as is, as adding new features didn't appear viable for the rural market. A marginal efficiency improvement is not worthwhile if it comes at a cost as the stove largely has a free fuel. We can produce a blue flame from the rice hull with no fan for about $15-$20 depending on the region. The main point is that rice hull is not a rich mans fuel as its such a low quality bulky fuel that is full of ash. You can't over design stoves for poor people. The main problem we had is that workshops that had the capacity to build the stove often dropped it because it wasn't lucrative enough. Lower capacity workshops often had problems building it to the design specifications so we ended up making jigs to help improve quality control. Making a more complication version of the MTS is just going to make it more out of reach for the poor and the ability to find viable workshops to build it. Our goal in our stove designs for poor folks is to aim for profound simplicity and keep the stove affordable.
If anyone is interested to buy the MTS stove rights from us, REAP-Canada we would be open to that. We aren't working as much on stoves at the moment as donors seem to have lost their way by focusing on household cookstoves with confusing complexity of design that are unaffordable for the rural poor. We presently sell the stove design patterns through a manufacturing stove production licence for $200.
Most recently REAP-Canada has been working on biomass grass breeding in Canada and our agroecological village international development programs. Internationally I really like the idea of growing grasses and shredding them and using the stems as fuel and the leaves as fodder. Grass stems when properly sized can create a rice hull like porosity to make a really nice fuel for the MTS. Grass stems have about 2% ash versus 25% for rice hull. I would like to work on that project further.
best regards
Roger Samson
Executive Director
REAP-CANADA
www.reap-canada.com
--------------------------------------------
On Mon, 10/17/16, Christopher Bradnum <Christopher.Bradnum at nottingham.ac.uk> wrote:
Subject: Re: [Stoves] Rice husk stove and rice husk gasifier
To: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Received: Monday, October 17, 2016, 10:23 AM
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Dear Ken, Paul, Ronal and
Roger,
Thank you for the links and
details. I will ask the student to get on with the research.
I too will start looking at the literature
available and be in a better position to advise
her.
I don’t expect any major
breakthroughs as she is a third year student, but as with
all work in this area, an incremental improvement
can move the conversation forward.
Roger, the Mayon Turbo Stove looks
really impressive, she will definitely need to start her
investigations there.
Excluding the fan was her
suggestion, but this really is the earliest possible stage
of the project and we will need to be more open
minded about what needs to be included or excluded, thanks
Paul.
As we get on with the development
work I will ask her to show her results to this
forum.
Thank you all again, kind
regards
Chris
From: Stoves
[mailto:stoves-bounces at lists.bioenergylists.org]
On Behalf Of Ken Boak
Sent: 14 October 2016 14:28
To: Discussion of biomass cooking stoves
<stoves at lists.bioenergylists.org>
Subject: Re: [Stoves] Rice husk stove and rice husk
gasifier
Chris & List
modern experience of rice
husk gasification - a paper from 2014
https://halshs.archives-ouvertes.fr/hal-01107615/document
plus a link to an old
paper with some information on rice husk gasification
https://books.google.co.uk/books?id=JKty_OlU8bEC&pg=PA12&dq=gemcor+rice+husk+gasifiers&hl=en&sa=X&ved=0ahUKEwjYr8bAsdrPAhVBKsAKHbnhBbIQ6AEIHjAA#v=onepage&q=gemcor%20rice%20husk%20gasifiers&f=false
On 14 October 2016 at
13:05, Christopher Bradnum <Christopher.Bradnum at nottingham.ac.uk>
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 complete
is around 1,000mm tall. The
rice husk is top lit inside the central pot and I assume
the air pushed in from underneath helps to fuel the fire.
The stove produces a reddish / purple flame and I am told a
pot filled with fuel lasts for 5 hours. Although I can't
quite work out what needs
to be cooked for that long.
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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