[Stoves] ***SPAM*** Re: SPAM: ***SPAM*** Re: Design for a stove/heater for making biochar

[Paul Olivier]

Rice husks are a wonderful gasifier fuel.

On Thu, Feb 23, 2023 at 3:06 AM Tom Miles <tmiles at trmiles.com> wrote:

> Great suggestion. Thanks. I wondered if anyone had optimized the stove for
> combustion. Rice husks tend to smolder. Removing char faster than it is
> consumed has become a common way to make char. I like the adjustable gate
> and water quench.
>
> T R Miles Technical Consultants Inc.
> tmiles at trmiles.com
> Sent from mobile.
>
> > On Feb 22, 2023, at 1:40 PM, ajheggie at gmail.com wrote:
> >
> > Thanks for remembering the Mayon Turbo Stove Crispin, I was impressed
> > with it but it had slipped my mind.
> >
> > Andrew
> >
> >> On Wed, 22 Feb 2023 at 17:56, Crispin Pemberton-Pigott
> >> <crispinpigott at outlook.com> wrote:
> >>
> >> Dear Ashok
> >>
> >>
> >>
> >> There is a stove called the Mayon Turbo Stove designed by Roger Samson
> from REAP Canada in Montreal.  This stove has been made is multiple
> countries.  It is a rice hull gasifier.  It can cook one pot.  I suppose
> you could put an oven on top to bake.
> >>
> >>
> >>
> >> The relevance is that there is a cone-shaped fuel holder that is filled
> around the periphery with the flame burning in the centre, up a sort of
> short chimney. The fuel falls down the cone to reach choke point.  That
> choke point can be made larger, smaller or adjustable.
> >>
> >>
> >>
> >> When the rice hull gasifies, it becomes char.  As the char falls to the
> choke point, it can either fall out as char or be held for longer (because
> the choke is smaller) so it burns to ash. Your choice.  If you created an
> adjustable choke point, probably a flat round horizontal place attached to
> a central threaded bar, you could have different sorts of treatment (in
> terms of temperature) and different yield percentages.  The hot char falls
> out of the bottom onto the ground.  You could just as easily have it fall
> out into a shallow bucket of water.
> >>
> >>
> >>
> >> This is a very clean burning stove and runs well on rice hull which is
> often a poor cooking fuel.  It can be refuelled as you wish, which is
> unusual for a true biomass gasifier. You can reach Roger at
> rogerenroute at gmail.com.  I think he sells drawings or some such.  Not
> sure at the moment.  It has been around for a long time, originally used in
> the Philippines.
> >>
> >>
> >>
> >> I have worked on this stove with some of his interns to improve the
> heat transfer efficiency and fuel combustion %, not to make char but to
> burn the fuel more completely.   The idea of adjusting the outlet at the
> bottom to “tune for char” was not thought of at that time, but it was
> clearly an option.  It is important to know that the original design, which
> features a short air pipe or two, did not have the correct air supply and a
> considerable improvement was made by altering the size and placement of the
> cold air entry from below.  To optimise this you have to have a combustion
> analyser. If the drawings are from the 90’s, then this change has not been
> incorporated.   As I recall the original design has far too much air
> entering the pyrolysis zone so the gas exit temperature (impinging on the
> pot) was cooled by it.  The excess air level in a reasonable gasifier
> should be between 90% and 110% when building at the artisan level.
> >>
> >>
> >>
> >> You will see from the photos at the link above that it can be used tog
> gasify all manner of wood chips and agriwaste.
> >>
> >>
> >>
> >> Best regards
> >>
> >> Crispin
> >>
> >>
> >>
> >> New Dawn Engineering Inc
> >>
> >> Alberta
> >>
> >> Canada
> >>
> >> From: Stoves <stoves-bounces at lists.bioenergylists.org> On Behalf Of
> Ashok Mathur
> >> Sent: Tuesday, February 21, 2023 6:30
> >> To: Discussion of biomass cooking stoves <
> stoves at lists.bioenergylists.org>; ajheggie at gmail.com
> >> Subject: [Stoves] Design for a stove/heater for making biochar
> >>
> >>
> >>
> >> Dear All,
> >>
> >> This note is a slight deviation from the discussion on bio-char.
> >>
> >> Usually bio-char is made in drums that exclude air and are heated by
> electricity.
> >>
> >> Because of high capital costs and running costs, bio-char becomes
> uneconomical for farmers to use.
> >>
> >> Rice husk and rice straw are two materials that are freely available.
> They both can be used as the fuel to heat bio-char as well as the material
> that is pyrolyzed to make the bio-char.
> >>
> >> When they are coated with a slurry of sand and soil containing iron
> ore, they make a super bio-char for growing rice. There may be some
> disagreement with that statement but keep it aside for the moment. The ash
> produced is a good soil amendment.
> >>
> >> Has anybody designed/knows about an apparatus for producing bio-char
> using this material as a fuel and a substance to pyrolyze?
> >>
> >> Regards
> >>
> >> Ashok
> >>
> >> PS I am also looking for use of these materials to make baking ovens
> for biscuits and bread, flatbread etc.
> >>
> >>
> >>
> >> On Tuesday, February 21, 2023 at 05:34:37 PM GMT+5:30,
> ajheggie at gmail.com <ajheggie at gmail.com> wrote:
> >>
> >>
> >>
> >>
> >>
> >>> On Tue, 21 Feb 2023 at 03:06, Ronal Larson <rongretlarson at comcast.net>
> wrote:
> >>>
> >>> Although the term Pyrolysis used - and looks like a TLUd in some ways,
> there was zero mention of char.  I’m pretty sure all  the char was consumed
> - which is OK.  Much better than starting with char made badly, and he’s
> probably right he has a clean stove.
> >>
> >> Yes he definitely says it is burned out to ash, so the top down burn
> >> and the diffuse secondary flame will morph into an updraught charcoal
> >> burn until only ash remains. This is interesting  in itself as the
> >> char will be burning out  with a low superficial velocity of air and I
> >> wonder what the implications of carbon monoxide in the exhaust are if
> >> a secondary flame is not sustained in this second phase (and I don't
> >> believe it can be).
> >>
> >> It wouldn't be  that difficult to arrange for the air to be totally
> >> shut off when the pyrolysis front reached the bottom but this too may
> >> have implications for unburnt products at the end.
> >>
> >> Perceived wisdom is that to gasify the char in an updraught gasifier
> >> and  have a secondary flame of carbon monoxide would require ramping
> >> up the superficial velocity of the air, probably requiring a fan. This
> >> is normally avoided in TLUD devices because the temperature gets far
> >> too high for the container.
> >>>
> >>> The most interesting thing for me was the material seems to be a cast
> ceramic.
> >>
> >> Yes I didn't pick up on what was in the concrete mix but it would be
> >> something dense for it to function as a masonry stove, albeit top lit.
> >> Probably high alumina cement??
> >>
> >> I wonder if Norbert Senf is still reading here and would like to
> comment?
> >>
> >> Andrew
> >>
> >>
> >>
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-- 
Paul A. Olivier PhD
104/43 Phu Dong Thien Vuong
Dalat
Vietnam

Louisiana telephone: 1-337-447-4124 (rings Vietnam)
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