[Stoves] Dung Rocket Stove - Failed Test

Kevin McLean kevin at sun24.org
Sun Jan 15 18:43:57 CST 2023


Also, Crispin.  Have you tested anything related to top-lit bundles in
bands?

On Sun, Jan 15, 2023 at 4:49 PM Kevin McLean <kevin at sun24.org> wrote:

> Crispin,
>
> In high Mongolia, no crops or vegetables are grown so there is no need for
> fertilizer or biochar as a soil amendment, correct?
>
> On Sun, Jan 15, 2023 at 4:13 PM Crispin Pemberton-Pigott <
> crispinpigott at outlook.com> wrote:
>
>> Dear Ron and All
>>
>>
>>
>> I will consolidate several message responses.
>>
>>
>>
>> > a.  We’d rather not cook with dung at all  (agreeing with Paul Olivier
>> below).
>>
>>
>>
>> There are a number of places where dung is used because it can he
>> accessed “in house” for example in a crowded urban area without access to
>> purchased fuels.  The cow does the energy collection during the day and
>> provides it free to the family.  It is not only where alternative fuels are
>> absent.  If it is free and convenient, people use it.
>>
>>
>>
>> Just because fuel is free doesn’t mean it has to be burned badly.  Just
>> because a fuel is burned badly doesn’t mean it cannot be burned cleanly.
>> Just because a fuel could make biochar doesn’t mean it is wise to do so.
>>
>>
>>
>> > b.  We think making char apt to be cleaner and good for soil, but
>> carbon dioxide removal (CDR) may also mean one can make money while
>> cooking.  Might also save time for the cooks.
>>
>>
>>
>> Many people have no soil, and cannot grow anything in the soil they have
>> access to.  This is generally true for all high altitude locations where
>> dung burning in a rural area is widespread. Such areas include the whole of
>> the northern and southern Himalayas.  In the Pamir of Tajikistan, if you do
>> not burn dung, you die.
>>
>>
>>
>> > c.   We are unaware of any char-making stoves using dung (because dung
>> is so non-dense - need a lot more volume.)
>>
>>
>>
>> This is a good point. If you have to collect and (usually) process the
>> dung, the resulting fuel is not very energy dense, meaning available
>> MJ/kg.  Plus it is not dense kg/m3.  If you are creating char from a low
>> energy fuel, it is not wise in terms of effort.  If you only get 1/3 of the
>> available energy because the rest is tied up in char, you will have to
>> collect 3 times are much fuel.  Who is going to do that?!  People are not
>> crazy.
>>
>>
>>
>> > 5.  Other:
>>
>>                    a.  Anyone think that the present users of
>> dung-burning stoves in Mongolia and similar would surely or not-at-all
>> welcome such a stove?
>>
>>
>>
>> The photo Paul sent of a “dung burning stove” shown a box with a chimney
>> – typical of all Mongolian local baseline products.  There is nothing
>> “dung-burning” about the design.  They are typically made from 2mm steel
>> sheet and are good space heaters – with wood or dung.  As wood burners they
>> tend to be pretty good, but they are terrible coal stoves which is the
>> preferred urban fuel.
>>
>>
>>
>> A reasonably designed dung-burning stove such as the KG2.5
>> <http://www.newdawnengineering.com/website/library/Stoves/Kyrgyzstan/KG%20Model2.5/>
>> produced in Bishkek has staged combustion and the ability to cook at least
>> two pots – water heating being a major need.  Stoves, when not cooking, are
>> often heating 3 containers of water.
>>
>>
>>
>> > Anyone able to confirm those are from horses?  Maybe Yaks?   If
>> guaranteed to be horse dung, then we don’t need zoos.
>>
>>
>>
>> Dung source depends of geography and climate.   Yaks can live on very
>> poor grasses (like bison) and excrete modestly sized pellets. Bigger than a
>> horse (“road apples”) and much smaller than cattle.  In the high cold
>> regions, dung dries rapidly however it is often collected, wetted, and
>> mixed with chopped grass, for instance in southern Tibet.  The reason is an
>> absolute scarcity of fuel.  If they were to make char, they would freeze
>> due to lack of energy.
>>
>>
>>
>> > There is not much wood to burn in Mongolia.
>>
>>
>>
>> There is a massive amount of wood to burn in Mongolia, depending on where
>> you are of course.  North of Ulaanbaatar there are huge forests.  The
>> sawmills create enormous piles of sawdust which, when the market conditions
>> are right, is made into wood pellets or briquettes.  But only some.  Most
>> is too far away to complete with chopped and split wood.  I estimate thar
>> the population of UB burns more than 100,000 tons of wood each winter.  It
>> is a preferred summer time fuel, where the stove is removed to be used
>> outdoors (because it overheats the yurt).
>>
>>
>>
>> > Wow. 2 billion dung-stove  users!.  I had not been paying attention to
>> the large number combusting dung  -  and do agree we should be trying to
>> improve its combustion in cookstoves.   It might even be possible to make
>> them fairly clean.
>>
>>
>>
>> Of course it is.  Burning low density fuels (not only dung) requires
>> particular air control and grate bar spacing.  It has very light ash so if
>> the fuel is burned completely, it has rather a lot of fine white ash which
>> can be lofted easily.  That needs consideration.
>>
>>
>>
>> >But I think it much better to promote a switch to charcoal-making
>> stoves.   Not just for dung, but for every fuel.
>>
>>
>>
>> It is OK to think that, just don’t expect people to act on it.  Doing so
>> for most dung burning region would impose a huge additional labour-burden
>> on women, in particular.  Gender rights advocates should rise up as One to
>> protest any plan to enforce dung-burning char-making stoves on anyone.
>>
>>
>>
>> >And we need urgently to be practicing carbon dioxide removal (CDR).
>>
>>
>>
>> You want the energy-poorest people in the world to get involved in CO2
>> removal?  How more anti-poor can a policy possibly be?
>>
>>
>>
>> > 3.   Re TLUDs and dung, I found TLIUD support in this 2014 non-fee
>> paper:    A Biochar-producing, Dung-burning Cookstove for Humanitarian
>> Purposes
>>
>>
>>
>> “Humanitarian”? How more anti-poor could a proposal be?  Go to southern
>> Tibet.  Altitude, 16,000 ft.  Nothing except grass and the occasional
>> rhododendron can grow there. Either you live on animal products, or
>> imported food, or you die.  No one is going to waste 2/3 of their available
>> energy supply to appease rich, Western climate fanatics.
>>
>>
>>
>> > Cooking with dung is exceptionally dirty.
>>
>> Nonsense.  Cooking with a stove not designed for dung is “dirty”.
>>
>>
>>
>> > I'm working with a group that is trying to slow glacial melt in the
>> Himalayas.
>>
>>
>>
>> Then develop a clear burning stove combustor, and while you are at it,
>> make it more thermally efficient so the mass needed per winter is reduced
>> by, say, 50%.
>>
>>
>>
>> >And I agree that it would be best if everyone used cooking methods that
>> are cleaner than burning dung.
>>
>>
>>
>> I pressure you have never seen a good dung burning stoves.  There is no
>> “dirt” in dung. There is no “smoke”.  Smoke is produced by stoves not
>> burning it properly.
>>
>>
>>
>> >Dung is not a good fuel.
>>
>>
>>
>> Second opinion: Dung is a good fuel. Most stoves that burn it (not all)
>> are absolute crap.
>>
>>
>>
>> >Today we tested a dung rocket stove.  I'm a little surprised that the
>> test was a failure.  Can anyone suggest changes?
>>
>>
>>
>> This is a big ask. An whole theory of combustion is needed to address the
>> matter.  The consolidation of the dung into a large single mass cause a lot
>> of the problems. That is not how to prepare dung.  A great deal can be
>> learned by observing people who use it.  Here is a Tajik dung burning stove
>> loaded before ignition:
>>
>>
>>
>>
>>
>> Note the large pieces of wood used to establish a hot coal bed.  Once it
>> is going well, the fire will be pushed to the far end of the chamber and
>> new fuel added at the door. No fuel is placed on top of a going fire.  This
>> arrangement is very clean burning.
>>
>>
>>
>> This lady was involved in stove promotion for three years before seeing
>> this simple, locally designed dung burning stove.  She tried it and said it
>> was the first time in three years of promoting ISC that the “was excited”
>> about a stove.
>>
>>
>>
>>
>>
>> The combustion is at the back under the big pot.  The water warming is at
>> the front, not at the back, and it was very clean burning – even though at
>> this time the design was primitive.  The KG2.5 came after 3 years of
>> further development and is significantly more efficient, cleaner burning
>> and burns for far longer on a load of fuel.
>>
>>
>>
>> This is dung preparation in rural Tajikistan:
>>
>>
>>
>> This is one of several typical preparations. The diameter is about 5
>> inches.  The format suits poorly designed stoves with high excess air.
>>
>>
>>
>> This is Umedjani Kurbon, aged 12, who is the operator of the CNC plasma
>> cutter.  He got the responsibility because he could read and do simple
>> arithmetic.  He had never received any instructions on how to use it
>> properly.  If you zoom the screen, you can see the standard shapes from
>> which to select a cut.  They owned no computer on which they could to
>> prepare whole parts. This gives you an idea of the conditions in which
>> producers live.
>>
>>
>>
>> >The fire was never strong and there was a lot of smoke.
>>
>>
>>
>> This is not surprising because, with good intentions, you were guessing.
>> Now you know several things not to do. It might have done better if it have
>> been dried at 105 C for a couple of days.  But I doubt it. It has to have a
>> certain surface-to-volume ratio and controlled primary air to burn
>> cleanly.  The total surface burning at any one time sets the firepower.  If
>> you break each piece of fuel in half, it will increase the gasification
>> (devolatilisation) rate.  A certain primary air flow is required for each
>> surface area burn, and a separate secondary air flow is needed that relates
>> to that gasification rate. You should aim for an oxygen concentration of
>> 10% in the exhaust.
>>
>>
>>
>> Good luck!
>>
>> Crispin
>>
>>
>>
>>
>>
>> Crispin Pemberton-Pigott
>>
>>
>>
>> New Dawn Engineering Inc.
>>
>> P.O. Box 3
>>
>> Alberta Beach, Alberta
>>
>> Canada T0E 0A0
>>
>> www.newdawnengineering.com
>>
>>
>>
>> Research & Design Office
>>
>> 5011 Crestview Drive
>>
>> Val Quentin , Alberta
>>
>> Canada, T0E 0A0
>>
>> +1-519-886-7772
>>
>>
>>
>> Mobile
>>
>> Canada +1-519-729-3442 + WhatsApp + WeChat
>>
>>
>>
>> Email: crispinpigott at outlook.com
>>
>> crispin at newdawnengineering.com
>>
>>
>>
>>
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