Improved Biomass Cooking Stoves

We are trying to (a) reduce the amount of emmisisons from charcoal production and (b) Condense and recover as much of the smoke into a usable product for your home/farm. Wood tar - the following is an explanation from the good folks at Food and Agriculture Organization of the United Nations (FAO) about what is going on in this process.
"The non-water component consists of wood tars, both water soluble and insoluble, acetic acid, methanol, acetone and other complex chemicals in small amounts. If left to stand, the proligneous acid separates into two layers comprising the water insoluble tar and a watery layer containing the remaining chemicals. Recovery of the water insoluble tar, often called wood or Stockholm tar, is simple - it is merely decanted from the water phase. This wood tar has uses as a veterinary antiseptic, a preservative for wood, a caulking agent, and as a substitute for road tar" http://www.fao.org/docrep/x5328e/x5328e0d.htm

For more pictures click here

Notes from Ed:

Hi sorry I havn't been following all of this thread, but I thought this might be of interest to somebody,

I am a market gardener, I produce a steady stream of biochar from my water heating systems. I live in Wales, it is cold and wet here and I like washing in hot water.

I have played with bringing tlud stoves indoors but it is not easy and so I have built water heating systems using what I call biochar rocket stoves (sorry if this brings back bad memories Crispin!)
Because they are not filled, lit and emptied from the top they can easily be left in place under heat exchangers, hot plates and a flue outlet pipe. Here in Wales this is important.
If you run them in the evening, when you most need space heat and cooking, then after a couple of hours you have your biochar. It is fine to keep them burning for as long as you want (whereas there is a limit to how much you can keep topping up a tlud)
Unlike wood burning stoves, it is possible to have the flue outlet angled up about 30 degrees from horizontal and surrounded in a thermal mass to capture residual heat. Otherwise the 8th photo is of a section of flue outlet with integral thermal mass.
Shut a door on the front and the biochar goes out overnight. My CO meter has yet to read 1ppm indoors. Empty the biochar by sliding out the floor of the stove and it drops straight into a metal bucket, no quenching, no dust and no mess.
The first photos are of these stoves connected to a 50 litre water tank + hotplate and oven for cooking. (The pipe in the second picture is to give secondary air to the flames.) The system in these photos is mobile and connected to a small header tank so that I can do demos at permaculture conventions and workshops.
The youtube video link below is of something different; a double walled flue pipe with feed and empty hoppers for putting in biomass and emptying out biochar. A bit like an anila stove except the inner combustion pipe has no floor, it goes straight through to the stove below. If its ok with Crispin, I was thinking of calling this flue pipe an anila flue pipe.

http://youtu.be/MTiSTrdYuoA

Lighting Cones can help make traditional and charcoal stoves light more efficiently and with less smoke than other lighting methods. For the best detail, download the Masters thesis pdf from Kathleen Lask

From Crispin Pemberton-Pigott's Description:

"The main principle is that there should be enough draft to light the fire rapidly. The lighting cone provides this if it is about 500mm tall."

"The second principle is that the bottom of the cone should sort of cover the lighting fuels so that most air is pulled from below, not from the side."

"The third principle is that if there is a secondary air supply at of just below the top of the fuel, the bottom of the cone should bypass it so that the heat inside the cone is not used to pull air through the secondary air ports. Very few stoves have a secondary air controller."

In the result with good fit: "You can just see on the left that it bypasses the secondary and draws all air from below, through the fuel – in this case charcoal. Peter Coughlin reports it reduces the charcoal ignition time by more than ½. We will quantify the smoke reduction and GERES way independently confirm it at some point – it is about 90%."

Lighting stoves can also be used with traditional fires. In tests lighting damp wood in Suba Island "The speed of ignition and reduction in smoke was dramatic. You can just see the hot air distortion of the picture above the cone – basically no smoke. It is quite a bit cleaner than the fire when lit and the cone removed."
The cone on the 3 stone fire is 125

The Stove in the top example is an Anglo Supra Nova.
"It was developed at YDD during the World Bank/Indonesian Clean Stove Initiative."

"It as an Anglo Supra with preheated secondary air. It can burn wood or charcoal, and it can burn wood pellets in TLUD mode. It can automatically switch from pellet burning TLUD pyrolyser mode to char-burning mode by using a disc of paper on top of the grate."

"The loose piece of clay is a door which can close the primary air without affect the secondary air. It provides a significant level of power control without adding or removing fuel. The heat transfer efficiency burning charcoal (it is nominally a charcoal stove) is about 50%. It Is portable with handles and sells retail for about $5.50."

Kathleen’s investigation is attached.

Regards
Crispin

Joshua B. Guinto in the Phillippines used the Oblak Holey Roket stove as inspiration and created a stove with an extra compartment to store char until cooking is done and the char is sufficiently cooled. He has done a wonderful job of writing up the results in the attached pdf.
From his conclusion:
The Charmaking Stove is Born!

• The Char Making Holey Roket Stove is born!!
• It allows harvesting bio char safely and conveniently and without having to tip the stove over. It eliminates the risk of heat fatigue, burns and open fires.
• It allows clean cooking with the similar performance as a gasifier stove.
• It allows continuous cooking.
• The stove will last for four years or more.
• It can be used with many other kinds of fuels.
• The stove is much cheaper and can be fabricated in village workshops thus promotes social inclusion much better.
• With clay, the stove has very small ecological footprint.

Air Force 1 Sage Low

Marc Pare has a been keeping notes on his attempts to solve the problems of burning rice hulls in household cooking stoves in his rice husk design log: http://ricehusk.cc/goodboiler/

In it, he goes back to the beginning of 'stove'-ness and introduces design and prototyping concepts as well as giving his test results.

Check it out. Shop Sneakers in Footwear

The Quad TLUD has features for easier production (using tabs and slots, and zero rivets), easier shipping (as flat-pack pieces), local assembly, and greater stability and coolness of four wooden handles that serve also as legs. Without question, there will be further improvements as the number of users increases and they provide feedback. For example, households using the Quad TLUD stoves in various refugee camps could make suggestions that outsiders might fail to foresee. Jigs, tools and methods for making flat-pack pieces are being prepared in the USA for availability to stove projects worldwide.

Material: Sheet metal and 4 wooden handles/legs

Cost: Mwoto and Quad TLUDs sell for approximately US$15 in Uganda, and should eventually cost less, especially if purchased in bulk as flat-pack pieces to be assembled by a local project.

Dimensions: Currently one size, but size can be easily changed: Height: 19” (48 cm), Square footprint 12 x 12” (300 x 300 mm); Fuel cylinder height 14 “ (36 cm) with diameters from 5 to 7” (12 to 18 cm).
Test results of Quad and closely related TLUD stoves such as Mwoto and Champion:

CO & PM Emissions: Consistently the lowest for any of the natural draft stoves that burn solid biomass.

Thermal efficiency: Range from 35% to 41% currently. Expected to go even higher.

Fuel consumption: 1050 to 1600 grams for a standard WBT of cold start plus simmer (respectably low).

Fuel types: TLUDs can utilize a wide variety of low-value chunky dry biomass fuels (e.g. corncobs, tree seed pods, nut shells), including briquette pieces that can be locally produced from unused biomass. “Stick-wood” is not a common TLUD fuel, but can be used vertically as “wood segments.” Vertical segments also with papyrus reeds, bamboo, etc.
Options: The Quad can be made as a TChar variation for ease of using the created charcoal as fuel in a charcoal stove or as biochar that is added to the soil.

Hi friends,

I have reported to many of you how fun and successful my cooking demonstration with Dr. Paul
Olivier's rusk husk burning TLUD was on my 1st day back in San Jose. My thanks again to friend and frequent SeaChar volunteer Birgit Lendernick for hosting and organizing that. So fun, great food, great conversations and the stove's clean blue flame impressed everyone there
It has been an absolutely exhilarating ten days, since my MEPE bus rolled into Puerto Viejo. Yesterday E.F. promoter, Thierry Mangel and I conducted a biochar buy-back day in the Bribri communities of Amubri, Suiri and Sueretka. We worked closely with the organizers in each community and although it involved lifting and transferring approx. 1200 lbs of biochar from homes to truck, to boat, back to truck and then off-loading. It went great, everyone coordinated well. After stopping at APPTA to pick up the last 10 sacks of biochar that we had inventoried there. We off-loaded and dry stored 565 kilograms in 54 sacks. This gives us enough to meet the order which we have received from a researcher at CORBANA. http://translate.google.com/translate?hl=en&sl=es&u=http://www.corbana.c...

CORBANA is the research and farmer education arm of the Costa Rican Banana industry. They have one of the most sophisticated soil testing laboratories in the country. They will be initiating a three year long controlled study program evaluating the use of biochar on banana cultivation and field practices. This will be the 1st of several orders as this program gets underway. We will enjoy full access to the data from the project as this very important relationship develops. As I have said recently I am not so impressed with how much more biochar we have been selling this year as I am by how influential some of the parties buying it are.

The grass tablet biochar (pyrolytic carbon) shown above was made in an iCan TLUD
with a variable speed blower. This charcoal was air quenched and is thus bone dry.
When wet, it is very soft and can be formed to fit a variety of shapes. I have found, for
example, that grass tablet biochar saturated with cold water is effective at reducing the
pain of burns.

The following pages illustrate some of the ways the above biochar was made.
Note: Grass biochar will be ashy as grass has considerably more ash content that
wood

Grass tablets broken into short sections prior to being loaded into the fuel chamber of
the iCan reactor.
These tablets were made from field grass about 3 years ago in Shelburne, VT. Note
that the longest fibers are about the length of the diameter of the tablet. Shorter is
better.
These tablets are about 4 cm in diameter.

Download the attached Grass Tablet Biochar How To for detailed Reactor photographs and answers to questions posed to Jock by the stoves community.

Shop: Nike

Attached are the trials i did with biochar from rice husks and vermicast. I mixed the two together and filled the containers to become my garden.

Some of the lessons i learned

1. vermicast is highly water soluble and quick releasing than compost. Therefore i had to sprinkle a scoop of the vermicast once every week.

2. The vermi cast - biochar mix need a curing time before it can support the plants. Beneficial microorganisms can help cure the mix.

3. The earthworms take up a considerable amount of nutrients from the compost to become their body tissues.

And then do you think we can use the biochar-vermicast mix into the floating gardens? They are much lighter.

Good luck with your project.

Jed

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