Metal

Crispin Pemberton-Piggot and Roger Samson, January 2010

Grasifier

Roger Samson was here tonight and we made and tested a Grasifier: a Switchgrass burning stove based on the dimensions of the Vesto adapted to make a lower cost pellet burning stove for Haiti.

Power, 2.5 kw
Burn rate 8-10 g/min
Mass 550 g
Fuel load 600 g though it can hold 750

Lighted with two caps of paint thinners
The flame went completely blue (just before the end) then wobbled a lot and went out.
When it went out there was no smoke indicating there were no volatiles left.

Time to fabricate, about 30 minutes.

I see this as a burner that can be attached to the centre of a Haitian charcoal stove to convert it into very clean burning a pellet stove.

Char yield: 25% of the initial dry mass.
Moisture content of the initial fuel, about 7%

Ash: nearly none.

Nat Mulcahy, January 2010

Spent the day yesterday working with the state department to get more clearance for our shipments. 64 tons of pellets will provide food and clean water for 145000 families.

with 3,000,000 people displaced it will not last long. we are handing our the pellets and peanut shells in paper bags we have measured out to cook one meal or boil three pots of water. the paper bags are about the size one a lunch bag and the bag itself is the tinder to start the stove.

Spend the past two days working with NIH, EPA, The State Department, Haiti, USAID, and the World Bank. LuciaStove production is now set at 3000 per month but we keep being asked to ramp up to 5 to10 times that number.
Today we started casting the larger parts for the Biucci (the institutional version of the LucieStove), see attached. The more we make in haiti the more jobs we create here and the less we have to depend on the very sporadic shipping options.

Fuel, Stoves and Water for Haiti
January 27, 2009

There are several projects to supply fuel, stoves and potable water to Haiti. Some have been been ongoing since before the quake and some. The organizations we know of are:

CHF International, Helps (Water Purifier)
To donate a $35 water purifying system, go to https://secure.helpsintl.org/store/haiti.php

Legacy Foundation (Fuel Briquettes)

Miombo, Project Haiti www.prohaiti.org
Peko Pe TLUD pellet fueled stoves to be distributed by Project Haiti. Pellets from Georgia.

Trees, Water, People TWP
Ananda Marga Universal Relief Team AMURT http://www.amurthaiti.org/ and
Recho Rocket stove made from mud formed in a bucket, the Haiti Rocket Stove
Stovetec Rocket Stoves in a metal bucket.

World Stove, International Lifeline Fund
Biucci, Everything Nice TLUD stoves fabricated in Haiti. Pellet fuel from Florida (Green Circle). Grass pellets to be made in Haiti.

Apparently Discontinued:
MIT D Lab, Charcoal from Corn Cobs and Sugar Cane Waste

Martin Boll, January, 2010

Take a normal 870ml (fruit-) can, cut with a sharp-edged knife parallel cuts in the bottom with about 5mm distance.

1.-Bend with a screw-driver and pliers the metal-ribbons to get a grate.
This alone works well, but looses some fuel/charcoal.

2.- Form a “plissee”-metal-sheet (pleated) out of the side of a (10cm
diameter) can.

Each zig-zag-side about 1cm. The angles 60°. Put the can with slits ( like
1.-) onto the plisse-grate/support, so that the slits cross the plies in 90°.

-The plissee-lines are directed in wind-direction.

-The ashes on the pleated-metal-sheet can be cleaned with a thin stick or wire, while burning; but caution, that the tin-can-stove does not tumble.

-Another advantage of the plissee is, that the grat/bottom is heat-isolating and protected by the ashes. The charcoal falling through the upper gate is burning on the ashes on the plissee.

A CLEAN BURNING COOKSTOVE DEVELOPED IN VIETNAM
Alexis Belonio, Tran Binh, Doan Thi Minh Nguyet, and Bui Dinh Hai
VINASILIC SJ, Socialist Republic of Vietnam and Center for Rice Husk Energy,
Philippines January 24, 2010

Nathaniel Mulcahy, January 2010

Attached are the photos of Mr. Ronald Watts' version of our EverythingNice Stove. A version of which we are now rushing for the Haitian relief efforts to provide clean water. More later

yours, Nat

--
Dear Nathaniel

Here a a few photos from the successful construction and operation of the stove. Because I had no suitable vessels, I built them from sheet steel. It operates quite well, and is a good prototype for a larger model

Many thanks
Ronald Watts

Bjarne Laustsen, January 2010

Jiko Mbono is Swahili for Jatropha Stove.

Jiko Mbono was developed for burning whole Jatropha seeds.
The stove is a TLUD (Top-Lit UpDraft) gasification stove with natural draft air supply.

Earlier development of Jatropha stoves have mainly been based on the use of Jatropha oil. But the use of Jatropha oil in stoves have had some problems. In wick stoves the problem have been on the high viscosity of the oil which makes it difficult to climb wick to feed the flame, this has caused the wick material to burn. Jatropha pressurised stoves have also the problems of keeping the nozzles clean, and also the complicated design which tends to make the stoves relative expensive.

I therefore got the idea to burn the seeds directly in the stove. If the gasification process could provide the heat in the stove to vaporize out the oil from the seeds in the form of gasses, that will save us the work of first mechanically pressing the oil out of the seeds.

I therefore started some experimentation with some simple stove design, and these first experiments showed that it was possible to burn the whole seeds in a stove. Further developments was however needed to get an efficient and user friendly design of the stove.

I contacted Dr. Hassan M. Rajabu from College of Engineering & Technology at University of Dar es Salaam so that we could further develop the stove and test the stove after each modification. In this development we have received valuable economical support from the US based organisation Partners for Development and also support from Pamoja INC. Engineer F. Lauwo from Tanzania Engineering and Manufacturing Design Organisation (TEMDO) have provided assistance in producing the prototypes of the stoves.

Diagram of Jiko Mbono.

The fire in the stove is normally started by having a few crushed seeds that are soaked in methylated spirit or kerosene. These crushed seeds are placed at the top of other seeds in the fuelbox and the fire is lit in these crushed seeds.
The initial process can be started inside the stove or outside. When some seeds at the top got good flames (3-5 minutes) the fuelbox is then placed on the shelve at the bottom of the stove door and the door is closed so the fuelbox get into its position in the centre of the stove. In this initial phase the primary air is kept fully open.

The pyrolysis of the seeds by supply of primary air will gradually build up and the gasses from the pyrolysis will raise by the draft from the stoves internal chimney and be burned at the top by mixing with the secondary air.

During this gradually build up of heat the primary air supply need to be reduced such that enough secondary air can be supplied to allow for a good combustion of the gasses.

The burning of the Jatropha seeds is undertaken in batch portions. After all the seeds in the fuelbox have been pyrolysis the fuelbox need to be taken out and refilled for a new burning. It is not possible at this stage of the development of the stove to refill the fuelbox when the stove is operating, such refilling will just results in heavy smoke.

With a full load of fuel 300 – 400 gram of Jatropha seeds the stove can burn for 1 to 1½ hour when used in real cooking where the fire is somehow turned down. During test we have recorded specific fuel consumption on around 52 gram seeds per liter of boiling water, and an energy efficiency around 44%. However, the high efficiency is atributed to the design of the top part of the stove where the top is inserted in a skirt.

When operated properly the carbon in the seeds will remain as some kind of charcoal.

The use of renewable fuel is important here in Tanzania, where most of the biomass fuels are harvested in natural forests which takes year to re-grow.
We have estimated that a household having 200 – 300 meters of hedges of Jatropha trees will be able to meet their own need of fuel for the household cooking. Jatropha is often planted as hedges, it is a good hedge plant, as it is not browsed by goats, cows or other animals. Also as a hedge plant it does not compete with food crops on cultivating areas.

For urban households in Tanzania Jatropha is a viable alternative to charcoal. A farmer here gets 150 Tsh for one kg of Jatropha seeds (exchange rate 1350 to $). In town the Jatropha seeds will sell for around 300 sh. An urban household will need around 2 kg seeds per day to meet their energy need for cooking, that gives a monthly energy bill of 18,000 sh. If the same households are using charcoal it will on average consume 3 bags of 30 kg charcoal of a price of not less than 15,000 sh, this gives a monthly energy bill of minimum 45,000 sh. The use of Jatropha will in this way represent a good saving and alternative to fuelwood and charcoal.

Other seeds and crop wates can also be used in the stove. We know that seeds from the Croton tree burns well so does Castor seeds. We have also tried and found that the shells from cashew nut burn well in the stove. These shells are mainly a waste product from small-scale Cashew nut processing plants which are scattered in regions growing cashew trees.. We also believe that other seeds such as the oil palm kernel could also burn well when cracked a little. There will likely be many other oil holding seeds that could be used in such a stove.

This is a three-part brief description of the World Stove Everything Nice stove made by Al Hislop and Patty Roberts, with Ron Larson participating in the first tests, January, 2010.

World Everything Nice Stove
Plans Available at: http://worldstove.com/wp-content/uploads/2009/11/EverythingNice_Stove_Instructions.pdf

Part A. Narrative (by Patty)

Biochar Experiment 1 1/9/10

Al made an Everything Nice pyrolyzer from the design on the World Stove website. We used a large coffee can and then a canister for the two cans so it was rather large. We first tried pine cones but they just smoked so we put in pellets instead. This gave a good clean burn and we put a tripod over the stove and boiled water, heated soup, cooked pasta and cooked pasta sauce with fresh meat and fresh vegetables. When the flame extinguished, there was still some smoke coming from the stove so it was covered on the top to remove oxygen and set in a shallow basin of water on the bottom. This extinguished the smoke but moistened the bottom of the char slightly. When we emptied the stove, we saw that some of the pellets had not pyrolyzed. We believe this was because of the fairly large diameter of the can. To dry the char and pyrolyze the remaining pellets, we put the mass into a canister and put it into our hot wood stove. This allowed complete pyrolysis of the remaining pellets and provided complete drying of the fuel. It’s possible that this changed the pH of the char from its original pH because of a different pyrolysis temperature.

Ignition: torch (for several minutes)

Pre-burn Fuel Weight: 58.5 oz wood pellets from 100% pine, less than 1% ash

Post-burn Fuel Weight (Char): 16.5 oz (28.2% of starting weight)

Post-burn Fuel Volume: Slightly greater than half of pre-burn volume

Time: 2 hours and 20 minutes of a very good, clean, strong burn.

Calculated output to pot: 560 watts

Exp1: (Saturday)
Lighting: See text. Hope others can tell us of their successful
ways to light this same stove. We have not yet tried to solve this
problem using prepared starter materials. Maybe easier with the
"restriction-lid" removed? The two sheet metal wind-breaks and the ice
show this was not the best day for testing. Note the small amount of
discoloration (burned paint on the lid) - from an earlier test with
too-loose material (that was easier to light), which only gets a little
larger in later photos.. Discoloration off-centered because of windy
conditions and means of lighting. When we got it started with this
torch, there was never any massive smoking.

Experiment 1, Good Flame

Good flame. A typical flame without a cook-pot. We saw essentially
the same flame for a total of more than 4 hours over two experiments.
The gap-reducing bricks not in place in this early photo. The
discoloration of the lid never got much more pronounced than here -
showing that a relatively cool gas is coming up in the outer narrow
"chimney". You can't see it here - but there are hot gases going down
through the central can fuel supply - doing the pyrolysis without
oxygen. We are unsure whether any pyrolysis gas is coming upwards
(we don't understand the pressure profiles yet), but certainly a good bit
is going downward. This is the best view of the outer set of large
holes. Could they be done with a punch? Maybe. Could they be
placed on the bottom of the outer can? Maybe - with a spacer
between the bottom surfaces of the two “cans” (as is done in the
mainWorld Stove models). There are several ways
possible to control this air supply - which should NOT be called the
primary air, as would be appropriate if this were a TLUD. Although
there is some pre-mixing of the combustion gases, this still is showing
signs of being a ("wispy") diffusion flame - not at all like the tighter
much bluer flame seen in Nathaniel's numerous YouTube videos and
mentioned in the instructions.

Experiment 1, Cooking
Cooking: Typical flame with a typical pot (and larger ones used for
some of the cooking). The tripod was in no way optimized (we raised
the stove about three inches with standard available mini-bricks; four
inches might have given higher efficiency - but more soot). It was
certainly easy to have too much heat for cooking pasta (boil-over once
when we weren't paying attention). At no time during the two hours of
operation did we (or could we) adjust anything. We are working on a
possible fix for that, when on a later weekend, we will try a means of
controlling the air flow. You should also next see a "convection skirt"
of the type being sold by Aprovecho.

Biochar Experiment 2 1/10/10

Using the same stove as yesterday, but this time with a cone in the center to displace the area that didn’t pyrolyze yesterday, we filled the stove with pellets again. This time however the stove had 15% less fuel because of the cone. We spent about a half hour trying to light the stove with twigs, vasoline, pine needles, paper, some other fluffy combustibles and fondue fuel. None of these things got the stove going. We ended up using the torch again. The torch lit the pellets in a minute or so and then it took about 15 minutes before we saw the good, steady, smokeless cooking flame. Once we got that good flame, we measured 2 hours 23 minutes of pyrolysis. The stove burned for the about the same amount of time as yesterday, but this time all the pellets were pyrolyzed. The outer can seemed to have the same temperature pattern today as yesterday.

Ignition: torch (shorter time than yesterday)
Pre-burn Fuel Weight: 49.5 oz wood pellets (same kind as yesterday)

Post-burn Fuel Weight (Char): 14 oz (28.2 % of starting weight, same as yesterday)

Post-burn volume: a little less than half

Calculated output to pot: 287 watts (This number is much lower than yesterday’s. We don’t like our thermometer for this application, so both days’ numbers are suspect.)

Time: 2 hours 23 (more carefully measured than yesterday)

Those temperatures were pretty consistent until the pyrolysis ended and we put a cap on the top. Unlike yesterday, we didn’t put the bottom in water. Smoke began to come out of the holes at the bottom and the temperature at the bottom began to rise. We suspected that some combustion was starting to take place. We poured the pellets into a tray but they seemed to be getting hotter rather than cooler so we scooped them into another canister and put on a tight lid so no more oxygen would be available.

Experiment 2, Cone

Cone - Showing the cone and the interior (the latter after almost
five hours of operation). No signs of any excess heat anywhere on the
outside can. Little on the inner can, but considerable tarring on the
inside and the top portion of the cone. Probably a lot of interesting
pyrolysis science in understanding why the cone looks like it does after
2+ hours of operation one time. Note the many interior small holes.
Note the single screw holding the two cans together (not shown in Nathaniel's drawings [at http://worldstove.com/wp-content/uploads/2009/11/EverythingNice_Stove_In...
] but mentioned at the bottom of p 3. We found all the instructions
complete, but guess we have to test a lot more fuel combinations before
we get the tight blue flame mentioned in the instructions.

Experiment 2, After Pyrolysis
Exp 2 (Sunday)
After Pyrolisis A view into the unit perhaps ten-fifteen minutes after the
unit stopped operating - and began smoking (pretty profusely, so you
want to react quickly). We placed a second lid to cover the opening -
but nothing else.(no covering of the lower holes - which we would likely
try to do next time). Note good uniformity of the char except right in
the middle where you can see the tip of the added cone. This is the first
time you can see that there are two cans - with the spacing of about a
centimeter (exact spacing dictated by can availability; this outer can is available at
about $.50-$1.00; no cost for the inner can). At the lower left is the
(pre-trimmed) pine cone which charred perfectly after being placed into
the unit.. No lighting up, no combustion, perfect retention of tiny
features - proving the lack of oxygen just below the flames seen in
other pictures. The unit was initially filled up to within 3/4 inch of
the top of the inner can, per Nathaniel's instructions, so you can see
there was perhaps 35-40% shrinkage.

Experiment 2, Char
Exp 2 Char: This to show the good uniformity of the resulting
char. Just a few that looked torrified (deep brown color - but we
can't even see them in this photo), not charred. In Experiment #1,
with no interior cone, perhaps 15% uncharred, roughly in the volume
taken up by the cone.

New plans and new ideas: We want a sliding band around the bottom of the can which can be used to regulate airflow through the holes and maybe the pyrolysis rate. When the band slides down, it will partially close the holes. When pyrolisis has finished, the band can be pushed all the way down to cover the holes entirely and keep oxygen out.

Part B. Technical Description

(by Al)

The inner tin was a Yuban Coffee can, with diameter 6.05 inches (excluding the roll bead where the bottom is attached. The original height of the can was 7.5 inches, and the height was trimmed down to 6.7 inches above the inside of the bottom surface. 74 holes .0.159 inch diameter were drilled on a line 0.75 inches from the bottom.

The outer tin was a decorative cookie tin with a fitted lid. The diameter of the can (excluding the rolled bead that attached the bottom) was 6.4 inches. A 3 inch diameter hole was cut in the center of the lid. The lid was 7.1 inches above the inside of the bottom of the can. 33 holes of 0.5 inch diameter were drilled as close as possible to the bottom of the outer can.

The inner can was filled to about ¾ inch of its top with pine pellets intended for use with pellet stoves. The weight of the fuel was 58.5 oz (1.66 kg). These pellets were ignited using a propane torch over the entire top surface for about 1 minute.

The stove operated with what appeared to be constant output for 140 minutes. A water heating test was performed with a pot set about 3 inches above the stove opening. Two liters of water was placed in a covered pot of diameter 8.5 inches and height (without lid) of 3 inches. Water temperature was measured using a “point-and-shoot” infrared thermometer. (I suspect that at higher temperatures this thermometer reads low, as it most likely senses the temperature of the steam above the water in the pot, and not the water itself.) Water start temperature was 12.5C, and finish temperature was 81.1C, at which time boiling bubbles were coming off the bottom of the pot, and much energy was being lost to steam. Elapsed time was 17 minutes.

When the flame extinguished, much smoke came from the stove, so a lid without a hole was placed on top of the stove. Smoke continued to pour from the holes at the bottom of the stove, so it was placed in a pan of water to cover the holes. This resulted in wetting of the contents of the stove. After cooling, the stove was opened and the contents examined. The fuel was found to have been converted to char, except for a portion of pellets about 1.5 inches high and 3 inches in diameter at the bottom of the stove.

Since the fuel was wet, it was not weighed. Instead, the wet fuel including the unconverted pellets was placed in a container and heated to complete pyrolization. The weight of the remaining char was 16.5 oz (28.2% original weight).

A hollow metal cone of height 4.5 inches and diameter 4.5 inches was made, and placed in the bottom of the inner can before adding fuel pellets for a second run. This time the weight of the fuel was 49.5 oz, the burn time was again 140 minutes, and the weight of the remaining char was 14 oz (28.3% original weight). This time all but 1 or 2 pellets appeared to have been converted to char.

Laurens Rademakers, Biochar Fund
December, 2009

See the attachment for full sized pictures.

we've designed a new biomass stove that produces char. The stove is a simple hybrid of a rocket stove and a retort. We would be glad if you could upload it to the stoves list, because we want to see what the community thinks of it. It is only a concept, even though we've tested some basic design steps.

We will be testing this design at our large biochar site in Congo, where our project soon kicks off.