Paul Olivier, September, 2011

Paul Olivier is working from Vietnam, and had put together a comprehensive pdf article explaining the benefits of using TLUD and other gasifier stoves to avoid cooking smoke and create biochar. Cooking Smoke is a major health problem in both rural and urban areas in Vietnam and many other parts of the world, and improved stoves that can also produce biochar can also help urban and rural people retain nutrients in their soils, and reduce pollution.

For more, please download the pdf: Biomass Gasification and the benefits of Biochar

D. Ariho, P. Tumutegyereize and K. Bechtel, Uganda December 2010

The Project was concerned with the evaluation of the energy efficiencies of commonly available biomass
fuels in Uganda in a “Champion-2008” Top Lit Updraft (TLUD) gasifier stove. Selected biomass fuels included; Eucalyptus wood from plantations, maize cobs (agro-waste), papyrus, spear grass, noncarbonized briquettes (agro-waste and sawdust) and off-grade jatropha seeds. Moisture content
measurement of biomass fuels was determined using oven-dry method. The energy efficiencies of the
biomass fuels in the “Champion-2008” TLUD gasifier stove lied between 12 and 19%. Maize cobs had the highest energy efficiency of 18.40% and spear grass had the lowest of 12.64%. Maize cobs and papyrus were not significantly different from Eucalyptus wood. Non-carbonized briquettes and off-grade jatropha seeds had a higher operation time compared to the rest of the selected biomass fuels though faced with a problem of higher starting time but able to perform when started. The results obtained indicate that a variety of biomass fuels in Uganda can perform well in the “Champion-2008” TLUD gasifier stove, thus the need for adoption to combat deforestation problem.

See the attached report FUELS IN A TLUD GASIFIER STOVE.pdf (in pdf) for more detail.

Paul Olivier, April 2010

Today we put in operation for the first time the 250 gasifier with a stove top.
This gasifier has a single 2-inch pipe that vents housing air to a warmer grate.
This pipe had no butterfly valve or other restriction.
We used the same small 80x80 mm fan as in the 150 gasifier.
This fan had no problem at all supplying air to the reactor and to the 2-inch pipe.
The burn lasted almost an hour on rice hulls, even though the height of the reactor was no more than 70 cm, the same height as in the case of the 150 stove.
The warmer grate had sufficient heat from the housing to fry an egg, as indicated in picture 855.
We obtained a bright blue flame, as shown in picture 865,
although the camera did not have the right lighting to display it properly.
The stove top was not properly reinforced when a large pot filled with water was placed on top.
There was a deflection of a few mm's.
However this can be easily remedied with two more lateral braces underneath the stove top.
In conclusion, the 250 gasifier works well and delivers an enormous amount of heat.

H. S. Mukunda*, S. Dasappa, P. J. Paul, N. K. S. Rajan, Mahesh Yagnaraman, D. Ravi Kumar and
Mukund Deogaonkar, March 2010

Published in Current Science Online

The direct link is here: (it’s about 1/2 Mb)


Development of a new class of single pan high efficiency, low emission stoves, named gasifier
stoves, that promise constant power that can be controlled using any solid biomass fuel in the form
of pellets is reported here. These stoves use battery-run fan-based air supply for gasification (primary air) and for combustion (secondary air). Design with the correct secondary air flow ensures near-stoichiometric combustion that allows attainment of peak combustion temperatures with accompanying high water boiling efficiencies (up to 50% for vessels of practical relevance) and very low emissions (of carbon monoxide, particulate matter and oxides of nitrogen). The use of high density agro-residue based pellets or coconut shell pieces ensures operational duration of about an hour or more at power levels of 3 kWth (~12 g/min). The principles involved and the optimization aspects of the design are outlined. The dependence of efficiency and emissions on the design parameters are described. The field imperatives that drive the choice of the rechargeable battery source and the fan are brought out. The implications of developments of Oorja-Plus and Oorja-Super stoves to the domestic cooking scenario of India are briefly discussed.

The process development, testing and internal qualification tasks were undertaken by Indian
Institute of Science. Product development and the fuel pellet production were dealt with by First
Energy Private Ltd. Close interaction at several times during this period has helped progress the
project from the laboratory to large scale commercial operation. At this time, over four hundred
thousand stoves and 30 kilotonnes fuel have been sold in four states in India.

Qpre, India March, 2010

More information on their web site :

Design and Development of a Natural Draft Biomass Gasifier
R. Krishna Kumar February 28, 2009

Naturl Draft Gasifier - KumarNatural Draft Gasifier - Kumar


  • Operates under the principlle of “ Chimney Effectt ”
  • Natural draft caused by density difference


  • No blower is required for the operation
  • Automatically takes the required quantity of air for Gasification
  • Convey the Producer Gas formed by Gasification - Naturally
  • Reduced fuel consumption compared to traditional chulas

More detail, schematic pictures and testing information are in the attached pdfs and in the 2004 discussion:

Paal Wendelbo and His “Peko Pe” Top-Lit UpDraft (TLUD) Gasifier Cookstoves
Paul Anderson, January 19, 2009

Paal WendlboPaal Wendlbo

This report is in three parts: pioneer experiences; selection of photographs; and technical specifications of the PP stove. The report is based on e-mail interviews and materials provided by Paal Wendelbo in July 2008 and December to Paul S. Anderson, who has added interpretive content. Mr. Wendelbo has approved the basic content about himself, but Dr. Anderson is responsible for any errors, omissions, and editing.


Anila Biomass Gasifier Stove Designed and built by Professor U.N. Ravikumar (Eng) Mysore University, India In Biochar and SCAD presented by David Friese-Greene, The Schumacher Institute, Bristol (9.88MB pdf)

Anila Stove Anila Stove
Combustion Cycle Combustion Cycle
Cutaway Diagram of the Anila Stove Cutaway Diagram of the Anila Stove

Peko Pe 3 Liter Test Stove and Fuels
Paal Wendelbo, August 20, 2008
Boiling TestBoiling Test
The Multifuel Combustion System (MFCS) is a flexible system designed for bioenergy household and institutional cooking. It is based on one energy unit (the Peko Pe) which single or multiple will cower all needs of energy for inside and outside cooking. The energy unit has to be seen as a “battery” loaded with energy, and when empty, replaced with a new loaded until the food is ready. Two units of 3 litres will cover the needs of a family, ½ full with fuel for coffee or tea, a bit more for porridge and 1 ½ for the whole meal. For boiling beans, empty the unit and place the pot on the glowing char. A simple handle to hold the pot for mingling the enchima will be a good help. (See the drawing). For institutional cooking more 10litre units will be the best 3 Units will boil 60 litres within 50 minutes and continue boiling 2 more hours on 6kg of chopped wood-sticks. The system can be used for heating air or water, frying, cooking and baking bread, even smoking fish.

The MFCS will be faced the same problems as other type of new stoves and has to be trained, it is boiling faster and saving fuel (saving 2/3), burning with no smoke and little soot (depending a bit on type of fuel)
The system has been working for about 15 years and plans or more information is available by

Attached you will find some pictures of a simple 3litre teststove I use to test types of biofuel.
1. chopped woodstick from energy forestry.
2. chipped wood from sawmillslabs.
3.wood pellets.

3 Types of Fuels3 Types of Fuels

All types brought 3 litre of water from 17C to 100C within 13-15 minutes. No smoke no soot. Between 600C and 700C flame temperature.
Flame 1Flame 1
Flame 2Flame 2


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