Rice Husks

Alexis Belonio, Bima Tahar, and Bonny Minang

A super low-cost, blue-flame rice husk gas stove was recently developed in Indonesia to provide households with an affordable clean-burning cooking device using rice husks as fuel.

Within the 3 years of development on rice husk gasifier stove, PT Minang Jordanindo Approtech has finally come up with the super low-cost, blue-flame rice husk gas stove carrying a selling price of US$10 to 15, which is very much cheaper as compared with the previous model with a selling price of US$20. With this development, consumers don’t need to amortize for the stove, as what is currently practiced in villages in Indonesia, for them to acquire a unit of the stove in order for them to save money on fuel. Moreover, this stove is now made available to end users at a low cost, freeing the distributors from the task of devising financing schemes just to make the technology affordable to the local households.

As shown, the stove consists of only few parts. It was designed and made so simple to maximize the use of materials and to simplify the production using locally available resources. This stove model has the following basic parts: (a) the casing is made of tin can and can be bought at a very low price from a Can Factory; (b) the reactor can be subcontracted from a sheet metal manufacturer as well as the stove cover
and the burner; (c) the fan, which uses DC 12 volt, 2 watt supplies the required air to gasify rice husks. The flame coming out of the burner is bluish in color, which indicates a very clean gas. It has low black carbon emission of about 50 ug/m3 and below. The CO2 emission is about 0.6 kg CO2 per kg rice husks.

Alexis T. Belonio, Daniel A. H. Belonio, and Lucio Larano, August 2010

This paper (see attached) describes a continuous-flow rice husk gasifier (CFRHG) designed and developed for various thermal applications such as cooking, drying, kiln firing, baking, and others. The technology follows the principle of a moving-bed, down-draft reactor converting raw rice husks into combustible gases that is rich in carbon monoxide (CO) and hydrogen (H2).

Different sizes were built and tested in collaboration with the private sector both in the Philippines and in abroad. The gasifier units which were built, tested and evaluated have varying reactor diameter, ranging from 0.40 to 1.20 m with a corresponding power output of 35.7 to 321.2 kWt. The rice husk consumption rate for the different reactor diameters tested ranges from 19 to 169 kg per hour. The specific gasification rate of the gasifiers was found to operate well at 150 kg/hr-m2. The temperature of the gas leaving the reactor varies from 150° to 270°C for all the units tested. The flame temperature reaches as high as 400° to 800°C, depending on the size of the reactor. The bigger the size of the reactor diameter, the higher is the flame temperature. The parasite load varies from 4.2% for the smaller diameter reactor to 1.5% for the bigger model. Combustible gases are generated within 5 to 30 minutes for the different sizes tested. The heating value of the gas ranges from 1200 to 1400 kcal/m3. And, only one person is needed to operate the small gasifier and two persons are needed for the big gasifier model.

Results of the tests showed that the CFRHG is convenient to use and its operation is easily controlled with the use of gas valves. There is no smoke emitted during operation. Black carbon content and tar emissions were found to be very minimal. The char produced can be used for agricultural application and the ash produced can be used for the production of low-cost construction materials.

Rice-powered stove ignites new hope for poor farmers

Alexis BelonioAlexis Belonio

Continuous-Flow Rice Husk Gasifier for Small-Scale Thermal Applications
Alexis T. Belonio, Appropriate Technology Center, Central Philippines University, Iloilo City, Philippines, November 11, 2006

Super Turbo Rice Husk Quasi Gasifier Stove
Alexis T. Belonio, Appropriate Technology Center (APPROTECH), Central Philippine University, Ioilo City, Philippines October 30, 2006

Select images to enlage.

Summary of Aprovecho’s Summer Stove Camp, 2006
By Dean Still and Nordica MacCarty, September 6, 2006

Aprovecho Camp 2006 02Aprovecho Camp 2006 02

Stove Camp 2006 was extremely interesting, especially because we had experts here who could help define what is known, figure out what needed to be done to expand the state of knowledge, and then, most importantly, have the tools to accomplish the experiments.

For Dean, the best moments happened around the table above when Chris Roden, Jonathan Lewis, the Aprovecho staff and everyone tried to get a general feeling for wood-burning stoves effect on global warming. Aprovecho’s recent tests at CSU of greenhouse gas emissions such as CO2, Methane, N2O, NOx, etc. helped to predict the gaseous emissions from the following stoves:
• Three stone fire
• Rocket stove
• Karve Gasifier stove
• Philips fan stove
• Charcoal Jiko stove
• Mayon rice hull burning stove

The gases, however, are only a part of the picture: particles also play an important role in the atmosphere. We learned that elemental (black) carbon particles produced in flames have a warming effect 1000 times greater than CO2 per gram, while organic carbon (white) particles produced by smoldering have a cooling effect 150-200 times stronger than CO2. Thankfully, Chris Roden had brought his and Dr. Tami Bond’s ARACHNE system which could measure the composition of the total PM to determine what percentage of black or white particles were produced by the stoves above. Chris, Damon and Nordica were at the lab till 11pm having a great time testing these stoves. Results should be available soon.

Doing this kind of research in a small lab in Creswell, Oregon for no money is what ETHOS stove camp is all about!

The publicized theme of this year’s camp was a competition to design the cleanest-burning fan stove. Two categories, side feed and top feed were awarded prizes. The top feed prize went to Dr. Paul van der Sluis for the Philips fan stove. The side feed Rocket stove with fan developed by Roger and Sule of Colorado State was the cleanest burning side feed stove. Congratulations to the winners!

Single Burner Rice Husk Gas Stove

Institutional Size Rice Husk Gas Stove, Alexis T. Belonio, Central Philipine University, Philipines. December 2005

Aprovecho research Center, July 18, 2005

Download the full report Stove Performance Report: Mayon Rice Hull Stove

Alexis Belonio and Djoewito Atmowidjojo, Central Philippines University and Approtech Indonesia, August 30, 2007


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