Abundance of rice hulls stirs imagination

New Survey on Rice-Hull Stoves in the Philippines.

By Jose S. Nicolas, Rural Enterprise Development Foundation Inc., Philippines

2 - 3 million tons of rice hull materials are generated in the Philippines annually. Of this total tonnage, a very conservative estimate is that only 5 % are utilized as fuel, feeds, etc. The remaining balance (95%) is either dumped or burned indiscriminately with no regard for environmental degradation.

The rice hulls, however, as a renewable source of raw materials can be used for various purposes in agriculture, households, and industries. One major application of rice hulls is to use it as fuel substitute for firewood and LPG/kerosene gas.

Recently, we made a survey of rice hull stove users in five regions of the country. We recorded that a family of 6, in average, uses 3.4 tons of rice hull per year and has 10% to 15% fuel cost savings. For service industries like restaurants and food-processing plants, rice hull fuel consumption ranged from 16 to 365 tons per year.

The abundance of rice hulls in the countryside stirred the imagination of some entrepreneurial individuals to invent gadgets which would utilize rice hulls as a productive biofuel. For in stance, in the Pangasinan province, a very unusual stove was made out of indigenous materials, primarily of clay soil soaked in water and mixed thoroughly with rice hulls to produce an aggregate and later molded in an empty can. This stove, designed specially for the low-income group, can be purchased at USD 8 per unit (1995 price).

While the firewood is slowly disappearing from the hills and costs of fossil fuels getting stiffer, the rice hull can be obtained freely from village rice mills. This resulted in the widespread adoption of the rice-hull stove in the service industries as well as households.

The two most common types of rice-hull stove are: fixed and movable. Both models have a funnel serving as both storage and passageway for rice hulls. The movable type is a four-legged table stove with 2 pot holes. It is a very popular cooking gadget in the household kitchen (Figure 1.)

The fixed type models are heavy-duty stoves used in restaurants and food processing plants. The 34 pot holes model most used in restaurants (Figure 2.) can store as much as 20 sacks (15 kg/sack) of rice hulls at a time. The price of these stoves ranges from USD 800 to USD 1,000 per unit (1995 price).

Whereas food processing plants often uses a simpler 1 pot hole version due to its economy and efficiency.

The idea stirs the imagination of the research institutes as well. The Philippine-based International Rice Research Institute (IRRI) developed a single-pothole rice-hull stove called "IRRI-IPA QALAN" (Figure 3.), and the Philippines Rice Research Institute developed a stove prototype known as a "Maligaya Rice Hull Stove''.

More information:
Jose S. Nicolas, Rural Enterprise Development Foundation Inc.,
9480 Lopez Avenue, Los Banos Laguna, 4030, the Philippines.
Fax: +63-94-5360016
c/o Bessie Burgos (PCARRD) or +63-2817-8470 and +632891-1292 c/o Dea Bonilla/IRRI.