Rice Husk Gasifier
More than 5 million tons of rice husk are produced annually in sub-Saharan Africa (SSA). They are either dumped and/or burnt, polluting the atmosphere. The use of rice husk as fuel for cooking and local artisanal food processing industry can be a suitable alternative to fuelwood and contribute towards reducing deforestation in SSA.
AfricaRice has adapted the household gasifier stoves from Southeast Asia by increasing their size, changing their air-supply system and coupling to the GEM to develop the ‘Mini-GEM’ parboiler, which was pilot-tested in Benin and Côte d’Ivoire. Despite being a vast improvement on traditional methods of parboiling, the fuelwood energy supply of the GEM presents problems.
First is the rising cost of fuelwood as the forests and countryside become denuded of dry wood. Second is the production of smoke and soot – blackened pots take up valuable labor for cleaning. One answer to these is a by-product of rice milling: husk. Rice husk can be burned in fan-assisted gasifier stoves to generate heat.
AfricaRice improved the GEM parboiling processing equipment to work with unprocessed rice husk as a fuel. This is saving time and money, producing less pollution (smoke and soot) and
generating a ‘free’ fertilizer (biochar) into the bargain.
In the pilot tests, women parboilers simply collected the husk from the miller along with their milled rice, effectively replacing increasingly costly wood with free fuel. At one site in Côte d’Ivoire, the innovation platform parboilers saved almost US$ 4000 in wood costs over a 14-month period while parboiling 136 t of paddy. The husk also produces near-zero smoke and soot, thereby alleviating air-pollution and pot-blackening.
An additional environmental bonus is that heat production from rice husk can produce biochar, an effective fertilizer. Women parboilers were trained to prevent the burning husk from turning to ash and rather generate biochar as a by-product.
The rice husk gasifier used in the mini GEM parboiling system can be easily built by local artisans and are cheaper to operate especially near rice mills.
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