Mr. Anderson worked on his designs with Tom Reed, a former Massachusetts Institute of Technology chemist. Mr. Reed invented the top-lit updraft (T-LUD) biomass stove, one of a class of stoves that can “gasify” its fuel. In gasifier stoves, biomass burns until only charcoal and burnable gases remain; the gases are separated and ignited, producing a smokeless blue flame like that of a natural gas stove, leaving only charcoal behind.
In traditional wood fires, these two processes happen together, creating the familiar yellow, smoky flames. Separating the stages makes for a cleaner, more controlled burn that has made the technology popular worldwide.
Reed and Anderson burned wood in their T-LUD stoves, but neither succeeded in gasifying finer agricultural waste. Then, after seeing a Reed T-LUD stove demonstration at a conference in Thailand, Belonio started imagining a husk gasifier.
“Nobody told Alexis Belonio you weren’t supposed to do this with rice husks,” says Anderson. “So he just went off and did it.”
The secret to Belonio’s success is good engineering and adequate air, Anderson explains. His design includes a small electric or battery-powered fan that circulates air through the husks, enabling them to burn more efficiently.
The fan and fuel sit in the bottom of an iron and steel tube more than a yard long. The tube traps the gases the husks release when they’re lit – mostly hydrogen, methane, and carbon monoxide – and combusts them at the burner on top of the tube. Users can raise or lower the flame by changing the fan speed. When the husks have burned, the remaining charcoal can serve as a fertilizer for crops.
“This technology is superior to virtually everything else out there,” says Anderson. “Belonio stimulated me and others to go back and look again at rice husks and other fine materials.”