Cooking with Rice Hulls: A Primer on Current Technology,

Projects, and Challenges

Marc Pare, 2011

What about usability?

Rice Hull as Fuel

Low energy density

High ash content (20% volume left over)<5% for wood

Small particle size

Lò Trấu(direct combustion)

Belonio Gasifier(gasification)

Lò Trấu: Breakdown● Available since at least the 1950s ● Common around Vietnam● Features:

● Hands off operation● Continuous● Inexpensive

Drawbacks● Still smokey, even with chimney (unless you

tend constantly)● Start up is slow● Pot size choices limited

Portable Variation● Mayon Turbo, Quasi-gasifier, …● Same principle of direct combustion

Requires constant, skilled tending

Belonio Gasifier

Belonio Gasifier: Breakdown● By Dr. Alexis Belonio in the Phillipines● TLUD with Fan● Blue flame (sexy)● Emissions like a gas stove● Great thermal performance● Lights up almost instantly● Nice turn-down with fan● Wonderful handbook. “Rice husk gas stove

handbook”

Brother Kent Good in Cambodiahttp://web.mac.com/kentcgood/

Belonio Gasifier: Drawbacks

● Loading and unloading is inconvenient● Wind puts flame out easily● Disastrous failure mode if left on

● RESULT: 10% adoption rate (Vietnam National University, 200 stove study)

Remote Burner● One possible solution: downdraft operation,

burn gas in separate burner● Allows continuous operation

Remote Burner● BUT

● Lighting now not as easy● Persnickety burners● Tar collection in pipes

(cooking gasifiers are run largely in the pyrolysis mode, not gasification. 90 SGR* vs. 140 SGR for gasification)

*SGR: Specific Gasification Rate [kg / hr-m^2]

Rice husk cook stoves: Many designs are technically possible, but no product exists that balances technical feasibility with user needs at a large scale.