Slides from 2012 ETHOS presentation. Content based on a year of field work in Vietnam. Reviews basic capabilities and limitations of existing technologies to convert rice hull into cooking energy.

1. Cooking with Rice Hulls: A
Primer on Current Technology,
Projects, and Challenges
Marc Pare, 2011

2. What about usability?

3. Rice Hull as Fuel
Low energy density
High ash content (20% volume left over)
<5% for wood
Small particle size

4. Lò Trấu
(direct combustion)
Belonio
Gasifier
(gasification)

5. Lò Trấu: Breakdown
● Available since at least the 1950s
● Common around Vietnam
● Features:
● Hands off operation
● Continuous
● Inexpensive

9. Drawbacks
● Still smokey, even with chimney (unless you
tend constantly)
● Start up is slow
● Pot size choices limited

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

13. Requires constant, skilled tending

14. Belonio Gasifier

15. 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”

16. Brother Kent Good in Cambodia
http://web.mac.com/kentcgood/

17. 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)

18. Remote Burner
● One possible solution: downdraft operation,
burn gas in separate burner
● Allows continuous operation

20. 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]

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