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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 Cambodia
http://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.

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Review - Cooking with rice husk-ETHOS 2011

  • 1. Cooking with Rice Hulls: A Primer on Current Technology, Projects, and Challenges Marc Pare, 2011
  • 3. Rice Hull as Fuel Low energy density High ash content (20% volume left over) <5% for wood Small particle size
  • 5. Lò Trấu: Breakdown ● Available since at least the 1950s ● Common around Vietnam ● Features: ● Hands off operation ● Continuous ● Inexpensive
  • 6.
  • 7.
  • 8.
  • 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
  • 11.
  • 12.
  • 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
  • 19.
  • 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.