CO/CO2 Ratio in the Charcoal Stoves Tested at Aprovecho

CO/CO2 Ratio in the Charcoal Stoves Tested at Aprovecho (pdf)
Dean Still, Aprovecho Research Center, June 23, 2006

The following graph plots the levels of CO and CO2 during one test each of the charcoal burning rocket stove and Jiko-type charcoal stove from Ghana. A higher level of CO2 suggests a higher burn rate of fuel.

It can be seen that even though the CO level for the rocket drops below 10 ppm, the CO2 level remains high suggesting a high firepower continues. The Ghana charcoal stove has a lower level of CO2 with a considerably higher level of CO.

The following graph plots the ratio of CO to CO2 for each stove, showing how cleanly the stove is burning the fuel. A lower CO/CO2 ratio indicates a cleaner-burning stove.

CO/CO2 Ratio for Charcoal and Ghana Stove

Higher ratios mean the stove was making more CO and less CO2. Perfectly efficient combustion would produce all CO2 and no CO because the CO is combusted and changed into CO2.

The CO/CO2 ratio has been suggested as another method for determining how cleanly a stove is burning. It may be possible to use the CO/CO2 ratio as a benchmark for stove combustion efficiency. The South African Bureau of Standards suggests that the CO/CO2 ratio from paraffin (kerosene) stoves should be 2% or less. The blue line drawn across the graph above shows this level. Over the duration of the test, the charcoal rocket does not meet the standard but it is interesting that the ratio dropped below 2% after the stove reached 725 degrees C.

See Also:

Comparing the Charcoal Burning Rocket and Jiko Stoves Aprovecho, June 22, 2006

Video: Charcoal Burning Rocket Stove Reduces CO Emissions Aprovecho, June 21, 2006

CO Emissions From a Charcoal Rocket Stove Aprovecho, June 12, 2006

Initial lmprovement of a Charcoal Burning Rocket Stove Aprovecho, June 5, 2006

See Discussion on Improving Charcoal Stoves in List Archives May-June 2006
Peter Verhaart and Crispin Pemberton-Pigott on Improving Charcoal Stoves, June 1, 2006

Previous Discussions and Studies:
CO/CO2 Ratio Tami Bond, University of Illinois at Urbana-Champaign, August 21, 2005

CO a % of CO2? Frans Peeters, May 25, 2005

Charcoal Stove Amit Suri, April 5, 2005

Testing with a CO + CO2 Meter Crispin Pemberton-Pigott, New Dawn Engineering June 30, 2004

Charcoal Burning to CO2 Tom Reed, Biomass Energy foundation, May 23, 2004

Review of Emissions Testing Hood at Aprovecho" Dale Andreatta, January 28, 2004 (ETHOS 2004)

Cook Stove Efficiency, Health and Environmental Impacts, Biomass Lab Report, Yanxia Chen, David Pew, Dan Abbott 2002

Small Scale Biomass Systems Dan Kammen, RAEL, 2002

Research, Development and Commercialization of the Kenya Ceramic Jiko and other Improved Biomass Stoves in Africa Dan Kammen, RAEL

Emissions target for wood fuelled cooking Stove" Tom Reed and Alex English, August 28, 1998

Emission Measurements Etienne Moermann, July 17, 1997

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