3rd Africa Rice Congress Theme 3: Rice processing and marketing Mini symposium: improving rice processing technologies in Africa Author: Yank

1. Development of an Improved
Stove for Small Scale Parboiling
Audrey Yank
Michael Ngadi
Robert Kok
McGill University, Québec, Canada

2. Introduction - Energy
• Rice parboiling is an energy
intensive process
• 80% of the energy in
developing countries comes
from biomass (UNEP, 2001)
• Low stove efficiency leads
to high fuel demand and
wood use

3. Introduction - Health
• Smoke exposure affects the
respiratory health
• 1.6 million people, mainly women
and children, die every year as a
result of the wood smoke (WHO, 2006)
Source: practicalaction.org/smoke-andits-impact

4. Objectives
Develop and test improved stoves for small
scale rice parboiling:
 Reduce emission of air pollutant
 Increase thermal efficiency and reduce wood
requirements
 Increase user safety during rice parboiling

5. 3-Stone Stove
Stove 1
Stove 2 (with grate)
Stove 3 (with chimney)

6. Water Boiling Test - Protocol
High Power: Cold Start
High Power: Warm Start
Low Power: Simmering

7. Preliminary Results
Table 1: Time to boil* 15L of water (min)
Stove Type
3-Stone Stove
Stove 1
Stove 2
(with grate)
Stove 3
Cold Start
42
28
Hot Start
51
23
33
31
26
30
* Starting with 15◦C water temperature up to 98.7 ◦C

8. Thermal Efficiency (%)
30
25
20
15
10
5
0
3-Stones
Cold Start
Stove 1
Stove 2
Hot Start
Stove 3
Simmering

10. Gas Emissions – Concentration (ppm)
Improved Stove
40
30
20
10
0
40
Hydrocarbons
Carbon Monoxide
3-Stone Stove
30
20
10
0
0
5
10
15
20
25
Time (min)
30
35
40

11. Conclusion
• Improved wood stoves have the potential to
significantly reduce the wood requirement for
rice parboiling.
• The design of the wood stoves still needs to
be optimized to reduce the emissions.

12. Questions?
Thank You!
Merci!