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POLTTOPROSESSIEN LASKENNALLINEN JA
KOKEELLINEN TUTKIMUS:
Application of HTAC Technique in Combustion of Liquid Fuels
Janne Wahlman and Antti Oksanen
Energy and Process Engineering
Tampere University of Technology
Matti Kytö
OILON Energy
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
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High Temperature Air Combustion
From: IFRF Online Combustion Handbook.
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
3
Flameless mode
•
•
Reactants must exceed self-ignition
temperature.
Reactants must be diluted before
combustion. (=inertisation, reduces
local temperatures)
From:
“THE FLAMELESS OXIDATION MODE”: AN EFFICIENT COMBUSTION DEVICE LEADING
ALSO TO VERY LOW NOX EMISSION LEVELS
Franck Delacroix
IFRF Online Combustion Handbook
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
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Flameless combustion
d −law
2
Da =
rs2 / Dg
reaction time
Dg = gas phase mass diffusivity
r = droplet radius
• Da increase → burning rate
increases until critical ignition
point.
• Droplet size decreases → Da
decreases.
• When gas phase transport
time ~ chemical reaction time
→ extinction.
• Infinitely fast chemistry d2 –
law.
From: HiTACG 2005, Essen, Joachim A. Wûnning
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
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Why HTAC?
Energy saving
• Thermal energy from exhaust gases used to heat up combustion air.
• Higher heat flux from flames.
CO2 reduction
• Fuel consumption decreases → CO2 emissions decreases.
NOx reduction
• Small temperature gradients and under oxidizing conditions.
Equipment size reduction
• Uniform heat flux distribution and thermal field uniformity.
• Volume of the combustion chamber is fully used.
Lower
• noise levels (no flame front)
• thermal stress to structures
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
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Example process
GAS RECIRCULATION
AIR
EXHAUST GAS
FUEL
HTAC FLAME
HEAT RECIRCULATION
•
Recirculation of flue gases the most common dilution mechanism.
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
7
Fuels
Previous research
• gaseous (Japan)
• solid and LFO (Germany, Italy, Poland, Sweden and France).
→ HFO, bio oils, fat, and liquified wastes are still left to be studied. This is
because
•
•
•
there have been no emission regulations for these fuels and the research is
very challenging.
Furthermore, the price of high quality fuels is rising.
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
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Project goals
KINETIC PARAMETERS
•
Developing a test reactor for detailed reaction kinetics study.
•
Detailed model for combustion of a liquid particle using HTAC tehcnique (especially
oxidation of cenosphere ~75 % of combustion time).
•
Optimize air staging in burner / combustion chamber, which is the most important
factor in HTAC combustion.
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
9
Test reactor
Energy and process engineering department
•
Uniform droplets of size 100 – 200 µm.
•
Temperature 800 – 1000 °C.
•
Gas composition can be changed.
•
Possibility to use optical measurement
techniques e.g. LIF (TKK).
•
Cenosphere formation and oxidation
are done separately. (No collect-andreburn).
•
FTIR measurements of pyrolysis and
combustion gases.
Applications of HTAC combustion on liquid fuels
2.2.2007
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Applications
ppm
NO
N2O
CO
CO2
Test reactor for measuring reaction kinetics of almost any kind of liquid fuel.
→ Better modelling of flue gas emissions.
→ Easier and faster to begin measurements with a working installation.
→ Validation of CFD results for low quality liquid fuels.
Possibility to use HTAC technique for low emission gasification and combustion of
low quality liquid fuels (HTAG=high temperature air gasification).
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
11
Situation
• Droplet generator design has been chosen.
• Test reactor design almost clear.
• Data mining…
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
12
Thank you.
Questions?
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007
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References
Tsuji, H., Gupta, A.K., Hasegawa, T., Katsuki, M., Kishimoto, K., Morita, M.
High temperature air combustion: From energy conservation to pollution
reduction. Boca Raton 2003, CRC Press Ltd. 424 p.
Delacroix, F. The Flameless Oxidation Mode: An Efficient Combustion
Device Leading Also To Very Low Nox Emission Levels. ADEME. Available
at: http://www.umweltbundesamt.at/fileadmin/site/umweltthemen/
industrie/IPPC_Konferenz/Delacroix.pdf
IFRF Online Combustion Handbook. Available at:
http://www.handbook.ifrf.net/handbook/
Energy and process engineering department
Applications of HTAC combustion on liquid fuels
2.2.2007