POLTTOPROSESSIEN LASKENNALLINEN JA KOKEELLINEN TUTKIMUS:

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1 1 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

2 2 High Temperature Air Combustion From: IFRF Online Combustion Handbook.

3 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

4 4 Flameless combustion r D 2 g 2 D Da = g = gas phase mass diffusivity r = droplet radius d law s / reaction time Da increase burning rate increases until critical ignition point. Droplet size decreases Da decreases. When gas phase transport time ~ chemical reaction time extinction. From: HiTACG 2005, Essen, Joachim A. Wûnning Infinitely fast chemistry d 2 law.

5 5 Why HTAC? Energy saving Thermal energy from exhaust gases used to heat up combustion air. Higher heat flux from flames. CO 2 reduction Fuel consumption decreases CO 2 emissions decreases. NO x 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

6 6 Example process GAS RECIRCULATION AIR FUEL EXHAUST GAS HTAC FLAME HEAT RECIRCULATION Recirculation of flue gases the most common dilution mechanism.

7 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.

8 8 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.

9 9 Test reactor Uniform droplets of size µm. Temperature 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.

10 10 Applications ppm NO N 2 O CO CO 2 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).

11 11 Situation Droplet generator design has been chosen. Test reactor design almost clear. Data mining

12 12 Thank you. Questions?

13 13 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: industrie/ippc_konferenz/delacroix.pdf IFRF Online Combustion Handbook. Available at: