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PARALLEL AND SERIES-REACTION MECHANISMS OF WOOD AND CHAR COMBUSTION

ABSTRACT
Thermo gravimetric curves in air of beech wood and char, obtained from conventional pyrolysis of beech wood at a laboratory scale, have been re-examined using different kinetic models. Multi-step reaction mechanisms consisting of either four (wood) or two (char) reactions are needed for accurate predictions of weight loss curves. In the case of wood, three reactions are linear in the reactant mass fraction whereas the fourth step presents a power-law dependence. A linear reaction for devolatilization and a non-linear reaction for combustion are used for the weight loss curves of char. It has been found that activation energies and pre-exponential factors are in variant with series or parallel reactions, providing changes in the stoichiometric coefficients. Further more, the activation energies of the two reactions occurring at higher temperatures in the four-step mechanism (wood) and those of the two-step mechanism (char) are the same. Thus pre-exponential factors and reaction order take into account variations in the char reactivity derived from different pyrolysis conditions.
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PAPER SUBMITTED: 2004-03-23
PAPER REVISED: 2004-04-25
PAPER ACCEPTED: 2004-04-27
DOI REFERENCE: https://doi.org/10.2298/TSCI0402051B
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THERMAL SCIENCE YEAR 2004, VOLUME 8, ISSUE Issue 2, PAGES [51 - 63]
REFERENCES
  1. Kanury, A. M., Combustion characteristics of biomass fuels, Combustion Sciences and Technology, 97 (1994), 469-491.
  2. Smith, I. W., he combustion rates of coal chars: a review, Proceedings, Nineteenth International Symposium on Combustion; The Combustion Institute, Pittsburg, 1045-1065, 1982.
  3. Ruth, L. A., Energy from municipal solid waste: a comparison with coal combustion technology, Progress in Energy and Combustion Science, 24 (1998), 545-564.
  4. Bilbao R., Mastral J. F., Aldea M. E., Ceamanos J., The influence of the percentage of oxygen in the atmosphere on the thermal decomposition of lignocellulosic materials, Journal of Analytical and Applied Pyrolysis, 42 (1997), 189-202.
  5. Di Blasi C., Branca C., Global degradation kinetics of wood and agricultural residues in air, The Canadian Journal of Chemistry Engineering, 77 (1999), 555-561.
  6. Branca, C., Di Blasi, C., Global intrinsic kinetics of wood oxidation, Fuel, 83 (2004), 81-87.
  7. Laurendeau, N. M., Heterogeneous Kinetics of coal char gasification and combustion, Progress in Energy and Combustion Science, 4 (1978), 221-270.
  8. Janse, A. M. C., de Jonge, H. G., Prins, W., van Swaaij, W. P. M., The combustion kinetics of char obtained by flash pyrolysis of pine wood, Industrial and Engineering Chemistry Research, 37 (1998), 3909-3918.
  9. Di Blasi, C., Buonanno, F., Branca, C., Reactivities of some biomass chars in air, Carbon, 37 (1999), 1227-1238.
  10. Varhegyi, G., Szabo, P., Antal, M. J., Kinetics of charcoal devolatilization, Energy & Fuels, 16 (2002), 724-731.
  11. C. Branca and C. Di Blasi, Devolatilization and combustion kinetics of wood chars, Energy & Fuels, 17 (2003), 1609-1615.
  12. Gronli, M. G., Varhegyi, G., Di Blasi, C. Thermogravimetric analysis and devolatilization kinetics of wood, Industrial and Engineering Chemistry Research, 41 (2002), 4201-4208.
  13. Di Blasi, C., Branca, C., Santoro, A., Gonzalez Hermandez, E., Pyrolytic behaviour and products of some wood varieties, Combustion and Flame, 124 (2001), 165-177.
  14. Di Blasi, C., Gonzalez Hernandez, E., Santoro, A. Radiative pyrolysis of single moist wood particles, Industrial and Engineering Chemistry Research, 39 (2000), 873-882.
  15. Di Blasi, C., Branca, C., Kinetics of primary product formation from wood pyrolysis, Industrial and Engineering Chemistry Research, 40 (2001), 5547-5556.
  16. Branca, C., Di Blasi, C., Horacek H., Analysis of the combustion kinetics and thermal behavior of an intumescent system, Industrial and Engineering Chemistry Research, 41 (2002), 2107-2114.

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