Studies of ignition behaviour of biomass particles in a down-fire reactor for improving co-firing performance

Article English OPEN
Li, Jun ; Paul, Manosh C. ; Czajka, Krzysztof M. (2016)
  • Publisher: American Chemical Society
  • Related identifiers: doi: 10.1021/acs.energyfuels.6b01065
  • Subject:
    arxiv: Physics::Plasma Physics | Physics::Atmospheric and Oceanic Physics | Physics::Chemical Physics

To realize large percentage biomass co-firing with coal in existing coal-fired boilers, the combustion behaviour of biomass is expected to be similar or comparable to that of coal. When co-firing with coal, biomass is not necessarily to be ground as fine as the dedicated coal particles due to its higher reactivity. With aim of achieving promising performance of co-firing with dedicated coal particles, the determination of suitable particle size of biomass becomes important. The paper investigates experimentally the ignition behaviour of three biomass materials in a down-fire reactor associated with thermogravimetric analyser (TGA). TGA results showed that the devolatilization process is accelerated by the presence of oxygen, but failed to identify the impacts of particle size on the ignition behaviour of biomass. However, the ignition testing results based in the down-fire reactor clearly showed that ignition delay time of a large biomass particle is longer than that of smaller one. In addition, being injected into the furnace, the softwood particles take a longer residence time to be ignited than the straw particles at same sizes, which agrees well with their reactivity analysis in TGA. Moreover, the ignition test results suggested that the ignition mechanism of biomass could be alternated from homogeneous to the heterogeneous ignition when the furnace temperature is increasing; at high enough furnace temperatures, the ignition predictably occurs at the particle surface without requiring the start of devolatilization. The results quantitatively demonstrate the effects of particle size on the ignition delay time of biomass, which, together with the transport phenomena and surrounding atmosphere, can contribute to control the biomass combustion profile and co-firing performance.
  • References (23)
    23 references, page 1 of 3

    (1) IRENA-ETSAP%20Tech%20Brief%20E21%20Biomass%20Co-firing.

    (2) Zhang, D.-k.; Wall, T. F. An analysis of the ignition of coal dust clouds. Combust. Flame 1993, 92, 475−480.

    (3) Katalambula, H.; Hayashi, J.-i.; Chiba, T.; Kitano, K.; Ikeda, K.

    Dependence of Single Coal Particle Ignition Mechanism on the Surrounding Volatile Matter Cloud. Energy Fuels 1997, 11, 1033− 1039.

    (4) Grotkjaer, T.; Dam-Johansen, K.; Jensen, A. D.; Glarborg, P. An experimental study of biomass ignition. Fuel 2003, 82, 825−833.

    (5) Jones, J. M.; Saddawi, A.; Dooley, B.; Mitchell, E. J. S.; Werner, J.; Waldron, D. J. Low temperature ignition of biomass. Fuel Process.

    Technol. 2015, 134, 372−377.

    (6) Riaza, J.; Álvarez, L.; Gil, M. V.; Khatami, R.; Levendis, Y. A.; Pis, J. J.; et al. Ignition behavior of coal and biomass blends under oxyfiring conditions with steam additions. Greenhouse Gases: Sci. Technol.

    (7) Toptas, A.; Yildirim, Y.; Duman, G.; Yanik, J. Combustion behavior of different kinds of torrefied biomass and their blends with lignite. Bioresour. Technol. 2015, 177, 328−336.

    (8) Li, J.; Brzdekiewicz, A.; Yang, W.; Blasiak, W. Co-firing based on biomass torrefaction in a pulverized coal boiler with aim of 100% fuel switching. Appl. Energy 2012, 99, 344−354.

  • Metrics
    No metrics available
Share - Bookmark