Fluidized bed combustion of high-volatile solid fuels: an assessment of char attrition and volatile matter segregation (Contributo in atti di convegno)

Type
Label
  • Fluidized bed combustion of high-volatile solid fuels: an assessment of char attrition and volatile matter segregation (Contributo in atti di convegno) (literal)
Anno
  • 1999-01-01T00:00:00+01:00 (literal)
Alternative label
  • R. Chirone, A. Marzocchella, P. Salatino, F. Scala (1999)
    Fluidized bed combustion of high-volatile solid fuels: an assessment of char attrition and volatile matter segregation
    in Proc. of 15th Int. Conf. on Fluidized Bed Combustion, Savannah, USA
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • R. Chirone, A. Marzocchella, P. Salatino, F. Scala (literal)
Pagina inizio
  • 185 (literal)
Pagina fine
  • 201 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Dipartimento di Ingegneria Chimica - Università di Napoli \"Federico II\" Istituto di Ricerche sulla Combustione - C.N.R. (literal)
Titolo
  • Fluidized bed combustion of high-volatile solid fuels: an assessment of char attrition and volatile matter segregation (literal)
Abstract
  • A simple lumped-parameter model of a bubbling fluidized bed combustor fuelled with high-volatile solid fuels is presented. The combustor is divided into three sections: the dense bed, the splashing region and the freeboard. Material balances on fixed carbon, volatile matter and oxygen are set up, taking into account fuel particle fragmentation and attrition, volatile matter segregation as well as postcombustion of both carbon fines and volatiles escaping the bed. A basic assumption of the model is that the combustion pathway that goes from the raw fuel to the combustion products proceeds via the formation of three phases: volatile matter, relatively large non-elutriable char particles and fine char particles of elutriable size. The study is complemented by a simplified thermal balance on the splashing zone taking into account volatiles and elutriated fines postcombustion and radiative and convective heat fluxes to the bed and the freeboard. Results from calculations with either low- or high-volatile solid fuels indicate that low-volatile bituminous coal combustion takes place essentially in the bed mostly via coarse char particles combustion, while high-volatile biomass fuel combustion occurs to comparable extents both in the bed and in the splashing region of the combustor. Depending on the extent of volatile matter segregation with respect to the bed, a significant fraction of the heat is released into the splashing region of the combustor and this results into an increase of temperature in this region. Extensive bed solids recirculation associated to bubble bursting/solids ejection at the bed surface together with effective gas-solids heat transfer promotes thermal feedback from this region to the bed of as much as 90% of the heat release by volatile matter and elutriated fines afterburning. (literal)
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