Comminution of carbons in fluidized bed combustion

Evolution of the Structure and Mechanical Strength of a Coal Particle During Combustion in the Atmosphere of Air and the Mixture of Oxygen and Carbon Dioxide / Ewolucja Struktury Oraz Wytrzymałości Mechanicznej Ziarna Węgla Podczas Spalania W Atmosferze Powietrza Oraz Mieszaninie Tlenu I Dwutlenku Węgla

“…The results obtained clearly indicated the mechanical changes of the coal during its combustion, particularly at the moment of ignition of the char. Moreover, the results correlate very well with the processes of coal comminution that have been described by other authors (Basu, 1999;Chirone et al, 1991) during combustion in the circulating fluidized bed and also explain the sudden change of susceptibility to erosion in the conditions with and without combustion. The measured values can be used as strength parameters in the modelling of the mass loss of coal particles in conditions of circulating fluidized bed combustor that are hard to describe.…”

“…Otrzymane rezultaty wskazują na bardzo wyraźne zmiany wytrzymałościowe węgla podczas jego spalania, szczególnie w chwili zapłonu karbonizatu. Uzyskane wyniki bardzo dobrze korelują z opisywanymi przez innych autorów procesami rozdrabniania węgla (Basu, 1999;Chirone et al, 1991) podczas spalania w warunkach cyrkulacyjnej warstwy fluidalnej. Tłumaczą gwałtowną zmianę podatności na erozję w warunkach bez spalania oraz z towarzyszącym spalaniem.…”

A model of coal combustion dynamics in a fluidized bed combustor

“…The distinction pertains to the degree of fragmentation the particle experiences when it first enters the combustion chamber. Chirone et al [7] survey recent fragmentation research, including work describing size dependent characteristics in bituminous coals. For Indiana bituminous coal, small particles do not Augment whereas large particles readily fragment.…”

“…When large particle bituminous coal enters a fiuidized bed, some particles by thermal shock and devolatization -occurs quickly [7], and the resulting fragmented particle distribution guides the impulse response. As such, the effective initial mass distribution is the fragmented mass distribution [12].…”

“…In the laboratory, "monodispersed" samples actually comprise particle distributions wide enough to significantly affect transient responses. Furthermore, when large-particle bituminous coal is introduced into a fluidized bed combustor, some particles fragment [7], creating a wide initial particle distribution. This fragmented particle distribution has a profound effect on the transient COj response.…”