On the characteristic heating and pyrolysis time of thermally small biomass particles in a bubbling fluidized bed reactor Articles uri icon

publication date

  • November 2020

start page

  • 312

end page

  • 322

volume

  • 160

International Standard Serial Number (ISSN)

  • 0960-1481

Electronic International Standard Serial Number (EISSN)

  • 1879-0682

abstract

  • Pyrolysis of crushed olive stone particles in a lab scale Bubbling Fluidized Bed (BFB) reactor wasinvestigated. The time evolution of the pyrolysis conversion degree of the olive stone particles, while moving freely in the BFB, was determined from the evolution of the mass of olive stones remaining in thebed, measured by a precision scale holding the whole reactor installation. The experimental measurements of the pyrolysis conversion degree were employed to validate a simple model combining heattransfer and chemical kinetics, which is valid for thermally small particles. The model combines the Lumped Capacitance Method (LCM) and the simplified Distributed Activation Energy Model (DAEM) toaccount for heat transfer and pyrolysis chemical kinetics, respectively. The estimations of the combined LCM-DAEM model for the pyrolysis conversion degree were found to be in good agreement with the experimental measurements for the pyrolysis of olive kernels in a BFB operated at various bed temperatures,fluidizing gas velocities, and biomass particle size ranges. From the combined LCM-DAEM model, the characteristic heating time and the pyrolysis time of the olive stone particles were derived, obtaining a direct relation between these two parameters for constant values of the bed temperature.

keywords

  • olive stones pyrolysi; bubbling fluidized bed (bfb); characteristic heating time; characteristic pyrolysis time; distributed activation energy model(daem); lumped capacitance method (lcm)