Assessment of catalyst deactivation model for sulfur retention in fluidized bed combustors

An improved version of a combustion-desulfurization model for fluidized bed combustors burning high ash and sulfur content low quality lignite in its own ash with the addition of limestone is presented. The desulfurization mo del considers sulfur retention by both limestone and ash and is based on fi rst order catalyst deactivation where the kinetics of desulfurization is de scribed by two rate constants; one for the initial surface reaction, the ot her for the rate of pore plugging or deactivation. The accuracy of the comp lete model with experimentally determined deactivation rate constants was t ested by applying it to a 0.3 MWt AFBC test rig and comparing its predictio ns with measurements. Comparisons show that the model produces reasonably a ccurate predictions of sulfur retention provided that the rate constants ar e determined experimentally under the fluidized bed combustor operating con ditions.