TRANSIENT SULFATION BEHAVIOR OF LIMESTONE PARTICLES IN AN AFBC TEST RIG: DATA FOR VALIDATION STUDIES

摘要

Intraparticle conversion profiles and evolution of pore structure with time were investigated by exposing essentially non-porous limestone particles with an average size of 0.655 mm to reaction conditions in a 0.3 MWt atmospheric fluidized bed combustor (AFBC) operating under steady state conditions with and without limestone addition. Structural analyses of the partially sulfated particles show that both the surface area and pore volume increase at the early stages of the reaction but later pore volume remains nearly constant while BET surface area progressively decreases due to the blockage of smaller pores by the bulky reaction product, calcium sulfate. Correspondingly, the pore size distributions indicate a progressive shift toward larger pore diameters. The particles were also examined by means of SEM-EDX analysis technique in order to determine their intraparticle sulfation profiles. The analyses demonstrate that the conversion profile starts from a maximum at the particle surface and decreases progressively toward the product layer-core interface.