Interactions between chemical reactions and the attrition of sorbent particles

Attrition of two different limestones after calcination and sulphation in fluidized beds has been studied by a combination of experimental techniques. The aim is to shed light on the interactive processes of sorbent attrition and the change of mechanical and morphological properties associated with the progress of chemical reactions. Two experimental techniques have been used to characterize different breakage mechanisms occurring in different sections of industrial fluidized bed reactors. Abrasive attrition is characterized in situ by collection of elutriated fines as they are generated during fluidized bed calcination and sulphation of limestone. Fragmentation under high velocity impact conditions is studied ex situ by means of single particle impact tests on pre-conditioned samples at room temperature. The comparison of results from the two experimental techniques has indicated clearly the effects of process history on particle structure and strength. Simultaneous calcination and sulphation leads to reduced impact damage, when compared to subsequent calcination and sulphation.