Comminution of limestone during calcination and sulphation in a bubbling fluidized bed combustor

Comminution phenomena occurring during calcination and sulphation of an Italian limestone (Massicci) in an atmospheric bubbling fluidized bed combustor, operated at 850°C, were investigated, with particular attention to the interaction between chemical reaction and mechanical stresses. The attrition rate of the sorbent was characterized for different diameters and masses of limestone and sand. No fragmentation of the sorbent particles was found. The attrition rate resulted proportional to the mass of limestone and inversely proportional to the mean diameter of the particles. The attrition constant of calcined limestone turned out to be one order of magnitude larger than that of sulphated sorbent.