Limestone Attrition under Simulated Oxyfiring Fluidized‐Bed Combustion Conditions

Abstract

Limestone attrition by surface wear was studied during the flue gas desulfurization under simulated fluidized-bed (FB) oxyfiring conditions and hindered calcination. Bench-scale experimental tests were carried out using well-established techniques previously developed for the characterization of sulfation and attrition of sorbents in air-blown atmospheric FB combustors. The experimental limestone conversion and attrition results were compared with those previously obtained with the same limestone under simulated air-blown combustion conditions. The differences in the conversion and attrition extents and patterns associated with oxyfiring as compared to air-blown atmospheric combustion were highlighted and related to the different particle morphologies and thicknesses of the sulfate layer. It was noted that attrition could play an important role in practical circulating FB combustor operation, by effectively enhancing particle sulfation under both oxyfiring and air-blown combustion conditions

A Population Balance Model on Sorbent in CFB Combustors: The Influence of Particle Attrition

“…Transfer from the L to the SL phase, driven by sulfation. It has been discussed ,, that sorbent sulfation in FB combustors takes place along two subsequent stages (Figure ): stage I , associated with the initial buildup of a sulfate-rich particle shell, and stage II , associated with a slower attrition-enhanced sulfation promoted by continuous removal of the sulfated material from the particle surface. Assuming that the contribution to SO 2 capture given by stage II is negligible, the global sulfation kinetic constant used in the model has been estimated by averaging over the time the sulfation rate in stage I measured during differential FB experiments …”