A complete kinetics study of iron oxide catalyzed sulfation has been performed. From the kinetics data, a calculation has been made to estimate the improvement of the performance of a fluidized-bed combustor using Fe/sub 2/O/sub 3/ coated sorbent. For Tymochtee dolomite, with 1.08% (by weight based on CaO contained in sorbent) Fe/sub 2/O/sub 3/ coated on uncalcined stone, it has been shown using the MIT FBC model that for 90% sulfur retention, a 40% reduction of the sorbent requirement is achieved over the uncatalyzed case. In other words, Ca/S ratio = 2.5 for the uncoated stone, whereas Ca/S = 1.5 for the coated case, for the same sulfur retention. Although the Fe/sub 2/O/sub 3/ coating procedure works well for Tymochtee dolomite, it has an inhibiting effect on the Greer limestone. This is a result of plugging of pore mouths. A complete study (both modeling and experimental) has been done to show the interplay of the two opposing effects: increase in chemical rate by Fe/sub 2/O/sub 3/ and decrease in pore diffusion rate due to plugging. A complete study of the kinetics of the reaction between Greer limestone and NO under combustion gas conditions has been made. The reaction becomes quite reversible, i.e., the NO concentration in combustion gas approached the equilibrium value, at slightly above 400/sup 0/C. The thermodynamic equilibrium values have been measured with TGA. Basic kinetics data were gathered, which may be used for reactor design. 8 references, 35 figures, 10 tables.