Sulfation reaction between SO2 and limestone: application of deactivation model

Among the several efficient methods for in combustion sulfur dioxide removal methods, sulfation with carbonate based systems are the most widely used one due to its low cost. In this study sulfation reaction kinetics was investigated using limestones of different origin. Limestones pre-calcinated at 900°C in inert atmosphere were subjected to 0.35% by volume SO2. It was observed that sulfation reaction rate was high in the early stages. The conversion for the sulfation of Kinik and Goynuk limestones increased with increasing reaction temperature. For temperatures of 850°C and lower the sulfation reaction was in kinetic control regime. The occurred pore plugging caused a considerable decrease in the rate of sulfation with the extent of the reaction under the all studied conditions. For the sulfation reactions carried out at high temperatures, the model estimating the increase of activation energy with conversion were found to be in agreement with the experimental data. Activation energies of the sulfation reactions for Kinik and Goynuk limestones were estimated around 12 179 and 11 543 cal/mol, respectively. Deactivation model gave good estimates of the conversion especially at high sulfation reaction temperatures.