A thermogravimetric study of the sulfation of limestone and dolomite—the effect of calcination conditions

Abstract A pressurized thermogravimetric analysis system, constructed to operate with corrosive gases and connected to a programmable calculator used as a data acquisition system, has been used to study the isothermal reaction of sulfur dioxide with limestones and dolomites at pressures from 1.01 x 10 5 Pa to 1.01 x 10 6 Pa (1 to 10 atm), and temperatures from 750 to 1050°C. The sulfation reactions have been studied (a) under conditions where calcium carbonate is the stable form of the reacting solid, and (b) where calcium oxide is the stable form of the sorbent. The data show that both sample size and gas flow-rate strongly influence the observed kinetics. However, the dominant influence on the sulfation reaction of calcined sorbents is the carbon dioxide pressure in which the stone is originally calcined. The results are discussed in the light of previous studies on the sulfation of lime, and the application of this reaction to pollution abatement by removal of sulfur dioxide from hot gases.