KINETIC STUDY OF SULFUR DIOXIDE ABSORPTION INTO DOLOMITE-BRUCITE SUSPENSIONS

Abstract

The influence of the dolomite-brucite concentration and temperature on the global process of sulfur dioxide, SO₂, absorption into dolomite-brucite suspensions was established. According to the proposed macro-kinetic model, the chemical reaction between H₂SO₃ and MeCO₃ takes place into the adsorbed layer, at the outer surface of the granules. The low values of the activation energies obtained, Ea << 25.1 kJ/mol, confirmed for working conditions, that the global chemisorption process was limited to diffusion stage. At suspension concentrations lower than 5% and high temperatures, the chemisorption was carried out according to the shrinking core model without crust, when the diffusion of H₂SO₃ through the liquid phase is the limitative stage. At concentrations higher than 10%, the chemisorption was carried out according to the unreacted core model with crust formation, when the diffusion of H₂SO₃ through the crust of products remains the limitative phenomenon.