SO2 absorption by a fixed calcite bed

Abstract

When burning high-sulfur fuels, calcite is added to a furnace to reduce SO2 emissions. Calcite and the resulting calcium sulfite start to cake above temperatures of 700°C, adversely affecting SO2 bonding and complicating the problem of mathematically simulating the process. The catalytic burning of fuel enables us to lower the maximum temperature of fuel combustion from 1200°C to 700°C. This reduces the caking of materials and allows the use of simple calculation models. The aim of this work is to create a simplified model of the kinetics of the observed process, based on experimental data obtained using a reactor with a fixed calcite bed at temperatures of 500–600°C. According to the model, SO2 absorption is a second-order reaction (first order with respect to SO2 and to free sites capable of SO2 bonding), and the fraction of free sites falls linearly as the quantity of absorbed SO2 grows. The kinetic parameters of the model are determined, i.e., the reaction rate constant and maximum calcite capacity with respect to SO2.