Preparation of bagasse ash/CaO/ammonium acetate sorbent and modelling their desulphurization reaction

Abstract

The influence of siliceous and hydration agents additives on the preparation of calcium-based sorbents for dry flue-gas desulphurization at low temperature was studied. The key reaction variables investigated are: quantity of bagasse ash, hydration temperature, quantity of ammonium acetate and hydration time. Their effect on the surface area of the sorbent was determined and a central composite design was used as a statistical tool. A polynomial model was established to correlate the sorbent preparation parameters to the sorbent surface area. The desulphurization experiments performed with the thermogravimetric analyser indicate higher SO2 removal when bagasse ash and ammonium acetate are used. The kinetics of desulphurization reaction was fitted using the unreacted shrinking core model and the results show that the rate-limiting step was diffusion over the product layer.