Dissolution kinetics of sorbents and effect of additives in wet flue gas desulfurization

Flue gas desulfurization (FGD) technology has been adopted by a number of power stations for the removal of sulfur dioxide (SO2) from flue gas. The wet FGD system is the most commonly used process because of high SO2 removal efficiency and because of the availability of the sorbent used. This paper emphasizes the wet FGD process and the different types of sorbents used. Sorbent dissolution in the wet FGD process plays a significant role in the overall performance of the system. Factors such as temperature, solid-to-liquid ratio, pH, particle size, and additives can be optimized to improve the dissolution rate in the wet FGD system. Additives such as organic acids and inorganic salts can improve the dissolution rate and the desulfurization efficiency of the sorbent. Dissolution kinetics gives an understanding of the effects of reaction variables on the dissolution rate. The dissolution process is a heterogeneous reaction system consisting of fluid reactants and solid particles. This is best described using the shrinking core model that considers a reducing solid particle size as the reaction takes place.