Wet flue gas desulfurization using alkaline agents

The continued great dependency on fossil fuels entails increasing SO2 emissions to the atmosphere, with damaging consequences to both the local environment and the global climate. Thus, during the last years, the tightening of emission control policies has fostered the research over more efficient and sustainable removal technologies. The aim of this review is to present, as extensive as feasible, the origin and development of flue gas desulfurization (FGD) technology, especially of the wet type, using alkaline agents. From the early findings of the harmful effects of SO2 to the gradual establishment of the current legislations worldwide, the deployment of FGD technology has been supported on understanding the mechanism of reaction and the nature of the desulfurization process, giving place to several configurations. A special analysis was made to the limestone/lime method as well as to the magnesium-based process, highlighting the main features and advances. The use of alternative absorbents is also presented along with a comprehensive analysis on the parameters and control variables affecting the process as well as on the management of residues and solid wastes.