Abstract: Using carbide slag to replace limestone as desulfurization agent is a new technology turning wastes into treasures. Take the example of the 600-MW unit of a power plant, where limestone was previously utilized as desulphurization agent. The experimental study on the usage of carbide slag as desulfurization agent is carried out. The effects of different pH values on the desulfurization efficiency and the gypsum quality are analyzed respectively, and the economic performance of carbide slag and limestone as desulfurization agent are compared as well. The study results show that the performance of carbide slag as a desulfurization agent is satisfactory with the corresponding cost greatly reduced. However, the water contents may rise in the byproduct gypsum, which makes it necessary to enhance the pretreatment of the desulfurization agent and optimize the design of gypsum dewatering system.

Key words: power plant, flue gas desulfurization, limestone, carbide slag