A study was performed to clarify the mechanisms of limestone dissolution in sulfuric and sulfurous acids, which is important in the wet method of flue gas desulfurization. The mass-transfer characteristics of a benzoic acid plate of fixed area were first tested in a dissolution vessel, and then the dissolution rates of limestone plates in sulfuric acid, sulfurous acid, and gypsum-saturated sulfuric acid were measured and correlated with various factors such as agitation speed in the vessel. The results obtained for sulfuric acid were as follows: the dissolution rate of limestone is controlled by the diffusion in the film formed on the solid surface, of which the diffused component is dissolved limestone in region I (C-H2SO4 < 2x10(-2) mol.m(-3)), sulfuric acid in region II (2x10(-2)

Keywords:Wet Method of Flue Gas Desulfurization;Limestone;Gypsum;Sulfuric Acid;Sulfurous Acid;Mass Transfer;Dissolution Rate