Abstract Wet limestone-gypsum flue gas desulfurization (FGD) technology is currently the most widely used process. In order to optimize the wet limestone-gypsum FGD system, a coal-fired boiler of 2×135MW units of a thermal power plant was taken as the research object and the mathematical model of wet limestone-gypsum FGD system was established based on the theory of double membrane. The process and the mechanism of the gas-liquid mass transfer and chemical reaction in desulfurization process were described in detail. By comparison, it was found that the calculation results were in good accordance with the industrial operation data, and the effects of several key factors on the desulfurization efficiency were investigated. The calculated results indicated that the desulfurization rate increased with higher liquid/gas ratio or the pH value of the slurry. Increasing the SO2 partial pressure or flue gas flow at the inlet would lead to the decrease of the desulfurization rate. The concentration of Cl- in the circulating slurry should not exceed 21 300 mg/L.
