In existing wet flue gas desulfurization(FGD) systems

pH value is usually used to control the acid-base reaction process

but there is a lack of control indicators for the redox process. In this study

oxidation-reduction potential(ORP) is used as a control indicator for redox reaction control in desulfurization systems

and the scientific significance of this regulation is pointed out. Experimental simulations of the redox reactions in the wet desulfurization process are carried out at first. Then

by combining the experimental data with the classical Nernst equation

an ORP semi-empirical equation suitable for the redox reaction of the wet FGD system is established. The correlation coefficient of the fitted curve is determined to be 0.98

with a maximum error of less than 4.2 mV. The Eh-pH diagram of the S-H_2O system at 50 ℃ is plotted

and the optimal range for regulating ORP is derived to be 100～300 mV after considering the influence of the presence of other elements. Finally

a regulation and control scheme is given to achieve the optimization of the FGD system by changing the oxidation air volume

which provides theoretical support for introducing ORP as the optimization control indicator for wet FGD systems.