Experimental Research And Application Of Wet Desulfurization Based On ORP And PH Coupling Control

The wet limestone-gypsum flue gas desulfurization process is the most widely used desulfurization technology in thermal power enterprises.The reactions in the desulfurization system include two parts,the acid-base reaction and the oxidation reaction.The existing control mode is to adjust the pH to ensure that the acid-base reaction proceeds.Guarantee the desulfurization efficiency;the oxidation reaction is not accurately controlled during the whole process,which will cause a series of problems such as excessive sulfite levels,system scaling,high heavy metal valence,and poor gypsum quality.Therefore,how to scientifically control the oxidation process of the desulfurization system scientifically,while maintaining high desulfurization efficiency,efficiently control the oxidation of calcium sulfite,prevent scaling of the desulfurization system,control the valence of heavy metals,generate high-quality gypsum,and reduce desulfurization The energy consumption of the system is a prominent problem to be optimized in the current thermal power plant desulfurization system.This subject explores the characteristics and laws of pH and ORP changes during the oxidation process of calcium sulfite through the idea of coupling control of ORP and pH.From the basic principles that affect the oxidation reaction of the desulfurization system as the starting point and the end point,the introduction of ORP as the control parameter of the desulfurization system Coupling control with pH.Rely on the real-time parameters of monitoring ORP and pH to understand the oxidation state of the desulfurization slurry,and adjust the oxidation state by changing the amount of oxidizing air.During the analysis of the oxidation status of the desulfurization slurry,the scale products and precursors of the desulfurization system were sampled and analyzed,and the collected samples were analyzed by XRD,SEM,EDS,ICP-MS,TG and other characterization methods to investigate the wet The common scale types and formation mechanism of the process desulfurization system,and targeted scaling prevention methods are proposed.In laboratory conditions,the effects of temperature,air volume,pH,reactant concentration,and stirring speed on ORP were studied through orthogonal experiments of L₁₆（4⁵）,and various factors were analyzed during the wet desulfurization slurry oxidation process.The influence of ORP.Through the analysis of variance,the contribution order of each factor to the ORP oxidation process in different slurries was obtained.The research results provide theoretical support for model research and oxidation control of desulfurization slurry.Based on a large amount of experimental data in the laboratory,combined with the classic Nernst equation,an ORP semi-empirical formula suitable for the redox reaction of the wet desulfurization system was established,and the model was evaluated for accuracy.During the fitting process,the coefficient was determined to be 0.98,and the maximum error was less than 8m V.Install ORP measuring instrument and oxidation fan frequency conversion controller in a power plant,and verify the effect of ORP and pH dual control on site.Field tests show that the dual control of ORP and pH can effectively improve the reaction status of the desulfurization system,reduce the scaling of the desulfurization system,and improve the quality of gypsum.The ORP semi-empirical formula is modified by the obtained field test data,and an ORP semi-empirical formula suitable for the actual wet desulfurization system is obtained.The model and improved model fitting point determination coefficient is 0.91,and the model and the overall experimental data point determination relationship is 0.76.In this study,an accurate control scheme for wet desulfurization based on ORP and pH coupling control was achieved,which overcomes the lag of traditional oxidation control and optimizes the operation of the desulfurization system.It has solved many shortcomings in traditional oxidation control through an integrated approach and has good development prospects.