Research On PH Automatic Control System For Wet Flue Gas Desulfurization Of 330MW CFB Unit

In recent years,China's power industry has developed rapidly,and the corresponding environmental pollution problems have caused widespread social concern.The government has paid more and more attention to power environmental protection.Sulfur dioxide emitted by coal-fired power plants is the main component of atmospheric pollutants.Limestone-gypsum wet flue gas desulfurization is currently the most widely used desulfurization method.The pH value of gypsum slurry plays an important role in the safe and economic operation of the desulfurization system.This paper analyzes and designs the pH automatic control system for a 330 MW circulating vulcanization bed unit wet desulfurization system in a power plant.The main contents of this paper are as follows:(1)This paper introduces the development of flue gas desulfurization technology and the research status of pH control system,discusses the principle of flue gas desulfurization,and explains the influence of pH value on desulfurization efficiency.(2)Taking the wet desulfurization system of 330 MW circulating vulcanization bed unit in Jingtai Power Plant of Inner Mongolia as the research object,based on the historical operation data of the desulfurization system,the pH control system was analyzed and improved,and a new cascade feedforward-feedback control system was designed.According to the material balance theory,the slurry flow rate is calculated in the way of fixed molar ratio,which serves as feed-forward control,and the feedback control strategy is designed based on the principle of internal model control.Apply the improved control logic to the actual DCS and analyze the operation data and effect before and after the improvement.The results show that the improved system can be put into automatic operation stably,which effectively improves the control quality.(3)Data mining method is used to optimize the setting value of pH control system.The FCM algorithm and CA algorithm of association rule data mining method are compared.Finally,the CA algorithm is used to mine the optimal setting value of the pH control system,so as to improve the economy while satisfying the desulfurization efficiency.