Application Of DCS System In The Flue Gas Desulfurization Project

China’s economic development has entered the post industrialization, the traditional high energy consumption, high pollution production mode has already can’t adapt to the requirements of sustainable development, energy conservation is the inevitable choice of China’s economic development, especially the recent fog and haze weather is getting worse, government focus gradually shifted from the economic growth to pay attention to people’s livelihood, the environmental protection is the priority., SO2 governance is imperative in environmental protection.In order to control SO2 pollution in the atmosphere, people studied desulfurization technology for years. At present people has developed more than 200 kinds of SO2 control technology, Limestone-gypsum is widely commercial used in big power plants currently in the world, the wet desulfurization technology accounted for the largest proportion in FGD technology, Limestone-gypsum technology has mature technology, high desulfurization efficiency, desulfurizer sources readily available, safe and high reliability, etc., in the application of large boiler desulfurization unit basically adopt wet limestone (lime)-gypsum flue gas desulfurization technology.The limestone gypsum method is a complex process of desulfurization, which contains many controlled equipments and objects, and many control objects are complex multivariable control objects. The desulfurization process control is complicated and difficult, The unsafe and the desulfurization efficiency of the control state occur when the instability occurs.This research takes Xuchang Nengxin power plant as an example of limestone-gypsum desulfurization process technolog, for desulfurization process control system, the control system adopts the distributed control system (DCS), Control logic and algorithm for optimizing the key closed-loop control and sequence control of the desulfurization system, monitoring of the impact of the desulfurization efficiency of the key indicators, an important indicator, such as pressure, pH value, temperature and the "logic" and ensure data reliability. The design of the control system follows the principle of automatic detection, automatic adjustment, automatic protection and automatic operation.Through the system debug, the complete control system runs stably, the control state is safe, the desulfurization efficiency is stable and reliable. The system realized the automatic detection, automatic adjustment, automatic protection, automatic operation, reducing the operating personnel misuse and labor intensity, reduce the operating costs, to achieve energy-saving emission reduction effect.