The Design And Debugging Of DCS In Wet Limestone FGD Control System

With the development of industrial level, the environment problem is becoming more and more serious. According to the statistics, at present, the primary source of air contaminants is still the SO2,which are created by the burning of coal. Therefore, the Ministry of Environment has put forward a series of policies to strengthen pollution control of thermal power plant in this year. These policies force those power plant to reform and improve, which has been equipped with desulfurization system but not reached the standard, others without the desulfurization system must create a new one. In the field of desulfurization device control, wet limestone flue gas desulfurization DCS control technology, have been used widely in the control of flue gas owing to its unique advantages.This paper based on a 2 x 300 MW direct air-cooling heating unit wet limestone flue gas desulfurization system as the research object. First of all, discussed the environmental challenges that China’s power industry is faced with, as well as the development trend of domestic and foreign flue gas desulfurization technologies. Then focused on the principle of FGD technology, and introduced the process of each system with the picture based on the EDPF- NT + system platform.Secondly, basing on the EDPF- NT +system platform, the architecture and function of DCS are analyzed, including DAS, MCS, SCS, ECS. In the implementation part of the system, will focus on the design of pH control loop and SCS optimization. By comparing two traditional control strategies, closed-loop cascade control method is adopted owing to it can adapt large delay and inertia. In the SCS optimization, by increasing the judge of process status improve the reliability of the system.Finally, this article elaborated the debugging purpose and commission of this desulfurization DCS system, analyzed some problems and solutions, and offered some data obtained from the 168-hour test run. This article is able to provide a reference to similar DCS testing projects.