The Research And Design On Desulphurization Control System In The Thermal Power Plants

According to incomplete statistics, China has the largest emissions of sulfur dioxide in the world at present, and the acid rain has contributed to the serious pollution in the environment. Then the economic losses of each year have reached as high as 10 billion yuan of above. At the same time, the acid mist, which is made by sulfur dioxide and water vapor, has done harm to human health seriously with an increased morbidity and death rate of respiratory diseases. Around 60% of sulfur dioxide in industrial emissions comes from the coal-fired power plants, and with the high development of economy and people’s pursuit for the better life, the national thermal power installed capacity will increase by more than 100 million kilowatt until2020. Therefore, measures must be taken to the desulfurization process of flue gas emissions from coal-fired power plants as soon as possible. And it plays an important role to develop an advanced and scientific power plant desulphurization control system with reasonable control strategies.Flue gas desulfurization system has many characteristics, such as the complex control process, the big control points and the large diffusion space of equipments and so on. Thus the Distributed Control System which is used to control the whole work is based on automatic control technology with computer technology and communication network technology to realize the scheduled technological requirements and desulfurization result.After analyzing the principle of flue gas desulfurization and process flow, we can devide the whole system into the pulping system, absorber system, limestone gypsum dewatering system, process water system and so on. In the meanwhile, we should make accurate control strategies of each subsystem to guarantee the safe and reliable established function of the system.The hardware structure of the whole system consists of field equipment layer,process control layer and production management layer. Therefore, the design of the hardware should be devided into the operator station design, field control station design and selection of important smart meter to realize the purpose of the system that includes the control and detection of the equipment, acquisition and processing of data, analog closed-loop and sequence control, chain safeguard and so on. At last, the address settings of all the hardware are finished according to the design of hardware.The design of system software includes the procedures as follows. Firstly, we complete the configuration of hardware, operator station and control station, as well as parameter setting, distribution mode, programming, testing, fault diagnosis and the control algorithm of task. Then, in order to realize the monitoring and intelligent management of flue gas desulfurization system, we design a friendly man-machine operation monitoring interface with perfect function.In order to guarantee the safe and reliable work of system, we complete the power equipment inspection, single machine commissioning and whole machine commissioning in turn. At last, we analyze the result of desulfurization, which indicates that the operation of control system is stable and reliable, and the desulfurization effect is good.