Research On Bed-Temperature Control System Of Circulating Fluidized Bed And Its Parameter Optimization

With the development of social economy and city’s booming in China, urban have produced a lot of sewage and sludge which have a large number of toxic substances. So it is piled up at will to exist the high secondary pollution risk. Circulating fluidized bed has many advantages to burn sludge such as high efficiency, low pollution, wide adaptability. Burning sludge process quickly and sludge has small volume after processing. Sludge has calorific value after dehydration. Therefore, there is more and more attention concerning using circulating fluidized bed to burn sludge.This thesis takes the seven lattice sewage treatment plant in hangzhou one hundred tons per day sludge incineration project as the research background. And it make a deep research on circulating fluidied bed bed-temperature control system. Bed-temperature is directly influenceable the boiler’s parameters that decide the boiler to operate continuous safety whether or not. And Bed-temperature is related to calclum than sulfur, the emissions of nitrogen oxides and carbon oxide. Through the analysis of hangzhou seven lattice sludge characteristics, it contains a large amount of calorific value after dewatering and it’s opposite with huabei bituminous coal’s combustion characteristics. Therefore, the dosing quantity of sludge can properly change that is useful to reduce auxiliary fuel. Through the research of sludge and coal mixed to burn, the paper get sludge weighless curves with different proportions of sludge and coal. The paper also analyzes the factors that affect bed-temperature and construct the bed-temperature control system, and establish the model of the bed temperature control systeml. Circulating fluidized bed bed-temperature control system is a complex system with the character of time delay and time-varying. In order to control bed-temperature more precise and avoid its fluctuations, the thesis introduces automatic gain balance smith predictor to improve time delay for the system a bad effect. At the same time, for the bed-temperature control system’s parameters have a large change range and the system require a high accuracy. However, the site field person change parameters only according to their experience that need much time and energy to try repeatedly. In the practical application, the system need to adjust PID parameters to obtain the optimal controller parameters of the effect. Therefore, the paper introduces genetic algorithm on the basis of automatic gain balance smith predictor to optimize temperature controller’s parameters.Finally, the author uses the matlab to simulate the bed-temperature control system whenthe parameters of the system occurres major fluctuations, and analyze the bed-temperature tracking property of automatic gain balance smith predictor with genetic algorithm to optimize bed-temperature controller’s parameters. The simulation results indicate that the control algorithm to the control system in this paper can achieve good control effect.