Nonlinear Modeling And Optimal Control Algorithm Of Bed Temperature System In A Circulating Fluidized Bed

With the gradual reduction of high quality coal resources and the continuous improvement of environmental standards,the development of the pulverized coal furnace will be greatly restricted.The research on the combustion and utilization of inferior coal is the focus of research in recent years.Many new and high efficiency combustion technologies are gradually developing and popularizing.The technology of circulating fluidized bed is one of the best among them,which has the advantages of high combustion efficiency,wide selection of fuel and low nitrogen oxide production.The above advantages can achieve efficient utilization of resources and clean combustion.We can predict that CFB boilers will occupy an indispensable position in the future development of thermal power plants.In this paper,the structure and combustion characteristics of CFB boiler combustion system are analyzed.The main characteristics include large inertia,strong coupling and nonlinearity.The bed temperature is an important parameter in the production and operation of a circulating fluidized bed boiler,which directly affects the safety and economy of the unit.The mechanism modeling is very mature,but the model established by this method is too complex to be suitable for the optimization of the controller.Therefore,before discussing the control strategy,through the method of modeling,using historical data to establish the circulating fluidized bed unit of a power plant under different working conditions of fuel quantity,bed temperature and a wind-bed temperature transfer function,and the use of historical data and the identification of independent model is validated,in order to ensure the correctness of the transfer function.The purpose of this study is to find a better control strategy for the efficient control of the bed temperature system of a circulating fluidized bed boiler.On this basis,according to the characteristics of bed temperature objects,fuzzy control,adjustable factor fuzzy control and PID control are adopted in sequence.Finally,a fuzzy self-tuning PID temperature control strategy is put forward.By comparing with other control methods,it is proved that this method can achieve the desired control effect and meet the requirements of the stability and real time of the bed temperature control system.Intelligent algorithm is not only able to improve the automation level of bed temperature control system,but also improve energy efficiency and reduce greenhouse gas emissions.