Control Strategy Study And Control System Design Of Industrial Boiler

With the rapid development of modern industry technology,the demanding of high energy efficiency has become urgent increasingly.As one of the important equipment,the boiler transforms the primary energy into secondary energy,whose control and management level also improve gradually.However,in our country, most of the boilers are also controlled by instrumentations and relays,even manual work,which can not be satisfied the request.Therefore,through by using advanced control technology,the boiler control system is not only can guarantee the safety in production,but also can save the energy and improve efficiency,which has good market development and investment prospect.The boiler drum water level is usually influenced by the factors such as changes of load,access water speed,water quality etc,which has time delay, nonlinear and other features.The fuzzy adaptive PID controller is designed,which consists of two inputs(e,ec)and three outputs(K_P,K_I,K_D).The purpose is to improve the shortcomings of PID control parameters,which tuning difficultly and adapting poorly.On this basis,the host controller of the three impulse cascade control system is adopted by fuzzy adaptive PID controller,and the deputy controller is used PI controller.Simulation indicates that the drum water level control system can achieve a smooth adjustment and the water level always maintaines the required fluctuation range when the changes of load are relatively small or dramatically.The burnning control system of industrial boiler includes steam pressure control,the furnace negative pressure control and the control of optimal air-coal ratio in general.Its parameters are time-variation,non-linear,complex interference factors,coupling seriously,the mathematical model is difficult to be determined. According to these characteristics,the methods of vapor pressure,furnace negative pressure and optimal air-coal ratio which are controlled respectively by the fuzzy adaptive PID,feedforward PID and fuzzy self-optimizing are proposed.Simulation results based on the MATLAB show that the three control algorithms have good control effect,reduce the overshoot,enhance the rising time,reduce the adjustment time.In this paper,the boiler DCS control system based on profibus,industrial ethernet,PLC and monitoring software is designed,which realizes distributed control and centralized management.Fuzzy adaptive PID and fuzzy self-optimizing are embedded into PLC and configuration software,as well as intelligent MATLAB algorithm is integrated into WinCC configuration software seamlessly by using OPC technology,which adapt complex condition of the boiler with serious non-linear,large thermal inertia,many disturbance factors.