Research On Temperature Modeling And Control Of Tunnel Kiln

Tunnel kiln is a kind of high temperature equipment which is used for refractory products production, and the control level of temperature directly affects the production and quality of refractory products. Therefore, the temperature control strategy is an important research content in the tunnel kiln control system. How to design the temperature control strategy for tunnel kiln which can meet technical requirements, improve product quality, reduce energy consumption and reduce pollution is of great importance.The thesis takes the practical project as the background, at first, according to the requirement of the produce process of tunnel kiln and the characteristic of tunnel kiln, a control system for tunnel kiln is designed which contain loop control, process supervising and management information system. The control system selects SIMATIC S7-300 to achieve loop control function to collect and control temperature, pressure and flux, selecting the configuration software of WINCC to achieve the supervisory and management function of system, which carry out the function of monitoring of flow chart, real-time and historical trend and real-time alarm, vehicle basic information management, printing of reports, etc.In order to study the temperature control strategy of the tunnel kiln, the temperature model is established at first. Because tunnel kiln is very complicated, it is difficult to establish an accurate mathematical model. According to the characteristics of the tunnel kiln, the second-order plus lag time model of the tunnel kiln is identified by using LS based on the data from the field, and the temperature model is proved to be effective.The principle and characteristics of PID control and Fuzzy control are introduced. On this basis, considering the engineering application, a new Fuzzy-PID controller combining the advantages of fuzzy controller with PID controller is designed to increase the control effect of the tunnel kiln’s temperature, which consists of incremental PID controller and incremental Fuzzy controller. The controller takes the fuzzy controller when the error, which is the difference of the given and feedback value, is large and takes the traditional PID controller when the error is small.According to the process of tunnel kiln, the control of the kiln’s temperature is simulated when the given value of tunnel kiln’s temperature changes and the vehicle is moved by using PID controller, Fuzzy controller and Fuzzy-PID controller in turn which are created by Simulink in Matlab, the simulation results show that the Fuzzy-PID controller has the best control performance which has faster response speed, no error and no overshoot, which approves the feasibility of this method.