The Research And Application Of Cement Mill Process Control System In Jidong Second Line

For complex process control system of cement mill，because the cement mill itself hasthe time variability, nonlinearity, close coupling among variables and othercharacteristics，it is commonly difficult to establish a accurate model for the cement millsystem and control accuracy is usually difficult to ensure. The production, developmentand continuing mature of predictive control method based on dynamic prediction model,receding horizon optimization and feedback correction, bring a new research direction forthe process control of the cement mill system. For cement grinding technics and thecontrol mechanism of cement grinding process, the article proposes a model predictivecontrol algorithm of cement mill system, and it designs the process control system forcement mill. Specific research efforts are as follows:Firstly, the article elaborates on the research status of cement industry and cement millprocess control system and points out the importance of improvement of cement millcontrol automation level. Through analyzing cement grinding technological process, andfurther studying several typical conditions and control mechanism of cement mill system,various factors that affect the running of cement mill system are clear, the main parametersused for monitoring cement mill system are determined. They provide mechanistic modelbasis for the precise control of cement mill.Then, according to the control requirement of cement mill system, the research ofpredictive control algorithm for single-input single-output systems and multivariablesystems is made, and adjusting method for parameters in the algorithm is analysed indepth.Thirdly, according to characteristics and performance requirements of actual projects,the article designs cement mill process control system using programmable logiccontroller technology, industrial network technology and computer control technology. Torealize the monitoring of the entire system, it adopts ControlLogix5000series PLC assystem controller, configures the master station and I/O remote stations, and usessupporting software to program for upper computer and lower computer softwares.Finally, the predictive control algorithm is applied to the cement mill process controlsystem by configuring an intelligent control station. Step changes are made to the controlsystem for simulation verification and simulation results show that the control algorithm not only has good setpoint tracking property, but also has good robust stability.