The Research And Application Of Kiln Calcination Process Control System

Cement rotary kiln is the key equipment of dry production line of cement clinker.Cement raw materials processed into cement clinker by calcining the raw material in the rotary kiln.The calcination process is a thermal reaction process with nonlinear and strong coupling characteristics.Therefore it is difficult to ensure the accuracy of control system.At present,the domestic cement enterprises mainly rely on the experience of the operator to control the rotary kiln.And some cement company use the traditional PID algorithm to control the equipment,but the effect is not very ideal.With the proposed of the model predictive control and multiobjective optimization,we can take full advantage of these algorithm in the control system of cement rotary kiln to improve the quality of the cement,to optimize the coal consumption,and to reduce the pollution to the environment.In this paper,we combined the model predictive control algorithm with a multi-objective optimization algorithm based on the industrial and control mechanism for cement rotary kiln.And we have applied the combination method into the cement rotary kiln control system.Based on the actual project,we design the DCS control system of cement rotary kiln and predictive control expert system.The specific research work are as follows:Firstly,researching the coupling relation of the parameters of the cement rotary kiln and the mechanism of calcination process,it can reveal the intrinsic mechanism affecting the power consumption of rotary kiln cement production and stable operation.The main control parameters of control system of rotary kiln were determined,which provides the basic mechanism model for the rotary kiln process control.Secondly,using the model predictive control method and the variable constraint reduced steady orbit variation within the cell,it can reduce the coupling error effectively.At the same time,using the lexicographic multi-objective algorithm to optimize the objective function,which has applied to the control system of cement rotary kiln.Additionally,we design the rotary kiln DCS process control system based on SIEMENS PCS7 and the actual project.And we build the DCS process control system hardware structure using DCS hardware,industrial Ethernet and profibus technology.And we build the function block software based on the PCS7 technology.The function block can realize the function of monitoring whole control system.Finally,we design the operation and management of application platform based on OPC technology,using Visual C# to develop the expert system software based on themodel predictive control.Using OPC communication technology,it can realize DCS communicate with other equipment and expert system software system,and it can realize the online optimization control of cement rotary kiln.The predictive control software system has been applied in Jiangjin Limited by Share Ltd Jidong Cement cement production line.The software system has optimized the process,and reduced the energy consumption per unit of cement clinker to.