Research And Design Of Automatic Control System Of Dense Medium Coal Preparation

Dense medium coal preparation, which has the advantages of wide separation granularity, high efficiency and simple automation realization, is one of the most widely used methods in coal preparation. There are manyinfluential process parameters indense medium coal preparation. But the process parameters are not easy to be controlled for the mutual coupling between different parameters, among which the dense medium coal preparation density is the most important parameter.Based on the background of Jiangzhuang coal preparation plant equipment upgrading and transformation project, this thesis designed a dense medium coal preparation centralized control system on the base of the programmable controller and industrial Ethernet, while the Siemens S7-1500 PLC and industrial computer are the core of the control system.The proposed centralized control system can complete the imformation collection and the control of field device.Furthermore, the lower comupter program and the upper computer interface were designed with the Siemens TIA Portal and the Win CC, respectively.Firstly, this thesis introduces the basic principles of dense medium coal preparation and the process flow. Secondly, mathematical model parameters used in this thesis are determined by analyzing the exsiting mathematical model and the actual producing status of the coal preparation plant. Then, according to the request of control system, a self tuning fuzzy PID controller of dense medium suspension liquid densityis was designed by combining the fuzzy control and PID control. The controlled plant is the dense medium suspension density, while the the initial density was given by the upper computer, and the actual density was obtained by the field X-ray densitometer.In addition,two-dimension fuzzy controller was used with the inputs of dense medium suspension liquid density deviation and error. The parameters ofPK, IK andDK are online adjusted by using the proposed fuzzy rules. At last, the proposed control system was simulated on the platform of Matlab/Simulink while the control program was realized by S7-1500 PLC. The simulation results showed the features of short responding time, little overshoot and good dynamic performace. Control design request are satisfied by the proposed method in this thesis.