| The coal slime filter pressing system in coal preparation plant is an equipment group which can filter and press the coal slurry derived from coal washing process. It is used to product the available coal slime resource and the recyclable coal washing water. And it is a fatal guarantee for production high-efficiency and resource utilization high-efficiency. The short of coal resource and the environment protection urgent need to filter press the coal slurry to realize the use of coal slime and the recycle use of coal washing water. In this text, the coal slurry filter pressing automatic control system was designed and improved based on the frequency conversion control and the intelligent control direct at some problems, such as complex control mode,unstable equipment and incomplete degree of automation.The control of global function of the filter pressing system was realized based on the control of the KM350/2000 fast open type membrane filter press, combined PLC control technology, converter technique, fuzzy-PID control strategy and electrical control technology at Xiaonan coal preparation plant of Tiefa energy group.1、The framework of the control system was designed. The design and selection of PLC system and electrical control and frequency converting control, the selection of transducer and sensors were finished. The network communication of the system was built focused on Siemens S7-300 PLC, used PROFIBUS-DP communication network and Ethernet protocol.2 、 Constant pressure control of the feed pump was realized to guarantee the safety of the filling line and the quality of tray to tape using PID control technology and converter technique. The fuzzy-PID control strategy and the frequency converting control were used to control the pressure constantly of the filter pressing process, in order to guarantee the safety of equipment of filter pressing process and a certain of effect of filter press. And the closed-loop control and the aim of high-efficient and high-quality filter press were realized based on the condition of the flow of filter pressing process.3、The configuration of PLC hardware system, the setting of parameters and the compiling of the programs were finished by the means of STEP7 Basic V5.5 based on hardware and control strategy. The upper computer monitoring picture was designed using MCGS software to control and monitor the operation of equipment and offer a visual operating deck to works.The design and improvement of the control system of the filter pressing was finished in this text, it has great significance and application value for improving the work efficiency of the filter press system, enhancing the quality of the production,saving fabricating cost and environmental protection. |
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