Research On The Application Of Distillation Based On Fuzzy Expert System

The paper takes DCH-300molecular distillation device as its research object, which discusses the intrinsic mechanism and distribution control of molecular distillation process. The real-time control of molecular distillation process with OPC technology and fuzzy PID control in Simulink is realized.Firstly, a brief of overview of the development and research significance of the molecular distillation technology is given. The basic principle of molecular distillation technology is studied. The experiment on the affecting factors of producing distilled water is researched, and the evaporator temperature is the main affecting factor for the purity of the distilled water. Experimental results show that there is nonlinear and time-varying relationship between the evaporator temperature and distilled water purity, so the traditional control methods isn’t suitable for producing distilled water. The fuzzy PID controller combined with expert experience is designed for real-time control of the evaporator temperature to produce the higher purity distilled water.Secondly, the molecular distillation DCS is designed based on PLC by DCS is introduced on the DCH-300molecular distillation device. Three-level distillation process is distributed control and centralized management according to the characteristics of the DCH-300distillation process. In field control layer, two independent and interrelated subsystems are used. The communication between the subsystems uses MPI bus for data exchange, and communicated the S7-300PLC in the process control level. The communication between S7-300PLC and IPC in producing control level uses PROFINET, and this data communication system as the basic of molecular distillation DCS.Finally, evaporator temperature is set with the fuzzy expert thought. Based on OPC technology the real-time data exchange between Simulink and S7-300PLC is implementation by WinCC as the server, Simulink as the client. The real-time control of evaporator temperature with fuzzy PID control in Simulink is realized and achieves application of intelligent control on the industrial control system.