The New Automatic Dosing Control System Research For Circulating Cooling Water

Nowadays, lack of resources and environmental degradation problems have become increasingly prominent, water conservation has become a grim task that every country will be faced. Circulating cooling water for the blood of industrial enterprises, accounting for industrial water consumption of70%. But its repeat cycle of a low utilization rate, emissions created by the waste and pollution is widespread. In comparison with foreign countries, China’s Circulating Water treatment technology is relatively backward, especially those of the mature, Pharmacy prescription excellent programs and automatic control technology combining the research and application is still in the infancy stage.The project is sponsored by National Natural Science Foundation (No.50806010), and also supported by Jilin province Science and Technology Development Project (No.20100432). This paper mainly includes two aspects of contents:the circulating cooling water automatic dosing control system design and tuning PID controller parameters based on system identification method.The part of automatic dosing control system for circulating cooling water:The feedback parameters of the system are fouling thermal resistance, corrosion rate, as well as key water quality parameters. The system uses ICP I-7000series distributed I/O modules as the core unit of the signal transmission and processing, adopt ACS355with internal built-in PID controller as a system control unit and apply mechanical diaphragm metering pumps as the main implementing agency to design the automatic dosing control system electric. In accordance with automatic dosing control program, the system uses the Delphi7.0development platform to prepare in the software. Finally, this project constitutes a set of cycle cooling water automatic dosing control system with on-line monitoring and automatic dosing.The part of tuning PID controller parameters based on the system identification method:According to the industry experimental data, research the mathematical model of the automatic dosing control system using system identification method to fet mathematical model (transfer function) of the system. This paper studies the PID control simulation of the system applying the Matlab/Simulink software. In the simulation environment, this paper sets the system PID control parameters according to the Stable Boundary parameter tuning formula. And then the PID control parameters are used in the production practice. According to comparing the simulation results with actual data, this paper gets the ideal PID parameters finally.