Research And Development Of Polymerization Temperature Control System Based On PROFIBUS

At present, the polymerization of polymer production is largely by batch chemical reactor, which is a kind of widely uses vessel in chemical production. The reaction mechanism is much complicated. Because of its large time-variant, non-linear and time-delay characteristic, It's extremely difficult to build a precise mathematical model. Temperature is one of the most important parameters which has great influence on the polymerization in production. It is necessary to studying the methods of controlling the temperature of polymerization, which can largely promote quality and quantity of production. So it has great significance on the production of chemical industry.This paper is based on the national "863" project managed by a chemical plant. We design a polymerization temperature control system based on PROFIBUS-DP. The system with IPC-PLC pattern distributive structure is composed of host operation station, hypogynous-machine control station and field instrument. The host operation station which is made up of IPC, iFIX configure software and database is used to monitor the whole producing process. The hypogynous-machine control station which used Siemens S7-300 PLC and field instrument are to accomplish field control and data collection. The advantage of this control system is friendly HMI, easily operation and directly reflection of the field working status.On the control arithmetic aspect, under the analysis of chemical reactor's heat-conduction characteristics, we have concluded the controlled-object's attribute and come up with a intelligent compound controlling scheme based on temperature measurement. Further more, the paper discusses the feasibility of this control strategy, Meanwhile, we have analyzed and compared the effect of the regular PID control and fuzzy self-adaptive PID control with matlab. And then, we study how this control scheme is applied to chemical reactor process. At last we provide software and hardware realization process. After this system put into use, it runs very well with better stability and higher reliability, and it is also effective in control temperature.