Temperature of chlorinated kettle is a very important factor for chlorination reaction. However, the chlorinated kettle temperature is difficult to be controlled because of the characteristics of temperature, such as time-delay, nonlinear and time-varying, the influence caused by the inflow of chlorine and the unstable site situations. The truth is that manual operation or traditional PID control, which is adopted by the domestic chlorinated polyethylene manufacturers, cannot obtain a satisfactory control effect. Therefore, an effective method for chlorinated kettle temperature control is proposed and put into real application. On the basis of the analysis of the chlorinated reaction equipment characteristics as well as the difficulties of chlorinated reaction temperature control, the advanced control algorithm is proposed, in which combines the fuzzy-PID control algorithm with the Smith predictor control. After analyzing the input-output characteristics of the chlorinated kettle, the least squares algorithm with forgetting factor is applied to establish the system model. Meanwhile, a “re-identification” performance index is formulated according to the accuracy of model. The model identification method is combined with the performance index in order to provide a precondition for the compensation of Smith predictor. Furthermore, based on Siemens PCS7 system, the hardware configuration as well as the control algorithm software modules is designed, and the corresponding human-machine interaction interface is realized via WinCC software. In this way, a process control system for chlorinated kettle temperature is completed. This scheme preforms effectively, promotes the quality of chlorinated polyethylene products，and ensures the stable production of chlorinated polyethylene as well.
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