| The rectification of Vinyl Chloride Monomer (VCM) is an important technique in the process of making VCM monomer. But there are still some problems, such as big fluctuation, difficult operation, energy waste and so on. With the increase of market competition and the requirement of pollution control, the modification for technique of rectification VCM had been paid more and more attention in recently years.A multi-variable control system for the rectify equipment of VCM is considered as main research objects in this dissertation. The main research work of this dissertation is summarized as follows:(1)The structure and characteristics of a certain type of rectify equipment of VCM is deeply analyzed. The thermodynamics model of the control system for rectify equipment of VCM is formulated. Then the proposal for modifying the control system is determined.(2)The advantage of Distributed Control System (DCS) is analyzed. A modified control system On the basis of DCS for the rectify equipment of VCM is established(3)The operating instruction for actuating and closedown of the control system is proposed. And the proposal for eliminating fault is given. The control system based on DCS introduced in this dissertation can be used to accomplish the control of many circuits, such as reflux at low-boiler tower, heating low-boiler tower, reflux at high-boiler tower, heating tower tank and condensation of finished product.The control system has been used in some chemical enterprises. Some intuitive, flexible graphical configuration tools are employed in the system. The graphical configuration tool has strong function to simplify complex control problems, and has strong adaptability for the variable working conditions. The product quality and production capacity will be improved. |
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