The Design Of Automatic Control System For Polyvinyl Chloride Production

The distributed control system is widely used in electric power,chemical industry,metallurgy and other industries.With its intuitive operation interface and convenient background configuration,which are widely sought after among users,it can realize automatic control of dangerous processes.Tangshan LJ Co.Ltd.Phase III project was established in 2018 and built in 2019.According to the company's overall demand for the system,combined with the process,instrumentation,electrical and other professional joint research and decision,Yokogawa CENTUM VP control system was finally favored,which realizes the functions of automatic feeding,polymerization control,blanking,drying and crushing packaging,it can realize the control of remote monitoring and display instruments,reducing the workload of on-site craftsmen,ensuring the production safety of the enterprise and improving production efficiency.Deeply analyzed the production process of the polyvinyl chloride for instrument control and a clear control idea.The hardware and software design of Yokogawa CENTUM VP control system is determined and completed by comparing the control mode and cost performance.The flow regulation loop of VCM feeding and catalyst feeding and reaction temperature of polymerizer are designed.By setting the change value of reaction heat as feedforward compensation,the problem of temperature lag is solved by adopting feed forward which control and cascade control.The flow regulation loop of vinyl chloride monomer and initiator feeding were designed.The temperature stability control loop of polymerization reactor was mainly established.The change value of reaction heat in polymerization reactor was set as feedforward compensation.The feed-forward control and cascade control methods were used to solve the temperature lag problem.By establishing the mathematical models of kettle temperature,jacket water temperature and cooling water flow,the automatic control of kettle temperature without manual intervention is realized by using the modeling and simulation function of MATLAB.At the same time,the cascade control effect is better than single loop PID control,which has guiding significance for production.The optimized design of PVC production process meets the requirements of automatic control of PVC production.Either the polyvinyl chloride feeding control or the polymerization reaction temperature control is more stable,which ensures the reliable operation of the system.Figure 43;Table 5;Reference 53...