Research And Application Of Integrated Control System For Silicone Production

Organic silicon is an important part of the new chemical materials industry, known as "industrial vitamins" and "technology catalyst", and it is widely applied in the field of automotive, textile, paper making, machinery, electronics, construction, metallurgy, chemical industry and medical treatment. However, the production capacity of China’s organic silicon is generally low, and the product quality is not high. To a certain extent, this is because many of our factories use relay logic control system, which has low degree of automation, low-level data management, poor control accuracy and high operating costs. This paper aimed at achieving organic silicon production’s process automation for the good yields and high quality based on the design of integrated control system.In the first place, this paper introduced the development of control science and practical application in chemical production, which provided the foundation for the selection of appropriate control strategies to complete my research and design of integrated control system,and then described the working process of organic silicon production line and proposed the solutions and control requirements against the problems of artificial production mode.According to the process requirements, the overall design of integrated control system was done with distributed control system as a model, including the management of the PC layer, the lower machine control layer and the on-site equipment layer. This paper did a scientific study on the control of organic silicon production process. Reaction kettle temperature control system can complete the logical sequence control, temperature control, pressure control, flow control, to realize automatic integrated operation of the reaction process and achieve the temperature control target. Condenser variable frequency constant pressure water supply system can achieve self-regulating water flow using inverter control of pump according to the change of condensation reflux ratio, which is efficiency and energy saving. Distillation kettle quality control system can realize product quality control by controlling the rectifying section temperature so that different components of can be separated in sequence.Reactor temperature is the most critical factor affecting the yield and quality of products,Different products were achieved at different temperatures, and product composition proportion is also different, so it needs to keep constant optimum temperature to obtain the optimal product quality. This paper focused on the reactor temperature control system in which built a relationship model between reactor temperature and cooling water flow based on the principle of heat balance and obtained model parameters with using MATLAB to deal with experimentaldata according to the step response dynamics. We designed a fuzzy-PID controller based on Smith predictor to solve the problems of time-delay, non-linearity, and complexity of the temperature control system with using a Smith predictor to relieve the time-delay, a fuzzy controller to improve the response speed, and a PID controller to reduce the steady-state error.With these improvements, we achieved better control effect. We did unit step response simulations of the conventional PID-Smith control, fuzzy-PID control and the fuzzy-PID control based on Smith predictor with using Simulink, and finally verified the control performance in some theoretical degree by the simulation comparative analysis.Finally, this paper introduces the function design of the control system and implementation steps, and the research results were successfully applied to the actual production. According to the research results and process requirement, we write Siemens S7-300 PLC program to achieve the automatic control of the reaction process and quality control of distillation process; we designed the independent circuit and debugged the parameters of frequency converter built-in PID function to achieve the condenser constant pressure water supply system; we used KingView 6.55 configuration software to realize the functions of PC connection communication,screen display, alarm for security, and historical data query. Through field debugging and commissioning, it improved the yield and quality of organic silicon products and protected the safety in production.