Study On The Advanced Control Strategy Of Delayed Coking Unit

Delayed coking is a well-developed processing technology of vacuum residue,and takes a key role in the oil refining industry.In recent years,in order to increase the production level of delayed coking unit,a lot of oil refining enterprises improve advanced control technology.However,because of some characteristics of delayed coking unit,such as intermittent operation,non-linear,time-varying,strong coupling and so on,it is difficult to describe the dynamic model accurately.Available advanced control strategies based on linear model are not suitable for strongly non-linear process control,and it is also difficult to analyse the stability and robustness of system,so we need to set its parameters to ensure stability in the operation.It results in the deterioration of system performance and operating slowly.The paper as the background for the delayed coking unit which produce 1.2 million tons Ethylene per year,in Liaoning huajin Chemical(Group) Co.,Ltd., studies advanced control strategies based on non-linear model in the delayed coking unit to resolve the lack of advanced control strategies based on the linear model.First,the paper analyse the research status and problems of control technologies of delayed coking unit at home and abroad,and studies predictive non-linear control strategies based on neural network depend on the characteristics and request of the process of Delayed coking unit.The paper applied the LM algorithm as the optimization algorithm to nonlinear predictive control and designs the fuctions of the reaction system and the main fractionator multivariable non-linear predictive controller.Second,applied discrete neural network process to the measurement of soft chemical process,and applied variable gradient learning algorithm which corrected with Fletcher-Reeves to discrete neural network process to improve the speed of training neural network.It achieved good results to simulate it with MATLAB softwareFinally,the paper gives the criterion of the selection of instrumentation and the architecture,hardware configuration,software configuration of control systems of delayed coking unit,depend on control strategy and soft measurement technology and engineering the actual situation of projects.