Crude Oil Refining System Modeling And Analysis Basing On Hybrid Petri Net

The production activities of the refining system start and end at discrete time points, which have reflected the characteristics of discrete events, the oil refining production process should be regarded as a discrete event. However, the form of the oil is continuous, which leading to the continuity of the refining process. Thus, refining system is a hybrid system which cannot be described by a discrete event model or the continuous model. The short-term production scheduling of the refining system includes continuous random variable constraints, which makes it much more complex. In order to ignore some constraints in the process of modeling to simplify the model, the scheduling method based on mathematical modeling is not feasible and practical usable. Petri Net is capable of modeling and analysis of discrete event dynamic system. However, when the system is complex, using Petri Net to model and analysis lack the consideration of real-time and stochastic. Hybrid Petri Net is a new model of Petri Net based on the traditional Petri Network proposed in recent years. Oil refining system with the complexity of a hybrid system, is more appropriate to use the hybrid Petri Nets to model. This main research work as follows:1.Describe the characteristics of continuous process and discrete process of refining production enterprises. Analyze the various constraints of refining process in the practical situation. use the hybrid Petri Nets as the tool of modeling to analyze the scheduling plan, the process of crude oil unloading, crude oil transportation, oil refining and oil product sales. After satisfying these constraints, the Petri Net model of each part are established, on the basis of which, a hybrid Petri Net model of crude oil processing established.2.Analyze the short-term scheduling of crude oil refining system with time staying constraints and tank switching constraints. There is three charing model: four charing tanks for two distillers, five charing tanks for two distillers, six charing tanks for two distillers.3.Propose a short-term scheduling method which has three steps including determiningthe production rate, distributing the oil to the distillation and adjusting the operation decision order is d. Eventually, introduce a practical case from the refinery and verifies the feasibility and rationality of the proposed method.