Build The Control Model And Develop The Modeling Software For The FCCU Based On The Mechanism Analysis

The Fluid Catalytic Cracking Unit (FCCU) which is important in petroleum processing is one of the core unit for the petroleum refining now. And the most important part of the unit is the reaction-regeneration system, in which the reaction mechanism and the dynamic process is complex. As a result, it's become a challenge for the industry process control. Now there are lots of advanced control algorithms are applied to the units in order to achieve higher economic efficiency, but we have to get the dynamic model of the unit before we do that. So there are lots of researchers work hard for modeling the FCCU.Firstly, this paper introduces the development of the FCCU technology in order to know the sorts of FCCU which are using in refinery factories and the current situation. The catalyst is one of the factors which restrict the development of the FCCU, so the introduction is necessary for the development of the catalyst. Then do some investigation to understand the application of industry process control for the FCCU. Finally the Coaxial-type and previa coke burning FCCU are selected as the reach object. After analysis the features of the two type units, the model method based on the mechanism analysis is chose. Then the raw materials and products are divided into five lumps in order to model the mechanism of the two type units. The mechanism model is so complex that it can't be suitable for the application of control, therefor it is necessary to simplify the built model by analysising the process of the FCCU.There are two problems need to be handled in order to apply the control model to the actual unit. The first is that there are some parameters can not be directly measured, so we have to use the parameter estimation to get these parameters; The second we faced is that there are lots of control systems are based on the linear system theory now, so we should use the linearization methods to deal with the built model in order to get the linear state equations. In the part of the parameter estimation, firstly summarize the the methods of parameter estimation, then chose the least square method to estimate the parameters according to the features of FCCU and show the detailed procedure of parameter estimation for the Coaxial-type FCCU. In the linear processing, because of the consideration of the unit's delay factor and the control model got is a non-affine nonlinear system, the paper adopts the conventional linear method named Taylor expansion for the convenience of deal with the equations. The detailed linear process is show in this paper, finally a set of industrial data is used to simulate and verify the linear state equations.In the end of the paper, the Visual C++ 6.0 integrated development environment is used to develop the calculation software of the FCCU's control model based on the deducing process and the linearization in the preceding chapters. The software include several parts for example the input measured data of the Coaxial-type and the previa coke burning FCCU, the control model calculation in background, draw the dynamic trends, communicate with the Microsoft Excel and so on. Further, the software can realize the data acquisition more conveniently by the mode of serial port or the OPC client.