Modeling and Parameter Identification of FCCU Regenerator with Modified Levenberg-Marquardt Algorithm

Fluid catalytic cracking unit (FCCU) is one of the most important secondary processing units in refinery process. Normally a traditional FCCU consists of a reactor and a regenerator, which correspondingly convert heavy oil to valuable products and recover catalyst activity. Compared with reactor, the reactions taking place in regenerator are slow processes. Therefore, the dynamic modeling of an industrial regenerator has always been a hot topic of the studying of refinery process. In this paper a mathematical model of industrial regenearator is built in platform gPROMS on the premise of some assumptions in consideration of real equipment and its operation. The unknown parameters in mathematical model are identified under steady-state operation by a modified LM method with random generated damping factor in order to get a more accurate model. Due to the strong nonlinearity and complexity the model in gPROMS can not be solved under arbitrary initial point, an automatic initialization process is added before model solving to decouple mass balance and energy balance. The dynamic simulation is based on an industrial FCCU in a petrochemical refinery Co., Ltd. in Jiangxi, China with real industrial operational data.