Joana Fernandes

Closed-loop dynamic behavior of an industrial high-efficiency FCC unit

Although the control of an FCC plant includes all the hardware components of the process, it is at the FCC reactor-regenerator system that the control is the most critical. This is mainly due to the strong interaction between the reactor and regenerator units. As a result, the reactor-regenerator system presents a highly nonlinear behavior and is therefore a challenge for control tasks. This paper presents a brief introduction to the control of a high-efficiency FCC unit and the implementation of the main regulatory control loops in the reactor-regenerator system of a real Portuguese industrial high- efficiency FCC unit. Moreover, closed-loop dynamic simulations performed with a model previously developed by the same authors, are compared to industrial dynamic data from step tests done in GalpEnergia FCC unit showing that this FCC simulator can realistically represent the closed-loop dynamic behavior of a real industrial operating unit. Therefore, this dynamic model has a great potential to be used as a reference model for advanced model-based control and real-time optimization purposes.

Mechanistic Dynamic Modelling of an Industrial FCC Unit

Abstract The aim of this study is to obtain a model that can simulate the performance of an industrial Fluidised Catalytic Cracking (FCC) unit in steady and dynamic state and which will subsequently be used in studies of control and real time optimisation. In this paper, a dynamic model for a R2R type FCC unit is presented. The model includes the riser, the stripper/disengager, the regeneration system and the catalyst transport lines. Mass, energy and pressure balances are performed for each of these sections. Simulation results for steady and dynamic states are presented and compared qualitatively with those from previous FCC models.

Multiplicity of steady states in an UOP FCC unit with high efficiency regenerator

Abstract Static bifurcation in a FCC unit is a problem that arises whenever studying the control of a FCC unit. The origin of this behavior is usually due to the exothermicity of the catalyst regeneration reactions and to important phenomena of backmixing in the regenerator. For this reason the geometrical and operational design of the regenerator unit plays an important role in the overall performance and dynamic stability of FCCs. Prior work has focused on model and control problems of different operating FCC units. However, none of these studies have considered a FCC unit with high efficiency regenerator. This paper presents an analysis of the static bifurcation behavior of an UP FCC unit with high efficiency regenerator. The results show that the high efficiency regenerator presents static bifurcation exhibiting multiple steady states, depending on the operating conditions.