A two‐dimensional model for simulation, control, and optimization of FCC risers

Why FCC riser is taller than model predictions?

“…Most of them report that catalytic cracking of hydrocarbon reaction are very fast and conversion takes place within 10-15 m from the inlet of an industrial scale riser. 3,6,[9][10][11] However, Derouin et al 12 observed that actual plant conversion of gas oil and gasoline yield continues to increase significantly up to about 35 m. They correlated industrial data using axial dispersion model, but pointed out that several Additional Supporting Information may be found in the online version of this article.…”

“…However, deviation was quite prominent in the inlet and exit regions. They used more rigorous fluid dynamic equations based on particulate phase fluctuating energy explained by Gidaspow,16 but took the simplest three-lump model proposed in a twin article by Weekman et al 17,18 Applying a conservative approach, Souza et al 11 considered 2-D flow with six lumps. However, the continuity and momentum equations were greatly simplified due to assumptions of incompressible homogeneous mixture with laminar flow.…”

The inverse methodology of parameter estimation for model adjustment, design, simulation, control and optimization of fluid catalytic cracking (FCC) risers

“…Therefore, there is a need for methods that could be capable of producing sufficiently accurate numerical results from FCC riser mathematical models for any feedstock type, catalyst, and riser operating conditions. Souza et al 13 suggested one possible way of classifying the different FCC riser models based on their direct industrial application. Thus, a FCC riser model (fluid flow and/or kinetic) can be used for: (i) the development of a major model where the simulations of the entire conversion FCC plant is considered; (ii) testing or studying of specific catalytic cracking phenomena, such as catalyst deactivation, adsorption, kinetic models, etc.…”

“…They are also used to compare the mathematical models with the experimental data, providing a more comprehensive understanding of the physical phenomena. 2 In this work, the advance in knowledge is characterized by two objectives: (i) to introduce a general methodology with the potential for adjusting existing simplified FCC riser models to any feedstock type, catalyst and riser operating conditions through the inverse methodology of parameter estimation, and (ii) to demonstrate the use of a calibrated model of the third type, 13 according to the classification presented in the previous paragraph, through the simulation of an actual size industrial FCC riser, predicting concentrations and temperatures profiles from the bottom to the top of the riser, operating with different design and operating conditions from the laboratory-scale multi-purpose riser 15 for which the kinetic model 12 was adjusted to a specific feedstock type/catalyst set.…”

“…For the first application, the models simulate not only the riser, but also other equipments like the regenerator and the stripper. 14 It is very important to have a fast solution for the riser model, 13,15 and also to be able to determine coke formation during the cracking reactions as a separate lump. This information will later be used by the regenerator model to determine the energy produced from coke burning and also the temperature of the regenerated catalyst.…”