A fast fluidized bed reactor for industrial FCC regenerator

Filho, R. Maciel; Batista, Leônia Maria; Fusco, Mozart

doi:10.1016/0009-2509(96)00039-5

Cited by 9 publications

(5 citation statements)

References 5 publications

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“…However, profiles of gas compositions vary along the riser depending on the flow and mixing pattern assumptions in the dense bed. In Figure 4a,b simulations from Jober et al [134] show uniform gas composition in the dense bed while simulations from other workers [18,131,132] show gas profiles increasing for carbon dioxide and decreasing for Oxygen with the height of the dense bed. This is because the former has assumed wellmixed conditions for gases in the dense bed while the latter has assumed plug flow conditions for gases in the dense bed.…”

Section: Fcc Regenerator Performance Predictionsmentioning

confidence: 83%

“…The moles of hydrogen per mole of carbon in coke from catalytic cracking of gas oil were reported to vary between 0.4 and 2.0 [32,39]. Simulations of workers [131,132,134] showed that the CO composition leaving the dense bed is higher than zero, but this CO is almost always converted into CO 2 by the time it reaches the regenerator cyclones in the freeboard. This 'afterburn' reaction demonstrates the importance of including the freeboard in the FCC regenerator model.…”

Section: Fcc Regenerator Performance Predictionsmentioning

confidence: 99%

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A Review of Modelling of the FCC Unit—Part II: The Regenerator

et al. 2022

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Heavy petroleum industries, including the Fluid Catalytic Cracking (FCC) unit, are among some of the biggest contributors to global greenhouse gas (GHG) emissions. The FCC unit’s regenerator is where these emissions originate mostly, meaning the operation of FCC regenerators has come under scrutiny in recent years due to the global mitigation efforts against climate change, affecting both current operations and the future of the FCC unit. As a result, it is more important than ever to develop models that are accurate and reliable at predicting emissions of various greenhouse gases to keep up with new reporting guidelines that will help optimise the unit for increased coke conversion and lower operating costs. Part 1 of this paper was dedicated to reviewing the riser section of the FCC unit. Part 2 reviews traditional modelling methodologies used in modelling and simulating the FCC regenerator. Hydrodynamics and kinetics of the regenerator are discussed in terms of experimental data and modelling. Modelling of constitutive parts that are important to the FCC unit, such as gas–solid cyclones and catalyst transport lines, are also considered. This review then identifies areas where the current generation of models of the regenerator can be improved for the future. Parts 1 and 2 are such that a comprehensive review of the literature on modelling the FCC unit is presented, showing the guidance and framework followed in building models for the unit.

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Section: Fcc Regenerator Performance Predictionsmentioning

confidence: 83%

Section: Fcc Regenerator Performance Predictionsmentioning

confidence: 99%

A Review of Modelling of the FCC Unit—Part II: The Regenerator

et al. 2022

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“…They had examined the effects of various modeling assumptions on the development of industrial FCC regenerator models. Later, in similar manners, Faltsi‐Saravelou et al,8 Filho et al,9 and Lu10 modeled the FCC regenerators with different simplifications in the reaction kinetics or hydrodynamics. In these models, the grid zone (the region with a short distance above the distributor) was usually treated differently from the above bubbling zone for its much larger interphase mass‐transfer rate.…”

Section: Introductionmentioning

confidence: 98%

A practical countercurrent fluid catalytic cracking regenerator model for in situ operation optimization

Zhang

Li³

2011

AIChE Journal

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A practical countercurrent fluid catalytic cracking (FCC) regenerator model with improved descriptions of gas and solid flow patterns is proposed. A three-zone and two-phase gas model was utilized to describe the gas flow through the regenerator, addressing the different phase mass-transfer properties in the different zones. A new two-continuously stirredtank reactor-with-interchange model was used to describe the solid flow and to address the effect of freeboard on catalyst regeneration. Otherwise, this model also considered the usually adopted expanding section for reducing solid carryover. The model was programmed in Matlab language with coupled hydrodynamics and reaction kinetics models and tested and validated by the data from an industrial FCC regenerator operated under both partial and full CO combustion modes. After fitting a single model parameter, the interchange solid flux between the dense bed and freeboard, the model predictions were in reasonable agreement with the commercial data for both modes. Figure 12. Effects of air flow rate (a1, b1), solid inventory (a2, b2), and operating pressure (a3, b3) on carbon content in the regenerated catalysts under partial and full combustion modes.

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“…Guigon and Large (1984) applied a two-phase flow model to a multistage regenerator. Filho et al (1996) explored the influence of the air jet near the regenerator air distribution grid.…”

Section: Introductionmentioning

confidence: 99%

Numerical Approaches for a Mathematical Model of an Fccu Regenerator

Penteado

Negrão

Rossi

2008

RETERM

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This work discusses a mathematical model of an FCCU (Fluid Catalytic Cracking Unit) regenerator. The model assumes that the regenerator is divided into two regions: the freeboard and the dense bed. The latter is composed of a bubble phase and an emulsion phase. Both phases are modeled as a CSTR (Continuously Stirred Tank Reactor) in which ordinary differential equations are employed to represent the conservation of mass, energy and species. In the freeboard, the flow is considered to be onedimensional, and the conservation principles are represented by partial differential equations to describe space and time changes. The main aim ofthis work is to compare two numerical approaches for solving the set of partial and ordinary differential equations, namely, the fourth-order Runge-Kutta and implicit finite-difference methods. Although both methods give very similar results, the implicit finite-difference method can be much faster. Steady-state results were corroborated by experimental data, and the dynamic results were compared with those in the literature (Han and Chung, 2001b). Finally, an analysis of the model’s sensitivity to the boundary conditions was conducted.

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A fast fluidized bed reactor for industrial FCC regenerator

Cited by 9 publications

References 5 publications

A Review of Modelling of the FCC Unit—Part II: The Regenerator

A Review of Modelling of the FCC Unit—Part II: The Regenerator

A practical countercurrent fluid catalytic cracking regenerator model for in situ operation optimization

Numerical Approaches for a Mathematical Model of an Fccu Regenerator

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