Multiscale kinetic modeling in catalysis ⇒ from microkinetics to computational fluid dynamics and process simulations

Problem statement

We envision multiscale modeling as critical enablers of reaction understanding, catalyst and reactor design, scale-up, and process optimization. The framework includes predicting the molecular reaction mechanism at the molecular level to the process optimization stage. As catalytic processes occur at the multiscale, we address these issues individually and collectively.

At the microkinetic level, our models resolve the rates of the individual elementary steps, rate-determining step (RDS), adsorption, and desorption mechanisms. We use quantum chemical calculations (density functional theory, DFT) to support our assumed kinetic pathways, original parameter estimations, and adsorption-desorption energies.

We incorporate thermodynamic constraints into our models. Once developed, the microkinetic model could guide the catalyst and reactor design. We also have experience developing Langmuir-Hinshelwood and Eley-Rideal types of kinetic models.

At the macrokineitc level, we develop lump-based and empirical models which, in some cases, are very robust and, together with other models, can be used to extract information such as mechanism change, optimize conditions, or for reactor pre-design.

We couple hydrodynamics, heat transfer, and reaction kinetics at the reactor level in computational fluid dynamic (CFD) simulations. Together with optimization algorithms, we aim to improve operating scenarios, develop innovative reactor prototypes, and predict process behaviors at the industrial scale.

Goals

  • Microkinetics I ⇒ key thermodynamic relationships
  • Microkinetics II ⇒ fitting, training, and optimization
  • Microkinetics III ⇒ ab initio kinetic modeling
  • Macrokinetics ⇒ complex reaction networks and population balances
  • CPFD ⇒ reactor modeling and scale-up
  • CFD ⇒ reactor modeling and optimization
  • CFD II ⇒ modeling operando reactors
  • Process system engineering ⇒ gPROMS

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Related Publications

Regulating the crude oil–to–chemical process in a multizone fluidized bed reactor using unconventional catalyst formulations

by Cui, Dikhtiarenko, Kulkarni, Shoinkhorova, Al Aslani, Alabdullah, Mazumder, Medina Flores, Alahmadi, Alfilfil, Morales-Osorio, Almajnouni, Gascon, Castaño
Powder Tech. Year: 2024 DOI: https://doi.org/10.1016/j.powtec.2024.119573

Abstract

Crude oil catalytic cracking to petrochemicals in one step is a profitable pathway for future refineries yet it has significant hurdles. We investigated adding silicon carbide to the formulation and adjusting the crude oil–to–chemicals process in a multizone fluidized bed reactor by improving the morphology for hydrodynamics and thermal conductivity for heat transfer to promote the catalytic cracking performance. First, we synthesized and characterized catalysts with various SiC sizes and contents to select the best based on morphology. Then, we compared this catalyst against an industrial benchmark catalyst using computational particle fluid dynamics to understand the catalyst circulation and heat transfer in realistic crude oil–to–chemicals process conditions. Finally, we performed catalytic cracking experiments using this catalyst and the benchmark under optimal conditions. The higher light olefin yield from the unconventional catalyst formulation validated our workflow for regulating the crude oil–to–chemical process.

Keywords

C2C CRE MKM