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

Selectivity and Microkinetic Insights on Ethylene Oligomerization over Ni Encapsulated in a Brønsted-less Hollow ZSM-5 Zeolite

by Abed, Mohamed, khairova, Hita, Velisoju, Morlanes, Meijerink, Emwas, Vernuccio, Castaño
ChemCatChem Year: 2025 DOI: https://doi.org/10.1002/cctc.202500957

Abstract

We encapsulated Ni nanoparticles in a hollow ZSM-5 zeolite catalyst using the dissolution-recrystallization method to catalyze ethylene oligomerization. Our aim is to engineer an idealized catalyst free of Brønsted acid contributions to kinetics or deactivation, having isolated and encapsulated Ni2⁺–zeolite species, to study the intrinsic oligomerization kinetics on Ni2⁺–zeolite through an experimental and microkinetic standpoint. We proved how the hollow architecture encapsulates both Ni2⁺ and NiO species, being the former significantly more active and selective toward dimerization. A comprehensive microkinetic model, grounded in the Cossee-Arlman mechanism and parameterized using experimental data, provides a detailed understanding of the reaction network on isolated Ni2⁺ sites. The model reveals that while linear butene formation dominates, its selectivity decreases with increasing ethylene conversion, temperature, and pressure, highlighting the contribution of isomerization pathways at elevated temperatures. This study focuses on the method to develop isolated oligomerization sites and then studies the intrinsic microkinetic pathways and rates.

Keywords

OLG MKM HCE