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

Related People

Related Covers

Related Publications

Aggregation Kinetics of Technical Catalysts in a Spray-Fluidized Bed

by Alkadhem, Al Majed, Mohamed, Tsotsas, Castaño
Particuology Year: 2026 DOI: https://doi.org/10.1016/j.partic.2026.01.005

Abstract

Size enlargement control and modeling in fluidized beds are crucial in the pharmaceutical and food industries but remain underdeveloped for technical catalyst formulation and shaping. This work uses different modeling approaches to understand aggregation kinetics: single- and two-pathway population balance equation (PBE) modeling and machine learning. These models are trained on a large dataset of experimental results from a bottom spray-fluidized bed, using realistic technical catalyst conditions and ingredients: ZSM-5 zeolite, bentonite, and alumina. Our optimized model is based on a two-pathway PBE with two distinct collision efficiencies for early- and late-stage growth dynamics across nucleation, seed formation, seed aggregation, and layered growth. With this model, we discuss the granulation and agglomeration dynamics of realistic technical catalysts and study the controlled shaping of several case studies with tailored morphologies (50, 100, and 200 μm pellets) under optimized conditions (i.e., maximum yield within the desired particle range) as validation.

Keywords

HCE MKM