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

Reaction network and kinetic modeling for the direct catalytic cracking of Arabian light crude oil to chemicals

by Al Aslani, Lezcano, Colom, Alahmadi, Shoinkhorova, Dikhtiarenko, Cui, Alfilfil, Morales-Osorio, Almajnouni, Castaño, Gascon
Chem. Eng. J. Year: 2024 DOI: https://doi.org/10.1016/j.cej.2024.154981

Abstract

We investigate the catalytic cracking of Arabian light crude oil into chemicals. A kinetic model has been established for an in-house developed catalyst using a micro-activity testing unit under a wide temperature range (525–650 °C) and various catalyst-to-oil ratios (0–4.14). Our conditions are adjusted to promote light olefins and propylene-to-ethylene ratio. We trained different reaction networks with the experimental data to calculate the kinetic parameters and, at the same time, select a statistically relevant model. The most representative model, with eight lumps and forward–backward first-order reactions, enables the acceptable prediction of the yield of chemicals (light olefins). The obtained kinetic parameters suggest that diesel and gasoline fractions are important intermediates in which forward reactions are preferred due to lower activation energy requirements and faster rate constant. The model was validated by reparametrization using Arabian extra light data.

Keywords

MKM C2C