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

Hydrodeoxygenation of mixtures of biomass-derived model compound oxygenates over Pt/HY catalysts

by Prabhudesai, Yerrayya, Gurrala, Castaño, Vinu
Chem. Eng. Sci. Year: 2024 DOI: https://doi.org/10.1016/j.ces.2024.119800

Abstract

In this study, a systematic analysis of the effect of three biomass pyrolysis oxygenates, viz., acetic acid, cyclopentanone and furfural, on the hydrodeoxygenation (HDO) of guaiacol is performed. Bifunctional Pt/HY catalysts with different Si/Al ratios were screened for the HDO of guaiacol. Guaiacol conversion and the cyclohexane yield increased with the concentration of acid sites in the zeolites. The presence of acetic acid and cyclopentanone did not affect the guaiacol conversion and the product selectivity, while guaiacol conversion decreased significantly in the presence of furfural. The effects of temperature, reaction time, and the guaiacol-furfural molar ratio on the HDO of guaiacol were studied. The time evolution of products showed that the furan ring opening influences the conversion of guaiacol. Quantum chemical density functional theory calculations using individual and binary model compounds revealed the decrease in adsorption energy of guaiacol over Pt (1 1 1) in the presence of furfural.

Keywords

HPC MKM