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 Covers

Related Publications

Comprehensive Approach for Designing Different Configurations of Isothermal Reactors with Fast Catalyst Deactivation

by Cordero-Lanzac, Aguayo, Gayubo, Castaño, Bilbao
Chem. Eng. J. Year: 2020

Abstract

A methodology for simulating the performance of different reactor configurations for processes with complex reaction networks and fast catalyst deactivation has been proposed. These reaction configurations are: packed bed, moving bed and fluidized bed reactors with and without catalyst circulation. From kinetic parameters collected in a packed bed reactor and a rigorous consideration of the activity, modifications in the convection-dispersion-reaction equation have led to the prediction of the catalyst performance in each reactor configuration. The circulating fluidized bed reactor has been simulated with an original model of parallel compartments, which allows for determining its performance in the steady state from the evolution of the transitory period. The methodology has been used for simulating the dynamics of SAPO-34 fast deactivation during the methanol-to-olefins (MTO) process. For each reactor configuration, concentration profiles and their evolution with time have been simulated, thus predicting the effect of reaction conditions and water content (formed and/or co-fed) on the activity profile or the activity distribution function (in the case of circulating fluidized bed reactor). The olefin yield and distribution have also been compared for each reactor configuration.

Keywords

O2H FCC CRE MKM