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

One-step conversion of crude oil to light olefins using a multi-zone reactor

by Alabdullah, Rodriguez Gomez, Shoinkhorova, Dikhtiarenko, Chowdhury, Hita, Vittenet, Sarathy, Castaño, Bendjeriou-Sedjarari, Abou-Hamad, Zhang, Ali, Morales-Osorio, Xu, Gascon
Nat. Catal. Year: 2021

Abstract

With the demand for gasoline and diesel expected to decline in the near future, crude-to-chemicals technologies have the potential to become the most important processes in the petrochemical industry. This trend has triggered intense research to maximize the production of light olefins and aromatics at the expense of fuels, which calls for disruptive processes able to transform crude oil to chemicals in an efficient and environmentally friendly way. Here we propose a catalytic reactor concept consisting of a multi-zone fluidized bed that is able to perform several refining steps in a single reactor vessel. This configuration allows for in situ catalyst stripping and regeneration, while the incorporation of silicon carbide in the catalyst confers it with improved physical, mechanical and heat-transport properties. As a result, this reactor–catalyst combination has shown stable conversion of untreated Arabian Light crude into light olefins with yields per pass of over 30 wt% with a minimum production of dry gas.

Keywords

C2C HCE MKM CRE