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

Effect of Space Velocity on the Hydrocracking of Light Cycle Oil over a Pt-Pd/HY Zeolite Catalyst

by Gutierrez, Arandes, Castaño, Olazar, Barona, Bilbao
Fuel Process. Technol. Year: 2012

Abstract

The effect of space velocity (WHSV) has been studied in the single-step hydrocracking of the LCO (Light Cycle Oil) obtained as byproduct in catalytic cracking (FCC) units, over a bifunctional catalyst of Pt–Pd supported on a high acidity HY zeolite. Accordingly, the hydrocracking and hydrodesulphurization conversions and yields of product fractions (medium distillates, naphtha, LPG and dry gas) have been determined. The reaction conditions have been 350 °C, 45 bar, H2/LCO molar ratio of 10. The catalyst reaches a pseudoestable state subsequent to a rapid initial deactivation and maintains a significant activity in this state for the production of medium distillates and naphtha. Studies have been carried on the composition of these streams and their interest for adding to the pools of diesel and gasoline. The results are encouraging for the upgrading of LCO by its hydrocracking over noble metal catalysts, given that they are of high activity.

Keywords

HPC MKM W2C