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

Stability of an Acid Activated Carbon Based Bifunctional Catalyst for the Raw Bio-Oil Hydrodeoxygenation

by Cordero-Lanzac, Palos, Arandes, Castaño, Rodriguez-Mirasol, Cordero, Bilbao
Appl. Catal. B: Environ. Year: 2017

Abstract

The performance (activity, selectivity and stability) of a Pt-Pd catalyst supported on a phosphorus-containing activated carbon (ACP) has been studied in the hydrodeoxygenation (HDO) of raw bio-oil, and compared with another bifunctional catalyst prepared with a FCC (Fluid Catalytic Cracking) catalyst as acid support. Experiments have been carried out in a fixed bed reactor under the following conditions: 400–450 °C; 65 bar; space time, 0.18 gcat h g−1bio-oil; H2:bio-oil ratio, 20 cm3H2 (STP) cm−3bio-oil; time on stream, 0–10 h. The catalyst reaches a pseudo-steady state at 450 °C after 6 h of time on stream, preserving a constant activity as a consequence of the simultaneous formation and hydrocracking of the deposited coke. In these conditions, the yield of C5+ hydrocarbons is 20 wt%. This organic liquid fraction mainly contains aromatics, and thus, it may require an additional mild hydrocracking treatment for its valorization as fuel. On the other hand, the gas fraction obtained can be used directly as fuel, and the aqueous liquid fraction (with a high concentration of methanol, 58 wt%) is interesting as co-feedstock with methanol in a methanol to olefins (MTO) unit.

Keywords

HPC W2C MKM