Fast Estimation of Reaction Rates in Spherical and Non-Spherical Porous Catalysts

John Wakefield, Aaron Lattanzi, M. Pecha, Peter Ciesielski, Jesse Capecelatro

Research output: Contribution to journalArticlepeer-review

1 Scopus Citations


We present a methodology for modeling multi-step reaction rates in porous catalyst particles for use in CFD–DEM and two fluid models. Single-step effectiveness factors based on a Thiele modulus, while useful, cannot accurately capture the cascading reaction systems common in high temperature vapor-phase chemical reactors like fluidized catalytic cracking units and catalytic biomass fast pyrolysis systems. Instead, multi-step effectiveness vectors derived from steady-state solutions to the governing reaction–diffusion equations are needed. Solutions for various catalyst shapes are presented, including spheres, cylinders, and prisms. Computational challenges inherent in repeated evaluation of reaction rates with diffusion limitations are discussed, and an efficient implementation based on pre-computed lookup tables is proposed and demonstrated on a simulation of a fluidized bed reactor. Open-source code is provided for the compilation of reaction rate tables for use in ODE, DEM, and two-fluid models.

Original languageAmerican English
Article number139637
Number of pages12
JournalChemical Engineering Journal
Issue numberPart 1
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

NREL Publication Number

  • NREL/JA-2800-83458


  • Catalysis
  • Effectiveness factor
  • Intraparticle diffusion
  • Lumped kinetics
  • Non-spherical


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