Advanced Short Contact Time Reactors for Catalytic Processes


CounterDowner™ is a gas-solid reactor in which the catalyst falls while the gas rises. This counter-current contact raises solids holdup and breaks particle clusters, which gives a more uniform contact time than conventional risers and co-current downers [211, 181] [patent 04, 08, 09]. The platform has been developed from laboratory rigs to scaled-up units, supported by computational and experimental design tools.

  • Hydrodynamics, solids flux, and residence-time control [211, 184, 181, 209]
  • Coupling with a riser and regenerator for continuous operation [184] [patent 03]
  • Application to direct crude-to-chemicals cracking [206, 177, 162, 104] [patent 05, 06, 12]
  • Multifunctional fluidized-bed concepts for process intensification [171] [patent 18]

Related People

Mengmeng Cui
Muhammed Ikbal Arikan
Talal Aldugman

Related Publications

Increasing solid holdup and de-clustering in downer reactors by counter-current operation
Fuel Year: 2027 DOI:https://doi.org/10.1016/j.fuel.2026.141109
Authors: Aldugman, Cui, Aldossary, Raja, Aguirre-Pablo, Alfilfil, Almajnouni, Gascon, Thoroddsen, Castaño
  • C2C
  • CRE
Operating Ranges of Coupled–Decoupled Counter-current Downer and Riser Reactors
ACS Eng. Au Year: 2025 DOI:https://doi.org/10.1021/acsengineeringau.4c00041
Authors: Cui, Alfilfil, Morales-Osorio, Almajnouni, Gascon, Castaño
  • C2C
  • FCC
  • CRE
  • MKM
Comparative analysis of counter-current and co-current downer reactors using particle image velocimetry and computational particle-fluid dynamics
Chem. Eng. J. Adv. Year: 2025 DOI:https://doi.org/10.1016/j.ceja.2024.100687
Authors: Aldugman, Cui, Alzailaie, Alhareth, Langley, Alfilfil, Almajnouni, Gascon, Thoroddsen, Castaño
  • C2C
  • FCC
  • MKM
  • CRE