Related Experiment Video
Updated: Aug 6, 2026

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction
Published on: August 31, 2018
Experimental and Numerical Study of Catalyst Temperature in Passive Autocatalytic Recombiner at Elevated Hydrogen
Alexander A Malakhov1, Maria H du Toit2, Alexander V Avdeenkov1,3
1DST Hydrogen Infrastructure Centre of Competence (HySA Infrastructure), Faculty of Engineering, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa.
Abstract:
This study investigates hydrogen catalytic recombination in a passive autocatalytic recombiner (PAR) at elevated hydrogen concentrations of 6-8 vol % in air. A combined experimental and numerical approach was used to test and characterize a cylindrical-type PAR catalyst for thermal response, conversion efficiency, and ignition threshold. Catalyst temperature and hydrogen concentration were studied in a small-scale facility, called the recombiner section testing station (RSTS), and compared with computational fluid dynamics (CFD) simulations. The model was developed and validated against experimental data in STAR-CCM+ software and incorporated the detailed heterogeneous and homogeneous reaction mechanisms from CHEMKIN kinetics simulation software. Experimental results showed a stable catalyst surface temperature with a maximum of 370-440 °C and hydrogen conversion efficiencies of ∼70%. Verification of turbulence models (k-ε and k-ω families) demonstrated a notable influence on temperature and species distribution, while neglecting thermal radiation led to overprediction of temperatures. The proposed CFD model demonstrated prediction with a deviation of 5% for catalyst temperature and 15% for hydrogen conversion. The model enabled evaluation of the ignition threshold by comparing the hydrogen reaction rate on the catalyst surface and in the gas phase. The onset of gas-phase hydrogen combustion was numerically calculated at 6 vol % of inlet hydrogen, indicating the lower ignition threshold for the cylindrical-type PAR catalyst configuration. The findings confirm that catalysts ensure safe and effective operation under high hydrogen concentrations and provide validated modeling guidance for hydrogen safety studies.
More Related Videos
10:19Synthesis and Testing of Supported Pt-Cu Solid Solution Nanoparticle Catalysts for Propane Dehydrogenation
Published on: July 18, 2017
12:08Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes
Published on: June 24, 2022
Related Concept Videos
Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Catalysis
Catalysis
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Heterogeneous Catalysis
Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation