Kinetic analysis of TiO2-catalyzed heterogeneous photocatalytic oxidation of ethylene using computational fluid dynamics

• TiO2-catalyzed ethylene photooxidation was carried out with a non-ideal flow reactor.
• Kinetic parameters were determined using CFD analysis.
• A low Reynolds number-type k-ε turbulence model was adopted.
• Ethylene oxidation behavior was compared for two kinds of reactors.

Photocatalytic oxidation of ethylene was carried out over a TiO2 catalyst at 295 K using two types of non-ideal fixed-bed flow reactors: a rectangular reactor and a cylindrical reactor. Computational fluid dynamics (CFD) analysis using a low Reynolds number-type k-ε turbulence model was conducted to investigate the ethylene oxidation behavior in the reactors at various gas flow rates and ethylene concentrations in the inlet gas (ethylene concentration of 50–250 ppm and gas flow rate of 50–250 mL/min). In the rectangular reactor, steady-state activities were obtained for ethylene oxidation under all conditions. The rate of ethylene oxidation on the TiO2 surface was analyzed in terms of Langmuir–Hinshelwood (L–H) type kinetics. The kinetic parameters for the surface reactions obtained via CFD analysis fit well with the experimental data. The CFD analysis also revealed that the ethylene concentration distribution in the reactor depended on the gas residence time distribution. We also carried out CFD analysis for the cylindrical reactor and compared the ethylene oxidation behavior with that in the rectangular reactor.

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