(621dv) Reactor Simulation of Photocatalytic Carbon Dioxide Conversion By Saturated Steam over TiO2

Reactor Simulation of Photocatalytic Carbon Dioxide Conversion by Saturated Steam over TiO₂

Mohammad E. Raihan and Tracy J Benson

Photocatalytic conversion of flue gases containing carbon dioxide and steam can be a sustainable method for decreasing CO₂ emissions from large point sources (i.e. steam methane reforming and electric power generators). Our laboratory has developed an annual photocatalytic reactor with a highly efficient catalyst loading mechanism that maximizes the use of UV light and minimized diffusion resistances. Subsequently, we have developed a comprehensive model that includes the geometry, radiation absorption to predict the fraction of useful protons, the momentum balance equations, and the reaction kinetics equations. This model is useful for scale up of photocatalytic reactors and is robust to incorporate advances in catalyst design (i.e. lower band-gap energies or multi-functionality).

To validate the model, experiments have been conducted to determine conversion and kinetics of the photocatalysis of carbon dioxide and saturated steam over TiO₂ (Degussa P25) under UV irradiation, where many products such as CO, H₂, CH_4, C₂H₆ have been found. The catalyst powders are supported on treated fiberglass gauze to enhance the photon collecting efficiency and catalyst distribution within the reactor.  The complete reactor details and modeling with be demonstrated in the presentation.