Journal du génie chimique et de la technologie des procédés
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Computational Fluid Dynamics in Microreactors Analysis and Design: Application to Catalytic Oxidation of Volatile Organic Compounds

Odiba S, Olea M, Hodgson S, Adgar A and Russell PA

This paper deals with the design of a suitable microreactor for the catalytic oxidation of volatile organic compounds (VOCs). There are a number of ways to release VOCs into the atmosphere, typically during processing of natural gas and handling petroleum products. As VOCs are harmful to our health, there is increased scientific interest in developing technologies for their destruction. Catalytic oxidation is one of them. Microreactors have showed higher efficiency than the conventional ones, mainly due to their large surface area to volume ratio and excellent heat and mass transfer properties. The design of a microreactor can be explored based on simulation results obtained by using computational fluid dynamics (CFD) package of COMSOL Multiphysics. The first design step, based on cold flow simulation, was the selection of the most suitable microreactor geometry and configuration. Four different geometries had been proposed and simulated to evaluate the fluid behaviour in the microchannels. One of them, Type A2, allowed the most uniform flow distribution in all channels, as assessed through relative standard deviation calculations. The second design step involved the investigation of the VOCs catalytic oxidation, using propane as model molecule, occurring in the microreactor with the geometry/configuration previously found. The proposed microreactor consists of eleven parallel channels of square cross-section, with 0.5 × 10-3 m width, 0.5 × 10-3 m height and 0.1 m length. The catalytic microreactor was simulated for temperatures between 563 K and 663 K and inlet flow velocities from 0.01 to 1.00 m·s-1. The exit propane conversion increased rapidly with increasing temperature for a fixed inlet flow velocity. For a fixed temperature, the propane conversion increased as the inlet flow velocity decreased.