Comparison of Packed Beds, Washcoated Monoliths, and Microfibrous Entrapped Catalysts for Ozone Decomposition at High Volumetric Flow Rates in Pressurized Systems

Abstract

Weight- and volume-sensitive systems such as aircraft require restrictive ducting, which leads to high face velocities (10–40 m/s) in reactive structures. A head-to-head comparison was conducted experimentally among packed beds (estimated data), monoliths, and microfibrous entrapped catalysts (MFECs) during ozone decomposition to investigate the effects of system pressure on the effective reaction rate, gas–solid mass-transfer rate, and heterogeneous contacting efficiency (HCE, the ratio of the logarithmic ozone removal to the pressure drop across the reactor). For the same mass flow rate, higher-pressure systems (2–3 atm) operate at lower face velocities than atmospheric-pressure systems. These higher system pressures result in increased residence times and reaction rates; therefore, HCE is enhanced. In addition, the HCE for the MFEC was more than twice that of the packed bed or monolith at equivalent system pressures because of the higher gas–solid mass-transfer rates and reduced pressure drops of the MFEC.