(30c) Removal of Aircraft Cabin Ozone by Microfibrous Material at Micro Second Contact Time

Microfibrous Entrapped Catalyst (MFEC) manufactured from 8 μm diameter nickel fibers were engineered into pleated heterogeneous catalytic reactors to improve removal performance from traditional packed bed and monolith reactors, since microfibrous materials can entrap small particles (150-200 μm) which significantly improves inter phase and intra particle mass transfer. These special reactors were targeted at ozone, which was widely recognized as No.1 aircraft cabin air pollutant. In this project, MFEC reactors were investigated under aircraft bleed air conditions of high temperature (150-200C) and high face velocity (10-30 m/s) for different catalysts (Pd, Ag, Mn). Catalysts were impregnated on entrapped particles (e.g. γ-Al2O3) using incipient wetness method. Ozone test concentration was set at a high-demanding 1.5 ppmv. Results showed that even if much less amount of metal catalysts were entrapped in microfibrous materials, a high level of ozone decomposition was accomplished. Compared with conventional aircraft filters, this can be a huge advantage in terms of material cost and labor. Reaction kinetics analyses were compared for different catalysts. Also catalyst aging tests were carried according to the frequency of commercial aircraft ozone reactor replacement, which evaluated long-term performance for actual MFEC reactor usage. In addition, pressure drop improvement by pleating MFEC was also evaluated with comparison of traditional low pressure drop monolith reactors. CFD model has also been established for pressure prediction and comparison. It showed that pleated structure enable MFEC to avoid higher pressure drop and eliminate the problem of direct channeling caused monolith.