(27g) Microfibrous Entrapped Catalyst for Cleaning Air: VOC Oxidation At Ultra-Short Contact Time

Purification of indoor and outdoor air quality is essential to ensure safety and comfortable environment. Among various molecular contaminants, volatile organic compounds (VOCs) are one of the major challenges that require eliminating from air. Hence, catalytic removal of VOCs (using catalytic reactor) is of utmost important. A unique class of microstructured heterogeneous contacting system called microfibrous entrapped catalyst (MFEC), was prepared by entrapping small catalyst support particles (150–250 μm ɣ-Al₂O₃) into a sinter-locked metal microfibers (i.e. 8 μm Ni fibers), which is uniform in structure. In this work, catalytic oxidation of VOC (i.e. n-hexane as a model compound and challenge concentration~10 ppmv) was conducted at high face velocities (ca. 10 to 30 m/s) by using 1.5% Pd/ɣ-Al₂O₃ as catalyst in a pleated MFEC configuration (Number of pleat 4) for a certain range of temperatures (100-200°C). These high face velocities in thin flexible sheets of MFEC, resulted intrabed/intralayer residence times from 65 to 230 μsec. Significant reduction in n-hexane concentration was observed even for high face velocity (40% reduction at 30 m/s and 200°C), and the result showed that the surface reaction rate prevailed the diffusion rate in overall reaction mechanism. Detailed reaction kinetics involving activation energy (~47 kJ/mol), axial and radial dispersion, fluid-solid mass transfer rates have also been observed.