EFFICIENCY OF SUPPORTED PLATINUM CATALYSTS FOR THE DESTRUCTIVE OXIDATION OF ODOROUS COMPOUNDS IN AIR

The efficiency of catalysts for the destructive oxidation of malodorous compounds in air was investigated, using commercial platinum-honeycomb catalysts, promoted platinum metals on crimped ribbon and a laboratory-made catalyst, 0.3 % Pt on alumina spheres. With dimethyl sulphide (4-24 vpm) and n-butanal (15-100 vpm) as test compounds, removal efficiency was studied as a function of temperature, inlet concentration, space velocity, bed depth and catalyst structure. The interrelationship of temperature and space velocity was studied showing that although operating temperature for near complete removal of dimethyl sulphide can be less at lower space velocity, gradual catalyst deactivation determines the lowest useful temperature. At sufficiently high temperature, the removal efficiency eventually becomes limited by mass transfer and the effect of varying bed depth and catalyst support geometry on efficiency is discussed in terms of previously recommended transport property correlations. Field tests were conducted on the complex gas mixtures emitted from a hot-rendering process, operating the catalysts in a transportable reactor under the best conditions suggested by laboratory studies on single odorants; high odour removal efficiencies were demonstrated using both Chromatographic and sensory measurements. Further measurements on full-scale catalytic afterburners confirmed the efficiencies observed in laboratory and field tests. © 1979.