CATALYTIC DECOMPOSITION OF OZONE IN THE PRESENCE OF WATER-VAPOR

The catalytic decomposition of ozone in the presence of water vapor at the relative humidity (RH) of about 90 % was investigated by using a tubular fixed-bed reactor. The performance tests and reaction kinetic studies were conducted for catalyst, i.e., Pt/gamma-Al2O3 (symbolized as Dash-220). The experiments were carried out at various constant rea ction temperatures (298 similar to 323 K) and space velocities (24,000 similar to 44,000 hr(-1)). About 75 % decomposition efficiencies of o zone with inlet concentration of about 0.17 mol/m(3) was achieved at c atalyst contact time of 015 sec (space velocity of 24,000 hr(-1)), rea ction temperature of 323 K and RH of about 90 % for the Dash-220 catal yst. However, about 97 % decomposition efficiencies of ozone without t he presence of water vapor at the same reaction conditions. The result s indicated that the Dash-220 catalyst with the presence of water vapo r gave lower performance of ozone decomposition than without the prese nce of water vapor can be achieved at the same reaction conditions. Fo r the reaction kinetics, it was found that the pseudo-first-order chem ical reaction rate equation was appropriate for the catalytic decompos ition of ozone in the presence of water vapor investigated in this stu dy. The apparent activation energies for the decomposition reaction of ozone using the Dash-220 catalyst in the presence of water vapor at R H of 90 % is 19.32 kJ mol(-1). The corresponding pre-exponential facto r is 0.0041 mol/(s g-catalyst (mol/m(3))).