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Study on the decomposition of trace benzene over V2O5–WO3/TiO2-based catalysts in simulated flue gas
Citation:
Lu, S., Q. Wang, W. R. Stevens, Chun Wai Lee, B. K. Gullett, AND Y. Zhao. Study on the decomposition of trace benzene over V2O5–WO3/TiO2-based catalysts in simulated flue gas. APPLIED CATALYSIS B: ENVIRONMENTAL. Elsevier Science Ltd, New York, NY, 147:322-329, (2014).
Impact/Purpose:
The aims of this study were to investigate the catalytic activity of the V2O5–WO3/TiO2-based honeycombed catalysts varied in composition ratio and supports (i.e., nano-scale and conventional TiO2) towards trace levels (1–10 ppm) of benzene under experimental conditions quite close to the operating conditions in industrial applications. The effects of numerous key parameters (operating temperature, initial concentration, space velocity, and flue gas components) will be discussed, providing an experimental basis for further research on catalytic destruction of PCDD/Fs in flue gas from actual incinerator plants.
Description:
Trace levels (1 and 10 ppm) of gaseous benzene were catalytically decomposed in a fixed-bed catalytic reactor with monolithic oxides of vanadium and tungsten supported on titanium oxide (V2O5–WO3/TiO2) catalysts under conditions simulating the cooling of waste incineration flue gas. On-line monitoring of trace benzene concentrations before and after the catalyst was achieved by means of Resonance Enhanced Multiphoton Ionization - Time of Flight Mass Spectrometry (REMPI-TOFMS). The effects of several parameters, including operating temperature, space velocity (SV) and initial benzene concentration, on catalytic oxidation of benzene over three types of honeycombed V2O5–WO3/TiO2 catalysts (VWNT, VWT1 and VWT2) were investigated. Experimental results indicate that further reduction of the benzene initial concentration from 10 to 1 ppm either enhances or decreases the catalytic removal efficiency depending on the adsorption capability as well as the oxidation ability of the catalyst tested. The catalyst activity for benzene oxidation not only relies on the active component content of the catalyst but also on the catalyst support species: catalyst with nano-sized TiO2 as the support (VWNT) provides higher catalytic activity than catalysts using conventional TiO2 as the support (VWT1 and VWT2). Results also indicate that, under this set of experimental conditions, no competition between NOx removal and benzene oxidation was observed. The Mars-Van Krevelen model was applied in this study to calculate the activation energies for benzene oxidation over the tested catalysts. The activation energies needed for benzene oxidation reaction over VWNT, VWT1 and VWT2 are calculated as 25.6 kJmol-1, 29.7 kJmol-1 and 30.6 kJmol-1, respectively.
