화학공학소재연구정보센터
Canadian Journal of Chemical Engineering, Vol.97, 1407-1417, 2019
Performance of Low-temperature SCR of NO with NH3 over MnOx/Ti-based catalysts
The effects of Mn loadings and precursors, catalyst preparation methods, incineration durations and temperatures, and the addition of Co and Ce on NO-reduction efficiency and selectivity (N2O formation) during the preparation of MnOx/Ti-based catalysts were studied by micropore-size analysis (XRD, XPS, SEM, and FTIR), while considering changeable parameters. Meanwhile, the performance of low-temperature SCR of NO with NH3 over the designed catalysts was tested under various gas hourly space velocities (GHSVs), NH3/NO molar ratios, and contents of NO, NH3, O-2, H2O, and SO2 in a lab-scale reactor. Overall, the Mn(0.3)Ce(0.1)/Ti catalyst, which had high NO-reduction efficiency and selectivity (low N2O formation), was recommended, with the following preparation methods: ultrasonic impregnation; manganese acetate precursor; and incineration at 500 degrees C. Appropriate textural properties (high surface area and small pore and crystallite sizes), well-dispersed amorphous manganese (rather than crystalline) on the anatase surface (rather than rutile), abundant active sites, and long residence time are essential for high NO-reduction efficiency. In practice, NO-reduction efficiency decreased with increasing GHSV and the NH3 and NO contents; however, it initially increased and then became saturated with an increasing NH3/NO molar ratio and O-2 content. Water deactivated the catalyst to a recoverable state, whereas SO2 resulted in unrecoverable deactivation.