Poisoning Effects of HCl on MO_x‐WO₃/TiO₂ (M=Mn, Ce and V) Catalysts for Selective Catalytic Reduction of NO_x by NH₃

Abstract

Selective catalytic reduction of NO x by ammonia (NH 3 -SCR) was affected by HCl, which was widely present in industrial flue gas. In this study, the SCR performances over MO x -WO 3 /TiO 2 (MW/Ti, M = Mn, Ce and V) catalysts after HCl treatment were investigated. It was found that HCl poisoning showed inhibition and promotion in NO x conversion over MnW/Ti and CeW/Ti catalysts, respectively. While the SCR activity over VW/Ti catalyst was hardly affected by HCl. Over MnW/Ti catalyst, the rupture of the MnÀ O bond by the strong MnÀ Cl binding induced the formation of amorphous MnCl 2 species. This Cl-containing species with Mn in a low oxidation state exhibited poorer redox ability and NO activation, resulting in a decrease in lowtemperature SCR activity. However, instead of directly affecting the CeO x and VO x sites, gaseous HCl reacted with NH 3 to form NH 4 Cl species on the surface of CeW/Ti and VW/Ti catalysts. As a result, the SCR activity of VW/Ti catalyst was scarcely influenced by HCl, taking the unchanged redox ability and NH 3 adsorption. With a further accumulation of NH 4 Cl on CeW/Ti catalyst, the NO x conversion at low temperature was evidently enhanced due to the promotion in NO-to-NO 2 conversion (Fast-SCR).

Infrared Spectrum and Principal Component Analysis of Heavy Tar Cut by Different Fractions from Tar-Rich Coal

“…By considering the infrared spectrum of HCT as a reference, it was determined that when the number of main components was set to 2, the cumulative amount reached 96.93%. This indicates that there were two principal peaks in the infrared spectrum that could be used for analysis . Based on this information, the peaks in PC1 and PC2 were identified and extracted.…”

“…This indicates that there were two principal peaks in the infrared spectrum that could be used for analysis. 24 Based on this information, the peaks in PC1 and PC2 were identified and extracted. PC1 exhibited strong peak signals near 749 and 687 cm −1 .…”