Formation and reaction of ammonium sulfate salts on V2O5/AC catalyst during selective catalytic reduction of nitric oxide by ammonia at low temperatures

Abstract The formation rate and reaction rate of ammonium sulfate salts on V 2 O 5 /AC catalyst during selective catalytic reduction (SCR) of NO with NH 3 at low temperatures were studied using elemental analysis, transient response, and TPR methods. In the presence of SO 2 and H 2 O, ammonium sulfate salts deposit on the surface of the V 2 O 5 /AC catalyst, block the pores of the catalyst, and cause catalyst deactivation. Moreover, the deactivation rate increases with increasing H 2 O content in the flue gas. The deposition rate of the ammonium sulfate salts is governed by the rate difference between its formation and reaction with NO. In the presence of H 2 O, the formation rate of the ammonium sulfate salts is higher than that in the absence of H 2 O, and the reaction rate between the formed ammonium sulfate salts and NO is lower than that in the absence of H 2 O. SO 2 does not affect the reaction rate of the ammonium sulfate salts with NO. FT-IR and XRD analysis show that the ammonium sulfate salts formed in the presence of SO 2 and H 2 O on the catalyst surface at 250 °C is mainly (NH 4 ) 3 H(SO 4 ) 2 .

[1]  R. T. Yang,et al.  The promoting role of rare earth oxides on Fe-exchanged TiO2-pillared clay for selective catalytic reduction of nitric oxide by ammonia , 2000 .

[2]  W. S. Kijlstra,et al.  Deactivation by SO2 of MnOx/Al2O3 catalysts used for the selective catalytic reduction of NO with NH3 at low temperatures , 1998 .

[3]  K. Tarama,et al.  Spectroscopic Studies of Catalysis by Vanadium Pentoxide , 1968 .

[4]  N. Topsoe,et al.  Mechanism of the Selective Catalytic Reduction of Nitric Oxide by Ammonia Elucidated by in Situ On-Line Fourier Transform Infrared Spectroscopy , 1994, Science.

[5]  Ken Nobe,et al.  Reduction of NO with NH3 on Al2O3− and TiO2-supported metal oxide catalysts , 1986 .

[6]  G. Deo,et al.  Reactivity of V2O5Catalysts for the Selective Catalytic Reduction of NO by NH3: Influence of Vanadia Loading, H2O, and SO2 , 1996 .

[7]  Young Gul Kim,et al.  Deactivation of copper-ion-exchanged hydrogen-mordenite-type zeolite catalyst by SO2 for no reduction by NH3 , 1992 .

[8]  J. Spivey,et al.  Low-temperature NOx removal for flue gas cleanup , 1996 .

[9]  R. T. Yang,et al.  Selective Catalytic Reduction of NO with NH3 on SO−24/TiO2 Superacid Catalyst , 1993 .

[10]  R. T. Yang,et al.  Selective Catalytic Reduction of Nitrogen Oxides by Ammonia over Fe3+-Exchanged TiO2-Pillared Clay Catalysts , 1999 .

[11]  P. Forzatti.  Environmental catalysis for stationary applications , 2000 .

[12]  Zhenyu Liu,et al.  Decomposition and Reactivity of NH4HSO4 on V2O5/AC Catalysts Used for NO Reduction with Ammonia , 2000 .

[13]  Zhenyu Liu,et al.  Promoting Effect of SO2 on Activated Carbon-Supported Vanadia Catalyst for NO Reduction by NH3 at Low Temperatures , 1999 .

[14]  R. T. Yang,et al.  Characterization of Fe-ZSM-5 Catalyst for Selective Catalytic Reduction of Nitric Oxide by Ammonia , 2000 .

[15]  J. Dumesic,et al.  Influence of water on the reactivity of vanadia/titania for catalytic reduction of NOx , 1992 .

[16]  Zhenyu Liu,et al.  NO reduction with NH3 over an activated carbon-supported copper oxide catalysts at low temperatures , 2000 .

[17]  D. M. Hausen,et al.  Infrared Spectra-Structure Correlation Study of Vanadium-Oxygen Compounds. , 1963 .

[18]  G. Marbán,et al.  Low temperature selective catalytic reduction of NO over modified activated carbon fibres , 2000 .