Yaxin Su

Title : SCR of NO with C3H6 over iron modified Ag/Al2O3 catalysts supported on honeycomb ceramic

Abstract:

Ag supported on Al2O3 catalyst showed good activity in the SCR of NO by HC agents. The resistance of Ag/Al2O3 catalysts to H2O and SO2 in the flue gas is a problem. Mg was used to modify the Ag/Al2O3 catalyst and the resistance of Ag/Al2O to SO2 can improved, but H2O had a great influence on the reduction of NO by Ag/Mg/Al2O3, e.g., at 350?C, the addition of 9% H2O reduced the conversion of NO by 40% and the conversion of reducing agent C3H6 by 10% respectively. The resistance of Ag based catalysts to SO2 and H2O remains to be further investigated for HC-SCR of NO. 
In this presentation, Ag/Al2O3 catalysts supported on honeycomb ceramic were prepared by sol-gel and impregnation methods and modified with Fe to promote the catalytic performance for SCR of NO with C3H6 and to improve the resistance to SO2 and H2O. The catalytic performance to reduce NO with C3H6 was evaluated in a one-dimensional electrically heated temperature programmed ceramic tubular reactor in simulated flue gas atmosphere at 200?700°C. The results show that the NO reduction efficiency on 7.2Fe/1.9Ag/20Al2O3/CM with C3H6 is more than 90% and reaches about 100% at the temperatures of 500 ?C and 550 ?C respectively. Iron can effectively improve the ability of Ag/20 Al2O3/CM catalysts to resist SO2 and H2O in flue gas. When SO2 and H2O are 0.02% and 8% in the flue gas, the NO reduction efficiency is almost not influenced on 7.2Fe/1.9Ag/20 Al2O3/CM at 500 ?C. The 90% NO reduction efficiency is maintained during 6 h without decrease. However, the catalytic activity of 2Ag/20 Al2O3/CM without iron modification is strongly influenced by SO2 and H2O in the flue gas. The NO reduction efficiency on Ag/20Al2O3/CM decreases rapidly from about 70% to 46% and 25% respectively, when the SO2 and H2O are 0.02% and 8% in the flue gas. The results of XRD and SEM of the catalyst show that AgFeO2 and Fe3+ are formed in the 7.2Fe/1.9Ag/20 Al2O3/CM catalyst after the modification by iron, and the surface of the catalyst become loose and porous, forming Fe3O4-based needle-like and flaky crystals. H2-TPR results show that 7.2Fe/1.9Ag/20 Al2O3/CM has better reduction properties than Ag/20Al2O3/CM in the wider temperature range. Pyridine adsorption Infrared Spectroscopy (Py-FTIR) experimental results show that Fe increases the Lewis acid sites in the catalyst surface.

Biography:

Yaxin Su received his BS of Exploring Engineering from China University of Geosciences in 1994, MS of Mechanical Engineering with a focus on heat transfer from National Huaqiao University, China, in 1997 and PhD of Power Engineering and Thermophysics with a focus on combustion from Zhejiang University, China, in 2000. He worked in the Department of Chemical Engineering, University of Mississippi, USA as a visiting professor during 2006-2007.  He is currently a professor in the School of Environmental Science and Engineering, Donghua University, China. He was the Chair of the Department of Built Environment and Energy Engineering during 2006-2009 and also was the course director and coordinator of the joint MS program of Sustainable Energy Technology between Donghua University and the University of Nottingham, UK during 2006-2009. Dr Su has been involved in heat transfer, gas-solid suspension flow and separation, thermo-chemical conversion of solid fuels, such as pyrolysis and combustion of coal, biomass and waste sludge, pollutant emission control, such as NOx reduction, CO2 capture, etc.  He has published 3 academic books and 2 textbooks, more than 100 journal articles and 50 international conference papers.