Deactivation of SCR Catalysts by Exposure to Aerosol Particles of Potassium and Zinc Salts

Abstract

Generated aerosol particle deposition has been applied in laboratory scale to induce deactivation of commercial Selective Catalytic Reduction (SCR) catalysts of V 2 O 5 -WO 3 /TiO 2 monolithic type. The monolithic catalyst has been exposed to the generated submicrometer particle of inorganic salts, KCl, K 2 SO 4 , and ZnCl 2 at 200• C in a tubular reactor. The generated particles have been deposited on the catalytic surfaces by utilization of an electrostatic field. Physical characterization of the generated aerosol particles were conducted by Scanning Mobility Particle Sizer (SMPS) and Electric Low Pressure Impactor (ELPI) with and without catalyst in order to investigate the magnitude of the particle deposition. Particle charge distribution was also evaluated with a Tandem Differential Mobility Analyser (TDMA) set up.SCR is the most common method to commercially reduce NOx emissions from combustion processes. Catalyst lifetime is important for process economics and extending catalyst life can allow future strengthened emission legislation and diminished NOx emissions.Verification of particle deposition has been conducted through comparison with catalyst samples exposed to commercial biomass combustion condition.The reactivity of both fresh and exposed catalyst samples as well as commercially used samples was examined in SCR reaction and the methods of deposition as well as the influence of the different salts on catalytic performance have been explored. Catalyst samples have been evaluated with Scanning Electron Microscopy (SEM) with respect to surface morphology of the catalyst material. The laboratory deactivated catalyst samples showed resemblance with the commercially exposed catalyst sample with respect to salts concentration and deposition of the salts particles. The obtained influence on catalyst activity was comparable with commercially obtained catalyst activity reductions at comparable potassium concentration levels.

Poisoning Effects of Phosphorus, Potassium and Lead on V2O5-WO3/TiO2 Catalysts for Selective Catalytic Reduction with NH3

“…Though V 2 O 5 -WO 3 /TiO 2 catalysts show excellent activity in NH 3 -SCR process, many compounds including alkali/alkali earth metal elements, Pb, Zn, P and As are found in exhaust flue gas streams, which can lead to the deactivation of SCR catalysts in their lifetime. The deactivation mechanism of single element was studied in the past decades [1,[7][8][9][10][11][12][13]. Recently, the combined effects of different elements in the flue gas aroused the attention of scholars.…”

Deactivation of Co-Based Fischer–Tropsch Catalyst by Aerosol Deposition of Potassium Salts

“…Deactivating the Co catalysts by one potassium salt at a time helps obtain a detailed understanding of the deactivation mechanisms for that salt, while in an actual BTL plant, the catalyst will be exposed to all of the emitted deactivating species at once. 21 The method used here, to poison the catalyst by aerosol deposition, will hopefully improve the understanding of how the alkali (potassium specifically) influences a Co-based F-T catalyst and provide a more realistic representation of the in situ poisoning. The knowledge obtained can be useful in designing future BTL plants, and the methodology can be expanded to represent more complex mixtures.…”

Online Characterization of Syngas Particulates Using Aerosol Mass Spectrometry in Entrained-Flow Biomass Gasification

“…the turbine blades in gas turbines. Particles can also block or create channeling in catalytic beds and thereby deactivate the catalyst bed Larsson et al 2007). In addition to the problems described above, tars and soot also represent losses in the mass and energy balances.…”