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The Desulfation Characteristics of Lean NOx Traps
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 4, 2002 by SAE International in United States
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This paper summarizes results from a large study on the desulfation characteristics of lean NOx traps. Degreened and thermally aged NOx trap formulations were poisoned with SO2 multiple times in a flow reactor. The effect of desulfation time and temperature on the recovery of NOx trapping efficiency was evaluated after the poisonings. The relative effectiveness of the reducing agents (CO and H2) used during the desulfation was evaluated for one of the formulations.
The results indicate that the high temperatures required for desulfation (e.g., 700°C and above) result in thermal degradation of NOx traps that had been degreened at a lower temperature (e.g., 600°C), and therefore desulfation studies should be performed with traps that have already been exposed to the desulfation temperatures or higher prior to the poisoning. NOx trap formulations can differ in their desulfation characteristics, as two of the formulations studied could be desulfated effectively at 725°C, whereas the third formulation was more difficult to desulfate and required a desulfation temperature near 750°C. The results indicate that hydrogen is the more effective desulfation agent, as higher levels of H2 in the feedgas or additional H2 produced by the water-gas-shift reaction resulted in improved NOx trapping efficiency following the desulfation.
CitationTheis, J., Li, J., Ura, J., and Hurley, R., "The Desulfation Characteristics of Lean NOx Traps," SAE Technical Paper 2002-01-0733, 2002, https://doi.org/10.4271/2002-01-0733.
- Miyoshi Naoto, Matsumoto S., Katoh K., Tanaka, T. Harada J., Takahashi N., Yokota K., Sgiura M., and Kasahara K., “Development of New Concept Three-Way Catalyst for Automotive Lean-Burn Engines”, SAE Paper no. 950809.
- Brogan M., Clark A., and Brisley R., “Recent Progress in NOx Trap Technology”, SAE Paper no. 980933.
- Gluck K.H., Gobel U., Hahn H., Hohne J., Krebs R., Kreuzer T., and Pott E., “Cleaning the Exhaust Gas of Volkswagen FSI Engines”, MTZ Motortechnische Zeitschrift 61 (2000) 6.
- Erkfeldt S., Larsson M., Hedblom H., and Skoglundh M., “Sulphur Poisoning and Regeneration of NOx Trap Catalyst for Direct Injected Gasoline Engines”, SAE Paper no. 1999-01-3504.
- Erkfeldt S., Skoglundh M., and Larsson M., “Poisoning and Regeneration of NOx adsorbing catalyst for automotive applications”, Catalyst Deactivation, Brugge, Belgium, October 11-13, 1999.
- Matsumoto S., Ikeda Y., Suzuki H., Ogai M., and Miyoshi N., “NOx storage-reduction catalyst for automotive exhaust with improved tolerance against sulfur poisoning”, Applied Catalysis B: Envinmental 25 (2000) pp 115-124.
- Hepburn J., Thanasiu E., Dobson D., and Watkins W., “Experimental and Modeling Investigations of NOx Trap Performance”, SAE Paper no. 962051.
- Dou D. and Bailey O., “Investigation of NOx Adsorber Catalyst Deactivation”, SAE Paper no. 982594.
- Strehlau W., Leyrer J., Lox E., Kreuzer T., Hori M., and Hoffmann M., “New Developments in Lean NOx Catalysis for Gasoline Fueled Passenger Cars in Europe”, SAE Paper no. 962047.
- Li J., Theis J., Chun W., Goralski C., Kudla R., Ura J., Watkins W., Chattha M., and Chattha R., “Sulfur Poisoning and Desulfation of the Lean NOx Trap”, SAE Paper no. 2001-01-2503, August, 2001.
- Hodjati S., Semelle F., Moral N., Bert C., and Rigaud, M. “Impact of Sulphur on the NOx Trap Catalyst Activity- Poisoning and Regeneration Behaviour”, SAE Paper no. 2000-01-1874.
- Mahzoul H., Limousy L., Brilhac J., and Gilot P., “Experimental study of SO2 adsorption on barium-based NOx adsorbers”, Journal of Analytical and Applied Pyrolysis 56 (2000) pp. 179-193.
- Miyoshi N. and Mastumoto S., “NOx Storage-reduction Catalyst (NSR Catalyst) for Automotive Engines: Sulfur Poisoning Mechanism and Improvement of Catalyst Performance”, Science and Technology in Catalysis, 1998, pp. 245-250.
- Theis J. and Balland J., “A NOx Adsorber Diagnostic System for Direct-Injection Gasoline Applications”, Global Powertrain Congress, 1999, pp. 99-110.
- Asik J., Meyer G., and Dobson D., “Lean NOx Trap Desulfation Through Rapid Air Fuel Modulation”, SAE Paper no. 2000-01-1200, February, 2000.
- Hepburn J., Dobson D., Hubbard C., and Otto K., “The Pulse Flame Combustor Revisited”, SAE Paper no. 962118.
- Obert E., Internal Combustion Engines and Air Pollution, Intext Educational Publishers, New York, 1973, p 731.