The dynamics of the desulfation of a Ba-containing and a K-containing NOx storage catalyst have been investigated. When both catalysts were desulfated using a temperature ramp in exhaust that simulated gasoline exhaust with a 13:1 A/F, the maximum desulfation rate for the Ba-containing catalyst was seen at 620°C, while the maximum for the K-containing catalyst was at 760°C. This is consistent with the widely known fact that K2SO4 is more stable than BaSO4.The BaSO4 decomposed when either hydrogen or water was in the feed, but not when both were absent. The decomposition, therefore, requires hydrogen to be present and the water can provide sufficient hydrogen for the decomposition via the water-gas shift reaction. With either water or hydrogen in the uncycled feed, the primary sulfur compound formed from the decomposition was H2S for both the Ba and K-containing catalysts.Cycling the feed increased the amount of sulfur released as SO2 from the Ba-containing catalyst, but was not as effective in removing sulfur as continuous rich operation. Cycling the feed to the K-containing catalyst greatly reduced the desulfation of the catalyst without significantly increasing the sulfur release as SO2.Thermodynamic calculations of the desulfation reactions with CO or H2 are consistent with the experimental results. The sulfates (K2SO4, BaSO4, and Ce2(SO4)3) are far less stable in H2 than in CO and their decomposition to form H2S is clearly favored over their reactions with CO to form SO2. Among these sulfates, Ce2(SO4)3 is the least stable and is the only one that decomposes in the absence of hydrogen.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Desulafation Dynamics of NOx Storage Catalysts


    Weitere Titelangaben:

    Sae Technical Papers


    Beteiligte:
    Monroe, David R. (Autor:in) / Li, Wei (Autor:in)

    Kongress:

    SAE Powertrain & Fluid Systems Conference & Exhibition ; 2002



    Erscheinungsdatum :

    2002-10-21




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




    Desulfation dynamics of NOx storage catalysts

    Monroe,D.R. / Li,W. / General Motors Res.a.Dev.Labs.,US | Kraftfahrwesen | 2002


    Desulafation Dynamics of NO~x Storage Catalysts

    Monroe, D. R. / Li, W. / Society of Automotive Engineers | British Library Conference Proceedings | 2002


    Investigations of NO~x storage catalysts

    Fridell, E. / Skoglundh, M. / Johansson, S. et al. | British Library Conference Proceedings | 1998


    The new generation of NOx storage catalysts

    Koegel,M. / Carelli,G. / Goebel,U. et al. | Kraftfahrwesen | 2004


    Modelling of oxygen storage in automotive catalysts

    Khossusi, T / McCullough, G / Douglas, R | SAGE Publications | 2004