Thermally Durable Vanadium-SCR Catalysts for Diesel Applications Ecocat

Format:

Conference/Event

Author/Creator:

Maunula, Maunula, author.

Contributor:

Kanniainen, Kauko

Kinnunen, Toni

Savimaki, Auli

Viitanen, Arto

Conference Name:

SAE 2013 World Congress & Exhibition (2013-04-16 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2013

Summary:

The emission regulations for mobile applications will becomestricter in Euro 4 - 6 levels and require the use of activeaftertreatment methods (deNOx and DPF) in addition topassively operating diesel oxidation catalysts (DOC).Vanadium-SCR (V-Selective Catalytic Reduction) catalysts basedon stabilized TiO₂-WO₃ raw materials and tailored preparationmethods were first evaluated by the laboratory experiments.Conventional V-SCR catalysts were durable up to about 600°C but thedeveloped catalyst stand hydrothermal ageing up to 700°C withoutlosses of activity. Simultaneously, the performance at 250 - 450°Cwas about the same as with the traditional V-SCR catalyst and theSCR selectivity at 450 - 600°C was high with a low NH₃ oxidationtendency. Coated V₂O₅/TiO₂-WO₃ catalysts (ceramic and metallicsubstrates) were evaluated with a 4.9 L engine by engine benchexperiments. The new V-SCR catalyst kept the SCR activity alsoafter ageing at 700°C when the conventional V-SCR catalyst lostdrastically the activity. NOx conversions (DOC+SCR, 300cpsi ceramic) without NH₃ slip as 700°C aged were 59 - 96% with thenew concept and 21 - 68% with the reference in steady engine points(250 - 530°C, 19.000 - 51.000 h-₁). The surface area and acidity(NH₃ adsorption capacity) measurements showed the improvedstability. The use of ammonia slip catalyst (ASC) in system enabledthe high NH₃/NOx ratios without NH₃ emissions andextended both low and high temperature SCR performance.The durable V-SCR catalyst is an alternative to zeolite-SCRcatalysts in DOC+DPF+SCR systems. In the presence of DPF withactive regeneration, exhaust gas is heated up to 700°C, which isvery demanding for downstream-located SCR. The integration of thiskind V-SCR coating on DPF was also discussed as an opportunity

Notes:

Vendor supplied data

Publisher Number:

2013-01-1063

Access Restriction:

Restricted for use by site license