Impact of Thermal and Chemical Ageing of Fe-BEA SCR Catalyst on NOx Conversion Performance

• Emissions of nitrogen oxides (NOx) from heavy-duty diesel engines are subject to more stringent environmental legislation. Selectivecatalytic reduction (SCR) over metal ion-exchanged zeolites is in this connection an efficient method to reduce NOx. Understandingdurability of the SCR catalyst is crucial for correct design of the aftertreatment system. In the present paper, thermal and chemicalageing of Fe-BEA as NH3-SCR catalyst is studied. Experimental results of hydrothermal ageing, and chemical ageing due tophosphorous and potassium exposure are presented. The catalyst is characterized by flow reactor experiments, nitrogen physisorption,DRIFTS, XRD, and XPS. Based on the experimental results, a multisite kinetic model is developed to describe the activity of the freshFe-BEA catalyst. Furthermore, the model can predict deactivation of the catalyst well by decreasing the number of active sites,representing loss of active iron sites due to migration or chemical blockage of the sites. By performing a systematic study of differentdeactivation mechanisms, a deactivation expression for the active sites can be formulated.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

NATURVETENSKAP  -- Matematik (hsv//swe)

NATURAL SCIENCES  -- Mathematics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Kemiska processer (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Chemical Process Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

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