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Selective catalytic reduction of NOx with NH3 over H-ZSM-5: Influence of transient ammonia supply

Mikaela Wallin (Institutionen för material- och ytkemi, Teknisk ytkemi ; Kompetenscentrum katalys (KCK)) ; Carl-Johan Karlsson (Institutionen för material- och ytkemi, Teknisk ytkemi ; Kompetenscentrum katalys (KCK)) ; Magnus Skoglundh (Institutionen för material- och ytkemi, Teknisk ytkemi ; Kompetenscentrum katalys (KCK)) ; Anders Palmqvist (Institutionen för material- och ytkemi, Teknisk ytkemi ; Kompetenscentrum katalys (KCK))
Journal of Catalysis (0021-9517). Vol. 218 (2003), 2, p. 354-364.
[Artikel, refereegranskad vetenskaplig]

The effect of ammonia supply on the selective catalytic reduction of NOX over zeolite H-ZSM-5 was investigated using step response experiments between 200 and 500 degrees C. For inlet NO:NO2 ratios > 1, the activity for NOX reduction transiently increased when NH3 was removed from the feed. For NO:NO2 ratios less than or equal to 1, the NOX reduction however decreased. By pulsing NH3 to the feed, the activity for NO reduction was enhanced up to five times compared to continuous supply of ammonia. For NO:NO2 ratios exceeding one, also the selectivity towards N2O formation was lower with transient ammonia supply. Temperature programmed reaction experiments with preadsorbed NH3 showed highest initial NOX reduction activity when ammonia had been adsorbed at 300 or 250 degrees C compared to 200 degrees C. A minimum in NO reduction was observed at 130 degrees C independent of the ammonia adsorption temperature. For NO:NO2 ratios > 1, the results strongly indicate that NO oxidation is the rate determining step in the ammonia selective catalytic reduction (NH3-SCR) reaction over H-ZSM-5.

Nyckelord: H-ZSM-5; selective catalytic reduction; NOx reduction; ammonia transients; lean deNOx



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Denna post skapades 2009-01-26. Senast ändrad 2012-02-20.
CPL Pubid: 88904

 

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Institutioner (Chalmers)

Institutionen för material- och ytkemi, Teknisk ytkemi (2002-2004)
Kompetenscentrum katalys (KCK)

Ämnesområden

Energi
Materialvetenskap
Nanovetenskap och nanoteknik
Transport
Hållbar utveckling
Kemi
Kinetik
Spektroskopi
Kemiteknik

Chalmers infrastruktur

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