Selective catalytic reduction of NOx with NH3 over H-ZSM-5: Influence of transient ammonia supply
Artikel i vetenskaplig tidskrift, 2003

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.

H-ZSM-5

NOx reduction

selective catalytic reduction

lean deNOx

ammonia transients

Författare

Mikaela Wallin

Chalmers, Institutionen för material- och ytkemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Carl-Johan Karlsson

Chalmers, Institutionen för material- och ytkemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Magnus Skoglundh

Kompetenscentrum katalys (KCK)

Chalmers, Institutionen för material- och ytkemi, Teknisk ytkemi

Anders Palmqvist

Chalmers, Institutionen för material- och ytkemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Journal of Catalysis

0021-9517 (ISSN) 1090-2694 (eISSN)

Vol. 218 354-364

Drivkrafter

Hållbar utveckling

Styrkeområden

Nanovetenskap och nanoteknik

Transport

Energi

Materialvetenskap

Ämneskategorier

Fysikalisk kemi

Kemiteknik

Kemi

DOI

10.1016/S0021-9517(03)00148-9