T. Ishihara et al., THERMOSTABLE MOLECULAR-SIEVES, SILICOALUMINOPHOSPHATE (SAPO)-34, FOR THE REMOVAL OF NOX WITH C3H6 IN THE COEXISTENCE OF O-2, H2O, AND SO2, Industrial & engineering chemistry research, 36(1), 1997, pp. 17-22
Selective reduction of NO with C3H6 under an oxidizing atmosphere was
studied over various Cu ion-exchanged molecular sieves. All examined C
u ion-exchanged catalysts are active for NO reduction with C3H6 in a l
arge excess of O-2; however, the temperature at the maximum NO convers
ion depends on the kind of molecular sieves. In particular, it was fou
nd that Cu-SAPO-34 is sometimes more active than Cu-ZSM-5. Thermal sta
bility of SAPO-34 was extremely high, and consequently, decrease in th
e activity to NO selective reduction on Cu-SAPO-34 was negligible over
60 h at 673 Kin an atmosphere containing 15 vol % H2O. After thermal
treatment at 1073 R in a humidified atmosphere, decrease in the activi
ty to NO reduction was also small. Although the activity of Cu-SAPO-34
to NO reduction was decreased slightly with the coexistence of SO2, i
t is expected that the activity of Cu-SAPO-34 is sustained over a long
period.