Results of experiments are compared to simulations of the performance
of V2O5/gamma-alumina SCR catalyst used to remove nitrogen oxides from
diesel exhausts. The kinetic model is based on Eley-Rideal kinetics.
Temperature programmed desorption (TPD) of the ammonia is used to eval
uate adsorption/desorption parameters. Stationary experiments on a 3.6
-dm(3) engine with a 4.8-dm(3) honeycomb catalyst is used to evaluate
kinetic rate parameters for the reduction of NO with NH3. The desorpti
on activation energy, E(a,des), is best fitted as a function of surfac
e coverage yielding E(a,des) = 240 (1-0.44 * theta(NH3)(0.36)) kJ/mo
l. A dynamic test (FTP) with a 12-dm(3) engine and 24.8-dm(3) honeycom
b catalyst is done with a stoichiometric injection of ammonia. The NOx
conversion is 52%, but during the freeway traffic the conversion reac
hed 72%. The prediction of NOx conversion is good, but there are some
deviations for temperature and ammonia slip.