NH3 is an important volatile N-containing compound and a precursor for
NO(x) formation in fluidized bed combustion (FBC). This work focuses
on the influence of the sulfation process on the oxidation of NH3 to N
O catalysed by different CaO based sorbents and other bed materials (s
and, Al2O3). Experiments of simultaneous sorbent sulfation and oxidati
on of NH3 catalysed by the sorbents were performed in a laboratory fix
ed bed reactor in order to study changing catalytic activity. The infl
uence of SO2 on the oxidation of NH3 to NO for different bed materials
was investigated as well. The results show that desulfurization inter
feres with the catalytic conversion of NH3 to NO in two ways. First, C
aO based sorbents are active catalysts for the oxidation of NH3 to NO;
this catalytic activity decreases with an increase in the conversion
of CaO to CaSO4. For the limestones, which are subject to pore pluggin
g, the sorbents totally lose their activity for NO formation from NH3
when the maximum conversion of CaO to CaSO4 is reached. Second, the ca
talytic formation rate of NO decreases in the presence Of SO2 for some
bed materials. This means that the presence of SO2 inhibits oxidation
of NH3 to NO. Moreover, it appears that SO2 inhibits the decompositio
n of N2O on the surface of the catalysts as well.