CobaltSpinel Catalyst for N2O Abatementin the Pilot Plant Operation–Long-Term Activity and Stabilityin Tail Gases.

Thecatalytic activity of a doubly promoted K/Zn–Co3O4spinel catalyst in the deN2O reactionwas tested for 10 weeks in a nitric acid pilot plant. A charge of15 kg of the catalyst was synthesized via precipitation method, dried,calcined, and formed into 5 × 5 mm tablets. The catalytic testswere carried out in the wide range of process parameters: 320 < T< 425 °C; 80 < VRG< 180 N m3·h–1, 3 < p< 9.5 bar(a). During the operation the chemical compositionof tail gases from ammonia oxidation reactor outlet varied withinthe following range: 300 < CN2O<1500 ppm(v); 30 < CNOx< 3000 ppm(v);10000 < CO2< 50000 ppm(v); 1000< CH2O< 18000 ppm(v); N2– rest. In these conditions, the N2O conversionwas above 70% at 400 °C and was stable in time. Fresh and usedcatalysts were compared through detailed structural and morphologicalcharacterization (XRD, Raman, BET, SEM, XPS, H2-TPR), andtheir deN2O performance was verified in laboratory conditions.Long-term catalytic tests proved persistent stability of the catalystwith respect to its high activity, composition, structure, and morphology. [ABSTRACT FROM AUTHOR]