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K-Doped Co–Mn–Al Mixed Oxide Catalyst for N2O Abatement from Nitric Acid Plant Waste Gases: Pilot Plant Studies

Pacultová, K., Karásková, K., Kovanda, F., Jirátová, K., Šrámek, J., Kustrowski, P., Kotarba, A., Chromčáková, Ž., Kočí, K., Obalová, L.
Industrial & Engineering Chemistry Research 2016 v.55 no.26 pp. 7076-7084
catalysts, catalytic activity, engineering, gases, greenhouse gas emissions, models, nitric acid, nitrous oxide, potassium nitrate, wastes
The K-doped Co–Mn–Al mixed oxide deN₂O catalyst was prepared by calcination of Co–Mn–Al layered double hydroxide, subsequent impregnation with KNO₃, and shaping into tablets of 5 mm × 5 mm. Tablets were tested for N₂O decomposition in pilot scale reactor connected at the bypassed tail gas from the nitric production plant downstream of the SCR NOₓ/NH₃ catalyst with the aim to perform kinetic measurements. Special attention was paid to study the changes in the catalytic performance, which was monitored using both the long-term catalytic test and the comparison of physical–chemical properties of the fresh and used catalyst. The changes in the surface composition, caused by the time-on-stream operation for 112 days in the pilot reactor, provided stable catalytic performance; average value of N₂O conversion of 90 ± 6% at 450 °C was kept (GHSV = 11 000 m³ mbₑd–³ h–¹). The obtained kinetic data were applied in modeling of a full-scale reactor for the N₂O emissions abatement and can be used for estimation of the amount of the catalyst necessary for obtaining required N₂O conversion in the target plant.