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Catalysts for N2O removal from nitric acid plant tail gases – from laboratory to industrial application

L. Obalová

VSB-Technical University of Ostrava, Institute of Environmental Technology and Faculty of Metallurgy and Materials Engineering, 17. listopadu 15, 708 33 Ostrava, Czech Republic, Tel.: +420 597 321 532,
E-mail: lucie.obalova@vsb.cz


In last years, the catalytic decomposition of N2O as a method for abatement of N2O emissions in waste gases attracts increasing attention due to the expected inclusion of N2O in the greenhouse gas trade. Many research groups are focused on the development of suitable catalysts for this reaction because it is still a problem to find the catalyst with sufficient activity and stability in real off-gas conditions due to water, oxygen and NOx inhibition effects.
Mixed metal catalysts were prepared by calcination of layered double hydroxide, following impregnation by alkali metal salts and tested for N2O catalytic decomposition. Tuning of the catalyst properties was guided by catalytic tests of N2O decomposition including the effect of water, oxygen and NOx inhibitors, TPR-H2, SEM, XRD, XPS, N2 physisorption, alkali thermal desorption and in-situ work function measurements. The optimal composition of the catalyst revealed in the laboratory experiments was successfully reproduced in large scale synthesis and shaping. In the long-term pilot plant tests, high N2O conversion and sufficient stability of N2O removal from the tail gases of the nitric plant were reached.