Oxide catalysts for ammonia oxidation in nitric acid production: properties and perspectives

This paper generalizes the results of long-term efforts aimed at research a nd development of industrial oxide catalysts for ammonia oxidation in the n itric acid production within two-bed (Pt gauzes + monolithic oxide layers) technology of the high pressure process. Main factors determining performance of precious metals and oxides in the h igh-temperature ammonia oxidation are considered. The surface oxygen bondin g strength determined by the surface atomic structure appears to be the mos t important. From this point of view, existing approaches to synthesis of m ixed oxide systems including perovskites with controlled nitric oxide selec tivity and good stability in the high-temperature process of ammonia oxidat ion are analyzed. Main features of the bulk oxide monolithic catalysts prod uction technology and principles of a two-bed system design based upon the process mathematical modeling are briefly outlined. Proven economic benefit s of this technology recently commercialized in Russia at nitric acid plant s are debated. (C) 2000 Elsevier Science B.V. All rights reserved.