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

This paper generalizes the results of long-term efforts aimed at research and development of industrial oxide catalysts for ammonia oxidation in the nitric 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 high-temperature ammonia oxidation are considered. The surface oxygen bonding strength determined by the surface atomic structure appears to be the most important. From this point of view, existing approaches to synthesis of mixed oxide systems including perovskites with controlled nitric oxide selectivity and good stability in the high-temperature process of ammonia oxidation are analyzed. Main features of the bulk oxide monolithic catalysts production technology and principles of a two-bed system design based upon the process mathematical modeling are briefly outlined. Proven economic benefits of this technology recently commercialized in Russia at nitric acid plants are debated. (C) 2000 Elsevier Science B.V. All rights reserved.