METHOD OF PREPARATION OF NITRIC ACID Russian patent published in 2001 - IPC

FIELD: preparation of nitrogen oxides and conversion thereof to nitric acid. SUBSTANCE: process of catalytic oxidation of molecular nitrogen is carried out at pressure similar to that at stage of absorption of the resulting nitrogen oxides with water, and energy for endothermal process of catalytic oxidation of molecular nitrogen is supplied with flow of streams directly into reaction zone. Process of catalytic oxidation of molecular nitrogen is carried out at temperatures of lower than 1000 C and at content of oxidizer in gas phase in front of catalyst of lower than 10 vol % of HNO₃+NO× vapors and at pressure of up to 25 atm in system. Catalysts for oxidation of molecular nitrogen include platinum alloys with platinum group metals or catalysts based on ferric, cobalt, chromium, aluminum oxides with promoting additives of high-melting metals. In order to form stream with oxidizer, not only atmospheric air, but gas mixture resulting from blowing off product acid is used. EFFECT: lower energy consumption, reduced capital outlays and simplified flowsheet of nitric acid production. 8 cl, 1 dwg, 1 ex, 2 tbl