METHOD FOR PRODUCING NITRIC ACID WITH A TERTIARY REDUCTION IN NO AND NO EMISSIONS Russian patent published in 2022 - IPC C01B21/40 C01B21/26 B01D53/56 B01D53/86 B01J21/06 B01J23/22 B01J29/72 

FIELD: chemical processes.

SUBSTANCE: invention can be used in the chemical industry. The method for producing nitric acid includes a stage of catalytic oxidation of ammonia, producing a process gas containing nitrogen oxides NO_x and N₂O, and a stage of absorbing the process gas by water, producing a stream containing nitric acid and a stream 18 of tail gas containing NO_x and N₂O. The content of NO_x and N₂O in the gas stream 18 is reduced by passing said stream without any previous stage of removal of NO_x through the first stage 7 of deN₂O, using a catalyst based on an iron-containing zeolite for decomposition of N₂O, producing an effluent gas stream 19 with a reduced content of N₂O. The effluent stream of the deN₂O stage is then passed through the second deNO_x stage 8 using a V₂O₅-TiO₂ catalyst in the presence of ammonia gas as a reducing reagent. Gas streams containing N₂O and NO_x at the inlet of the first stage and the second stage have a temperature greater than 400°C. Proposed is a unit for producing nitric acid and a method for upgrading the unit.

EFFECT: inventions provide a possibility of reducing NO_x and N₂O emissions in the production of nitric acid without using an expensive catalyst and large capital expenses for equipment.

19 cl, 1 tbl, 2 ex, 1 dwg