BLEACHING COLUMN AND METHOD FOR NITRIC ACID PRODUCTION Russian patent published in 2023 - IPC C01B21/46 C01B21/40 B01D53/18 

FIELD: chemical industry.

SUBSTANCE: vertical bleaching column is proposed for removing dissolved nitrogen oxides from an aqueous nitric acid solution containing nitrogen oxides using a stripping gas in which the content of gaseous nitrogen oxides is less than or equal to 5 wt.%, such as air, nitrogen, oxygen or combinations thereof, in process for the production of nitric acid. The bleaching column contains a regular attachment; a liquid distributor that contains a loading box having a serrated baffle for distributing an aqueous solution of nitric acid containing dissolved nitrogen oxides through upwardly facing teeth of the serrated baffle into perforated liquid distributor trays, and which is located above the regular attachment for distributing an aqueous solution of nitric acid containing dissolved nitrogen oxides into the regular attachment; inlet and outlet channels intended for an aqueous solution of nitric acid; and inlet and outlet channels for stripping gas. A method for bleaching an aqueous solution of nitric acid, a method for producing nitric acid, the use of a vertical bleaching column, and the use of a regular packing in combination with a liquid distributor are also proposed.

EFFECT: inventions make it possible to increase the productivity of nitric acid while reducing the amount of stripping gas used and maintaining low concentrations of dissolved nitrogen oxides NO₂ and N₂O₄ in an aqueous acid solution.

12 cl, 4 dwg, 1 tbl