US 12,252,399 B2
Bleaching tower and method for nitric acid production
Halvor Oien, Porsgrunn (NO); and Arnulf Idar Melgard, Skien (NO)
Assigned to YARA INTERNATIONAL ASA, Oslo (NO)
Appl. No. 17/422,682
Filed by YARA INTERNATIONAL ASA, Oslo (NO)
PCT Filed Feb. 14, 2020, PCT No. PCT/EP2020/053863
§ 371(c)(1), (2) Date Jul. 13, 2021,
PCT Pub. No. WO2020/169465, PCT Pub. Date Aug. 27, 2020.
Claims priority of application No. 19158885 (EP), filed on Feb. 22, 2019.
Prior Publication US 2022/0119258 A1, Apr. 21, 2022
Int. Cl. C01B 21/40 (2006.01); B01D 53/14 (2006.01); B01D 53/18 (2006.01)
CPC C01B 21/40 (2013.01) [B01D 53/1418 (2013.01); B01D 53/185 (2013.01); B01D 2257/40 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A vertical bleaching tower for removing dissolved nitrogen oxides from an aqueous nitric acid solution comprising said nitrogen oxides, using a stripping gas substantially devoid of nitrogen oxide gases, selected from air, nitrogen, oxygen or combinations thereof, in a process for producing nitric acid, the vertical bleaching tower comprising:
a structured packing;
a liquid distributor comprising a feed box having a serrated weir for distribution of the aqueous nitric acid solution comprising the dissolved nitrogen oxides through upward-pointing serrations of the serrated weir into perforated trays of the liquid distributor and located above the structured packing for distributing the aqueous nitric acid solution comprising the dissolved nitrogen oxides to the structured packing;
an aqueous nitric acid solution inlet;
an aqueous nitric acid solution outlet;
a stripping gas inlet; and
a stripping gas outlet.