US 12,410,108 B2
NOx removal from gaseous effluents
Robertus Louwe, Porsgrunn (NO); Patrycja Kita, Poznań (PL); and Lene Sund, Porsgrunn (NO)
Assigned to YARA INTERNATIONAL ASA, Oslo (NO)
Appl. No. 17/045,165
Filed by YARA INTERNATIONAL ASA, Oslo (NO)
PCT Filed Apr. 5, 2019, PCT No. PCT/EP2019/058604
§ 371(c)(1), (2) Date Oct. 3, 2020,
PCT Pub. No. WO2019/193137, PCT Pub. Date Oct. 10, 2019.
Claims priority of application No. 18166040 (EP), filed on Apr. 6, 2018.
Prior Publication US 2021/0147308 A1, May 20, 2021
Int. Cl. C05B 11/04 (2006.01); B01D 11/04 (2006.01); B01D 53/14 (2006.01); B01D 53/34 (2006.01); B01D 53/56 (2006.01); B01D 53/76 (2006.01); B01D 53/78 (2006.01); C05B 11/06 (2006.01); C05B 11/08 (2006.01)
CPC C05B 11/06 (2013.01) [B01D 11/04 (2013.01); B01D 53/1431 (2013.01); B01D 53/1456 (2013.01); B01D 53/346 (2013.01); B01D 53/56 (2013.01); B01D 53/76 (2013.01); B01D 53/78 (2013.01); C05B 11/04 (2013.01); C05B 11/08 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A process for the reduction of mono-nitrogen oxides (NOx) from a gaseous effluent generated in the production of fertilizer comprising the acid digestion of phosphate ore in the presence of urea, wherein said gaseous effluent generated has a NOx composition of 70 to 100 mole % NO2 and 0 to 30 mole % NO, comprising the steps of:
a) contacting said gaseous effluent for 0.5 to 15 seconds with ozone, thereby providing a resultant gas mixture wherein NO and NO2 present in the NOx are oxidized to higher nitrogen oxides; and;
b) removing higher nitrogen oxides from said resultant gas mixture;
wherein urea is added during said acid digestion of phosphate ore in an amount between 0.001 wt % and 0.25 wt % based on the weight of said phosphate ore; and;
ozone is added to said gaseous effluent in an ozone/NOx ratio ranging between 0.5 and 1.4,
wherein the resultant gas mixture has an NOx level of 20 to 80 ppm and an N2O level of less than 15 ppm.
 
14. A process for the removal of mono-nitrogen oxides (NOx) from gaseous effluents in the production of fertilizer, the process comprising digesting phosphate ore with acid, thereby forming a digesting mixture and gaseous effluents; adding urea to the digesting mixture; and adding ozone to the gaseous effluents, wherein the gaseous effluents generated in the production of fertilizer have a NOx composition of 70 to 100 mole % NO2 and 0 to 30 mole % NO, and wherein urea is added in the digesting mixture in an amount between 0.001 wt % and 0.07 wt % based on the weight of said phosphate ore.