	US 11,925,900 B2
	Process for reducing the content of NOx and N2O from a tail gas of a nitric acid process
Fabio Laurenzi, Lugano (CH); Raffaele Ostuni, Lugano (CH); and Jean Francois Granger, Angoulins (FR)
Assigned to CASALE SA, Lugano (CH)
Appl. No. 16/976,863
Filed by CASALE SA, Lugano (CH)
PCT Filed Feb. 19, 2019, PCT No. PCT/EP2019/054025 § 371(c)(1), (2) Date Aug. 31, 2020, PCT Pub. No. WO2019/166267, PCT Pub. Date Sep. 6, 2019.
Claims priority of application No. 18159533 (EP), filed on Mar. 1, 2018.
Prior Publication US 2021/0069643 A1, Mar. 11, 2021
Int. Cl. B01D 53/34 (2006.01); B01D 53/14 (2006.01); B01D 53/86 (2006.01); C01B 21/26 (2006.01); B01D 53/56 (2006.01)

CPC B01D 53/8628 (2013.01) [B01D 53/14 (2013.01); B01D 53/343 (2013.01); B01D 53/869 (2013.01); C01B 21/265 (2013.01); B01D 53/565 (2013.01); B01D 2255/20738 (2013.01); B01D 2255/50 (2013.01); B01D 2259/65 (2013.01)]

13 Claims

1. A process for reducing the content of NOx and N2O from an input tail gas produced in a nitric acid process, said input tail gas having a temperature lower than 400° C., the process comprising:

an abatement stage including at least a stage of catalytic N2O decomposition (deN2O) over an iron-loaded zeolite catalyst and a stage of catalytic NOx reduction (deNOx), said abatement stage providing a conditioned tail gas having a temperature greater than the input tail gas, wherein:

prior to submission to said abatement stage, said input tail gas is pre-heated to a temperature of at least 400° C. by indirect heat exchange with at least a portion of said conditioned tail gas;

said deN2O and deNOx stages being carried out:

in separated catalytic beds and said deNOx stage being carried out over at least one of: a vanadium catalyst, a copper-loaded zeolite catalyst, or an iron-loaded zeolite catalyst, or

concurrently in the same catalytic bed over at least an iron-loaded zeolite catalyst.