PROCESS FOR REDUCING NO AND NO CONTENT IN TAIL GAS OF NITRIC ACID PRODUCTION Russian patent published in 2023 - IPC B01D53/86 C01B21/40 

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a method for reducing the content of NO_x and N₂O in the tail gas of a process for producing nitric acid. The method for reducing the content of NO_x and N₂O in the inlet tail gas of the nitric acid production process includes an emission reduction stage, including at least a deN₂O stage and a deNO_x stage and producing a purified tail gas with a temperature higher than that of the inlet tail gas. The tail gas temperature is less than 400°C. Before entering the emission reduction stage, the inlet tail gas is heated to a temperature of at least 400°C by indirect heat exchange with at least a portion of the purified gas. The deN₂O and deNO_x steps are carried out in separate catalyst beds. The deNO_x step is carried out in the presence of at least one of the following catalysts: a vanadium catalyst, a copper-containing zeolite catalyst, and an iron-containing zeolite catalyst. Also claimed is a system for reducing the content of NO_x and N₂O in the tail gas of the nitric acid production process and a method for obtaining the system by reconstructing the existing system. EFFECT: group of inventions provides reduction of NO_x and N₂O content in the incoming tail gas of the nitric acid production process, provides efficient decomposition of N₂O using iron-based zeolites, and also provides tertiary and quaternary reduction of NO_x and N₂O emissions from tail gas process for producing nitric acid, the temperature of which is less than 400°C.

15 cl, 1 dwg, 1 ex