Process for the absorption of nitrous gases

Abstract

Nitric oxides can be absorbed from gas mixtures containing nitric oxides (NO and NO.sub.2) and oxygen by absorption with aqueous solutions. According to the invention, the absorption is effected in bubble columns, superficial velocities of 2 to 30 cm/second being maintained. It is advantageous to connect several bubble columns in series such that the gas and absorption liquid pass in counter-current to one another. In this embodiment, considerably less counter-current stages are required to achieve a high degree of absorption of NO.sub.x than in the case of conventional processes. At superficial velocities of 10 to 30 cm/second, large bubbles of gas can rapidly form from the gas introduced and can interact with the absorption liquid only with difficulty. In this case, gas distributor devices are incorporated in the bubble column. Since NO.sub.2 is more readily absorbed than NO, it is advantageous to connect flow reactors, in which NO.sub.2 is formed from NO and O.sub.2, upstream of the bubble columns.

Dependencies are inferred from the claim text.