OXIDATION OF NITROGEN OXIDES BY OXYGEN IN THE LIQUID PHASE

Abstract

Atmospheric air pollution ranks first in the degree of chemical danger to humans. Nitrogen oxides are among the most common and dangerous air pollutants on our planet. Waste gases, which include nitrogen oxides, are produced in a number of chemical industry productions, in oil refining processes, and during fuel combustion. The sources of waste gas emissions differ in their content of nitrogen oxides and other impurities, the degree of oxidation of nitrogen (II) oxide, temperature and pressure. Oxidation methods of sanitary purification of waste gases from nitrogen oxides based on preliminary oxidation of nitrogen (II) oxide with subsequent absorption of nitrogen (IV) and nitrogen (III) oxides (NO2, N2O3) by various absorbers are described in the work. The rate of oxidation of nitrogen (II) oxide is the limiting stage of the overall process to nitrogen (IV) oxide. Since this reaction takes place in the gas phase, absorption devices must have a fairly large free volume, so the absorption process is carried out in multi-stage packed or plate columns. In experiments on the absorption of nitrogen oxides by various liquid absorbers, the degree of absorption was 80–90%. In the process of absorption, nitrogen oxides are oxidized not only in the gas phase, but also in the liquid phase. Research was directed to the intensification of the process of oxidation of nitrogen (II) oxide in the liquid phase. The paper compares the results of studies on the rate of NO oxidation in the gas and liquid phases. The principle of oxidation in the liquid phase is included in the development of an absorption unit for the production of nitric acid. It has been proven that the intensification of the process of absorption of nitrogen oxides is possible by increasing the proportion of NO that is oxidized in the liquid phase. This is achieved by saturating the working solution with oxygen.