Semi-industrial technology tests of the sanitary cleaning of metallurgical enterprises waste gases from sulfur and nitrogen oxides

Abstract

Nitrogen emissions in the form of NOx with flue gases from thermal power plants are the most serious pollutants generated during the combustion of coal. The calcium carbonate gas scrubbing process used today is expensive, generates a lot of waste, and leaves a significant amount of SO2 in the gas. Virtually no NOx removal. In this paper, we consider the behavior of nitrogen oxides during the purification of exhaust gases from thermal power plants with a carbonate melt of alkali metals. Based on the thermodynamic analysis of reactions between NOx and alkali metal carbonates, the possibility of reducing their concentrations in the exhaust gases is shown. It has been established that the process of NOx absorption in the temperature range of 573…823K is accompanied by the formation of stable potassium nitrite (KNO2) in the melt, as evidenced by the high negative values of the Gibbs energies of the reactions. The results of balance experiments fully confirm the established regularities. One can foresee that carbonate melt-based SO2 removal may become a practical and economical scrubbing method for sulfur-poor flue gases emitted by nonferrous metal production plants, thereby contributing to the limiting of harmful sulfur and NOx emissions into the atmosphere. The research was carried out within the framework of grant funding of the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan for 2020–2022 in the priority area “Rational use of natural resources, including water resources, geology, processing, new materials and technologies, safe products and structures” project No. AP08856384 “Development of a new high-tech technology for the utilization of the SO2 and CO2 from flue gases from thermal power plants and metallurgical plants with the production of marketable products”.