MATHEMATICAL MODEL OF METAL SCRAP HEATING IN THE CONVERTER WITH A COAL TORCH

Abstract

Increasing requirements for energy efficiency and the level of competitiveness of domestic metal products led to the development of new technological solutions to increase the share of scrap metal in the charge of oxygen-converter melting. Data on temperature distribution in the working space of the converter and in the layer of scrap metal during its pre-heating using standard oxygen or special fuel-oxygen nozzles are limited and do not go beyond the scope of scientific assumptions. The results of numerous simulations of the process of heating metal scrap in the working space of an oxygen converter with a high-temperature torch formed by burning pulverized coal fuel in an oxygen stream using a fuel-oxygen nozzle are presented. A mathematical model of heating scrap metal in the working space of the converter with a pulverized coal torch was built and its software implementation has been done in the Visual Studio 2022 environment in the C# language. With the help of the model, a series of RO-calculations was carried out, which proved its qualitative adequacy of the process under consideration. The results of the calculation with the determination of the fields of velocities and temperatures in the working space of the converter during the heating of scrap metal are presented. It was established that the direction of heat transfer is determined by gas flows caused by a high-temperature torch. Upon reaching the metal scrap, the gas flows lead to its gradual heating, which generally corresponds to the qualitative picture of the simulated process.The dependence of the distribution of gas flows on the shape of the surface of the scrap loaded into the converter is shown. It was established that local vortices can form in the depths of the scrap surface during heating by a high-temperature torch. But the general characteristic of the gas-dynamic picture in the working space of the converter is the formation of two global vortices: one near the torch with counterclockwise rotation (in the sections shown), and the other clockwise with the formation of downward gas flows near the inner surface of the converter. These vortices mainly determine the thermal pattern in the working space of the converter and, in particular, the fact that the scrap near the wall of the converter will warm up less.