STUDYING THE POSSIBILITY OF USING COHERENT TYPE NOZZLES FOR BOF BLOWING AT THE GAS DYNAMIC SIMULATION STAND

Abstract

Introduction. The BOF technology is the leading one in the production of structural steel due to its undeniable advantages.Problem Statement. In the conditions of most Ukrainian converter shops, when the blowing parameters change significantly during the campaign (temperature of the lining, dimensions of the workspace, quality of scrap metal, temperature and composition of iron), and the bath is blown at a constant flow rate with conventional Laval nozzles, sometimes it is impossible to ensure a stable purging process with high rate of post-combustion of CO up to CO2. Therefore, one of the main problems of oxygen conversion is the improvement of the designs of blowing devices, in particular, the nozzles.Purpose. The purpose of this research is to study the possibility of using nozzles of the coherent type for the top oxygen blowing of the converter.Material and Methods. In the research, we have used samples of coherent-design laboratory nozzles having different central part-to-periphery ratio under fixed equal general conditions of jet output (percentage of the annular gap to the total area of the nozzle, %: 75, 65, 50, 45, 35, 25). They have been studied by calculating the jet momentum, through weighing and taking shadow shots when the gas flow velocity reaches 2 M. The results have been compared with those for the cylindrical nozzle.Results. When the gas is supplied at 2 M, the coherent-type nozzles with a fraction of the outer part of 65—75% contribute to the formation of 1.5—1.6 times wider jets as compared with the cylindrical nozzle, with a multinode structure. It helps to increase the jet momentum by 45—55%.Conclusions. The design of a coherent type nozzle with an outer part share of 75% can be recommended to be used as the second tier or the second level nozzles of the top oxygen lance for post-combustion in an oxygen converter due to an increase in the surface area of the jet contact. The efficiency of post-combustion of CO from waste converter gases is expected to increase due to the increasing reaction surface area of additional oxygen jets.