Yushkevich P. Development of energy-efficient converter tub combined blowing technology with oxygen and neutral gas using multideck tuyere

Technological process of combined oxygen and neutral gas blowing in a converter tub. Scientific proof and development of a new energy-efficient technology of a combined oxygen and neutral gas (nitrogen, argon) blowing in a converter bath with the use of a new construction of a multi-deck tuyere, which provides a stable purge process; improvement of the processes of slag formation and dephosphation of metal; increase efficiency of gas waste burning; prevention of intensive dumping of technological equipment; reduction of expenses for cast iron and slag-forming materials; increase of productivity for Ukraine metallurgical industry. Methods: thermodynamic analysis, the theory of metallurgical processes, cold and high-temperature simulation. For the first time we've got new information about hydro gas dynamics, heat and mass exchange processes which happen on the surface of the converter tub during blowing through the three-deck tuyere of a supersonic group and two groups of sound speed oxygen jets, formed by four Laval nozzles and eight cylindrical nozzles with a double-pointed tip and an upper 8-nozzle block, respectively, for different levels of the smelter-metal mixture foame. Based on the results of high-temperature and thermodynamic modeling, it is proved that, under the condition of high-temperature the effects are afterburning torches on lining, reduction of the scraping of the lance barrel and the converter throat, and a more efficient burning of carbon monoxide around-tuyere "fistula" channel, with the formation of carbon monoxide fluxes and metal droplets formed by a counter-directed double curtain of sound oxygen jets with the speed expansion area of 5 to 12 m / s. For the first time we've got scientifically proven a new method of combined purging of a converter bath using a three-deck tuyere, which provides a increase of slag formation and removes phosphorus, reduces consumption of cast iron and slag-forming materials, increases the efficiency of afterburning of waste gases preventing local deterioration of the lining and intensive scraping of the tuyere barrel and converter throat. Main construction parameters of three-deck tuyere calculation method are developed and proven. Production drawings of new three-deck tuyere construction and technical recommendations on blowing and slag modes of converter tub combined blowing using such tuyere for РJSC "ArcelorMittal Kryvyi Rih" 160-ton converters are created and proposed for implementation. The outcomes of this thesis are also recommended for use on 250-ton converter N°2 of Dneprovsky metallurgical combine (DMK, Kamenskoe Dnepropetrovsk region). The research results presented in this thesis are recommended for use during further development of automated control systems and intelligent decision support systems for the management of the combined blowdown process of the converter bath.