The Mechanisms And Effects Of Spray Cooling Of Large Converter

Preventing distortion of the steel shell of the converter has been a hot point project in today's research on steelmaking in the world. The main reason of distortion is that the shell has worked at elevated temperature. One potential solution in reducing the shell temperature is the use of an evaporative cooling device- Hi-Vap cooling system. In this paper, the mechanisms and effects of spray cooling of Basic Oxygen Furnace (BOF) were studied. They are mainly as follows:1.Studyed here were the cooling mechanisms, heat transfer, temperature control principle, effects on shell's mechanical character, the behavior of the spray nozzle and working parameters of Hi-Vap spray cooling system. This is the first domestic study on spray cooling of large converter.2.The steady state experiment with multi-parameters on the characteristics of heat transfer has been finished. A new formula of heat transaction coefficient (HTC) was derived based on empirical method and it is widely suitable for the spray cooling system applied to converter. It is found that covering the shell body with liquid film continuously is the key factor affecting the cooling intensity. It provides theoretical foundation for practical use of spray cooling system in BOF shell.3.The instant-temperature-field FEA model for the converter has been established. The distributions and variations of the instant-temperature-field of spray cooling were evaluated. It is found that the shell temperature line is a zigzag line-it goes down fast, goes up slowly. The average cooling velocity is 2~2.5℃/min. With spray cooling system, the shell temperature can be controlled under material's creeping temperature(about 400℃).4.A FEA model has been established for multi-parameter-coupled nonlinear computation applied to the converter with Hi-vap cooling device. It was the first time to study the level and distribution law of thermal stress and its relation with heat transfer. It is pointed that the compositive thermal stress of shell changes with the temperature, and the phase between them is...