Mushroom Formation by Water Model for Double-Tuyere in a Bottom-Blowing Process

摘要

A bottom blown oxygen steelmaking process known as the OBM or Q-BOP, has been adopted to efficiently agitate the bath in vessels to enhance the reaction rate. The method has eliminated the problem of rapid bottom lining deterioration encountered in earlier attempts to bottom blow oxygen. The tuyeres were design in such a way that the oxygen stream passing through a tuyere into the bath is surrounded by a sheath of hydrocarbon gas. By using a hydrocarbon gas, the washing effect on the refractory near the tuyere is significantly reduced. Additionally, the formation of relatively large solid built up at the tuyere tip, the so-called 'mushroom' prohibits the lining wear around the tuyere due to a more favorable flow characteristic of the melt that shifts the hot spot away from the tuyere tip and refractory. The protection of the tuyere by hydrocarbon, bottom blowing, results in shorter tap to tap times, better process control and longer refractory life in tuyere and slag zones, allowing for a longer lining life. In this study, a water model with a low temperature gas blow-in system was established to simulate the phenomena inside oxygen bottom-blowing vessels for investigating the effects of blowing conditions on the shape and size of solid accretion on the refractory lining near the tuyeres. The size of the ice mushrooms was found to be generally proportional to the outer gas flow rate and inversely proportional to the water temperature.