Penetration behaviour of an annular gas-solid jet impinging on a liquid bath: effect of the annular cross-sectional area

Top blow injection of a gas-solid jet through a circular lance is used in the Mitsubishi continuous smelting process. One of the problems associated with such injection is the severe erosion of the hearth refractory below the lances. A new configuration of the lance to form an annular gas-solid jet rather than the circular jet was designed in this laboratory. With this new configuration, solid particles, fed through the centre tube, leave the lance at a much lower velocity than the gas, and the penetration behaviour of jet is significantly different than that of circular lance where the solid particles leave the lance at the same high velocity as the gas. In an earlier cold model investigation, the effects of gas velocity, solid feedrate and lance height of the annular lance were studied and compared to the circular lance. This paper reports on experimental work that includes the effects of the size of the annular lance, which greatly expands the applicable range of the developed correlation. It has been shown that the variation in penetration depth with the annular jet cross-sectional area depends strongly on the mass loading of the solid particles. A correlation equation for the penetration depth that shows a good agreement with the measured values has been developed.