Study On Optimal Design Of Staggered Nozzle Oxygen Lance For 200t Converter

Reasonable oxygen lance nozzle hole structure is the key to ensure the quality of oxygen jet,promote slagging,reduce blowing splash,and improve the oxygen utilization rate of the converter.In this paper,based on the structure of five-hole oxygen lance with equal diameter and equal inclination angle for a 200-ton converter,a six-nozzle arrangement with double inclination angles and staggered large and small holes is proposed.Based on the simulation research of jet characteristics and water model experiment,to explore the reasonable parameters of inclination angle and flow rate of large and small holes,so as to adjust the jet morphology,to delay the jet attenuation,control the fusion of the porous jet,and reduce the blowing splash,and then a theoretical guidance is provided for the optimization of the key structural parameters of oxygen lance nozzle with low splash and high slag melting capacity and the determination of injection process for the 200-ton converter.The main research content and conclusions are as follows:(1)The nozzle holes of the 200-ton six-hole staggered oxygen lance is proposed,where,three large inner holes with a large flow and small inclination,and three small outer holes with a small flow and large inclination.Based on the isentropic flow theory,the inclination angle of the inner and outer holes is selected as 12°/16°,the nozzle size was calculated under the flow ratio of 55%/45%,60%/40%,65%/35%espectively.Then,the characteristics of staggered jets with different structure sizes and jets of the equal-diameter and equal-inclination five-hole were simulated with FLUENT software used.It is concluded that staggered nozzles are superior to traditional five-hole nozzles in terms of coalescence behavior,axial velocity distribution,offset distance,radial dynamic pressure,and impact area;when the inclination angle of the inner and outer holes is 12°/16°,the nozzle arrangement with a flow ratio of 60%/40% is better for its long jet fusion distance and large effective impact area.(2)When the flow rate ratio of the inner and outer holes is 60%/40%,the influence of the inclination angle on the jet characteristics were analyzed.It is concluded that when the inclination angle of the inner and outer holes is changed from12°/16° to 14°/17°,the jet fusion distance of the inner hole changed a little.The jet fusion distance of the outer hole reduced by 0.1m.At the position of 25-40 times of the large hole exit diameter,the effective impact area reduced.(3)Based on the similarity theory,a 200 t converter water model experimental platform was built.The impact and stirring characteristics were analyzed,when the six-hole staggered nozzle and the traditional five-hole nozzle,interacted with molten pool respectively.It is concluded that the width and depth of the impact pit and the mixing time corresponding to the staggered nozzle jet are better than traditional five-hole nozzle;Under the same oxygen lance position,when the inclination angle of the inner and outer holes was changed from 12°/16° to 14°/17°,the impact width and the mixing time reduced,the amount of splash at the furnace mouth reduced,with better adaptability to the changing working conditions of oxygen lance position and oxygen gas flow rate.