侧顶复吹条件下AOD转炉熔池内流体的混合特性

Fluid Mixing Characteristics in an AOD Converter Bath under Conditions of Combined Side and Top Blowing Process

基于气体搅拌和流体流动的水模拟,在120tAOD炉的水模型装置上研究了侧顶复吹AOD过程中熔池内的混合.结果表明,侧顶复吹AOD过程具有良好的混合效果.侧吹主枪气量对熔池内的混合有决定性作用,适当增大副枪气量可使混合效率提高,顶枪气流使混合时间延长.给定的侧枪数和吹气量下,增大枪间夹角使混合时间缩短;给定的枪间夹角和吹气量下,增加侧枪数未必有类似效果,且会使单枪气量减小,使侧吹气流水平穿透距离变短.对应于6600m3/h的实际顶吹氧量,5枪、22.5°或6枪、27°能提供大体相当的良好混合效果.对120tAOD炉,在实际精炼条件下,7枪、18°并非合宜的侧枪配置,6枪、27°可在各精炼期提供良好的熔池混合.确定了混合时间与有关参数的关系.

Based on water modeling of the gas stirring and fluid flow, the mixing characteristics in the bath during the combined side and top blowing AOD process were investigated on a water model unit of 120 t AOD converter. The results indicated that the combined side and top blowing process possessed a good mixing efficiency. The gas flow rate of the side main tuyere had a decisive role on the liquid mixing in the bath. Raising suitably the gas flow rate of the subtuyere could improve mixing efficiency; and the gas jet from the top lance could prolong the mixing time. An increase in the angle between each tuyere could be advantageous for shortening the time. With a given angle between each tuyere and a given gas side blowing rate, increasing the side tuyere number could not necessarily reach definitely a similar result. In addition, it could decrease the gas flow rate of single tuyere, thus reducing the horizontal penetration of gas stream from side tuyere and making the high temperature (reaction) zone move towards, even close to the wall around the tuyere outlet, resulting in lowering the life of refractory lining. Corresponding to the oxygen top bowing rate of 6600 m3/h used for the practical process, a roughly equivalent and good mixing result could be attained by use of 5 tuyeres with an angular separation of 22.5° between each tuyere or 6 tuyeres with an angle of 27° between each tuyere. As far as only the mixing in the bath is concerned, for the 120 t AOD converter, under the conditions of practical refining, the existing 7 tuyeres with an angle of 18° between each tuyere would not be a suitable equipment and arrangement of side tuyere. Using 6 tuyeres with an angular separation of 27° between each tuyere could provide a good mixing in the various refining periods. The relationships of the mixing time with the related parameters were determined.