【摘要】 研究了侧顶复吹条件下AOD精炼过程中熔池内的传质特性.实验在120 t侧顶复吹AOD转炉1/4的水模型装置上进行,采用分析纯氯化钠作粉剂,在AOD过程的条件下,测定了液体内溶质(NaCl)的传质系数.考察了侧吹和顶吹气量、侧枪枪位及支数、粉剂(气泡)尺寸等对传质速率的影响.结果表明,本工作条件下,熔池液体内溶质的传质系数在7.31×10-5~3.84×10-4m/s范围内;对给定侧枪支数和侧吹气量的纯侧吹过程,传质系数随相邻两侧枪间夹角的增大而非线性增大;侧吹主枪气体对熔池内的传质特性有决定性的作用,而顶吹气体射流使传质速率减小,相应的传质系数比纯侧吹下要小,顶吹气量越大越明显;增大颗粒(气泡)尺寸使传质系数增大;对应于实际工艺所规定的顶吹气量,7枪、22.5°和6枪、27°以及5枪、22.5°的侧枪配置均能提供较大的传质速率.分别考虑颗粒与液流的相对速度,紊流中脉动速度引起的能量耗散和将颗粒与钢液间的传质视为刚性的气泡与钢液间的传质,得到了有关的无量纲关系式.更多还原

【Abstract】 The mass transfer characteristics in the bath during the AOD refining process with the conditions of side and top combined blowing were investigated.The experiments were conducted on a water model unit of 1/4 linear scale for a 120 t side and top combined blowing AOD converter.Sodium chloride powder of analytical purity was used as the flux for blowing,and the mass transfer coefficient of solute(NaCl) in the liquid was determined under the conditions of the AOD process.The effects of the gas flow rates of side and top blowing processes,the position and number of side tuyere,the powder flux particle(bubble) size and others on the characteristics were examined.The results indicated that,under the conditions of the present work,the mass transfer coefficient of solute in the bath liquid is in the range of(7.31×10-5～3.84×10-4)m/s.The coefficient increases non-linearly with increasing angle between each tuyere,for the simple side blowing process at a given side tuyere number and gas side blowing rate.The gas flow rate of the main tuyere has a governing influence on the characteristics,and the gas jet from the top lance decreases the mass transfer rate,the relevant coefficient being smaller than that for a simple side blowing.Also,in the range of particle(bubble) size used in the present work and with all other factors being constant,raising particle(bubble) size increases the coefficient.Excessively fine powder(bubble) sizes are not advantageous to strengthening the mass transfer.Corresponding to the oxygen top blowing rate specified by the real technology used,the side tuyere arrangements of 7 and 6 tuyeres with an angular separation of 22.5° and 27° between each tuyere,as well as 5 tuyere with an angle of 22.5° between each tuyere can all provide a larger mass transfer rate.Considering respectively the relative velocity of the particles to the liquid,the energy dissipation caused by the fluctuation in the velocity of the liquid in turbulent flow and regarding the mass transfer as that between a rigid bubble and molten steel,the related dimensionless relationships for the coefficient were obtained.更多还原