含铁粉尘渣浴熔融还原处理过程渣滴群传热特性及多相传输动力学的研究

Slag bath smelting reduction process is a technology with high intensity of heat flow, high reaction efficiency, highly competitive capital and operating expenditure, and energy saving as well as environmental protection, which can be transformed and used to treat industrial iron-containing dust. It is not only the requirement for recycling economy and sustainable development of metallurgical industry, but also a feasible and effective way for application of smelting reduction iron-making technique to iron and steel industries in China. In the present proposed project, aiming at solving the requirement of “heat transfer from the upper zone to the lower one in reactor” during the smelting reduction treatment of iron-containing dust and multiphase transport behavior in reactor, on the basis of metallurgy transport theory and macrokinetics, a systematically fundamental scientific research is to be carried out to study the prereduction and melting behavior of dust particle in high temperature gas, movement behavior and macroscopic parameters of slag droplets in exhaust gas (residence time in gas phase, space position, and size), heat transfer mechanism and efficiency between slag droplets and post-combustion gas, flow fields of slag and iron baths and distribution pattern of carbon particle and iron droplet in slag bath, reduction and volatilization behavior of zinc in slag bath, and so on. The heat transfer feature of slag droplets and multiphase transport dynamics in the smelting reduction are to be identified. The impacting mechanism and effects of technological operation are to be clarified. The research results with high scientific relevance and practical value are to be used as the theoretical basis for the development of feasible technology for smelting reduction treatment process of iron-containing dust.

渣浴熔融还原炼铁技术具有热强度大、反应效率高、投资和生产成本低、节能环保等特点，可转化并应用于冶金含铁粉尘处理，这既是冶金工业循环经济和可持续发展的需要，也是熔融还原炼铁技术在我国钢铁企业推广应用的可行途径。本申请项目以含铁粉尘渣浴熔融还原工艺“上热下传”的传热特征及反应器内多相传输行为为研究对象，基于冶金传输原理及宏观动力学相关理论，针对处理过程含铁粉尘颗粒于高温炉气中的预还原与熔融动力学、气相中渣滴群运动行为及其宏观参数特征(停留时间、空间位置、尺寸)、渣滴群与二然炉气间传热机制及传热效率、渣(铁)浴流动特性以及碳粒和铁滴在渣浴中分布特征、渣浴中锌的还原挥发行为等相关科学问题进行深入系统研究，阐明含铁粉尘渣浴熔融还原过程渣滴群传热特性及多相传输动力学特征，掌握工艺操作的作用机制和影响规律。研究结果对于含铁粉尘熔融还原处理工艺可行性探索及技术开发具有重要学术意义和实际应用价值。

本项目以含铁粉尘渣浴熔融还原工艺中所涉及的“上热下传”特征以及反应器内多相传输为研究对象，基于冶金传输理论和宏观动力学，采用高温实验与数值模拟相结合的研究方法，围绕含铁粉尘颗粒于高温炉气中的气-固及气-液还原动力学、高温炉气中溅起渣滴群的运动行为及其宏观特征参数、渣滴群与高温炉气间的传热机制与效率、气体射流下的渣浴运动和喷溅特征、以及渣浴中金属液滴的聚并与沉降行为等开展了系统研究工作。揭示了含铁粉尘飞行过程中高温炉气温度及还原势、粉尘粒径对还原度的影响规律，掌握了含铁粉尘飞行还原过程中形貌与微观结构的演变规律，阐明了含铁粉尘飞行还原过程中气-固和气-液还原动力学机制及其限速环节，探究了高炉粉尘所含固定碳经由气化反应对炉气还原势的影响程度；建立了描述高温炉气中含铁粉尘颗粒飞行还原行为的数学模型，解析了飞行还原过程中粉剂颗粒的飞行轨迹以及气-固传热特征，明晰了高温炉气与粉尘颗粒间的表面辐射和对流换热机制；掌握了气体流量、喷枪枪位、熔渣粘度、熔渣表面张力等对渣池流动特性、渣池均混特性以及熔渣喷溅特征的影响，修正了渣浴中射流轴线轨迹表达式并确定了关键参数；开发了基于概率模拟Monte-Carlo法的渣滴产生、运动及传热数学模型，引入了渣滴尺寸分布函数，确定了高温炉气中渣滴群的飞行轨迹和停留时间，解明了炉气-渣滴间的传热机制和换热效率，确定了在高温炉气中具有较大换热效率的最适渣滴群尺寸分布；解明了渣浴内金属铁滴的沉降行为及其相互作用机制，掌握了熔渣黏度、渣金间密度差对金属铁滴沉降效率与聚合效果的影响规律，确定了机械搅拌对渣浴中金属铁滴的聚并及沉降效率的促进作用，阐明了搅拌器转速和结构的影响规律。项目共发表学术论文27篇，其中SCI收录22篇，EI收录1篇，申请国家发明专利2项。