双层配碳烧结过程的传热传质分析

Analysis of heat and mass transfer in two-layer sintering process

为了研究双层配碳下的铁矿石烧结过程及其节能效益,建立了铁矿石烧结过程的二维非稳态数学模型。模型基于多孔介质理论,考虑了烧结过程中的主要物理变化和化学反应,以烧结杯为求解对象,利用FLUENT软件及C语言自定义编程对烧结过程进行了数值模拟,并利用烧结杯实验数据对模型进行了验证。通过对常规均匀配碳和双层非均匀配碳烧结的传热传质过程进行仿真计算,分析了两种烧结方式下床层温度和物料熔化分数分布,并通过熔化分数对烧结矿成品率进行判定。研究结果表明:在不改变整个床层配碳量的条件下,相对于单层均匀配碳,双层配碳条件下热效率更高,床层温度和物料熔化分数沿料层高度分布更加均匀;上下层物料配碳分别为5%和3.4%且料层厚度相同时,烧结成品率提高10%;降低上层高配碳区料层厚度,即当上下层厚度比为5:9,配碳为5%和3.756%时,成品率能够进一步提高。

In order to analyze two-layer sintering process and its energy-saving benefit, a two-dimensional unsteady mathematical model of iron ore sintering process, which considered major physical changes and chemical reactions was developed based on porous media theory. Employed with FLUENT software and C language programming via custom code, the sintering process was simulated and a sinter pot test was used to validate the model. Both conventional sintering process and two-layer sintering process were simulated. Distributions of temperature and melt fraction in sintering bed were analyzed. Results showed that heat efficiency became higher, temperature and melt fraction distributed more evenly in two-layer sintering when coke rate was kept the same as in one-layer sintering. Besides, the yield increased 10% when coke rates were 5% in the upper layer and 3.4% in the lower layer while two layers had the same heights. Reducing the height of the upper layer the yield of the sintering could be further increased when the height ratio of the upper and lower layer was 5：9 and coke rates were 5% and 3.756% respectively.