Abstract

The quality of the iron ore pellet and the yield of its drying process are directly affected by the drying condition. Such conditions are complex to be predicted or measured due to the heat and mass transfer process of the pellet in chain grate. However, it is difficult to measure the temperature and drying rate of the pellets directly due to the high temperature and the sealing of chain grate. In this paper, a model is established based on the computational fluid dynamics—discrete element method to describe the heat and mass transfer in updraught drying (UDD) in chain grate. The distribution of temperature field and the change of pellets drying rate in UDD are calculated and analyzed. The results indicate that the temperature gradient of pellet bed increases and the water content gradient decreases in movement direction and height direction of pellet bed. The temperature increasing rate and drying rate of the pellet bed show a trend from increasing to decreasing, and this is consistent with previous research. During this period, the temperature of pellet reaches a maximum value of 316 K and the drying rate of pellet reaches a maximum value of 0.42 kg/(m³ s). In addition, the temperature and the drying rate change little in the direction of width of pellet layer, which proves the rationality of simplifying UDD into a two-dimensional model. The proposed model can be used to predict the properties of the pellet drying process and optimize the process parameters.

Graphical Abstract

中文翻译：

---

基于CFD-DEM的链条炉Up进气干燥造粒过程的数值模拟。

摘要

铁矿石球团的质量及其干燥过程的产量直接受干燥条件的影响。由于链条炉排中颗粒的传热和传质过程，这种条件很难预测或测量。然而，由于高温和链g的密封，难以直接测量粒料的温度和干燥速率。在本文中，基于计算流体动力学离散元方法建立了一个模型，以描述链条炉排吸风干燥（UDD）中的传热和传质。计算并分析了UDD中温度场的分布和颗粒干燥速率的变化。结果表明，颗粒床的温度梯度沿颗粒床的移动方向和高度方向增加，含水量梯度减小。颗粒床的升温速率和干燥速率呈现出从升高到降低的趋势，这与以前的研究是一致的。在此期间，颗粒温度达到最大值316 K，干燥速率达到最大值0.42 kg /（m³  s）。另外，温度和干燥速率在颗粒层的宽度方向上几乎没有变化，这证明了将UDD简化为二维模型的合理性。所提出的模型可用于预测颗粒干燥过程的性质并优化过程参数。

图形概要