One-dimensional steady-state thermal model for rotary kilns used in the manufacture of cement

Rotary kilns are used extensively in the cement industry to convert raw meal into cement clinker. In order to optimise the operation of cement kilns, computationally efficient thermal models are required. In this work, the development of a one-dimensional thermal model for kilns is explored. To simplify the model, the kiln is assumed to be well mixed in the transverse direction. A simultaneous mass and energy balance is solved based on a steady-state approximation. Existing semi-empirical models for heat transfer in the kiln are implemented and critically evaluated. The resulting one-dimensional model is capable of predicting axial temperature profiles in the rotary kiln which agree well with the available experimental data found in the literature. The model presented here extends from previous published models by considering a full enthalpy balance for the gas in the kiln. This allows the model to be used in a fully predictive manner, taking into account the temperature-dependent thermodynamic, transport, and radiative properties of the gas phase.

回转窑（Rotary Kiln）在水泥工业中应用广泛，用于将生料制备为水泥熟料。为优化水泥窑的运行工况，亟需具备高计算效率的热模型。本研究围绕窑炉一维热模型的构建展开探索。为简化模型，本研究假设窑炉在横向方向上完全混合，并基于稳态近似条件联立求解物料衡算与能量衡算方程。研究中采用了现有窑内传热半经验模型，并对其进行了批判性评估。所构建的一维模型可预测回转窑内的轴向温度分布，其预测结果与文献中已公开的实验数据吻合度较高。本研究提出的模型相较于既往已发表的模型，通过考虑窑内气体的完整焓衡算实现了拓展，使得模型可实现全预测性应用，同时能够考虑气相随温度变化的热力学性质、输运性质与辐射特性。