Abstract

A mathematical model for a co-current moving bed heat exchanger (MBHE) is presented. The bed is diluted and composed of spheres of uniform radius which are transported by a dragging fluid in plug flow. The gas-solid mixture is heated indirectly by a flue gas, which flows in a jacket around the MBHE. Intraparticle temperature gradients and thermal losses to the external environment are considered. The model is solved analytically by the Self-Adjoint Operator method (SAO) and numerically by a combination of the Finite Analytical (FA) and the Finite Difference (FD) method. The results show excellent agreement and the comparison with experimental data validates the model, enabling its use in the design and analysis of MBHEs for which thermal losses are a relevant factor. MBHE effectiveness is defined, and it is shown - for a selected case - that the addition of 5.0 cm thick glass wool raises it by 25.5%.

摘要

提出了一种并流移动床热交换器 (MBHE) 的数学模型。床被稀释并由均匀半径的球体组成，这些球体由活塞流中的拖曳流体输送。气固混合物被烟气间接加热，烟气在 MBHE 周围的夹套中流动。考虑了颗粒内温度梯度和对外部环境的热损失。该模型通过自伴随算子方法 (SAO) 解析求解，并通过有限解析 (FA) 和有限差分 (FD) 方法的组合进行数值求解。结果显示出极好的一致性，并且与实验数据的比较验证了该模型，使其能够用于热损失是相关因素的 MBHE 的设计和分析。MBHE 有效性已定义，