Numerical modelling of microwave heating of a porous catalyst bed
Numerical modelling of microwave heating of a porous catalyst bed
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DOI：
10.1080/08327823.2019.1569900
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发表时间：
2019-01
影响因子：
1.5
通讯作者：
P. Muley;K. Nandakumar;D. Boldor
中科院分区：
文献类型：
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作者：
P. Muley;K. Nandakumar;D. Boldor
摘要利用COMSOL Multiphysics软件建立了微波反应器（2450 MHz）内催化剂床层的多物理场数值模型，研究了催化剂床层的尺寸、形状和位置对微波反应器的影响。在25 °C至370 °C范围内的9个不同温度和不同频率下测量了HZSM-5催化剂的介电性质。通过从电磁学中提取传热问题的热源项Q，将多孔介质中的传热问题与射频电磁学模块和流过多孔介质耦合起来。固体-流体热非平衡条件被建模为催化剂内产生的热量。据观察，样品的位置、形状和尺寸都显著影响多孔介质内的加热曲线和温度梯度。实验结果与预测值吻合较好。微波加热具有较高的总内能，而常规加热在达到稳态后具有较低的温度梯度。砖形样品比圆柱形样品加热更均匀。如果样品的半径减小，同时保持样品的体积，微波会穿透样品内部更深，并且在样品的整个长度上观察到更均匀的温度分布。
Abstract A Multiphysics numerical model was developed using COMSOL Multiphysics to study the effect of size, shape and position of catalyst bed within the microwave reactor (2450 MHz). The dielectric properties of HZSM-5 catalyst were measured at different frequencies and nine different temperatures ranging from 25 °C to 370 °C. The heat transfer in porous media was coupled with RF electromagnetics module and flow-through porous media by extracting the heat source term Q for the heat transfer problem from the electromagnetics. A solid-fluid thermal non-equilibrium condition was modelled as the heat is generated within the catalyst. It was observed that sample position, shape and size of the sample, all significantly affect the heating profile and temperature gradient inside the porous media. The experimental results and the predicted temperatures were in good agreement. Microwave heating had higher total internal energy but conventional heating had lower temperature gradient after reaching steady state. Brick-shaped sample heats more uniformly compared to cylindrical sample. If the radius of the sample is decreased, while maintaining the volume of the sample, microwaves penetrate deeper inside the sample, and more uniform temperature distribution is observed throughout the length of the sample.