固定床椭圆-圆柱反应器的传热:一阶化学反应项的拟均匀模型

R. M. da Silva, A. S. Pereira, V. D. de Miranda, J.M. Freitas de Oliveira, A. G. Barbosa de Lima
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引用次数: 0

摘要

本文采用圆柱-椭圆坐标系建立了瞬态三维数学模型,并将热物理性质作为位置或温度的函数。目的是预测一阶化学反应时椭圆-圆柱形固定床反应器的传热,其反应热由幂律给出。采用有限体积法、WUDS插值格式和全隐式方法求解了该现象的控制方程。讨论了不同的反应物浓度、阿伦尼乌斯指数前因子和反应物入口温度对反应的影响。结果表明:低摩尔浓度下一阶反应对温度分布影响不大,而高摩尔浓度(从0.8 kmol/m3开始)使径向温度梯度增大;反应器入口温度的升高有利于设备中心加热区增大,但对径向温度梯度变化不显著;阿瑞尼乌斯指数前因子与反应物浓度在同一数量级上变化,实际上在反应器中产生相同的温度场;
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Heat Transfer in a Fixed Bed Elliptic-Cylindrical Reactor: A Pseudo-Homogeneous Model with First-Order Chemical Reaction Term
In this work a transient three-dimensional mathematical model was developed using cylindrical-elliptic coordinate system and thermo-physical properties as functions of the position or temperature. The aim is to predict heat transfer in an elliptic-cylindrical fixed bed reactor subjected to a chemical reaction of first order whose heat of reaction is given by the power law. The governing equation of the phenomenon is solved using the finite volume method, and the WUDS interpolation scheme, and the fully implicit method. Results are presented and discussed by varying reagent concentration, Arrhenius pre-exponential factor and reagent temperature at the reactor inlet. It was found that: first-order reactions at low molar concentrations have few effect in the temperature distribution and high molar concentrations, from 0.8 kmol/m3, increase the radial temperature gradients; an increase in the inlet temperature of reactor favours the increase in the heating zone in the centre of the equipment, but does not significantly alter the radial temperature gradients; the Arrehnius pre-exponential factor varying in the same order of magnitude as the concentration of reagents practically produces the same field of temperature in the reactor,
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