Heat Transfer in a Fixed Bed Elliptic-Cylindrical Reactor: A Pseudo-Homogeneous Model with First-Order Chemical Reaction Term

Abstract

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,