Transporte de calor em reator cilíndrico elíptico de leito fixo recheado de partículas: modelagem, simulação e otimização.

Abstract

This research has developed a of the three dimensional transient mathematical model in the elliptic cylindrical coordinate system applied to porous bed which describes the temperature distribution inside the one. Every formulation was applied to study the heat transport within the packed bed reactor, using convective boundary condition in the inner and outer walls, heat conduction in the wall of the reactor and variables thermophysical properties. The mathematical model presented can be applied to geometric shape beds varying from rectangular channel to elliptical cylinder including circular cylinder. The three-dimensional numerical solution of equation that describes the problem of heat transport inside a fixed bed reactor with elliptic cylindrical geometry was obtained by using the finite volume method. To discretize the general equation of energy conservation was used the WUDS (Weigthed diference Upstream Scheme) scheme as interpolation function for the diffusive and convective terms and a fully implicit formulation. The linear algebraic equations system, obtained from the discretization of the energy equation at all points of the computational domain is solved iteratively by the Gauss-Seidel method. Results of the temperature distribution inside the reactor at various axial positions along the bed are presented and analyzed. Several process conditions were studied by varying the of convective heat transfer coefficient, dimensions of the reactor, bed porosity, and temperature and superficial velocity of the fluid at the entrance of the system. We conclude that the porosity, superficial velocity and heat transfer convective coefficient are parameters of great importance in the phenomenon of heat transfer in fixed bed reactors.