Dynamics of intraparticle desorption and chemical reaction in fixed-beds using inert core spherical particles

Abstract

The effect of chemical reaction on the desorption dynamics of a fixed-bed packed with inert core/hollow monodisperse spherical rigid particles were studied. We modeled the reactive desorption system with both linear and nonlinear mass exchange laws between the moving and the stationary phases. The governing equations were integrated numerically using finite difference method. The numerical solution was validated by comparison of the results with those of a previously published analytical solution. Effects of the Thiele modulus on the behavior of the breakthrough curves in presence of chemical reaction were investigated. The numerical results of the mathematical modeling reveal that the effects of the Thiele modulus on desorption are not important for Thiele moduli greater than 10. Further, for wide ranges of the Thiele moduli the linear exchange law leads to better results for desorption enhancement because of chemical reaction, compared with those of Langmuir isotherm. Incorporation of the nonlinear Langmuir exchange law in the model equations demonstrates a larger mass transfer resistance. Use of large values of the Thiele modulus hardly show any difference between the performance of the reactive desorption bed for linear and nonlinear isotherms, however, small values of the Thiele modulus leads to 30–35% less mass exchange for the nonlinearity effects. These results call for a longer bed when the nonlinear isotherm is used.