Effect of Chemical Heterogeneity on Linear Adsorbed Solute Dispersion in fixed Bed.

Abstract: The paper aims at investigating the importance of including chemical heterogeneity in fixed bed as it has been found to induce additional dispersion. A discrete chemical heterogeneity distribution has been considered in the one-dimensional advective-dispersive equation. The partial differential equation was solved using finite volumes method based on the Adam-Bashforth algorithm. Increased dispersion was estimated comparing breakthrough curves second order moments keeping identical hydrodynamic properties as well as medium global capacity. In the objective to prove the presence of chemical heterogeneity effect, we study in the first the transport in homogeneous and chemically heterogeneous medium without hydrodynamic dispersion. Then effect of medium capacity on linear adsorbed solute dispersion into chemically heterogeneous at constant bed length and at the same chemical heterogeneity distribution was investigated. After that, different distributions were considered at different bed lengths too. Effect of chemical heterogeneity was found has nonregular behavior with the medium size but depending on the distribution type though a constant mean value of the distribution. As a result, dispersion increase due to chemical heterogeneity witch depends essentially on the column size and on the nature of heterogeneity distribution causing dependence of the breakpoint time on both. [Copyright &y& Elsevier]