Separation and Purification Technology, Vol.145, 39-49, 2015
Experimental and theoretical study on the adsorptive drying of primary alcohols in a fixed bed adsorber
In this paper systematic investigations on the adsorptive drying of primary alcohols from methanol to 1-hexanol on 3A and 4A zeolites are presented. The focus of the work is laid on the superdrying of these polar solvents in the ppm(w)-region. In addition to equilibrium data gained in shaker bottle experiments information regarding the dynamic drying behavior was obtained by breakthrough experiments. The water content in these experiments was monitored online by a transmission photometer. Based on the experimental data a physical model was developed in order to predict the dynamic drying behavior in a fixed bed adsorber. Most of the investigated systems could be well described by this model. Furthermore pore diffusivities of water could be obtained by fitting the model to the experimental data. The results of this study reveal a clear dependency of the dynamic drying behavior of primary alcohols from the solvent to be dried and the type of zeolite. Small alcohol molecules show significantly faster drying rates than long-chain alcohols and the drying kinetics on a 3A zeolite is much faster than on a 4A zeolite. The experimental results were correlated to the molecular dimensions of adsorptives and the size of the pore openings of the zeolites as well as to the interactions between adsorptive, solvent and adsorbent. (C) 2015 Elsevier B.V. All rights reserved.