Parameter study on the adsorptive drying of isopropanol in a fixed bed adsorber

• Adsorption isotherms and BTCs of water from isopropanol on zeolites were determined.
• Dynamic simulations of the BTCs are in good agreement with the experimental data.
• 3A zeolite shows superior drying performance.
• Surface diffusion was found as dominant mechanism of mass transfer.
• Pore diffusivities in type A zeolites depend on adsorptive concentration.

This work focuses on the influence of process parameters on the dynamics of adsorptive water removal from polar organic solvents in a fixed bed adsorber. As a model solvent isopropanol with water concentrations between 5 and 4000 ppmw was used. In a first step equilibrium loadings on 3A and 4A zeolites were determined by shaker bottle experiments. The results were fitted to the Langmuir equation. In a second step fixed bed experiments were carried out in order to characterize the dynamic behavior of the adsorption process. In these experiments 3A zeolite shows a better drying performance than 4A zeolite. The breakthrough curves (BTC) could be well described by dynamic simulations using a set of differential equations for the mass balances and a linear driving force approach (LDF) for the kinetics. Pore diffusivities in the order of 10−12 m2/s were obtained by the simulation, indicating that surface diffusion in the pores of the zeolites is the predominant mechanism of mass transfer.