Modeling of Adsorption Fronts in Supported Ionic Liquids and Validation by Microwave-Based Measurements and Breakthrough Experiments

An important process of chemical engineering is the removal of moisture from natural gas and process gases by fixed-bed adsorption. Experiments were conducted to design (ad)sorption columns, predict breakthrough behavior, and determine the velocity of the (ad)sorption front. The data obtained from these adsorption experiments served as input parameters for modeling by the linear driving force approach. In this study, the supported ionic liquid (SILP) 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO3]), coated on porous silica, was used as drying agent in fixed-bed adsorption. A novel method for the operando monitoring of (ad)sorption fronts in fixed-bed adsorbers is the radio-frequency-based cavity perturbation method. Here, the adsorber forms a cavity resonator. A model based on S-shaped advancing sorption profiles that is represented by a cumulative Gaussian distribution (CDF) is applied. Furthermore, it is shown that the modeled (ad)sorption fronts lead to resonance parameters measured via the microwave-based cavity perturbation method with high precision. It is demonstrated that the breakthrough curves in SILPs can be accurately reproduced both by the new radio-frequency-based method and by a classical chemical engineering tool such as the linear driving force model.