Modelling the Desorption of Ethanol from an Externally Heated Saturated Activated Carbon Column by Purging with Air

Abstract

The desorption of ethanol from an externally heated column loaded with activated carbon and purged with air has been studied. The column was initially saturated with liquid ethanol. This process simulates the regeneration step in a concentration-swing/thermal-swing adsorption process for the production of fuel-grade ethanol. A theoretical model was developed for describing the mass- and heat-transfer kinetics of the process. Validation of the model was achieved by comparing its predictions with experimental data, employing initial column temperatures between 298 K and 395 K and air flow rates between 1.6 × 10 −6 m 3 /s and 11.3 × 10 −6 m 3 /s. Experimentally measured adsorption isotherms of ethanol from ethanol/air gas mixtures onto activated carbon, as well as the regeneration column dynamics, are reported.