Benzene adsorption and hot purge regeneration in activated carbon beds

Experimental and theoretical studies were performed on adsorption of benzene from nitrogen gas stream and thermal regeneration by hot nitrogen purge, in fixed beds charged with activated carbon. System temperature and effluent concentration data were collected during adsorption-regeneration runs. A mathematical model was developed to simulate temperature and concentration data of adsorption and regeneration. The model developed was based on non-equilibrium, non-isothermal and non-adiabatic conditions. Three heat transfer resistances were considered in interfaces of gas-solid, gas-wall, and wall-atmosphere. A linear driving force mass transfer model with a variable lumped-resistances coefficient was found to provide an acceptable fit to the experimental data. Experimental and modelling results were used to study the effects of adiabatic and non-adiabatic operations, contact time, gas velocity, regeneration temperature and initial bed loading on the regeneration efficiency. Besides, the specific energy requirement and purge gas consumption were evaluated to discuss the process efficiency. (C) 2000 Elsevier Science Ltd. All rights reserved.