Adsorption isotherms of CFC-113 on activated carbon were determined at various temperature (298K, 313K, 343K, 373K, 393K)up to 40 torr. The isotherms were predicted by Langmuir, LRC models fairly well. Fixed bed adsorption experiments were performed with varing flow rate, concentration and temperature. A nonequilibrium, nonadiabatic model with thermal equilibrium between adsorbent and gas phase was used to simulate experimental breakthrough data. Mass transfer coefficients were estimated by matching constant pattern solution with experimental breakthrough curves. Mass transfer coefficient determined in this way, predicted experimental breakthrough times and breakthrough curves well.
Mass transfer coefficients were significantly affected by temperature but not by concentration, flow rate. This results revealed surface diffusion is dominant mass transfer mechanism. Therefore, simmulating desorption breakthrough data, variation of mass transfer coefficients with temperature were accounted. Fixed bed desorption experiments were made with varing purge temperature and flow rate. Increasing purge temperature, roll up values were enlarged and desorption times were shortened. Increasing purge flow rate, desorption times were shortened with minor change in roll up values. These behaviors were successfully simulated by model. Both experimental and simulating results revealed optimum purge flow rate and temperature exist. The effects of adsorption pressure and feed concentration on desorption breakthrough curves were studied by simulation. Cycilc operations were performed changing adsorption flow rate, purge flow rate and temperature. Experimental results showed higher feed to purge ratio is possible at high purge temperature.
