Experimental and numerical investigation of the effect of pellet size on the adsorption characteristics of activated carbon/ethanol

Low temperature adsorption cooling is an attractive heat powered cooling technology suitable for various applications where waste heat is available. The use of activated carbon as adsorbent with ethanol offers potential for low temperature cooling applications like the food retail industry. Activated carbons are commercially available in the form of powders, granules and pellets. Although powder materials have the advantage of good adsorption kinetics but they are difficult to integrate in adsorption beds. Pellets and granules come at various shapes and sizes and can be effectively accommodated in adsorption beds but offer slower kinetics compared to the powder form. This work experimentally and numerically investigates the effect of pellet size on the ethanol adsorption characteristics of Norit RX3 activated carbon. Dynamic vapour sorption (DVS) testing was used for measuring the adsorption isotherms and kinetics for a range of pellet lengths ranging from 3mm to 12mm. COMSOL Multiphysics was used to simulate the adsorption effect taking into account the diffusion process. Results showed that increasing the pellet dimension in terms of diameter and length reduces the adsorption kinetics. © 2014 The Authors. Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ICAE