Modeling of thermal conductivity of charcoal-nitrogen adsorption beds

A knowledge of the effective thermal conductivity of an adsorption compress or bed is necessary for the design of thermal compressors of adsorption-bas ed coolers. Three existing models have been adopted to compute the effectiv e thermal conductivity considering the adsorbent particles to be porous bod ies. Although the models are tested for an activated charcoal-nitrogen syst em, the calculation scheme can be used for any adsorbent adsorbate pair. Ex perimental isotherm data are used to calculate the equilibrium concentratio n of nitrogen in charcoal. This calculation scheme has been Validated by ex perimental thermal conductivity measurements covering the range 300-400 K a t 1 atm and 100-1000 mbar at 300 K. The calculation scheme based on the Lui kov et al. model is found to be the most successful. An empirical correlati on is proposed to describe the dependence of effective thermal conductivity on the packing density and temperature. (C) 2000 Elsevier Science Ltd. All rights reserved.