Dimensionless mass-transfer correlations for packed-bed liquid-desiccant contactors

Random and structured packings were studied with varying bed depths in the regenerator and the dehumidifier of a solar-assisted liquid-desiccant system. The slopes of the log-log plots of mass-transfer rate vs solution flow rate were found to be close to 0.8, which indicated that the conditions for the liquid phase were turbulent for the operating conditions in both contactors. The small intercepts obtained for the Wilson plots indicated that the gas-phase mass-transfer resistance was negligible compared to the liquid-phase mass-transfer resistance. Liquid-phase mass-transfer coefficients for the packed bed alone were obtained by separating the contributions of the other mass-transfer regions in the contactors. The random packing mass transfer coefficients varied from 0.48 to 2 mol/(s m(2)), while the double-layer, structured packing mass-transfer coefficients varied from 0.018 to 0.035 mol/(s m(2)). These mass-transfer coefficients were converted into a dimensionless form, utilizing experimentally obtained diffusivity values.