Effect of Surfactant on Water Vapor Absorption into Aqueous Lithium Bromide

Abstract

The objective of the present study is to investigate the absorbing characteristics of water vapor in LiBr-H2O (weak solution) and also the enhancement of absorption in presence of a surfactant in the absorber of a vapor absorption refrigeration system. It reveals from literature that the rate of absorption enhances for marangoni convection occurs due to inclusion of surfactant in the weak solution. An experimental setup for testing the effect of surfactant on the absorption of water vapor in LiBr-H2O solution in a Vapor Absorption Refrigeration (VAR) system is designed and constructed. The experiments were performed with four different concentrations of LiBr such as 45%, 50%, 55% and 60% in LiBr-H2O solution by weight and three different surfactant concentrations such as 100, 200 and 300 ppm in the weak solution. 2-ethyl-l-hexanol was used as surfactant in this experiment. From the experimental results it can be said that, the absorption of water is found to increase with the increase of concentration of LiBr in the weak solution of LiBr-H2O.The addition of surfactant enhances the absorption of water vapor. The maximum enhancement of water vapor absorption is obtained when surfactant concentration is 300 ppm and LiBr concentration is 50% in LiBr-H2O weak solution by weight. Also the experimental results agree with the experimental results of Jung [68] et al. and Kim [65] et al. closely (the deviations of enhancement of present work are about 6.3% and 6.6% less than that work of Jung et al. and Kim et al. respectively).