Absorption of water vapour into lithium bromide-based solutions with additives using a simple stagnant pool absorber

Absorption of water vapour into the 50 mass % lithium bromide solution with four eight-carbon alcohol additives such as n-octanol, 2-octanol, 3-octano l, and 2-ehtyl-1-hexanol were investigated by using a simple stagnant pool absorber, Four solutions of the 60 mass % lithium bromide + water, 68 mass % lithium bromide + ethylene glycol + water (LiBr/HO(CH2)(2)OH = 4.5 by mas s), 60 mass % lithium bromide + lithium iodide + water (LiBr/Lil = 4 by mol e), and 70 mass % lithium bromide + zinc chloride + water (LiBr/ZnCl2 = 1 b y mass) containing the 2-ethyl-1-hexanol additive were also considered to e xamine the additive effect on mass transfer of water vapour into the differ ent types of absorbents. The experimental apparatus could be used with good confidence and accuracy particularly for studying mass transfer enhancemen t over the effective range of additive concentration which, in this work, i s mostly between 10 and 500 ppm. A vigorous interfacial turbulence was obse rved during absorption process using additives. The water vapour absorption rate remarkably increased with increasing the additive concentrations up t o about 200 ppm and then stopped increasing above 200 ppm for all the syste ms considered. The onset additive concentrations for enhancing mass transfe r were located between 5 and 8 ppm for all systems except two systems of th e 50 mass % lithium bromide solution with 3-octanol and 70 mass % lithium b romide + zinc chloride solution with 2-ethtyl-1-hexanol for which the corre sponding concentrations were 2.5 and 35 ppm, respectively. (C) 1999 Elsevie r Science Ltd and IIR. All rights reserved.