Comparison between random and structured packings for dehumidification of air by lithium chloride solutions in a packed column and their heat and mass transfer correlations

Random and structured packings were compared for their efficiency in dehumidification of air in a packed column using lithium chloride solutions. Experiments were conducted with cross corrugated cellulose and poly(vinyl chloride) (PVC) structured packings, and the results were compared with the data previously obtained for polypropylene Flexi rings and ceramic Berl saddles as random packings. The heat and mass transfer correlations were developed for both random and structured packings that considered the change in driving force due to the change in LiCl concentration. A dimensional analysis of the process variables was carried out using the Buckingham Pi method to obtain the dimensionless groups of the correlations. The data obtained with 5/8 in. polypropylene Flexi rings, 1/2 in. ceramic Berl saddles, and 2 in. clay Raschig rings (data for 2 in. Raschig rings were taken from Bichowsky and Kelley (1935)) were used to test the correlations for random packings. The correlations for structured packings were tested using the data obtained with cross corrugated cellulose and PVC packings. The values predicted by these correlations were within +/- 10% of the experimental data.