Experimental Study of Simultaneous Heat and Mass Transfer in Falling Film and Bubble Mode (LiCl) Absorbers


The study involves lithium-Chloride absorption process for the falling film andbubble columns absorbers, working at the same operating conditions. The resultsobtained were used to analyze the transfer process during the absorption of watervapor in the aqueous solution of LiCl.The performance of both absorbers was investigated for various solution flow rates(0.1-0.5)kg/min , various gas flow rates (1-9) lit/min and inlet solution concentration(40-50) wt% . Results showed that bubble absorber is superior to the falling filmmode for mass and heat transfer and that the efficiency of bubble columns is morethan that of falling film absorbers. Increasing the solution flow rates rarely affectedthe mass transfer, but improved the heat transfer. To evaluate the performance ofmass and heat transfer, experimental results obtained were plotted as Nusselt andSherwood number versus operating conditions respectively for falling film andbubble modes. A power law correlations were obtained for the objective functions(i.e., mass and heat transfer coefficients ) with correlation coefficient between (0.91and 0.97) .