Direct contact membrane distillation of sugar aqueous solutions

Results are given from direct contact membrane distillation, using tangential flows to the membrane, with sugar aqueous solutions. Several effects on the distillation process are examined: flow rate through the cell, nature of the feed solutions, initial concentrations of the feed solutions, average temperature, and temperature difference. On the basis of enthalpy flux conservation in the different regions, various systems of equations are proposed for the estimation of the interfacial temperatures. Based on the known temperatures of the liquid-vapor interfaces, the experimental distillate fluxes for several sets are fitted to the gas stagnant film diffusion model to obtain the effective diffusion coefficients of the water vapor-air mixture, D-ef, and the results are analyzed.