Dehydration of alcohols using osmotic concentration—Dehydration of aqueous glycerol solution

Osmotic concentration (OC) may be used for dehydration of alcohols. In this research OC was employed for dehydration of glycerol using GVHP (Commercially available Millipore hydrophobic poly vinylidene fluoride) membrane for a wide range of glycerol and water (50–99 wt%) mixtures. Triethylene glycol was employed as strip for absorbing water. The operating temperature was changed between 20 °C and 60 °C. MultiSimplex Lite software was utilized to elucidate the influence of temperature and feed concentration on the flux of water. It was found that permeation characteristics depend on the feed concentration and temperature. Results showed that the mass flux increases by increasing the water fractional pressure in the feed side. The permeation rate significantly increases and the selectivity decreases with increasing the temperature.The optimum conditions for higher mass flux are 44 °C using a solvent containing 45% glycerol. Furthermore for glycerol process at temperatures higher than 55 °C, negative mass fluxes were observed due to an increase in the membrane permeability for strip solution.