An optimization of water transport through polyurethane silica-nanocomposite membrane

Analysis of water transport through polyurethane silica nano-composite membranes were performed by numerical simulation and experiment. Simulation work was performed using a finite element analysis (FEA) software, COMSOL Multiphysics. Experimental work was performed to validate the simulation model. Through simulation we suggest the minimum membrane-to-membrane distance for stacked membranes to be 2-mm to avoid the membrane concentration polarization effect. The method used to create a concentration gradient between the membrane feed side (humid air) and the membrane permeate side (connected to vacuum) involved with creating a pressure gradient. Water vapor pressure gradient creates a concentration gradient which drives water vapor molecules to diffuse from the membrane feed side to the membrane permeate side. Different membrane configurations including rectangular parallel membranes, perforated cylinder with circular membranes, perforated group of cylinders with circular membranes, and perforated cylinder with curved rectangular membranes were compared in terms of water vapor removal from humid air while connecting all membrane configurations to 47-mm vacuum port. The parallel 22 membranes exhibited maximum water removal. Based on the total membrane area, water vapor removal was maximized at the maximum membrane effective area in contact with humid area. The maximum total water removal was obtained for the 11 cassettes with 22 rectangular membranes with a value of 142 g/(m(2)center dot s) while the relative humidity dropped from 60% at the duct inlet to 25.6% at the duct outlet.