Ethanol mass transfer model of spiral-wound membrane module with PDMS membrane for pervaporation considering module structure parameters

•Ethanol mass transfer model of spiral-wound membrane module for pervaporation.•Model was verified by experimental results with correlation coefficient of 0.998.•Mass transfer coefficient and local ethanol flux decreased along the flow direction.•Membrane module structure and operation parameters affect membrane flux. Pervaporation mass transfer model of spiral-wound membrane module with polydimethylsiloxane (PDMS) membrane considering module structure parameters has been developed for ethanol separation. Membrane intrinsic parameters involved mass transfer including limiting diffusivity of ethanol, plasticization coefficient of ethanol and partition coefficient were firstly determined, and then the model was verified by the experimental results with a correlation coefficient of 0.998. It has been calculated that bulk ethanol concentration (xe) would be decreased from 9 v/v% to 7.26 v/v% along the flow direction, under the ethanol feeding concentration of 9 v/v%, feeding velocity of 0.008 ms−1, membrane length of 1 m, membrane width of 1.5 m, channel height of 1.2 mm, if polydimethylsiloxane/polyamide (PDMS/PA) membrane was applied. Owing to the concentration-dependence of the membrane mass transfer coefficient (km), km and local ethanol flux (Je) was also decreased from 7.20 × 10-6 m·s-1to 7.07 × 10-6 m·s−1, and 386 g·m−2·h−1 to 306 g·m−2·h−1, respectively. For polydimethylsiloxane/polyvinylidene difluoride/Polyethylene terephthalate (PDMS/PVDF/PET) membrane, km and Je were decreased from 7.72 × 10-7 m·s-1to 7.65 × 10-7 m·s−1, and 137 g·m−2·h-1to 128 g·m−2·h−1, respectively, under the same condition. Higher ethanol feeding concentration and longer module would lead to more obvious change in xe, km and Je. While higher feeding velocity would lead to weaker change in xe, km and Je.