Multiresponse optimization based on the desirability function for a pervaporation process for producing anhydrous ethanol

A pervaporation process for producing anhydrous ethanol from industrial ethyl alcohol (95% v/v) was performed with a commercial PVA/PAN membrane. A central composite rotatable experimental design together with response surface methodology was implemented for studying and modeling the influence of operating conditions in terms of the temperature and the flow rate of the feed on the pervaporation performance, namely, the permeate flux and the separation factor. To obtain a trade-off between the permeate flux and the separation factor, a method for simultaneous optimization of multiple responses based on an overall desirability function was used. The optimization resulted in a feed temperature of 66 degrees C and a feed flow rate of 42 L/h. These operating conditions are expected to respond with a permeate flux of 0.107 kg/m(2)h and a separation factor of 40, which correspond to a satisfactory overall desirability.