A mixture of ethanol and benzene is separated in a network of distillation and membrane separation steps. In one intermediate step, a near-azeotropic liquid mixture of 8,000 kg/h of 23 wt% ethanol in benzene is fed to a pervaporation membrane consisting of a thin ionomeric film of perfluorosulfonic acid polymer cast on a porous Teflon support. The membrane is selective for ethanol such that the vapor permeate contains 60 wt% ethanol, while the non-permeate liquid contains 90 wt% benzene.
(a) Draw a flow diagram of the pervaporation step using the appropriate symbol from Table 1.2 and include on the diagram all of the given information.
(b) Compute the component flow rates in kg/h in the feed stream and in the two product streams and enter these results on the diagram.
(c) What separation operation could be used to further purify the vaporpermeate?
