Ethanol and benzene are separated in a network of distillation and membrane separation steps. In one 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 an ionomeric film of Ethanol and benzene are separated in a network of distillation and membrane separation steps. In one 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 an ionomeric film of perfluorosulfonic polymer cast on a Teflon support. The membrane is selective for ethanol, so 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 symbols from Table 1.2, and include all process information.

(b) Compute the component flow rates in kg/h in the feed stream and in the product streams, and enter these results into the diagram.
(c) What operation could be used to purify the vapor permeate?

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Table 1.2 Separation Operations Based on a Barrier Separation Operation Symbol Osmosis (1) Reverse osmosis* (2) Dialysis* (3) Microfiltration (4) Ultrafiltration* (5) Pervaporation* (6) Gas permeation (7) Liquid membrane (8) VIL VIL VIL Initial or Feed Phase Liquid Liquid Liquid Liquid Liquid Liquid Vapor Vapor and/or liquid Separating Agent Nonporous membrane Nonporous membrane with pressure gradient Porous membrane with pressure gradient Microporous membrane with pressure gradient Microporous membrane with pressure gradient Nonporous membrane with pressure gradient Nonporous membrane with pressure gradient Liquid membrane with pressure gradient Industrial Example Desalinization of sea water Recovery of caustic from hemicellulose Removal of bacteria from drinking water Separation of whey from cheese Separation of azeotropic mixtures Hydrogen enrichment Removal of hydrogen sulfide *Design procedures are fairly well accepted. "Single units are shown. Multiple units can be cascaded. Details of examples may be found in Kirk-Othmer Encyclopedia of Chemical Technology, 5th ed., John Wiley & Sons, New York (2004-2007).