Computer Simulation of Module Performance

An advanced simulation program based on a phenomenological/semiemprical approach in the pervaporation dehydration of solvents has been developed. This has been done to verify the actual and theoretical performance of the flat-sheet modules. An ethanol-water mixture was used as a model mixture. Some of the permeation parameters, which are used 

With respect to its design, a plate-and-frame module is characterized by (a) dimensions of the plates, length /unit and width Wunit, (b) height of the feed chaimel, and (c) number of membrane sheets in a unit and number of units making up a module. In this study, two arrangements of the feed channels are considered in a module unit (1) series cormection and (2) parallel connection (Fig. 17.7). 

When a vacuum is applied to the permeate side of the membrane, a driving force and activity gradient can be created across the membrane thickness. Selective pmneation takes place, and then feed flow rate as well as feed composition change through the differential volume. Since the heat of evaporation is supplied from the feed side, the feed temperature falls constantly, and so the flux through the membrane decreases. Thaefote, three different balances over the diffCT-ential volume are taken into account as follows  

The changes in feed flow rate, feed composition, and feed temperature along the z direction can be calculated if the flux and permeate composition are expressed as a function of both 

feed composition, and permeate composition should be expressed as a function of location along with z direction. 

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