Cross-flow in pervaporation

S is the Faraday constant (96500 Coulombs/equivalent). q is the flow rate (1/s), Ac the 

The total membrane area required for a certain separation can now be obtained by substitution of equations Vin - 71 and 72 into vm - 69 

The total energy consumption of the process is now given by the contribution of the electrical energy to drive the ionic transfer and by the energy of the pumps to circulate the various solutions (see figure Vin - 36). Generally two or three pumps are required for the concentrated and depleted streams and for the anode- and cathode-rinse solutions. The energy consumption can be calculated from eq. VUI - 78. 

Oiff ion dialysis in another process which operates according to the same principle. In this process protons or hydroxyl ions are removed from an aqueous stream. 

Dialysis is normally operated in a counter-current configuration and a schematic flow scheme is shown in figure Vm - 37. 

---