Capability of a falling film microstructured contactor for the separation of binary mixtures

The present study investigates evaporation and separation of a binary mixture of ethanol and n-propanol in a microstructured falling film contactor made from two electrically heated vertical plates grooved with straight microchannels and forming the sides of a common gas chamber. Experiments were performed at atmospheric pressure (101.3 kPa) and various wall temperatures above the saturation temperature of the inlet binary mixture. Electrical heating fluxes ranged from 2 to 4 kW/m(2) and feed flowrate between 1 and 8 g/min. The feed concentration was fixed around 46 mol.% of ethanol. The results indicate that the microcontactor performances depend essentially on heat flux and feed flowrate and provide fundamental insight on critical values of these two factors. Analysis of the results point out that intermittent local dry-zone can occur at high heat flux or at low feed flow rate. This occurrence influences microcontactor performances which can be evaluated in terms of stripping efficiency and power of separation. (C) 2010 Elsevier B.V. All rights reserved.