EXAMINATION OF LIQUID-FILM CHARACTERISTICS IN THE PREDICTION OF PRESSURE-DROP IN A VENTURI SCRUBBER

Liquid film characteristics in the prediction of pressure drop in a Ve nturi scrubber was examined by measuring the film flowrate, film thick ness, and pressure drop by varying the injection orifice diameter, the throat gas velocity, and the liquid loading in a pilot-scale unit. Th e liquid mass flowrate flowing on the Venturi walls was found to be re latively independent of orifice diameter and decreased with throat gas velocities. The effect of increased liquid loading decreased the film flow on the orifice side and increased the same on adjacent walls. Th e average thickness of the liquid film on the walls was found to incre ase with orifice diameter on the orifice side, and with axial distance and decrease with orifice diameter on the adjacent-side walls, and th roat gas velocity. The film velocities calculated were found to increa se with throat gas velocity and liquid loading and continuously decrea se along the axial direction. The distribution of the injected liquid flowing on the scrubber walls was found to depend on the liquid to gas ratio, throat gas velocity, liquid film thickness, axial pressure dro p and relative velocity between the liquid film and the adjoining gas stream. An annular flow model, modified to include the variation in li quid film thickness using correlation developed during this work accur ately predicted pressure drops for a wide range of operating condition s compared to the most commonly used models. (C) 1998 Elsevier Science Ltd. All rights reserved.