POWER CONSUMPTION IN A RECIPROCATING PLATE EXTRACTION COLUMN.

Power consumption in a 150 mm diameter Karr reciprocating plate column has been determined by two different but consistent methods, namely force-displacement diagrams at moderate velocities of oscillation and a wattmeter technique at high velocities. The accuracy of the methods is estimated to be plus or minus 10%. Amplitudes in the range 3. 17 to 12. 7 mm and frequencies from 0. 5 to 6. 9 Hz have been investigated for stainless-steel plates with hole size 14. 3 and 7. 50 mm and free area between 13 and 53% and for disc plates. The liquid phase was water in all experiments. It was found that the time average power consumption calculated from the simple quasi-steady state model fitted the data reasonably well at low frequencies and high amplitudes. At high frequencies and low amplitudes the time-averaged power consumption exceeded the quasi-steady state model prediction significantly. Departures from the quasi-steady model are characterized in terms of a Strouhal number relating amplitude, hole size and fraction open area, and a reduced frequency.