Determination of holdup by air purge in 50 mm discs and doughnuts pulsed extraction column
The characteristics of the time-averaged frictional pressure drop in single-phase flow, which was determined by the air purge method, for the HNO_3 solution and 30% TRPO-Kerosene solution through a 50mm-diameter discs and doughnuts pulsed extraction column were studied firstly.Experimental results showed that the time-averaged frictional pressure drop could be neglected at the condition of A′ω≠0 and (u_c=0), but Noh’s linear relation to u_c at A′ω=0 was satisfied.The frictional pressure drop could be estimated by Noh’s model at A′ω≠0, which was improved for the discs and doughnuts pulsed extraction column.The values predicted by the model were in good agreement with those obtained by experiments.Then the time averaged frictional pressure drop in two-phase flow and the dispersed phase holdup in the column, for the HNO_3 solution and 30% TRPO-Kerosene solution were studied.Experimental results showed that Noh’s model, which was developed for the reciprocating plate extraction column could be used for estimating the dispersed phase hold-up in a discs and doughnuts pulsed extraction column. Here, it was stressed that in the model, the two-phase time averaged frictional pressure drop, (Δp)_f, could be predicted by the equation for the single-phase flow that is the corresponding continuous phase in the two-phase flow.(