Abstract
Tests have been performed on the modified oscillating baffle contactor (O. B. C.) in which different types of perforated baffles have been introduced, and the results obtained analysed. Two liquid systems have been studied. The systems carbon tetrachloride-acetic acid-water and Methyl ISO-butyl ketone (MIBK)-acetic acid-water were chosen partly from expediency and partly from their suitability and for comparison purpose with published data. Flammable and highly toxic materials were not possible due to prevailing laboratory conditions. Runs made with MIBK were limited strictly for safety and health reasons. Equilibrium data obtained in our laboratory has been extended and equations describing the equilibrium distribution of the systems have been established with high degree of accuracy and compares favourably with published data. For the true performance of the extractor detailed knowledge of the drop size and distribution was necessary. Some high speed cine-film of the drops in the column were taken and analysed. Hold up values of the dispersed phase measured by both the drainage and mano-meteric methods were recorded. The longitudinal dispersion (axial mixing) which occurs in both phases has been examined with the aid of dye injection technique, and the coefficients calculated from Peclet numbers based on the length of the extractor. The relationship between the true, measured and piston flow values of N. T. U. are established. Equations have been developed based on a modification of Rod's method, to predict the true concentration profile of the dispersed phase corresponding to that of the continuous phase along the column. Relationship existing between H. T. U. values and ka values have been presented graphically to explain the extractor performance. Equations to determine sectional values of transfer units and axial mixing have been derived. Data for power dissipated in the contactor have been obtained: by using highly sensitive torque - transducers and recorders. These have been treated both by dimensional analysis and modified existing correlations. Interfacial tension measurements were made for both systems. The, accuracy of these measurements have been found reasonable. They give the magnitude of the change in interfacial tensions with concentration. The measured efficiency of an experimental R. D. C. has been investigated for the purpose of comparison with the O. B. C. for the system CCL 4 - water - acetic acid. The. drop size distributions resulting from the measurement in the 2'6" long O. B. C. is correlated by two equations, which correlate the data with a maximum deviation of +/- 5%. The development was used to predict the interfacial area in the 4' column and hence calculate k values.