Liquid-liquid extraction in an oscillating Baffle Column

• Main Author: Mao, T. D.
• Published: University of Surrey 1963
• Subjects: 620
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751594

A new liquid-liquid extractor called the oscillating Baffle Column is described. Its performance at various baffle oscillating speeds both under constant flow ratio and constant throughput runs using the system carbon tetrachloride - acetic acid - water has been investigated. Two simultaneous differential equations for the extract and raffinate phases respectively have been derived, The equations give the relationship between longitudinal mixing and mass convection in a single phase and interfacial mass transfer. By assuming equilibrium distribution to be linear, the change of Ka, the mass transfer coefficient, along the column can be represented by a polynomial. The two simultaneous equations can be solved either by the use of the Airy function' or by Power Series. The Practical applications of the solutions of these equations are limited as they are cumbersome and contain constants difficult to evaluate. A method has been derived for calculating the eddy diffusivity from concentration profile data. The calculation is restricted to the aqueous phase and has been made for a range of operating conditions. The values of the true Noy, and measured Noy, the numbers of transfer units to effect the separation differ by a 'correction term'. This correction term is a measure of the longitudinal mixing and valves for it have been calculated using a method developed. A "dimensionless fractional extraction" diagram is developed. It provides a means of measuring the operating performance of an extractor.