Mass transfer in a pulsed column

An analogy between mass and momentum transfer for pulsed flow was developed for predicting mass transfer coefficients. The method applies for mass transfer from the wall to a fluid in pulsed flow in a circular tube. Two dimensionless groups, @ = WA/H and or1 = R(up/p)1/2, are needed to represent the effect of pulsation on the mass transfer coefficient. For a known system of tube and fluid, the information required to use the method are the frequency and amplitude of the pulse. Experimental data were obtained for steady and pulsed flow by measuring the rate of solution of /3-naphthol into water in a 2 in. I.D. tube from Nae = 0 to 11,000. The theoretical equation, which contains no arbitrary constants, predicts the experimental results with an average deviation of 11 per cent. Increases in both frequency and amplitude of the pulse improve the mass transfer coefficient. The increase due to pulsation is significant at all Nm in the streamline flow region. In turbulent flow this is not the case, and at NW = 11,000 no effect was observed at frequencies up to 50 c/mm. The beneficial effect of pulsed flow on mass transfer has been studied particularly in liquid-liquid extraction apparatus.