Fluid-to-Particle Heat Transfer in Fluidized Beds S i r : When Dr. Rowe's eq 1 is corrected for his errors, it should read
longer random numbers since they were proven to be following a certain definite pattern in a simple rectangular plot of hfsvs. Gf (Rowe, 1974).
Literature Cited No wonder he could not deduce our values from the data presented in Table II! It was needless to say that our raw data were first plotted as h f , vs. Gf and found to be independent of G f . Bradshaw and Myers (1963), Chang and Wen (1966), and Balakrishnan and Pei (1974, 1975) also had similar observations and used the same dimensionless groups. Admittedly the range of our data was quite short, as pointed out by Dr. Rowe. However, it'is very gratifying to note that other workers (Balakrishnan and Pei, 1974; 1975) have subsequently extended the experimental range to 0.02 < Ar/Re,,2 < 10.0 and vindicated our results. Dr. Fbwe would be glad to notice that our data were no
Balakrishnan, A. R., Pei, D. C. T., Paper 24a presented at 24th Canadian Chemical Engineering Conference, Ottawa, Oct (1974). Balakrishnan. A . R.. Pei, D. C. T., Can. J. Chern. Eng., in press (1975). Bradshaw, R. D., Myers, J. E., A . I . C h . E . J., 9, 590 (1963). Chang, T. M., Wen, C. Y . , Chem. Eng. Progr. Symp. Ser., 62, 111 (1966). Rowe, P. N . , Chem. Techno/.,4, 9 (1974).
Department of Chemical Engineering McGill University Montreal, Canada
Dilip Bhattacharyya*
Department of Chemical Engineering University of Waterloo Waterloo, Canada
David C. T. Pei
LETTER TO THE EDITOR
Measurement of Concentrations near an Interface during Liquid-Liquid Mass Transfer Sir: We wish to call attention to a recently discovered systematic error that influenced the results presented in the paper by Traher and Kirwan (1973). In that paper was reported a significant interfacial resistance during the transfer of acetone from carbon tetrachloride to water. We have since determined that this conclusion is faulty apparently because the microscope slides that were employed in the interferometer departed significantly from flatness. We have recently repeated the experiments with optically flat glass in the microinterferometer and found that interfacial equilibrium was obtained after no more than 10 sec of contact. This conclusion was observed when acetone was transferred from CCl4 to H2O or from H20 to CC14 and regard-
less .of the presence of the surfactants, sodium dodecyl or sodium tetradecyl sulfate. We regret any inconvenience we may have caused a reader who accepted our results. We would also like to note that the main point of the original paper-that the microinterferometric method does allow rapid measurements of concentrations near an interfaceis valid.
Literature Cited Traher. A.. Kirwan, D. J., Ind. Eng. Chern., Fundarn., 12, 244 (1973).
Department of Chemical Engineering University of Virginia Charlottesuille, Virginia 22901
B. A. Bogue A. Myerson D. J. Kirwan'
Corrections Equilibrium Properties for Gas Mixtures on Homogeneous Solid Surfaces from a Statistical Mechanical Model for Partially Mobile Adsorption In this article by C. S. Lee and J. P. O'Connell [Znd.Eng. Chem., Fundam., 13, 165 (1974)] the quantity B H , ~ appeared in eq 26 but was undefined. I t is OHLJ
TPsCH,~ 2/4
where the other symbols are all defined. Also the quantity Ri, should be R1. Equation 27 has the quantity 8. R A , , which ~ should be 2R~,,8,/0. 8
Thermodynamics of Multicomponent Liquid Mixtures Containing Subcritical and Supercritical Components In this article by D. S. Abrams, F. Seneci, P. L. Chueh, and J. M. Prausnitz [Znd, Eng. Chem., Fundam., 14, 52 (1975)l in the paragraph following eq 2, lines 4 and 5 were printed incorrectly. The following definitions should have 282
Ind. Eng. Chem., Fundam., Vol. 14, No. 3, 1975
been printed: 0 = partial molar volume in the liquid Y ~ ( S F ) = activity coefficient of i in the solute-free mixture a t T and zero pressure.
