Details

The graphical method derived by Hunter and Nash (1) and later by Kinney (2) is used to obtain the number of equilibrium stages required to achieve a particular raffinate specification. This separation is usually difficult to realize with distillation due to the presence of a severe tangent pinch at high compositions of water, which prevents the distillate from being acid-free. A graphical solution performed by hand calculation has been presented by Wankat (3). This problem is solved more easily and accurately using the graphical approach of Hunter and Nash. Equilibrium data at 1 atm and 25°C is given by Wankat and can be used to plot the tie lines.

References

[1] T. G. Hunter and A. W. Nash, "The Application of Physico-Chemical Principles to the Design of Liquid-Liquid Contact Equipment, Part II: Application of Phase-Rule Graphical Method," J. Soc. Chem. Ind., 53, 1934 pp. 95T–102T.

[2] G. F. Kinney, "Leaching Calculations: A Note on the Graphical Method," Ind. Eng. Chem., 34, 1942 pp. 1102–1104.

[3] P. C. Wankat, Equilibrium Staged Separations, New Jersey: Prentice Hall, 1988 (example 18–2, pp. 595, and example 18–3, pp. 609).

[4] H. Binous, "Equilibrium Staged Separations using Matlab® and Mathematica®," Chemical Engineering Education, 42(2), 2008 pp. 69-73.

[5] H. Binous, "Liquid-Liquid Equilibrium and Extraction using Mathematica®," Computers in Education Journal, 16(1), 2006 pp. 78-81.