A new method for tieline calculations in binary fluid systems

Haseeb A., KESKİN M. , Pegg I., Meijer P.

FLUID PHASE EQUILIBRIA, vol.120, pp.93-105, 1996 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 120
  • Publication Date: 1996
  • Doi Number: 10.1016/0378-3812(95)02978-8
  • Title of Journal : FLUID PHASE EQUILIBRIA
  • Page Numbers: pp.93-105


We describe a method to determine tielines for a mixture with a given volume V-t and a given mole fraction x(t) at fixed temperature, which is based on the orientation of the tangent plane to the Helmholtz free energy surface. The method works equally well for gas-liquid separation as for liquid-liquid separation. The method is based on a rotation in coordinate space followed by a rotation in function space which establishes the correct direction and the end points of the tieline, The mathematics is described and the general outline of a computer program to implement the method is given, This is followed by an application to a special form of the van der Waals equation, which describes the influence of chain-molecules as proposed by Tompa. The example given shows a three phase separation and the influence of the chain-length thereupon.