Three phase flash calculations using free energy minimisation

✍ Scribed by M.E. Soares; A.G. Medina; C. McDermott; N. Ashton

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 502 KB
• Volume: 37
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(82)80114-0

✦ Synopsis

Abslnct-The distillation of systems exhibiting partial miscibility over part of the composition range is growing in interest and the modeling of three phase distillation columns is highly desirable.

This paper presents work which has been produced as part of a project directed towards such objective.

An algorithm for flash calculations in which partially miscible systems are involved is described. The algorithm is based on the principle of minimisation of the system Gibbs free energy which is becoming increasingly popular allowing as it does for the simultaneous satisfaction of the constraints of equilibria and mass balance requirements. The minimisation procedure is based on a Newton-Baphson algorithm and so in order to avoid trivial solutions it is necessary to have an adequate choice of initial conditions.

In the present paper this is taken into due account and a policy for selecting initial compositions and flowrates is presented.

Numerical examoles are aresented for the ternary systems ethanol/ethylacetate/water and methanollethylacetate/water.