The purpose of this paper is to extend the research given in an earlier paper (Stojkovic et al. ), from binary to the ternary mixture case. From the aspect of the optimal control of the operation, the separation of a ternary mixture of hydrocarbons, namely cyclohexane-heptane-toluene, has been researched in depth by many authors (Domenech and Enj,albert 2 ; Nad and Speiegel 3 ; Farhat et al. ; Farhat ; Farhat et al. , Ceylan and Özgen 7 , Bonny 8 , Bonny ). For a binary mixture of cyclohexane-toluene, Mujtaba and Miladi examined the influence of the total number of trays. In general, the increased number of trays reduced the total batch time and reflux ratio. For a specific case, they found that increasing the total number of plates six times decreased the reflux ratio by 13.85% and the total batch time by 45.63%.