Moreover, the influence of the initial composition will be investigated. In the very first case above, as noted in Table , the initial composition of the ternary mixture was set to [cyclohexane: 0.1; (n-heptane):0.1; toluene: 0.8], however the set of data will be changed to the case where the first two components are decreased and the third least volatile component is increased (cyclohexane: 0.063; (n-heptane: 0.088; toluene: 0.8490). Fig 1c . shows the optimal control pattern for the initial mixture composition varied. The optimal control structure is a clear "bang-bang" type, which means that it is comprised of bang and zero arcs only, and they are equal in number. There exist 17 commutations between different types of control. Compared to the very first case treated in this paper, this policy is much easier to apply, however, it must be noted that it brings 6.80% less in recovery rate. Similarly, as in previous cases, the influence of two parameters will be investigated as well: initial mixture composition and tray hold-up. Fig 2c . shows the optimal control pattern for both parameters varied: initial mixture composition and tray hold-up. Interestingly, the optimal control structure is of "bang-bang" type too, however, the total number of bang/zero, resp., arcs, more than doubled, as it contains 19 bang/zero, resp., arcs. Consequently, it has 37 switchings between different types of control. When it comes to recovery rate, over the same time horizon it gives somewhat better gains than the previous case, 1.35% more. next to it starts the "bang-bang" type. However, here it has four bang and four zero arcs, being seven switching between different types of control. It is noticed that the first three bang arcs are from the same duration, while the last bang arc is much longer than others, as it takes 0.125 [h] of the total time, which is almost 13 times longer than any other bang arc.