An optimal control approach to steam distillation of essential oils from aromatic plants. (2nd September 2018)

• Record Type: Journal Article
• Authors: Valderrama, F.; Ruiz, F.
• Is Part Of: Computers & chemical engineering. Volume 117(2018)
• Page Start: 25
• Page End: 31
• Publication Date: 2018-09-02
• Subjects: Essential oils -- Optimal control -- Nonlinear optimization -- Steam distillation; Chemical engineering -- Data processing -- Periodicals; 660.0285
• DOI: 10.1016/j.compchemeng.2018.05.009
• Languages: English
• ISSNs: 0098-1354

Abstract

Highlights: A novel multi-objective optimal control of oil essentials extraction. Yield maximization and energy reduction are simultaneously attained. Time-variant steam flow trajectories are found as optimal solutions. Optimal solutions change slightly with parameters of the vegetable material. Abstract: In this work, an optimal steam flow trajectory for essential oils extraction from aromatic plants is derived, minimizing energy consumption. A phenomenological dynamic model of the oil extraction process is adopted from literature and a multi-objective optimal control problem is formulated, in order to minimize energy consumption and at the same time maximize the yield of extraction. The resulting optimal control problem is highly non-linear and it is solved by numerical methods. Simulation results are presented for three scenarios: (i) Maximum yield, (ii) minimum energy consumption and (iii) trade-off between yield and energy. It is shown that the optimal steam flow rate trajectory is not necessarily constant. Using a mixed cost-function, it is possible to extract almost 100% of oil essential while saving 60% of energy. Finally, a sensitivity analysis shows that the optimal steam trajectory has few variations when parameters of the plant physiology change.