Design and control of a complete heterogeneous azeotropic distillation column system

Abstract

In this work, design and control of a complete heterogeneous azeotropic distillation column system of isopropyl alcohol (IPA) + water (H 2 O) with cyclohexane (CyH) as an entrainer is investigated. There are two feasible approaches to design the complete flowsheet for the separation of IPA and H 2 O. One approach is to use total of three columns, another simpler design is to only use two columns. From TAC (Total Annual Cost) analysis, the simpler approach is more economical. The suitable control strategy for this complete heterogeneous azeotropic distillation column system is also studied in this paper. From process analysis and dynamic simulation, the overall control strategy is developed which requires two temperature loops in the first column and one temperature loop in the second column. The overall control strategy is tested with composition and flow rate variations in the fresh feed stream. The specifications of the IPA product and waste water composition are all met despite of the various disturbances