Distillation design/optimization

Optimization. Optimi2ation of the design variables is an important yet often neglected step in the design of extractive distillation sequences. The cost of the solvent recovery (qv) step affects the optimi2ation and thus must also be included. Optimi2ation not only yields the most efficient extractive distillation design, it is also a prerequisite for vaUd comparisons with other separation sequences and methods. 

Extractive Distillation Design and Optimization Extractive distillation column composition profiles have a veiy characteristic... 

Diwekar UM (1995) Batch Distillation - Simulation, Optimal Design and Control, Taylor Francis. 

I. M. Mujtaba, 2004, Batch Distillation Design and Operation, Imperial College Press, London. I.M. Mujtaba and S. Macchietto, 1993, Optimal operation of multicomponent batch distillation-... 

Ryan, P.J., and M.F. Doherty, Design/Optimization of Ternary Het-ODgeneous Azeouopic Distillation Sequences, AIChE J., 35, 15K-I60I (1989),... 

The two bottoms specifications are the required product purities. The two distillate compositions are design optimization variables to be established by economics. As the distillate specifications get closer and closer to the corresponding azeotropic compositions, the separations in each column become more difficult and more trays are required (higher capital investment). However, the flow rates of the recycle stream D and D2 decrease as the difference between the two distillate compositions increases, so energy consumption... 

The task of designing of extractive distillation columns, besides calculation of section trajectories, includes a number of subtasks. These are the same subtasks as for two-section columns and additional subtasks of determination of minimum entrainer flow rate and of choice of design entrainer flow rate. Optimal designing of extractive or autoextractive distillation includes optimization by two parameters - by entrainer flow rate and by reflux number. Figure 7.14 shows influence of entrainer flow rate on section trajectories at fixed value of parameter a = LfV)mlK j (as is shown in Section 6.4 (L/y) = K j). 

Formulation of process and control design optimization for the binary Distillation Example... 

Ryan P. J. and M. F. Doherty, Design/optimization of ternary heterogeneous azeotropic distillation systems, A/CliE y., 35, 1592-1601 (1989). 

Despite the advances in the thermodynamics for predicting azeotropic mixture, feasible distillation boundaries, and sequence of cuts, the azeotropic batch distillation system is still incipient in terms of design, optimization, and optimal control. 

U. Diwekar. Batch Distillation Simxdation, Optimal Design, and Control. CRC Press, Boca Raton, 2nd edition, 2012. 

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