Finding limiting flows of batch extractive distillation with interval arithmetic

Heterogeneous extractive batch distillation of chloroform–methanol–water: Feasibility and experiments

“…As all extractive profiles within a given extractive region reach the same stable node, Frits et al (2006) suggest the computing of several extractive profiles displayed in Fig. 3 from the initial charge composition x S0 for different ratio F E /V (0.01, 0.5, 1.0 and 1.2) at infinite reflux.…”

“…Process operation efficiency also depends on the entrainer due to the existence of minimum values for the entrainer flowrate and the reflux ratio. They are both related to the topology of the extractive profile maps, in particular to the univolatility line α A,B =1 and the product composition x P at its intersection point with the edge E -distillate product (A or B) (Knapp and Doherty, 1994;Hilmen, 2000;Steger et al, 2005;Frits et al, 2006).…”

From batch to continuous extractive distillation using thermodynamic insight: Class 1.0–2 with a heavy entrainer

“…The feasibility always rely upon intersection for composition profiles in the various column sections (rectifying, extractive, stripping), joining the top and bottom composition, whatever the operation parameter values (reflux, flow-rates...) [8]. Here we use geometrical analysis but mathematical ones could be used as well.…”

Extractive distillation: recent advances in operation strategies

“…Several achievements have been realized by the use of an algebraic criterion (Levy and Doherty 1986) or mathematical approaches either by using bifurcation theory (Knapp and Doherty 1994), by interval arithmetic (Frits et al 2006), or by a combined bifurcation-shortcut rectification body method (RBM) (Brügge-mann and Marquardt 2008). Extending their method for single-feed azeotropic distillations (Levy et al 1985), Levy and Doherty (1986) proposed an algebraic trial-anderror tangent pinch-point procedure for determining the minimum reflux ratio without the necessity of lengthy iteration schemes involving column profile calculations.…”

“…These authors also published more general diagrams, issued from bifurcation theory, without providing illustrative examples for each. Frits et al (2006) used an interval arithmetic-based branch-and-bound optimizer to find limiting flows based on the existence and location of singular points and separatrices in profile maps and applied it to the same 1.0-1a mixture as Knapp and Doherty (acetone-methanol-water), but for BED. Agreeing with the findings of Knapp and Doherty (1994), they found Brought to you by | Carleton University OCUL Authenticated Download Date | 6/15/15 4:00 AM a feasible process under the infinite reflux ratio above a minimal entrainer-feed flow rate ratio, which corresponded to the merging of a stable pinch point originating from the azeotrope, with a saddle point originating from a pure component.…”