Entrainer Process Flowsheets & Simulations
Explore 3 validated, solved Entrainer simulation flowsheets in MaximaLabs — real components: ethanol, water, n_hexane, acetic_acid, diisobutyl_ketone, emim_bf4. Open any one directly in your browser.
Solved via: NRTL, IONIC-LIQUID.
Heterogeneous azeotropic distillation
An n-hexane entrainer carries water overhead as a ternary heteroazeotrope; the condensed overhead splits in a three-phase flash into an organic layer and an aqueous layer, while dry ethanol leaves in the bottoms — the three-phase separation ordinary distillation cannot do.
7 unit ops • NRTL
223 0
View & openDilute acetic acid recovery by extractive distillation
Recovering acetic acid from a dilute aqueous stream (e.g. cellulose acetate or terephthalic acid plant wastewater) using diisobutyl ketone (DIBK) as an extractive entrainer. Because acetic acid and water form no azeotrope but have a relative volatility that flattens toward 1 as the mixture concentrates, straight distillation needs an impractically tall column and heavy reboil duty; the entrainer raises water's relative volatility so the extractive column takes water overhead in far fewer stages, and a second column then strips the entrainer from the acid bottoms for recycle. Modeled with NRTL, and the property method is the whole point here rather than a detail: an entrainer works by changing liquid non-ideality, and a cubic equation of state with van der Waals mixing has no term for it — no binary interaction parameter ships for acetic-acid/water or DIBK/water, so Peng-Robinson runs this flowsheet at kij = 0 and represents none of the effect the column depends on. It does not converge either. NRTL carries the DECHEMA-fitted acetic-acid/water binary and reaches the DIBK pairs through UNIFAC.
7 unit ops • NRTL
226 1
View & openIonic liquid breaks the ethanol-water azeotrope
The ethanol-water azeotrope is a wall: at 89.4 mol% ethanol the vapour and the liquid have the SAME composition, relative volatility is 1, and no number of trays gets you past it. This flowsheet walks through it by adding an involatile ionic liquid, [EMIM][BF₄], which binds water preferentially and pulls the two apart. The numbers are the demonstration. NRTL puts the relative volatility at the azeotrope at 0.996 — that is the wall, computed, not asserted. Add the IL and it climbs to 2.10 at 10 mol%, 2.98 at 20%, and 3.66 at 30%. Flash the IL-laden mixture here and the vapour comes off at an ethanol:water ratio of 22.6 against the azeotrope's 8.43 — decisively across. Run the same feed with no IL and there is nothing to separate: the mixture goes straight from all-liquid to all-vapour with no useful two-phase band, which is precisely what an azeotrope means. Why an IL rather than the usual glycol entrainer (see 'anhydrous-ethanol-extractive-distillation'): an ionic liquid has effectively no vapour pressure, so it never contaminates the distillate and it regenerates by flashing rather than by a second column. Bounded, and this is why the example is a flash and not a column: the IL package models the phase behaviour — which is what decides whether an entrainer works — but omits the IL's own pure-component enthalpy, so a rigorous column energy balance is a follow-up. The separation shown here needs only the phase equilibrium. The IL also carries no molar mass in the databank, so mass-basis readouts show a dash; the mole-basis flash is exact.
6 unit ops • IONIC-LIQUID
93 0
View & open