Ternary Diagrams - University of Utah

Where are we?• In the textbook, this is Section 5 ofChapter 4 • In the notes, this is the set on Single StageEquilibrium • Just finished flash drums

Example Problem• We’ll do an example problem involvingwater, ethylene glycol, and furfural !• Furfural completely dissolves ethyleneglycol, but only partially dissolves waterSolventWe’re using furfural to separateethylene glycol from waterSoluteCarrier

Triangle Diagram: BasicsIf you forget how toread the compositions, use the zero lines0Ternary mixtureBe careful in reading back to the composition!Ethylene GlycolWater01PURE11 PURE PUREBinary mixture withno waterBinary mixture withno furfuralBinary mixture withno ethylene glycolFurfural0

Triangle Diagram:Miscibility Boundary10We need to be in the two-phaseregion (extract & raffinate)SinglePhaseRegionMiscibility BoundaryEthylene GlycolWatermade by adding water toethylene glycol & furfuralmixture until there is cloudiness (2nd phase)Two Phase Region011Furfural0

Triangle Diagram:Tie Lines & Plait PointPlait PointTie lines converge to the Plait Point, where both liquid phases (extract and raffinate) have the same composition10Tie LinesTie lines connect equilibrium points on the miscibility boundaryAt 2-phase equilibrium,these are our extract andraffinate compositions!Ethylene GlycolExtractComposition(Phase 1)Mix(Feed + Solvent)WaterRaffinateComposition(Phase 2)011Furfural0Feed + Solvent --> Mix composition --> Tie Line --> Extract and Raffinate composition at two-phase equilibrium

Triangle Diagram:Getting the Input Point10Points S and F define the linethe mix point M is found with the inverse-lever-arm ruleflow ratesEthylene GlycolFFeedcomp.FS = SMMFMWaterMix0S11Furfural0Solvent composition

Triangle Diagram:Getting the Outflows10Find the tie line that point M lies onExtend to the extract and raffinate compositionsUse the inverse-lever-arm rule again...Ethylene GlycolRunknown flow ratesER = RMEMMMixWaterTotal mass/mole balance to completeE + R = F + S01EFurfural01geometrically:EM + RM = ER