Distillation Physical Properties Calculators

Ok .... heres my collection of Ethanol-Water physical properties, and some of the correlations that I have derived from them. If you can contribute any usefull data, please e-mail me : Tony.Ackland@comalco.riotinto.com.au

Here's what I've got so far ...(with absolutely bloody no guarantees about its accuracy or correctness !!!)

Basic Data for Ethanol-Water Binary Mix



Physical Properties

ValueUnitsEthanol Water Reference
Liquid density g/mL0.789 1.000 Perry 3.2
Vapour density @ 90C g/mL0.0015 0.001 PV=nRT
Molecular weight g/mol46.0634 18.0152 Perry 3.2
Liquid Heat Capacity J/gK2.845 4.184 Perry 3-183
Heat of Vapourisation J/g 855 2260 Perry 3-178
Vapour Pressure @ 90C torr1187 525 Perry 13-4
Liquid Viscosity kg/ms0.00037 0.00032 Perry 3-252
Vapour Viscosity kg/ms108 x 10-7125 x 10-7Perry 3-311
Surface Tension @ 20C mN/m22.39 72.75 Kay & Laby
Vapour Diffusivity ethanol/waterm2/s??
Vapour Diffusivity ethanol/airm2/s102 x 10-7Perry 3-319
Liquid Diffusivity ethanol/waterm2/s128 x 10-11Perry 3-319

Perry = Perry's Chemical Engineers' Handbook, 6th Ed, 1987, Robert H. Perry & Don Green
Kaye & Laby = Tables of Physical & Chemical Constants, Kaye & Laby, 16th Ed, 1995

Vapour Pressure

log (P_sat) = A - B/(T+C) : P_sat [torr], T [C]
torr x 133.22 = Pa

Perry 13-4

SpeciesABC
Ethanol8.11221592.864226.184
Water 8.071311730.63233.426

At C Ethanol : kPa Water : kPa


Heat of Vapourisation

Hv = Ho * ( (1-T/Tc)/(1-To/Tc) ) ^ (A +B(1-T/Tc))

ValueEthanolWater
Ho38743.8440799.86
Tc513.9647.3
A0.320.19
B-0.140.21

At C Ethanol : J/mol Water : J/mol
Ethanol : J/g Water : J/g


Surface Tension

st [mN/m] = 24.05 - 0.0832 x T [oC] in range 10-70 oC


At oC Ethanol surface tension is mN/m


Equilibrium Data

The molar data is from Perry 13-12, I've done the conversions to mass fraction and volume fraction, using the density and molecular weight data above.

Temperature

Mole Fraction

Mass Fraction (g/g)

Volume Fraction (mL/mL)

(C)

Liquid (x)

Vapour (y)

Liquid (x)

Vapour (y)

Liquid (x)

Vapour (y)

95.5

0.019

0.170

0.0472

0.3437

0.0591

0.3990

89

0.072

0.389

0.1657

0.6196

0.2012

0.6736

86.7

0.097

0.438

0.2147

0.6654

0.2573

0.7160

85.3

0.124

0.470

0.2654

0.6943

0.3141

0.7422

84.1

0.166

0.509

0.3374

0.7260

0.3923

0.7705

82.7

0.234

0.545

0.4381

0.7535

0.4971

0.7948

82.3

0.261

0.558

0.4743

0.7635

0.5334

0.8036

81.5

0.327

0.583

0.5544

0.7811

0.6119

0.8189

80.7

0.397

0.612

0.6269

0.8014

0.6804

0.8365

79.8

0.508

0.656

0.7252

0.8301

0.7698

0.8609

79.7

0.520

0.660

0.7346

0.8322

0.7782

0.8628

79.3

0.573

0.684

0.7745

0.8470

0.8132

0.8753

78.74

0.676

0.739

0.8423

0.8784

0.8713

0.9015

78.24

0.747

0.782

0.8831

0.9014

0.9055

0.9206

78.15

0.894

0.894

0.9558

0.9558

0.9648

0.9648



Correlations


Converting these to something useful...


Vapour-Liquid Equilibrium


%vap = -94.7613*x ^ 8 + 450.932 * x ^ 7 - 901.175 * x ^ 6 + 985.803 * x ^ 5 - 644.997 * x ^ 4 + 259.985 * x ^ 3 - 64.5050 * x ^ 2 + 9.71706 * x

where %vap = % of ethanol in vapour if condensed (mL per mL), and x = % of ethanol in liquid (mL per mL).
If the wash is % alcohol (liquid), the vapour will be % alcohol



Temperature


T (in C) = 60.526 * %liq ^ 4 - 163.16 * %liq ^ 3 + 163.96 * %liq ^ 2 - 83.438 * %liq + 100
At % alcohol (liquid) the wash will boil at oC





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