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Aspen Physical Property System - Physical Property Models

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References<br />

A. L. Horvath, Handbook of Aqueous Electrolyte Solutions, (Chichester: Ellis<br />

Horwood, Ltd, 1985).<br />

Wilke-Chang (Binary)<br />

The Wilke-Chang model calculates the liquid diffusion coefficient of<br />

component i in a mixture at finite concentrations:<br />

Dij l = Dji l<br />

The equation for the Wilke-Chang model at infinite dilution is:<br />

Where i is the diffusing solute and j the solvent, and:<br />

�j = Association factor of solvent. 2.26 for water, 1.90<br />

for methanol, 1.50 for ethanol, 1.20 for propyl<br />

alchohols and n-butanol, and 1.00 for all other<br />

solvents.<br />

Vbi = Liquid molar volume at Tb of solvent i<br />

�j l = Liquid viscosity of the solvent. This can be obtained<br />

from the General Pure Component Liquid Viscosity<br />

model. You must provide parameters for one of<br />

these models.<br />

� l = Liquid viscosity of the complete mixture of n<br />

components<br />

xi, xj = Apparent binary mole fractions. If the actual mole<br />

Parameter<br />

Name/Element<br />

fractions are then<br />

286 3 Transport <strong>Property</strong> <strong>Models</strong><br />

Symbol Default Lower<br />

Limit<br />

Upper<br />

Limit<br />

MW M j — 1.0 5000.0 —<br />

VB V bi *,l<br />

Units<br />

— 0.001 3.5 MOLE-VOLUME

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