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The Properties Specifications Global sheet is used to enter the
thermodynamic methods used to calculate the properties used in
the simulation.
1 From the Data Browser, open the Properties folder and select
Specifications.
The Properties | Specifications | Global sheet appears. The
Electrolyte Wizard has already completed this sheet:
The Electrolyte-NRTL activity coefficient model, ELECNRTL,
is the recommended option set for simulations with
electrolytes. ELECNRTL calculates liquid phase properties
from the Electrolyte-NRTL activity coefficient model. Vapor
phase properties are calculated from the Redlich-Kwong
equation of state.
ELECNRTL can represent aqueous and aqueous/organic
electrolyte systems over the entire range of electrolyte
concentrations with a single set of binary interaction
parameters. In the absence of electrolytes, the model reduces to
the standard NRTL model.
Aspen Plus contains a databank of binary interaction
parameters between water and over 600 electrolyte ion pairs. If
the binary interaction parameters between any solvent and an
electrolyte ion pair are missing from the databank, and you do
not provide values, Aspen Plus provides reasonable default
values.
2 Click to continue.
Getting Started - Electrolytes Modeling Electrolyte Chemistry • 2-15
The Binary Interaction | HENRY-1| Input sheet appears.
Use this sheet to view the Henry's Law parameters retrieved by
the electrolytes expert system. If you had your own Henry's
Law parameters, you would enter them on this sheet.
3 Click to continue.
The Binary Interaction | VLCLK-1 | Input sheet appears.
Use this sheet to view the Clarke density parameters retrieved
by the electrolytes expert system. If you had your own Clarke
density parameters, you would enter them on this sheet.
4 From the Data Browser, select the Properties | Parameters |
Electrolyte Pair folder.
The Electrolyte Pair sheets define the electrolyte pair
parameters: GMELCC, GMELCD, GMELCE, and GMELCN.
If you had your own pair parameters, you would enter them on
these sheets.
5 Click to continue.
The Electrolyte Pair | GMELCC-1 | Input sheet appears.
6 Click to continue.
The Electrolyte Pair | GMELCD-1 | Input sheet appears.
7 Click to continue.
The Electrolyte Pair | GMELCE-1 | Input sheet appears.
8 Click to continue.
The Electrolyte Pair | GMELCN-1 | Input sheet appears.
9 Click to continue.
The Required Properties Input Complete dialog box appears:
2-16 • Modeling Electrolyte Chemistry Getting Started - Electrolytes
Correct representation of physical properties is essential to
process modeling. For many simulations, the only physical
property specification that you must provide is the selection of
a property method. This dialog box shows that the Aspen Plus
physical property system has many optional capabilities to
increase the accuracy of the physical property calculations.
Because the Aspen Plus electrolytes database has data for all
components and pairs in this simulation, you don't need to
provide any optional specifications or data.
Now that the Components and Properties specifications are
complete, complete the rest of the flowsheet specifications in
the same way as for nonelectrolytes. There are no stream or
block restrictions in using Aspen Plus electrolytes. You can use
all Aspen Plus unit operation models in an electrolytes
simulation.
10 Click OK to move to the next required input.
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