A short Primer for Using Aspen Plus® process
simulation software
There are many subprograms within the Aspen Tech family of software tools. This short
primer focuses on Aspen Plus®, a process simulation tool. Many of the other tools
integrate into Aspen Plus® while others are stand-alone systems. This first primer outlines
a simple flowsheet involving a distillation column. Hopefully it provides some useful
introduction to Aspen without involving unessential details.
I provide considerable editorial information in this primer that I hope is useful but that
makes it longer than necessary. The essential steps to completing this problem can be
executed by focusing on the numbered items only and ignoring the introductory
explanations and figures in each section. The entire process should take less than 15
minutes in this mode.
Getting Started
1. Navigate to the Aspen Plus User Interface program which will generally be found
under the following sequence of program menus Aspen Tech -> Aspen
Engineering Suite -> Aspen Plus 2004.1 -> Aspen Plus User Interface.
2. The first dialog box you encounter asks you to select either a new simulation or
choose among existing simulations saved to a disk, the latter choice including a
listbox of past simulations. Here we assume you are starting a new simulation.
You may choose either a blank simulation or a template. Here we assume you
want to choose a template. Select Template and OK. Figure 1 illustrates this
dialog box with some of the important selections discussed above highlighted
with red ovals.
Figure 1Opening dialog box in Aspen Plus®
3. The next dialog box has two tabs – one for simulations and one for refineries.
Choose the simulation tab for this primer. Also, the lower right corner has a dropdown list box labeled Run Type. Choose Flowsheet for this primer (see Appendix
for other options). Finally, choose a process type and units in which you want to
work from the list of options in dialog box. Here we suggest a Generic Simulation
with English Units. All of these choices can be modified later in the program if
desired. The essential difference among the process types is that Aspen preselects
the thermodynamic models most appropriate for the given process. However, you
are able to override these pre-selected choices if you choose to do so. Figure 2
illustrates this dialog box with some of the important selections discussed above
highlighted with red ovals.
Figure 2Second dialog box in Aspen Plus with selection of process type and run type.
4. You should now have a blank process simulation window open. Also, there
should be series of unit operations choices called the Model Library along the
bottom of the dialog box. If the Model Library does not appear, select Model
Library under the View menu at the top of the page. This page is illustrated in
Figure 3.
5. You are now ready to construct a simulation.
6. From this point on, you can step through the minimally required input fields by
selecting the Next button at the top of the page (an uppercase, blue N with a rightpointing arrow – highlighted with a red oval near the top of Figure 3). The Next
function can alternatively be accessed by pressing F4 or by selecting it from the
Tools menu. This will lead you through the various stages of setting up a
simulation.
7. Help files are available at any point from the help menu or, for context-sensitive
help, by pointing at the item with which you want help and pressing F1. However,
Aspen includes several separate help files. They are each accessible from the
same menu, but searches and lists of help topics in the help interface are limited to
the help file that is open. For example, the default help file for the flowsheet is the
Aspen Plus Help file. It contains few details beyond the name and typical
application for the thermodynamic models used within Aspen. For detailed
thermodynamic information (form of equations, temperature and pressure
dependence, etc.), you must select the Aspen Physical Property System Help file.
This (or any of several other help files) can be found by navigating to the Topics
tab in any help file and selecting the topmost choice (a document, not a folder)
labeled Accessing Other Help in the tree-structured illustration of the help file
found in the left panel. The right panel will then include links to all help files
loaded in your software.
Figure 3An example of a blank flowsheet, the starting point for process simulation, with several of
the items discussed above highlighted with red ovals.
Building the Flowsheet
The flowsheet is a graphical representation of your process. Aspen works somewhat more
elegantly if you first place equipment from the Model Library on the flow sheet and then
connect these major components with streams rather than, for example, placing feed
streams on the flowsheet and connecting streams and equipment in the order they are
encountered in the process. However, either approach as well as many other approaches
will eventually work. Note that Aspen seems generally unaware of gravity (an important
consideration in liquid-liquid extraction processes) and of flow direction, but my
preference is to represent flow from left to right where possible (recycle streams being an
exception) and to try to place all initial (feed) and terminal (product) flow stream points
such that they do not need to cross other flow lines to reach the flowsheet border – that is,
to not leave them embedded in the diagram surrounded by flowlines and equipment.
Note that the tabbed titles of the unit operations in the Model Library can be slightly
misleading. For example, the tab Separators includes only simple separators such as flash
drums or columns with specified output concentrations but not with model capabilities to
predict such concentrations. Distillation columns and liquid-liquid separators are included
in the Columns tab. Also pumps, compressors, turbines, etc. are under the tab Pressure
Changers. If your pointer hovers over any portion of the model library (or another hotspot
in the open window), the status bar (bottom-most portion of the window) displays a short
description of the unit operation that is quite useful in making selections.
Depressurization equipment such as turbines are modeled with the same tools as
compressors and pumps although the labels do not make this obvious but the status bar
description does. Also note that alternative icons for many of the unit operations are
available by clicking on the down arrow to the right of each existing icon. So far as I
know, these are cosmetic only. They do not change functionality, although they
sometimes appear to do so (distillation column with or without condenser specifically
drawn still has the some choices for inlet and outlet streams, for example).
1. Choose equipment from the Model Library and place it on the flowsheet by
dragging it to the blank (white) area of the screen. Here we choose RadFrac from
the columns tab, which is a rigorous, multicomponent, multiphase distillation
column model. Note that nearly all equipment (indeed all equipment so far as I
know) receives a default label of B*, consistent with flowsheet labeling practices
generally not too informative. These labels can be changed by selecting (single
clicking) the equipment and choosing cntrl-M or by right-clicking on it and
choosing Rename Block.
2. Connect feed, intermediate, and product lines to the equipment. This is done by
selecting the left-most icon from the Model Library which is labeled Material
Streams. Doing so causes each piece of equipment on the flowsheet to indicate
with red arrows the required inlet/outlet streams and to indicate with blue arrows
optional inlet and outlet streams. Connect the equipment by clicking on a red or
blue arrow and moving the pointer to either another arrow on another piece of
equipment (in the case of intermediate streams) or to a convenient and
aesthetically acceptable location on the flowsheet (in the case of feed and product
streams). Note that specifying a stream sometimes changes the status of remaining
streams for a piece of equipment. In this example, specifying a condenser liquid
stream changes the condenser vapor stream from red (required) to blue (optional)
since at least one liquid or vapor stream is required, but not necessarily both.
Stream labels default to numerically increasing numbers in the order in which you
place them on the sheet. These can be changed, as with equipment, by selecting
(single clicking) the equipment and choosing cntrl-M or by right-clicking on it
and choosing Rename Stream. The flowsheet should now look like Figure 4,
except possibly with more meaningful labels for the equipment and streams if you
choose to rename them.
B2
2
1
3
Figure 4Flowsheet illustration for a simple distillation column process.
3. After connecting all streams select the Next button near the top of the screen (or
choose it by pressing F4 or by selecting it from the Tools menu). If all streams are
properly connected, a dialog box for the project title and default specifications
will open. Otherwise, an indication of a problem will appear.
Overall Specifications
At this point you should be in the Data Browser. This is probably the first time you have
encountered it, but it is central to the program. The insert prompt should be located in a
text box labeled Title and is asking for you to enter a name for the process you are
simulating. Any title (or no title) is fine here. This is possibly the only non-essential
portion of the series of entries the program will ask you to make using the Next button.
However, take a moment to get a feel for the Data Browser as it will be a major interface
to everything else that happens.
Along the left side of the Data Browser dialog box is a tree structure that organizes the
input and output data. The portions that have blue check boxes have all the information
they need but those with red half-full signs require additional input. The Next button will
step through these in a logical sequence, or you can go directly to them using the tree
view. The logical sequence is essentially the same as the order in which red (incomplete)
items appear in this tree view. That is, next you will be asked to specify the components
in the system, then the thermodynamic models you want to use, then the components in
individual streams, then you will skip the defaults for the flowsheet itself as these should
already be specified, then you will specify the concentration and condition (pressure,
temperature, phase, etc.) of components in feed streams, and the final required input will
be specifications for the equipment (blocks) in the process – in this case a single
distillation column.
There are a great number of additional options that involve optimization, design, costs,
convergence, etc., but these are not discussed here. For now, the task at this stage is
simple
1. Enter a suitable name for this process
2. Press the Next button
Component Specification
You should now be in the Components Specification section of the Data Browser. In the
tree diagram at the left you can tell where you are by locating the highlighted portion of
the tree. Also, the title of the dialog box should indicate similar information.
There are four specifications for each component (chemical species) that you wish to use
in the calculation. The first is the ID, which is an arbitrary label of up to eight characters
and numbers. An ID that closely resembles the species name is highly preferred as this ID
is used in the output to indicate concentrations, etc. The type will, for now, always be
conventional (other types allow for solids, pseudo species, etc., but conventional is
suitable for any fluid – liquid or gas – material that is an actual chemical species likely to
be available in the extensive Aspen database). The component name is the name Aspen
databases use for this component. If the ID is the name, such as ACETONE or
ETHANOL, Aspen automatically fills in all remaining boxes for each component. If the
eight-character limit of the ID is too short for the actual name or if there are several
common names for the component, such as BUTANOL, you must help Aspen identify
what you mean. This can be done by typing in as much of the name as will fit in the ID
and choosing the correct species from the list Aspen automatically presents or by using
the Find button at the bottom of this dialog box, in which case Aspen offers several
suggestions based on what you enter and you are to select one. Note that only the species
entered in this dialog box are considered in any calculations – specifically processes that
involve chemical reactions or equilibrium reactions only select from the choices entered
here.
In this case, we specify acetone, ethanol, n-butanol, and phenol as the components.
1. Enter IDs in the ID column
2. Complete specifications for any species Aspen does not recognize according to
instructions above.
3. Click the Next button
(Thermodynamic) Properties Specifications
You should now have the dialog box used to specify thermodynamic models open. This
dialog box is where most of the art of thermodynamics lies. The first box asks for the
type of process. The function of this box is to select the most appropriate subset of
possible thermodynamics models for selection in subsequent boxes. You can select from
the dropdown box by clicking on the arrow. As your curser passes entries, a few words of
explanation appear in the bottom box. You may note that the prompts in the bottom panel
of this box generally suggest you use the Property Method Selection Assistant. This is
found on the tools menu. In this case, we will leave the process as ALL, indicating all
thermodynamic options will be available to us.
The next dropdown box requests the default thermodynamic model for the process.
Different models can be used within individual blocks of the process, but the base model
is specified here. Again, the Property Method Selection Assistant is useful in making
these selections. For our simple system, there are many appropriate choices. We will try
UNIQUAC with ideal gas and Henry’s law for non-condensable components, which is
specified as UNIQUAC.
The remainder of the dialog box allows non-condensable gas components to be specified
and a variety of specialty modifications to be made for electrolytes, changes in binary
interaction parameters, etc., but none of these is essential for our problem.
Clicking Next will bring you to the parameters dialog box. Generally, nothing needs to be
specified here. It simply reviews the parameters, mostly the binary interaction
parameters, available for the components in this system. These are pre-selected by Aspen
for your problem but can be changed to better suit your purposes. This dialog box may
represent the single greatest distinguishing characteristic of Aspen. It appears to have
more sophisticated equilibrium models and much more extensive databases of interaction
parameters than many of its competitors. Within the information it presents, some of the
important information includes the temperature range over which the BIPs are valid
(appears near the bottom of the table for each pair) and the values of the BIPs (all zeros
indicate no information available but nearly all zeros is not an indication of bad
information – the various parameters are often for temperature dependencies, etc. and not
all of them would be expected to be non-zero in general). The final important
consideration is the database from which the data come. There are many databases within
Aspen and while it tries to select the most appropriate for your problem, you may find a
more suitable one within the choices. For example, butanol and acetone form immiscible
liquid solutions under some conditions and, if these are important to the process, the
liquid-liquid equilibrium (LLE) database which is presumably optimized to predict phase
immiscibilities rather than the vapor-liquid equilibrium (VLE) database may be more
suited for the simulation. Both can potentially predict two phases, but the former would
presumably be more accurate. The database-provided entries appear in grayed-out text.
Highlighting any one of these parameters and selecting help (F1) pops up an information
box that summarizes the temperature, pressure, and composition range on which the data
are based, the number of data points, and the goodness of fit measured several ways. If
you change a parameter, it becomes black rather than gray and Aspen assumes it is your
information, in which case this database information is not available from Help.
For this case, the entries are relatively simple
1. Specify ALL for the Process Type
2. Specify UNIQUAC for the Base Method
3. Press Next
4. Review the temperature-dependent interaction parameter data but don’t change
anything
5. Press Next
This should bring you to the stream specification section.
I provide a short list of the thermodynamic models and a logic diagram I tried to develop
but with which I am not satisfied in the Appendix.
Streams
This section allows you to specify stream conditions (composition, temperature, pressure,
etc.). The stream for which data are being entered appears in the title of the dialog box
which, although prominent, is easily overlooked. It will have the same ID as it has on the
flowsheet. Generally, at least two of temperature, pressure, or fraction of vapor must be
specified, with the remaining parameter calculated from thermodynamics. The units for
the specifications are based on the default units selected at the beginning of the run but
can be changed locally if desired. The composition of the stream can be specified in a
variety of ways (mole fraction, mass fraction, flow rates, etc.). If you select an intensive
specification, then the total flow must also be specified.
In this case
1. Specify a saturated liquid (0 vapor fraction)
2. Specify14.7 psi
3. Specify an equimolar composition of 25 lb mols/hr flow rate for each of the four
components.
4. Press Next
Since the remaining streams in this simple simulation are all products, there are no more
specifications in the stream section and you should now be at the Block Setup dialog box.
Block Setup
Every type of unit operation has different specifiable parameters. In this case, we have a
distillation column. In this dialog box we indicate whether we want to use an
equilibrium-based model (by far the most common) or a rate-based model (in some
circles more respected and an increasingly important approach). We will use the
equilibrium approach here.
Next we specify the total number of stages. This should be distinguished from the
number of trays as the number of stages potentially includes the condenser (rarely – only
if it is a partial condenser) and the reboiler (generally – unless it is a total reboiler). We
specify 9 in this case. The type of condenser is specified from among the several choices.
We choose a simple total condenser. We accept the defaults for everything else in the
setup.
We next specify the operation. Generally two of the many potential specifications are
required. We choose a total distillate rate of 50 lb mols/hr and a reflux ratio of 5.
Pressing next takes us to the next tab in this specification where we indicate the feed
stage location, which we take as above the 5th stage.
Pressing next again takes us to the pressure specification where we specify the pressure at
the condenser. If no other pressure or pressure drop is specified, the entire column is
assumed to operate at this pressure.
Aspen can be used for design (calculating, for example, the reflux ratio needed to achieve
a target separation), optimization, cost accounting, etc. but its default use is as a simulator
and that is what is illustrated here. I will try to write another primer for design, etc. uses.
In this case
1. Accept the default equilibrium specification for the column
2. Specify 9 total stages in the column
3. Accept the defaults for the remaining flows setup parameters.
4. Specify a total distillate flow of ½ of the inlet flow (50 lb mols/hr) and a reflux
ratio of 5.
5. Press Next
6. Specify that the feed is located above the 5th stage.
7. Press Next
8. Specify the column pressure is 1 atm (14.7 psi) at the condenser and no changes
across the stages (no entries in remaining boxes).
9. Press Next
This completes all of the specifications. Pressing next should pop up a dialog box that
tells you that Aspen knows enough to complete the simulation and ask you if you want to
further specify anything. If you select Run, Aspen predicts the resulting compositions,
temperatures, and pressures of the product streams, the stage-by-stage compositions of
vapor and liquid in the column, and all other details of the process.
Reviewing the Results
During the simulation, Aspen displays convergence and other data in a new dialog box
called the Control Panel (perhaps a misnomer as there is essentially nothing that can be
controlled from this dialog box – it is mainly informational). If the simulation converges,
it will complete with a statement  Simulation calculations completed. For this simple
problem, this should not take long although it does take some time for the computation to
set itself up.
To view the results, close the Control Panel, in which case the Data Browser should be
displayed. At the bottom of the tree structure on the left of the Data browser is the Results
Summary section. Open this section of the structure and choose streams to obtain a
summary of the stream compositions, flows, temperatures, and pressures. This should
display a table of stream properties. In this case, the column performs a sharp separation
of the two light components (acetone and ethanol) from the two heavy components
(butanol and phenol) at temperatures near those of steam and hot water, as might be
expected. A copy of this summary information can be included on the flowsheet by
pressing the Stream Table button. In my case, the results look like Figure 5.
B2
2
1
3
Simple Dist illat ion Colum n
Stream ID
1
2
3
T emperat ure
F
188.2
143.8
272.3
P ressure
psi
14.70
14.70
14.70
Vapor Frac
0.000
0.000
0.000
100.000
50.000
50.000
6809.623
2608.586
4201.037
132.753
55.931
80.871
-10.335
-5.508
-4.678
ACET ONE
25.000
24.956
0.044
ET HANOL
25.000
24.852
0.148
BUT ANOL
25.000
0.192
24.808
P HENOL
25.000
trace
25.000
Mole Flow
lbmol/hr
Mass Flow
lb/hr
Volume Flow
cuft/hr
Enthalpy
MMBt u/hr
Mole Flow
lbmol/hr
Figure 5Summary of stream conditions and flow diagram for this simple Primer.
To examine more details of column performance, return to the block specifications and
click on the profiles button. Here the stage-by-stage compositions, temperatures, kvalues, etc. are displayed. As indicated, there are significant compositional changes
between every stage. These can be conveniently plotted within Aspen by running the Plot
Wizard found under the Plot menu in the Data Browser. For example, the gas and liquid
phase composition for the problem appear in Figure 6.
1
Block B2: Vapor Composition Prof iles
0.9
ACETONE
ETHANOL
0.8
BUTANOL
0.1
0.2
0.3
Y (mole frac)
0.4 0.5 0.6
0.7
PHENOL
2
3
4
5
Stage
6
7
8
9
7
8
9
Block B2: Liquid Composition Profiles
1
1
ACETONE
ETHANOL
0.8
BUTANOL
0.2
X (mole frac)
0.4
0.6
PHENOL
1
2
3
4
5
Stage
6
Figure 6Vapor (top) and liquid compositions on a stage-by-stage basis in the simple column used in
this primer. Stage 1 is at the top of the column and Stage 9 is the reboiler.
Appendix
Run Types
The following descriptions of alternative run types indicate the range of choices within
Aspen, including the Flowsheet (process simulator) choice.
Run Type
Assay Data Analysis
Data Regression
Description
A standalone assay data
analysis/pseudocomponents
generation run
A
standalone
data
regression run. Can contain
property constant estimation
and
property
analysis
calculations.
Flowsheet
A
process
simulation
option, including sensitivity
studies and optimization.
Properties Plus
A Properties Plus setup run
Property Analysis
A
standalone
property
analysis run. Can contain
property constant estimation
and assay data analysis
calculations.
A
standalone
property
constant estimation run
Property Estimation
Use to
Analyze assay data when you do
not want to perform a flowsheet
simulation in the same run.
Fit physical property model
parameters
required
by
Aspen Plus to measured pure
component, VLE, LLE and other
mixture data. Aspen Plus cannot
perform data regression in a
Flowsheet run.
Simulate complete processes.
Flowsheet simulations include
Property Estimation, Assay Data
Analysis, and Property Analysis
capabilities but Data Regression
cannot be done within the
Flowsheet option.
Prepare a property package for
use with Aspen Custom Modeler
or Aspen Pinch, with third-party
commercial
engineering
programs, or with your company's
in-house programs. You must be
licensed to use Properties Plus.
Perform property analysis by
generating tables of physical
property values when you do not
want to perform a flowsheet
simulation in the same run
Estimate property parameters
when you do not want to perform
a flowsheet simulation in the
same run.
Summary of Aspen Property Methods
Ideal Property Methods
Ideal Property Method
IDEAL
SYSOP0
K-Value Method
Ideal Gas/Raoult's law/Henry's law
Release 8 version of Ideal Gas/Raoult's law
Equations of State
Abbreviation
BWR-LS
LK-PLOCK
PENG-ROB
PR-BM
PRWS
PRMHV2
PSRK
RKSWS
RKSMHV2
RK-ASPEN
RK-SOAVE
RKS-BM
SR-POLAR
Equation of State
Lee-based Methods
BWR Lee-Starling
Lee-Kesler-Plöcker
Peng-Robinson-based Methods
Peng-Robinson
Peng-Robinson with Boston-Mathias alpha function
Peng-Robinson with Wong-Sandler mixing rules
Peng-Robinson with modified Huron-Vidal mixing rules
Redlich-Kwong-based Methods
Predictive Redlich-Kwong-Soave
Redlich-Kwong-Soave with Wong-Sandler mixing rules
Redlich-Kwong-Soave with modified Huron-Vidal mixing rules
Redlich-Kwong-ASPEN
Redlich-Kwong-Soave
Redlich-Kwong-Soave with Boston-Mathias alpha function
Other Methods
Schwartzentruber-Renon
Activity Coefficient Methods
Abbreviation
PITZER
PITZ-HG
B-PITZER
ELECNRTL
ENRTL-HF
ENRTL-HG
NRTL
NRTL-HOC
NRTL-NTH
NRTL-RK
NRTL-2
UNIFAC
UNIF-DMD
UNIF-HOC
UNIF-LBY
UNIF-LL
UNIQUAC
UNIQ-HOC
UNIQ-NTH
UNIQ-RK
UNIQ-2
VANLAAR
VANL-HOC
VANL-NTH
VANL-RK
VANL-2
WILSON
WILS-HOC
WILS-NTH
WILS-RK
WILS-2
WILS-HF
WILS-GLR
WILS-LR
WILS-VOL
Liquid Activity Coefficient
Vapor Fugacity Coefficient
Pitzer-based Methods
Pitzer
Redlich-Kwong-Soave
Pitzer
Redlich-Kwong-Soave
Bromley-Pitzer
Redlich-Kwong-Soave
NRTL-based Methods
Electrolyte NRTL
Redlich-Kwong
Electrolyte NRTL
HF Hexamerization model
Electrolyte NRTL
Redlich-Kwong
NRTL
Ideal gas
NRTL
Hayden-O'Connell
NRTL
Nothnagel
NRTL
Redlich-Kwong
NRTL (using dataset 2)
Ideal gas
UNIFAC-based Methods
UNIFAC
Redlich-Kwong
Dortmund-modified UNIFAC
Redlich-Kwong-Soave
UNIFAC
Hayden-O'Connell
Lyngby-modified UNIFAC
Ideal gas
UNIFAC for liquid-liquid systems
Redlich-Kwong
UNIQUAC-based Methods
UNIQUAC
Ideal gas
UNIQUAC
Hayden-O'Connell
UNIQUAC
Nothnagel
UNIQUAC
Redlich-Kwong
UNIQUAC (using dataset 2)
Ideal gas
VANLAAR-based Methods
Van Laar
Ideal gas
Van Laar
Hayden-O'Connell
Van Laar
Nothnagel
Van Laar
Redlich-Kwong
Van Laar (using dataset 2)
Ideal gas
WILSON-based Methods
Wilson
Ideal gas
Wilson
Hayden-O'Connell
Wilson
Nothnagel
Wilson
Redlich-Kwong
Wilson (using dataset 2)
Ideal gas
Wilson
HF Hexamerization model
Wilson (ideal gas and liquid enthalpy Ideal gas
reference state)
Wilson (liquid enthalpy reference Ideal gas
state)
Wilson with volume term
Redlich-Kwong
Specialty Methods
Abbreviation
AMINES
K-value Method
Kent-Eisenberg amines model
Application
H2S, CO2, in MEA,
DEA, DIPA, DGA
solution
API sour water model
Sour water with NH3,
H2S, CO2
Braun K-10
Petroleum
Ideal Gas/Raoult's law/Henry's law/solid activity Pyrometallurgical
coefficients
Chao-Seader corresponding states model
Petroleum
Grayson-Streed corresponding states model
Petroleum
ASME steam table correlations
Water/steam
NBS/NRC steam table equation of state
Water/steam
APISOUR
BK-10
SOLIDS
CHAO-SEA
GRAYSON
STEAM-TA
STEAMNBS
Property Methods Decision Diagram
Yes
Yes
A
WILSON
NRTL
UNIQAC
etc.
A
UNIF-LL
A
UNIFAC
UNIF-LBY
UNIF-DMD
A
Liq-Liq
ELECNRTL
No
Yes
Yes
Yes
NRTL
UNIQAC
etc.
Interaction
Parameters
Available?
Liq-Liq
No
Pr < 0.1 &
T < Tci
No
No
Yes
Electrolyte
Yes
Interaction
Parameters
Available?
No
Property Method
Choice
SR-POLAR
PRWS
RKSWS
PRMHV2
RKSMHV2
Polar or
T < Tci
Yes
No
PENG-ROB
PR-BM
LK-PLOCK
RK-SOAVE
RKS-BM
No
WILS-NTH, WILS-HOC,
NRTL-NTH, NRTL-HOC,
UNIQ-NTJ, UNIQ-HOC,
Dimers
UNIF-HOC
PSRK
RKSMHV2
Degree of
Polymerization
No Pseudo
Components
Yes
CHAO-SEA
GRAYSON
BK10
Yes
Hexamers
No
High Pressure?
No
A
WILS-HF
Vapor-phase
Association?
BK10
IDEAL
No
WILSON, WILS-RK, WILS-LR, WILSGLR, NRTL, NRTL-RK, NRTL-2,
UNIQUAC, UNIQ-RK, UNIQ-2, UNIFAC,
UNIF-LL, UNIF-LBY, UNIF-DMB