Transcript Introductory chapter ip21 foundation

Introduction to Flowsheet Simulation
Objective:
Introduce general flowsheet simulation concepts
and Aspen Plus features
©2000 AspenTech. All Rights Reserved.
Flowsheet Simulation
• What is flowsheet simulation?
Use of a computer program to quantitatively model the
characteristic equations of a chemical process
• Uses underlying physical relationships
– Mass and energy balance
– Equilibrium relationships
– Rate correlations (reaction and mass/heat transfer)
• Predicts
– Stream flowrates, compositions, and properties
– Operating conditions
– Equipment sizes
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Advantages of Simulation
• Reduces plant design time
– Allows designer to quickly test various plant configurations
• Helps improve current process
– Answers “what if” questions
– Determines optimal process conditions within given constraints
– Assists in locating the constraining parts of a process
(debottlenecking)
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General Simulation Problem
• What is the composition of stream PRODUCT?
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
• To solve this problem, we need:
COOL-OUT
SEP
PRODUCT
– Material balances
– Energy balances
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Introduction to Aspen Plus
Approaches to Flowsheet Simulation
• Sequential Modular
– Aspen Plus is a sequential modular simulation program.
– Each unit operation block is solved in a certain sequence.
• Equation Oriented
– Aspen Custom Modeler (formerly SPEEDUP) is an equation oriented
simulation program.
– All equations are solved simultaneously.
• Combination
– Aspen Dynamics (formerly DynaPLUS) uses the Aspen Plus
sequential modular approach to initialize the steady state simulation
and the Aspen Custom Modeler (formerly SPEEDUP) equation
oriented approach to solve the dynamic simulation.
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Introduction to Aspen Plus
Good Flowsheeting Practice
• Build large flowsheets a few blocks at a time.
– This facilitates troubleshooting if errors occur.
• Ensure flowsheet inputs are reasonable.
• Check that results are consistent and realistic.
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Introduction to Aspen Plus
Important Features of Aspen Plus
• Rigorous Electrolyte Simulation
• Solids Handling
• Petroleum Handling
• Data Regression
• Data Fit
• Optimization
• User Routines
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
The User Interface
Objective:
Become comfortable and familiar with the Aspen
Plus graphical user interface
Aspen Plus References:
User Guide, Chapter 1, The User Interface
User Guide, Chapter 2, Creating a Simulation Model
User Guide, Chapter 4, Defining the Flowsheet
©2000 AspenTech. All Rights Reserved.
The User Interface
Run ID
Title Bar
Menu Bar
Next Button
Tool Bar
Select Mode
button
Model
Library
Model Menu
Tabs
Status Area
Process
Flowsheet
Window
Reference: Aspen Plus User Guide, Chapter 1, The User Interface
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Introduction to Aspen Plus
Cumene Flowsheet Definition
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
RStoic
Model
COOL-OUT
Heater
Model
SEP
Flash2
Model
PRODUCT
Filename: CUMENE.BKP
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Introduction to Aspen Plus
Using the Mouse
• Left button click
-
Select object/field
• Right button click
-
Bring up menu for selected
object/field, or inlet/outlet
-
Cancel placement of streams or
blocks on the flowsheet
-
Open Data Browser object sheet
• Double left click
Reference: Aspen Plus User Guide, Chapter 1, The User Interface
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Graphic Flowsheet Operations
• To place a block on the flowsheet:
1. Click on a model category tab in the Model Library.
2. Select a unit operation model. Click the drop-down arrow to
select an icon for the model.
3. Click on the model and then click on the flowsheet to place
the block. You can also click on the model icon and drag it
onto the flowsheet.
4. Click the right mouse button to stop placing blocks.
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Graphic Flowsheet Operations (Continued)
• To place a stream on the flowsheet:
1. Click on the STREAMS icon in the Model Library.
2. If you want to select a different stream type (Material, Heat or
Work), click the down arrow next to the icon and choose a
different type.
3. Click a highlighted port to make the connection.
4. Repeat step 3 to connect the other end of the stream.
5. To place one end of the stream as either a process flowsheet
feed or product, click a blank part of the Process Flowsheet
window.
6. Click the right mouse button to stop creating streams.
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Graphic Flowsheet Operations (Continued)
• To display an Input form for a Block or a Stream in the
Data Browser:
1.
Double click the left mouse button on the object of interest.
• To Rename, Delete, Change the icon, provide input or
view results for a block or stream:
1.
2.
3.
Select object (Block or Stream) by clicking on it with the left
mouse button.
Click the right mouse button while the pointer is over the
selected object icon to bring up the menu for that object.
Choose appropriate menu item.
Reference: Aspen Plus User Guide, Chapter 4, Defining the Flowsheet
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Introduction to Aspen Plus
Automatic Naming of Streams and Blocks
• Stream and block names can be automatically assigned
by Aspen Plus or entered by the user when the object is
created.
• Stream and block names can be displayed or hidden.
• To modify the naming options:
– Select Options from the Tools menu.
– Click the Flowsheet tab.
– Check or uncheck the naming options desired.
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Introduction to Aspen Plus
Benzene Flowsheet Definition Workshop
• Objective - Create a graphical flowsheet
– Start with the General with English Units Template.
– Choose the appropriate icons for the blocks.
– Rename the blocks and streams.
VAP1
COOL
VAP2
FL1
FEED
COOL
Flash2
Model
Heater
Model
FL2
LIQ1
Flash2
Model
When finished, save in backup
format (Run-ID.BKP).
filename: BENZENE.BKP
LIQ2
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Introduction to Aspen Plus
Basic Input
Objective:
Introduce the basic input required to run an Aspen
Plus simulation
Aspen Plus References:
User Guide, Chapter 3, Using Aspen Plus Help
User Guide, Chapter 5, Global Information for Calculations
User Guide, Chapter 6, Specifying Components
User Guide, Chapter 7, Physical Property Methods
User Guide, Chapter 9, Specifying Streams
User Guide, Chapter 10, Unit Operation Models
User Guide, Chapter 11, Running Your Simulation
©2000 AspenTech. All Rights Reserved.
The User Interface
• Menus
– Used to specify program options and commands
• Toolbar
– Allows direct access to certain popular functions
– Can be moved
– Can be hidden or revealed using the Toolbars dialog box from
the View menu
• Data Browser
– Can be moved, resized, minimized, maximized or closed
– Used to navigate the folders, forms, and sheets
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The User Interface (Continued)
• Folders
– Refers to the root items in the Data Browser
– Contain forms
• Forms
– Used to enter data and view results for the simulation
– Can be comprised of a number of sheets
– Are located in folders
• Sheets
– Make up forms
– Are selected using tabs at the top of each sheet
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Introduction to Aspen Plus
The User Interface (Continued)
• Object Manager
– Allows manipulation of discrete objects of information
– Can be created, edited, renamed, deleted, hidden, and
revealed
• Next Button
– Checks if the current form is complete and skips to the next
form which requires input
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Introduction to Aspen Plus
The Data Browser
Go back
Go forward
Next sheet
Comments
Parent button
Units
Previous sheet
Status
Next
Menu tree
Status area
Description area
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Introduction to Aspen Plus
Help
• Help Topics
– Contents - Used to browse through the documentation. The
User Guides and Reference Manuals are all included in the
help.
•
All of the information in the User Guides is found under the “Using
Aspen Plus” book.
– Index - Used to search for help on a topic using the index
entries
– Find - Used to search for a help on a topic that includes any
word or words
• “What’s This?” Help
– Select “What’s This?” from the Help menu and then click on
any area to get help for that item.
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Introduction to Aspen Plus
Functionality of Forms
• When you select a field on a form (click left mouse
button in the field), the prompt area at the bottom of the
window gives you information about that field.
• Click the drop-down arrow in a field to bring up a list of
possible input values for that field.
– Typing a letter will bring up the next selection on the list that
begins with that letter.
• The Tab key will take you to the next field on a form.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Basic Input
• The minimum required inputs (in addition to the graphical flowsheet)
to run a simulation are:
– Setup
– Components
– Properties
– Streams
– Blocks
• Data can be entered on input forms in the above order by clicking
the Next button.
• These inputs are all found in folders within the Data Browser.
• These input folders can be located quickly using the Data menu or
the Data Browser buttons on the toolbar.
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Introduction to Aspen Plus
Status Indicators
Symbol
Status
Input for the form is incomplete
Input for the form is complete
No input for the form has been entered. It is optional.
Results for the form exist.
Results for the form exist, but there were calculation
errors.
Results for the form exist, but there were calculation
warnings.
Results for the form exist, but input has changed since
the results were generated.
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Introduction to Aspen Plus
Cumene Production Conditions
RECYCLE
REACTOR
COOL
FEED
T = 220 F
P = 36 psia
Benzene: 40 lbmol/hr
Propylene: 40 lbmol/hr
REAC-OUT
Q = 0 Btu/hr
Pdrop = 0 psi
COOL-OUT
©2000 AspenTech. All Rights Reserved.
P = 1 atm
Q = 0 Btu/hr
T = 130 F
Pdrop = 0.1 psi
C6H6 + C3H6
= C9H12
Benzene Propylene Cumene (Isopropylbenzene)
90% Conversion of Propylene
Use the RK-SOAVE Property Method
SEP
PRODUCT
Filename: CUMENE.BKP
Introduction to Aspen Plus
Setup
• Most of the commonly used Setup information is entered
on the Setup Specifications Global sheet:
– Flowsheet title to be used on reports
– Run type
– Input and output units
– Valid phases (e.g. vapor-liquid or vapor-liquid-liquid)
– Ambient pressure
• Stream report options are located on the Setup Report
Options Stream sheet.
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Introduction to Aspen Plus
Setup Specifications Form
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Introduction to Aspen Plus
Stream Report Options
• Stream report options are located on the Setup Report
Options Stream sheet.
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Introduction to Aspen Plus
Setup Run Types
Run Type
Flowsheet
Standard Aspen Plus flowsheet run including sensitivity studies and optimization.
Flowsheet runs can contain property estimation, assay data analysis, and/or property analysis
calculations.
Assay Data
Analysis
A standalone Assay Data Analysis and pseudocomponent generation run
Data
Regression
A standalone Data Regression run
PROPERTIES
PLUS
PROPERTIES PLUS setup run
Property
Analysis
Property
Estimation
©2000 AspenTech. All Rights Reserved.
Use Assay Data Analysis to analyze assay data when you do not want to perform a flowsheet
simulation in the same run.
Use Data Regression to fit physical property model parameters required by ASPEN PLUS to
measured pure component, VLE, LLE, and other mixture data. Data Regression can contain
property estimation and property analysis calculations. ASPEN PLUS cannot perform data
regression in a Flowsheet run.
Use PROPERTIES PLUS to prepare a property package for use with Aspen Custom Modeler
(formerly SPEEDUP) or Aspen Pinch (formerly ADVENT), with third-party commercial
engineering programs, or with your company's in-house programs. You must be licensed to use
PROPERTIES PLUS.
A standalone Property Analysis run
Use Property Analysis to generate property tables, PT-envelopes, residue curve maps, and other
property reports when you do not want to perform a flowsheet simulation in the same run.
Property Analysis can contain property estimation and assay data analysis calculations.
Standalone Property Constant Estimation run
Use Property Estimation to estimate property parameters when you do not want to perform a
flowsheet simulation in the same run.
Introduction to Aspen Plus
Setup Units
• Units in Aspen Plus can be defined at 3 different levels:
1. Global Level (“Input Data” & “Output Results” fields on the
Setup Specifications Global sheet)
2. Object level (“Units” field in the top of any input form of an
object such as a block or stream
3. Field Level
• Users can create their own units sets using the Setup
Units Sets Object Manager. Units can be copied from an
existing set and then modified.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Components
• Use the Components Specifications form to specify all
the components required for the simulation.
• If available, physical property parameters for each
component are retrieved from databanks.
• Pure component databanks contain parameters such as
molecular weight, critical properties, etc. The databank
search order is specified on the Databanks sheet.
• The Find button can be used to search for components.
• The Electrolyte Wizard can be used to set up an
electrolyte simulation.
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Introduction to Aspen Plus
Components Specifications Form
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Entering Components
• The Component ID is used to identify the component in simulation
inputs and results.
• Each Component ID can be associated with a databank component
as either:
– Formula: Chemical formula of component (e.g., C6H6)
(Note that a suffix is added to formulas when there are isomers, e.g.
C2H6O-2)
– Component Name: Full name of component (e.g., BENZENE)
• Databank components can be searched for using the Find button.
– Search using component name, formula, component class, molecular
weight, boiling point, or CAS number.
– All components containing specified items will be listed.
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Introduction to Aspen Plus
Find
• Find performs an AND search when more than one
criterion is specified.
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Introduction to Aspen Plus
Pure Component Databanks
• Parameters missing from the first selected databank will be
searched for in subsequent selected databanks.
Databank Contents
Use
PURE10
Data from the Design Institute for Physical
Property Data (DIPPR) and AspenTech
Primary component databank in
Aspen Plus
AQUEOUS
Pure component parameters for ionic and
molecular species in aqueous solution
Simulations containing
electrolytes
SOLIDS
Pure component parameters for strong
electrolytes, salts, and other solids
Simulations containing
electrolytes and solids
INORGANIC Thermochemical properties for inorganic
components in vapor, liquid and solid states
Solids, electrolytes, and
metallurgy applications
PURE93
Data from the Design Institute for Physical
Property Data (DIPPR) and AspenTech
delivered with Aspen Plus 9.3
For upward compatibility
PURE856
Data from the Design Institute for Physical
Property Data (DIPPR) and AspenTech
delivered with Aspen Plus 8.5-6
For upward compatibility
ASPENPCD
Databank delivered with Aspen Plus 8.5-6
For upward compatibility
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Properties
• Use the Properties Specifications form to specify the
physical property methods to be used in the simulation.
• Property methods are a collection of models and
methods used to describe pure component and mixture
behavior.
• Choosing the right physical properties is critical for
obtaining reliable simulation results.
• Selecting a Process Type will narrow the number of
methods available.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Properties Specifications Form
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Introduction to Aspen Plus
Streams
• Use Stream Input forms to specify the feed stream
conditions and composition.
• To specify stream conditions enter two of the following:
– Temperature
– Pressure
– Vapor Fraction
• To specify stream composition enter either:
– Total stream flow and component fractions
– Individual component flows
• Specifications for streams that are not feeds to the
flowsheet are used as estimates.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Streams Input Form
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Introduction to Aspen Plus
Blocks
• Each Block Input or Block Setup form specifies operating
conditions and equipment specifications for the unit
operation model.
• Some unit operation models require additional
specification forms
• All unit operation models have optional information forms
(e.g. BlockOptions form).
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Block Form
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Introduction to Aspen Plus
Starting the Run
• Select Control Panel from the View menu or press the
Next button to be prompted.
– The simulation can be executed when all required forms are
complete.
– The Next button will take you to any incomplete forms.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Control Panel
• The Control Panel consists of:
– A message window showing the progress of the simulation by
displaying the most recent messages from the calculations
– A status area showing the hierarchy and order of simulation
blocks and convergence loops executed
– A toolbar which you can use to control the simulation
©2000 AspenTech. All Rights Reserved.
Run
Start or continue calculations
Step
Step through the flowsheet one
block at a time
Stop
Pause simulation calculations
Reinitialize
Purge simulation results
Results
Check simulation results
Introduction to Aspen Plus
Reviewing Results
• History file or Control Panel Messages
– Contains any generated errors or warnings
– Select History or Control Panel on the View menu to display the
History file or the Control Panel
• Stream Results
– Contains stream conditions and compositions
•
•
For all streams (/Data/Results Summary/Streams)
For individual streams (bring up the stream folder in the Data Browser
and select the Results form)
• Block Results
– Contains calculated block operating conditions (bring up the
block folder in the Data Browser and select the Results form)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Benzene Flowsheet Conditions Workshop
• Objective: Add the process and feed stream conditions to a
flowsheet.
– Starting with the flowsheet created in the Benzene Flowsheet
Definition Workshop (saved as BENZENE.BKP), add the process and
feed stream conditions as shown on the next page.
• Questions:
1. What is the heat duty of the block “COOL”? _________
2. What is the temperature in the second flash block “FL2”? _________
Note: Answers for all of the workshops are located in the very back of
the course notes in Appendix C.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Benzene Flowsheet Conditions Workshop
VAP1
COOL
FL1
FEED
Feed
T = 1000 F
P = 550 psia
COOL
T = 100 F
P = 500 psia
T = 200 F
Pdrop = 0
VAP2
FL2
LIQ1
P = 1 atm
Q=0
Hydrogen: 405 lbmol/hr
Methane: 95 lbmol/hr
Benzene: 95 lbmol/hr
Toluene: 5 lbmol/hr
Use the PENG-ROB Property Method
©2000 AspenTech. All Rights Reserved.
LIQ2
When finished, save as
filename: BENZENE.BKP
Introduction to Aspen Plus
Unit Operation Models
Objective:
Review major types of unit operation models
Aspen Plus References:
User Guide, Chapter 10, Unit Operation Models
Unit Operation Models Reference Manual
©2000 AspenTech. All Rights Reserved.
Unit Operation Model Types
• Mixers/Splitters
• Separators
• Heat Exchangers
• Columns
• Reactors
• Pressure Changers
• Manipulators
• Solids
• User Models
Reference: The use of specific models is best described by on-line help and the
documentation. Aspen Plus Unit Operation Models Reference Manual
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Mixers/Splitters
Model
Description
Purpose
Use
Mixer
Stream mixer
Combine multiple
streams into one
stream
Mixing tees, stream mixing
operations, adding heat
streams, adding work streams
FSplit
Stream splitter
Split stream flows
Stream splitters, bleed valves
SSplit
Substream splitter
Split substream flows
Solid stream splitters, bleed
valves
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Separators
Model
Description Purpose
Use
Flash2
Two-outlet flash Determine thermal
and phase conditions
Flashes, evaporators, knockout
drums, single stage separators,
free water separations
Flash3
Three-outlet
flash
Determine thermal
and phase conditions
Decanters, single stage separators
with two liquid phases
Decanter
Liquid-liquid
decanter
Determine thermal
and phase conditions
Decanters, single stage separators
with two liquid phases and no vapor
phase
Sep
Multi-outlet
component
separator
Separate inlet stream
components into any
number of outlet
streams
Component separation operations
such as distillation and absorption,
when the details of the separation are
unknown or unimportant
Sep2
Two-outlet
component
separator
Separate inlet stream
components into two
outlet streams
Component separation operations
such as distillation and absorption,
when the details of the separation are
unknown or unimportant
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heat Exchangers
Model
Description
Purpose
Use
Heater
Heater or cooler
Determines thermal and
phase conditions
Heaters, coolers, valves. Pumps and
compressors when work-related results are not
needed.
HeatX
Two-stream heat
exchanger
Exchange heat between two
streams
Two-stream heat exchangers. Rating shell and
tube heat exchangers when geometry is known.
MHeatX
Multistream heat
exchanger
Exchange heat between any
number of streams
Multiple hot and cold stream heat exchangers.
Two-stream heat exchangers. LNG
exchangers.
Hetran*
Interface to B-JAC
Hetran program
Design and simulate shell and
tube heat exchangers
Shell and tube heat exchangers with a wide
variety of configurations.
Aerotran*
Interface to B-JAC
Aerotran program
Design and simulate aircooled heat exchangers
Air-cooled heat exchangers with a wide variety
of configurations. Model economizers and the
convection section of fired heaters.
HXFlux
Heat transfer
calculation model
Models convective heat
transfer between a heat sink
and a heat source.
Determines the log-mean temperature
difference, using either the rigorous or the
approximate method.
HTRIIST*
Interface to the IST
heat exchanger
program from HTRI.
Design and simulate shell and
tube heat exchangers
Shell and tube heat exchangers with a wide
variety of configurations, including kettle
boilers.
*
Requires separate license
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Columns - Shortcut
Model
Description
DSTWU
Shortcut distillation Determine minimum RR,
Columns with one feed and
design
minimum stages, and either two product streams
actual RR or actual stages
by Winn-UnderwoodGilliland method.
Distl
Shortcut distillation Determine separation
rating
based on RR, stages, and
D:F ratio using Edmister
method.
Columns with one feed and
two product streams
SCFrac
Shortcut distillation Determine product
for petroleum
composition and flow,
fractionation
stages per section, duty
using fractionation indices.
Complex columns, such as
crude units and vacuum
towers
©2000 AspenTech. All Rights Reserved.
Purpose
Use
Introduction to Aspen Plus
Columns - Rigorous
Model
Description Purpose
Use
RadFrac
Rigorous
fractionation
Rigorous rating and design for single Distillation, absorbers, strippers,
columns
extractive and azeotropic distillation,
reactive distillation
MultiFrac
Rigorous
fractionation for
complex columns
Rigorous rating and design for
multiple columns of any complexity
PetroFrac
Petroleum refining Rigorous rating and design for
fractionation
petroleum refining applications
Preflash tower, atmospheric crude unit,
vacuum unit, catalytic cracker or coker
fractionator, vacuum lube fractionator,
ethylene fractionator and quench towers
BatchFrac*+
Rigorous batch
distillation
Rigorous rating calculations for
single batch columns
Ordinary azeotropic batch distillation,
3-phase, and reactive batch distillation
RateFrac*
Rate-based
distillation
Rigorous rating and design for single Distillation columns, absorbers, strippers,
and multiple columns. Based on
reactive systems, heat integrated units,
nonequilibrium calculations
petroleum applications
Extract
Liquid-liquid
extraction
Rigorous rating for liquid-liquid
extraction columns
Heat integrated columns, air separators,
absorber/stripper combinations, ethylene
primary fractionator/quench tower
combinations, petroleum refining
Liquid-liquid extraction
*
Requires separate license
+ Input language only in Version 10.0
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Reactors
Model
Description
Purpose
Use
RStoic
Stoichiometric
reactor
Stoichiometric reactor with
specified reaction extent or
conversion
Reactors where the kinetics are unknown or
unimportant but stoichiometry and extent are
known
RYield
Yield reactor
Reactor with specified yield Reactors where the stoichiometry and kinetics
are unknown or unimportant but yield
distribution is known
REquil
Equilibrium reactor
Chemical and phase
equilibrium by
stoichiometric calculations
Single- and two-phase chemical equilibrium
and simultaneous phase equilibrium
RGibbs
Equilibrium reactor
Chemical and phase
equilibrium by Gibbs
energy minimization
Chemical and/or simultaneous phase and
chemical equilibrium. Includes solid phase
equilibrium.
RCSTR
Continuous stirred
tank reactor
Continuous stirred tank
reactor
One, two, or three-phase stirred tank reactors
with kinetics reactions in the vapor or liquid
RPlug
Plug flow reactor
Plug flow reactor
One, two, or three-phase plug flow reactors with
kinetic reactions in any phase. Plug flow
reactions with external coolant.
RBatch
Batch reactor
Batch or semi-batch
reactor
Batch and semi-batch reactors where the
reaction kinetics are known
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Pressure Changers
Model Description Purpose
Use
Pump
Pump or
hydraulic
turbine
Change stream pressure when
the pressure, power requirement
or performance curve is known
Pumps and hydraulic turbines
Compr
Compressor or
turbine
Change stream pressure when
the pressure, power requirement
or performance curve is known
Polytropic compressors, polytropic
positive displacement
compressors, isentropic
compressors, isentropic turbines.
MCompr
Multi-stage
compressor or
turbine
Change stream pressure across
multiple stages with intercoolers.
Allows for liquid knockout
streams from intercoolers
Multistage polytropic compressors,
polytropic positive compressors,
isentropic compressors, isentropic
turbines.
Valve
Control valve
Determine pressure drop or
valve coefficient (CV)
Multi-phase, adiabatic flow in ball,
globe and butterfly valves
Pipe
Single-segment
pipe
Determine pressure drop and
heat transfer in single-segment
pipe or annular space
Multi-phase, one dimensional,
steady-state and fully developed
pipeline flow with fittings
Pipeline
Multi-segment
pipe
Determine pressure drop and
heat transfer in multi-segment
pipe or annular space
Multi-phase, one dimensional,
steady-state and fully developed
pipeline flow
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Manipulators
Model
Description
Purpose
Use
Mult
Stream multiplier
Multiply stream flows by
a user supplied factor
Multiply streams for scale-up or
scale-down
Dupl
Stream
duplicator
Copy a stream to any
number of outlets
Duplicate streams to look at
different scenarios in the same
flowsheet
ClChng
Stream class
changer
Change stream class
Link sections or blocks that use
different stream classes
Selector
Stream selector
Switch between different
inlet streams.
Test different flowsheet senarios
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids
Model
Description
Uses
Crystallizer
Continuous Crystallizer
Mixed suspension, mixed product removal (MSMPR)
crystallizeer used for the production of a single solid product
Crusher
Crushers
Gyratory/jaw crusher, cage mill breaker, and single or
multiple roll crushers
Screen
Screens
Solids-solids separation using screens
FabFl
Fabric filters
Gas-solids separation using fabric filters
Cyclone
Cyclones
Gas-solids separation using cyclones
VScrub
Venturi scrubbers
Gas-solids separation using venturi scrubbers
ESP
Dry electrostatic precipitators
Gas-solids separation using dry electrostatic precipitators
HyCyc
Hydrocyclones
Liquid-solids separation using hydrocyclones
CFuge
Centrifuge filters
Liquid-solids separation using centrifuge filters
Filter
Rotary vacuum filters
Liquid-solids separation using continuous rotary vacuum
filters
SWash
Single-stage solids washer
Single-stage solids washer
CCD
Counter-current decanter
Multistage washer or a counter-current decanter
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
User Models
• Proprietary models or 3-rd party software can be
included in an Aspen Plus flowsheet using a User2 unit
operation block.
• Excel Workbooks or Fortran code can be used to define
the User2 unit operation model.
• User-defined names can be associated with variables.
• Variables can be dimensioned based on other input
specifications (for example, number of components).
• Aspen Plus helper functions eliminate the need to know
the internal data structure to retrieve variables.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac
Objective:
Discuss the minimum input required for the
RadFrac fractionation model, and the use of
design specifications and stage efficiencies
Aspen Plus References:
Unit Operation Models Reference Manual, Chapter 4, Columns
©2000 AspenTech. All Rights Reserved.
RadFrac: Rigorous Multistage Separation
• Vapor-Liquid or Vapor-Liquid-Liquid phase simulation of:
– Ordinary distillation
– Absorption, reboiled absorption
– Stripping, reboiled stripping
– Azeotropic distillation
– Reactive distillation
• Configuration options:
– Any number of feeds
– Any number of side draws
– Total liquid draw off and pumparounds
– Any number of heaters
– Any number of decanters
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Flowsheet Connectivity
Vapor Distillate
Top-Stage or
Condenser Heat Duty
1
Heat (optional)
Liquid Distillate
Water Distillate (optional)
Feeds
Reflux
Products (optional)
Heat (optional)
Pumparound
Decanters
Heat (optional)
Heat (optional)
Bottom Stage or
Reboiler Heat Duty
Boil-up
Nstage
Product
Return
Heat (optional)
Bottoms
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Setup Configuration Sheet
• Specify:
– Number of stages
– Condenser and reboiler
configuration
– Two column operating
specifications
– Valid phases
– Convergence
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Setup Streams Sheet
• Specify:
– Feed stage location
– Feed stream convention
(see Help)
ABOVE-STAGE:
Vapor from feed goes to
stage above feed stage
– Liquid goes to feed stage
ON-STAGE:
Vapor & Liquid from feed
go to specified feed stage
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Feed Convention
Above-stage
(default)
n-1
On-stage
n-1
Vapor
Feed
Liquid
n
Feed
n
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Setup Pressure Sheet
• Specify one of:
– Column pressure profile
– Top/Bottom pressure
– Section pressure drop
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Methanol-Water RadFrac Column
OVHD
FEED
RadFrac specifications
Total Condenser
COLUMN
Kettle Reboiler
T = 65 C
P = 1 bar
BTMS
Water: 100 kmol/hr
Methanol: 100 kmol/hr
9 Stages
Reflux Ratio = 1
Distillate to feed ratio = 0.5
Column pressure = 1 bar
Feed stage = 6
Use the NRTL-RK Property Method
Filename: RAD-EX.BKP
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Options
• To set up an absorber with no condenser or reboiler, set
condenser and reboiler to none on the RadFrac Setup
Configuration sheet.
• Either Vaporization or Murphree efficiencies on either a
stage or component basis can be specified on the
RadFrac Efficiencies form.
• Tray and packed column design and rating is possible.
• A Second liquid phase may be modeled if the user
selects Vapor-liquid-liquid as Valid phases.
• Reboiler and condenser heat curves can be generated.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Plot Wizard
• Use Plot Wizard (on the Plot menu) to quickly generate plots of
results of a simulation. You can use Plot Wizard for displaying
results for the following operations:
– Physical property analysis
– Data regression analysis
– Profiles for all separation models RadFrac, MultiFrac, PetroFrac and
RateFrac
• Click the object of interest in the Data Browser to generate plots for
that particular object.
• The wizard guides you in the basic operations for generating a plot.
• Click on the Next button to continue. Click on the Finish button to
generate a plot with default settings.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Plot Wizard Demonstration
1
• Use the plot wizard on the column to create a plot of the
vapor phase compositions throughout the column.
Block C OLU MN : Vapor Compos ition Prof iles
WATER
Y (mole frac)
0.25
0.5
0.75
METHANOL
1
©2000 AspenTech. All Rights Reserved.
2
3
4
5
6
St age
7
8
9
Introduction to Aspen Plus
RadFrac DesignSpecs and Vary
• Design specifications can be specified and executed inside the
RadFrac block using the DesignSpecs and Vary forms.
• One or more RadFrac inputs can be manipulated to achieve
specifications on one or more RadFrac performance parameters.
• The number of specs should, in general, be equal to the number of
varies.
• The DesignSpecs and Varys in a RadFrac are solved in a “Middle
loop.” If you get an error message saying that the middle loop was
not converged, check the DesignSpecs and Varys you have entered.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence Problems
• If a RadFrac column fails to converge, doing one or more
of the following could help:
1. Check that physical property issues (choice of Property
Method, parameter availability, etc.) are properly addressed.
2. Ensure that column operating conditions are feasible.
3. If the column err/tol is decreasing fairly consistently, increase
the maximum iterations on the RadFrac Convergence Basic
sheet.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence Problems (Continued)
4. Provide temperature estimates for some stages in the
column using the RadFrac Estimates Temperature
sheet (useful for absorbers).
5. Provide composition estimates for some stages in the
column using the RadFrac Estimates Liquid
Composition and Vapor Composition sheet (useful for
highly non-ideal systems).
6. Experiment with different convergence methods on the
RadFrac Setup Configuration sheet.
Note: When a column does not converge, it is usually
beneficial to Reinitialize after making changes.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Workshop
Part A
• Perform a rating calculation of a Methanol tower using
the following data:
•
DIST
FEED
COLUMN
Feed:
63.2 wt% Water
36.8 wt% Methanol
Total flow = 120,000 lb/hr
Pressure 18 psia
Saturated liquid
Use the NRTL-RK Property Method
©2000 AspenTech. All Rights Reserved.
Column specification:
38 trays (40 stages)
Feed tray = 23 (stage 24)
Total condenser
Top stage pressure = 16.1 psia
Pressure drop per stage = 0.1 psi
Distillate flowrate = 1245 lbmol/hr
Molar reflux ratio = 1.3
BTMS
Filename: RADFRAC.BKP
Introduction to Aspen Plus
RadFrac Workshop (Continued)
Part B
• Set up design specifications within the column so the following two
objectives are met:
– 99.95 wt% methanol in the distillate
– 99.90 wt% water in the bottoms
• To achieve these specifications, you can vary the distillate rate (8001700 lbmol/hr) and the reflux ratio (0.8-2). Make sure stream
compositions are reported as mass fractions before running the
problem. Note the condenser and reboiler duties:
Condenser Duty :_________
Reboiler Duty :_________
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Workshop (Continued)
Part C
• Perform the same design calculation after specifying a
65% Murphree efficiency for each tray. Assume the
condenser and reboiler have stage efficiencies of 90%.
• How do these efficiencies affect the condenser and
reboiler duties of the column?
Part D
• Perform a tray sizing calculation for the entire column,
given that Bubble Cap trays are used.
(When finished, save as filename: RADFRAC.BKP)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Reactor Models
Objective:
Introduce the various classes of reactor models
available, and examine in some detail at least one
reactor from each class
Aspen Plus References
Unit Operation Models Reference Manual, Chapter 5, Reactors
©2000 AspenTech. All Rights Reserved.
Reactor Overview
Reactors
Balance Based
RYield
RStoic
©2000 AspenTech. All Rights Reserved.
Equilibrium Based
REquil
RGibbs
Kinetics Based
RCSTR
RPlug
RBatch
Introduction to Aspen Plus
Balanced Based Reactors
• RYield
– Requires a mass balance only, not an atom balance
– Is used to simulate reactors in which inlets to the reactor are
not completely known but outlets are known (e.g. to simulate a
furnace)
RYield
1000 lb/hr Coal
70 lb/hr H2O
20 lb/hr CO2
60 lb/hr CO
250 lb/hr tar
600 lb/hr char
IN
OUT
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Balanced Based Reactors (Continued)
• RStoic
– Requires both an atom and a mass balance
– Used in situations where both the equilibrium data and the
kinetics are either unknown or unimportant
– Can specify or calculate heat of reaction at a reference
temperature and pressure
RStoic
C, O2
IN
2 CO + O2 --> 2 CO2
C + O2 --> CO2
2 C + O2 --> 2 CO
C, O2, CO, CO2
OUT
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Equilibrium Based Reactors
• GENERAL
– Do not take reaction kinetics into account
– Solve similar problems, but problem specifications are different
– Individual reactions can be at a restricted equilibrium
• REquil
– Computes combined chemical and phase equilibrium by
solving reaction equilibrium equations
– Cannot do a 3-phase flash
– Useful when there are many components, a few known
reactions, and when relatively few components take part in the
reactions
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Equilibrium Based Reactors (Continued)
• RGibbs
– Unknown Reactions - This feature is quite useful when
reactions occurring are not known or are high in number due to
many components participating in the reactions.
– Gibbs Energy Minimization - A Gibbs free energy
minimization is done to determine the product composition at
which the Gibbs free energy of the products is at a minimum.
– Solid Equilibrium - RGibbs is the only Aspen Plus block that
will deal with solid-liquid-gas phase equilibrium.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Kinetic Reactors
• Kinetic reactors are RCSTR, RPlug and RBatch.
• Reaction kinetics are taken into account, and hence must be
specified.
• Kinetics can be specified using one of the built-in models, or with a
user subroutine. The current built-in models are
– Power Law
– Langmuir-Hinshelwood-Hougen-Watson (LHHW)
• A catalyst for a reaction can have a reaction coefficient of zero.
• Reactions are specified using a Reaction ID.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Using a Reaction ID
• Reaction IDs are setup as objects, separate from the
reactor, and then referenced within the reactor(s).
• A single Reaction ID can be referenced in any number of
kinetic reactors (RCSTR, RPlug and RBatch.)
• To set up a Reaction ID, go to the Reactions Reactions
Object Manager
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Power-law Rate Expression
rate  k *  [concentrationi ]exponent i
i
 Activation Energy  1 1  
T 
k  (Pre  exponentia l Factor)   exp  
   
R
 T0 
 T T0  

n
 C  2 D
2 A  3B 

k 2
k1
Example:
Forward reaction: (Assuming the reaction is 2nd order in A)
coefficients:
A: -2
B: -3
C: 1
D: 2
exponents:
A: 2
B: 0
C: 0
D: 0
Reverse reaction: (Assuming the reaction is 1st order in C and D)
coefficients:
C: -1 D: -2
A: 2 B: 3
exponents:
C: 1 D: 1
A: 0 B: 0
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heats of Reaction
• Heats of reaction need not be provided for reactions.
• Heats of reaction are typically calculated as the
difference between inlet and outlet enthalpies for the
reactor (see Appendix A).
• If you have a heat of reaction value that does not match
the value calculated by Aspen Plus, you can adjust the
heats of formation (DHFORM) of one or more
components to make the heats of reaction match.
• Heats of reaction can also be calculated or specified at a
reference temperature and pressure in an RStoic reactor.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Reactor Workshop
• Objective - Compare the use of different reactor types to model
one reaction.
• Reactor Conditions:
Temperature = 70 C
Pressure = 1 atm
• Stoichiometry:
Ethanol + Acetic Acid <--> Ethyl Acetate + Water
• Kinetic Parameters:
– Forward Reaction: Pre-exp. Factor = 1.9 x 108, Act. Energy = 5.95 x 107 J/kmol
– Reverse Reaction: Pre-exp. Factor = 5.0 x 107, Act. Energy = 5.95 x 107 J/kmol
– Reactions are first order with respect to each of the reactants in the reaction (second
order overall).
– Reactions occur in the liquid phase.
– Composition basis is Molarity.
Hint: Check that each reactor is considering both Vapor and Liquid as Valid
phases.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Reactor Workshop (Continued)
Use the NRTL-RK
property method
P-STOIC
RSTOIC
F-STOIC
FEED
Feed:
Temp = 70 C
DUPL
Pres = 1 atm
Water: 8.892 kmol/hr
Ethanol: 186.59 kmol/hr
Acetic Acid: 192.6 kmol/hr
70 % conversion of ethanol
F-GIBBS
P-GIBBS
RGIBBS
F-PLUG
P-PLUG
RPLUG
F-CSTR
P-CSTR
When finished, save as
filename: REACTORS.BKP
RCSTR
©2000 AspenTech. All Rights Reserved.
Length = 2 meters
Diameter = 0.3 meters
Volume = 0.14 Cu. M.
Introduction to Aspen Plus
Cyclohexane Production Workshop
• Objective - Create a flowsheet to model a cyclohexane production
process
• Cyclohexane can be produced by the hydrogenation of benzene in the
following reaction:
C6H6
Benzene
+
3 H2
=
Hydrogen
C6H12
Cyclohexane
• The benzene and hydrogen feeds are combined with recycle hydrogen and
cyclohexane before entering a fixed bed catalytic reactor. Assume a
benzene conversion of 99.8%.
• The reactor effluent is cooled and the light gases separated from the
product stream. Part of the light gas stream is fed back to the reactor as
recycle hydrogen.
• The liquid product stream from the separator is fed to a distillation column to
further remove any dissolved light gases and to stabilize the end product. A
portion of the cyclohexane product is recycled to the reactor to aid in
temperature control.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Cyclohexane Production Workshop
C6H6
+ 3 H2
=
C6H12
Benzene
Hydrogen
Cyclohexane
Total flow = 330 kmol/hr
92% flow to stream H2RCY
T = 50 C
P = 25 bar
Molefrac H2 = 0.975
N2 = 0.005
CH4 = 0.02
H2IN
PURGE
VFLOW
H2RCY
VAP
FEED-MIX
REACT
RXIN
BZIN
T = 150C
P = 23 bar
T = 40 C
P = 1 bar
Benzene flow = 100 kmol/hr
HP-SEP
RXOUT
T = 200 C
Pdrop = 1 bar
Benzene conv =
0.998
LTENDS
T = 50 C
Pdrop = 0.5 bar
Theoretical Stages = 12
Reflux ratio = 1.2
Bottoms rate = 99 kmol/hr
Partial Condenser with
vapor distillate only
Column Pressure = 15 bar
Feed stage = 8
LIQ
CHRCY
COLFD
LFLOW
30% flow to stream CHRCY
Use the RK-SOAVE property method
When finished, save as
filename: CYCLOHEX.BKP
©2000 AspenTech. All Rights Reserved.
PRODUCT
COLUMN
Specify cyclohexane mole
recovery in PRODUCT stream
equal to 0.9999 by varying
Bottoms rate from 97 to 101 kmol/hr
Introduction to Aspen Plus
Physical Properties
Objectives:
Introduce the ideas of property methods and physical property parameters
Identify issues involved in the choice of a property method
Cover the use of Property Analysis for reporting physical properties
Aspen Plus References:
User Guide, Chapter 7, Physical Property Methods
User Guide, Chapter 8, Physical Property Parameters and Data
User Guide, Chapter 29, Analyzing Properties
©2000 AspenTech. All Rights Reserved.
Case Study - Acetone Recovery
• Correct choice of physical property models and accurate physical
property parameters are essential for obtaining accurate simulation
results.
OVHD
COLUMN
FEED
5000 lbmol/hr
10 mole % acetone
90 mole % water
BTMS
Specification: 99.5 mole % acetone recovery
Predicted number of
stages required
Approximate cost in dollars
©2000 AspenTech. All Rights Reserved.
Ideal
Equation of
Activity Coefficient
Approach
State Approach
Model Approach
11
7
42
520, 000
390, 000
880, 000
Introduction to Aspen Plus
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Property Methods
• A Property Method is a collection of models and methods
used to calculate physical properties.
• Property Methods containing commonly used
thermodynamic models are provided in Aspen Plus.
• Users can modify existing Property Methods or create
new ones.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Physical Property Models
• Approaches to representing physical properties of
components
Physical Property Models
Ideal
Equation of State
Activity
Special
(EOS)
Coefficient
Models
Models
Models
• Choice of model types depends on degree of non-ideal
behavior and operating conditions.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Ideal vs. Non-Ideal Behavior
• What do we mean by ideal behavior?
y
– Ideal Gas law and Raoult’s law
x
• Which systems behave as ideal?
– Non-polar components of similar size and shape
• What controls degree of non-ideality?
– Molecular interactions
e.g. Polarity, size and shape of the molecules
• How can we study the degree of non-ideality of a
system?
– Property plots (e.g. TXY & XY)
y
y
x
©2000 AspenTech. All Rights Reserved.
x
Introduction to Aspen Plus
Comparison of EOS and Activity Models
EOS Models
Activity Coefficient Models
Limited in ability to represent
non-ideal liquids
Can represent highly non-ideal liquids
Fewer binary parameters
required
Many binary parameters required
Parameters extrapolate
reasonably with temperature
Binary parameters are highly
temperature dependent
Consistent in critical region
Inconsistent in critical region
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Common Property Methods
• Equation of State Property Methods
– PENG-ROB
– RK-SOAVE
• Activity Coefficient Property Methods
– NRTL
– UNIFAC
– UNIQUAC
– WILSON
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Henry's Law
• Henry's Law is only used with ideal and activity
coefficient models.
• It is used to determine the amount of a supercritical
component or light gas in the liquid phase.
• Any supercritical components or light gases (CO2, N2,
etc.) should be declared as Henry's components
(Components Henry Comps Selection sheet).
• The Henry's components list ID should be entered on
Properties Specifications Global sheet in the Henry
Components field.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Choosing a Property Method - Review
Do you have any polar
components in your system?
N
Y
Use EOS Model
Y
Are the operating conditions
near the critical region of the
mixture?
N
Do you have light gases or
supercritical components
in your system?
Y
References:
Aspen Plus User Guide, Chapter 7, Physical Property Methods,
gives similar, more detailed guidelines for choosing a
property Method.
©2000 AspenTech. All Rights Reserved.
Use activity
coefficient model
with Henry’s Law
N
Use activity
coefficient
model
Introduction to Aspen Plus
Choosing a Property Method - Example
System
Model Type
Property Method
Propane, Ethane, Butane
EOS
RK-SOAVE, PENG-ROB
Benzene, Water
Activity Coefficient
NRTL-RK, UNIQUAC
Acetone, Water
Activity Coefficient
NRTL-RK, WILSON
• Choose an appropriate Property Method for the following
systems of components at ambient conditions.
System
Property Method
Ethanol, Water
Benzene, Toluene
Acetone, Water, Carbon Dioxide
Water, Cyclohexane
Ethane and Propanol
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Pure Component Parameters
• Represent attributes of a single component
• Input in the Properties Parameters Pure Component folder.
• Stored in databanks such as PURE10, ASPENPCD, SOLIDS, etc.
(The selected databanks are listed on the Components
Specifications Databanks sheet.)
• Parameters retrieved into the Graphical User Interface by selecting
Retrieve Parameter Results from the tools menu.
• Examples
– Scalar: MW for molecular weight
– Temperature-Dependent: PLXANT for parameters in the extended
Antoine vapor pressure model
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Binary Parameters
• Used to describe interactions between two components
• Input in the Properties Parameters Binary Interaction folder
• Stored in binary databanks such as VLE-IG, LLE-ASPEN
• Parameter values from the databanks can be viewed on the input
forms in the Graphical User Interface.
• Parameter forms that include data from the databanks must be
viewed before the flowsheet is complete.
• Examples
– Scalar: RKTKIJ for the Rackett model
– Temperature-Dependent: NRTL for parameters in the NRTL model
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Displaying Property Parameters
• Aspen Plus does not display all databank parameters on
the parameter input forms.
• Select Retrieve Parameter Results from the Tools menu
to retrieve all parameters for the components and
property methods defined in the simulation.
• All results that are currently loaded will be lost. They can
be regenerated by running the simulation again.
• The parameters are viewed on the Properties
Parameters Results forms.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Reporting Parameters
• To get a Report of the retrieved parameters in a text file.
– Select Retrieve Parameter Results from the Tools menu,
– Select Report from the View menu.
– Select display report for Simulation and click Ok.
PHYSICAL PROPERTIES SECTION
PROPERTY PARAMETERS
------------------PARAMETERS ACTUALLY USED IN THE SIMULATION
PURE COMPONENT PARAMETERS
------------------------COMPONENT ID: BENZENE
FORMULA: C6H6
NAME: C6H6
SCALAR PARAMETERS
----------------PARAM
NAME
©2000 AspenTech. All Rights Reserved.
SET DESCRIPTIONS
NO.
VALUE
UNITS
28.500
SOURCE
API
1
STANDARD API GRAVITY
CHARGE
1
IONIC CHARGE
0.00000E+00
AQUEOUS
CHI
1
STIEL POLAR FACTOR
0.00000E+00
DEFAULT
DCPLS
1
DIFFERENCE BETWEEN LIQUID AND
SOLID CP AT TRIPLE POINT
0.31942
DGFORM
1
IDEAL GAS GIBBS ENERGY
OF FORMATION
30.954
PURE10
CAL/MOL-K
PURE10
KCAL/MOL
PURE10
Introduction to Aspen Plus
Reporting Physical Property Parameters
• Follow this procedure to obtain a report file containing
values of ALL pure component and binary parameters for
ALL components used in a simulation:
1. On the Setup Report Options Property sheet,
select All physical property parameters used (in SI units) or
select Property parameters’ descriptions, equations, and
sources of data.
2. After running the simulation, export a report (*.rep) file (Select
Export from the File menu).
3. Edit the .rep file using any text editor. (From the Graphical
User Interface, you can choose Report from the View menu.)
The parameters are listed under the heading PARAMETER
VALUES in the physical properties section of the report file.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Property Analysis
• Used to generate simple property diagrams to validate physical property
models and data
• Diagram Types:
– Pure component, e.g. Vapor pressure vs. temperature
– Binary, e.g. TXY, PXY
– Ternary residue maps
• Select Analysis from the Tools menu to start Analysis.
• Additional binary plots are available under the Plot Wizard button on result
form containing raw data.
• When using a binary analysis to check for liquid-liquid phase separation,
remember to choose Vapor-Liquid-Liquid as Valid phases.
• Property analysis input and results can be saved as a form for later
reference and use.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Property Analysis - Common Plots
Ideal XY Plot:
XY Plot Showing Azeotrope:
y-x diagram for METHANOL / PROPANOL
y-x diagram for ETHANOL / TOLUENE
(PRES = 14.7 PSI)
0
(PRES = 14.7 PSI)
0.2
0.4
0.6
0.8
1
LIQUID MOLEFRAC METHANOL
0
0.2
0.4
0.6
0.8
1
LIQUID MOLEFRAC ETHANOL
XY Plot Showing 2 liquid phases:
y-x diagram for TOLUENE / WATER
(PRES = 14.7 PSI)
©2000 AspenTech. All Rights Reserved.
0
0.2
0.4
0.6
0.8
1
LIQUID MOLEFRAC TOLUENE
Introduction to Aspen Plus
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Establishing Physical Properties - Review
1. Choose Property Method - Select a Property Method based on
– Components present in simulation
– Operating conditions in simulation
– Available data or parameters for the components
2. Check Parameters - Determine parameters available in Aspen Plus
databanks
3. Obtain Additional Parameters (if necessary) - Parameters that are needed
can be obtained from
– Literature searches (DETHERM, etc.)
– Regression of experimental data (Data Regression)
– Property Constant Estimation (Property Estimation)
4. Confirm Results - Verify choice of Property Method and physical property
data using
– Physical Property Analysis
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Property Sets
• A property set (Prop-Set) is a way of accessing a collection, or set,
of properties as an object with a user-given name. Only the name of
the property set is referenced when using the properties in an
application.
• Use property sets to report thermodynamic, transport, and other
property values.
• Current property set applications include:
– Design specifications, Fortran blocks, sensitivity
– Stream reports
– Physical property tables (Property Analysis)
– Tray properties (RadFrac, MultiFrac, etc.)
– Heating/cooling curves (Flash2, MHeatX, etc.)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Properties included in Prop-Sets
• Properties commonly included in property sets include:
–
–
–
–
VFRAC
BETA
CPMX
MUMX
-
Molar vapor fraction of a stream
Fraction of liquid in a second liquid phase
Constant pressure heat capacity for a mixture
Viscosity for a mixture
• Available properties include:
– Thermodynamic properties of components in a mixture
– Pure component thermodynamic properties
– Transport properties
– Electrolyte properties
– Petroleum-related properties
Reference: Aspen Plus Physical Property Data Reference Manual, Chapter 4, Property Sets, has a
complete list of properties that can be included in a property set.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Specifying Property Sets
• Use the Properties Prop-Sets form to specify properties in a property set.
• The Search button can be used to search for a property.
• All specified qualifiers apply to each property specified, where
applicable.
• Users can define new properties on the Properties Advanced UserProperties form by providing a Fortran subroutine.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Predefined Property Sets
• Some simulation Templates contain predefined property
sets.
• The following table lists predefined property sets and the
types of properties they contain for the General
Template:
©2000 AspenTech. All Rights Reserved.
Predefined Property Set
Types of Properties
HXDESIGN
Heat exchanger design
THERMAL
Mixture thermal (HMX, CPMX,
KMX)
TXPORT
Transport
VLE
Vapor-liquid equilibrium
(PHIMX, GAMMA, PL)
VLLE
Vapor-liquid-liquid equilibrium
Introduction to Aspen Plus
Stream Results Options
• On the Setup Report Options Stream sheet, use:
– Flow Basis and Fraction Basis check-boxes to specify how
stream composition is reported
– Property Sets button to specify names of property sets
containing additional properties to be reported for each stream
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Definition of Terms
• Property Method - Set of property models and methods
used to calculate the properties required for a simulation
• Property - Calculated physical property value such as
mixture enthalpy
• Property Model - Equation or equations used to
calculate a physical property
• Property Parameter - Constant used in a property
model
• Property Set (Prop-Set) - A method of accessing
properties so that they can be used or tabulated
elsewhere
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Aspen Properties
• Aspen Properties is now a stand-alone product.
• In addition to the standard property features available in
Aspen Plus, Aspen Properties includes:
– Excel Interface
– Web Interface
• Excel Interface is an Excel Add-In that has Excel
functions to do property calculations such as:
– Flash at a given set of conditions
– Calculate a property such as density or viscosity
• Web Interface is currently only available for pure
components.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Physical Properties Workshop
• Objective: Simulate a two-liquid phase settling tank and
investigate the physical properties of the system.
• A refinery has a settling tank that they use to decant off the water
from a mixture of water and a heavy oil. The inlet stream to the tank
also contains some carbon-dioxide and nitrogen. The tank and feed
are at ambient temperature and pressure (70o F, 1atm), and have
the following flow rates of the various components:
Water
515 lb/hr
Oil
CO2
4322 lb/hr
751 lb/hr
N2
43 lb/hr
• Use the compound n-decane to represent the oil. It is known that
water and oil form two liquid phases under the conditions in the tank.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Physical Properties Workshop (Continued)
1. Choose an appropriate Property Method to represent this system.
Check to see that the required binary physical property parameters
are available.
2. Retrieve the physical property parameters used in the simulation and
determine the critical temperature for carbon dioxide and water.
TC(carbon dioxide) = _______; TC(water) = _______
3. Using the property analysis feature, verify that the chosen physical
property model and the available parameters predict the formation of
2 liquid phases.
4. Set up a simulation to model the settling tank. Use a Flash3 block to
represent the tank.
5. Modify the stream report to include the constant pressure heat
capacity (CPMX) for each phase (Vapor, 1st Liquid and 2nd Liquid),
and the fraction of liquid in a second liquid phase (BETA), for all
streams.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Physical Properties Workshop (Continued)
This Portion is Optional
• Objective: Generate a table of compositions for each liquid
phase (1st Liquid and 2nd Liquid) at different temperatures for
a mixture of water and oil. Tabulate the vapor pressure of the
components in the same table.
• In addition to the interactive Analysis commands under the Tools
menu, you also can create a Property Analysis manually, using
forms.
• Manually generated Generic Property Analysis is similar to the
interactive Analysis commands, however it is more flexible regarding
input and reporting.
Detailed instructions are on the following slide.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Physical Properties Workshop (Continued)
• Problem Specifications:
1. Create a Generic type property analysis from the Properties/Analysis
Object manager.
2. Generate points along a flash curve.
3. Define component flows of 50 mole water and 50 mole oil.
4. Set Valid phases to Vapor-liquid-liquid.
5. Click on the Range/List button, and vary temperature from 50 to 400 F.
6. Use a vapor fraction of zero.
7. Tabulate a new property set that includes:
a.
b.
c.
d.
Mole fraction of water and oil in the 1st and 2nd liquid phases (MOLEFRAC)
Mole flow of water and oil in the 1st and 2nd liquid phases (MOLEFLOW)
Beta - the fraction of the 1st liquid to the total liquid (BETA)
Pure component vapor pressures of water and oil (PL)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Accessing Variables
Objective:
Become familiar with referencing flowsheet
variables
Aspen Plus References:
User Guide, Chapter 18, Accessing Flowsheet Variables
Related Topics:
User Guide, Chapter 20, Sensitivity
User Guide, Chapter 21, Design Specifications
User Guide, Chapter 19, Calculator Blocks and In-Line Fortran
User Guide, Chapter 22, Optimization
User Guide, Chapter 23, Fitting a Simulation Model to Data
©2000 AspenTech. All Rights Reserved.
Why Access Variables?
OVHD
FEED
COLUMN
BTMS
• What is the effect of the reflux ratio of the column on the purity (mole
fraction of component B) of the distillate?
• To perform this analysis, references must be made to 2 flowsheet
quantities, i.e. 2 flowsheet variables must be accessed:
1. The reflux ratio of the column
2. The mole fraction of component B in the stream OVHD
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Accessing Variables
• An accessed variable is a reference to a particular
flowsheet quantity, e.g. temperature of a stream or duty
of a block.
• Accessed variables can be input, results, or both.
• Flowsheet result variables (calculated quantities) should
not be overwritten or varied.
• The concept of accessing variables is used in sensitivity
analyses, design specifications, calculator blocks,
optimization, etc.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Variable Categories
Variable Category
Type of Variable
Blocks
Block variables and vectors
Streams
Stream variables and vectors.
Both non-component variables and
component dependent flow and composition
variables can be accessed.
Model Utility
Parameters, balance block and pressure
relief variables
Property
Property parameters
Reactions
Reactions and chemistry variables
Costing
Costing variables
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Variable Definition Dialog Box
• When completing a Define sheet, such as on a Calculator, Design
specification or Sensitivity form, specify the variables on the Variable
Definition dialog box.
• You cannot modify the variables on the Define sheet itself.
• On the Variable Definition dialog box, select the variable category
and Aspen Plus will display the other fields necessary to complete
the variable definition.
• If you are editing an existing variable and want to change the
variable name, click the right mouse button on the Variable Name
field. On the popup menu, click Rename.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Notes
1. If the Mass-Frac, Mole-Frac or StdVol-Frac of a component in a
stream is accessed, it should not be modified. To modify the
composition of a stream, access and modify the Mass-Flow, MoleFlow or StdVol-Flow of the desired component.
2. If duty is specified for a block, that duty can be read and written
using the variable DUTY for that block. If the duty for a block is
calculated during simulation, it should be read using the variable
QCALC.
3. PRES is the specified pressure or pressure drop, and PDROP is
pressure drop used in calculating pressure profile in heating or
cooling curves.
4. Only streams that are feeds to the flowsheet should be varied or
modified directly.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Sensitivity Analysis
Objective:
Introduce the use of sensitivity analysis to study
relationships between process variables
Aspen Plus References:
User Guide, Chapter 20, Sensitivity
Related Topics:
User Guide, Chapter 18, Accessing Flowsheet Variables
User Guide, Chapter 19, Calculator Blocks and In-Line Fortran
©2000 AspenTech. All Rights Reserved.
Sensitivity Analysis
• Allows user to study the effect of changes in input
variables on process outputs.
• Results can be viewed by looking at the Results form in
the folder for the Sensitivity block.
• Results may be graphed to easily visualize relationships
between different variables.
• Changes made to a flowsheet input quantity in a
sensitivity block do not affect the simulation. The
sensitivity study is run independently of the base-case
simulation.
• Located under /Data/Model Analysis Tools/Sensitivity
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Sensitivity Analysis Example
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
COOL-OUT
SEP
Filename: CUMENE-S.BKP
PRODUCT
• What is the effect of cooler outlet temperature on the purity of the
product stream?
» Cooler outlet temperature
• What is the manipulated (varied) variable?
» Purity (mole fraction) of cumene in product stream
• What is the measured (sampled) variable?
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Sensitivity Analysis Results
CUMENE PRODUCT PURITY
0.85
0.9
0.95
1
• What is happening below 75 F and above 300 F?
50
©2000 AspenTech. All Rights Reserved.
Sensitivity S-1 Results Summary
75 100 125 150 175 200 225 250 275 300 325 350
VARY 1 COOL PARAM TEMP F
Introduction to Aspen Plus
Uses of Sensitivity Analysis
• Studying the effect of changes in input variables on
process (model) outputs
• Graphically representing the effects of input variables
• Verifying that a solution to a design specification is
feasible
• Rudimentary optimization
• Studying time varying variables using a quasi-steadystate approach
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Sensitivity Analysis
1. Specify measured (sampled) variable(s)
– These are quantities calculated during the simulation to be used in
step 4 (Sensitivity Input Define sheet).
2. Specify manipulated (varied) variable(s)
– These are the flowsheet variables to be varied (Sensitivity Input
Vary sheet).
3. Specify range(s) for manipulated (varied) variable(s)
– Variation for manipulated variable can be specified either as
equidistant points within an interval or as a list of values for the
variable (Sensitivity Input Vary sheet).
4. Specify quantities to calculate and tabulate
– Tabulated quantities can be any valid Fortran expression containing
variables defined in step 1 (Sensitivity Input Tabulate sheet).
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Plotting
1. Select the column containing the X-axis variable and
then select X-Axis Variable from the Plot menu.
2. Select the column containing the Y-axis variable and
then select Y-Axis Variable from the Plot menu.
3. (Optional) Select the column containing the parametric
variable and then select Parametric Variable from the
Plot menu.
4. Select Display Plot from the Plot menu.
Note: To select a column, click on the heading of the
column with the left mouse button.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Notes
1. Only quantities that have been input to the flowsheet
should be varied or manipulated.
2. Multiple inputs can be varied.
3. The simulation is run for every combination of
manipulated (varied) variables.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Sensitivity Analysis Workshop
• Objective: Use a sensitivity analysis to study the effect of the recycle
flowrate on the reactor duty in the cyclohexane flowsheet
• Part A
– Using the cyclohexane production flowsheet Workshop (saved as
CYCLOHEX.BKP), plot the variation of reactor duty (block REACT) as the
recycle split fraction in LFLOW is varied from 0.1 to 0.4.
• Optional Part B
– In addition to the fraction split off as recycle (Part A), vary the conversion of
benzene in the reactor from 0.9 to 1.0. Tabulate the reactor duty and
construct a parametric plot showing the dependence of reactor duty on the
fraction split off as recycle and conversion of benzene.
Note: Both of these studies (parts A and B) should be set up within the same
sensitivity analysis block.
• When finished, save as filename: SENS.BKP.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Cyclohexane Production Workshop
C6H6
+ 3 H2
=
C6H12
Benzene
Hydrogen
Cyclohexane
PURGE
Total flow = 330 kmol/hr
92% flow to stream H2RCY
T = 50 C
P = 25 bar
Molefrac H2 = 0.975
N2 = 0.005
CH4 = 0.02
H2IN
VFLOW
H2RCY
VAP
FEED-MIX
REACT
RXIN
BZIN
T = 40 C
P = 1 bar
Benzene flow = 100 kmol/hr
T = 150C
P = 23 bar
HP-SEP
T = 200 C
Pdrop = 1 bar
Benzene conv =
0.998
LTENDS
T = 50 C
Pdrop = 0.5 bar
RXOUT
Theoretical Stages = 12
Reflux ratio = 1.2
Bottoms rate = 99 kmol/hr
Partial Condenser with
vapor distillate only
Column Pressure = 15 bar
Feed stage = 8
LIQ
CHRCY
COLFD
LFLOW
30% flow to stream CHRCY
Use the RK-SOAVE property method
PRODUCT
COLUMN
Specify cyclohexane mole
recovery of 0.9999 by varying
Bottoms rate from 97 to 101 kmol/hr
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Design Specifications
Objective:
Introduce the use of design specifications to meet
process design requirements
Aspen Plus References
User Guide, Chapter 21, Design Specifications
Related Topics
User Guide, Chapter 18, Accessing Flowsheet Variables
User Guide, Chapter 19, Calculator Blocks and In-Line Fortran
User Guide, Chapter 17, Convergence
©2000 AspenTech. All Rights Reserved.
Design Specifications
• Similar to a feedback controller
• Allows user to set the value of a calculated flowsheet
quantity to a particular value
• Objective is achieved by manipulating a specified input
variable
• No results associated directly with a design specification
• Located under /Data/Flowsheeting Options/Design
Specs
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Design Specification Example
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
COOL-OUT
SEP
Filename: CUMENE-D.BKP
PRODUCT
• What should the cooler outlet temperature be to achieve a cumene
product purity of 98 mole percent?
» Cooler outlet temperature
•
What is the manipulated (varied) variable?
» Mole fraction of cumene in stream PRODUCT
•
What is the measured (sampled) variable?
» Mole fraction of cumene in stream PRODUCT = 0.98
•
What is the specification (target) to be achieved?
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Design Specifications
1. Identify measured (sampled) variables
– These are flowsheet quantities, usually calculated quantities, to be
included in the objective function (Design Spec Define sheet).
2. Specify objective function (Spec) and goal (Target)
– This is the equation that the specification attempts to satisfy
(Design Spec Spec sheet). The units of the variable used in the
objective function are the units for that type of variable as specified
by the Units Set declared for the design specification.
3. Set tolerance for objective function
– The specification is said to be converged if the objective function
equation is satisfied to within this tolerance (Design Spec Spec
sheet).
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Design Specifications (Continued)
4. Specify manipulated (varied) variable
– This is the variable whose value the specification changes in
order to satisfy the objective function equation (Design Spec
Vary sheet).
5. Specify range of manipulated (varied) variable
– These are the lower and upper bounds of the interval within
which Aspen Plus will vary the manipulated variable (Design
Spec Vary sheet). The units of the limits for the varied
variable are the units for that type of variable as specified by
the Units Set declared for the design specification.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Notes
1. Only quantities that have been input to the flowsheet should be
manipulated.
2. The calculations performed by a design specification are iterative.
Providing a good estimate for the manipulated variable will help the
design specification converge in fewer iterations. This is especially
important for large flowsheets with several interrelated design
specifications.
3. The results of a design specification can be found under
Data/Convergence/Convergence, by opening the appropriate
solver block, and choosing the Results form. Alternatively, the final
values of the manipulated and/or sampled variables can be viewed
directly on the appropriate Stream/Block results forms.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Notes (Continued)
4. If a design-spec does not converge:
a. Check to see that the manipulated variable is not at its lower
or upper bound.
b. Verify that a solution exists within the bounds specified for
the manipulated variable, perhaps by performing a
sensitivity analysis.
c. Check to ensure that the manipulated variable does indeed
affect the value of the sampled variables.
d. Try providing a better starting estimate for the value of the
manipulated variable.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Notes (Continued)
e. Try narrowing the bounds of the manipulated variable or
loosening the tolerance on the objective function to help
convergence.
f. Make sure that the objective function does not have a flat
region within the range of the manipulated variable.
g. Try changing the characteristics of the convergence block
associated with the design-spec (step size, number of
iterations, algorithm, etc.)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Design Specification Workshop
• Objective: Use a design specification in the cyclohexane
flowsheet to fix the heat load on the reactor by varying the
recycle flowrate.
• The cyclohexane production flowsheet workshop (saved as
CYCLOHEX.BKP) is a model of an existing plant. The cooling
system around the reactor can handle a maximum operating load of
4.7 MMkcal/hr. Determine the amount of cyclohexane recycle
necessary to keep the cooling load on the reactor to this amount.
Note: The heat convention used in Aspen Plus is that heat input to a
block is positive, and heat removed from a block is negative.
• When finished, save as filename: DES-SPEC.BKP
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Cyclohexane Production Workshop
C6H6
+ 3 H2
=
C6H12
Benzene
Hydrogen
Cyclohexane
PURGE
Total flow = 330 kmol/hr
92% flow to stream H2RCY
T = 50 C
P = 25 bar
Molefrac H2 = 0.975
N2 = 0.005
CH4 = 0.02
H2IN
VFLOW
H2RCY
VAP
FEED-MIX
REACT
RXIN
HP-SEP
LTENDS
BZIN
T = 40 C
P = 1 bar
Benzene flow = 100 kmol/hr
T = 150C
P = 23 bar
T = 50 C
Pdrop = 0.5 bar
RXOUT
T = 200 C
Pdrop = 1 bar
Benzene conv =
0.998
Theoretical Stages = 12
Reflux ratio = 1.2
Bottoms rate = 99 kmol/hr
Partial Condenser with
vapor distillate only
Column Pressure = 15 bar
Feed stage = 8
LIQ
CHRCY
COLFD
LFLOW
30% flow to stream CHRCY
Use the RK-SOAVE property method
PRODUCT
COLUMN
Specify cyclohexane mole
recovery of 0.9999 by varying
Bottoms rate from 97 to 101 kmol/hr
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Calculator Blocks
Objective:
Introduce usage of Excel and Fortran Calculator blocks
Aspen Plus References:
User Guide, Chapter 19, Calculator Blocks and In-Line Fortran
Related Topics:
User Guide, Chapter 20, Sensitivity
User Guide, Chapter 21, Design Specifications
User Guide, Chapter 18, Accessing Flowsheet Variables
User Guide, Chapter 22, Optimization
©2000 AspenTech. All Rights Reserved.
Calculator Blocks
• Allows user to write equations in an Excel spreadsheet
or in Fortran to be executed by Aspen Plus
• Results of the execution of a Calculator block must be
viewed by directly examining the values of the variables
modified by the Calculator block.
• Increasing the diagnostics for the Calculator block will
print the value of all input and result variables in the
Control Panel.
• Located under /Data/Flowsheeting Options/Calculator
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Calculator Block Example
• Use of a Calculator block to set the pressure drop across
a Heater block.
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
V
COOL-OUT
DELTA-P
Calculator Block
DELTA-P = -10-9 * V2
SEP
PRODUCT
Filename: CUMENE-F.BKP
or CUMENE-EXCEL.BKP
• Pressure drop across heater is proportional to square of
volumetric flow into heater.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Calculator Block Example (Continued)
• Which flowsheet variables must be accessed?
» Volumetric flow of stream REAC-OUT
This can be accessed in two different ways:
1. Mass flow and mass density of stream REAC-OUT
2. A prop-set containing volumetric flow of a mixture
» Pressure drop across block COOL
• When should the Calculator block be executed?
» Before block COOL
• Which variables are imported and which are exported?
» Volumetric flow is imported
» Pressure drop is exported
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Excel
Aspen Plus toolbar in Excel
Connect Current Cell
to a Defined Variable
Import Variables
=FLOW/DENS
=(-10^-9)*B6^2
Export Variable
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Calculator Blocks
1. Access flowsheet variables to be used within Calculator
– All flowsheet quantities that must be either read from or written
to, must be identified (Calculator Input Define sheet).
2. Write Fortran or Excel
– Fortran includes both non-executable (COMMON,
EQUIVALENCE, etc) Fortran (click on the Fortran Declarations
button) and executable Fortran (Calculator Input Calculate
sheet) to achieve desired result.
3. Specify location of Calculator block in execution
sequence (Calculator Input Sequence sheet)
– Specify directly, or
– Specify with import and export variables
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Uses of Calculator Blocks
• Feed-forward control (setting flowsheet inputs based on
upstream calculated values)
• Calling external subroutines
• Input / output to and from external files
• Writing to an external file, or the Control Panel, History
File, or Report File
• Custom reports
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Increasing Diagnostics
Increase Calculator defined
variables Diagnostics message level
in Control Panel or History file to 8.
Calculator Block F-1
In the Control Panel
or History File
VALUES OF ACCESSED VARIABLES
VARIABLE
VALUE
========
=====
DP
-2.032782930000
FLOW
5428.501858128
DENS
0.1204020367004
RETURNED VALUES OF VARIABLES
VARIABLE
VALUE
========
=====
DP
-2.032790410000
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Excel
• Excel workbook is embedded into simulation for each
Calculator block.
• When saving as a backup (.bkp file), a .apmbd file is
created. This file needs to be in the working directory.
• Full functionality of Excel is available including VBA and
Macros.
• Cells that contain Import variables have a green border.
Cells that contain Export variables have a blue border.
Cells that contain Tear variables have an orange border.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Excel (Continued)
• Variables can be defined in Aspen Plus on the Define
sheet or in Excel using the Aspen Plus toolbar. (It is
generally faster to add variables inside Aspen Plus.)
• No Fortran compiler is needed.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Excel Aspen Plus Toolbar
• Connect Cell Combo Box
– Use this Combo Box to attach the current cell on the Excel spreadsheet to
a Defined Variable. If the Defined Variable chosen is already connected
to another cell, the link between that cell and the Defined Variable is
broken.
• Define Button
– Click the Define Button to create a new Defined Variable or to edit an
existing one. If this cell is already connected to a Defined Variable,
clicking on this button will allow you to edit it. If this cell is not connected
to a Defined Variable, clicking on this button will create a new Defined
Variable.
• Unlink Button
– Click the Unlink Button to remove the link between a cell and a Defined
Variable. Clicking on this button does not delete the Defined Variable.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Excel Aspen Plus Toolbar (Continued)
• Delete Button
– Click the Delete Button to remove the link between a cell and a
Defined variable and delete the Defined Variable.
• Refresh Button
– Click the Refresh Button to refresh the list of Defined Variables in the
Connect Cell Combo Box. You should click this button if you have
changed the list of Defined Variables by making changes on the
Calculator Define sheet.
• Changed Button
– Click the Changed Button to set the "Input Changed" flag of this
Calculator block. This will cause the Calculator to be re-executed the
next time you run the simulation. You should click this button if, after
the calculator block is executed, you make changes to the Excel
spreadsheet without making any changes on the Calculator block
forms.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Windows Interoperability
Objective:
Introduce the use of windows interoperability to transfer
data easily to and from other Windows programs.
Aspen Plus References
User Guide, Chapter 37, Working with Other Windows Programs
User Guide, Chapter 38, Using the Aspen Plus ActiveX Automation Server
©2000 AspenTech. All Rights Reserved.
Windows Interoperability
• Copying and pasting simulation data into spreadsheets
or reports
• Copying and pasting flowsheet graphics and plots into
reports
• Creating active links between Aspen Plus and other
Windows applications
• OLE - Object Linking and Embedding
• ActiveX automation
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Windows Interoperability - Examples
• Copy simulation results such as column profiles and stream results
into
– Spreadsheet for further analysis
– Word processor for reports and documentation
– Design program
– Database for case storage and management
• Copy flowsheet graphics and plots into
– Word processor for reports
– Slide making program for presentations
• Copy tabular data from spreadsheets into Aspen Plus for Data
Regression, Data-Fit, etc.
• Copy plots or tables into the Process Flowsheet Window.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Benefits of Windows Interoperability
• Benefits of Copy/Paste/Paste Link
– Live data links can be established that update these
applications as the process model is changed to automatically
propagate results of engineering changes.
– The benefits to the engineer are quick and error-free data
transfer and consistent engineering results throughout the
engineering work process.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Copy and Paste
1. Select
– Select the data fields or the graphical objects.
•
Multiple fields of data or objects can be selected by holding down
the CTRL key while clicking the mouse on the fields.
• Columns of data can be selected by clicking the column heading, or
an entire grid can be selected by clicking on the top left cell.
2. Copy
– Choose Copy from the Edit menu or type CTRL-C.
3. Paste
– Click the mouse in the input field where you want the
information and choose Paste from the Edit menu or click
CTRL-V.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
OLE - Object Linking and Embedding
• What is OLE?
– Applications can be used within applications.
• Uses of OLE
– Aspen Plus as the OLE server: Aspen Plus flowsheet graphics
can be embedded into a report document, or stream data into a
CAD drawing. The simulation model is actually contained in
the document, and could be delivered directly with that
document.
– Aspen Plus as the OLE container: Other windows applications
can be embedded within the Aspen Plus simulation.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
OLE (Continued)
• Examples of OLE
– OLE server: If the recipient of an engineering report, for
example, wanted to review the model assumptions, he could
access and run the embedded Aspen Plus model directly from
the report document.
– OLE container: For example, Excel spreadsheets and plots
could be used to enhance Aspen Plus flowsheet graphics.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Embedding Objects in the Flowsheet
• You can embed other applications as objects into the
Process Flowsheet window.
• You can do this in two ways:
– Using Copy and Paste
– Using the Insert dialog box
• You can edit the object embedded in the flowsheet by
double clicking on the object to edit it inside Aspen Plus.
• You can also move, resize or attach the object to a block
or stream in the flowsheet.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Copy and Paste Workshop 1
Objectives:
Use copy and paste to copy and paste the stage temperatures into a
spreadsheet.
Use the Cyclohexane flowsheet workshop (saved as CYCLOHEX.BKP)
Copy the temperature profile from COLUMN into a spreadsheet.
Generate a plot of the temperature using the plot wizard and copy and paste
the plot into the spreadsheet.
Save the spreadsheet as CYCLOHEX-result.xls
©2000 AspenTech. All Rights Reserved.
Copy and Paste Workshop 2
• Objective: Use copy and paste to copy the stream
results to a stream input form.
• Use the Cyclohexane flowsheet workshop (saved as
CYCLOHEX.BKP)
• Copy the stream results from stream RXIN into the input
form.
– Copy the compositions, the temperature and the pressure
separately.
Note: Reinitialize before running the simulation in order to
see how many iterations are needed before and
after the estimate is added.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Creating Active Links
• When copying and pasting information, you can create
active links between input or results fields in Aspen Plus
and other applications such as Word and Excel.
• The links update these applications as the process
model is modified to automatically propagate results of
engineering changes.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Creating Active Links
1. Open both applications.
2. Select the data (or object) that you want to paste and
link.
3. Choose Copy from the Edit menu.
4. In the location where you want to paste the link, choose
Paste Special from the Edit menu.
5. In the Paste Special dialog box, click the Paste Link
radio button.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Paste Link Demonstration
• Objective: Create an active link from Aspen Plus Results into a
spreadsheet.
• Start with the cumene flowsheet demonstration.
• Open a spreadsheet and create a cell with the temperature for the
cooler in it.
• Copy and paste the link into the Aspen Plus flowsheet.
• Copy and paste a link with the flow and composition of cumene in
the product stream into the spreadsheet.
• Change the temperature in the spreadsheet and then rerun the
flowsheet. Notice the changes.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Paste Link Workshop
• Objective: Create an active link from Aspen Plus results into a
spreadsheet
• Use the Cyclohexane flowsheet workshop (saved as
CYCLOHEX.BKP)
• Copy the Condenser and Reboiler duty results from the RadFrac
COLUMN Summary sheet. Use Copy with Format and copy the
value, the label and the units.
• Paste the results into the CYCLOHEX-results.xls spreadsheet as a
link. Use Paste Special and choose Link.
• Change the Reflux ratio in the column to 2 and rerun the flowsheet.
Check the spreadsheet to see that the results have changed there
also. Notice that the temperature profile results have not changed
since they were not pasted as a link.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Saving Files with Active Links
• Be sure to save both the link source file and the link
container file.
• If you save the link source with a different name, you
must save the link container after saving the link source.
• If you have active links in both directions between the
two applications and you change the name of both files,
you must do three Save operations:
– Save the first application with a new name.
– Save the second application with a new name.
– Save the first application again.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Running Files with Active Links
• When you open the link source file, there is nothing
special that you need to do.
• When you open the link container file, you will usually
see a dialog box asking you if you want to re-establish
the links. You can select Yes or No.
• To make a link source application visible:
– Select Links, from the Edit menu in Aspen Plus.
– In the Links dialog box, select the source file and click Open
Source.
Note: The Process Flowsheet must be the active window.
Links is not an option on the Edit menu if the Data
Browser is active.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heat Exchangers
Objective:
Introduce the unit operation models used for heat
exchangers and heaters.
Aspen Plus References:
Unit Operation Models Reference Manual, Chapter 3, Heat Exchangers
©2000 AspenTech. All Rights Reserved.
Heat Exchanger Blocks
• Heater - Heater or cooler
• HeatX - Two stream heat exchanger
• MHeatX - Multi-stream heat exchanger
• Hetran - Interface to B-JAC Hetran block
• Aerotran - Interface to B-JAC Aerotran block
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the Heater Model
• The Heater block mixes multiple inlet streams to produce
a single outlet stream at a specified thermodynamic
state.
• Heater can be used to represent:
– Heaters
– Coolers
– Valves
– Pumps (when work-related results are not needed)
– Compressors (when work-related results are not needed)
• Heater can also be used to set the thermodynamic
conditions of a stream.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heater Input Specifications
• Allowed combinations:
– Pressure (or Pressure drop) and one of:
•
•
•
•
•
Outlet temperature
Heat duty or inlet heat stream
Vapor fraction
Temperature change
Degrees of subcooling or superheating
– Outlet Temperature or Temperature change and one of:
•
Pressure
• Heat Duty
• Vapor fraction
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heater Input Specifications (Continued)
• For single phase use Pressure (drop) and one of:
– Outlet temperature
– Heat duty or inlet heat stream
– Temperature change
• Vapor fraction of 1 means dew point condition,
0 means bubble point
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heat Streams
• Any number of inlet heat streams can be specified for a
Heater.
• One outlet heat stream can be specified for the net heat
load from a Heater.
• The net heat load is the sum of the inlet heat streams
minus the actual (calculated) heat duty.
• If you give only one specification (temperature or
pressure), Heater uses the sum of the inlet heat streams
as a duty specification.
• If you give two specifications, Heater uses the heat
streams only to calculate the net heat duty.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the HeatX Model
• HeatX can perform simplified or rigorous rating
calculations.
• Simplified rating calculations (heat and material balance
calculations) can be performed if exchanger geometry is
unknown or unimportant.
• For rigorous heat transfer and pressure drop
calculations, the heat exchanger geometry must be
specified.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the HeatX Model (Continued)
• HeatX can model shell-and-tube exchanger types:
– Counter-current and co-current
– Segmental baffle TEMA E, F, G, H, J and X shells
– Rod baffle TEMA E and F shells
– Bare and low-finned tubes
• HeatX performs:
– Full zone analysis
– Heat transfer and pressure drop calculations
– Sensible heat, nucleate boiling, condensation
film coefficient calculations
– Built-in or user specified correlations
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the HeatX Model (Continued)
• HeatX cannot:
– Perform design calculations
– Perform mechanical vibration analysis
– Estimate fouling factors
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
HeatX Input Specifications
• Select one of the following specifications:
– Heat transfer area or Geometry
– Exchanger duty
– For hot or cold outlet stream:
•
•
•
•
•
Temperature
Temperature change
Temperature approach
Degrees of superheating / subcooling
Vapor fraction
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the MHeatX Model
• MHeatX can be used to represent heat transfer between
multiple hot and cold streams.
• Detailed, rigorous internal zone analysis can be
performed to determine pinch points.
• MHeatX uses multiple Heater blocks and heat streams to
enhance flowsheet convergence.
• Two-stream heat exchangers can also be modeled using
MHeatX.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
HeatX versus Heater
• Consider the following:
– Use HeatX when both sides are important.
– Use Heater when one side (e.g. the utility) is not important.
– Use two Heaters (coupled by heat stream, Calculator block or
design spec) or an MHeatX to avoid flowsheet complexity
created by HeatX.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Two Heaters versus One HeatX
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with Hetran and Aerotran
• The Hetran block is the interface to the B-JAC Hetran
program for designing and simulating shell and tube heat
exchangers.
• The Aerotran block is the interface to the B-JAC Aerotran
program for designing and simulating air-cooled heat
exchangers.
• Information related to the heat exchanger configuration
and geometry is entered through the Hetran or Aerotran
standalone program interface.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with HTRI-IST
• The HTRIIST block called HTRI IST as a subroutine for
licensed IST users only.
• Aspen Plus properties are used.
• Users can create a new IST model or access an existing
model.
• Key IST results are retrieved and reported inside Aspen
Plus.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heat Curves
• All of the heat exchanger models are able to calculate
Heat Curves (Hcurves).
• Tables can be generated for various independent
variables (typically duty or temperature) for any property
that Aspen Plus can generate.
• These tables can be printed, plotted, or exported for use
with other heat exchanger design software.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heat Curves Tabular Results
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Heat Curve Plot
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
HeatX Workshop
• Objective: Compare the simulation of a heat exchanger that uses
water to cool a hydrocarbon mixture using three methods: a shortcut
HeatX, a rigorous HeatX and two Heaters connected with a Heat
stream.
• Hydrocarbon stream
– Temperature: 200 C
– Pressure: 4 bar
– Flowrate: 10000 kg/hr
– Composition: 50 wt% benzene, 20% styrene,
20% ethylbenzene and 10% water
• Cooling water
– Temperature: 20 C
– Pressure: 10 bar
– Flow rate: 60000 kg/hr
– Composition: 100% water
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
HeatX Workshop (Continued)
When finished, save as filename: HEATX.BKP
HEATER-1
HCLD-IN
HCLD-OUT
SHOT-OUT
RHOT-OUT
SHEATX
SCLD-IN
SCLD-OUT
RHEATX
RCLD-IN
RCLD-OUT
Q-TRANS
HEATER-2
HHOT-IN
HHOT-OUT
SHOT-IN
RHOT-IN
Start with the General with Metric Units Template.
Use the NRTL-RK Property Method for the hydrocarbon streams.
Specify that the valid phases for the hydrocarbon stream is Vapor-Liquid-Liquid.
Specify that the Steam Tables are used to calculate the properties for the cooling water
streams on the Block BlockOptions Properties sheet.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
HeatX Workshop (Continued)
• Shortcut HeatX simulation:
– Hydrocarbon stream exit has a vapor fraction of 0
– No pressure drop in either stream
• Two Heaters simulation:
– Use the same specifications as the shortcut HeatX simulation
• Rigorous HeatX simulation:
– Hydrocarbons in shell leave with a vapor fraction of 0
– Shell diameter 1 m, 1 tube pass
– 300 bare tubes, 3 m length, pitch 31 mm, 21 mm ID, 25 mm OD
– All nozzles 100 mm
– 5 baffles, 15% cut
– Create heat curves containing all info required for thermal design.
– Change the heat exchanger specification to Geometry and re-run.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Pressure Changers
Objective:
Introduce the unit operation models used to change pressure:
pumps, compressors, and models for calculating pressure
change through pipes and valves.
Aspen Plus References:
Unit Operation Models Reference Manual, Chapter 6, Pressure Changers
©2000 AspenTech. All Rights Reserved.
Pressure Changer Blocks
• Pump - Pump or hydraulic turbine
• Compr - Compressor or turbine
• MCompr - Multi-stage compressor or turbine
• Valve - Control valve
• Pipe - Single-segment pipe
• Pipeline - Multi-segment pipe
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the Pump Model
• The Pump block can be used to simulate:
– Pumps
– Hydraulic turbines
• Power requirement is calculated or input.
• A Heater model can be used for pressure change
calculations only.
• Pump is designed to handle a single liquid phase.
• Vapor-liquid or vapor-liquid-liquid calculations can be
specified to check outlet stream phases.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Pump Performance Curves
• Rating can be done by specifying scalar parameters or a
pump performance curve.
• Specify:
– Dimensional curves
•
Head versus flow
• Power versus flow
– Dimensionless curves:
•
Head coefficient versus flow coefficient
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the Compr Model
• The Compr block can be used to simulate:
– Polytropic centrifugal compressor
– Polytropic positive displacement compressor
– Isentropic compressor
– Isentropic turbine
• MCompr is used for multi-stage compressors.
• Power requirement is calculated or input.
• A Heater model can be used for pressure change calculations only.
• Compr is designed to handle both single and multiple phase
calculations.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the MCompr Model
• The MCompr block can be used to simulate:
– Multi-stage polytropic centrifugal compressor
– Multi-stage polytropic positive displacement compressor
– Multi-stage isentropic compressor
– Multi-stage isentropic turbine
• MCompr can have an intercooler between each stage,
and an aftercooler after the last stage.
– You can perform one-, two-, or three- phase flash calculations
in the intercoolers.
– Each cooler can have a liquid knockout stream, except the
cooler after the last stage.
– Intercooler specifications apply to all subsequent coolers.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Compressor Performance Curves
• Rating can be done by specifying a compressor
performance curve.
• Specify:
– Dimensional curves
•
Head versus flow
• Power versus flow
– Dimensionless curves:
•
Head coefficient versus flow coefficient
• Compr cannot handle performance curves for a turbine.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Work Streams
• Any number of inlet work streams can be specified for
pumps and compressors.
• One outlet work stream can be specified for the net work
load from pumps or compressors.
• The net work load is the sum of the inlet work streams
minus the actual (calculated) work.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the Valve Model
• The Valve block can be used to simulate:
– Control valves
– Pressure drop
• The pressure drop across a valve is related to the valve
flow coefficient.
• Flow is assumed to be adiabatic.
• Valve can perform single or multiple phase calculations.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the Valve Model (Continued)
• The effect of head loss from pipe fittings can be included.
• There are three types of calculations:
– Adiabatic flash for specified outlet pressure (pressure changer)
– Calculate valve flow coefficient for specified outlet pressure
(design)
– Calculate outlet pressure for specified valve (rating)
• Valve can check for choked flow.
• Cavitation index can be calculated.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Working with the Pipe Model
• The Pipe block calculates the pressure drop and heat transfer in a
single pipe segment.
• The Pipeline block can be used for a multiple-segment pipe.
• Pipe can perform single or multiple phase calculations.
• If the inlet pressure is known, Pipe calculates the outlet pressure.
• If the outlet pressure is known, Pipe calculates the inlet pressure
and updates the state variables of the inlet stream.
• Entrance effects are not modeled.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Pressure Changers Block Example
• Add a Compressor and a Valve to the cumene flowsheet.
COMPR
RECYCLE
VALVE
RECYCLE2
RECYCLE3
Outlet Pressure = 3 psig
Polytropic compressor model
using GPSA method
Discharge pressure = 5 psig
FEED
REAC-OUT
REACTOR
COOL-OUT
SEP
COOL
PRODUCT
Filename: CUMENE-P.BKP
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Pressure Changers Workshop
• Objective: Add pressure changer unit operations to
the Cyclohexane flowsheet.
• Start with the Cyclohexane Workshop flowsheet
(CYCLOHEX.BKP)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Pressure Changers Workshop (Continued)
Isentropic
4 bar pressure change
COMP
H2IN
PURGE
VFLOW
VAP
H2RCY2
FEED-MIX
PURGE2
20 bar outlet pressure
Globe valve
V810 equal percent flow
1.5-in size
REACT
RXIN
FEEDPUMP
BZIN
H2RCY
VALVE
HP-SEP
RXOUT
BZIN2
CHRCY3
Pump efficiency = 0.6
Driver efficiency = 0.9
LTENDS
LIQ
PIPE
PUMP
CHRCY2
Performance Curve
Head
Flow
[m]
[cum/hr]
40
20
250
10
300
5
400
3
©2000 AspenTech. All Rights Reserved.
Carbon Steel
Schedule 40
1-in diameter
25-m length
CHRCY
COLFD
LFLOW
26 bar outlet pressure
PRODUCT
COLUMN
When finished, save as
filename: PRESCHNG.BKP
Introduction to Aspen Plus
Flowsheet Convergence
Objective:
Introduce the idea of convergence blocks, tear
streams and flowsheet sequences
Aspen Plus References
User Guide, Chapter 17, Convergence
©2000 AspenTech. All Rights Reserved.
Convergence Blocks
• Every design specification and tear stream has an associated
convergence block.
• Convergence blocks determine how guesses for a tear stream or
design specification manipulated variable are updated from iteration
to iteration.
• Aspen Plus-defined convergence block names begin with the
character “$.”
– User defined convergence block names must not begin with the
character “$.”
• To determine the convergence blocks defined by Aspen Plus, look
under the “Flowsheet Analysis” section in the Control Panel
messages.
• User convergence blocks can be specified under
/Data/Convergence/Convergence...
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Convergence Block Types
• Different types of convergence blocks are used for different purposes:
– To converge tear streams:
•
•
•
•
WEGSTEIN
DIRECT
BROYDEN
NEWTON
– To converge design specifications:
•
•
•
SECANT
BROYDEN
NEWTON
– To converge design specifications and tear streams:
•
•
BROYDEN
NEWTON
– For optimization:
•
•
SQP
COMPLEX
• Global convergence options can be specified on the Convergence
ConvOptions Defaults form.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Flowsheet Sequence
• To determine the flowsheet sequence calculated by
Aspen Plus, look under the “COMPUTATION ORDER
FOR THE FLOWSHEET” section in the Control Panel, or
on the left-hand pane of the Control Panel window.
• User-determined sequences can be specified on the
Convergence Sequence form.
• User-specified sequences can be either full or partial.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Tear Streams
• Which are the recycle streams?
• Which are the possible tear streams?
S7
S1
B1
MIXER
S2
B2
MIXER
S3
B3
FSPLIT
S4
B4
S5
FSPLIT
S6
• A tear stream is one for which Aspen Plus makes an
initial guess, and iteratively updates the guess until two
consecutive guesses are within a specified tolerance.
• Tear streams are related to, but not the same as recycle
streams.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Tear Streams (Continued)
• To determine the tear streams chosen by Aspen Plus,
look under the “Flowsheet Analysis” section in the
Control Panel.
• User-determined tear streams can be specified on the
Convergence Tear form.
• Providing estimates for tear streams can facilitate or
speed up flowsheet convergence (highly recommended,
otherwise the default is zero).
• If you enter information for a stream that is in a “loop,”
Aspen Plus will automatically try to choose that stream to
be a tear stream.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Reconciling Streams
• Simulation results for a stream can be copied onto the its
input form.
• Select a stream on the flowsheet, click the right mouse
button and select “Reconcile” from the list to copy stream
results to the input form.
– Two state variables must be selected for the stream flash
calculation.
– Component flows, or component fractions and total flow can be
copied.
– Mole, mass, or standard liquid volume basis can be selected.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Convergence Workshop
• Objective
– Converge this flowsheet.
– Start with the file CONVERGE.BKP.
100 lbmol/hr
T=70 F
P=35 psia
50 lbmol/hr Ethylene Glycol
T=165 F
P=15 psia
FEED
XH20
= 0.4
XMethanol = 0.3
XEthanol = 0.3
COLUMN
GLYCOL
DIST
PREHEATR
BOT-COOL
VAPOR
Area = 65 sqft
PREFLASH
FEED-HT
Theoretical Stages = 10
Reflux Ratio = 5
Distillate to Feed Ratio = 0.2
Column Pressure = 1 atm
Feed Stage = 5
Total Condenser
DP=0
Q=0
LIQ
BOT
Use NRTL-RK Property Method
©2000 AspenTech. All Rights Reserved.
When finished, save as
filename: CONV-R.BKP
Introduction to Aspen Plus
Convergence Workshop (Continued)
• Hints for Convergence Workshop
– Questions to ask yourself:
•
•
•
•
•
What messages are displayed in the control panel?
Why do some of the blocks show zero flow?
What is the Aspen Plus-generated execution sequence for the
flowsheet?
Which stream does Aspen Plus choose as a tear stream?
What are other possible tear streams?
– Recommendation
•
Give initial estimates for a tear stream.
• Of the three possible tear streams you could choose, which do you
know the most about? (Note: If you enter information for a stream that
is in a “loop,” Aspen Plus will automatically choose that stream to be a
tear stream and set up a convergence block for it.)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Convergence Workshop (Continued)
• Questions to ask yourself:
– Does the flowsheet converge after entering initial estimates for the tear
stream?
– If not, why not? (see control panel)
– How is the err/tol value behaving, and what is its value at the end of the run?
– Does it appear that increasing the number of convergence iterations will help?
– What else can be tried to improve this convergence?
• Recommendation
– Try a different convergence algorithm (e.g. Direct, Broyden, or Newton).
Note: You can either manually create a convergence block to converge the
tear stream of your choice, or you can change the default convergence
method for all tear streams on the Convergence
Conv Options Defaults Default Methods sheet.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Full-Scale Plant Modeling Workshop
• Objective: Practice and apply many of the
techniques used in this course and learn how to best
approach modeling projects
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Full-Scale Plant Modeling Workshop
• Objective: Model a methanol plant.
• The process being modeled is a methanol plant. The
basic feed streams to the plant are Natural Gas, Carbon
Dioxide (assumed to be taken from a nearby Ammonia
Plant) and Water. The aim is to achieve the methanol
production rate of approximately 62,000 kg/hr, at a purity
of at least 99.95 % wt.
• This is a large flowsheet that would take an experienced
engineer more than an afternoon to complete. Start
building the flowsheet and think about how you would
work to complete the project.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
General Guidelines
• Build the flowsheet one section at a time.
• Simplify whenever possible. Complexity can always be
added later.
• Investigate the physical properties.
– Use Analysis.
– Check if binary parameters are available.
– Check for two liquid phases.
– Use an appropriate equation of state for the portions of the
flowsheet involving gases and use an activity coefficient model
for the sections where non-ideal liquids may be present.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Full-Scale Plant Modeling Workshop
Air
FURNACE
Fuel
MEOHRXR
SYNCOMP
SPLIT1
COOL4
E121
SPLIT2
FL3
COOL2 COOL3
MKUPST
M2 FEEDHTR
FL2
MIX2
COOL1
CIRC
E122
FL4
BOILER FL1
H2OCIRC
REFORMER
CO2 CO2COMP M1
E223
E124
SATURATE
NATGAS
TOPPING
CH4COMP
FL5
M4
REFINING
MKWATER
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Part 1: Front-End Section
MKUPST
M2
From Furnace
FEEDHTR
To BOILER
REFORMER
H2OCIRC
CO2COMP
CO2
NATGAS
©2000 AspenTech. All Rights Reserved.
M1
SATURATE
CH4COMP
Introduction to Aspen Plus
Part 1: Front-End Section (Continued)
• Carbon Dioxide Stream – CO2
– Temperature
• Circulation Water - H2OCIRC
– Pure water stream
= 43 C
– Pressure = 1.4 bar
– Flow = 410000 kg/hr
– Flow = 24823 kg/hr
– Temperature
– Mole Fraction
– Pressure = 26 bar
•
•
•
•
•
CO2
H2 H2O
CH4
N2 -
0.0094
0.0028
= 195 C
0.9253
0.0606
0.0019
• Makeup Steam - MKUPST
– Stream of pure steam
• Natural Gas Stream - NATGAS
– Flow = 40000 kg/hr
– Temperature = 26 C
– Pressure = 26 bar
– Pressure = 21.7 bar
– Vapor Fraction = 1
– Flow = 29952 kg/hr
– Adjust the makeup steam flow to
– Mole Fraction
•
•
•
•
•
CO2
CH4
N2
C2H6
C3H8
©2000 AspenTech. All Rights Reserved.
-
0.0059
0.9539
0.0008
0.0391
0.0003
achieve a desired steam to methane
molar ratio of 2.8 in the Reformer feed
REFFEED.
Introduction to Aspen Plus
Part 1: Front-End Section (Continued)
• Carbon Dioxide Compressor - CO2COMP
–
Discharge Pressure = 27.5 bar
– Compressor Type = 2 stage
• Natural Gas Compressor - CH4COMP
–
Discharge Pressure = 27.5 bar
– Compressor Type = single stage
• Reformer Process Side Feed Stream Pre-Heater - FEEDHTR
–
Exit Temperature = 560 C
– Pressure drop = 0
• Saturation Column - SATURATE
–
1.5 inch metal pall ring packing.
– Estimated HETP = 10 x 1.5 inches = 381 mm
–
Height of Packing = 15 meters
– No condenser and no reboiler.
• Reformer Reactor - REFORMER
–
Consists of two parts: the Furnace portion and the Steam Reforming portion
– Exit Temperature of the Steam Reforming portion = 860 C
–
Pressure = 18 bar
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Part 1: Front-End Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Mass Flow kg/hr
Volume Flow cum/hr
Enthalpy MMkcal/hr
Mole Flow kmol/hr
CO
CO2
H2
WATER
METHANOL
METHANE
NITROGEN
BUTANOL
DME (DIMETHYLETHER)
ACETONE
OXYGEN
ETHANE
PROPANE
©2000 AspenTech. All Rights Reserved.
Reformer Product
860
18
1
10266.6541
139696.964
53937.9538
-213.933793
1381.68394
751.335833
4882.77068
2989.25863
0.000686384
258.513276
3.08402321
0
2.06E-10
2.18E-08
1.80E-15
0.007007476
6.74097E-07
Introduction to Aspen Plus
Part 2: Heat Recovery Section
SYNCOMP
To Methanol Loop
COOL4
FL3
COOL2
COOL3
FL2
COOL1
From Reformer
BOILER
FL1
To REFINING
©2000 AspenTech. All Rights Reserved.
To TOPPING
Introduction to Aspen Plus
Part 2: Heat Recovery Section (Continued)
• This section consists of a series of heat exchangers and flash vessels used to recover the
available energy and water in the Reformed Gas stream.
BOILER
Exit temperature = 166 C
Exit Pressure = 18 bar
COOL1
Exit temperature = 136 C
Exit Pressure = 18 bar
FL1
Pressure Drop = 0 bar
Heat Duty = 0 MMkcal/hr
FL2
Exit Pressure = 17.7 bar
Heat Duty = 0 MMkcal/hr
COOL2
Exit temperature = 104 C
Exit Pressure = 17.9 bar
COOL3
Exit temperature = 85 C
Pressure Drop = 0.1 bar
COOL4
Exit temperature = 40 C
Exit Pressure = 17.6 bar
©2000 AspenTech. All Rights Reserved.
FL3
Exit Pressure = 17.4 bar
Heat Duty = 0 MMkcal/hr
SYNCOM
Two Stage Polytropic compressor
Discharge Pressure = 82.5 bar
Intercooler Exit Temperature = 40 C
Introduction to Aspen Plus
Part 2: Heat Recovery Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
©2000 AspenTech. All Rights Reserved.
To Methanol Loop
40.0
82.50
0.997465769
7302.28917
Introduction to Aspen Plus
Part 3: Methanol Synthesis Section
MEOHRXR
To Furnace
SPLIT1
From SYNCOMP
E121
SPLIT2
MIX2
CIRC
E122
FL4
E223
E124
To FL5
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Part 3: Methanol Synthesis Section (Continued)
•
Methanol Reactor - MEOHRXR
–
–
–
–
Tube cooled reactor
Exit Temperature from the tubes = 240 C
No pressure drop across the reactor
Reactions
•
•
•
•
•
•
E121
–
–
•
•
–
E124
–
–
Exit Temperature - 45 C
Exit Pressure - 75.6 bar
©2000 AspenTech. All Rights Reserved.
–
Exit Pressure = 75.6 bar
–
Heat Duty = 0 MMkcal/hr
CIRC
– Single stage compressor
– Discharge Pressure = 83 bar
– Discharge Temperature = 55 C
•
SPLIT1
– Split Fraction = 0.8 to stream to E121
•
SPLIT2
– Stream PURGE = 9000 kg/hr
– Stream RECYCLE = 326800 kg/hr
Cold Side Exit Temperature - 120 C
Exit Temperature - 60 C
Exit Pressure - 77.3 bar
FL4
•
E223
–
•
(Equilibrium)
(+15 C Temperature Approach)
(Molar extent 0.2kmol/hr)
(Molar extent 0.8kmol/hr)
(Molar extent 0.3kmol/hr)
Exit Temperature - 150 C
Exit Pressure - 81 bar
E122
–
•
CO + H2O <-> CO2 + H2
CO2 + 3H2 <-> CH3OH + H2O
2CH3OH <-> DIMETHYLETHER + H2O
4CO + 8H2 <-> N-BUTANOL + 3H2O
3CO + 5H2 <-> ACETONE + 2H2O
Introduction to Aspen Plus
Part 3: Methanol Synthesis Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
©2000 AspenTech. All Rights Reserved.
To FL5
45.0
75.60
0.000
2673.354
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Mass Flow kg/hr
Volume Flow cum/hr
Enthalpy MMkcal/hr
Mole Flow kmol/hr
CO
CO2
H2
WATER
METHANOL
METHANE
NITROGEN
BUTANOL
DME
ACETONE
OXYGEN
ETHANE
PROPANE
MEOHRXR Product
249.7
83.00
1.000
29091.739
413083.791
15637.807
-559.129
799.563
3137.144
13379.353
644.301
2140.046
8896.430
91.428
0.845
1.864
0.588
0.000
0.177
0.000
Introduction to Aspen Plus
Part 4: Distillation Section
To Furnace
From FL4
From COOL1
FL5
From COOL2
TOPPING
REFINING
M4
MKWATER
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Part 4: Distillation Section (Continued)
•
Makeup Steam - MKWATER
–
–
–
–
–
•
Stream of pure water
Flow = 10000 kg/hr
Pressure = 5 bar
Temperature = 40 C
Adjust the make-up water flow (stream MKWATER) to the CRUDE stream to achieve a stream composition of
23 wt.% of water in the stream feeding the Topping column (stream TOPFEED) to achieve 100 ppm methanol
in the Refining column BTMS stream.
Topping Column - TOPPING
–
Number of Stages = 51 (including condenser and reboiler)
–
Condenser Type = Partial Vapor/Liquid
Feed stage = 14
Distillate has both liquid and vapor streams
Distillate rate = 1400 kg/hr
Pressure profile: stage 1 = 1.5 bar and stage 51 = 1.8 bar
Distillate vapor fraction = 99 mol%
Stage 2 heat duty = -7 Mmkcal/hr
–
–
–
–
–
–
–
–
–
–
–
Stage 51 heat duty Specified by the heat stream
Reboiler heat duty is provided via a heat stream from block COOL2
Boil-up Ratio is approximately 0.52
Valve trays
The column has two condensers. To represent the liquid flow connections a pumparound can be used between
stage 1 and 3.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Part 4: Distillation Section (Continued)
• Refining Column - REFINING
–
Number of Stages = 95 (including condenser and reboiler)
–
Condenser Type = Total
–
Distillate Rate = 1 kg/hr
– Feed stage = 60
Liquid Product sidedraw from Stage 4 @ 62000 kg/hr (Stream name – PRODUCT)
– Liquid Product sidedraw from Stage 83 @ 550 kg/hr (Stream name – FUSELOIL)
–
–
Reflux rate = 188765 kg/hr
– Pressure profile: stage 1= 1.5bar and stage 95=2bar
–
Reboiler heat duty is provided via a conventional reboiler supplemented by a heat stream from a
heater block to stage 95
–
Boil-up Ratio is approximately 4.8
– Valve trays
–
To meet environmental regulations, the bottoms stream must contain no more than 100ppm by weight
of methanol as this stream is to be dumped to a nearby river.
• FL5
–
Exit Pressure
5 bar
–
Heat Duty
0 MMkcal/hr
• M4
–
For water addition to the crude methanol
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Part 4: Distillation Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Mass Flow kg/hr
Volume Flow cum/hr
Enthalpy MMkcal/hr
Mole Flow kmol/hr
CO
CO2
H2
WATER
METHANOL
METHANE
NITROGEN
BUTANOL
DME
ACETONE
OXYGEN
ETHANE
PROPANE
©2000 AspenTech. All Rights Reserved.
TOPFEED
LTENDS
SECPURGE REFINE
PRODUCT BTMS
LIQPURGE FUSELOIL
43.8
33.1
33.1
85.8
75.1
120.1
74.8
90.4
5.00
1.50
1.50
1.80
1.52
2.00
1.50
1.95
0.001
1.000
0.000
0.000
0.000
0.000
0.000
0.000
3029.767
33.807
0.341
2995.618
1928.736
1047.117
0.031
19.733
82623.475
1388.896
11.104
81223.475
61800.974
18871.500
1.000
550.000
111.175
573.782
0.014
107.201
83.975
21.058
0.001
0.722
-186.388
-2.802
-0.020
-178.587
-107.391
-69.633
-0.002
-1.199
0.004
26.537
0.014
1054.851
1945.891
1.267
0.003
0.798
0.116
0.285
0.000
0.000
0.000
0.004
26.535
0.014
0.000
5.591
1.267
0.003
0.000
0.116
0.276
0.000
0.000
0.000
0.000
0.002
0.000
0.000
0.334
0.000
0.000
0.000
0.000
0.005
0.000
0.000
0.000
0.000
0.000
0.000
1054.851
1939.966
0.000
0.000
0.798
0.000
0.004
0.000
0.000
0.000
0.000
0.000
0.000
0.000
1928.733
0.000
0.000
0.000
0.000
0.004
0.000
0.000
0.000
0.000
0.000
0.000
1046.942
0.059
0.000
0.000
0.117
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.031
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
7.910
11.143
0.000
0.000
0.681
0.000
0.000
0.000
0.000
0.000
Introduction to Aspen Plus
Part 5: Furnace Section
To REFORMER
From FL5
Air
From SPLIT2
FURNACE
Fuel
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Part 5: Furnace Section (Continued)
• Air to Furnace - AIR
– Temperature = 366 C
– Pressure = 1 atm
– Flow = 281946 kg/hr
– Adjust the air flow to achieve 2%(vol.) of oxygen in the
FLUEGAS stream.
• Fuel to Furnace - FUEL
– Flow = 9436 kg/hr
– Conditions and composition are the same as for the natural gas
stream
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Maintaining Aspen Plus Simulations
Objective:
Introduce how to store simulations and retrieve
them from your computer environment
Aspen Plus References:
User Guide, Chapter 15, Managing Your Files
©2000 AspenTech. All Rights Reserved.
File Formats in Aspen Plus
File Type Extension
Format Description
Document
*.apw
Binary
File containing simulation input and results and
intermediate convergence information
Backup
*.bkp
ASCII
Archive file containing simulation input and
results
Template
*.apt
ASCII
Template containing default inputs
Input
*.inp
Text
Simulation input
Run Message *.cpm
Text
Calculation history shown in the Control Panel
History
*.his
Text
Detailed calculation history and diagnostic
messages
Summary
*.sum
ASCII
Simulation results
Problem
Definition
*.appdf
Binary
File containing arrays and intermediate
convergence information used in the simulation
calculations
Report
*.rep
Text
Simulation report
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
File Type Characteristics
• Binary files
– Operating system and version specific
– Not readable, not printable
• ASCII files
– Transferable between operating systems
– Upwardly compatible
– Contain no control characters, “readable”
– Not intended to be printed
• Text files
– Transferable between operating systems
– Upwardly compatible
– Readable, can be edited
– Intended to be printed
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
How to Store a Simulation
Three ways to store simulations:
Document
Backup
Input
(*.apw)
(*.bkp)
(*.inp)
Simulation definition
Yes
Yes
Yes
Convergence info
Yes
No
No
Results
Yes
Yes
No
Flowsheet Graphics
Yes
Yes
Yes/No
User readable
No
No
Yes
Open/save speed
High
Low
Lowest
Space requirements
High
Low
Lowest
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Template Files
• Template files are used to set your personal preferences:
– Units of measurement
– Property sets for stream reports
– Composition basis
– Stream report format
– Global flow basis for input specifications
– Setting Free-Water option
– Selection for Stream-Class
– Property Method
– (Required) Component list
– Other application-specific defaults
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
How to Create a Personal Template
• Any flowsheet (complete or incomplete) can be saved as
a template file.
• In order to have a personal template appear on the
Personal sheet of the New dialog box, put the template
file into the Aspen Plus GUI\Templates\Personal folder.
• The text on the Setup Specifications Description sheet
will appear in the Preview window when the template file
is selected in the New dialog box.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Maintaining Your Computer
• Aspen Plus 10 runs best on a healthy computer.
• Minimum RAM
GUI only
Win 95 and 32 MB
Win 98
Windows NT 64 MB
GUI and
Engine
64 MB
96 MB
• Having more is better -- if near minimum, avoid running
too many other programs along with Aspen Plus.
• Active links increase needed RAM.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Maintaining Your Hard Disk
• Keep plenty of free space on disk used for:
– Your Aspen working directory
– Windows swap files
• Delete unneeded files:
– Old .appdf, .his, etc.
– Aspen document files (*.apw) that aren’t active
– Aspen temporary files (_4404ydj.appdf, for example)
• Defragment regularly (once a week), even if Windows
says you don’t need to -- make the free space
contiguous.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Customizing the Look of Your
Flowsheet
Objective:
Introduce several ways of annotating your flowsheet
to create informative Process Flow Diagrams
Aspen Plus References:
User Guide, Chapter 14, Annotating Process Flowsheets
Related Topics:
User Guide, Chapter 37, Working with Other Windows Programs
©2000 AspenTech. All Rights Reserved.
Customizing the Process Flow Diagram
• Add annotations
• Display global data
– Text
– Stream flowrate, pressure and
– Graphics
temperature
– Heat stream duty
– Tables
• Add OLE objects
– Add a titlebox
– Add plots or diagrams
– Work stream power
– Block duty and power
• Use PFD mode
– Change flowsheet connectivity
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Viewing
• Use the View menu to select the elements that you wish
to view:
– PFD Mode
– Global Data
– Annotation
– OLE Objects
• All of the elements can be turned on and off
independently.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Adding Annotation
• Use the Draw Toolbar to add text and graphics. (Select
Toolbar… from the View menu to select the Draw Toolbar
if it is not visible.)
• To create a stream table, click on the Stream Table
button on the Results Summary Streams Material sheet.
• Annotation objects can be attached to flowsheet
elements such as streams or blocks.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Example of a Stream Table
Heat and Material Balance Table
Stream ID
COOL-OUT
FEED
PRODUCT
REAC-OUT
RECYCLE
Temperature
F
130.0
220.0
130.1
854.7
130.1
Pressure
PSI
14.60
36.00
14.70
14.70
14.70
0.054
1.000
0.000
1.000
1.000
44.342
80.000
41.983
44.342
2.359
Vapor Frac
Mole Flow
LBMOL/HR
Mass Flow
LB/HR
4914.202
4807.771
4807.772
4914.202
106.431
Volume Flow
CUFT/HR
1110.521
15648.095
93.470
42338.408
1003.782
Enthalpy
MMBTU/HR
-0.490
1.980
-0.513
2.003
0.023
Mole Flow
LBMOL/HR
BENZENE
2.033
40.000
1.983
2.033
0.050
PROPYLEN
4.224
40.000
1.983
4.224
2.241
38.017
38.085
0.069
CUMENE
38.085
Mole Frac
©2000 AspenTech. All Rights Reserved.
BENZENE
0.046
0.500
0.047
0.046
0.021
PROPYLEN
0.095
0.500
0.047
0.095
0.950
CUMENE
0.859
0.906
0.859
0.029
Introduction to Aspen Plus
Adding Global Data
• On the Results View sheet when selecting Options from the Tools
menu, choose the block and stream results that you want displayed
as Global Data.
• Check Global Data on the View menu to display the data on the
flowsheet.
130
15
Temperature (F)
106
Pressure (psi)
Flow Rate (lb/hr)
Q
RECYCLE
Duty (Btu/hr)
220
36
4808
REACTOR
855
130
15
15
4914
4914
COOL
FEED
REAC-OUT
Q=0
COOL-OUT
130
SEP
15
4808
Q=-2492499
Q=0
PRODUCT
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Using PFD Mode
• In this mode, you can add or delete unit operation icons
to the flowsheet for graphical purposes only.
• Using PFD mode means that you can change flowsheet
connectivity to match that of your plant.
• PFD-style drawing is completely separate from the
graphical simulation flowsheet. You must return to
simulation mode if you want to make a change to the
actual simulation flowsheet.
• PFD Mode is indicated by the Aqua border around the
flowsheet.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Examples of When to Use PFD Mode
• In the simulation flowsheet, it may be necessary to use
more than one unit operation block to model a single
piece of equipment in a plant.
– For example, a reactor with a liquid product and a vent may
need to be modeled using an RStoic reactor and a Flash2
block. In the report, only one unit operation icon is needed to
represent the unit in the plant.
• On the other hand, some pieces of equipment may not
need to be explicitly modeled in the simulation flowsheet.
– For example, pumps are frequently not modeled in the
simulation flowsheet; the pressure change can be neglected or
included in another unit operation block.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Annotation Workshop
• Objective: Use annotation to create a process flow diagram for
the cyclohexane flowsheet
• Part A
– Using the cyclohexane production Workshop (saved as
CYCLOHEX.BKP), display all stream and block global data.
• Part B
– Add a title to the flowsheet diagram.
• Part C
– Add a stream table to the flowsheet diagram.
• Part D
– Using PFD Mode, add a pump for the BZIN stream for graphical
purposes only.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Estimation of Physical Properties
Objective:
Provide an overview of estimating physical
property parameters in Aspen Plus
Aspen Plus References:
User Guide, Chapter 30, Estimating Property Parameters
Physical Property Methods and Models Reference Manual,
Chapter 8, Property Parameter Estimation
©2000 AspenTech. All Rights Reserved.
What is Property Estimation?
• Property Estimation is a system to estimate parameters
required by physical property models. It can be used to
estimate:
– Pure component physical property constants
– Parameters for temperature-dependent models
– Binary interaction parameters for Wilson, NRTL and UNIQUAC
– Group parameters for UNIFAC
• Estimations are based on group-contribution methods
and corresponding-states correlations.
• Experimental data can be incorporated into estimation.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Using Property Estimation
• Property Estimation can be used in two ways:
– On a stand-alone basis: Property Estimation Run Type
– Within another Run Type: Flowsheet, Property Analysis, Data
Regression, PROPERTIES PLUS or Assay Data Analysis
• You can use Property Estimation to estimate properties
for both databank and non-databank components.
• Property Estimation information is accessed in the
Properties Estimation folder.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Estimation Methods and Requirements
• User Guide, Chapter 30, Estimating Property
Parameters, has a complete list of properties that can be
estimated, as well as the available estimation methods
and their respective requirements.
• This same information is also available under the on-line
help in the estimation forms.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps For Using Property Estimation
1. Define molecular structure on the Properties Molecular
Structure form.
2. Enter any experimental data using Parameters or Data
forms.
– Experimental data such as normal boiling point (TB) is very
important for many estimation methods. It should be
entered whenever possible.
3. Activate Property Estimation and choose property
estimation options on the Properties Estimation Input
form.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Defining Molecular Structure
• Molecular structure is required for all group-contribution
methods used in Property Estimation. You can:
– Define molecular structure in the general format and allow
Aspen Plus to determine functional groups,
or
– Define molecular structure in terms of functional groups for
particular methods
• Reference: For a list of available group-contribution
method functional groups, see Aspen Plus Physical
Property Data Reference Manual, Chapter 3, Group
Contribution Method Functional Groups.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps For Defining General Structure
1. Sketch the structure of the molecule on paper.
2. Assign a number to each atom, omitting hydrogen. (The numbers
must be consecutive starting with 1.)
3. Go to the Properties Molecular Structure Object Manager, choose
the component, and select Edit.
4. On the Molecular Structure General sheet, define the molecule by
its connectivity. Describe two atoms at a time:
– Specify the types of atoms (C, O, S, …)
– Specify the type of bond that connects the two atoms (single,
double, …)
Note: If the molecule is a non-databank component, on the
Components Specifications form, enter a Component ID, but
do not enter a Component name or Formula.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Example of Defining Molecular Structure
• Example of defining molecular structure for isobutyl
alcohol using the general method
– Sketch the structure of the molecule, and assign a number to
each atom, omitting hydrogen.
C1
C2
C4
O5
C3
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Example of Defining Molecular Structure
• Go to the Properties Molecular Structure Object Manager, choose
the component, and select Edit.
• On Properties Molecular Structure General sheet, describe molecule
by its connectivity, two atoms at a time.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Atom Types
Current available atom types:
Atom Type
Description
Atom Type
Description
C
Carbon
P
Phosphorous
O
Oxygen
Zn
Zinc
N
Nitrogen
Ga
Gallium
S
Sulfur
Ge
Germanium
B
Boron
As
Arsenic
Si
Silicon
Cd
Cadmium
F
Fluorine
Sn
Tin
CL
Chlorine
Sb
Antimony
Br
Bromine
Hg
Mercury
I
Iodine
Pb
Lead
Al
Aluminum
Bi
Bismuth
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Bond Types
• Current available bond types:
– Single bond
– Double bond
– Triple bond
– Benzene ring
– Saturated 5-membered ring
– Saturated 6-membered ring
– Saturated 7-membered ring
– Saturated hydrocarbon chain
Note: You must assign consecutive atom numbers to Benzene ring,
Saturated 5-membered ring, Saturated 6-membered ring,
Saturated 7-membered ring, and Saturated hydrocarbon chain
bonds.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps For Using Property Estimation
 1.
Define molecular structure on the Properties Molecular
Structure form.
2. Enter any experimental data using Parameters or Data
forms.
– Experimental data such as normal boiling point (TB) is very
important for many estimation methods. It should be
entered whenever possible.
3. Activate Property Estimation and choose property
estimation options on the Properties Estimation Input
form.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Example of Entering Additional Data
• Enter following data for isobutyl alcohol into the
simulation to improve the estimated values.
– Normal boiling point (TB) = 107.6 C
– Critical temperature (TC) = 274.6 C
– Critical pressure (PC) = 43 bar
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Example of Entering Additional Data
• Go to the Properties Parameters Pure Component Object Manager
and create a new Scalar parameter form.
• Enter the parameters, the components, and the values.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps For Using Property Estimation
1.
2.
Define molecular structure on the Properties Molecular
Structure form.
Enter any experimental data using Parameters or Data
forms.
– Experimental data such as normal boiling point (TB) is very
important for many estimation methods. It should be
entered whenever possible.
3. Activate Property Estimation and choose property
estimation options on the Properties Estimation
Input form.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Activating Property Estimation
• To turn on Property Estimation, go to the Properties
Estimation Input Setup sheet, and select one of the
following:
– Estimate all missing parameters
•
Estimates all missing required parameters and any parameters you
may request in the optional Pure Component, T-Dependent, Binary, and
UNIFAC-Group sheets
– Estimate only the selected parameters
•
Estimates on the parameter types you select on this sheet (and then
specify on the appropriate additional sheets)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Property Estimation Notes
• You can save your property data specifications,
structures, and estimates as backup files, and import
them into other simulations (Flowsheet, Data
Regression, Property Analysis, or Assay Data Analysis
Run-Types.)
• You can change the Run type on the Setup
Specifications Global sheet to continue the simulation in
the same file.
• If you want to change the Run type back to Property
Estimation from another Run type, no flowsheet
information is lost even though it may not be visible in
the Property Estimation mode.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Property Estimation Workshop
• Objective: Estimate the properties of a dimer,
ethycellosolve.
• Ethylcellosolve is not in any of the Aspen Plus
databanks.
• Use a Run Type of Property Estimation, and estimate the
properties for the new component.
• The formula for the component is shown below, along
with the normal boiling point obtained from literature.
Formula: CH3 - CH2 - O - CH2 - CH2 - O - CH2 - CH2 - OH TB = 195 C
When finished, save as
filename: PCES.BKP
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Property Estimation Workshop (Continued)
1. Use a Run Type of Property Estimation and enter the
structure and data for the Dimer.
2. Run the estimation, and examine the results.
– Note that the results of the estimation are automatically
written to parameters forms, for use in other simulations.
3. Change the Run Type back to Flowsheet.
4. Go to the Properties Estimation Input Setup sheet, and
choose Do not estimate any parameters.
5. Optionally, add a flowsheet and use this component.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Electrolytes
Objective:
Introduce the electrolyte capabilities in Aspen Plus
Aspen Plus References:
User Guide, Chapter 6, Specifying Components
Physical Property Methods and Models Reference Manual, Chapter 5, Electrolyte Simulation
©2000 AspenTech. All Rights Reserved.
Electrolytes Examples
• Solutions with acids, bases or salts
• Sour water solutions
• Aqueous amines or hot carbonate for gas sweetening
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Characteristics of an Electrolyte System
• Some molecular species dissociate partially or
completely into ions in a liquid solvent
• Liquid phase reactions are always at chemical
equilibrium
• Presence of ions in the liquid phase requires non-ideal
solution thermodynamics
• Possible salt precipitation
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Types of Components
• Solvents - Standard molecular species
– Water
– Methanol
– Acetic Acid
• Soluble Gases - Henry’s Law components
– Nitrogen
– Oxygen
– Carbon Dioxide
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Types of Components (Continued)
• Ions - Species with a charge
– H3O+
– OH– Na+
– Cl– Fe(CN)63-
• Salts - Each precipitated salt is a new pure component.
– NaCl(s)
– CaCO3(s)
– CaSO4•2H2O (gypsum)
– Na2CO3•NaHCO3 •2H2O (trona)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Apparent and True Components
• True component approach
– Result reported in terms of the ions, salts and molecular
species present after considering solution chemistry
• Apparent component approach
– Results reported in terms of base components present before
considering solution chemistry
– Ions and precipitated salts cannot be apparent components
– Specifications must be made in terms of apparent components
and not in terms of ions or solid salts
• Results are equivalent.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Apparent and True Components Example
• NaCl in water
– Solution chemistry
•
NaCl
-->
• Na+ + Cl- <-->
Na+ + ClNaCl(s)
– Apparent components
•
H2O, NaCl
– True components:
•
H2O, Na+, Cl-, NaCl(s)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Electrolyte Wizard
• Generates new components (ions and solid salts)
• Revises the Pure component databank search order so that the first
databank searched is now ASPENPCD.
• Generates reactions among components
• Sets the Property method to ELECNRTL
• Creates a Henry’s Component list
• Retrieves parameters for
– Reaction equilibrium constant values
– Salt solubility parameters
– ELECNRTL interaction parameters
– Henry’s constant correlation parameters
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Electrolyte Wizard (Continued)
• Generated chemistry can be modified. Simplifying the
Chemistry can make the simulation more robust and
decrease execution time.
Note: It is the user’s responsibility to ensure that the
Chemistry is representative of the actual chemical
system.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Simplifying the Chemistry
• Typical modifications include:
– Adding to the list of Henry’s components
– Eliminating irrelevant salt precipitation reactions
– Eliminating irrelevant species
– Adding species and/or reactions that are not in the electrolytes
expert system database
– Eliminating irrelevant equilibrium reactions
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Limitations of Electrolytes
• Restrictions using the True component approach:
– Liquid-liquid equilibrium cannot be calculated.
– The following models may not be used:
•
Equilibrium reactors:
• Kinetic reactors:
• Shortcut distillation:
• Rigorous distillation:
©2000 AspenTech. All Rights Reserved.
RGibbs and REquil
RPlug, RCSTR, and RBatch
Distl, DSTWU and SCFrac
MultiFrac and PetroFrac
Introduction to Aspen Plus
Limitations of Electrolytes (Continued)
• Restrictions using the Apparent component approach:
– Chemistry may not contain any volatile species on the right
side of the reactions.
– Chemistry for liquid-liquid equilibrium may not contain
dissociation reactions.
– Input specification cannot be in terms of ions or solid salts.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Electrolyte Demonstration
• Objective: Create a flowsheet using electrolytes.
• Create a simple flowsheet to mix and flash two feed streams
containing aqueous electrolytes. Use the Electrolyte Wizard to
generate the Chemistry.
Temp = 25 C
Pres = 1 bar
10 kmol/hr H2O
Filename: ELEC1.BKP
1 kmol/hr HCl
HCL
VAPOR
MIX
NAOH
Temp = 25 C
Pres = 1 bar
10 kmol/hr H2O
1.1 kmol/hr NaOH
©2000 AspenTech. All Rights Reserved.
MIXED
MIXER
FLASH
FLASH2
Isobaric
Molar vapor fraction = 0.75
P-drop = 0
Adiabatic
LIQUID
Introduction to Aspen Plus
Steps for Using Electrolytes
1. Specify the possible apparent components on the
Components Specifications Selection sheet.
2. Click on the Elec Wizard button to generate
components and reactions for electrolyte systems.
There are 4 steps:
Step 1: Define base components and select reaction
generation options.
Step 2: Remove any undesired species or reactions from the
generated list.
Step 3: Select simulation approach for electrolyte
calculations.
Step 4: Review physical properties specifications and modify
the generated Henry components list and reactions.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Electrolytes (Continued)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Electrolytes (Continued)
Step 1: Define base components and select reaction
generation options.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Electrolytes (Continued)
Step 2: Remove any undesired species or reactions from
the generated list.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Electrolytes (Continued)
Step 3: Select simulation approach for electrolyte
calculations.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Electrolytes (Continued)
Step 4: Review physical properties specifications and modify the
generated Henry components list and reactions.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Electrolyte Workshop
• Objective: Create a flowsheet using electrolytes.
• Create a simple flowsheet to model the treatment of a sulfuric acid
waste water stream using lime (Calcium Hydroxide). Use the
Electrolyte Wizard to generate the Chemistry. Use the true
component approach.
Temperature = 25C
Pressure = 1 bar
Flowrate = 10 kmol/hr
5 mole% sulfuric acid solution
Note: Remove from the chemistry:
CaSO4(s)
CaSO4•1:2W:A(s)
WASTEWAT
B1
LIME
Temperature = 25C
Temperature = 25C
P-drop = 0
Pressure = 1 bar
Flowrate = 10 kmol/hr
5 mole% lime (calcium hydroxide) solution
©2000 AspenTech. All Rights Reserved.
LIQUID
When finished, save as
filename: ELEC.BKP
Introduction to Aspen Plus
Electrolyte Workshop (Continued)
1. Open a new Electrolytes with Metric units flowsheet.
2. Draw the flowsheet.
3. Enter the necessary components and generate the
electrolytes using the Electrolytes Wizard. Select the
true approach and remove the solid salts not needed
from the generated reactions.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Sour Water Stripper Workshop
• Objective: Model a sour water stripper using electrolytes.
• Create a simple flowsheet to model a sour water stripper. Use the
Electrolyte Wizard to generate the Chemistry. Use the apparent component
approach.
VAPOR
Saturated vapor
Above stage 3
P = 15 psia
10,000 lbs/hr
SOURWAT
Mass fractions:
H2O
0.997
NH3
0.001
H2S
0.001
CO2
0.001
B1
Theoretical trays: 9
(does not include condenser)
Partial condenser
Reflux Ratio (Molar): 25
No reboiler
STEAM
On stage 10
P = 15 psia
Vapor frac = 1
2,000 lbs/hr
©2000 AspenTech. All Rights Reserved.
BOTTOMS
Introduction to Aspen Plus
Sour Water Stripper Workshop (Continued)
1. Open a new Electrolytes with English units flowsheet.
2. Draw the flowsheet.
3. Enter the necessary components and generate the
electrolytes using the Electrolytes Wizard. Select the
apparent approach and remove all solid salts used in
the generated reactions.
Questions: Why aren’t the ionic species’ compositions
displayed on the results forms? How can they be
added?
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Sour Water Stripper Workshop (Continued)
3. Add a sensitivity analysis
a) Vary the steam flow rate from 1000-3000 lb/hr and tabulate
the ammonia concentration in the bottoms stream. The
target is 50 ppm.
b) Vary the column reflux ratio from 10-50 and observe the
condenser temperature. The target is 190 F.
4. Create design specifications
a) After hiding the sensitivity blocks, solve the column with two
design specifications. Use the targets and variables from
part 3.
Save as: SOURWAT.BKP
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Handling
Objective:
Provide an overview of the solid handling
capabilities
Aspen Plus References:
User Guide, Chapter 6, Specifying Components
Physical Property Methods and Models Reference Manual, Chapter 3, Property Model Descriptions
©2000 AspenTech. All Rights Reserved.
Classes of Components
• Conventional Components
– Vapor and liquid components
– Solid salts in solution chemistry
• Conventional Inert Solids (CI Solids)
– Solids that are inert to phase equilibrium and salt
precipitation/solubility
• Nonconventional Solids (NC Solids)
– Heterogeneous substances inert to phase, salt, and chemical
equilibrium that cannot be represented with a molecular
structure
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Specifying Component Type
• When specifying components on the Components
Specifications Selection sheet, choose the appropriate
component type in the Type column.
–
Conventional - Conventional Components
– Solid - Conventional Inert Solids
–
Nonconventional - Nonconventional Solids
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Conventional Components
• Components participate in vapor and liquid equilibrium
along with salt and chemical equilibrium.
• Components have a molecular weight.
– e.g. water, nitrogen, oxygen, sodium chloride, sodium ions,
chloride ions
– Located in the MIXED substream
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Conventional Inert Solids (CI Solids)
• Components are inert to phase equilibrium and salt
precipitation/solubility.
• Chemical equilibrium and reaction with conventional
components is possible.
• Components have a molecular weight.
– e.g. carbon, sulfur
– Located in the CISOLID substream
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Nonconventional Solids (NC Solids)
• Components are inert to phase, salt or chemical
equilibrium.
• Chemical reaction with conventional and CI Solid
components is possible.
• Components are heterogeneous substances and do not
have a molecular weight.
– e.g. coal, char, ash, wood pulp
– Located in the NC Solid substream
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Component Attributes
• Component attributes typically represent the composition
of a component in terms of some set of identifiable
constituents
• Component attributes can be
– Assigned by the user
– Initialized in streams
– Modified in unit operation models
• Component attributes are carried in the material stream.
• Properties of nonconventional components are
calculated by the physical property system using
component attributes.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Component Attribute Descriptions
Attribute Type
Elements
Description
PROXANAL
1. Moisture
2. Fixed Carbon
3. Volatile Matter
4. Ash
Proximate analysis, weight %dry
basis
ULTANAL
1. Ash
2. Carbon
3. Hydrogen
4. Nitrogen
5. Chlorine
6. Sulfur
7. Oxygen
Ultimate analysis, weight % dry
basis
SULFANAL
1. Pyritic
2. Sulfate
3. Organic
Forms of sulfur analysis, weight %
of original coal, dry basis
GENANAL
1. Constituent 1
2. Constituent 2
:
20. Constituent 20
General constituent analysis, weight
or volume %
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solid Properties
• For conventional components and conventional solids
– Enthalpy, entropy, free energy and molar volume are
computed.
– Property models in the Property Method specified on the
Properties Specification Global sheet are used.
• For nonconventional solids
– Enthalpy and mass density are computed.
– Property models are specified on the Properties Advanced NC-
Props form.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Properties - Conventional Solids
For Enthalpy, Free Energy, Entropy and Heat Capacity
• Barin Equations
– Single parameter set for all properties
– Multiple parameter sets may be available for selected
temperature ranges
– List INORGANIC databank before SOLIDS
• Conventional Equations
– Combines heat of formation and free energies of formation with
heat capacity models
– Aspen Plus and DIPPR model parameters
– List SOLIDS databank before INORGANIC
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Properties - Conventional Solids
• Solid Heat Capacity
– Heat capacity polynomial model
C
C C
CpoS  C1  C2T  C3T 2  4  52  63
T T
T
– Used to calculate enthalpy, entropy and free energy
– Parameter name: CPSP01
• Solid Molar Volume
– Volume polynomial model
V S  C1  C2T  C3T 2  C4T 3  C5T 4
– Used to calculate density
– Parameter name: VSPOLY
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Properties - Nonconventional Solids
• Enthalpy
– General heat capacity polynomial model: ENTHGEN
– Uses a mass fraction weighted average
– Based on the GENANAL attribute
– Parameter name: HCGEN
• Density
– General density polynomial model: DNSTYGEN
– Uses a mass fraction weighted average
– Based on the GENANAL attribute
– Parameter name: DENGEN
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Properties - Special Models for Coal
• Enthalpy
– Coal enthalpy model: HCOALGEN
– Based on the ULTANAL, PROXANAL and SULFANAL
attributes
• Density
– Coal density model: DCOALIGT
– Based on the ULTANAL and SULFANAL attributes
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Built-in Material Stream Classes
Stream Class
Description
CONVEN*
Conventional components only
MIXNC
Conventional and nonconventional solids
MIXCISLD
Conventional components and inert solids
MIXNCPSD
Conventional components and nonconventional
solids with particle size distribution
MIXCIPSD
Conventional components and inert solids with
particle size distribution
MIXCINC
Conventional components and inert solids and
nonconventional solids
MIXCINCPSD
Conventional components and nonconventional
solids with particle size distribution
* system default
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Unit Operation Models
• General Principles
– Material streams of any class are accepted.
– The same stream class should be used for inlet and outlet
streams (exceptions: Mixer and ClChng).
– Attributes (components or substream) not recognized are
passed unaltered through the block.
– Some models allow specifications for each substream present
(examples: Sep, RStoic).
– In vapor-liquid separation, solids leave with the liquid.
– Unless otherwise specified, outlet solid substreams are in
thermal equilibrium with the MIXED substream.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Workshop 1
• Objective: Model a conventional solids dryer.
• Dry SiO2 from a water content of 0.5% to 0.1% using air.
• Notes
– Change the Stream class type to: MIXCISLD.
– Put the SiO2 in the CISOLID substream.
– The pressure and temperature has to be the same in all the
sub-streams of a stream.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Workshop 1 (Continued)
Temp = 190 F
Pres = 14.7 psia
Flow = 1 lbmol/hr
0.79 mole% N2
0.21 mole% O2
AIR-OUT
Design specification:
Vary the air flow rate
from 1 to 10 lbmol/hr to
achieve 99.9 wt.% SiO2
[SiO2/(SiO2+Mixed)]
AIR
DRYER
WET
Temp = 70 F
Pres = 14.7 psia
FLASH2
DRY
Pressure Drop = 0
Adiabatic
995 lb/hr SiO2
5 lb/hr H2O
Use the SOLIDS Property Method
©2000 AspenTech. All Rights Reserved.
When finished, save as
filename: SOLIDWK1.BKP
Introduction to Aspen Plus
Solids Workshop 2
• Objective: Use the solids unit operations to model the
particulate removal from a feed of gasifier off gases.
• The processing of gases containing small quantities of particulate
materials is rendered difficult by the tendency of the particulates to
interfere with most operations (e.g., surface erosion, fouling,
plugging of orifices and packing). It is therefore necessary to
remove most of the particulate materials from the gaseous stream.
Various options are available for this purpose (Cyclone, Bag-filter,
Venturi-scrubber, and an Electrostatic precipitator) and their
particulate separation efficiency can be changed by varying their
design and operating conditions. The final choice of equipment is a
balance between the technical performance and the cost associated
with using a particular unit.
• In this workshop, various options for removing particulates from the
syngas obtained by coal gasification are compared.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Solids Workshop 2 (Continued)
Temp = 650 C
Pres = 1 bar
Gas Flowrate = 1000 kmol/hr
Ash Flowrate = 200 kg/hr
Composition (mole-frac)
CO
0.19
CO2
0.20
H2
0.05
H2S
0.02
O2
0.03
CH4
0.01
H2O
0.05
N2
0.35
SO2
0.10
G-CYC
F-CYC
Temp = 40 C
S-CYC
Pres = 1 bar
Water Flowrate = 700 kg/hr
G-SCRUB
FEED
F-SCRUB
DUPL
Particle size distribution (PSD)
Size limit
wt. %
[mu]
0- 44
30
44- 63
10
63-90
20
90-130
15
130-200
10
S-SCRUB
V-SCRUB
G-ESP
Design Mode
Separation Efficiency = 0.9
Dielectric constant = 1.5
F-BF
ESP
S-ESP
G-BF
15
When finished, save as
©2000 AspenTech. All Rights Reserved.
Design Mode
Separation Efficiency = 0.9
LIQ
F-ESP
200-280
Design Mode
High Efficiency
Separation Efficiency = 0.9
CYC
filename: SOLIDWK2.BKP
Design Mode
Max. Pres. Drop = 0.048 bar
FABFILT
S-BF
Introduction to Aspen Plus
Solids Workshop 2 (Continued)
• Coal ash is mainly clay and heavy metal oxides and can be
considered a non-conventional component.
• HCOALGEN and DCOALIGT can be used to calculate the enthalpy
and material density of ash using the ultimate, proximate, and sulfur
analyses (ULTANAL, PROXANAL, SULFANAL). These are specified
on the Properties Advanced NC-Props form.
• Component attributes (ULTANAL, PROXANAL, SULFANAL) are
specified on the Stream Input form. For ash, zero all non-ash
attributes.
• The PSD limits can be changed on the Setup Substreams PSD
form.
• Use the IDEAL Property Method.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Optimization
Objective:
Introduce the optimization capability in Aspen Plus
Aspen Plus References:
User Guide, Chapter 22, Optimization
Related Topics:
User Guide, Chapter 17, Convergence
User Guide, Chapter 18, Accessing Flowsheet Variables
©2000 AspenTech. All Rights Reserved.
Optimization
• Used to maximize/minimize an objective function
• Objective function is expressed in terms of flowsheet
variables and In-Line Fortran.
• Optimization can have zero or more constraints.
• Constraints can be equalities or inequalities.
• Optimization is located under /Data/Model Analysis
Tools/Optimization
• Constraint specification is under /Data/Model Analysis
Tools/Constraint
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Optimization Example
REACTOR
A, B
FEED
Desired Product C
By-product D
Waste Product E
$ 1.30 / lb
$ 0.11 / lb
$ - 0.20 /lb
A + B --> C + D + E
A, B, C, D, E
PRODUCT
• For an existing reactor, find the reactor temperature and
inlet amount of reactant A that maximizes the profit from
this reactor. The reactor can only handle a maximum
cooling load of Q.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Optimization Example (Continued)
• What are the measured (sampled) variables?
– Outlet flowrates of components C, D, E
• What is the objective function to be maximized?
– Maximize 1.30*(lb/hr C) + 0.11*(lb/hr D) - 0.20*(lb/hr E)
• What is the constraint?
– The calculated duty of the reactor can not exceed Q.
• What are the manipulated (varied) variables?
– Reactor temperature
– Inlet amount of reactant A
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Optimization
1. Identify measured (sampled) variables.
– These are the flowsheet variables used to calculate the
objective function (Optimization Define sheet).
2. Specify objective function (expression).
– This is the Fortran expression that will be maximized or
minimized (Optimization Objective & Constraints sheet).
3. Specify maximization or minimization of objective
function (Optimization Objective & Constraints sheet).
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Steps for Using Optimization (Continued)
4. Specify constraints (optional).
– These are the constraints used during the optimization
(Optimization Objective & Constraints sheet).
5. Specify manipulated (varied) variables.
– These are the variables that the optimization block will
change to maximize/minimize the objective function
(Optimization Vary sheet).
6. Specify bounds for manipulated (varied) variables.
– These are the lower and upper bounds within which to vary
the manipulated variable (Optimization Vary sheet).
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Notes
1. The convergence of the optimization can be sensitive to
the initial values of the manipulated variables.
2. It is best if the objective, the constraints, and the
manipulated variables are in the range of 1 to 100.
This can be accomplished by simply multiplying or
dividing the function.
3. The optimization algorithm only finds local maxima and
minima in the objective function. It is theoretically
possible to obtain a different maximum/minimum in the
objective function, in some cases, by starting at a
different point in the solution space.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Notes (Continued)
4. Equality constraints within an optimization are similar to
design specifications.
5. If an optimization does not converge, run sensitivity
studies with the same manipulated variables as the
optimization, to ensure that the objective function is not
discontinuous with respect to any of the manipulated
variables.
6. Optimization blocks also have convergence blocks
associated with them. Any general techniques used
with convergence blocks can be used if the optimization
does not converge.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Optimization Workshop
• Objective: Optimize steam usage for a process.
• The flowsheet shown below is part of a Dichloro-Methane solvent
recovery system. The two flashes, TOWER1 and TOWER2, are run
adiabatically at 19.7 and 18.7 psia respectively. The stream FEED
contains 1400 lb/hr of Dichloro-Methane and 98600 lb/hr of water at
100oF and 24 psia. Set up the simulation as shown below, and
minimize the total usage of steam in streams STEAM1 and
STEAM2, both of which contain saturated steam at 200 psia. The
maximum allowable concentration of Dichloro-Methane in the
stream EFFLUENT from TOWER2 is 150 ppm (mass) to within a
tolerance of a tenth of a ppm. Use the NRTL Property Method. Use
bounds of 1000 lb/hr to 20,000 lb/hr for the flowrate of the two steam
streams. Make sure stream flows are reported in mass flow and
mass fraction units before running. Refer to the Notes slides for
some hints on the previous page if there are problems converging
the optimization.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Optimization Workshop (Continued)
TOP1
STEAM1
TOWER1
FEED
TOP2
BOT1
TOWER2
STEAM2
EFFLUENT
When finished, save as
filename: OPT.BKP
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence
Objective:
Introduce the convergence algorithms and
initialization strategies available in RadFrac
Aspen Plus References:
Unit Operation Models Reference Manual, Chapter 4, Columns
©2000 AspenTech. All Rights Reserved.
RadFrac Convergence Methods
• RadFrac provides a variety of convergence methods for
solving separation problems. Each convergence method
represents a convergence algorithm and an initialization
method. The following convergence methods are
available:
– Standard (default)
– Petroleum / Wide-Boiling
– Strongly non-ideal liquid
– Azeotropic
– Cryogenic
– Custom
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Convergence Methods (Continued)
Method
Algorithm
Initialization
Standard
Standard
Standard
Petroleum / Wide-boiling
Sum-Rates
Standard
Strongly non-ideal liquid
Nonideal
Standard
Azeotropic
Newton
Azeotropic
Cryogenic
Standard
Cryogenic
Custom
select any
select any
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence Algorithms
• RadFrac provides four convergence algorithms:
– Standard (with Absorber=Yes or No)
– Sum-Rates
– Nonideal
– Newton
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Standard Algorithm
• The Standard (default, Absorber=No) algorithm:
– Uses the original inside-out formulation
– Is effective and fast for most problems
– Solves design specifications in a middle loop
– May have difficulties with extremely wide-boiling or highly non-
ideal mixtures
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Standard Algorithm (Continued)
• The Standard algorithm with Absorber=Yes:
– Uses a modified formulation similar to the classical sum-rates
algorithm
– Applies to absorbers and strippers only
– Has fast convergence
– Solves design specifications in a middle loop
– May have difficulties with highly non-ideal mixtures
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Sum-Rates Algorithm
• The Sum-Rates algorithm:
– Uses a modified formulation similar to the classical sum-rates
algorithm
– Solves design specifications simultaneously with the column-
describing equations
– Is effective and fast for wide boiling mixtures and problems with
many design specifications
– May have difficulties with highly non-ideal mixtures
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Nonideal Algorithm
• The Nonideal algorithm:
– Includes a composition dependency in the local physical
property models
– Uses the continuation convergence method
– Solves design specifications in a middle loop
– Is effective for non-ideal problems
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Newton Algorithm
• The Newton algorithm:
– Is a classic implementation of the Newton method
– Solves all column-describing equations simultaneously
– Uses the dogleg strategy of Powell to stabilize convergence
– Can solve design specifications simultaneously or in an outer
loop
– Handles non-ideality well, with excellent convergence in the
vicinity of the solution
– Is recommended for azeotropic distillation columns
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Vapor-Liquid-Liquid Calculations
• You can use the Standard, Newton and Nonideal
algorithms for 3-phase Vapor-Liquid-Liquid systems. On
the RadFrac Setup Configuration sheet, select VaporLiquid-Liquid in the Valid Phases field.
• Vapor-Liquid-Liquid calculations:
– Handle column calculations involving two liquid phases
rigorously
– Handle decanters
– Solve design specifications using:
•
Either the simultaneous (default) loop or the middle loop approach for
the Newton algorithm
• The middle loop approach for all other algorithms
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Convergence Method Selection
• For Vapor-Liquid systems, start with the Standard
convergence method. If the Standard method fails:
– Use the Petroleum / Wide Boiling method if the mixture is very
wide-boiling.
– Use the Custom method and change Absorber to Yes on the
RadFrac Convergence Algorithm sheet, if the column is an
absorber or a stripper.
– Use the Strongly non-ideal liquid method if the mixture is highly
non-ideal.
– Use the Azeotropic method for azeotropic distillation problems
with multiple solutions possible. The Azeotropic algorithm is
also another alternative for highly non-ideal systems.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Convergence Method Selection (Continued)
• For Vapor-Liquid-Liquid systems:
– Start by selecting Vapor-Liquid-Liquid in the Valid Phases field
of the RadFrac Setup Configuration sheet and use the
Standard convergence method.
– If the Standard method fails, try the Custom method with the
Nonideal or the Newton algorithm.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Initialization Method
• Standard is the default Initialization method for RadFrac.
• This method:
– Performs flash calculations on composite feed to obtain
average vapor and liquid compositions
– Assumes a constant composition profile
– Estimates temperature profiles based on bubble and dew point
temperatures of composite feed
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Specialized Initialization Methods
• Four specialized Initialization methods are available.
Use:
Crude
Chemical
For:
Wide boiling systems with
multi-draw columns
Narrow boiling chemical systems
Azeotropic
Cryogenic
Azeotropic distillation columns
Cryogenic applications
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Estimates
• RadFrac does not usually require estimates for
temperature, flow and composition profiles.
• RadFrac may require:
– Temperature estimates as a first trial in case of convergence
problems
– Liquid and/or vapor flow estimates for the separation of wide
boiling mixtures.
– Composition estimates for highly non-ideal, extremely wide-
boiling (for example, hydrogen-rich), azeotropic distillation or
vapor-liquid-liquid systems.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Composition Estimates
• The following example illustrates the need for
composition estimates in an extremely wide-boiling point
system:
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence Workshop
• Objective: Apply the convergence hints explained in this
section.
• HCl column in a VCM production plant
• Feed
– 130000 kg/hr at 50C, 18 bar
– 19.5%wt HCl, 33.5%wt VCM, 47%wt EDC
– (VCM : vinyl-chloride, EDC : 1,2-dichloroethane)
• Column
– 33 theoretical stages
– partial condenser (vapor distillate)
– kettle reboiler
– pressure : top 17.88 bar, bottom 18.24 bar
– feed on stage 17
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence Workshop (Continued)
• First Step:
– Specify the column.
•
Set the distillate flow rate to be equal to the mass flow rate of HCl in the
feed.
• Specify that the mass reflux ratio is 0.7.
• Use Peng-Robinson equation of state (PENG-ROB).
– Question: How should these specifications be implemented?
• Note: Look at the results.
– Temperature profile
– Composition profile
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence Workshop (Continued)
• Second step:
– VCM in distillate and HCl in bottom are much too high!
– Allow only 5 ppm of HCl in the residue and 10 ppm VCM in the
distillate.
– Question: How should these specifications be implemented?
• Note: You may have some convergence difficulties.
– Apply the guidelines presented in this section
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
RadFrac Convergence Workshop (Continued)
Use the PENG-ROB Property method
flow : HCl in feed
130000 kg/h
50 C, 18 bar,
HCl
19.5%wt
VCM
33.5%wt
EDC
47.0%wt
max 10 ppm VCM
17.88 bar
mass reflux ratio:0.7
feed on stage 17
18.24 bar
max 5 ppm HCl
When finished, save as filename: VCMHCL1.BKP (step 1) and VCMHCL2.BKP (step 2)
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
Vinyl Chloride Monomer (VCM) Workshop
• Objective: Set up a flowsheet of a VCM process using the tools
learned in the course.
• Vinyl chloride monomer (VCM) is produced through a high pressure, noncatalytic process involving the pyrolysis of 1,2-dichloroethane (EDC)
according to the following reaction:
CH2Cl-CH2Cl
HCl + CHCl=CH2
• The cracking of EDC occurs at 500 C and 30 bar in a direct fired furnace.
1000 kmol/hr of pure EDC feed enters the reactor at 20 C and 30 bar. EDC
conversion in the reactor is maintained at 55%. The hot gases from the
reactor are subcooled by 10 degrees before fractionation.
• Two distillation columns are used for the purification of the VCM product. In
the first column, anhydrous HCl is removed overhead and sent to the oxy
chlorination unit. In the second column, VCM product is removed overhead
and the bottoms stream containing unreacted EDC is recycled back to the
furnace. Overheads from both columns are removed as saturated liquids.
The HCL column is run at 25 bar and the VCM column is run at 8 bar. Use
the RK-SOAVE Property Method.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus
VCM Workshop (Continued)
CH2Cl-CH2Cl
HCl + CHCl=CH2
EDC
1000 kmol/hr EDC
20C
30 bar
FEED
HCl
RStoic Model
VCM
RadFrac Model
Heater Model
REACTOUT
COOLOUT
RadFrac Model
HCLOUT
COL1
VCMOUT
CRACK
RECYCIN
Pump Model
500 C
30 bar
EDC Conv. = 55%
QUENCH
10 deg C subcooling
0.5 bar pressure drop
VCMIN
15 stages
Reflux ratio = 1.082
Distillate to feed ratio = 0.354
Feed enters above stage 8
Column pressure = 25 bar
PUMP
30 bar outlet pressure
COL2
10 stages
Reflux ratio = 0.969
Distillate to feed ratio = 0.550
Feed enters above stage 7
Column pressure = 8 bar
RECYCLE
Use RK-SOAVE property method
©2000 AspenTech. All Rights Reserved.
When finished, save as
filename: VCM.BKP
Introduction to Aspen Plus
VCM Workshop (Continued)
Part A:
• With the help of the process flow diagram on the previous page, set
up a flowsheet to simulate the VCM process. What are the values of
the following quantities?
1. Furnace heat duty ________
2. Quench cooling duty ________
3. Quench outlet temperature ________
4. Condenser and Reboiler duties for COL2
________________
5. Concentration of VCM in the product stream ________
Part B:
• The conversion of EDC to VCM in the furnace varies between 50%
and 55%. Use the sensitivity analysis capability to generate plots of
the furnace heat duty and quench cooling duty as a function of EDC
conversion.
©2000 AspenTech. All Rights Reserved.
Introduction to Aspen Plus