Introduction to Aspen Plus
Speaker: Bor-Yih Yu(余柏毅)
Date: 2013/09/02
f00524023@ntu.edu.tw
PSE Laboratory
Department of Chemical Engineering
Nation Taiwan University
(綜合 room 402)
Edited by: 程建凱/吳義章/余柏毅
Introduction to Aspen Plus
Part 1: Introduction
2
What is Aspen Plus
• Aspen Plus is a market-leading process modeling tool for
conceptual design, optimization, and performance monitoring
for the chemical, polymer, specialty chemical, metals and
minerals, and coal power industries.
Ref: http://www.aspentech.com/products/aspen-plus.cfm
3
What Aspen Plus provides
• Physical Property Models
– World’s largest database of pure component and phase equilibrium
data for conventional chemicals, electrolytes, solids, and polymers
– Regularly updated with data from U. S. National Institute of Standards
and Technology (NIST)
• Comprehensive Library of Unit Operation Models
– Addresses a wide range of solid, liquid, and gas processing equipment
– Extends steady-state simulation to dynamic simulation for safety and
controllability studies, sizing relief valves, and optimizing transition,
startup, and shutdown policies
– Enables you build your own libraries using Aspen Custom Modeler or
programming languages (User-defined models)
4
Ref: Aspen Plus® Product Brochure
More Detailed
• Properties analysis
– Properties of pure component and mixtures (Enthalpy,
density, viscosity, heat capacity,…etc)
– Phase equilibrium (VLE, VLLE, azeotrope calculation…etc)
– Parameters estimation for properties models (UNIFAC
method for binary parameters, Joback method for boiling
points…etc)
– Data regression from experimental deta
• Process simulation
– pump, compressor, valve, tank, heat exchanger, CSTR, PFR,
distillation column, extraction column, absorber, filter,
crystallizer…etc
5
What course Aspen Plus
can be employed for
•
•
•
•
•
•
•
MASS AND ENERGY BALANCES
PHYSICAL CHEMISTRY
CHEMICAL ENGINEERING THERMODYNAMICS
CHEMICAL REACTION ENGINEERING
UNIT OPERATIONS
PROCESS DESIGN
PROCESS CONTROL
6
Lesson Objectives
• Familiar with the interface of Aspen Plus
• Learn how to use properties analysis
• Learn how to setup a basic process simulation
7
Outline
•
•
•
•
•
•
•
Part 1 : Introduction
Part 2 : Startup
Part 3 : Properties analysis
Part 4 : Running Simulation in Aspen Plus (simple units)
Part 5 : Running Simulation in Aspen Plus (Reactors)
Part 6 : Running Simulation in Aspen Plus (Distillation)
Part 7 (additional): Running Simulation in Aspen Plus (Design,
spec and vary)
8
Introduction to Aspen Plus
Part 2: Startup
9
Start with Aspen Plus
Aspen Plus User Interface
Aspen Plus Startup
11
Interface of Aspen Plus
Help
Setup
Components
Properties
Streams
Blocks
Data Browser
Next
Check Result
Stop
Reinitialize
Step
Start
Control Panel
ProcessFlowsheet
Flowsheet Windows
Process
Windows
ModelLibrary
Library (View|
Model
(View| Model
ModelLibrary
Library) )
Stream
Status message
12
More Information
Help for Commands for Controlling Simulations
13
Data Browser
• The Data Browser is a sheet and form viewer with a
hierarchical tree view of the available simulation
input, results, and objects that have been defined
14
Setup – Specification
Run Type
Input mode
15
Input components
Remark: If available, are
16
Properties
Process type(narrow the number of
methods available)
Base method: IDEAL, NRTL, UNIQAC, UNIFAC…
17
Property Method Selection—General Rule
Example 1:
water - benzene
Example 2:
benzene - toluene
18
Typical Activity Coefficient Models
Non-Randon-Two Liquid Model (NRTL)
Uniquac Model
Unifac Model
Typical Equation of States
Peng-Robinson (PR) EOS
Redlich-Kwong (RK) EOS
Haydon O’Conell (HOC) EOS
Thermodynamic Model – NRTL
NRTL
21
NRTL – Binary Parameters
Click “NRTL” and then built-in binary parameters
appear automatically if available.
22
Access Properties Models and
Parameters
Review Databank Data
23
Review Databank Data
Including:
Ideal gas heat of formation at 298.15 K
Ideal gas Gibbs free energy of formation at
298.15 K
Heat of vaporization at TB
Normal boiling point
Standard liquid volume at 60°F
….
Description of each parameter
24
Pure Component
Temperature-Dependent Properties
CPIGDP-1
ideal gas heat capacity
CPSDIP-1
Solid heat capacity
DNLDIP-1
Liquid density
DHVLDP-1
Heat of vaporization
PLXANT-1
Extended Antoine Equation
MULDIP
Liquid viscosity
KLDIP
Liquid thermal conductivity
SIGDIP
Liquid surface tension
UFGRP
UNIFAC functional group
25
Example: PLXANT-1
(Extended Antoine Equation)
Corresponding Model
Click “↖?” and then click where you don’t know
?
26
Example: CPIGDP-1
(Ideal Gas Heat Capacity Equation)
Corresponding Model
?
27
Basic Input---Summary
• The minimum required inputs to run a simulation
are:
–
–
–
–
–
Setup
Components
Properties
Streams
Blocks
Property Analysis
Process Simulation
28
Introduction to Aspen Plus
Part 3: Property analysis
29
Overview of Property Analysis
Use this form
Pure
Binary
Residue
Ternary
Azeotrope
To generate
Tables and plots of pure component properties as a function of temperature
and pressure
Txy, Pxy, or Gibbs energy of mixing curves for a binary system
Residue curve maps
Ternary maps showing phase envelope, tie lines, and azeotropes of ternary
systems
This feature locates all the azeotropes that exist among a specified set of
components.
Ternary diagrams in Aspen Distillation Synthesis feature: Azeotropes,
Ternary Maps Distillation boundary, Residue curves or distillation curves, Isovolatility curves,
Tie lines, Vapor curve, Boiling point
***When you start properties analysis, you MUST specify components ,
thermodynamic model and its corresponding parameters. (Refer to Part 2)
30
Find Components
Component ID : just for distinguishing in Aspen.
Type : Conventional, Solid….etc
Component name : real component name
Formula : real component formula
31
Find Components
TIP 1: For common components, you can
enter directly the common name or molecular
equation of the components in “component
ID”.
(like water, CO2, CO, Chlorine…etc)
32
Find Components
TIP 2: If you know the component name
(like N-butanol, Ethanol….etc), you can
enter it in “component name”.
33
Find Components
TIP 3: You can also enter the formula of the
component. (Be aware of the isomers)
You can also click “Find” to search for
component of given CAS number,
molecular weight without knowing its
molecular formula, or if you don’t know the
exactly component name
34
Select Thermodynamic Model
Select NRTL
35
Check Binary Parameter
Properties
Parameters
NRTL-1
Click This, it will automatically change to
red if binary parameter exists.
36
Find Components
TIP 2: If you know the component name
(like N-butanol, Ethanol….etc), you can
enter it in “component name”.
37
Find Components
You can enter
the way of
searching…
38
Properties Analysis – Pure Component
39
Available Properties
Property (thermodynamic)
Property (transport)
Availability
Free energy
Constant pressure
Enthalpy
heat capacity
Heat capacity ratio
Fugacity coefficient
Constant volume heat Fugacity coefficient
capacity
pressure correction
Free energy departure
Vapor pressure
Free energy departure
Density
pressure correction
Enthalpy departure
Entropy
Enthalpy departure
Volume
pressure correction
Enthalpy of
Sonic velocity
vaporization
Entropy departure
Thermal conductivity
Surface tension
Viscosity
40
Example1: CP (Heat Capacity)
1. Select property (CP)
4. Specify range of temperature
2. Select phase
5. Specify pressure
Add “N-butyl-acetate”
3. Select component
6. Select property method
7. click Go to generate the results
41
Example1: Calculation Results of CP
Data results
42
Properties Analysis – Binary Components
Binary Component Properties Analysis
Use this Analysis type To generate
Temperature-compositions diagram at
Txy
constant pressure
Pressure-compositions diagram at
Pxy
constant temperature
Gibbs energy of mixing diagram as a
function of liquid compositions. The
Aspen Physical Property System uses this
Gibbs energy of mixing
diagram to determine whether the
binary system will form two liquid phases
at a given temperature and pressure.
Example: T-XY
1. Select analysis type (Txy)
2. Select two component
2. Select phase (VLE, VLLE)
5. Specify pressure
3. Select compositions basis
6. Select property method
4. Specify composition range
7. click Go to generate the results
Example: calculation result of T-XY
Data results
Example: Generate XY plot
Click “plot wizard” to generate XY plot
Example: Generate XY plot (cont’d)
Properties Analysis – Ternary
(add one new components)
Properties Analysis – Ternary
(Check NRTL binary parameter)
3 components -> 3 set of binary parameter
(How about 4 components??)
Properties Analysis – Ternary
Ternary Map
1. Select three component
4. Select phase (VLE, LLE)
2. Specify number of tie line
5. Specify pressure
3. Select property method
6. Specify temperature
(if LLE is slected)
7. click Go to generate the results
Calculation Result of Ternary Map (LLE)
Data results
Property Analysis
–
Conceptual
Design
(Optional)
Use this form
To generate
Binary
Tables and plots of pure component properties as a function of temperature
and pressure
Txy, Pxy, or Gibbs energy of mixing curves for a binary system
Residue
Residue curve maps
Pure
Ternary
Azeotrope
Ternary maps showing phase envelope, tie lines, and azeotropes of ternary
systems
This feature locates all the azeotropes that exist among a specified set of
components.
Ternary diagrams in Aspen Distillation Synthesis feature: Azeotropes,
Ternary Maps Distillation boundary, Residue curves or distillation curves, Isovolatility curves,
Tie lines, Vapor curve, Boiling point
54
Conceptual Design
Azeotrope Analysis
Azeotrope Analysis
1. Select components (at least two)
2. Specify pressure
3. Select property method
6. click Report to generate the results
4. Select phase (VLE, LLE)
5. Select report Unit
Error Message
Close analysis input dialog box (pure or binary analysis)
Azeotrope Analysis Report
Ternary Maps
Ternary Maps
3. Select property method
1. Select three components
4. Select phase (VLE, LLE)
2. Specify pressure
5. Select report Unit
6. Click Ternary Plot to generate the results
6. Specify temperature of LLE
(If liquid-liquid envelope is selected)
Ternary Maps
Change pressure or
temperature
Ternary Plot Toolbar:
Add Tie line, Curve,
Marker…
Introduction to Aspen Plus
Part 4: Running simulation
Simple Units
(Mixer, Pump, valve, flash, heat exchanger)
63
Example 1: Calculate the mixing
properties of two stream
1
2
4
3
Mixer
Mole Flow kmol/hr
WATER
BUOH
BUAC
Total Flow kmol/hr
Temperature C
Pressure bar
Enthalpy kcal/mol
Entropy cal/mol-K
Density kmol/cum
Pump
1
2
3
4
10
0
0
10
50
1
?
?
?
0
9
6
15
80
1
?
?
?
?
?
?
?
?
1
?
?
?
?
?
?
?
?
10
?
?
?
64
Setup – Specification
Select Flowsheet
65
Reveal Model Library
View|| Model Library
or press F10
66
Adding a Mixer
Click “one of icons”
and then click again on the flowsheet window
Remark: The shape of the icons are meaningless
67
Adding Material Streams
Click “Materials” and then click
again on the flowsheet window
68
Adding Material Streams (cont’d)
When clicking the mouse on the flowsheet window,
arrows (blue and red) appear.
69
Adding Material Streams (cont’d)
When moving the mouse on the arrows, some description appears.
Red arrow(Left) Feed
(Required; one ore more
if mixing material
streams)
Red arrow(Right):
Blue arrow: Water
Product (Required; if
decant for Free water
mixing material streams) of dirty water.
70
Adding Material Streams (cont’d)
After selecting “Material Streams”, click and pull a stream line.
Repeat it three times to generate three stream lines.
71
Reconnecting Material Streams
(Feed Stream)
Right Click on the stream and
select Reconnect Destination
72
Reconnecting Material Streams
(Product Stream)
Right Click on the stream and
select Reconnect Source
B1
1
3
2
73
Specifying Feed Condition
Right Click on the stream
and select Input
74
Specifying Feed Condition (cont’d)
1
2
75
Specifying Input of Mixer
Right Click on the block and select Input
76
Specifying Input of Mixer (cont’d)
Specify Pressure and valid phase
77
Run Simulation
Click ► to run the simulation
Run
Start or continue calculations
Step
Step through the flowsheet one block at a time
Stop
Pause simulation calculations
Reinitialize
Purge simulation results
Check “simulation status”
“Required Input Complete” means the input is ready to run simualtion
78
Status of Simulation Results
Message
Results available
Results with warnings
Means
The run has completed normally, and results are
present.
Results for the run are present. Warning
messages were generated during the
calculations. View the Control Panel or History
for messages.
Results with errors
Results for the run are present. Error messages
were generated during the calculations. View the
Control Panel or History for messages.
Input Changed
Results for the run are present, but you have
changed the input since the results were
generated. The results may be inconsistent with
the current input.
79
Stream Results
Right Click on the block and
select Stream Results
80
Pull down the list and select
“Full” to show more properties
results.
Enthalpy and Entropy
Substream: MIXED
Mole Flow kmol/hr
WATER
BUOH
BUAC
Total Flow kmol/hr
Total Flow kg/hr
Total Flow cum/hr
Temperature C
Pressure bar
Vapor Frac
Liquid Frac
Solid Frac
Enthalpy kcal/mol
Enthalpy kcal/kg
Enthalpy Gcal/hr
Entropy cal/mol-K
Entropy cal/gm-K
Density kmol/cum
Density kg/cum
Average MW
Liq Vol 60F cum/hr
1
2
3
10
0
0
10
180.1528
0.18582
50
2
0
1
0
-67.81
-3764.03
-0.6781
-37.5007
-2.0816
53.81564
969.5038
18.01528
0.1805
0
9
6
15
1364.066
1.74021
80
1
0
1
0
-94.3726
-1037.77
-1.41559
-134.947
-1.48395
8.619647
783.851
90.93771
1.617386
10
9
6
25
1544.218
1.870509
70.08758
1
0
1
0
-83.7476
-1355.82
-2.09369
-95.6176
-1.54799
13.36534
825.5604
61.76874
1.797886
81
Change Units of Calculation Results
82
Setup – Defining Your Own Units Set
83
Setup – Report Options
84
Stream Results with Format of
Mole Fraction
85
Add Pump Block
86
Add A Material Stream
87
Connect Streams
88
Pump – Specification
1. Select “Pump” or “turbine”
2. Specify pump outlet specificatio
(pressure, power)
3. Efficiencies (Default: 1)
89
Run Simulation
Click ► to generate the results
Check “simulation status”
“Required Input Complete”
90
Block Results (Pump)
Right Click on the block and select Results
91
92
Streams Results
93
Calculation Results
(Mass and Energy Balances)
1
2
4
3
Mixer
Pump
1
2
3
Mole Flow kmol/hr
WATER
10
0
10
BUOH
0
9
9
BUAC
0
6
6
Total Flow kmol/hr
10
15
25
Temperature C
50
80
70.09
Pressure bar
1
1
1
Enthalpy kcal/mol -67.81 -94.37 -83.75
Entropy cal/mol-K -37.50 -134.95 -95.62
Density kmol/cum 969.50 783.85 825.56
4
10
9
6
25
71.20
10
-83.69
-95.46
824.29
94
Exercise
1
2
3
4
Mixer
Mole Flow kmol/hr
Water
Ethanol
Methanol
Total Flow kmol/hr
Temperature C
Pressure bar
Enthalpy kcal/mol
Entropy cal/mol-K
Density kmol/cum
6
5
Pump
1
2
3
4
5
6
10
0
0
10
50
1
?
?
?
0
5
0
15
70
1
?
?
?
0
0
15
15
40
1
?
?
?
?
?
?
?
?
1
?
?
?
?
?
?
?
?
4
?
?
?
?
?
?
?
?
2
?
?
?
Please use Peng-Robinson EOS to solve this problem.
95
Example 2: Flash Separation
120
T-x
T-y
Saturated Feed
P=1atm
F=100 kmol/hr
zwater=0.5
zHAc=0.5
o
T=105 C
P=1atm
T ( C)
115
110
105
100
0.0
What are flowrates and compositions of the two outlets?
0.2
0.4
0.6
xWater and yWater
0.8
1.0
Input Components
Thermodynamic Model: NRTL-HOC
Check Binary Parameters
Association parameters of HOC
Binary Parameters of NRTL
Binary Analysis
T-xy plot
1. Select analysis type (Txy)
2. Select two component
3. Select compositions basis
2. Select phase (VLE, VLLE)
5. Specify pressure
6. Select property method
4. Specify composition range
7. click Go to generate the results
Calculation Result of T-xy
Data results
Generate xy plot
Generate xy plot (cont’d)
Add Block: Flash2
Add Material Stream
Specify Feed Condition
Saturated Feed
(Vapor fraction=0)
P=1atm
F=100 kmol/hr
zwater=0.5
zHAc=0.5
Block Input: Flash2
Flash2: Specification
T=105 C
P=1atm
Required Input Complete
Click ► to run simulation
**Before running simulation, property
analysis should be closed.
Stream Results
Stream Results (cont’d)
42.658 kmol/hr
zwater=0.501
zHAc=0.409
Saturated Feed
P=1atm
F=100 kmol/hr
zwater=0.5
zHAc=0.5
T=105 C
P=1atm
57.342 kmol/hr
zwater=0.432
zHAc=0.568
HEAT EXCHANGE
熱物流
入口温度：200℃、入口壓力：0.4 MPa
流量：10000kg/hr
组成：苯 50%，苯乙烯 20%，水 10%
冷卻水
入口温度：20℃、入口压力：1.0 MPa
流量：60000 kg/hr。
熱流出口氣相分率為 0
（飽和液相）
COMPONENTS – SPECIFICATION
116
Thermodynamic Model – NRTL
117
ADD BLOCK: HEATX
Feeds Conditions
CLD-IN
HOT-IN
BLOCK INPUT
Check result
121
Check result
122
Introduction to Aspen Plus
Part 5: Running simulation
Reactor Systems
(RGIBBS, RPLUG,RCSTR)
123
Equilibrium Reactor: RGIBBS
RGIBBS unit predicts the product by
minimizing GIBBS energy in the system
It is very Useful When…:
1. Reaction Kinetics are unknown.
2. There are lots of products
124
Equilibrium Reactor: RGIBBS
Reactions:
CO  3H 2  CH 4  H 2O
CO2  4 H 2  CH 4  2 H 2O
CO  H 2O  CO2  H 2
Fresh Feed
Flow rate
1000 (kmol/h)
CO
0.2368
H2
0.7172
H2O
0.0001
CH4
0.0098
CO2
0.0361
T=300 k
P=470 psia
125
Equilibrium Reactor: RGIBBS
126
Equilibrium Reactor: RGIBBS
Inside the Block:
Check result
128
KINETICS REACTORS: RPLUG
Reaction :Exothermic & reversible
CO  H 2O  CO2  H 2
H  41.09( KJ / mol )
kmol
Rate  k f YCOYH 2O  k rYCO2 YH 2 (
)
kgcat  s
 47400
k f  51.545 exp(
)
RT
 85458
k r  3922.1exp(
)
RT
Rate [=] Kmol/Kgcat/s
Activation Energy [=] KJ/Kmol
KINETICS REACTORS: RPLUG
Reaction :Exothermic & reversible
CO  H 2O  CO2  H 2
Fresh Feed
Flow rate
200 (mol/h)
CO
0.030
H2
0.430
H2O
0.392
CO2
0.148
H  41.09( KJ / mol )
Catalyst Loading = 0.1865 Kg
Bed Voidage = 0.8928
Feed Temperature = 583K
Feed Pressure = 1 bar
Reactor Length = 10 m
Reactor Diameter = 5m
KINETICS REACTORS: RPLUG
Feed Stream:
KINETICS REACTORS: RPLUG
Reaction Setting:
KINETICS REACTORS: RPLUG
Reaction Setting:
KINETICS REACTORS: RPLUG
RPLUG Setting:
KINETICS REACTORS: RPLUG
RPLUG Setting:
KINETICS REACTORS: RPLUG
RPLUG Setting:
Check result
137
Check result
138
Check result
Select Reactor Length column
Plot -> x-Axis variable
Select Temperature Column
Plot -> y-Axis variable
Display Plot
139
TEMPERATURE K
585.0 587.5 590.0 592.5 595.0 597.5 600.0 602.5 605.0 607.5
Check result
0.0
Block B2 (RPlug) Profiles Process Stream
Temperature MIXED
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0 4.5 5.0 5.5 6.0
Reactor length MIXED meter
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
140
Check result
141
Check result
Select Reactor Length column
Plot -> x-Axis variable
Select all other columns
Plot -> y-Axis variable
Display Plot
142
Check result
0.35
0.4
0.45
0.5
Block B2 (RPlug) Profiles Process Stream
fraction MIXED CO
fraction MIXED H2O
fraction MIXED CO2
fraction MIXED H2
0.05
0.1
0.15
0.2
0.25
0.3
Mole
Mole
Mole
Mole
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5 5.0 5.5
6.0
Reactor length MIXED meter
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
KINETICS REACTORS: RCSTR
Reaction :Exothermic & Irreversible
Aniline + Hydrogen  Cyclohexylamine (CHA)
C6H7N + 3H2  C6H13N
Reactor Conditions
Reactor :
Reactor
Pressure
595 psi
Temperature
250 F
Volume
1200 ft3
condition
Reactor type
Reactor liquid level
Vertical cylindrical vessel
80%
Reactor Conditions Input
Reaction Kinetics
Reaction rate :
RCHA  kVRCACH
Where
ft 3
VR: reactor volume
lbmole 3
ft
CA: concentration of Aniline lbmole
ft
CH: concentration of Hydrogen
• Reaction kinetics :
k  k0 exp( E
E  2000 Btu
k0  10
8
RT
lbmole
)
Where
T : temperature (R)
E : activity energy
3
Reaction Kinetics Input
Reaction Kinetics Input
Reaction Kinetics Input
Feeds Conditions
Two fresh feed stream :
Aniline feed
Hydrogen feed
mole rate
100 lbmolhr 1
400 lbmolhr 1
temperature
100 F
100 F
650 psia
650 psia
pressure
Feeds Conditions
Check result
Question:
(1) Compare the conversion between RSTOIC and RCSTR.
(2) Compare the net duty inside the RSTOIC and RCSTR
153
Introduction to Aspen Plus
Part 6: Running simulation
Distillation Process
(DSTWU, RADFRAC)
154
Distillation Separation
1
2
RR ?
xwater=0.99
20
Saturated Feed
P=1.2atm
F=100 kmol/hr
zwater=0.5
zHAc=0.5
39
QR ?
40
xHAc=0.99
• There are two degrees of
freedom to manipulate
distillate composition and
bottoms composition to
manipulate the distillate and
bottoms compositions.
• If the feed condition and the
number of stages are given,
how much of RR and QR are
required to achieve the
specification.
Distillation Separation
Example :
A mixture of benzene and toluene containing 40 mol% benzene
is to be separated to dive a product containing 90 mol%
benzene at the top, and no more than 10% benzene in bottom
product. The feed enters the column as saturated liquid, and
the vapor leaving the column which is condensed but not
cooled, provide reflux and product. It is proposed to operate
the unit with a reflux ratio of 3 kmol/kmol product. Please
find:
(1) The number of theoretical plates.
(2) The position of the entry.
(Problem is taken from Coulson & Richardson’s Chemical
Engineering, vol 2, Ex 11.7, p.564)
1. By what you learned in Material balance and
unit operation
From Overall Material Balance:
100 = D+B
1
xben=0.9
37.5
Saturated Feed
P=100 Kpa
F=100 kmol/hr
xben=0.4
xtol=0.6
From Benzene Balance:
100*0.4 = 0.9 * D+ 0.1* B
Thus, D=37.5 and B=62.5.
n
xben<0.1
62.5
1. By what you learned in Material balance and
unit operation
From thermodynamic phase equilibrium, and the calculation of operating line:
We can get the number of theoretical plate to be 7.
2. By the shortcut method in Aspen Plus (DISTWU)
(Add components)
Built in the components
2. By the shortcut method in Aspen Plus (DISTWU)
(Select property method)
Select NRTL
2. By the shortcut method in Aspen Plus (DISTWU)
(Select property method)
Check the binary parameters
2. By the shortcut method in Aspen Plus (DSTWU)
Add the unit “DSTWU”
The red arrows are the required material stream!
2. By the shortcut method in Aspen Plus (DSTWU)
Connect the required material stream
2. By the shortcut method in Aspen Plus (DSTWU)
“Feed1” Stream specification
2. By the shortcut method in Aspen Plus
(Column Specification)
From the problem Assume no pressure drop
Inside the column
2. By the shortcut method in Aspen Plus
(Column Specification)
Light Key recovery
= (mol of light component in distillate) /
(mol of light component in feed)
= (37.5*0.9)/(100*0.4)
= 0.84375
2. By the shortcut method in Aspen Plus
(Column Specification)
Heavy Key recovery
= (mol of heavy component in distillate)
/ (mol of heavy component in feed)
= (37.5*0.1)/(100*0.6)
= 0.0625
2. By the shortcut method in Aspen Plus
(Column Specification)
Get results by varying the
number of stages. (Initial
Guess)
2. By the shortcut method in Aspen Plus (DSTWU)
RUN THE SIMULATION
2. By the shortcut method in Aspen Plus
(Stream Results)
Click right button on the unit, and select “Stream
Results”
2. By the shortcut method in Aspen Plus
(Stream Results)
The required product
quality
2. By the shortcut method in Aspen Plus
(RR vs number of stage)
For RR=3, at least 7
theoretical stages are
required.
3. More rigorous method in Aspen Plus (RADFRAC)
Add the unit “RADFRAC”
The red arrows are the required material stream!
3. More rigorous method in Aspen Plus (RADFRAC)
Connect the required material stream
3. More rigorous method in Aspen Plus (RADFRAC)
(Feed Specification)
Same as Case 2
3. More rigorous method in Aspen Plus (RADFRAC)
(Column Specification)
Double click left button on the unit….
3. More rigorous method in Aspen Plus (RADFRAC)
(Column Specification)
7 stages from previous
calculation.
RR=3 from the problem, distillate rate = 37.5
(kmol/h) from previous calculation
3. More rigorous method in Aspen Plus (RADFRAC)
(Column Specification)
Specify the feed stage.
3. More rigorous method in Aspen Plus (RADFRAC)
(Column Specification)
Specify the pressure at the top of column
3. More rigorous method in Aspen Plus (RADFRAC)
(Calculation of tray size—Tray Sizing)
3. More rigorous method in Aspen Plus (RADFRAC)
(Calculation of tray size—Tray Sizing)
*Calculation from 2th tray from the top to
2th tray from the bottom. (WHY??)
*Select a tray type.
3. More rigorous method in Aspen Plus (RADFRAC)
(Pressure drop calculation– Tray Rating)
3. More rigorous method in Aspen Plus (RADFRAC)
(Pressure drop calculation– Tray Rating)
*Calculation from 2th tray from the top to
2th tray from the bottom. (WHY??)
*Initial guess of the tray size
3. More rigorous method in Aspen Plus (RADFRAC)
(Pressure drop calculation– Tray Rating)
3. More rigorous method in Aspen Plus (RADFRAC)
(Stream Results)
Click right button on the unit, and select “Stream
Results”
3. More rigorous method in Aspen Plus (RADFRAC)
(Stream Results)
Different from the shorcut method.
(WHY??)
Introduction to Aspen Plus
Part 7: Running simulation
(Additional)
Design, spec, and vary in RADFRAC
187
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
What do we want??
--- 90% Benzene at top.
Select “Mole Purity”…
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
What do we want??
--- 90% Benzene at top.
Select “Mole Purity”…
And the target is 0.9.
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Select “Benzene”
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Select the distillate stream
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Add a Vary
(1 Design Spec
1 Vary)
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Varying Reflux ratio to
reach the design target.
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Specify the varying range.
(Should contain the initial value)
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
2nd Design Spec
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
What do we want??
--- 10% Benzene at bot.
Select “Mole Purity”…
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
What do we want??
--- 10% Benzene at bot.
Select “Mole Purity”…
And the target is 0.1.
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Select the Benzene
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Select the bottom stream
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
2nd Vary
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
Varying distillate rate to
reach the design target.
Specify the varying range.
(Should contain the initial value)
3. More rigorous method in Aspen Plus (RADFRAC)
(Design , Spec and Vary)
RUN THE SIMULATION,
and click right button on
the unit, select “Stream
results”
3. More rigorous method in Aspen Plus (RADFRAC)
(Stream Results)
The required product
quality
3. More rigorous method in Aspen Plus (RADFRAC)
(Column Results--top)
Calculated Reflux Ratio = 6.14
(from problem: 3)
3. More rigorous method in Aspen Plus (RADFRAC)
(Column Results--bottom)
The required heat duty for
separation is 2341.8 (KW)
3. More rigorous method in Aspen Plus (RADFRAC)
(Profile Inside the Column)
T : Temperature
P : Pressure
F : Liquid and vapor flow rate.
Q: Heat Duty
3. More rigorous method in Aspen Plus (RADFRAC)
(Profile Inside the Column)
You can select the vapor or
liquid composition profile.
(also in mole or mass basis)
3. More rigorous method in Aspen Plus (RADFRAC)
(Plotting Temp. Profile)
Select the column “Stage”
Click “Plot”
Select “X-axis variable”
3. More rigorous method in Aspen Plus (RADFRAC)
(Plotting Temp. Profile)
Select the column “Temp.”
Click “Plot”
Select “Y-axis variable”
3. More rigorous method in Aspen Plus (RADFRAC)
(Plotting Temp. Profile)
Then, select “Display
Plot”
3. More rigorous method in Aspen Plus (RADFRAC)
(Plotting Temp. Profile)
Exercise
Example:
Typically, 90 mol% product purity is not enough for a product to
sale. In the same problem, assume the number of stages
increase to 10. Try the following exercises:
(1) Is it possible to separate the feed to 95 mol% of benzene in
the distillate, and less than 5% of benzene in the bottom
product? If yes, what is the RR and Qreb?
(2) As in (1), is it possible to separate the feed to 99 mol% of
benzene in the distillate, and less than 1% of benzene in the
bottom product? If yes, what is the RR and Qreb?
(3) As in (2), if no, how many number of stages is required to
reach this target?
(Hint: Use design, spec, and vary to do this problem)
Thanks for your attention!
PSE Laboratory
Department of Chemical Engineering
Nation Taiwan University
(綜合 room 402)
214