introduction to aspen plus --2014.pdf
TRANSCRIPT
Introduction to Aspen Plus
Speaker: Bor-Yih Yu(余柏毅)
Date: 2013/09/02
PSE Laboratory
Department of Chemical Engineering
Nation Taiwan University
(綜合 room 402)
Edited by: 程建凱/吳義章/余柏毅
2
Introduction to Aspen Plus
Part 1: Introduction
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.
3 Ref: http://www.aspentech.com/products/aspen-plus.cfm
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)
Ref: Aspen Plus® Product Brochure
4
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
9
Part 2: Startup
Start with Aspen Plus
Aspen Plus User Interface
Aspen Plus Startup
11
Interface of Aspen Plus
Process Flowsheet Windows
Model Library (View| Model Library )
Stream
Help
Setup
Components
Properties
Streams
Blocks
Data Browser
Next
Check Result
Stop
Reinitialize
Step
Start
Control Panel
Process Flowsheet Windows
Model Library (View| Model Library )
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
18
Example 1: water - benzene
Example 2: benzene - toluene
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
23
Review Databank Data
Review Databank Data
Description of each parameter
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 ….
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
29
Introduction to Aspen Plus
Part 3: Property analysis
Overview of Property Analysis Use this form To generate
Pure Tables and plots of pure component properties as a function of temperature and pressure
Binary Txy, Pxy, or Gibbs energy of mixing curves for a binary system
Residue Residue curve maps
Ternary Ternary maps showing phase envelope, tie lines, and azeotropes of ternary systems
Azeotrope This feature locates all the azeotropes that exist among a specified set of components.
Ternary Maps Ternary diagrams in Aspen Distillation Synthesis feature: Azeotropes, Distillation boundary, Residue curves or distillation curves, Isovolatility curves, Tie lines, Vapor curve, Boiling point
30
***When you start properties analysis, you MUST specify components ,
thermodynamic model and its corresponding parameters. (Refer to Part 2)
Find Components
31
Component ID : just for distinguishing in Aspen.
Type : Conventional, Solid….etc
Component name : real component name
Formula : real component formula
Find Components
32
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)
Find Components
33
TIP 2: If you know the component name
(like N-butanol, Ethanol….etc), you can
enter it in “component name”.
Find Components
34
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
Select Thermodynamic Model
35
Select NRTL
Check Binary Parameter
36
Click This, it will automatically change to
red if binary parameter exists.
Properties
Parameters
NRTL-1
Find Components
37
TIP 2: If you know the component name
(like N-butanol, Ethanol….etc), you can
enter it in “component name”.
Find Components
38
You can enter
the way of
searching…
Properties Analysis – Pure Component
39
Available Properties
Property (thermodynamic) Property (transport)
Availability Free energy Thermal conductivity
Constant pressure heat capacity
Enthalpy Surface tension
Heat capacity ratio Fugacity coefficient Viscosity
Constant volume heat capacity
Fugacity coefficient pressure correction
Free energy departure Vapor pressure
Free energy departure pressure correction
Density
Enthalpy departure Entropy
Enthalpy departure pressure correction
Volume
Enthalpy of vaporization
Sonic velocity
Entropy departure 40
Example1: CP (Heat Capacity)
1. Select property (CP)
2. Select phase
3. Select component
4. Specify range of temperature
5. Specify pressure
6. Select property method
7. click Go to generate the results
Add “N-butyl-acetate”
41
Example1: Calculation Results of CP
Data results 42
Properties Analysis – Binary Components
Binary Component Properties Analysis
Use this Analysis type To generate
Txy Temperature-compositions diagram at constant pressure
Pxy Pressure-compositions diagram at constant temperature
Gibbs energy of mixing
Gibbs energy of mixing diagram as a function of liquid compositions. The Aspen Physical Property System uses this 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 phase (VLE, VLLE)
2. Select two component
4. Specify composition range
5. Specify pressure
6. Select property method
3. Select compositions basis
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
4. Select phase (VLE, LLE)
1. Select three component
5. Specify pressure
3. Select property method
2. Specify number of tie line
7. click Go to generate the results
6. Specify temperature
(if LLE is slected)
Calculation Result of Ternary Map (LLE)
Data results
Property Analysis – Conceptual Design
Use this form To generate
Pure Tables and plots of pure component properties as a function of temperature and pressure
Binary Txy, Pxy, or Gibbs energy of mixing curves for a binary system
Residue Residue curve maps
Ternary Ternary maps showing phase envelope, tie lines, and azeotropes of ternary systems
Azeotrope This feature locates all the azeotropes that exist among a specified set of components.
Ternary Maps Ternary diagrams in Aspen Distillation Synthesis feature: Azeotropes, Distillation boundary, Residue curves or distillation curves, Isovolatility curves, Tie lines, Vapor curve, Boiling point
54
(Optional)
Conceptual Design
Azeotrope Analysis
Azeotrope Analysis
4. Select phase (VLE, LLE)
1. Select components (at least two) 2. Specify pressure
3. Select property method
5. Select report Unit
6. click Report to generate the results
Error Message
Close analysis input dialog box (pure or binary analysis)
Azeotrope Analysis Report
Ternary Maps
Ternary Maps
4. Select phase (VLE, LLE) 1. Select three components
2. Specify pressure
3. Select property method
5. Select report Unit
6. Specify temperature of LLE
(If liquid-liquid envelope is selected)
6. Click Ternary Plot to generate the results
Ternary Maps
Ternary Plot Toolbar:
Add Tie line, Curve,
Marker…
Change pressure or
temperature
63
Introduction to Aspen Plus
Part 4: Running simulation
Simple Units
(Mixer, Pump, valve, flash, heat exchanger)
Example 1: Calculate the mixing properties of two stream
1
23
4
Mixer Pump
1 2 3 4
Mole Flow kmol/hr
WATER 10 0 ? ?
BUOH 0 9 ? ?
BUAC 0 6 ? ?
Total Flow kmol/hr 10 15 ? ?
Temperature C 50 80 ? ?
Pressure bar 1 1 1 10
Enthalpy kcal/mol ? ? ? ?
Entropy cal/mol-K ? ? ? ?
Density kmol/cum ? ? ? ? 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.
Blue arrow: Water
decant for Free water
of dirty water.
Red arrow(Left) Feed
(Required; one ore more
if mixing material
streams)
Red arrow(Right):
Product (Required; if
mixing material streams)
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
2
3
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
Check “simulation status”
“Required Input Complete” means the input is ready to run simualtion
Run Start or continue calculations
Step Step through the flowsheet one block at a time
Stop Pause simulation calculations
Reinitialize Purge simulation results
78
Status of Simulation Results
Message Means
Results available The run has completed normally, and results are present.
Results with warnings
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
1 2 3
Substream: MIXED Mole Flow kmol/hr
WATER 10 0 10
BUOH 0 9 9
BUAC 0 6 6
Total Flow kmol/hr 10 15 25
Total Flow kg/hr 180.1528 1364.066 1544.218
Total Flow cum/hr 0.18582 1.74021 1.870509
Temperature C 50 80 70.08758
Pressure bar 2 1 1
Vapor Frac 0 0 0
Liquid Frac 1 1 1
Solid Frac 0 0 0
Enthalpy kcal/mol -67.81 -94.3726 -83.7476
Enthalpy kcal/kg -3764.03 -1037.77 -1355.82
Enthalpy Gcal/hr -0.6781 -1.41559 -2.09369
Entropy cal/mol-K -37.5007 -134.947 -95.6176
Entropy cal/gm-K -2.0816 -1.48395 -1.54799
Density kmol/cum 53.81564 8.619647 13.36534
Density kg/cum 969.5038 783.851 825.5604
Average MW 18.01528 90.93771 61.76874
Liq Vol 60F cum/hr 0.1805 1.617386 1.797886
Pull down the list and select
“Full” to show more properties
results.
81
Enthalpy and Entropy
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
2. Specify pump outlet specification
(pressure, power)
1. Select “Pump” or “turbine”
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
23
4
Mixer Pump
1 2 3 4
Mole Flow kmol/hr
WATER 10 0 10 10
BUOH 0 9 9 9
BUAC 0 6 6 6
Total Flow kmol/hr 10 15 25 25
Temperature C 50 80 70.09 71.20
Pressure bar 1 1 1 10
Enthalpy kcal/mol -67.81 -94.37 -83.75 -83.69
Entropy cal/mol-K -37.50 -134.95 -95.62 -95.46
Density kmol/cum 969.50 783.85 825.56 824.29 94
Exercise
1
2 46
Mixer Pump3
5
1 2 3 4 5 6
Mole Flow kmol/hr
Water 10 0 0 ? ? ?
Ethanol 0 5 0 ? ? ?
Methanol 0 0 15 ? ? ?
Total Flow kmol/hr 10 15 15 ? ? ?
Temperature C 50 70 40 ? ? ?
Pressure bar 1 1 1 1 4 2
Enthalpy kcal/mol ? ? ? ? ? ?
Entropy cal/mol-K ? ? ? ? ? ?
Density kmol/cum ? ? ? ? ? ?
95 Please use Peng-Robinson EOS to solve this problem.
Example 2: Flash Separation
Saturated Feed
P=1atm
F=100 kmol/hr
zwater=0.5
zHAc=0.5
T=105 C
P=1atm
What are flowrates and compositions of the two outlets?
0.0 0.2 0.4 0.6 0.8 1.0100
105
110
115
120
T (
oC
)x
Water and y
Water
T-x
T-y
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 phase (VLE, VLLE)
2. Select two component
4. Specify composition range
5. Specify pressure
6. Select property method 3. Select compositions basis
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)
Saturated Feed
P=1atm
F=100 kmol/hr
zwater=0.5
zHAc=0.5
T=105 C
P=1atm
42.658 kmol/hr
zwater=0.501
zHAc=0.409
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)
116
COMPONENTS – SPECIFICATION
117
Thermodynamic Model – NRTL
ADD BLOCK: HEATX
Feeds Conditions
HOT-IN CLD-IN
BLOCK INPUT
121
Check result
122
Check result
123
Introduction to Aspen Plus
Part 5: Running simulation
Reactor Systems
(RGIBBS, RPLUG,RCSTR)
124
Equilibrium Reactor: RGIBBS
1. Reaction Kinetics are unknown.
2. There are lots of products
RGIBBS unit predicts the product by
minimizing GIBBS energy in the system
It is very Useful When…:
125
Equilibrium Reactor: RGIBBS
222
2422
242
24
3
HCOOHCO
OHCHHCO
OHCHHCO
Reactions:
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
126
Equilibrium Reactor: RGIBBS
Equilibrium Reactor: RGIBBS
Inside the Block:
128
Check result
KINETICS REACTORS: RPLUG
Reaction :Exothermic & reversible
222 HCOOHCO )/(09.41 molKJH
)85458
exp(1.3922
)47400
exp(545.51
)(222
RTk
RTk
skgcat
kmolYYkYYkRate
r
f
HCOrOHCOf
Rate [=] Kmol/Kgcat/s
Activation Energy [=] KJ/Kmol
KINETICS REACTORS: RPLUG
Reaction :Exothermic & reversible
222 HCOOHCO )/(09.41 molKJH
Catalyst Loading = 0.1865 Kg
Bed Voidage = 0.8928
Feed Temperature = 583K
Feed Pressure = 1 bar
Reactor Length = 10 m
Reactor Diameter = 5m
Fresh Feed
Flow rate 200 (mol/h)
CO 0.030
H2 0.430
H2O 0.392
CO2 0.148
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:
137
Check result
138
Check result
139
Check result
Select Reactor Length column
Plot -> x-Axis variable
Select Temperature Column
Plot -> y-Axis variable
Display Plot
140
Check result Block B2 (RPlug) Profiles Process Stream
Reactor length MIXED meter
TE
MP
ER
AT
UR
E K
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 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0
58
5.0
58
7.5
59
0.0
59
2.5
59
5.0
59
7.5
60
0.0
60
2.5
60
5.0
60
7.5
Temperature MIXED
141
Check result
142
Check result
Select Reactor Length column
Plot -> x-Axis variable
Select all other columns
Plot -> y-Axis variable
Display Plot
Check result Block B2 (RPlug) Profiles Process Stream
Reactor length MIXED meter
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 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0
0.0
50
.10
.15
0.2
0.2
50
.30
.35
0.4
0.4
50
.5
Mole fraction MIXED CO
Mole fraction MIXED H2O
Mole fraction MIXED CO2
Mole fraction MIXED H2
KINETICS REACTORS: RCSTR
Reaction :Exothermic & Irreversible
Aniline + Hydrogen Cyclohexylamine (CHA)
C6H7N + 3H2 C6H13N
Reactor Conditions
Reactor :
Reactor
condition
Reactor type
Reactor liquid level
595 psi
250 F
1200 ft3
Temperature
Volume
Vertical cylindrical vessel
80%
Pressure
Reactor Conditions Input
Reaction Kinetics
CHA R A HR kV C C
8
0 10k
0 exp( )Ek kRT
3lbmole
ft
Reaction rate :
Where
VR: reactor volume
CA: concentration of Aniline
CH: concentration of Hydrogen
• Reaction kinetics :
Where
E : activity energy
T : temperature (R) 2000 BtuE
lbmole
3lbmole
ft
3ft
Reaction Kinetics Input
Reaction Kinetics Input
Reaction Kinetics Input
Feeds Conditions
1100 lbmolhr1400 lbmolhr
Two fresh feed stream :
Aniline feed Hydrogen feed
mole rate
temperature
pressure
100 F 100 F
650 psia 650 psia
Feeds Conditions
153
Check result
(1) Compare the conversion between RSTOIC and RCSTR.
(2) Compare the net duty inside the RSTOIC and RCSTR Question:
154
Introduction to Aspen Plus
Part 6: Running simulation
Distillation Process
(DSTWU, RADFRAC)
1
2
39
Saturated Feed
P=1.2atm
F=100 kmol/hr
zwater=0.5
zHAc=0.5
xwater=0.99
xHAc=0.99
40
20
Distillation Separation
• 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.
RR ?
QR ?
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
1
Saturated Feed
P=100 Kpa
F=100 kmol/hr
xben=0.4
xtol=0.6
xben=0.9
xben<0.1
n
From Overall Material Balance:
100 = D+B
From Benzene Balance:
100*0.4 = 0.9 * D+ 0.1* B
Thus, D=37.5 and B=62.5.
37.5
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)
RR=3 from the problem, distillate rate = 37.5
(kmol/h) from previous calculation
7 stages 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??)
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Introduction to Aspen Plus
Part 7: Running simulation
(Additional)
Design, spec, and vary in RADFRAC
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)
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Thanks for your attention!
PSE Laboratory Department of Chemical Engineering
Nation Taiwan University (綜合 room 402)