Introduction to Aspen Plus --2015

8/20/2019 Introduction to Aspen Plus --2015

1/215

Introduction to Aspen Plus

Speaker: Bor-Yih Yu(余柏毅)

Date: 2014/09/18

[email protected]

PSE Laboratory

Department of Chemical EngineeringNation Taiwan University

(綜合

room 402)

Edited by:程建凱

/吳義章

/余柏毅


2/215

2


Part 1: Introduction


3/215


4/215

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.

4Ref: http://www.aspentech.com/products/aspen-plus.cfm


5/215

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 5

http://www.aspentech.com/brochures/Aspen_Plus.pdfhttp://www.aspentech.com/brochures/Aspen_Plus.pdfhttp://www.aspentech.com/brochures/Aspen_Plus.pdf


6/215

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 6


7/215

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

7


8/215

Lesson Objectives

• Familiar with the interface of Aspen Plus

• Learn how to use properties analysis

• Learn how to setup a basic process simulation

8


9/215

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)

9


10/215


10

Part 2: Startup


11/215

Start with Aspen Plus

Aspen Plus User Interface


12/215

Aspen Plus Startup

12


13/215

Interface of Aspen Plus

Process Flowsheet Windows

Model Library (View| Model Library )

Stream

Help

SetupComponents

Properties

Streams

Blocks

Data Browser

Next

Check Result

StopReinitialize

Step

Start

Control Panel

Process Flowsheet Windows

Model Library (View| Model Library )

Status message13


14/215

More Information

Help for Commands for Controlling Simulations 14


15/215

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

15


16/215

Setup – Specification

Run Type

Input mode

16


17/215

Input components

Remark: If available, are

17


18/215

Properties

Process type(narrow the number of

methods available)

Base method: IDEAL, NRTL, UNIQAC, UNIFAC…

18


19/215

Property Method Selection—General Rule

19

Example 1:

water - benzene

Example 2:

benzene - toluene


20/215

Typical Activity Coefficient Models

Non-Randon-Two Liquid Model (NRTL)

Uniquac Model

Unifac Model


21/215

Typical Equation of States

Peng-Robinson (PR) EOS

Redlich-Kwong (RK) EOS

Haydon O’Conell (HOC) EOS


22/215

Thermodynamic Model – NRTL

NRTL

22


23/215

NRTL – Binary Parameters

Click “NRTL” and then built-in binary parameters

appear automatically if available.

23


24/215

Access Properties Models and

Parameters

24

Review Databank Data


25/215

Review Databank Data

Description of each parameter

Including:

Ideal gas heat of formation at 298.15 KIdeal gas Gibbs free energy of formation at

298.15 K

Heat of vaporization at TB

Normal boiling point

Standard liquid volume at 60°F….

25


26/215

Pure Component

Temperature-Dependent Properties

CPIGDP-1 ideal gas heat capacity

CPSDIP-1 Solid heat capacityDNLDIP-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

26


27/215

Example: PLXANT-1

(Extended Antoine Equation)

?

Corresponding Model

Click “ ?” and then click where you don’t know

27


28/215

Example: CPIGDP-1

(Ideal Gas Heat Capacity Equation)

?

Corresponding Model

28


29/215

Basic Input---Summary

• The minimum required inputs to run a simulation

are:

– Setup

– Components – Properties

– Streams

– Blocks

Property Analysis

Process Simulation

29


30/215

30


Part 3: Property analysis


31/215

Overview of Property AnalysisUse 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 ternarysystems

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

31

***When you start properties analysis, you MUST specify components ,

thermodynamic model and its corresponding parameters. (Refer to Part 2)


32/215

Find Components

32

Component ID : just for distinguishing in Aspen.Type : Conventional, Solid….etc

Component name : real component name

Formula : real component formula


33/215

Find Components

33

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)


34/215

Find Components

34

TIP 2: If you know the component name

(like N-butanol, Ethanol….etc), you can

enter it in “component name”.


35/215


36/215

Select Thermodynamic Model

36

Select NRTL


37/215

Check Binary Parameter

37

Click This, it will automatically change to

red if binary parameter exists.

Properties

Parameters

NRTL-1


38/215

Find Components

38

TIP 2: If you know the component name

(like N-butanol, Ethanol….etc), you can

enter it in “component name”.


39/215

Find Components

39

You can enter

the way of

searching…


40/215

Properties Analysis – Pure Component

40


41/215

Available Properties

Property (thermodynamic) Property (transport)

Availability Free energy Thermal conductivity

Constant pressure

heat capacityEnthalpy 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 correctionDensity

Enthalpy departure Entropy

Enthalpy departure

pressure correctionVolume

Enthalpy of

vaporizationSonic velocity

Entropy departure 41


42/215

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”

42


43/215

Example1: Calculation Results of CP

Data results 43


44/215

Properties Analysis – Binary Components


45/215

Binary Component Properties Analysis

Use this Analysis type To generate

TxyTemperature-compositions diagram at

constant pressure

Pxy Pressure-compositions diagram atconstant 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 phasesat a given temperature and pressure.


46/215

Example: T-XY

1. Select analysis type (Txy)

2. Select phase (VLE, VLLE)

2. Select two component

4. Specify composition range

5. Specify pressure


3. Select compositions basis



47/215

Example: calculation result of T-XY

Data results


48/215

Example: Generate XY plot

Click “plot wizard” to generate XY plot


49/215

Example: Generate XY plot (cont’d)

Properties Analysis – Ternary


50/215

Properties Analysis Ternary

(add one new components)



51/215

Properties Analysis Ternary

(Check NRTL binary parameter)

3 components -> 3 set of binary parameter

(How about 4 components??)


52/215



53/215

Ternary Map

4. Select phase (VLE, LLE)

1. Select three component

5. Specify pressure


2. Specify number of tie line


6. Specify temperature

(if LLE is slected)


54/215

Calculation Result of Ternary Map (LLE)

Data results


55/215

Property Analysis – Conceptual Design

Use this form To generate

PureTables 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

TernaryTernary maps showing phase envelope, tie lines, and azeotropes of ternary

systems

AzeotropeThis 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

55

(Optional)


56/215

Conceptual Design


57/215

Azeotrope Analysis


58/215

Azeotrope Analysis

4. Select phase (VLE, LLE)

1. Select components (at least two) 2. Specify pressure


5. Select report Unit

6. click Report to generate the results


59/215

Error Message

Close analysis input dialog box (pure or binary analysis)


60/215

Azeotrope Analysis Report


61/215

Ternary Maps


62/215

Ternary Maps

4. Select phase (VLE, LLE)1. Select three components

2. Specify pressure


5. Select report Unit

6. Specify temperature of LLE(If liquid-liquid envelope is selected)

6. Click Ternary Plot to generate the results


63/215

Ternary Maps

Ternary Plot Toolbar:

Add Tie line, Curve,

Marker…

Change pressure or

temperature


64/215

64


Part 4: Running simulation

Simple Units

(Mixer, Pump, valve, flash, heat exchanger)

Example 1: Calculate the mixing


65/215

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 ? ? ? ?65


66/215

Setup – Specification

Select Flowsheet

66


67/215

Reveal Model Library

View|| Model Libraryor press F10

67


68/215

Adding a Mixer

Click “one of icons”and then click again on the flowsheet window

Remark: The shape of the icons are meaningless

68


69/215

Adding Material Streams

Click “Materials” and then click

again on the flowsheet window

69


70/215


71/215

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)

71


72/215

Adding Material Streams (cont’d)

After selecting “Material Streams”, click and pull a stream line. Repeat it three times to generate three stream lines.

72

Reconnecting Material Streams


73/215


(Feed Stream)

Right Click on the stream and

select Reconnect Destination

73



74/215


(Product Stream)

Right Click on the stream and

select Reconnect Source

B1

1

2

3

74


75/215


76/215

Specifying Feed Condition (cont’d)

1 2

76


77/215

Specifying Input of Mixer

Right Click on the block and select Input

77


78/215

Specifying Input of Mixer (cont’d)

Specify Pressure and valid phase

78

l


79/215

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 calculationsStep Step through the flowsheet one block at a time

Stop Pause simulation calculations

Reinitialize Purge simulation results

79


80/215

S l


81/215

Stream Results

Right Click on the block and

select Stream Resu lts

81

1 2 3


82/215

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.

82

Enthalpy and Entropy

Ch U i f C l l i R l


83/215

Change Units of Calculation Results

83

S D fi i Y O U i S


84/215

Setup – Defining Your Own Units Set

84

S t R t O ti


85/215

Setup – Report Options

85

Stream Results with Format of


86/215

Mole Fraction

86

Add P Bl k


87/215

Add Pump Block

87

Add A M t i l St


88/215

Add A Material Stream

88


89/215

P S ifi ti


90/215

Pump – Specification

2. Specify pump outlet specificati(pressure, power)

1. Select “Pump” or “turbine”

3. Efficiencies (Default: 1)

90

R Si l ti


91/215

Run Simulation

Click to generate the results

Check “simulation status”

“Required Input Complete”

91

Block Results (Pump)


92/215

Block Results (Pump)

Right Click on the block and select Results

92


93/215

93


94/215

Calculation Results


95/215

(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 25Temperature 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

95


96/215

Example 2: Flash Separation


97/215

Example 2: Flash Separation

Saturated Feed

P=1atm

F=100 kmol/hr

zwater =0.5zHAc=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

( o C )

xWater

and yWater

T-x

T-y

Input Components


98/215

Input Components


99/215


100/215

Association parameters of HOC


101/215

Association parameters of HOC

Binary Parameters of NRTL


102/215

Binary Parameters of NRTL


103/215

T-xy plot


104/215

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 method3. Select compositions basis



105/215

Generate xy plot


106/215

Generate xy plot

Generate xy plot (cont’d)


107/215

Add Block: Flash2


108/215

Add Block: Flash2

Add Material Stream


109/215

Add Material Stream

Specify Feed Condition


110/215

Specify Feed Condition

Saturated Feed

(Vapor fraction=0)

P=1atm

F=100 kmol/hr

zwater =0.5

zHAc

=0.5

Block Input: Flash2


111/215

Block Input: Flash2

Flash2: Specification


112/215

Flash2: Specification

T=105 C

P=1atm

Required Input Complete


113/215

Required Input Complete

Click to run simulation

**Before running simulation, property

analysis should be closed.

Stream Results


114/215

Stream Results

Stream Results (cont’d)


115/215

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


116/215

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


117/215

117

Thermodynamic Model – NRTL


118/215

118

ADD BLOCK: HEATX


119/215

Feeds Conditions


120/215

Feeds Conditions

HOT-INCLD-IN

BLOCK INPUT


121/215

Check result


122/215

122

Check result

Check result


123/215

123


124/215

124



Reactor Systems

(RGIBBS, RPLUG,RCSTR)


125/215

Equilibrium Reactor: RGIBBS


126/215

126

q

222

2422

242

24

3

H COO H CO

O H CH H CO

O H CH H CO

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



127/215

127

q



128/215

q

Inside the Block:

Check result


129/215

129

KINETICS REACTORS: RPLUG


130/215


Reaction :Exothermic & reversible

222 H COO H CO )/(09.41 mol KJ H

)

85458

exp(1.3922

)47400

exp(545.51

)(222

RT k

RT k

skgcat

kmol Y Y k Y Y k Rate

r

f

H COr O H CO f

Rate [=] Kmol/Kgcat/s

Activation Energy [=] KJ/Kmol



131/215


Reaction :Exothermic & reversible

222 H COO H CO )/(09.41 mol KJ H

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 0.392CO2 0.148



132/215


Feed Stream:



133/215


Reaction Setting:



134/215


Reaction Setting:


135/215



136/215


RPLUG Setting:



137/215


RPLUG Setting:

Check result


138/215

138

Check result


139/215

139

Check result


140/215

140

Select Reactor Length column

Plot -> x-Axis variable

Select Temperature Column

Plot -> y-Axis variable

Display Plot

Check result


141/215

141

Block B2 (RPlug) Profiles Process Stream

Reactor length MIXED meter

T E M P E R A T U R

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

5 8 5 . 0

5 8 7 . 5

5 9 0 . 0

5 9 2 . 5

5 9 5 . 0 5

9 7 . 5

6 0 0 . 0

6 0 2 . 5

6 0 5 . 0

6 0 7 . 5

Temperature MIXED


142/215

Check result


143/215

143

Select Reactor Length column

Plot -> x-Axis variable

Select all other columns

Plot -> y-Axis variable

Display Plot

Check result


144/215

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 5

0 . 1

0 . 1 5

0 . 2

0 . 2 5

0 . 3

0 . 3 5

0 . 4

0 . 4

5

0 . 5

Mole fraction MIXED CO

Mole fraction MIXED H2OMole fraction MIXED CO2

Mole fraction MIXED H2

KINETICS REACTORS: RCSTR


145/215

Reaction :Exothermic & Irreversible

Aniline + Hydrogen Cyclohexylamine (CHA)

C6H7N + 3H2 C6H13N

Reactor Conditions


146/215

Reactor :

Reactor

condition

Reactor type

Reactor liquid level

595 psi

250 F

1200 ft3

Temperature

Volume

Vertical cylindrical vessel

80%

Pressure

Reactor Conditions Input


147/215

Reaction Kinetics


148/215

CHA R A H R kV C C

8

0 10k

0 exp( ) E k k RT

3lbmole ft

Reaction rate :

Where

VR: reactor volume

C A: concentration of AnilineCH: concentration of Hydrogen

• Reaction kinetics :

Where

E : activity energy

T : temperature (R)2000 Btu E

lbmole

3lbmole

ft

3 ft

Reaction Kinetics Input


149/215



150/215



151/215

Feeds Conditions


152/215

1

100 lbmolhr

1400 lbmolhr

Two fresh feed stream :

Aniline feed Hydrogen feed

mole rate

temperature

pressure

100 F 100 F

650 psia 650 psia


153/215

Check result


154/215

154

(1) Compare the conversion between RSTOIC and RCSTR.

(2) Compare the net duty inside the RSTOIC and RCSTRQuestion:


155/215

155



Distillation Process

(DSTWU, RADFRAC)

Distillation Separation


156/215

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

• There are two degrees offreedom to manipulate

distillate composition and

bottoms composition to

manipulate the distillate andbottoms 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 SeparationExample :


157/215

Example :

A mixture of benzene and toluene containing 40 mol% benzeneis 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


158/215

1

Saturated Feed

P=100 Kpa

F=100 kmol/hr

xben=0.4

xtol=0.6

xben=0.9

xben


159/215

From thermodynamic phase equilibrium, and the calculation of operating line:

We can get the number of theoretical plate to be 7.


160/215

2. By the shortcut method in Aspen Plus (DISTWU)(Select property method)


161/215

Select NRTL


162/215

2. By the shortcut method in Aspen Plus (DSTWU)


163/215

Add the unit “DSTWU”

The red arrows are the required material stream!



164/215

Connect the required material stream



165/215

“Feed1” Stream specification

2. By the shortcut method in Aspen Plus(Column Specification)


166/215

From the problem Assume no pressure drop

Inside the column


167/215


168/215

2. By the shortcut method in Aspen Plus(Column Specification)


169/215

Get results by varying the

number of stages. (Initial

Guess)



170/215

RUN THE SIMULATION

2. By the shortcut method in Aspen Plus(Stream Results)


171/215

Click right button on the unit, and select “Stream

Results”

2. By the shortcut method in Aspen Plus(Stream Results)


172/215

The required product

quality

2. By the shortcut method in Aspen Plus(RR vs number of stage)


173/215

For RR=3, at least 7

theoretical stages are

required.

3. More rigorous method in Aspen Plus (RADFRAC)


174/215

Add the unit “RADFRAC”

The red arrows are the required material stream!

3. More rigorous method in Aspen Plus (RADFRAC)


175/215

Connect the required material stream

3. More rigorous method in Aspen Plus (RADFRAC)(Feed Specification)


176/215

Same as Case 2

3. More rigorous method in Aspen Plus (RADFRAC)(Column Specification)


177/215

Double click left button on the unit….


178/215



179/215

Specify the feed stage.



180/215

Specify the pressure at the top of column

3. More rigorous method in Aspen Plus (RADFRAC)(Calculation of tray size—Tray Sizing)


181/215


182/215

3. More rigorous method in Aspen Plus (RADFRAC)(Pressure drop calculation – Tray Rating)


183/215



184/215

*Calculation from 2th tray from the top to

2th tray from the bottom. (WHY??)

*Initial guess of the tray size



185/215

3. More rigorous method in Aspen Plus (RADFRAC)(Stream Results)


186/215

Click right button on the unit, and select “Stream

Results”



187/215

Different from the shorcut method.

(WHY??)


188/215

188


Part 7: Running simulation(Additional)

Design, spec, and vary in RADFRAC

3. More rigorous method in Aspen Plus (RADFRAC)(Design , Spec and Vary)


189/215


190/215



191/215

What do we want??

--- 90% Benzene at top.

Select “Mole Purity”…

And the target is 0.9.


192/215


193/215



194/215

Add a Vary

(1 Design Spec 1 Vary)



195/215

Varying Reflux ratio to

reach the design target.


196/215



197/215

2nd Design Spec



198/215

What do we want??

--- 10% Benzene at bot.

Select “Mole Purity”…


199/215



200/215

Select the Benzene



201/215

Select the bottom stream



202/215

2nd Vary



203/215

Varying distillate rate to

reach the design target.

Specify the varying range.

(Should contain the initial value)



204/215

RUN THE SIMULATION,

and click right button on

the unit, select “Stream

results”



205/215

The required product

quality

3. More rigorous method in Aspen Plus (RADFRAC)(Column Results--top)


206/215

Calculated Reflux Ratio = 6.14

(from problem: 3)

3. More rigorous method in Aspen Plus (RADFRAC)(Column Results--bottom)


207/215

The required heat duty for

separation is 2341.8 (KW)

3. More rigorous method in Aspen Plus (RADFRAC)(Profile Inside the Column)


208/215

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)


209/215

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)


210/215

Select the column “Stage”

Click “Plot”

Select “X-axis variable”



211/215

Select the column “Temp.”

Click “Plot”

Select “ Y-axis variable”



212/215

Then, select “Display

Plot”



213/215

ExerciseExample:

Typically 90 mol% product purity is not enough for a product to


214/215

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)


215/215

Thanks for your attention!

PSE LaboratoryDepartment of Chemical Engineering

Nation Taiwan University(綜合 room 402)

Documents

Introduction to Aspen Plus --2015