AspenFlareSysAnalV7 3 Start

Getting Started Guide

Aspen Flare System Analyzer

Version Number: V7.3March 2011

Copyright (c) 1981-2011 by Aspen Technology, Inc. All rights reserved.

Aspen Flare System Analyzer, Aspen Flarenet, and the aspen leaf logo are trademarks or registeredtrademarks of Aspen Technology, Inc., Burlington, MA. All other brand and product names aretrademarks or registered trademarks of their respective companies.

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Contents i

Contents

1 Introduction.........................................................................................................1

About this document.........................................................................................1Audience.........................................................................................................1Related Documentation.....................................................................................1Technical Support ............................................................................................1

2 Building and Running a Model ..............................................................................3

Overview.........................................................................................................3Data Requirements...........................................................................................4

Pipe Segment Data.................................................................................4Relief Source Data..................................................................................5System Design Constraints......................................................................6

Starting Aspen Flare System Analyzer.................................................................6Starting a New Model........................................................................................7Saving the Model ........................................................................................... 11Building the Pipe Network ............................................................................... 11

Starting the Pipe Network ..................................................................... 11Completing the Pipe Network................................................................. 15

Defining the Scenarios .................................................................................... 25Defining the Sources ...................................................................................... 32Rating the Network ........................................................................................ 44Printing Data and Results ................................................................................ 47

3 Developing the Model.........................................................................................49

Overview....................................................................................................... 49Data Requirements......................................................................................... 50

Pipe Segment Data............................................................................... 50Relief Source Data................................................................................ 51System Design Constraints.................................................................... 53

Opening the Old Model.................................................................................... 53Updating the Model ........................................................................................ 54Defining the Scenarios .................................................................................... 63Defining the Sources ...................................................................................... 67

Sizing the Network ............................................................................... 75Design Calculations ........................................................................................ 78

1 Introduction 1

1 Introduction

This section provides information on the following topics:

About this Document

Audience

Related Documentation

Technical Support

About this documentThe guide provides step by step instructions to the most commonly usedfeatures within Aspen Flare System Analyzer (previously named AspenFlarenet).

AudienceThis guide is intended for process and process systems engineers.

Related Documentation

Title Content

Aspen Flare System AnalyzerReference Manual

Reference Manual for Using AspenFlare System Analyzer

Technical SupportAspenTech customers with a valid license and software maintenanceagreement can register to access the online AspenTech Support Center at:

http://support.aspentech.com

This Web support site allows you to:

Access current product documentation

http://support.aspentech.com/

2 1 Introduction

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Registered users can also subscribe to our Technical Support e-Bulletins.These e-Bulletins are used to alert users to important technical supportinformation such as:

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Customer support is also available by phone, fax, and email. The most up-to-date contact information is available at the AspenTech Support Center athttp://support.aspentech.com.

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2 Building and Running a Model 3

2 Building and Running aModel


Overview

Data Requirements

Starting Aspen Flare System Analyzer

Starting a New Model

Saving the Model

Building the Pipe Network

Defining the Scenario

Defining the Sources

OverviewThis Getting Started tutorial shows the fundamental principles involved inusing Aspen Flare System Analyzer to design and rate a new flare system.This guided tour will expose you to most of the major features of Aspen FlareSystem Analyzer.

This tutorial assumes that you are familiar with the use of Microsoft Windowsand have some prior experience in the design of flare systems.

This example consists of the following main parts:

1 Building The Pipe Network - Pipes and nodes will be added using eitherthe Process Flowsheet or Pipe Manager.

2 Defining the Scenarios - Different scenarios will be set up to simulatevarious process conditions.

3 Defining The Sources - Relieving sources will be added to each scenario.

4 Sizing the Network - Finally, the pipe network will be simulated andresults will be viewed both in textual and graphical form.

4

Data RequirementsBefore you can start to build a computer model of the flare header system,you must first define all the data that will determine your system.

When you are sizing a flare system, the initial pipe diameters may affect thesolution when there is a liquid phase and thmodeled. You should initially size a net

Pipe Segment Data

Data

Connectivity

Length and fittingsloss coefficients foreach pipe segment

Diameter and pipeschedule for eachpipe segment

The following diagram shows the connectivity of the system that you will bedesigning in this example.

Fig 2.1

2 Building and Running a Model

Data Requirementsu can start to build a computer model of the flare header system,

you must first define all the data that will determine your system.

When you are sizing a flare system, the initial pipe diameters may affect thesolution when there is a liquid phase and the liquid knockout drum ismodeled. You should initially size a network using vapor phase methods.

Pipe Segment Data

Description

You would normally have prepared a system sketch thatdefines the nodes to which the pipe segments are conne

Length and fittingsloss coefficients foreach pipe segment

These will be based upon either a preliminary or detailedisometric drawing of the piping.

Diameter and pipeschedule for each

If you are rating an existing network, these wtaken from the flare system P&ID. If you are sizing a newflare system, the pipe diameters that you define are relativelyunimportant since they will be overwritten by the sizingalgorithms. It is recommended that reasonable diameters bedefined, so that the sizing algorithm initializes to a conditionthat will give faster convergence.

The following diagram shows the connectivity of the system that you will bedesigning in this example.


u can start to build a computer model of the flare header system,you must first define all the data that will determine your system.

When you are sizing a flare system, the initial pipe diameters may affect thee liquid knockout drum is

work using vapor phase methods.

You would normally have prepared a system sketch thatdefines the nodes to which the pipe segments are connected.

These will be based upon either a preliminary or detailed

If you are rating an existing network, these will normally betaken from the flare system P&ID. If you are sizing a newflare system, the pipe diameters that you define are relativelyunimportant since they will be overwritten by the sizingalgorithms. It is recommended that reasonable diameters be

fined, so that the sizing algorithm initializes to a condition

The following diagram shows the connectivity of the system that you will be


The piping in the network diagram is detailed in the following table:

Item Length(m)

InternalDiameter(mm)

WallThickness(mm)

FittingsLoss

ElevationChange(m)

Flare Tip 3.0 0

Stack 100 876.3 19.05 0 100

Header 3 50 876.3 19.05 0 0

Tail Pipe 1 25 428.65 14.275 0 0

Tail Pipe 2 25 428.65 14.275 0 0

The flare tip is not a pipe segment, but rather a node that represents a zerolength piece of pipe with defined fittings loss coefficients. Since the internaldiameter is not specified, it will assume the same diameter as the upstreampipe segment. Fittings loss coefficients for the flare tip exclude pipeenlargement and junction losses for the connection to the upstream pipewhich will automatically be calculated.

Relief Source DataThe following data must be specified for the sources:

Data Description

Flow andComposition

These may vary for each scenario that you are evaluating. If arelief source is not used in a particular scenario, the flow maybe set to zero. Flow refers to the quantity of fluid that thesource valve must pass as a consequence of the plant upsetcondition. Rated Flow refers to the quantity of fluid that thesource valve will pass due to its physical construction. RatedFlow must always be greater than or equal to Flow.

Maximum AllowableBack Pressure(MABP)

This is the maximum pressure that can exist at the outlet ofthe device (source) without affecting its capacity.

Downstreamtemperature

This temperature is used as the pressure independenttemperature at which the source enters the network. Thistemperature is used when ideal gas enthalpies are used tocalculate the heat balance, or as an initial guess when anyother enthalpy method is used.

Upstream pressureand temperature

These are only used if Ideal Gas enthalpies are not used forthe heat balance. These may vary for each scenario that youare evaluating. With relief valves, the flowing pressure shouldbe used.

Discharge flangesize

This will normally be determined from the relief valve sizingcalculations. If this value is unknown then the field should beleft empty to ignore the pressure change from the valve tothe downstream pipe due to the swage.

In this example, you will consider three scenarios that represent one fire caseand two single blocked discharge cases. The following tables define the sourcedata for each scenario.

Default Source Data

6 2 Building and Running a Model

SourceName

Flowrate(kg/hr)

FlangeSize(mm)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 100000 300 20 15 15 10 5.0

Source 2 100000 300 25 15 15 10 5.0

Source 1 is a control valve while Source 2 is a relief valve.

Source 1 Only Data

SourceName

Flowrate(kg/hr)

FlangeSize(mm)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 100000 300 20 15 15 10 5.0

Source 2 0 300 25 15 15 10 5.0

Source 2 Only Data

SourceName

Flowrate(kg/hr)

FlangeSize(mm)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 0 300 20 15 15 10 5.0

Source 2 100000 300 25 15 15 10 5.0

System Design ConstraintsIn this case, the following data is used for both scenarios:

Maximum allowable mach number - 0.50 for both main headers andtailpipes.

Maximum allowable noise – 100 dB for both main headers and tailpipes.

Starting Aspen Flare SystemAnalyzerThe installation process creates a short-cut to Aspen Flare System Analyzer inthe Start menu.

To Start Aspen Flare System Analyzer:

1 Select the Start menu.

2 Navigate to and click the Aspen Flare System Analyzer icon underPrograms | AspenTech | Process Modeling <version>

Now you are ready to begin working with Aspen Flare System Analyzer.

When you start Aspen Flare System Analyzer, the Aspen Flare SystemAnalyzer application window appears. Before setting up the Getting Startedcase, you should choose the Aspen Flare System Analyzer units set fordisplaying information. You can check your current units set by accessing thePreferences Editor:


1 Click the aspenONE Buttonapplication windowThe Preferences Editor

2 The current unit set is shown in theMetric, which will be used for this exam

3 Confirm that thewill open the object editor view each time a new object is added.

4 Click OK to close the

Starting a New ModelTo start a new case, do one of the following:

1 Click New on theclick the aspenONE Button, then clickThe Documentation Editor

2 Enter the appropriate data into theDescription

The Component Manager

Click the aspenONE Button which is on the upper left corner of theapplication window; then select Preferences from the Application Menu.

Preferences Editor is displayed.

The current unit set is shown in the Units box. The default, which will be used for this example.

Confirm that the Edit Objects on Add check box is selectedwill open the object editor view each time a new object is added.

to close the Preferences Editor.

arting a New ModelTo start a new case, do one of the following:

on the Quick Access Toolbar beside the aspenONE Button; or,click the aspenONE Button, then click New from the Application Menu.

Documentation Editor is displayed.

appropriate data into the User Name, Job Codefields, and then click OK.

Component Manager is displayed.

7

which is on the upper left corner of thefrom the Application Menu.

. The default unit set is

selected. This optionwill open the object editor view each time a new object is added.

Quick Access Toolbar beside the aspenONE Button; or,from the Application Menu.

Job Code, Project, and

8

Fig 2.2

Note: The Selectedhave yet been installed in the case.

There are a number of ways to select components for your simulation. Onemethod is to filter the database for a certain component type. In this model,we will be using the following components:

To add Methane

1 Ensure that the

2 Typing methanetyping, the Availablethe matching components.

3 Double-click Methanenow be selected and shown in the

Note: Initially, all the checkselected. You can


Selected component list is empty, indicating that no componentshave yet been installed in the case.

number of ways to select components for your simulation. Onemethod is to filter the database for a certain component type. In this model,we will be using the following components: Methane, Ethane

Methane using the filter option:

Ensure that the HC check box in the Component types group is

methane in the Selection filter field. Notice that as you areAvailable components list will be filtered out to show only

the matching components.

Methane in the Available components list.now be selected and shown in the Selected components

Initially, all the check boxes in the Component types group are. You can clear them by clicking Invert.


list is empty, indicating that no components

number of ways to select components for your simulation. Onemethod is to filter the database for a certain component type. In this model,

Ethane and Propane.

group is selected.

field. Notice that as you arest will be filtered out to show only

list. Methane willlist.

group are


Fig 2.3

4 Repeat the previous step withmethod, you may scroll through thesee the desired component. Highlight the component by clicking itthen click Add

Note: Notice that now all the required components are shown in theSelected componentscase.

The Component Manager

Repeat the previous step with Ethane and Propane. As an alternativemethod, you may scroll through the Available componentssee the desired component. Highlight the component by clicking it

Add to place it in the Selected components list.

Notice that now all the required components are shown in theomponents list, indicating that they have been installed in the

Component Manager will now appear as follows:

9

. As an alternativeAvailable components list until you

see the desired component. Highlight the component by clicking it, andlist.

Notice that now all the required components are shown in theey have been installed in the

10

Fig 2.4

5 Click OK to close thecomponents.

6 In the Navigation Pane,select Componentsdisplayed:

Fig 2.5


to close the Component Manager and accept the list of

In the Navigation Pane, double-click Inputs on the Viewsmponents from the list. The Components data view will be

uilding and Running a Model

and accept the list of

pane, and thendata view will be


Note: You can use the horizontal scroll bar at the bottom of the sheet to viewall of the component properties.

Saving the ModelIt is good practice to periodically save your case by doing one of thefollowing:

Click the Save icon on the Quick Access Toolbar.

Click the aspenONE Button on the upper left corner of the applicationwindow, and then select Save from the Application Menu.

Press Ctrl+S.

As this is the first time you have saved your case, the All Files dialog box willbe displayed.

After selecting an appropriate disk drive and directory in the Save in list,enter the name of the file to which you want to save the case in the Filename field.

Note: You do not need to include the .fnwx extension; Aspen Flare SystemAnalyzer will add it automatically.

Click Save to close the dialog box and save the file.

Building the Pipe NetworkSince all scenarios have a common pipe network, you should first build thepipe network model via the Process Flowsheet.

Starting the Pipe Network1 Click Process Flowsheet in Views group on the Home tab of the

Ribbon. The Process Flowsheet will be displayed, and the ProcessFlowsheet tab will be shown on the Ribbon.

Note: Before proceeding any further, make sure that the Edit Objects onAdd check box on the General tab of the Preferences Editor is selected.

12

Fig 2.6

At this point the flowsheetobject yet.

The desired objects can be added by using either of the following methods:

Clicking the PalettePalette, which displays all the objects available inAnalyzer. You can add an object byFlowsheet.

Fig 2.7


flowsheet should be blank, since we have not added a single

objects can be added by using either of the following methods:

Palette on the Process Flowsheet tab will open the, which displays all the objects available in Aspen Flare System. You can add an object by dragging it onto the Process


should be blank, since we have not added a single

objects can be added by using either of the following methods:

will open theAspen Flare System

Process


Objects can also be added via theManager. These are accessible throughgroup on the

For example, to add a pipe:

2 Click the pipe icon in thethe Process Flowsheet.the Name field.

3 Next, add a Flare TipProcess FlowsheetThe Flare Tip Editorthe flowsheet

Fig 2.8

By default the Flare Tipto a more appropriate name as follows:

4 Click in the Name

5 Delete the default name an

Since this example is of smaller size, theThis field is only useful for larger cases with multiple sections (areas)within a same plant. Now you need to specify the pipe, which will besimulated as a flare stack

6 Select Stack

7 In the At fieldFlare Tip.

Objects can also be added via the Pipe Manager and the. These are accessible through Pipes and Nodes

group on the Home tab of the Ribbon, respectively.

, to add a pipe:

Click the pipe icon in the Palette, drag and drop it to a proper place onthe Process Flowsheet. In the Pipe Editor that is displayed, type

field. Click OK to close the Pipe Editor.

Flare Tip. Drag the Flare Tip icon on the PaletteProcess Flowsheet. Since the Edit Objects on Add check box is selected,

Flare Tip Editor will be displayed after the Flare Tip is installed tolowsheet:

By default the Flare Tip has been named as FlareTip1, which can be changedto a more appropriate name as follows:

Name field on the Connections tab of the Flare Tip Editor

Delete the default name and type Flare Tip as the new name.

Since this example is of smaller size, the Location field will be left blank.This field is only useful for larger cases with multiple sections (areas)within a same plant. Now you need to specify the pipe, which will beimulated as a flare stack, and it is attached to the Flare Tip

from the list in the Upstream node field.

field, select Downstream as the pipe end connected to the

13

NodeNodes in the Build

, drag and drop it to a proper place onthat is displayed, type Stack in

Palette to thebox is selected,

the Flare Tip is installed to

, which can be changed

Flare Tip Editor.

as the new name.

field will be left blank.This field is only useful for larger cases with multiple sections (areas)within a same plant. Now you need to specify the pipe, which will be

Flare Tip.

as the pipe end connected to the

14

In order to completespecify the Diametertab.

Note: The Fitting Loss Coefficient Basisto indicate that the loss coeffloss in the Flare T

8 On the Calculationsloss in the appropriate fields.

Fig 2.9

Now you have provided all the necessary information about the

9 Click OK to close the view.

Notice that nowFlowsheet. These may be drawn one on top of the othermanually arrange them by clicking and dragging the object icons.

10 Open the Stackflowsheet and move to the

11 Specify the Length

This will result in a vertical pipe measuring 100 m tall.

12 Select the Nominal Diameter


In order to complete the input on the Flare Tip Editor, you need toDiameter and the Fitting Loss values on the Calculations

Fitting Loss Coefficient Basis should be set to Total Pressureto indicate that the loss coefficient we are defining will calculate the pressure

Tip including the velocity pressure loss.

Calculations tab, enter 876.3 as the diameter andloss in the appropriate fields.

Now you have provided all the necessary information about the

to close the view.

now two new objects have been added to the P. These may be drawn one on top of the other so you should

manually arrange them by clicking and dragging the object icons.

Stack Object Editor by double-clicking the pipe icon on theand move to the Dimensions tab.

Length as 100 m and the Elevation Change

This will result in a vertical pipe measuring 100 m tall.

Nominal Diameter as 36 inch and the Pipe Schedule


, you need toCalculations

Total Pressureicient we are defining will calculate the pressure

as the diameter and 3 as the fitting

Now you have provided all the necessary information about the Flare Tip.

two new objects have been added to the Processso you should

manually arrange them by clicking and dragging the object icons.

clicking the pipe icon on the

as 100 m.

Pipe Schedule as 40.


Fig 2.10

13 On the Methodsas Model Default

In this example, every pipe segment uses the default models which arespecified on the


Now you need to add another pipe segment which will be added using thePipe Manager

Completing the Pipe Network1 Click Pipes in

Manager will be displayed.

Methods tab, confirm that Vertical Pipe and VLE MethodModel Default.

In this example, every pipe segment uses the default models which arespecified on the Methods tab of the Calculation Options Editor

to close the Stack Object Editor.

Now you need to add another pipe segment which will be added using thePipe Manager.

Completing the Pipe Networkin the Build group on the Home tab of the Ribbon

will be displayed.

15

VLE Method are set

In this example, every pipe segment uses the default models which areCalculation Options Editor.

Now you need to add another pipe segment which will be added using the

tab of the Ribbon. The Pipe

16

Fig 2.11

2 Click Add.

A new pipe will be added to the list. Click

The Pipe Editor


will be added to the list. Click Edit.

Pipe Editor will be displayed.



Fig 2.12

3 Change the na

4 Move to the Dimensionsappropriate fields:

Field

Length (m)

Nominal Diameter (inch)

Pipe Schedule

5 Click OK to clo

6 Close the Pipe Manager

You need to attachSystem Analyzeryou need a simple connecwill be used.

7 On the PaletteFlowsheet.

This will open the

Change the name to Header 3.

Dimensions tab and enter the following data in theappropriate fields:

Value

50

Nominal Diameter (inch) 36

Pipe Schedule 40

to close the Pipe Editor.

Pipe Manager by clicking Close.

You need to attach Header 3 with Stack using a node. Aspen FlareSystem Analyzer allows you to choose between a variety of nodes, sinceyou need a simple connection between the two pipes, a Connector

Palette, click the Connector icon and drag it to the Process

This will open the Connector Editor.

17

tab and enter the following data in the

Aspen Flareallows you to choose between a variety of nodes, since

Connector node

and drag it to the Process

18

Fig 2.13

8 On the Connections

9 In the Downstreamat Upstream

10 In the Upstreamat Downstream

11 Move to the Calculations


Connections tab, enter the new name as Con 1.

Downstream node field, select Stack and specify the connectionUpstream (of Stack) in the At field.

Upstream node field, select Header 3 and specify the connectionDownstream (of Header 3) in the At field.

Calculations tab.


and specify the connection

and specify the connection


Fig 2.14

Notice that by default theloss methodleft at their default values for this example.


Now, a tee will be added, using thefrom the two

13 Click Nodes in theNode Manager

Notice that by default the Angle has a value of 90 deg and theethod is set as Calculated. These and the other entries may be

left at their default values for this example.

to close the Connector Editor.

Now, a tee will be added, using the Node Manager, to combine the flowfrom the two sources.

in the Build group on the Home tab of the RibbonNode Manager will be displayed.

19

deg and the Fitting. These and the other entries may be

, to combine the flow

tab of the Ribbon. The

20

Fig 2.15

14 Click Add and Select

Click Edit.

The Tee Editor


and Select Tee from the list. A new Tee will be added.

Tee Editor will be displayed.


A new Tee will be added.


Fig 2.16

15 Change the name to

16 Specify the DownstreamUpstream from the

17 Move to the Calculationssetting is Miller

18 Close the Tee Editor

19 Click Close to close the

Now, you can add two pipe segments to the upstream and branch sectionof Tee 1 using the

20 Open the Pipe Manager

Change the name to Tee 1 in the Name field.

Downstream node connection to be Header 3from the At field.

Calculations tab and verify that the Fitting lMiller. The remaining fields may be left at their default values.

Tee Editor by clicking OK.

to close the Node Manager.

Now, you can add two pipe segments to the upstream and branch sectionusing the Pipe Manager.

Pipe Manager by clicking Pipes in the Build group

21

Header 3 and select

oss methods. The remaining fields may be left at their default values.

Now, you can add two pipe segments to the upstream and branch section

group.

22

Fig 2.17

21 Click Add to add a new pipe segment.

22 Change the default pipe name to

23 Specify Tee 1in the At field

Note: Setting the tailpipe option tocalculated using the rated flows rather than the actual flow. For this pipewhich is a tail pipe twill be the same so the setting of this option will have no effect.


to add a new pipe segment. Click Edit to open the

Change the default pipe name to Tail Pipe 1.

Tee 1 as the Downstream node connection and selectfield.

Setting the tailpipe option to Yes will cause the pressure drop to becalculated using the rated flows rather than the actual flow. For this pipewhich is a tail pipe to a control valve source, the rated flow and actual flowwill be the same so the setting of this option will have no effect.


to open the Pipe Editor.

connection and select Branch

will cause the pressure drop to becalculated using the rated flows rather than the actual flow. For this pipe

o a control valve source, the rated flow and actual flowwill be the same so the setting of this option will have no effect.


Fig 2.18

24 Move to the Dimensions

25 Set Nominal Diameter

26 Click OK to close theanother pipe segment.

27 Change the new pipe segment name to

28 Specify Tee 1Upstream in theset the Tailpipe



Dimensions tab and specify the Length as 25

Nominal Diameter as 18 inch from the list.

close the Pipe Editor for Tail Pipe 1. Repeat Step 2another pipe segment.

Change the new pipe segment name to Tail Pipe 2.

Tee 1 as the Downstream node connection and selectin the At field. Since this pipe is a tail pipe for a relief valve

Tailpipe option to Yes.


Nominal Diameter as 18 inch from the list.

23

25 m.

. Repeat Step 21 to add

connection and select. Since this pipe is a tail pipe for a relief valve,

25 m.

24

Fig 2.19



In the Navigation Pane area which is dockedFlowsheet, select

The Pipes data sheet

Fig 2.20




In the Navigation Pane area which is docked to the left side of the Processelect Inputs | Pipes on the Views pane.

data sheet displays the data for all of the pipe segments:


the left side of the Process

displays the data for all of the pipe segments:


You could also check the Pconnections have been made. A portion of the Pbelow:

Fig 2.21

Defining the ScenariosYou now need to define the data for the entire scenario, theScenario, Source 1 Onlymust contain at least one scenario, a set of default scenario data is createdwhen you start a new case. We need to modify this data.

1 Click Scenarios

The Scenario Manager

ld also check the Process Flowsheet to ensure that the properconnections have been made. A portion of the Process Flowsheet

Defining the ScenariosYou now need to define the data for the entire scenario, the Default

Source 1 Only and Source 2 Only scenarios. Since each casemust contain at least one scenario, a set of default scenario data is createdwhen you start a new case. We need to modify this data.

Scenarios in the Build group on the Home tab of the Ribbon

Scenario Manager will be displayed.

25

to ensure that the properlowsheet is displayed

Defaultscenarios. Since each case

must contain at least one scenario, a set of default scenario data is created

tab of the Ribbon.

26

Fig 2.22

2 Double-click Default Scenario


Default Scenario in the Scenarios list.



Fig 2.23

3 The Scenario EditorDefault Scenario

Update the headerDefault ScenarioEditor and return

Scenario Editor will be displayed. Alternatively, you could selectDefault Scenario in the Scenarios list, and then click Edit

Update the header Mach Number limit on the ConstraintsDefault Scenario as shown below, then click OK to close the

and return to the Scenario Manager.

27

isplayed. Alternatively, you could selectEdit.

Constraints tab for theto close the Scenario

28

Fig 2.24

Now we should add the data for the

4 Make sure thatthe Scenario Managerlist as shown below.


Now we should add the data for the Source 1 Only scenario.

Make sure that Default Scenario is highlighted in the ScenariosScenario Manager. Click Clone. A new scenario will be added to the

list as shown below.


scenario.

Scenarios list onbe added to the


Fig 2.25

5 Click Edit to open the

6 Change the default name toSource 1 Only

to open the Scenario Editor for the new scenario

Change the default name to Source 1 Only and verify the data for theOnly scenario is the same as shown below.

29

for the new scenario.

the data for the

30

Fig 2.26

7 Click OK to close theto add a new scenario.

8 Change the name for the new scenario to


to close the Scenario Editor for Source 1 Only. Repeat Step 4o add a new scenario.

Change the name for the new scenario to Source 2 Only.


. Repeat Step 4


Fig 2.27

9 Verify the dataas shown below

the data for the new scenario on the Constraints tab is the samebelow.

31

tab is the same

32

Fig 2.28

10 Click OK to close theManager, then click

Defining the SourcesYou will now enter the source data for the sources in all scenarios. Since forthe first part of the example you will be defining the source compositions interms of molecularthe compositions on this basis.

1 Click the aspenONE Button at the upper left corner of the applicationwindow. SelectThe Preferences Editor


to close the Scenario Editor and return to the Scenari, then click Close to close the Scenario Manager

Defining the SourcesYou will now enter the source data for the sources in all scenarios. Since forthe first part of the example you will be defining the source compositions interms of molecular weight, the program preferences must be set to acceptthe compositions on this basis.

Click the aspenONE Button at the upper left corner of the applicationSelect Preferences from the Application Menu that is d

Preferences Editor will be displayed.


ScenarioScenario Manager.

You will now enter the source data for the sources in all scenarios. Since forthe first part of the example you will be defining the source compositions in

weight, the program preferences must be set to accept

Click the aspenONE Button at the upper left corner of the applicationthat is displayed.


Fig 2.29

Ensure that Molfield on the Defaults

Molecular Weight is selected in the Composition BasisDefaults tab.

33

Composition Basis

34

Fig 2.30


Before defining a set of source data, you must select the scenario whichcorresponds to this data. You will start by defining the data for theDefault Scenario

3 Make sure thatHome tab of thethis scenario. This

You can now add the data corresponding to this scenario for each source.

4 Click Nodes in


to close the Preferences Editor.

ng a set of source data, you must select the scenario whichcorresponds to this data. You will start by defining the data for theDefault Scenario.

Make sure that the Default Scenario is selected in the Runtab of the Ribbon. Any open data views would now display data for

this scenario. This field is regarded as the Scenario Selector


in the Build group. The Node Manager will be displayed:


ng a set of source data, you must select the scenario whichcorresponds to this data. You will start by defining the data for the

Run group on the. Any open data views would now display data for

Scenario Selector.


will be displayed:


Fig 2.31

5 Click Add and selectand select Control Valve from the list that is displayed

35

that is displayed.


Fig 2.32

Click Edit. The Control Valve Editor will be displayed:


Fig 2.33

6 Change the name toset connection to be atChange the name to Source 1. Select Tail Pipe 1 in the Outletset connection to be at Upstream (of Tail Pipe 1).

37

Outlet field and

38

Fig 2.34

7 Move to the Conditionsthis example, the inlet pressure and temperature are the same as thedefault values


Conditions tab and set the Mass Flow as 100000this example, the inlet pressure and temperature are the same as thedefault values, but this will not normally be the case.


100000 kg/hr. Inthis example, the inlet pressure and temperature are the same as the


Fig 2.35

8 On the Compositionentered the Mcomposition will be calculated to give the required

Composition tab, specify the Mol. Wt. to be 20. Once you haveMol. Wt. and tabbed to the next field, you will notice the

composition will be calculated to give the required Mol. Wt.

39

. Once you haveyou will notice theMol. Wt.

40

Fig 2.36

Note: The Mole FractionsWeight. Becausewill be used to match the

9 Click OK to close thethe Node Managerbe displayed.

10 Select Relief ValveValve Editor

11 Name the new source as

12 Select Tail Pipe 2Upstream (of


Mole Fractions are automatically estimated from the MolecularWeight. Because HC is selected from the list, only hydrocarbon componentswill be used to match the Molecular Weight.

to close the Control Valve Editor for Source 1. ClickNode Manager to add a new source. The node selection list will again

Relief Valve from the list, and then click Edit to openValve Editor.

Name the new source as Source 2 on the Connections tab.

Tail Pipe 2 in the Outlet field and set connection to be at(of Tail Pipe 2).


are automatically estimated from the Molecularrocarbon components

. Click Add into add a new source. The node selection list will again

to open the Relief

tab.

and set connection to be at


Fig 2.37

13 On the Conditionsis set to the default value ofthe Auto checkFlare System Analyzerand the selectedcase. Check that the relieving pressure is calculated as

14 Still on the Conditionsset to 5.0 bar.100000 kg/ hr. Select tThis tells Aspen Flare System Analyzervalve from the specified fluid conditions and properties, valve type andorifice area.

Conditions tab, check that the relief valve set pressure oris set to the default value of 10 bar which is correct for this source. Select

check box next to the Relieving Pressure field. This tellsFlare System Analyzer to calculate the relieving pressure from theand the selected Contingency, which should be left as Operating

k that the relieving pressure is calculated as 10.89

Conditions tab, check that the Allowable Backpressurebar. Enter the required Mass Flow rate for this source of

kg/ hr. Select the Auto check box next to the RatedAspen Flare System Analyzer to calculate the rated flow for the

valve from the specified fluid conditions and properties, valve type and

41

tab, check that the relief valve set pressure or MAWPect for this source. Select

field. This tells Aspento calculate the relieving pressure from the MAWP

Operating in this10.89 bar.

Allowable Backpressure israte for this source of

Rated flow field.to calculate the rated flow for the

valve from the specified fluid conditions and properties, valve type and

42

15 Still on the ConditionsValve field to select orifice codeupdated to 16774reflect the increased orifice area.

16 On the CompositionWhen you tab away from this field,calculate the composition of the fluid from the mole weight. Click back onthe Conditionsupdated to give a rated flow of

Fig 2.38


The Node Manager


Conditions tab, click the box next to the Orifice Area Perfield to select orifice code api_T. Check that the orifice area is

16774 mm2 and notice the rated flow calculation is updated toreflect the increased orifice area.

Composition tab, specify the Mol. Wt. of the fluid to beWhen you tab away from this field, Aspen Flare System Analyzercalculate the composition of the fluid from the mole weight. Click back on

Conditions tab to confirm that the Rated flow calculation has beenupdated to give a rated flow of 108,214 kg/hr.

to close the Relief Valve Editor.

Node Manager will now appear as follows:


Orifice Area Per. Check that the orifice area is

and notice the rated flow calculation is updated to

of the fluid to be 25.Aspen Flare System Analyzer will

calculate the composition of the fluid from the mole weight. Click back oncalculation has been


Fig 2.39

18 Close the Node Manager

19 In the Navigation Pane area which is dockedFlowsheet, select

The Sources data

Fig 2.40

You must now add the source data for the other two scenarios.

20 Select the Source 1 OnlyRun group on thedisplay data for this scenario.

21 Make the following changes to the flowratesin the Source 1 Only

Source 1 - Mass F

Node Manager by clicking Close.

In the Navigation Pane area which is docked to the left of the ProcessFlowsheet, select Inputs | Sources on the Views pane.

data sheet for the Default Scenario will be displayed:


Source 1 Only scenario from the Scenario Selectoron the Home tab of the Ribbon. Any open data views will now

display data for this scenario.

Make the following changes to the flowrates from the SourcesSource 1 Only scenario (all other information remains the same):

Mass Flow 100000 kg/hr, Mol. Wt. 20

43

the left of the Process

will be displayed:


Scenario Selector list in theny open data views will now

Sources data sheetcenario (all other information remains the same):


Source 2 - Mass Flow 0 kg/hr, Mol. Wt. 25

Finally reselect the Default Scenario from the Scenario Selector.

22 Next, select the Source 2 Only scenario from the Scenario Selector listin the Run group on the Home tab of the Ribbon. Make the followingchanges to the Source 2 Only:



Finally reselect the Default Scenario from the Scenario Selector.

Rating the NetworkWe have now entered all the model data and can now make the sizingcalculations. We will need to set the calculation options before starting thecalculations.

1 Click Options in the Run group on the Home tab of the Ribbon. TheCalculation Options Editor will be displayed:


Fig 2.41

2 For this exampledefined whenincludes the fol

On the GeneralHeat Transfercheck box should be cleared.

On the Scenarios

For this example, we are going to use the default methods and settingsdefined when Aspen Flare System Analyzer creates a new model. Thisincludes the following key options:

General tab, Calculation Mode should be set to Ratingeat Transfer check box should be cleared, Include Kinetic Energy

box should be cleared.

Scenarios tab, Calculate should be selected for All Scenarios

45

we are going to use the default methods and settingscreates a new model. This

Rating, EnableInclude Kinetic Energy

All Scenarios.

46

On the MethodsGas, the Enthalpy Methodto Isothermal Gas

Click OK to close the

You can now start the calculations.

3 Click Run in the

Fig 2.42

Once the calculations are complete you can review the results.

4 Select Results

The Messages data vi

Fig 2.43

The above view contains general information and warning messagesregarding the calculations.

5 Select Source 1 OnlyHome tab.

6 Select Results

The Pressure/Flow Summary


Methods tab, the VLE Method should be set to CompressibleEnthalpy Method to Ideal Gas and all pressure drop methods

Isothermal Gas.

to close the Calculation Options Editor.


in the Run group on the Home tab.


Results | Messages from the Views tab on the Navigation Pane

The Messages data view will be displayed.

The above view contains general information and warning messagesregarding the calculations.

Source 1 Only from the Scenario selector in the Run

Results | Pressure/Flow Summary from the Navigation Pane

Pressure/Flow Summary will be displayed:


Compressibleand all pressure drop methods


Navigation Pane.

The above view contains general information and warning messages

Run group on the

Navigation Pane.


Fig 2.44

With the Pressure/Flow Summaryusing the Scenario Selector

Note: In the scenarioPipe 1 is automatically highlighted.

7 At this point,Access Toolbarthe application window then select

Printing Data and ResultsTo print data and results:

1 Click the aspenONE Button, and then sMenu. The Print

2 Select the appropriate checkAlso select thescenarios instead of jusclick Text, thenbox.

3 Click Previewanything is pr

Pressure/Flow Summary sheet open, select each scenario in turnScenario Selector in the Run group.

In the scenario Source 1 Only, the mach number problem onis automatically highlighted.

save the model using either the Save icon onToolbar, or click the aspenONE Button at the upper left corner of

the application window then select Save from the Application M

Printing Data and ResultsTo print data and results:

Click the aspenONE Button, and then select Print from thePrint dialog box will be displayed.

the appropriate check boxes for the items that you want to print.the All Scenarios check box to print the results for all of the

scenarios instead of just the current scenario. If you want to print to a file,, then specify the file location and File name in the

Preview to preview the layout in the Print Previewprinted.

47

open, select each scenario in turn

, the mach number problem on Tail

on the Quickon at the upper left corner of

from the Application Menu.

Printing Data and Results

from the Application

the items that you want to print.box to print the results for all of the

t the current scenario. If you want to print to a file,in the Save dialog

window before

3 Developing the Model 49

3 Developing the Model


Overview

Data Requirements

Opening the Old Model

Updating the Model

Defining the Scenarios

Defining the Sources

Sizing the Network

Design Calculations

OverviewIn this chapter of the Getting Started tutorial you will change the networkdesigned in Chapter 2 to model the tie-in of two new control valves into ourcurrent system. The modified system will be simulated for two new scenarios,one each for the new sources.

This tutorial assumes that you are familiar with the use of Microsoft Windowsand have some prior experience in the design of flare systems.

Note: This tutorial is a continuation of the one in the previous chapter andrequires that you complete that chapter before continuing with this one.

This example consists of the following main parts:

1 Building The Pipe Network - Pipes and nodes will be added using eitherthe Process Flowsheet or the Manager views.

2 Defining the Scenarios - Different scenarios will be set up to simulatevarious process conditions.

3 Defining The Sources - Relieving sources will be added to each scenario.

4 Sizing the Network - Finally, the pipe network will be simulated andresults will be viewed both in textual and graphical form.

50

Data RequirementsBefore you can start to upgrade a computer model of the existing flare headersystem, you must first define al

Pipe Segment DataData

Connectivity

Length and fittingsloss coefficients fornew pipe segment

Diameter and pipeschedule for eachpipe segment

Note: When you are sizing a flare system, the initial pipe diameters mayaffect the solution when there is a liquid phase and the liquid knockout drumis modelled. You should initially size a network using vapo

The following diagram shows the connectivity of the system which includesthe new sources you will be adding in this example.

Fig 3.1

The pipe segments in the network diagram are detailed in the following table.

SegmentName

Length(m)

Stack 100

Header 1 50

3 Developin

Data RequirementsBefore you can start to upgrade a computer model of the existing flare headersystem, you must first define all the data that will determine your system.

Pipe Segment DataDescription

You would normally have prepared a system sketch thatdefines the nodes to which the new pipe segments areconnected.

Length and fittingsloss coefficients for

w pipe segment

These will be based upon either a preliminary or detailedisometric drawing of the piping.

Diameter and pipeschedule for each

If you are rating an existing network, these will normally betaken from the flare system P&ID. If you are sizing a newflare system, the pipe diameters that you define arerelatively unimportant since they will be overwritten by thesizing algorithms. It is recommended that reasonablediameters be defined, so that the sizing algorithm initialisesto a condition that will give faster convergence.

When you are sizing a flare system, the initial pipe diameters mayaffect the solution when there is a liquid phase and the liquid knockout drumis modelled. You should initially size a network using vapour phase methods.

The following diagram shows the connectivity of the system which includesthe new sources you will be adding in this example.


Length(m)

NominalDiameter (inch)

Schedule FittingsLoss

100 36 40 0

28 30 0


Before you can start to upgrade a computer model of the existing flare headerl the data that will determine your system.

You would normally have prepared a system sketch thatdefines the nodes to which the new pipe segments are

These will be based upon either a preliminary or detailed

If you are rating an existing network, these will normally beyou are sizing a new

flare system, the pipe diameters that you define arerelatively unimportant since they will be overwritten by thesizing algorithms. It is recommended that reasonablediameters be defined, so that the sizing algorithm initialises

condition that will give faster convergence.

When you are sizing a flare system, the initial pipe diameters mayaffect the solution when there is a liquid phase and the liquid knockout drum

ur phase methods.

The following diagram shows the connectivity of the system which includes


Fittings ElevationChange (m)

100

0


SegmentName

Length(m)

NominalDiameter (inch)

Schedule FittingsLoss

ElevationChange (m)

Header 2 50 28 30 0 0

Header 3 50 36 40 0 0

Tail Pipe 1 25 18 40 0 0

Tail Pipe 2 25 18 40 0 0

Tail Pipe 3 25 12 40 0 0

Tail Pipe 4 25 18 40 0 0

The new pipe segments Header 1, Header 2, Tail Pipe 3 and Tail Pipe 4 will beadded.

Relief Source DataThe following data must be specified for the sources:

Data Description

Flow andComposition

These may vary for each scenario that you are evaluating.If a relief source is not used in a particular scenario, theflow may be set to zero. The Flow refers to the quantity offluid that the source valve must pass as a consequence ofthe plant upset condition. The Rated Flow refers to thequantity of fluid that the source valve will pass due to itsphysical construction. Rated flow must always be greaterthan or equal to flow.

Maximum AllowableBack Pressure(MABP)

This is the maximum pressure that can exist at the outlet ofthe device (source) without affecting its capacity.

DownstreamTemperature

This temperature is used as the pressure independenttemperature at which the source enters the network. Thistemperature is used when ideal gas enthalpies are used tocalculate the heat balance, or as an initial guess when anyother enthalpy method is used.

Upstream Pressureand Temperature

These are only used if the Ideal Gas enthalpies are notused for the heat balance. These may vary for eachscenario that you are evaluating. With relief valves, theflowing pressure should be used.

Discharge FlangeSize

This will normally be determined from the relief valve sizingcalculations.

In this example, you will consider five scenarios that represent one fire caseand four single blocked discharge cases. The following tables define thesource data for each scenario.

The discharge flange size values are left undefined. In this case, they areassumed to have the same diameter as the attached pipes

Default Source Data

SourceName

Flowrate(kg/hr)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 100000 20 15 15 10 5.0

52 3 Developing the Model

SourceName

Flowrate(kg/hr)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 2 100000 25 15 15 10 5.0

Source 3 100000 30 15 15 10 5.0

Source 4 100000 35 15 15 10 5.0

Source 1 Only Data

SourceName

Flowrate(kg/hr)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 100000 20 15 15 10 5.0

Source 2 0 25 15 15 10 5.0

Source 3 0 30 15 15 10 5.0

Source 4 0 35 15 15 10 5.0

Source 2 Only Data

SourceName

Flowrate(kg/hr)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 0 20 15 15 10 5.0

Source 2 100000 25 15 15 10 5.0

Source 3 0 30 15 15 10 5.0

Source 4 0 35 15 15 10 5.0

Source 3 Only Data

SourceName

Flowrate(kg/hr)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 0 20 15 15 10 5.0

Source 2 0 25 15 15 10 5.0

Source 3 100000 30 15 15 10 5.0

Source 4 0 35 15 15 10 5.0

Source 4 Only Data

SourceName

Flowrate(kg/hr)

Mol.Wt.

USTemp(C)

DSTemp(C)

US Pres.(barabs)

MABP(barabs)

Source 1 0 20 15 15 10 5.0

Source 2 0 25 15 15 10 5.0

Source 3 0 30 15 15 10 5.0

Source 4 100000 35 15 15 10 5.0


System Design ConstraintsIn this case, the following data is used for all

Maximum allowable mach numbertailpipes.

Maximum Noise

Opening the Old Model1 Start Aspen Flare System Analyzer

that you have just saved in

2 Click Open from theaspenONE Button

-or-

Click the aspenONE Bthat is displayed

-or-

Press Alt then

3 The Open File

Fig 3.2

4 Click the Look in

System Design ConstraintsIn this case, the following data is used for all scenarios:

Maximum allowable mach number - 0.50 for both main headers and

Maximum Noise – 100 dB for both main headers and tailpipes.

Opening the Old ModelAspen Flare System Analyzer and open the previously stored case

that you have just saved in Chapter 2.

from the Quick Access Toolbar that is docked beside theaspenONE Button on the upper left corner of the application window

aspenONE Button, then click Open from the Application Menuthat is displayed.

then 2.

Open File dialog box will be displayed.

Look in field to select the appropriate disk drive and directory.

53

for both main headers and

dB for both main headers and tailpipes.

and open the previously stored case

that is docked beside theupper left corner of the application window.

from the Application Menu

to select the appropriate disk drive and directory.

54

5 Next, select the fileclick Open.

Updating the ModelYou need to add new pipe segments to the existing model, but first you mustdelete the connection betweenFlowsheet and delete the co

1 Click Toggle Connect/Arrange Modeon the Ribbonbetween Tee 1

Fig 3.3

2 Press DELETE.back to Arrange

To add a Tee section after

3 Open the Node ManagerHome tab on the Rib


select the file that you created in Chapter 2 from the list

Updating the ModelYou need to add new pipe segments to the existing model, but first you mustdelete the connection between Tee 1 and Header 3. Open the P

and delete the connection as follows:

Toggle Connect/Arrange Mode on the Process Flowsheeton the Ribbon to switch to Connect mode and select the connection

Tee 1 and Header 3.

. Click Toggle Connect/Arrange Mode again to switchArrange mode.

ee section after Header 3:

Node Manager by clicking Nodes in the Build group on thetab on the Ribbon.


from the list, and then

You need to add new pipe segments to the existing model, but first you must. Open the Process

Process Flowsheet tabmode and select the connection

again to switch

group on the


Fig 3.4

4 Click Add and select

The Tee Editor

and select Tee from the list that is displayed. Click

Tee Editor will be displayed:

55

Click Edit.

56

Fig 3.5

5 Specify the name to beHeader 3 and select

Note: Since this example is of smaller size, therefore thebe left blank. This field is only useful for larger case with multiple sections(areas) within a same plant.

6 Move to the Calculationssetting is Miller


8 Click Close to close the

Now, you can add two pipe segments to the upstream and branch sectionof Tee 3 using the

9 Open the Pipe Manager


Specify the name to be Tee 3, the Downstream node connection to beand select Upstream from the At field.

Since this example is of smaller size, therefore the Locationbe left blank. This field is only useful for larger case with multiple sections(areas) within a same plant.

Calculations tab and verify that the Fitting Loss MethodMiller.


to close the Node Manager.

n add two pipe segments to the upstream and branch sectionusing the Pipe Manager.

Pipe Manager by clicking Pipes in the Build group


connection to be

Location field willbe left blank. This field is only useful for larger case with multiple sections

Fitting Loss Method

n add two pipe segments to the upstream and branch section

group.


Fig 3.6

10 Click Add to add a new pi

11 Change the default pipe name to


to add a new pipe segment. Click Edit to open the

Change the default pipe name to Tail Pipe 4.


57

to open the Pipe Editor.


58

Fig 3.7


14 Select Nominal Diameter

15 Click OK to close thesegment.

16 Change the default name of

17 Specify Tee 3Upstream in the


19 Set Nominal Diameterprovided.



Nominal Diameter as 18 inch from the list provided

close the Pipe Editor. Repeat Step 10 to add another pipe

default name of the new pipe segment to Header 2

Tee 3 as the Downstream node connection and selectin the At field.


Nominal Diameter as 28 inch and Schedule as 30 from the list


25 m.

provided.

to add another pipe

Header 2.

connection and select

50 m.

from the list


Fig 3.8



Notice that three new objects have been added to the PYou can manually arrange them by clicking and dragging the object icons.

Now you will add a tee section using the

22 Open the Palettethe Process Flowsheet

23 Click the TeeFlowsheet.

Since the Edit Objects on Addbe displayed.



Notice that three new objects have been added to the ProcessYou can manually arrange them by clicking and dragging the object icons.

Now you will add a tee section using the Palette.

Palette (if it is not displayed) by clicking the PaletteProcess Flowsheet tab on the Ribbon.

Tee icon in the Palette window, drag and drop it to the Process

Edit Objects on Add check box is selected, The

59

rocess Flowsheet.You can manually arrange them by clicking and dragging the object icons.

alette icon on

, drag and drop it to the Process

box is selected, The Tee Editor will

60

Fig 3.9

24 Change the default name to

25 Specify Header 2Upstream in theloss method


Now, you can add twoof Tee 2 using the

27 Click the Pipenew pipe segment.

28 On the Pipe Edi



Change the default name to Tee 2.

Header 2 as the Downstream node connection and selectin the At field. On the Calculations tab, verify

loss method is Miller.


Now, you can add two pipe segments to the upstream and branch sectionusing the Palette.

Pipe icon, drag and drop it onto the Process Flowsheetnew pipe segment.

Pipe Editor, change the default pipe name to Tail Pipe 3



connection and selectverify the Fitting

pipe segments to the upstream and branch section

icon, drag and drop it onto the Process Flowsheet to add a

Tail Pipe 3.



Fig 3.10


31 Verify that the

32 Close the Pipe Editor

33 Repeat Step 27

34 Change the default name of the

35 Specify Tee 2Upstream in the

36 Specify Tee 1the At field.




Verify that the Nominal Diameter is 12 inch.

Pipe Editor by clicking OK.

Repeat Step 27 to add another pipe segment.

default name of the new pipe segment to Header 1

Tee 2 as the Downstream node connection and selectin the At field.

1 as the Upstream connection and select Downstream


Nominal Diameter as 28 inch and Schedule as 30.

61

25 m.

Header 1.

connection and select

Downstream in

50 m.

62

Fig 3.11


Select Inputs |Pipes data sheet

Fig 3.12

At this point you might want to reaFlowsheet. The P



Inputs | Pipes from the Views menu on the Navigation Panedata sheet displays the data for all of the pipe segments:

At this point you might want to rearrange the new items on the P. The Process Flowsheet should be similar as displayed


Navigation Pane. Thedisplays the data for all of the pipe segments:

rrange the new items on the Processdisplayed below:


Fig 3.13

Defining the ScenariosYou now need to define the data for the new scenarios, theand Source 4 Onlyscenarios which you will still be using in this example. To add the newscenarios:

1 Click Scenario

The Scenario Manager

Defining the ScenariosYou now need to define the data for the new scenarios, the Source 3 Only

Source 4 Only scenarios. The existing model already contains threescenarios which you will still be using in this example. To add the new

Scenarios in the Build group on the Home tab on the Ribbon

Scenario Manager will be displayed.

63

Source 3 Onlymodel already contains three

scenarios which you will still be using in this example. To add the new

tab on the Ribbon.

64

Fig 3.14

2 Click Default ScenarioA new scenario is added to the list.


Default Scenario in the Scenarios list to highlight it. ClickA new scenario is added to the list.


list to highlight it. Click Clone.


Fig 3.15

3 Click Edit to open the

4 Change the default name toverify that theTailpipes groups are

to open the Scenario Editor.

Change the default name to Source 3 Only. On the Constraintsthe values of the Mach Number in both Headersgroups are 0.5 as shown below:

65

Constraints tab,Headers and

66

Fig 3.16

5 Repeat Step 2 t

6 Change the default name for the new scenario to


Repeat Step 2 to add a new scenario. Click Edit.

Change the default name for the new scenario to Source 4 Only


Source 4 Only.


Fig 3.17

7 Verify that the values of theboth Headers

8 Click OK to close theManager. Now selectthe working scenario. Click

Defining the SourcesYou will now enter the source data for the sources in all scenarios. Since forthe first part of the example you will be defining the source compositions interms of molecular weight, the program preferences must be set to acceptthe compositions on this basis as described in

1 Click Nodes in

The Node Manager

Verify that the values of the Mach Number on the ConstraintsHeaders and Tailpipes groups are 0.5.

to close the Scenario Editor and return to the ScenarioNow select Default Scenario and click Current

the working scenario. Click Close to close the Scenario Manager

Defining the SourcesYou will now enter the source data for the sources in all scenarios. Since forthe first part of the example you will be defining the source compositions interms of molecular weight, the program preferences must be set to accept

compositions on this basis as described in Chapter 2.

in the Build menu on the Home tab.

Node Manager will be displayed.

67

Constraints tab in

ScenarioCurrent to make this

Scenario Manager.

You will now enter the source data for the sources in all scenarios. Since forthe first part of the example you will be defining the source compositions interms of molecular weight, the program preferences must be set to accept

68

Fig 3.18

2 Click Add and select


and select Control Valve from the list displayed


displayed.


Fig 3.19

Click Edit. TheThe Control Valve Editor will be displayed:

69

70

Fig 3.20

3 Change the default name tofield and set connection to be at

4 Move to the Conditions


Change the default name to Source 3. Select Tail Pipe 3and set connection to be at Upstream (of Tail Pipe 3

Conditions tab and set the Mass Flow as 100000


in the Outletil Pipe 3).

100000 kg/hr.


Fig 3.21

5 On the Composition

Note: The composition will be calculated asMol. Wt. field.

Composition tab, specify the Mol. Wt. to be 30.

The composition will be calculated as soon as you tab away from the

71

soon as you tab away from the

72

Fig 3.22

Note: The Mole FractionsWeight. Becausematch the Molecular Weight.


7 Repeat Step 2 to add a new source.Control Valve Editor

8 Name the new source as

9 Select Tail Pipe 4Upstream (of


Mole Fractions are automatically estimated from the MolecularWeight. Because HC is selected, only hydrocarbon components will be used tomatch the Molecular Weight.

to close the Control Valve Editor for Source 3.

Repeat Step 2 to add a new source. Again select Control ValveControl Valve Editor will be displayed.

ew source as Source 4.

Tail Pipe 4 in the Outlet field and set connection to be at(of Tail Pipe 4).


are automatically estimated from the Molecularis selected, only hydrocarbon components will be used to

Control Valve and the

and set connection to be at


Fig 3.23

10 Repeat 4-6 to add all the information required by the scenMole Wt. to be


The Node Manager

to add all the information required by the scenario. Specifyto be 35 on the Composition tab.

to close the Control Valve Editor.

Node Manager will now appear as follows:

73

ario. Specify

74

Fig 3.24

12 Close the Node Manager

13 Select Inputs |

The Sources

Fig 3.25

14 You must now add the source

15 Select the scenarios from theHome tab. Any open data views will display data for the selectedscenario.

Make the following changes to the flowrates i

Scenarios Source 1(kg/hr)

Source 1 Only 100000


Node Manager by clicking Close.

Inputs | Sources from the Views menu on the Navigation Pane

data sheet for the Default Scenario will be displayed:

You must now add the source data for the four scenarios.

Select the scenarios from the Scenario Selector in the Run. Any open data views will display data for the selected

Make the following changes to the flowrates in all scenarios:

Source 1(kg/hr)

Source 2(kg/hr)

Source 3(kg/hr)

100000 0 0


Navigation Pane.

will be displayed:

Run group on the. Any open data views will display data for the selected

Source 4(kg/hr)

0


Scenarios Source 1(kg/hr)

Source 2(kg/hr)

Source 3(kg/hr)

Source 4(kg/hr)

Source 2 Only 0 100000 0 0

Source 3 Only 0 0 100000 0

Source 4 Only 0 0 0 100000

For each scenario, ensure that the sources which have a flowrate of 0 areignored (i.e. select the Ignore check box for the source).

Note: You can also add the single source scenarios by selecting the AddSingle Source Scenarios tool from Source Tools in Tools group on theHome tab.

Sizing the NetworkYou have now entered all the model data and can now make the sizingcalculations. You will need to set the calculation options before starting thecalculations.

1 Select Options in the Run group on the Home tab. The CalculationOptions Editor will be displayed:

76

Fig 3.26

2 For the first calculation of this example ensure that the following optionsare set:

On the GeneralHeat Transfercheck box should be cleared,Design Mode


For the first calculation of this example ensure that the following options

General tab, Calculation Mode should be set to RatingHeat Transfer check box should be cleared, Include Kinetic Energy

box should be cleared, Ignore Source to Pipe Pressure Loss inDesign Mode should be selected.


For the first calculation of this example ensure that the following options

Rating, EnableInclude Kinetic Energy

Ignore Source to Pipe Pressure Loss in


On the ScenariosScenario.

On the MethodsGas, the Enthalpy Methodmethods to Isothermal Gas

3 Click OK to close theDefault Scenariotab.


4 Click Run in the

Fig 3.27

Once the calculations are complete you can review the results

5 Select ResultsPane. The Messages

Fig 3.28

The above view contains general information and warning messagesregarding the calculations. In this case the mach number exceeds thedesign value ofIt also shows both upstream and downstream pipe segment mach numberfor each violation. It is due to smaller pipe segments causing very highfluid velocities across the pipe segment.

At this point, it is a good idea to save your case before doing detaildesign.

6 Click the aspenONE Button on the upper left corner of the applicationwindow, and then selectdisplayed. Save

Scenarios tab, the Calculate box should be set to

Methods tab, the VLE Method should be set to CompressibleEnthalpy Method to Ideal Gas and all the Pressure Drop

Isothermal Gas.

to close the Calculation Options Editor. Ensure that theDefault Scenario is selected using the Scenario Selector


the Run group.

Once the calculations are complete you can review the results

Results | Messages from the Views pane on the NavigationMessages sheet will be displayed.

The above view contains general information and warning messagesregarding the calculations. In this case the mach number exceeds the

ue of 0.5 for Tail Pipe 3, which was defined for each scenario.It also shows both upstream and downstream pipe segment mach numberfor each violation. It is due to smaller pipe segments causing very highfluid velocities across the pipe segment.

point, it is a good idea to save your case before doing detail

Click the aspenONE Button on the upper left corner of the applicationwindow, and then select Save As from the Application Menu

ave the file as Getting Started 2 Rating.fnw

77

should be set to Current

CompressiblePressure Drop

Ensure that theScenario Selector on the Home


Navigation

The above view contains general information and warning messagesregarding the calculations. In this case the mach number exceeds the

, which was defined for each scenario.It also shows both upstream and downstream pipe segment mach numberfor each violation. It is due to smaller pipe segments causing very high

point, it is a good idea to save your case before doing detail

Click the aspenONE Button on the upper left corner of the applicationenu that is

Started 2 Rating.fnwx.

78

Design Calculations1 We will now use

redesign the network to resolve the mach number problem we haveidentified in the rat

Use the Calculation Modethe Ribbon to change the calculation mode tocalculation mode will redesign the flare system to meet our definedsystem limits

2 Click the Run

After the calculation has been completed, you can review the new results.

Fig 3.29

3 Select ResultsSizing tab to see a list of changes thatmade to the network

4 Select Results | Pressure/Flow Summary

The Pressure/Flow Summary

Fig 3.30


Design CalculationsWe will now use Aspen Flare System Analyzer's design capabilities toredesign the network to resolve the mach number problem we haveidentified in the rating calculation we have just completed.

Calculation Mode selector in the Run group on theto change the calculation mode to Debottleneck

calculation mode will redesign the flare system to meet our definedsystem limits without reducing the current sizes of any pipes.

Run icon on the Ribbon.


Results | Messages from the Views pane, and then select thetab to see a list of changes that Aspen Flare System Analyzer

made to the network.

Results | Pressure/Flow Summary.

Pressure/Flow Summary data sheet will be displayed


's design capabilities toredesign the network to resolve the mach number problem we have

ing calculation we have just completed.

group on the Home tab ofDebottleneck. This

calculation mode will redesign the flare system to meet our definedwithout reducing the current sizes of any pipes.


and then select theAspen Flare System Analyzer has

be displayed.


Notice that the upstream and downstream mach numbers are now withinthe design specification for the given scenario. You can use the bottomscroll bar to move across the columns.

We now have a flare system that is designed correctScenario where all sources are relieving but we have not yet checkedthat it is adequate for all of the scenarios. To do this we will do acalculation for all of the scenarios.

5 Open the Calculatiogroup on theGeneral tab. On theScenarios. After closing theicon to run the rating check.

6 When the calculations have finished,Views pane. Click thedesign limits will be displayed. You will see thatAnalyzer has detected a violation of the mach number limits for the tailpipes in the single source scenarios.

Fig 3.31

The reason for this is that the lower back pressure in the system whenonly a single source is relieving means that theresulting in higher velocities.

7 To fix this problem with our design we will recalculations for all the scenarios. Use thethe Ribbon to change theclick the Run

8 When completeconfirm that the flare system now meets all our design limits in allscenarios. The


We now have a flare system that is designed correctly for thewhere all sources are relieving but we have not yet checked

that it is adequate for all of the scenarios. To do this we will do acalculation for all of the scenarios.

Calculation Options Editor by clicking Optionsgroup on the Home tab. Set the Calculation Mode to Rating

tab. On the Scenarios tab, set the Calculate option to. After closing the Calculation Options Editor, click the

to run the rating check.

When the calculations have finished, select Results | Messages. Click the Problems tab where any violations of our system

design limits will be displayed. You will see that Aspen Flare Systemhas detected a violation of the mach number limits for the tail

pipes in the single source scenarios.

The reason for this is that the lower back pressure in the system whenonly a single source is relieving means that the gas density is reducedresulting in higher velocities.

To fix this problem with our design we will re-run the Debottleneckcalculations for all the scenarios. Use the Calculation Mode

to change the calculation mode to DebottleneckRun icon.

When completed, review the Problems tab of the Messagesconfirm that the flare system now meets all our design limits in allscenarios. The Sizing tab will show which pipe sizes have been increased.

79

Notice that the upstream and downstream mach numbers are now withinthe design specification for the given scenario. You can use the bottom

ly for the Defaultwhere all sources are relieving but we have not yet checked

that it is adequate for all of the scenarios. To do this we will do a Rating

Options in the RunRating on theoption to All

, click the Run

Messages from thetab where any violations of our system

n Flare Systemhas detected a violation of the mach number limits for the tail

The reason for this is that the lower back pressure in the system whengas density is reduced

DebottleneckCalculation Mode selector on

Debottleneck and then

Messages view toconfirm that the flare system now meets all our design limits in all

ill show which pipe sizes have been increased.

80

Fig 3.32

Note: We could have run theimmediately after our first rating calculation and obtained the same results.While this might have been faster, we have obtaiof which scenarios have caused changes to pipe sizes by doing ourcalculations in stages.

9 Select ResultsNavigation Pane

The Pressure/Flow Summ

Fig 3.33


We could have run the Debottleneck calculations for all scenariosimmediately after our first rating calculation and obtained the same results.While this might have been faster, we have obtained a better understandingof which scenarios have caused changes to pipe sizes by doing ourcalculations in stages.

Results | Pressure/Flow Summary from the ViewNavigation Pane.

Pressure/Flow Summary will be displayed.


calculations for all scenariosimmediately after our first rating calculation and obtained the same results.

ned a better understandingof which scenarios have caused changes to pipe sizes by doing our

Views pane on the



10 Click the aspenONE Button on the upper left corner of the applicationwindow, and then select Save As from the Application Menu to save thecase as a new file.

11 Enter the new file name as Getting Started 2 Design.fnwx in the AllFiles dialog box and click Save.

AspenFlareSysAnalV7 3 Start

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