Aspen Flare System Analyzer. Getting Started Guide v.8.0

81 Pages·2.73 MB·English

Aspen Flare System Analyzer
Getting Started Guide
Version Number: V8.0
December 2012
Copyright (c) 1981-2012 by Aspen Technology, Inc. All rights reserved.
Aspen Flare System Analyzer, Aspen Flarenet, and the aspen leaf logo are trademarks or registered
trademarks of Aspen Technology, Inc., Burlington, MA. All other brand and product names are
trademarks or registered trademarks of their respective companies.
This document is intended as a guide to using AspenTech's software. This documentation
contains AspenTech proprietary and confidential information and may not be disclosed,
used, or copied without the prior consent of AspenTech or as set forth in the applicable
license agreement. Users are solely responsible for the proper use of the software and the
application of the results obtained.
Although AspenTech has tested the software and reviewed the documentation, the sole
warranty for the software may be found in the applicable license agreement between
AspenTech and the user. ASPENTECH MAKES NO WARRANTY OR REPRESENTATION, EITHER
EXPRESSED OR IMPLIED, WITH RESPECT TO THIS DOCUMENTATION, ITS QUALITY,
PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE.
Aspen Technology, Inc.
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USA
Phone: [phone]
Toll free: [phone]
Website http://www.aspentech.com
Contents
1 Introduction.........................................................................................................2
About this document.........................................................................................2
Audience.........................................................................................................2
Related Documentation.....................................................................................2
Technical Support ............................................................................................2
2 Building and Running a Model..............................................................................4
Overview.........................................................................................................4
Data Requirements...........................................................................................5
Pipe Segment Data.................................................................................5
Relief Source Data..................................................................................6
System Design Constraints......................................................................7
Starting Aspen Flare System Analyzer.................................................................7
Starting a New Model........................................................................................8
Saving the Model ...........................................................................................12
Building the Pipe Network ...............................................................................12
Starting the Pipe Network .....................................................................12
Completing the Pipe Network.................................................................16
Defining the Scenarios....................................................................................26
Defining the Sources ......................................................................................33
Rating the Network ........................................................................................44
Printing Data and Results................................................................................47
3 Developing the Model.........................................................................................49
Overview.......................................................................................................49
Data Requirements.........................................................................................50
Pipe Segment Data...............................................................................50
Relief Source Data................................................................................51
System Design Constraints....................................................................53
Opening the Old Model....................................................................................53
Updating the Model ........................................................................................54
Defining the Scenarios....................................................................................63
Defining the Sources ......................................................................................66
Sizing the Network.........................................................................................73
Design Calculations........................................................................................75
1Introduction 1
1 Introduction
This section provides information on the following topics:
 About this Document
 Audience
 Related Documentation
 Technical Support
About this document
The guide provides step by step instructions to the most commonly used
features within Aspen Flare System Analyzer (previously named Aspen
Flarenet).
Audience
This guide is intended for process and process systems engineers.
Related Documentation
Title Content
Aspen Flare System Analyzer Reference Manual for Using Aspen
Reference Manual Flare System Analyzer
Technical Support
AspenTech customers with a valid license and software maintenance
agreement 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
 Search for tech tips, solutions and frequently asked questions (FAQs)
 Search for and download application examples
 Search for and download service packs and product updates
 Submit and track technical issues
 Send suggestions
 Report product defects
 Review lists of known deficiencies and defects
Registered users can also subscribe to our Technical Support e-Bulletins.
These e-Bulletins are used to alert users to important technical support
information such as:
 Technical advisories
 Product updates and releases
Customer support is also available by phone, fax, and email. The most up-to-
date contact information is available at the AspenTech Support Center at
http://support.aspentech.com.
1Introduction 3
2 Building and Running a
Model
This section provides information on the following topics:
 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
Overview
This Getting Started tutorial shows the fundamental principles involved in
using 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 Flare
System Analyzer.
This tutorial assumes that you are familiar with the use of Microsoft Windows
and 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 either
the Process Flowsheet or Pipe Manager.
2 Defining the Scenarios - Different scenarios will be set up to simulate
various 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 and
results will be viewed both in textual and graphical form.
Data Requirements
Before 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 the
solution when there is a liquid phase and the liquid knockout drum is
modeled. You should initially size a network using vapor phase methods.
Pipe Segment Data
Data Description
Connectivity You would normally have prepared a system sketch that
defines the nodes to which the pipe segments are connected.
Length and fittings These will be based upon either a preliminary or detailed
loss coefficients for isometric drawing of the piping.
each pipe segment
Diameter and pipe If you are rating an existing network, these will normally be
schedule for each taken from the flare system P&ID. If you are sizing a new
pipe segment flare system, the pipe diameters that you define are relatively
unimportant since they will be overwritten by the sizing
algorithms. It is recommended that reasonable diameters be
defined, so that the sizing algorithm initializes to a condition
that will give faster convergence.
The following diagram shows the connectivity of the system that you will be
designing in this example.
Fig 2.1
The piping in the network diagram is detailed in the following table:
2BuildingandRunningaModel 5
Item Length Internal Wall Fittings Elevation
(m) Diameter Thickness Loss Change
(mm) (mm) (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 zero
length piece of pipe with defined fittings loss coefficients. Since the internal
diameter is not specified, it will assume the same diameter as the upstream
pipe segment. Fittings loss coefficients for the flare tip exclude pipe
enlargement and junction losses for the connection to the upstream pipe
which will automatically be calculated.
Relief Source Data
The following data must be specified for the sources:
Data Description
Flow and These may vary for each scenario that you are evaluating. If a
Composition relief source is not used in a particular scenario, the flow may
be set to zero. Flow refers to the quantity of fluid that the
source valve must pass as a consequence of the plant upset
condition. Rated Flow refers to the quantity of fluid that the
source valve will pass due to its physical construction. Rated
Flow must always be greater than or equal to Flow.
Maximum Allowable This is the maximum pressure that can exist at the outlet of
Back Pressure the device (source) without affecting its capacity.
(MABP)
Downstream This temperature is used as the pressure independent
temperature temperature at which the source enters the network. This
temperature is used when ideal gas enthalpies are used to
calculate the heat balance, or as an initial guess when any
other enthalpy method isused.
Upstream pressure These are only used if Ideal Gas enthalpies are not used for
and temperature the heat balance. These may vary for each scenario that you
are evaluating. With relief valves, the flowing pressure should
be used.
Discharge flange This will normally be determined from the relief valve sizing
size calculations. If this value is unknown then the field should be
left empty to ignore the pressure change from the valve to
the downstream pipe due to the swage.
In this example, you will consider three scenarios that represent one fire case
and two single blocked discharge cases. The following tables define the source
data for each scenario.
Default Source Data
Source Flowrate Flange Mol. US DS US Pres. MABP
Name (kg/hr) Size Wt. Temp Temp (bar (bar
(mm) (C) (C) abs) abs)
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
Source Flowrate Flange Mol. US DS US Pres. MABP
Name (kg/hr) Size Wt. Temp Temp (bar (bar
(mm) (C) (C) abs) abs)
Source 1 100000 300 20 15 15 10 5.0
Source 2 0 300 25 15 15 10 5.0
Source 2 Only Data
Source Flowrate Flange Mol. US DS US Pres. MABP
Name (kg/hr) Size Wt. Temp Temp (bar (bar
(mm) (C) (C) abs) abs)
Source 1 0 300 20 15 15 10 5.0
Source 2 100000 300 25 15 15 10 5.0
System Design Constraints
In this case, the following data is used for both scenarios:
 Maximum allowable mach number - 0.50 for both main headers and
tailpipes.
 Maximum allowable noise – 100 dB for both main headers and tailpipes.
Starting Aspen Flare System
Analyzer
The installation process creates a short-cut to Aspen Flare System Analyzer in
the Start menu.
To Start Aspen Flare System Analyzer:
1 Select the Start menu.
2 Navigate to and click the Aspen Flare System Analyzer icon under
Programs | 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 System
Analyzer application window appears. Before setting up the Getting Started
case, you should choose the Aspen Flare System Analyzer units set for
displaying information. You can check your current units set by accessing the
Preferences Editor:
2BuildingandRunningaModel 7
1 Click the aspenONE Button which is on the upper left corner of the
application window; then select Preferences from the Application Menu.
The Preferences Editor is displayed.
Fig 2.2
2 The current unit set is shown in the Units box. The default unit set is
Metric, which will be used for this example.
3 Confirm that the Edit Objects on Add check box is selected. This option
will open the object editor view each time a new object is added.
4 Click OK to close the Preferences Editor.
Starting a New Model
To start a new case, do one of the following:
1 Click New on the Quick Access Toolbar beside the aspenONE Button; or,
click the aspenONE Button, then click New from the Application Menu.
The Documentation Editor is displayed.
2 Enter the appropriate data into the User Name, Job Code, Project, and
Description fields, and then click OK.
The Component Manager is displayed.