Flarenet - Getting Started Guide - 2008 - baixardoc

Aspen Flare

System Analyzer

Getting Started Guide

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Version Number: 7.0

Copyright (c) 1981-2008 by Aspen Technology, Inc. All rights reserved.

Flare System Analyzer is a registered trademark 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. 200 Wheeler Road Burlington, MA 01803-5501

USA Phone: (781) 221-6400

Toll free: (888) 996-7001

Website http://www.aspentech.com



1 Introduction 1

Contents

1 Introduction.........................................................................................................2

About this document ...................................................................................... 2

Audience....................................................................................................... 2

Related Documentation................................................................................... 2

Technical Support .......................................................................................... 2

2 Overview..............................................................................................................4

Overview ...................................................................................................... 4

Data Requirements......................................................................................... 5

Pipe Segment Data............................................................................... 5

Relief Source Data................................................................................ 6

System Design Constraints .................................................................... 7

Starting Flare System Analyzer ........................................................................ 8

Starting a New Model...................................................................................... 8

Saving the Model ..........................................................................................10

Building the Pipe Network...............................................................................12

Defining the Scenarios ...................................................................................21

Defining the Sources .....................................................................................25

Rating the Network .......................................................................................31

Printing Data and Results ...............................................................................33

3 Developing the Model.........................................................................................34

Overview .....................................................................................................34

Data Requirements........................................................................................34

Pipe Segment Data..............................................................................35

Relief Source Data...............................................................................36

System Design Constraints ...................................................................38

Opening the Old Model...................................................................................38

Updating the Model .......................................................................................39

Defining the Scenarios ...................................................................................45

Defining the Sources .....................................................................................47

Sizing the Network ..............................................................................51

Design Calculations .......................................................................................53



2 1 Introduction

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 called "Flarenet").

Audience This guide is intended for process and process systems engineers.

Related Documentation

Title Content

Flare System Analyzer Reference

Manual

Reference Manual for Using 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



1 Introduction 3

• 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.



4 2 Overview

2 Overview

This section provides information on the following topics:

• Overview

• Data Requirements

• Starting 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 Flare System Analyzer to design and rate a new flare system. This

"guided tour" will expose you to most of the major features of Flare System Analyzer.

This tutorial assumes that you are familiar with the use of 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 PFD or the Manager views.

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.



2 Overview 5

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.

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

loss coefficients for

each pipe segment

These will be based upon either a preliminary or detailed

isometric drawing of the piping.

Diameter and pipe

schedule for each

pipe segment

If you are rating an existing network, these will normally be

taken from the flare system P&ID. If you are sizing a new

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 1.1

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.



6 2 Overview

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

Item Length

(m)

Internal

Diameter

(mm)

Wall

Thickness

(mm)

Fittings

Loss

Elevation

Change

(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 connect 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

Composition

These may vary for each scenario that you are evaluating. If a

relief source is not used in a particular scenario the flow may

be set to zero. The Flow refers to the quantity of fluid that the

source valve must pass as a consequence of the plant upset

condition. The 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

Back Pressure

(MABP)

This is the maximum pressure that can exist at the outlet of

the device (source) without affecting its capacity.

Downstream

temperature

This temperature is used as the pressure independent

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 is used.

Upstream pressure

and temperature

These are only used if Ideal Gas enthalpies are not used for

the heat balance. These may vary for each scenario that you

are evaluating. With relief valves, the flowing pressure should

be used.

Discharge flange

size

This will normally be determined from the relief valve sizing

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.



2 Overview 7

Default Source Data

Source

Name

Flowrate

(kg/hr)

Flange

Size

(mm)

Mol.

Wt.

US

Temp

(C)

DS

Temp

(C)

US

Pres.

(bar

abs)

MABP

(bar

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

Name

Flowrate

(kg/hr)

Flange

Size

(mm)

Mol.

Wt.

US

Temp

(C)

DS

Temp

(C)

US

Pres.

(bar

abs)

MABP

(bar

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

Name

Flowrate

(kg/hr)

Flange

Size

(mm)

Mol.

Wt.

US

Temp

(C)

DS

Temp

(C)

US

Pres.

(bar

abs)

MABP

(bar

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.



8 2 Overview

Starting Flare System Analyzer The installation process creates a short-cut to Flare System Analyzer in the Start menu under Programs > AspenTech To Start Flare System Analyzer,

1 Select the Start menu.

2 Navigate to and click the Flarenet icon under Programs > AspenTech >

Aspen Engineering Suite.

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

When you start Flare System Analyzer, the Flare System Analyzer Desktop

appears. Before setting up the Getting Started case, you should choose the Flare System Analyzer units set for displaying information. You can check

your current units set by accessing the Preferences Editor:

1 Select File > Preferences and the Preferences Editor view will open.

2 The current unit set is shown in the Units drop-down list. The Flare System Analyzer default is Metric, which will be used for this example.

3 Confirm that the Edit Objects on Add checkbox is active (checked). This option will open the object editor view each time a new object is added.

4 Click the OK button to close the Preferences Editor view.

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

1 Select File-New on the main program menu bar.

2 Click the New Case icon.

The Description Editor view appears.

3 Enter the appropriate data (as shown in Figure 1.6) into the User Name,

Job Code, Project, and Description fields, and then click the OK button.

The Component Manager view then appears.



Flarenet - Getting Started Guide - 2008 - baixardoc

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