osenbroch dynamic flare

8/20/2019 Osenbroch Dynamic Flare

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Public © 2013 Aker Solutions Preferred partner

Preferred partner

Dynamic modelling and simulation of Flare Systems

Flow Assurance and Dynamic Simulations Seminar, Stavanger 29.10.2013

Jørgen Osenbroch | Process Specialist Engineer, Aker Solutions MMO




Introduction

14 November, 2013Slide 2




Typical simulation of flare systems

■ Traditional flare system design and capacity evaluations:

■ Steady State simulations traditionally performed■ Hysys Depr.Utility and Flarenet

■ Continuous peak flow

■ Flare system volume not accounted for

■ No accumulation in system

■ Conservative design

■ Advantage using Dynamic Simulations■ Includes packing effect in the flare system network

■ Peak flow and pressure staggered and delayed

■ Requires modelling of flare system





Typical flare simulation tools used by Aker Solutions

■ Hysys Depr. Utility (dynamic)

■ Flarenet (steady state)

■ OLGA (dynamic)

■ Hysys Dynamics (dynamic)

■ Selection criteria■ Gas or multiphase flow

■ Number of sources

■ Composition

■ Customer preference



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Project Background

■ Background:

■ Modification project on existing platform■ Tie-in of new fields → new equipment → increased blowdown volumes

■ Increased inlet separator pressure → higher initial blowdown rate

■ Static simulations → Flare KO drum peak pressure close to max

pressure allowed by design code (design pressure + 10%)

■ Sequential depressurisation introduced


Is there a more realistic and accurate approach ?


http://slidepdf.com/reader/full/osenbroch-dynamic-flare 8/38Public © 2013 Aker Solutions Preferred partner 14 November, 2013Slide 8

Hmm…


http://slidepdf.com/reader/full/osenbroch-dynamic-flare 9/38Public © 2013 Aker Solutions Preferred partner 14 November, 2013Slide 9

Ahaaaa..


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Dynamic Simulation Model for Blowdown & Flare System


■ Develop

■ Dynamic simulation tool for blow down segments and Flare Systems

■ Why■ Analyse packing effect and transient flow and pressure development

■ Benefit■ Minimise Project Execution cost (less modifications necessary)

■ Minimise sequential blowdown




Project Scope and Deliverables


■ Scope of Work

■ Base case: Total platform depressurisation (maximum gas to flare)■ Sensitivities related to■ Failure of sequential blow down

■ Blowdown of liquid segments

■ Deliverables

■ Tool for estimating BD segment volumes, weight and gas/liquid fraction■ Framework for modelling individual BD segments in Hysys Dynamics

■ Framework for modelling entire flare system in Hysys Dynamics




Development of Dynamic Flare Simulator

■ Tool: Hysys Dynamics (v7.3)

■ Challenge: Never done before in this scale (as far as we know)

■ Key to success: Good engineers, close collaboration with Company

and AspenTech focal point of contact

■ Approach■ All BD segments and entire Flare System modelled from isometrics

■ Headers and lines downstream BD valves modelled in detail using pipe

segments

■ Pipes without BD valves simplified (e.g. PV/PSV tailpipes)

■ Pipes less than 4” not included unless connected to BD valve

■ Blowdown segments/volumes modelled as vessels

■ Compared to Hysys Depressurizing Utility

■ Sequential blowdown included





A typical BD system


Output from

segment to

full model




HP Flare system - zoomed





HP Flare system


KO Drum

Flare tip




Simulation results





Dynamic Flare Model - Results

■ Adiabatic blowdown simulated

■ Failure of one BD valve with time delay■ Remaining BD valve time delays included





Dynamic Flare Model – Results (Massflow)


0

200000

400000

600000

800000

1000000

1200000

1400000

0 200 400 600 800 1000 1200 1400 1600 1800

M a s s f l o w

[ k g / h ]

Time [s]

Accumulated System Massflow

Flare Tip 43-FC01





Zoomed


0

200000

400000

600000

800000

1000000

1200000

1400000

0 50 100 150 200 250 300 350

M a s s f l o w [ k g / h ]

Time [s]


Flare Tip 43-FC01






0

200000

400000

600000

800000

1000000

1200000

1400000

0 50 100 150 200 250 300 350

M a s s f l o w

[ k g / h ]

Time [s]


Flare Tip 43-FC01


Flare Tip 43-FC01






KO Drum

Up-stream

meteringstation

XX FlareManifold

Upstream

flare tip




Dynamic Flare Model – Results (Pressure)


0

1

2

3

4

5

6

7

8

9

0 200 400 600 800 1000 1200 1400 1600 1800 2000

P r e s s u r e

[ b a r a ]

Time [s]

KO Drum 43-VD01Upstream Flare Metering station

Upstream Flare Tip 43-FC01

XX Flare Manifold





Zoomed


0

1

2

3

4

5

6

7

8

9

0 50 100 150 200 250 300 350 400 450 500

P r e s s u r e [ b

a r a ]

Time [s]

KO Drum 43-VD01

Upstream Flare Metering station


XX Flare Manifold






0

2

4

6

8

10

12

0 200 400 600 800 1000

P r e s s u r e

[ b a r a ]

Time [s]

KO Drum 43-VD01



XX Flare Manifold

KO Drum 43-VD01



XX Flare Manifold






DynamicSimulation

Steady StateSimulation

Peak pressure [bara]

KO Drum 8,34 10,86

XX Manifold 6,14 7,94

Upstream Flare

Tip

3,65 4,77

Peak mass flowrate [kg/h]

KO Drum 815 054 1 040 430

XX Manifold 149 527 159 190

Upstream Flare

Tip

932 052 1 199 620




Simulation model tested againstfield measurements





Dynamic Flare Model – Platform ESD blowdown

■ ESD 2.0 blowdown

■ Field data provided by Company■ Simulated in HYSYS Dynamic Flare Model

■ Simulation results compared against field measurements





Dynamic Flare Model – ESD blowdown


■ Well & Condensate segments - Pressure




Sleipner Dynamic Flare Model – Sleipner ESD blowdown


■ Well & Condensate segments Pressure




Summary





Dynamic Flare Model Project – Summary

■ The following has been developed:■ Framework for calculating BD segments volume, weight, gas/liquid

fractions

■ Methodology for modelling BD segments in Hysys Dynamics

■ Methodology for modelling and simulating Flare network

■ Provides a more realistic and accurate approach to Flare design

■ Better understanding of the dynamic behaviour during blow down

■ Easier to evaluate need and/or effect of sequential blow down


■ A fire model is also included.




Any questions?





Dynamic Flare Model – Platform ESD blowdown

Backup slides





Dynamic Flare Model - Backup





Dynamic Flare Model – Results (backup)




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osenbroch dynamic flare

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