04 -Seereeram - MEG

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part of Aker

© 2008 Aker Solutions

MEG Regeneration –Separation Challenges

Separasjonteknologi 2009

By Shanta Seereeram

Aker Process Systems AS

Aker Solutions



© 2008 Aker Solutions part of Aker Slide 2

Outline

■ MEG – General Overview

■ Separation Requirements■ Technology Experiences

■ Future Development

■ Summary




■ Formation of Hydrates

■ Characteristic for remotetie-back gas fields with long(e.g. 100-200km)multiphase pipelines

■ Risk of hydrate formation:

● Natural gas

● Free water present

● Low T - High P

■ A closed MEG loop willbecome contaminated withsalts/particles from the gas

production

MEG – General Overview

Typical Hydrate form ation curve

0

100

200

300

400

500

0 5 10 15 20 25 30

Temperature [degC]

P r

e s s u r e

[ b a r

HI




Closed loop MEG System

Slug Catcher

Condensate

Rich MEG Storage

Water, Salts, Corrosion Products

Lean MEG

Storage

Well stream:

Gas / condensate

Formation water

pH-stabilizer

Completion fluids

Corrosion inhibitor

Gas

processing

Pipeline corrosion

Condensate

MEG

Reclamation

MEG – General Overview

MEG Pre-

treatment

Rich

MEG

Lean

MEG

Condensed water




■ Rich MEG/Gas/Condensate Separation

● Flashing

● Gravity Separation

■ MEG/Water Separation

● Distillation

■ Salt separation

● Precipitation (in a controlled manner)

● Particle removal

Main Separation Requirements

Scale in pipeline

Scale in Distillation Column

Most challenging area in MEG Regeneration




Salt Separation

CHEMISTRY CONTROL

■ Low soluble salts (Ca2+, Mg2+, Fe2+, CO32-, HCO3

-)● Divalent cations will easily precipitate thus forming scale on undesired

locations at low concentrations

● Precipitation by alkalinity and temperature control

■ High soluble salts (Na+,K+, Cl-)● Monovalent cations may accumulate up to > 75000 mg/l without

precipitation

● Precipitation by evaporation

Precipitation in a controlled manner in specific locations

All salts must

be removed

Some levelcan be

tolerated




Ormen Lange

(Norsk Hydro)Full-stream Reclamation Shah Deniz

Vacuum boiling

Salt precipitation

Centrifuges


Temperature increase

Pressure decrease

Rich MEG Pre –

Treatment &

Storage

Lean MEG storage

and Injection

MEG

Reconcentration &

Reclamation

Low & high

Soluble salts

Rich MEG

Feed

Hydrocarbons Water




Ormen Lange

(Norsk Hydro)

Slip-stream Reclamation Ormen Lange

Atmospheric

boiling


Rich MEG Pre –

Treatment &Storage

Lean MEG

Storage & Injection

MEG

Reconcentration

Low soluble salts

Rich MEG

Feed

Hydrocarbons Water

Reclamation

Vacuum boiling

Particle precipitation

Centrifuges

High soluble saltsTemperature increase

Pressure decrease

Alkalinity controlParticle precipitation

Centrifuges/Settling

tanks




Technology Experience

Decanter Centrifuges

■ Installed and operated on● Asgard B (Norway)

● Shah Deniz (Azerbaijan)

● Britannia Satellites (UK)

● KG-D6 (Reliance - India)

■ High speed rotation – up to 3000g■ Particle removal down to 10

microns

■ Removal of high and low solublesalts

■ Preference for dry product (lessthan 5% moisture content)

■ Low MEG loss

Standard part of the APS MEG Regeneration unit





Disc-stack Centrifuges

■ Installed and operated on

● Ormen Lange (Norway)

■ Testing

● Gorgon

■ Removal of low soluble salts from Lean MEG

● APS independent testing

■ Removal of low soluble salts from Rich MEG■ Effect of entrained condensate on efficiency

■ High centrifugal forces – 5000 to 7000g

■ Remove of particles down to 1micron

■ Preference for clarified liquid phase

■ Small footprint

■ Down stream equipment required to reduce MEG loss

To be installed on the Gorgon Project





Settling Tanks

■ Installed and operated on

● Reliance KG-D6 (India)● Pluto (Australia) – to be commissioned in

2010

■ Gravity settling

■ Remove of particles down to 10microns

■ Secondary treatment required to remove smallerparticles (e.g. Filters)

■ Large footprint (only feasible for onshoreapplications)

■ Stable conditions (i.e. no movement)

■ Down stream equipment required to reduce MEGloss




Future Development

Market Trends

■ Larger MEG Regeneration requirements■ Development of gas fields with high salt content formation water

■ Increase in offshore and FPSO applications

● Limitations on space and power usage




Future Development

■ Solid-Liquid Cyclones

● APS has extensive experience with cyclones■ Oil/water cyclones

■ Sand cyclones

● Solid-liquid separator with no moving parts

● Compact

● Removal of particles down to 10 microns

● On-going research work (University of Bergen)■ Gas Flotation

● Use of micro-bubbles to float particles out of solution

● Patent filed

● Looking for partners to test and qualify technology




Summary

■ Salt removal in MEG Regeneration systems is a challenge

● Can be achieved through good chemistry control & properseparation equipment

■ Use of decanter centrifuges to separate large particles is veryeffective

■ The most effective/compact method for small particle removal is

through the use of disc stack centrifuges■ Settling tanks in combination with downstream polishing methods

can be used as an alternative to disc stack centrifuges, however notconsidered feasible in offshore applications

■ Looking into alternatives to reduce footprint and complexity

● Solid-liquid cyclones● Flotation




Contact Details

Product & Technology Manager

Jon Even Vale

Telephone No: +47 67513655 / mobile +47 97146179

E-mail: [email protected]

Sales Director

Simonetta Brossa HoelTelephone No: +47 67837771 / mobile +47 41400998

E-mail: [email protected]

Technical Contact

Shanta SeereeramTelephone No: +47 67527229

E-mail:[email protected]

mailto:[email protected]









Copyright

Copyright of all published material including photographs, drawings and images in this documentremains vested in Aker Solutions and third party contributors as appropriate. Accordingly, neither the

whole nor any part of this document shall be reproduced in any form nor used in any manner withoutexpress prior permission and applicable acknowledgements. No trademark, copyright or other noticeshall be altered or removed from any reproduction.

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