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  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Separation devices for the gas industry : TEG contactor case study, New ZealandAbhilash Menon , Patrick Lura & Gert Konijn

    Sulzer Chemtech

    Moving Ahead

    Sulzer Chemtech, Winterthur, Switzerland Shell Global Solutions International, Amsterdam, the Netherlands

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Outline

    Mist elimination technology in G/L separation

    fundamentals

    typical mist elimination devices

    Applications in NG dehydration

    Case study : TEG contactor, New Zealand

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Mechanisms of droplet collection

    Obstacle

    e.g. Fiber

    FLOWVelocity (V)

    < 0.5 m

    > 100 m

    > 3 m

    ~ 1 m

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Wire mesh mist eliminators

    moderate gas handling and liquid

    load capacity

    very high separation efficiencies

    prone to fouling with high liq load

    low pressure dropGas with free liquid

    Gas without free liquid

    by gravity by gravity

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Vane-pack mist eliminator

    Horizontal gas flowVertical gas flow

    Gas

    Gas droplet inertia, centrifugalforce, impingement, g

    high gas handling

    and liquid load capacity

    high separation efficiency

    suitable for high viscosity

    low pressure drop

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Primary gas outlet

    Secondary outlets

    (from slits)

    Swirl part

    Separation part

    Secondary gas

    Liquids

    Bottom plate

    Top plate

    Separation swirltube

    inertial, centrifugal force, g

    very high gas handling and liquid

    load capacity

    high separation efficiency

    prone to fouling with high viscosity

    moderate pressure drop

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Separation equipment Application

    Sulzer KnitMesh

    mist eliminatorsSulzer Mellachevron

    vane packs

    Shell Swirltube

    axial cyclones

    VANE MIST ELIMINATORS

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Natural Gas Dehydration

    Flash

    Tank

    Glycol Filter

    Glycol

    Cooler Heat

    Exch.

    Storage Tank

    Stripping column

    Heater

    Heater

    Heat Exchange

    Section

    Rectification

    section

    Condenser

    Water vapors +

    Hydrocarbon gas

    Regenerator

    Stripping

    Gas

    Lean TEG

    Wet Gas

    Dehydrated

    Gas

    Rich TEG

    Water +

    Condensate

    Contactor

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Internals

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Original DesignBubble Cap trays and

    KnitMesh mist eliminator

    100 % capacity

    1.5 F-Factor

    190 % capacity

    >20 % more efficiency

    2.9 F-Factor

    First Revamp

    Mellapak and KnitMesh mist eliminator

    TEG

    NG

    400 % capacity

    20 % more efficiency

    6.0 F-Factor

    Third Revamp

    Shell Swirl TubeTrays

    TEG

    NG

    Glycol Contactor - Revamps

    Second Revamp

    MellapakPlus & Swirldeck

    TEG

    NG

    300 % capacity

    >20 % more efficiency

    Max. 4.5 F-Factor

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Glycol losses

    Glycol losses with a secondary demisting device well selected according to the gas loads

    0

    0.015

    0.030

    0.045

    0.060

    0.075

    0.090

    0.105

    0.110

    0.125

    0.140

    0.155

    0.170

    0.185

    0.200

    0.215

    0.230

    0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6

    F-Factor

    Mellapak

    MellapakPlus

    Bubble Cap Trays

    US

    ga

    l/M

    Ms

    cf

    0.1 USgal/MMscf

    Swirl-tube trays

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Case Study : TEG Contactor, New Zealand

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    TEG Contactor

    first supplied by Sulzer in 2005column brought online in Oct.2006

    top de-entrainment device: Knitmesh 9797 mesh pad

    top Liquid distributor

    packing : Mellapak structured packing

    chimney tray collector

    integral scrubber: rectangular vertical vane-pack (non-Sulzer hardware)

    inlet device: Schoepentoeter

    Vane pack

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Reported Problems

    Problemexcessive glycol losses > 20 times expected losses even at 60% throughput. 3% of overall TEG to column was lost

    required glycol losses: 13.4 litres (TEG)/MMscm (gas)Sulzer guarantee (with Knitmesh 9797 mesh pad): 6.7 litres/ MMscm

    Information received lost glycol traced to the column sump samples taken downstream of the TEG Contactor gas outlet showed little

    presence of TEG dewpoint specifications met pressure drop across packing: 0.8 to 1.2 kPa so foaming in packing

    unlikely cause of problems no separate inlet separator upstream of TEG Contactor prolonged skimming in chimney tray showed presence of HC liquid and

    foam

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Actions

    1st reaction

    vane-pack wrongly installed or damaged ?

    Course of action / Findings

    Inspection carried out on column internals (Nov.06)

    No damage reported. Column is clean and internals

    are correctly fitted. No damage to filter or gaskets,

    etc

    Chimney tray leak tested twice and confirmed to be

    leak tight

    Drainpipes from vane-pack extended to below liquid

    level (this did not solve the problem)

    Vane-pack detail

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Operating conditions far away from

    design

    Factor > 70 higher !!

    Factor ~ 7 higher !!

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Possible reasons for high glycol losses

    Vane-packs not advisable under such operating

    conditions

    high pressure : 66 barglow surface tension : gas easily entrains the HC liquidvery high liquid loads : far away from design

    conditions separation efficiency for vane-packs (HC systems)

    drastically reduces (< 90%) at high P

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    What could be happening

    Liquid entrainment is much higherhigh levels of liquid HC in chimney trayfoamingTEG dissolution and carry-down intocolumn sump

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Findings

    Significantly more free liquid HC was present in the feed

    compared to original design conditions

    Flow Parameter at contactor inlet based on new conditions = 0.014

    Flow Parameter at the vane-pack based on new conditions = 0.002 (

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Proposed revamp

    Replace vane-pack demister with :

    pre-conditioner mist-mat :

    Knitmesh 9797 modelhigh performance Swirl Tubes :

    better g/l separation

    Gas with fine

    mist

    Mesh pad

    operates at

    velocity beyond

    re-entrainment

    point

    Most captured

    mist is re-

    entrained as

    large droplets

    Mist free gas

    Mellachevron

    capture large

    droplets

    Captured liquid

    drains

    No gap in some cases

    Proposed changes for chimney tray:

    few risers to be blinded off to minimize splashing of free liquid into the risers

    all riser hats to protrude downwards to cover the riser opening

    Inlet device: No change: existing Schoepentoeter to

    be re-used

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Successful revamp

    Nov.2006: decision to replace vane-pack by KM 9797 mist-

    mat & Swirl-deck

    Feb.2007: New separator installed. Installation supervised

    by Sulzer

    March 2007: Revamp has been successful

    customer reports TEG losses problem solved entrainment from previously installed vane-pack section

    significantly reduced and brought within spec limitsTEG losses reduced from 480 l/MMm3 to 6.7 l/MMm3

    internal skim showed no condensate build up

    no foaming observed

    no TEG detected in column sump

  • Sulzer Chemtech

    MeA, PERS 5, Nice / April 01-03, 2008

    Thank you for your attention !

    Sulzer Chemtech

    Moving Ahead

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