kontroll ventiler

Bjørge Solberg & Andersen

KONTROLL VENTILER

• JAN O HJETLAND


Fag disipliner

• Prosess• Material• Instrument• ”Piping”• Maling• Innkjøp• Produksjons oppfølging


Sete ventil (Globe)

Kule ventil (Bal)

Sving ventil (Butterfly)

Hvilken type kontroll ventiler har vi


Hva er en kontroll ventil

En kontroll ventil er arbeideren i en prosess lup


•


BUTTERFLY


Ball


Globe


CAGE

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Separator Level Control

LC

LC

Oil Water

Oil

Gas

Oil level Control valve Water level Control valve

Gas outletCrude Inlet from well head


Ventildimensjonering og valg - fremgangsmåte

1) Beregning av ventilstørrelse 2) Beregning av støy / andre forhold

3) Valg av ventiltype - gjenta fra 1 4) Valg av materialer / pakkboks

5) Beregning og valg av aktuator 6) Tilleggsutstyr / endelig beskrivelse

Gjenta beregningene med relevante ventildata


KURVE


Beregne ventilstørrelse - bakgrunn

• Har stort sett vært basert på leverandørenes egne standarder / metoder

• Standardiseringsarbeide har pågått siden tidlig 1960

• ISA etablerte en komite i 1967 som skulle utvikle og distribuere standard ligningssett - ble til en “American National Standard”

• IEC benyttet ISAarbeidet som basis for å formulere internasjonale standarder

• ISA og IEC standardene er harmonisert, med noen få unntak (nomenklatur)

• ANSI / ISA Standard betegnes S75.01

• IEC standard har betegnelsen 534-2-1 og 534-2-2 (inkompressible og kompressible medier) Disse standardene inneholder også metodikk for støyberegninger

1) Beregning av ventilstørrelse 2) Beregning av støy / andre forhold

3) Valg av ventiltype - gjenta fra 1 4) Valg av materialer / pakkboks

5) Beregning og valg av aktuator6) Tilleggsutstyr / endelig beskrivelse


Støy i reguleringsventiler

• Støy i reguleringsventiler er en stor bidragsyter til anleggets totale bakgrunnsstøy

• Myndighets krav blir stadig strengere

• Støykilder i et anlegg er vanskelige å identifisere, p.g.a. mange forskjellige kilder, refleksjoner, forplantning av støy etc.

• Brukere som ser bort fra støykravene er eksponert for unødvendige belastninger

• Kontraktører som garanterer å møte spesifikasjoner for støy er eksponert for potensielle erstatningssaker / kostnader ved korreksjoner


Aerodynamiske støykilder


Linje-kilde

R

LpA = F + 10 Log 1 + rR + r

Tverrsnitt av rør For hver dobling av avstand, tapes 3 dBa


Noise Trims - Whisper I

• Splits flow into small rectangular passages

• Increases Peak Frequency

• Complimentary body design

• Most effective dP/P1 <0.6

• Up to 20 dB attenuation


Whisper III

• Flow passes through small holes– Level 3 Uses 1.6 mm dia– Level 1 Uses 3.2 mm dia– 6 dBA difference

• Increases frequency• Complimentary body design• Jet independence• Up to 30 dB attenuation


Whisper IIIC/d = 3.4

dP/P1< 0.99

C/d = 2.7

dP/P1 < 0.75

C/d = 2.0

dP/P1 < 0.6 Air Flow

P1

P2

B3

1.6 mm

C3

1.6 mm

A3

1.6 mm


WhisperFlo

• Staged Reduction of Pressure• Shift Frequency Spectrum Higher• Unique Passage Shape• Jet Independence• Manages Velocity Using an

Expanding Area Principle• Complimentary Body Design• Up to 40 dB attenuation


WhisperFlo Flow Passage

Inlet

Outlet


Lyddemper


Reduksjon av støy

StandardSchedule40 Pipe

110 dBA

Schedule80 Pipe

106 dBA

AcousticalInsulation(2-inches)

96 dBA


110 dBA

Silencer orDiffuser

85 dBA


85 dBA

path

SourceTreatment

PathTreatments

NoiseAttenuatingValve Trim

AttenuationDepends OnTrim Design


• Globe ventil med diffuser

Begrense støy-generering


VESKE

• FLASING• CAVITATION


Pressure

Velocity

Liquid Flow through an Orifice

Vena Contracta

Lowest Pressure

Highest Velocity


Pressure

Cavitation

Vena Contracta

VapourPressure

Vapour Bubbles Form Vapour Bubbles Collapse


High Recovery Valves (Km= Fl2= 0.5) Line of sight valves; Butterfly, Ball

Pressure

Pressure

Low Recovery Valves (Km = Fl2=0.8)Globe valves


Cavitation Damage


Cavitation - Path Treatment

• Cover exposed areas with resistant material– 316 Sst < 18 HRC– 416 Sst (Std trim material) 38 HRC min– 440C 56 HRC– Alloy 6 (Stellite) 36 to 44 HRC– Ceramic– Tungsten Carbide


Cavitation - Path TreatmentCavitrol III 1 Stage• Flow down• Holes directly opposing

– Keeps any cavitation in centre of cage away from surfaces


Cavitation - Source Treatment• Treating the cause of cavitation

– Use valve trim that avoids cavitation• Low recovery valve

– High FL2( KM)

– Change from rotary valve to globe

PressureP1

PV

P2

High Recovery Valve (Km) FL2 = 0.5

Cavitation

Low Recovery Valve (Km)FL2 = 0.85

No Cavitation


Controllingorifice

Hole shape

High Capacity

Low Recovery

The hole is designed to maximize flow without flow separation from the wall,and with enough recoveryvolume for the fluid from the previous orifice .

Pilot hole and recovery volume

flow

Bjørge Solberg & AndersenHole Design - Control Flow Separation

Thin Plate

Low Capacity

Low Recovery

Thick Plate

High Capacity

High Recovery

Cavitrol Hole

High Capacity

Low Recovery

Any cavitation that does occur is outside cage wall


Staged Pressure Drop

P1

P2

PV

1st Stage 2nd Stage 3rd Stage

Standard Trim

Staged Cavitrol Trim

Note the uneven pressure drops. The first stage takes the majority of the drop so

the last stage takes very little and can control Pvc very

close to Pv.


CAVITROL IV

NOSIGNIFICANTPRESSURE DROP

MORE THAN90% OF THEPRESSUREDROP

VERY LOWINLETPRESSURETO FINALSTAGE

•CAV4 with Cavitrol IV Trim

•Trim can take pressure drops up to 448 Bar

•Protected seating surface eliminates significant pressure drop across seating surfaces

•Trim can be used in other globe or angle valves

•Staged clearance flows


MINI CAV4 TRIM

AVAILABLE IN 2” CLASS 1500 AND 2” CLASS 2500 DESIGN EHS VALVES

1” DIAMETER PORT, 3/4” TVL

Cv RANGE - .1 TO 2.9

SAME LIMITS AND FEATURES AS STANDARD CAV4

USED FOR METHANOL LETDOWN

CAV4CAV4 Special Products Group


Velocity - Cavitrol

Outlet Stage:Average velocity = 45 ft/secPeak velocity - 57 ft/sec

Second stage velocity lower than First stage


Separator Level Control

LC

LC

Oil Water

Oil

Gas

Oil level Control valve Water level Control valve

Gas outletCrude Inlet from well head


Challenges of these applications

• Cavitation– High pressure drops

• Erosion – High pressure drops– Sand and other particles

• Corrosion– Sour conditions– Chloride stress cracking

Bjørge Solberg & AndersenProduced Water/Water Injection Valve Issues

• High pressure drop – Can lead to damaging cavitation and

erosion• Solid particulate can lead to plugging of

conventional severe service trim• Tight shutoff required

– Protects the valve from low flow damage when in the closed position

• Possible corrosion issues– Issues with stress corrosion cracking

need to be addressed• Depends upon H2S and chloride

concentration

Typical stacked disc trim

Bjørge Solberg & Andersen Erosion

• Hard surfaces– decreases the amount or speed of damage– Alloy 6 – 440C – Tungsten Carbide– Ceramics

Increasing

erosion resistance


DST Flow Down

W678-1


Rotary Actuator


HOOK UP

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DVC6000


E.SEAL

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