Bjørge Solberg & Andersen
KONTROLL VENTILER
• JAN O HJETLAND
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Fag disipliner
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Prosess
Material
Instrument
”Piping”
Maling
Innkjøp
Produksjons oppfølging
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Hvilken type kontroll ventiler har vi
Sete ventil (Globe)
Kule ventil (Bal)
Sving ventil (Butterfly)
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Hva er en kontroll ventil
En kontroll ventil er arbeideren i en prosess lup
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BUTTERFLY
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Ball
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Globe
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CAGE
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Separator Level Control
Gas outlet
Crude Inlet
from well
head
Gas
Oil
LC
LC
Oil
Oil level Control valve
Water
Water level Control valve
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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
Gjenta beregningene med relevante ventildata
5) Beregning og valg av aktuator
6) Tilleggsutstyr / endelig beskrivelse
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KURVE
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Beregne ventilstørrelse - bakgrunn
1) Beregning av ventilstørrelse
2) Beregning av støy / andre forhold
3) Valg av ventiltype - gjenta
4) Valg
fra 1av materialer / pakkboks
6) Tilleggsutstyr / endelig beskrivelse
5) Beregning og valg av aktuator
• 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
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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
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Aerodynamiske støykilder
Expansion
Area
Obstructions
To Flow
turb
Changes In
Flow Direction
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Linje-kilde
Tverrsnitt av rør
For hver dobling av avstand,
tapes 3 dBa
R
LpA = F + 10 Log
1+r
R+r
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Noise Trims - Whisper I
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Splits flow into small rectangular
passages
Increases Peak Frequency
Complimentary body design
Most effective dP/P1 <0.6
Up to 20 dB attenuation
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Whisper III
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Flow passes through small
holes
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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
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Whisper III
C3
C/d = 3.4
1.6 mm
B3
dP/P1< 0.99
C/d = 2.7
1.6 mm
dP/P1 < 0.75
P2
P1
A3
C/d = 2.0
1.6 mm
dP/P1 < 0.6
Air Flow
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WhisperFlo
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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
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WhisperFlo Flow Passage
Outlet
Inlet
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Lyddemper
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Reduksjon av støy
Source
Treatment
Path
Treatments
Noise
Attenuating
Valve Trim
Standard
Schedule
40 Pipe
Schedule
80 Pipe
Acoustical Standard Silencer or Standard
Insulation Schedule Diffuser
Schedule
(2-inches) 40 Pipe
40 Pipe
Attenuation
Depends On
Trim Design
110 dBA
106 dBA
96 dBA
path
110 dBA
85 dBA
85 dBA
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Begrense støy-generering
• Globe ventil med diffuser
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VESKE
• FLASING
• CAVITATION
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Liquid
Flow through an Orifice
Vena Contracta
Pressure
Highest Velocity
Velocity
Lowest Pressure
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Cavitation
Vena Contracta
Pressure
Vapour
Pressure
Vapour Bubbles Form
Vapour Bubbles Collapse
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Pressure
High Recovery Valves (Km= Fl2= 0.5)
Line of sight valves;
Butterfly, Ball
Pressure
Low Recovery Valves (Km = Fl2=0.8)
Globe valves
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Cavitation Damage
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Cavitation - Path Treatment
• Cover exposed areas with resistant material
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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
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Cavitation - Path Treatment
• Cover exposed areas with resistant material
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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
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Cavitation - Path Treatment
Cavitrol III 1 Stage
• Flow down
• Holes directly opposing
– Keeps any cavitation in centre
of cage away from surfaces
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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
Pressure
Low Recovery Valve (Km)FL2 = 0.85
No Cavitation
P1
P2
PV
High Recovery Valve (Km) FL2 = 0.5
Cavitation
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Hole shape
The hole is designed to
maximize flow without flow
separation from the wall,
and with enough recovery
volume for the fluid
from the previous orifice .
Pilot hole and
recovery volume
flow
Controlling
orifice
High Capacity
Low Recovery
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Hole Design - Control Flow Separation
Any cavitation that does occur is
outside cage wall
Thin Plate
Low Capacity
Low Recovery
Thick Plate
High Capacity
High Recovery
Cavitrol Hole
High Capacity
Low Recovery
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Staged Pressure Drop
1st Stage 2nd Stage 3rd Stage
Standard Trim
Staged Cavitrol Trim
P1
PV
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.
P2
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CAVITROL IV
•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
NO
SIGNIFICANT
PRESSURE
DROP
MORE THAN
90% OF THE
PRESSURE
DROP
•Staged clearance flows
VERY LOW
INLET
PRESSURE
TO FINAL
STAGE
Bjørge Solberg & Andersen
CAV4
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
Special Products Group
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Velocity - Cavitrol
Outlet Stage:
Average velocity = 45 ft/sec
Peak velocity - 57 ft/sec
Second stage velocity lower than First stage
Bjørge Solberg & Andersen
Separator Level Control
Gas outlet
Crude Inlet
from well
head
Gas
Oil
LC
LC
Oil
Oil level Control valve
Water
Water level Control valve
Bjørge Solberg & Andersen
Challenges of these applications
• Cavitation
– High pressure drops
• Erosion
– High pressure drops
– Sand and other particles
• Corrosion
– Sour conditions
– Chloride stress cracking
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Produced Water/Water Injection Valve Issues
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High pressure drop
– Can lead to damaging cavitation and
erosion
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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
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Possible corrosion issues
– Issues with stress corrosion cracking
need to be addressed
• Depends upon H2S and chloride
concentration
Typical stacked disc trim
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Erosion
• Hard surfaces
– decreases the amount or speed of damage
– Alloy 6
– 440C
– Tungsten Carbide
– Ceramics
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DST Flow Down
W678-1
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Rotary Actuator
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HOOK UP
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DVC6000
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E.SEAL