zz antisurge r0

8/19/2019 ZZ Antisurge r0

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Speedtronic MKVIe Control Panel Trai

Centrifugal Compressor Antisurge


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OverviewPRESSURE

TRANSMITTER

ANTISURGE VALVE

COMPRESSOR

FT PT PT

ANTISURGECONTROL

FLOWTRANSMITTER

PRESSURE

TRANSMITTER

Ps = Suction Pressure

Pd = Discharg

Qin = Inlet Flow Rate

Compressor Ratio

CPR = Pd


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Performance Curves Macontin(

Minimumoperating speed

(MOS)

C o m p r e s s o r

P r e s s u r e R a t i o ( C P R )

PerformanceCompressor Curve

65%

80%

90%

98%100%

105%

Inlet Flow Rate (Qin)

Compressor Speed


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Performance Curves External resistanc

Operatingpoint

65%

80%

90%

98

The actual operating point is unique and itis always the intersection between thecompressor curve at the given speed andthe plant resistance curve.

C o m p r e s s o r P r e s s u r e R a t i o ( C P R )



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Performance Curves

Surge LimitLine

Choking Area65%

80%

90%

98%

100%

105%

Operating range

C o m p r e s s o r P r e s s u r e R a t i o ( C P R )



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Choking Area65%80%

90%

98%100%

105%

Choke rapresents the right limit of pecurve.

The pressure decrease and the InletFlow remain the same.

Choking

C o m p r e s s o r P r e s s u r e R a t i o ( C

P R )


Rapid decrease in performances andefficiency.

The Choking isn’t dangerous for themachine.


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Surge is the left limit of performance curve, on the left of this line the compressor operaunstable condition;

All surge points, defined for different speeds represent the Surge Limit Line;

Surge LimitLine

65%

80%90%

98%

105%

Surge

C

o m p r e s s o r P r e s s u r e

R

a t i o ( C P R )


100%


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P2

P1

P2 > P1

Flow inside the impeller

Axial thrust

Surge


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P2

P1

Flow inside the impeller

Axial thrust

P1 > P2

Surge


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Surge Consequences

• Unstable flow and pressure

• Damage percentage increases with severity to seals, bearings, impellers and shaft

• Increased seal clearances and leakage

• Lower efficiency

• Reduced compressor life

Surge

TRIP

AntisurgeSystem


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The Antisurge System is composed by:

Antisurge Valve

Instrumentation:

Flow indicator trasmitter

Pressure indicator trasmitter

Electronic controller

Antisurge System


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The opening of the Antisurge Valve increases the suction flow moving the operating point aspeed.

PRESSURETRANSMITTER

ANTISURGE VALVE

COMPRESSOR

FT PT

ANTISURGECONTROL

FLOWTRANSMITTER PRESSURETRANSMITTER

Antisurge System

Surg

C o m p r e s s o r P r e s s u r e

R a t i o ( C P R )


PT


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65%

80%

90%

98%100%

105%

Surge Control

Line

Surge Limit Line

Surge

Protection Line

Safety CorrectionLine

Antisurge System

Ope4% pe

Ope10% p

Fully O


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The Hot Gas Bypass Valve is a Safety ON-OFF Valve opened during the TRIP to obtain a fastof the GAS.

PRESSURETRANSMITTER

ANTISURGE VALVE

COMPRESSOR

FT PT

ANTISURGECONTROL

FLOWTRANSMITTER

PRESSURETRANSMITTER

Hot Gas Bypass

COOLER

PT


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zz antisurge r0

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