anti-surging control system

8/10/2019 Anti-Surging Control System

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SURGING

Compressor surge is an unstable flow pattern in a compressor where the total flow athe airfoil alternately stops, flows backwards, and then flows forward.

Surge is associated with a sudden drop in delivery pressure and with violent aerody

pulsation which is transmitted throughout the whole machine.


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REASONS OF SURGING

Poor matching of the compressor to the system requirements.

Inappropriate compressor design.

Inadequate anti-surge control system.

Unfavorable arrangement of piping and process components of the system, which o

magnify surge.


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EFFECTS OF SURGING

Rapid flow and pressure oscillation causes process in stability

Rising temp. inside compressor

Mechanical damage

Tripping of compressor

Changes in the production rate


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IDENTIFICATION OF SURGING

SURGING CAN BE CLEARLY IDENTIFIED BY FOLLOWING SYMPTOMS.

HEAVY THUMPING NOISES IN COMPRESSOR.

EXCESSIVE VIBRATIONS.

RAPID FLUCTUATION IN FLOW.

RAPID FLUCTUATION IN DISCHARGE PRESSURE.


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COMPRESSOR OPER TING CURVE

Pressure

Flow rate

1

2

3 .

MAX.STABLE COMP. FLOW POINT

MIN.STABLE FLOW POINT

WHEN FLOW AT I/L REACHES SONICVEL.NO FURTHER FLOW INCREASE

IS POSSIBLE

DUE TO LOW FLOW ,IT NO LONGER

CAN ADHERE TO SUC. SIDE OF BLADE

SO STALLING OF FLOW


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AB

C D

Pressure

Flow Rate

Flow

which

pressu

resista

discha

from D

SURG CYCLE

o

As flow decreases continuously

to point Acomp loses its

ability to make pressure hence

Ps drops i.e. Pd >Ps and flow

reverses Compressor Operating

point move fromA

toB

. Resultof flow reversal Is that pressure

goes down pressure goes down

at discharge and curve move

from Bto C.

System pressure is going down

comp is again able to developsPressure comp jumps back to

performance curve to Dforward

flow established


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ANTI-SURGE SYSTEM

Anti surge controller protect the compressor against surge by opening recycle valve. this resistance (back press) and system will again come in normal situation.

Recycle the streams icture

Vent the discharge stream

Performance controller


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CHARACTERISTIC CURVE

Operating line

Surge control line

Recycle trip line

Surge limit line

Safety online


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SURGE CONTROL LINE


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RECYCLE TRIP LINE


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SURGE LIMIT LINE


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SAFETY ONLINE


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PICTURE


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AIR EXTRACTION SYSTEM


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SECURITIES ON ANTI SURGE SYSTE


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ANTI SURGE OF GT-601/602


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ANTI SURGE ON GT-603


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ANTI-SURGE ON GT-604


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ANTI SURGE ON C-702


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ANTI SURGE ON K-2502


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MODIFICATIONS IN AS SYSTEM OF G


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RECOMMENDATIONS


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anti-surging control system

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