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Within the PETRONAS MLNG Dua facility, hydraulic

actuators on propane and MCR compressors anti-

surge valves were a continual source of trouble for the MLNG

maintenance team. From October 1995 to December 2000, 12trips were a result of hydraulic actuator failures. Major issues

directly related to the failures included:

n opportunity production loss in excess of $10 million,

n slow opening of valves under trip conditions not meeting

the 1 second stroking speed requirement,

n failure to operate on demand with the risk of machine

damage under surge

npotential loss of lives with the risk of explosion.

These actuators provided inadequate servo control,

demonstrated continual leakage problems, and often delayed

its response during critical operation periods.

A series of malfunctions were also responsible for the lack

of performance. Among these were sticky anti-surge valves,

accessories failure, hydraulic & accumulator pressure failures,

jewel gland leaks and electronic hardware failures.

Because of these problems, PETRONAS approached CCI to

engineer an actuator solution. The challenge for CCIs oil

and gas design engineering team was to design an operator

that could be installed on an existing 24-in (600-mm) valve

without any modications to the valve itself. In addition, the

design was required to have a stroking speed of less than one

second to protect the compressor from surge.

CCIs solution to PETRONAS problem was a fast acting

pneumatic actuator with anti-surge accessories. The

actuator was custom-engineered to interface directly with

the existing valve design. This allowed for a fast retrot andrequired MLNG to make almost no systems modications.

In addition, the one-second actuator stroking time added a

factor of safety against surge that was not available from the

hydraulics.

The trial unit was successfully tested and installed into

the MLNG Dua facility. Within two weeks following

installation, PETRONAS informed CCI that a compressor

had gone into a trip mode. The CCI actuator had

responded immediately; exactly as designed. Because of thesuccess in this application PETRONAS has now retrotted

21 hydraulic actuators in their MLNG Dua facility with the

CCI pneumatic system solution.

The end result is zero failures to date, with 100% reliability.

Zero Failures, 100% Reliability:

CCIs Alternative to Hydraulics for an

Anti-Surge Control Solution

PerformanceMATTERS

559 | 02/03 w 2003 CCI w DRAG is a registered trademark of CCI.