GE Energy

System 1* Software

UsinG PV CUrVEs to DiaGnosE a rECiP ValVE ProblEmThe single most important measurement for condition monitoring of reciprocating compressors is cylinder pressure. Armed with accurate cylinder pressure at each point in the piston’s stroke, a Pressure-Volume (PV) curve can be constructed, which provides indispensable information on the machine’s health.

Problemthree reciprocating compressors provide compressed hydrogen for the catalytic cracker in a major Us refinery. in order for the unit to run at full output, all three compressors must run simultaneously. the loss of one machine results in a 20% loss in plant production.

SoluTiona 3500 series monitoring system provides alarms on high vibration and transmits all parameters to system 1* Condition monitoring and Diagnostics software for storage and display. Parameters monitored include cylinder pressure (displayed as pressure vs. volume, or PV), cylinder valve temperature, main bearing temperature, suction and discharge temperatures, frame velocity, crosshead acceleration, piston rod vibration, and rod position. important parameters derived from these measurements include rod load (compression and tension), degrees of reversal, peak cylinder pressure, discharge pressure, minimum cylinder pressure, suction pressure, and compression ratio.

PAybAckan increase in vibration in the crosshead vibration on the low-purity, third-stage cylinder triggered an alarm in the 3500 monitor which alerted the plant’s rotating equipment engineering group. through cylinder pressure information provided online by system 1, engineering was able to assess the stresses that the malfunction induced upon the recipro-cating compressor and, based upon these stresses, decide when to shut down the machine so that further damage did not occur. this resulted in a shorter outage, lower maintenance cost, and the prevention of a major failure. as a 20% reduction in production results from having one machine down for maintenance, a large part of the savings can be attributed to the decrease in unscheduled maintenance downtime.

benefiTS• reduced need for “just in case” inspections through accurate, real time machinery

information that shows actual mechanical stresses and conditions.

• Shorter, more efficient outages by knowing what needs attention and what doesn’t along with what parts and skills are needed.

• improved machinery reliability through the ability to correlate process conditions with mechanical conditions and make necessary operating adjustments to prolong asset life.

3500 Series monitoring System

As seen in

learn more by reading the feature-length case study article in orbit magazine Vol. 24, no. 1, 2004 at www.orbit-magazine.com

www.ge-energy.com/ocsuccess

oil &

Gas – Petroleum

refining

CUstomEr sUCCEss story bEntly nEVaDa* assEt ConDition monitorinG

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