Case Study: Failure Analysis of a Reciprocating Compressor

Arslan Aslam, Senior Rotating Equipment Engineer, Saudi Aramco Total Oil Refining and Petrochemical Company (SATORP)

Description

SATORP is a Refinery and Petrochemical complex processing 450,000 barrel per day of Arabian Heavy Crude Oil and producing the Gasoline, JET, Diesel, LPG, Benzene, Paraxylene, Propylene, Coke and sulfur.

In one of the critical units, a standalone KOBELCO double acting, non-lubricated two cylinders, motor driven, natural gas (NG) feed reciprocating compressor failed on operational parameters upset however, machine did not trip on any protection and remained in service for four hours before its forced shutdown as per reliability engineer recommendations.

Emergency Corrective Maintenance on the compressor resulted in major findings as;
– Broken Piston Rod with severe rubbing.
– Broken Head End Rider Ring.
– Heavily rubbed Liner and Piston assembly.
– Heavily rubbed Stuffing Box on packing cups with Piston Rod.

After detailed failure analysis, it was concluded that piston rod was broken after metallic rubbing of rod with stuffing box cups. Rubbing in the packing cups was caused by broken rider ring, high rod run out, misalignment between cylinder – frame extension. The rod run out and packing rub remained undetected due to faulty rod drop sensor and inadequate stuffing box temperatures monitoring. Machine did not trip on any protection as the cross head vibration trip was removed, only alarms in place, years ago due to spurious incidents that lead to unit shutdown.

The subject case study intends to showcase detailed failure analysis and importance of machine condition monitoring, precision maintnence and equipment reliability review during design phase. Moreover, practical lessons learnt and areas of improvement are also highlighted so that similar high finanacial impact incidents would be avoided.

Takeaways
– Condition Monitoring, a must for Critical Equipment
– Precision Maintenance
– Detail Design review – Improvement of Inherent Equipment Reliability

Bio

As a Senior Rotating Equipment Engineer in Saudi Aramco Total Oil Refining and Petrochemical Company (SATORP),KSA, I am excelling being responsible, innovative and ambitious in achieving high targets with safety and quality. I have more than 12 years’ experience of core Rotating Equipment, Machinery Diagnostics, Reliability Enhancement & Plant Maintenance mainly in Refinery and Petrochemical sector.

Key area of expertise includes;
– Safe, uninterrupted and reliable operations of plant critical equipments
– Vibration analysis thru BN-Adre, System-1 and CSI.
– Condition Monitoring thru Lube Oil analysis, process parameters monitoring, Thermography etc.
– Failure Root Cause Analysis (RCA) thru various techniques like TapRoot, Fish bone, Fault tree, 5 why etc.
– Development and implementation of AIM services by utilizing techniques i.e. RCM, RAM, FMECA, RCA, Optimized PM strategies and other industry accepted practices.
– Hands on experience of APM/CMMS software like Meridium, Isograph, SAP and Oracle.