Case Study: Failure Analysis through Vibration Monitoring of Hydrogen Compressor

Arslan Aslam , Rotating Equipment Engineer, Saudi International Petrochemicals


International Diol Company (IDC), an affiliate of SIPCHEM, KSA has a unit consist of an induction Motor (2050 kW, 3575 RPM, Mfr: ABB) driving a single stage integral gear centrifugal compressor (16,600 RPM, Mfr: Atlas Copco) for handling Hydrogen gas. Unit is monitored by BN3500 Vibration system with paired XY probes installed radially at Motor and compressor bearings. Vibration data were collected by using ADRE 408.

At startup maximum observed vibration levels at motor DE X probe was 75μm and found that gradually increased to 100μm within 30 minutes with increase in compressor load. Further continuous operation up to one-month, maximum observed change in vibration levels was from 120μm~150μm at Motor DE during steady state condition which was at danger levels. Meanwhile, integral gear compressor vibration levels were stable.

Detailed analysis revealed a fluctuation of 10~20μm of synchronous instability in Motor DE. It was also observed that motor DE show a slight (4um) cyclic movement of shaft center line inside the bearing during steady state. Full spectrum waterfall plot and spectrum plot show predominant 1X component with forward precession. Slight 2X component (8um) were also observed at steady state. Recorded orbit plot shows highly elliptical pattern at both DE and NDE side with major axis along X probe. Elliptical pattern suggests some preload force acting on the shaft which restricts the free movement of rotor.

After vibration analysis, it was concluded that continuous change in alignment was due to preload condition, may be caused by abnormal pipe stress which connected to compressor or change in motor soft foot condition on motor foundation bolts. Based on condition monitoring report, compressor alignment inspection and piping stress analysis was planned. During precision maintenance activities it was observed that compressor suction/discharge piping was 12.8/9.2 mm misaligned.


1. Reduced lost production time.
2. Reduces equipment maintenance cost.
3. Precision maintenance.

Bio - Arslan Aslam

Working as a Reliability Engineer (Rotating Equipment) in Saudi International Petrochemicals Company (SIPCHEM),KSA, i am an accomplished and self-driven mechanical engineer (CMRP) with the ability to lead multi-cultural teams. I have more than 08 years’ experience of core Rotating Equipment, Vibration Analysis, Machinery Diagnostics, Reliability Enhancement & Plant Maintenance mainly in Fertilizer and Petrochemical sector of various countries like KSA, UAE and Pakistan. Experience of renown vendors like BHGE, Nuovo Pignone, Sundyne, MAN Turbo, Dresser-Rand, Ingersoll Rand, Pacific, Burkhart, Elliot, Worthington, Kobelco, Flowserve etc. Key area of expertise includes; – Safe, uninterrupted and reliable operations of plant machinery which includes Process Compressors (Centrifugal / Reciprocating) & its driver Steam Turbines, Power generation Gas turbines, Fans, pumps (centrifugal & positive displacement) and Blowers.  – Vibration analysis thru BN-Adre, System-1 and CSI. – Condition Monitoring thru Lube Oil analysis, process parameters monitoring, Thermography etc. – Field Balancing (Single plane,Dual Plane) – Failure Root Cause Analysis (RCA) thru various techniques like 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.