Condition Monitoring, Troubleshooting and Reliability in Rotating Machinery

16Failure Analysis & Design Evaluation of a 500 KW Regeneration Gas Blower

By Abdulrahman Alkhowaiter

Introduction

The centrifugal single stage gas blower analyzed in this chapter is a highly critical unspared centrifugal blower for the CCR Reformer producing gasoline at a new refinery commissioned in 1999 (Figure 16.1). The blower is located high up on a seventh floor platform close to the reactor with difficult access and experiences high operating temperatures of 900 ^oF. The blower, which is directly driven by a 500 KW motor, operates at 1800 to 3600 RPM. During review of past failures and historical problems with this machine, the data revealed that this machine has operated unreliably for many years, resulting in site maintenance expenses exceeding USD 1.70 MM. The average blower Mean Time Between Failures (MTBF) from 1999 to 2013 was only 6 months, which was deemed to be completely unacceptable. The reliable lifetime between failures for such a machine in this service should be 4.0 years.

Historical blower failures include:

1. Early bearing failures of 4500 hrs. average life compared to required 40,000 hrs.
2. Frequent overheating of bearings.
3. Premature shaft seal failures with gas leakage and shaft sleeve damage at seal zone.
4. High blower vibration and sometimes noise due to rubbing of parts.

Present Situation:

The blower failed in March 2014 and the spare machine was sent to a local approved shop for overhaul repair. Refinery maintenance clarified that the blower has had ...