Improving Reliability On A Centrifugal Compressor Experiencing Frequent Bearing Failures

Abstract

A 1957 vintage multi-stage centrifugal compressor, critical in a refrigeration process, had a history of poor reliability and LP stage bearing failures. Around 1995 the HP casing had been replaced and upgraded. In early 2010, the compressor suffered a major failure, including rubbing internally due to a thrust bearing failure, and damages to the shaft and drive end coupling. A new rotor and new gear type coupling were installed, both matching the original design. Since the start up after this, the thrust and journal bearings had failed approximately once per month greatly reducing the reliability of the compressor and plant profitability. To eliminate this problem, it was decided to change the coupling and to redesign and replace the bearings from the LP compressor, within the very limited spacing of the original bearing assemblies.