Close

Lube oil in compression chamber

NEA horizontal reciprocating compressor

Machine data

NEA (Neumann Esser) horizontal reciprocating compressor with 4 throws. 1 stage in Natural gas service. The Pressure for Inlet is 33 bar (479 psi) for Outlet 75 bar (1088 psi).

NEA horizontal reciprocating compressor

Used Monitoring Software Modules of PROGNOST®-NT

  • Machine Protection
  • Early Failure Detection
  • Wear Monitoring
  • Performance Optimization
  • Process Data Integration

Sequence of events

PROGNOST Systems received a call from the customer. The compressor was shut down by the PROGNOST system shortly after start up. This was a result of protection limit violations on two measuring points. In detail the shutdown was triggered by increased vibrations at the crosshead guides 3 and 4, this affected segment 20 of crosshead slide (CHS) 3 and segment 19 of the CHS 4.

Vibration plots of two the affected crosshead slides three seconds prior shutdown

Root cause analyses

  • Since there were only high vibrations in the area of the Bottom Dead Center (BDC), the possible cause for the shutdown was lube oil from the packing in the crankend compression chamber.
  • A second attempt to start up the compressor again resulted in a emergency stop. Again, the shutdown was a result of two protection limit violations.
  • The next step was to open the compressor.

Findings

After consultation with the customer it turned out, that a lube oil accumulation in the compression chamber on the crank side was the root cause of both shutdowns. The reason for this accumulation was a too long lead time of the lubricating oil pump before compressor start up.

Lessons learnt

  • Liquids in the compression chamber are detectable with PROGNOST
  • This real life case underlines the necessity to properly monitor vibrations at the dead center points (TDC and BDC).
  • It´s an undeniable fact that larger amounts of uncompressed liquids cause massive and costly damages.

Leave a Reply

Your email address will not be published. Required fields are marked *

0 Comments
scroll to top