Ammonia Recip Compressor Pipe Vibration Problem Solved

Positive Displacement Compressor: Excessive motion by the discharge piping of a petrochemical ammonia reciprocating compressor (positive displacement compressor) startled the operators.  MSI was tasked with finding the root cause and suggesting a fix for this rotating machinery vibration issue.

• Problem Statement (Challenge)
  • What (type of machine): Petrochemical Ammonia Reciprocating Compressor (Positive Displacement Compressor)
  • Where (State/ Country): New Jersey
  • Why (problem/reason): Operators started to notice large amounts of swaying in the discharge piping and wanted the problem investigated to prevent a potential ammonia leak.
• Work Performed
  • Methods: Experimental Modal Analysis (EMA), Condition Monitoring, Operating Deflection Shape (ODS)
• Results/ Solution
  • Findings: Resonance was identified with the compressor operating speed. This was due to a discharge piping structural natural frequency.
  • Impact: The findings suggested the installation of piping supports were necessary along the length of the discharge pipe to shift the piping natural frequency away from the running speed. A Finite Element Analysis calibrated to the data collected on site to develop a solution with a greater chance of success upon implementation was recommended to the customer.

Locations for suggested pipe supports.