INDUSTRIAL ENERGY FACILITY (TURBINE HEALTH DIAGNOSTICS)
Customer: Large industrial energy recovery facility
Asset: Turbine train (GTA 1) 12 MW
Industry: Waste-to-energy / process industry
Context: Monthly vibration checks and continuous displacement monitoring had not identified any anomalies.
Problem Statement
- During a major shutdown on an adjacent turbine (GTA 2), the customer discovered significant mechanical damage even though traditional vibration techniques had reported normal behaviour.
- With GTA 1 approaching its own shutdown and conventional methods still showing no alerts, the customer required a contradictory, more sensitive diagnostic to assess true mechanical condition.
- Impact: High risk of undetected mechanical deterioration leading to costly downtime and repairs.
POC Objective
- Provide an independent assessment using torsional vibration analysis.
- Determine the actual mechanical state of the turbine shaftline.
- Identify early-stage issues not detectable with standard vibration or displacement sensors.
Measurement Setup
- Technology: Torsional vibration analysis from speed-sensor signal
- Parameters analyzed: Angular speed variation, angular displacement, shock index
- Comparative analysis: Before and after mechanical intervention (retightening of bearing pads)
Key Findings
Torsional vibration identified abnormalities that traditional vibration measurements missed:
Before Maintenance
- Irregular angular speed (~33 RPM mean)
- Large angular displacement variations (~0.05°)
- High shock index, indicating dynamic instability
- Bearing looseness inferred from torsional signatures
After Corrective Action (Retightening of Bearing Pads)
- Angular speed stabilised around 4.5 RPM
- Angular displacement reduced to 0.035°
- Shock index became stable and low
Mechanical Assessment
- Inlet and exhaust bearings showed reduced mechanical support
- Radial instability in turbine wheel guidance
- Structural stiffness asymmetry due to civil anchoring
Action Taken by Customer
- Inspection during shutdown
- Retightening of bearing pads
- Review of structural anchoring and bearing clearances
Benefits & Outcome
- Early detection of bearing looseness and structural issues
- Prevention of potential turbine damage
- Provided clarity where conventional vibration techniques had failed
- Enabled proactive corrective action before shutdown
Potential Savings to Customer
- Avoided high-cost turbine overhaul or failure
- Prevented unplanned outage
- Reduced maintenance uncertainty
- Improved operational reliability through early detection