Condition based Monitoring for gas turbines
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The document discusses the importance of gas turbines in the oil and gas industry, highlighting their role in power generation and gas compression. It details potential failures and emphasizes the significance of combining vibration and performance monitoring for effective predictive maintenance. Recommended parameters for monitoring include various performance metrics and vibration measurements to optimize maintenance and improve operational efficiency.
Condition based Monitoring for gas turbines
- 2. Overview: Gas turbines Recommended vibration parameters Potential Failures Vibration parameter measurement tools Predictive Monitoring intelligent machinery management decisions performance parameters recommended sensor selection Conclusion 2
- 4. Gas turbines are effectively used within the Oil & Gas industry as a high-power driver for gas compression and power generation. 4
- 5. • Potential Failures have different distribution depending upon the application (mechanical design, operation range, environment etc.). Investigations show that around 70% of all failures can be assigned to product faults, i.e. Material faults (e.g. due to fatigue or off design) Faults in planning Manufacturing faults Assembly and repair Most of these faults may be detected before they become critical by a system that combines vibration and performance monitoring. 5
- 6. End user of the turbine to balance the investment cost, and the cost of running a predictive maintenance system against; Higher production output, Less unexpected repairs, Optimized maintenance scheduling, Optimized machine performance, Is taken. 6
- 7. GAS TURBINE PREDICTIVE MONITORING Process parameters are used for making performance and efficiency calculations. Vibration parameters are necessary when judging the condition of the rotating parts. By combining vibration and performance data, better diagnostics can be made. 7
- 8. Recommended performance parameters: Turbine isentropic efficiency Compressor isentropic efficiency Compressor isentropic head Compressor volume flow Data corrections against atmospheric pressure, ambient temperature, relative humidity speed and differential pressure of inlet filter Heat rate (the actual heat input) Corrected heat rate Isentropic head Fuel gas consumption Air flow Gas turbine inlet temperature Firing temperature 8
- 9. Recommended vibration parameters Overall vibration level (according to API standards) Rotor synchronous amplitude and phase measurements (Minimum 1X & 2X) Casing and blade passing frequencies Journal Bearings – Gap, Orbit Rolling element Bearings – Bearing frequencies and high frequency noise Vibration parameter measurement tools DC Band Pass / Smax measurements Dual Time function with limiting filters Vector measurements – Selective Magnitude and Phase FFT - Auto spectra with zoom capability Selective Envelope Spectra CPB Spectra 9
- 10. Monitoring Set-up depends on the installed monitoring equipment and the monitoring strategy relevant for the specific application. 10
- 11. Monitoring Set-up depends on the installed monitoring equipment and the monitoring strategy relevant for the specific application. 11
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- 13. The goal is to provide the right information to the operations and maintenance personnel, where the information is accurate and timely information that can be used to make intelligent machinery management decisions, i.e.: Continue or not? If it fails, what are the consequences? Can the machine be re-started? What should be inspected? Is the machine operating efficiently? Will it last until next scheduled overhaul/service? 13
- 14. Gas turbines require vibration sensors: measuring vibration severity, the direction vibration (reference sensor) and the motion of the shafts (position relative to bearings and seals) giving: • Amplitude • Phase • Frequency When monitoring shaft vibration on gas turbines displacement sensors are recommended The sensor should be selected based on its response curve, frequency range, sensitivity and noise susceptibility 14
- 15. Bearing cap or case mounted seismic sensors (e.g. accelerometers) are useful for evaluating casing vibrations The vibration phase is measured by a reference sensor; either an infrared or displacement sensor. 15
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