Centrifugal Compressor: Vibration and Temperature Monitoring System
Condition monitoring is the process of monitoring a parameter in equipment i.e., vibration, temperature etc., in order to identify a change which might indicative of a developing fault. Centrifugal compressor that serves as critical equipment in the Plant need to be monitored continuously to avoid any catastrophic failure which can lead to overall Plant shutdown. Condition monitoring also allows maintenance to be scheduled.
Centrifugal compressor is delivered as package including the driver either electric motor or gas turbine. It can also apply gear box depending on the design requirement. All this major part shall have their own condition monitoring to protect and monitor those part/equipment.
As a sample the following is typical requirement for the vibration and temperature monitoring for centrifugal compressor package.
Axial position monitoring on thrust bearing
- Three probe per thrust bearing with trip use 2oo3 voting logic
Shaft vibration monitoring on journal bearing
- Two probes per bearing with trip use 2oo4 voting logic (i.e., any two probes out of four installed on two bearings)
Bearing temperature monitoring (thrust & journal bearing)
- Thrust bearing: double RTD each side per bearing with trip use 2oo2 voting logic
- Journal bearing: double RTD per bearing with trip use 2oo2 voting logic
Key phasor
- One key phasor on compressor bearing
Casing vibration
- Accelerometer
Regarding the driver there will be requirement for winding temperature RTD in case of electric motor in addition to vibration and temperature monitoring on the motor bearing. For gas turbine driver it will be similar requirement like vibration, temperature and key phasor requirement in compressor above. Accelerometer can be also required on gearbox casing and gas turbine driver.
All above field instrument installed is wired to compressor control panel located on local on skid or remote location control panel in control room. Vibration monitoring is usually Bentley Nevada (i.e., BN3500 series) located inside compressor control panel or separate dedicated panel for BN monitoring system. This monitoring is connected to BN Sytem-1 if requested by project requirement. Temperature monitoring system is wired to compressor PLC control panel. Compressor control panel will also have interface with Plant DCS.
The following sample is typical configuration of vibration and temperature monitoring system showing field instrument, control panel and System-1.
Fig-1 Machine Monitoring System
