Journal Bearing Temperature Spikes of Centrifugal Compressor
Journal Bearing Temperature Spikes of Centrifugal Compressor
(OP)
I work in Ammonia plant and we're experiencing a problem in our Ammonia Compressor. The temperatures of both journal bearings of centrifugal ammonia compressor (which is driven by steam turbine directly) increase in spike form, without any change in bearing temperatures of steam turbine, and without any effect in radial or axial vibration values.
Could anyone suggest a reason for such a behavior?
Could anyone suggest a reason for such a behavior?





RE: Journal Bearing Temperature Spikes of Centrifugal Compressor
If journal bearing metal temperature increases significantly, this increases oil film temperature which in turn effect load carrying and damping capability of bearings. So I am wondering how come this does not reflect on vibrational readings according to your statement.
Could it be an instrumentation problem?
Has there been changes in process which increased loading on compressor and/or its speed?
Lube oil supply, any noticed change in supply temperature, oil quality (via sample analysis)?
Any changes in lube oil system parameters (oil return temperature, heat exchanger temperatures, lube oil supply pressure, etc). Turbine may be subjected to same as compressor but may accomodate better changes in oil supply conditions (e.g. different bearing design etc.).
Has there been start/restart of machine performed recently?
Small note: you mention "axial' vibrations, these are displacements monitored due to axial thrust acting on rotor.
RE: Journal Bearing Temperature Spikes of Centrifugal Compressor
We've checked also the instrumentation, each bearing temperature on separate module, so there are no chance of instrumentation malfunction.
If it is a matter of load, axial displacement and axial bearing temperature would have been affected, which does not occur.
RE: Journal Bearing Temperature Spikes of Centrifugal Compressor
RE: Journal Bearing Temperature Spikes of Centrifugal Compressor
An instrument engineer found a bad card in the Bently 3500 rack. They changed out the card and we have not had any problems since then. We considered shutting down a gas plant when we thought this was a real bearing failure.
Johnny Pellin
RE: Journal Bearing Temperature Spikes of Centrifugal Compressor
RE: Journal Bearing Temperature Spikes of Centrifugal Compressor
RE: Journal Bearing Temperature Spikes of Centrifugal Compressor