Occasional VI(Radial Vibration) spot peak in HYC R/G Comp. turbine
Occasional VI(Radial Vibration) spot peak in HYC R/G Comp. turbine
(OP)
Re the Hydrocracker recycle gas comp. driven by HP steam turbine, recent four VI(Radial Vibration) trends of turbine shaft show occasional spot peak around 3 times per day from normal 12~ 18 mm to peak 40 mm.(We have four VI in Turbine shaft both in exhaust and governor side). However, comp. side four VI shows no sign of spot peak, it's very stable. Re this operational phenomena, anybody who experience same problem in recycle gas comp. turbine as our VI increase, please comment me any information to solve this turbine VI spot peak.
Just for reference, there is no interlock in VI, it only generates alarm at 52 mm.
Just for reference, there is no interlock in VI, it only generates alarm at 52 mm.





RE: Occasional VI(Radial Vibration) spot peak in HYC R/G Comp. turbine
RE: Occasional VI(Radial Vibration) spot peak in HYC R/G Comp. turbine
Our Hydrocracking unit recycle gas compressor use flexible coupling and electronic governor. Also,main steam has no minerals.(checked LAB data such as SiO2)
However, I need your additional explanation to understand your phrase more precisely.
q1> Does your writing "Are there any irregularities in the seal steam or gland condensor system during events?" means seal steam or gland condenser could be the causes of occasional VI(radial Vibration) peak? If it is true, would you explain why that could be ?
q2> In our manual doesn't recommend seal steam(use Low pressure steam) injection to the gland seal during normal operation. However, I found some amount of seal steam is serviced to gland seal during normal operation. So, i'm thinking of cutting seal steam just for the case of seal steam quality is not good enough. Does this action has a chance of improving VI problem ?
q3> Would you explain the meaning of "phase angle" ?
q4> Any comments would be appreciated.
RE: Occasional VI(Radial Vibration) spot peak in HYC R/G Comp. turbine
Make sure that the seal steam and gland condensor systems are adjusted as the manufacturer recomends. Make sure you cannot be drawing in cold air along the shaft.
Examine the vibration spectra to determine the frequency at which the high vibration is occuring. Examine the shart orbit during the event to look for a possible internal rub.
When you say "Flexible Coupling" I assume you mean disk pack, diaphragm, etc. If the main drive coupling is a gear coupling, it could be intermittently locking up and causing the vibration. But I think it is more likely a rotor bow or internal rub. I almost forgot about bearing instability as a possibility. An oil whirl in a radial bearing could be an intermittent problem. This would also tend to show up in the spectra or shaft orbit.