High vibration levels at the rear end of the syngas turbine
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The syngas compressor stopped operating a few days ago; when it was restarted yesterday, it shut down during startup due to excessive vibration in the turbine’s rear shaft. After working overtime throughout last night to carry out repairs, it was tried to restart early this morning (in a single-turbine test without the compressor), but it stopped again owing to excessive vibration in the turbine’s rear shaft. Please, friends, help analyze the reasons.
What are you working overtime to fix? Have you checked the tiles? Did the oil temperature change significantly during the single-unit test run?
The poster should check whether the alignment or the tightness of the bolts meets the requirements. You can also check the temperature of the steam.
The turbine and compressor are not connected; when testing the turbine, there is no need to consider alignment issues. The steam pressure is 3.3, and the temperature is 376 degrees
To know how the vibration changes with rotational speed, and what the critical value is. What maintenance work was done. Are there vibration spectra?
For diagnosis, please describe the situation: 1. The vibration is high; why is maintenance required? What maintenance is being carried out? 2. What are the contents of this maintenance? Problems found? 3. Why was it parked a few days ago? How was the parking process? Are there any abnormalities? 4. Has there been any change in the previous vibration value? 5. During the start-up process, at how many revolutions does the machine shut down? 6. Key point: Are there any relevant status monitoring records?
It is best to upload the start and stop records, diagrams, as well as the reasons for parking and the location of the maintenance. The issue of vibration is very complex; different people have different opinions on it
I wonder if the crankshaft rotation device was activated in time during that parking incident when you were unable to start the vehicle, and also whether the vehicle was properly warmed up before starting this time. Were the exhaust temperature and exhaust pressure normal during the warming-up process?
The high vibration levels during the individual testing of the turbine may be due to 1. whether the measuring instruments are properly calibrated. 2. Has the concentricity of the rotor been properly adjusted? 3. Are the bearing shells installed properly?
1. The maintenance was carried out because the boiler caused an emergency shutdown; before the shutdown, the temperature of one bearing at the low-pressure end of the compressor was high, approaching the alarm threshold, hence maintenance was necessary. 2. The maintenance is mainly focused on the temperature of the compressor bearing shells. 3. A few days ago, an emergency stop was triggered while parking; the turbine was functioning normally at that time. 4. The vibration level in front of the turbine is below the alarm threshold, but it is higher than during normal operation. 5. Stop the machine after about 100 revolutions of rotation. 6. There is vibration recording
The last edit to this post was made by Man Tian Fei Xue on 2011-9-21 at 16:59. From the perspective of the device itself (excluding operational factors), the main reason for high vibration levels is an issue with the radial bearings (wear of the bearing pads)； Once again, it’s the lubricant issue (solid impurities). I wonder what the maintenance workers at your factory are fixing, and have they identified the cause after taking it apart? If you claim to have fixed it without identifying the cause, then there is a technical problem with your equipment managers and maintenance workers! Just to add: was there no drainage after shutdown, and no nitrogen protection?