Seeking help with questions regarding centrifugal compressors
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We have a centrifugal compressor here, driven by an electric motor. Through the gearbox, the compressor operates at a speed of over 10,000 revolutions per minute. The key point is that it operates at the power frequency; once the motor starts, the compressor immediately reaches this high speed. I’m very concerned about whether the thrust bearing can withstand such high forces during startup Will the wear be severe? The compressor is equipped with balance pipes, and it starts with the inlet valve opened to about 30 percent at minimum
What is the motor power? Some manufacturers even recommend starting it directly; I think the opening angle of your guide vanes is a bit too large
The motor power is 560 kw. Do you mean the inlet valve is opened wide?
The requirement is not less than 30 percent; otherwise phenomena such as surge will occur. When the machine was started this time, to what extent were the inlet valves opened, and what were the flow rate and pressure respectively?
I haven’t driven it yet; I’ll drive it next year. I’m quite worried about the thrust bearing at the moment
There’s no need to worry; if there are any issues, you can consult the manufacturer directly.
It is recommended to learn the working principles, rather than worrying needlessly. Regarding the opening degree of the intake valve at startup, as long as the startup does not cause a current overload trip and it is low enough to prevent surging, you can choose it arbitrarily. Of course, the smaller the valve opening, the more beneficial it is for starting to meet the minimum requirements. As for the thrust bearings, the axial force is balanced based on the design of each component, so there’s no need for you to worry about it; the designer is responsible if any problems arise. In my opinion, you should be a user; it’s more practical to find a way to learn how to operate it. There are many designs for compensating the axial force at the upper balance, such as balance discs, changes in the air intake direction, and variations in shaft diameter.
The designer should have considered this, so there’s no need to worry too much; if there are any issues, you can consult the manufacturer directly.
Check some random information, or if possible, contact the manufacturer to have an on-site inspection before starting operation. You can request that the newly installed units be inspected; record the thrust clearance and compare it with the designed value – as long as it’s within the acceptable range, that’s fine. Before starting up, the technician will check and adjust the coupling alignment, and it’s sufficient to follow the operating procedures carefully during startup. Pay attention to monitoring the oil temperature, oil pressure, and oil quality. Once all these preparatory steps are done, there’s no need to worry
Follow the operating procedures, and monitor closely in case of any issues
Is there no anti-surge valve? We usually import them with a starting price of around 15. It depends on the actual situation. Observe after turning it on and figure it out on your own