What should be the supercritical speed of a synthetic compressor?
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What is an appropriate rotational speed for centrifugal compressors in large ammonia synthesis plants when they are operating beyond the critical point? What are the figures for each factory respectively?
The critical speed of different units is not necessarily exactly the same; generally, the operating instructions for steam turbines provide the critical speed.
The critical speed of the syngas compressors in Kellogg’s ammonia synthesis plants is 25 r/min; what is the critical speed for your plants?
The general critical speed is the combined speed of the critical ranges of each cylinder. The rate across the critical zone is generally 60-100 RPM/S
This post was last edited by 654262293 on 2010-9-18 08:46. All manufacturers provide this; 5200 rpm is not meaningful as a reference.
It depends on what the manufacturer provides; the critical speed varies among different manufacturers and different model types.
The critical speed of a synthetic compressor is determined by the resonance systems such as the compressor’s shaft and rotor; the speed above this critical speed has been tested by the manufacturer or provided to users based on existing engineering experience.
As the guys upstairs said, it’s provided by the manufacturer. However, during our testing we found that there was a slight deviation from the data provided by the manufacturer; abnormalities occurred before the rotation speed reached the critical range, so we expanded that critical range slightly. I don’t understand what the reason is? It should have a chance of only one in several million, yet it still happened
The last edit to this post was made by 654262293 on 2010-9-19 at 17:11. The critical speed of a centrifugal compressor, as mentioned in post 7, is determined by the manufacturer or based on experience. It is merely a range; for specific compressors and turbines, if no modifications are made after leaving the factory, the values are generally still those from the manufacturer’s tests. However, during installation, if components have been replaced or anything of the kind, there is still a slight deviation in the critical speed, but it isn’t much. Therefore, when determining the critical speed, it is sufficient to establish a range, as this also takes into account the low-pressure, medium-pressure, and high-pressure cylinders of the turbine and compressor – each of which has a different critical speed. I wonder where the OP’s syngas compressor is from? How is the steam turbine? As a supplementary point, if something goes wrong and it can be determined that it’s not due to mechanical issues, then increase the speed as quickly as possible. Staying at the critical point is tantamount to waiting for disaster; you might not even realize when the impeller breaks apart. If a problem is detected on a device before acceleration, stop, fix it, and then restart.
Compressor units generally have n critical speeds, with only different vibration amplitude values. Each unit has a critical region, and there is a certain critical range beyond which these speeds are reached. The critical speed is not an exact value (it is usually provided by the manufacturers). The unit of 25 r/min mentioned by #3 is incorrect
Reply to 1# lc100866: Different turbines have different critical speeds. The critical speed is an inherent property of the turbine, calculated by the turbine manufacturer based on the rotor design; what we usually see is the first-order critical speed.