Regarding the expander speed
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What is the rotational speed of the expander when it is operating normally? Does the speed need to be reduced first before it stops? What is the lowest possible rotational speed?
Our speed is between 28,000 and 30,000, with a linkage value of 33,000. . When parking, the RPM slowly drops to 20,000, then to 10,000. At least 10,000 or more
Our rotation speed is between 15,000 and 16,000; when stopping, it should be reduced gradually to above 5,000
It’s sufficient to quickly avoid the surge zone
The resonance zone, right? Do your expanders also gradually drop below the resonance range when they stop? ~~
There is a question: for expanders with resonance zones, what do people do when shutting down and reducing speed? ~~
There are two expanders, one with a capacity of 18,000 and the other at 28,000. The operating procedures do not specify anything clear in this regard. At full load, the emergency stop button was tested; now that I think about it, it feels quite awkward
In the past, in factories, for an air separation unit of 6000, the expansion volume was 3700. The rotation speed is 33,000; it’s overreported as 41,000. At low flow rates but high rotation speeds, the return valve remains open at over 70% of its capacity (the factory manager didn’t care about this at the time, and I didn’t understand either). When the machine stops, the rotation speed drops to around 5,000. There isn’t even a check valve installed at the pressure increase outlet; once the machine stops, the two DN200 shut-off valves rust over time – it’s really troublesome when thinking about it now