Problems with unpowered ammonia recovery expanders
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When our company was using a non-powered ammonia recovery unit, we noticed abnormal noise from the expander, with its rotation speed being around 20,000 r/min, whereas the normal speed should be around 60,000 r/min. Could experts please tell us what could be causing this?
It is necessary to remove and inspect it to determine whether the expander rotor is damaged.
The speed of the expander in our company’s unpowered ammonia recovery unit is around 90,000–120,000 revolutions per minute.
The speed of the expander in our company’s unpowered ammonia recovery unit is around 80,000–90,000 revolutions per minute. Previously, there were two instances where the expander made loud noises and its speed did not meet the required levels ； Inspection revealed damage to the expander (in some cases, the expansion wheel was damaged; in others, the positioning pins between the rotor and the expansion wheel were damaged, or the gas bearings were damaged, etc.). Main reason: The system pipelines are dirty ； The pressure regulating valve on the inlet gas bearing pipeline is damaged, preventing the gas pressure in the bearing from remaining stable ； The capacity of the membrane-type exhaust gas dryer is relatively low.
The speed difference is too large; it’s better to stop and check it!
Check the expander; there must be a problem. Make sure that the gas entering the expander does not contain too much moisture, as this can damage the expander due to fluid shock. In the future, pay attention to drying the exhaust gases, and also avoid using too high a rotation speed. It’s sufficient to ensure a balance between the ammonia recovery capacity without power and the ammonia recovery achieved through membrane separation