Abstract: A shutdown resulted from the failure caused by the bearing wear of the liquid propylene discharge pump in a polypropylene device occurred after startup. Through analysis on the site situation, pump’s internal structure and physical property of propylene under operating conditions, it is found that when the flow control of external flushing propylene is not stable, the axial thrust of the pump is increased, so that the friction between the internal components of the pump is intensified. Then heat is accumulated gradually, leading to dry-running of the pump and fragmentation of the pump bearing due to wear and tear. A small range flowmeter and needle valve are added on the flushing line to accurately control the flow rate of the external flushing propylene, which obtains good results. The pump has been running smoothly after the revamp. In addition, through analyzing the pump process conditions, suggestions for pump selection are proposed.

Key words: liquid propylene discharge pump, wearing of bearing, external rinse, fault analysis, solution