The surge voltage caused the pre-hydrogenation feed pump to reverse rotation, resulting in the destruction of the bearing shells

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Event Name: Sudden power fluctuation caused the pre-hydrogenation feed pump to reverse rotation, resulting in damaged bearing shells. Time of occurrence: 8:05 on April 19, 1998. Course of the event: At 8:05 on April 19, 1998, a sudden power fluctuation led to the shutdown of K-4002 and K-4001/2, forcing an emergency shutdown of the hydrogenation unit. Reactor unit P-3101 was shut down. At P-3101/2, the personnel on duty, due to a misunderstanding, thought it was not shut down and failed to close the pump’s outlet valve in time; this delayed response led to the burnout of the bearing shells. Cause analysis: 1. Power fluctuations that led to a power loss in P-3101/2 were the direct cause of the bearing wear. 2. The failure to detect the reversal of P-3101/2 in a timely manner was the main cause of this equipment accident. 3. The failure of the check valve at the P-3101/2 outlet is also a major cause of material backflow and pump reversal. Precautionary measures: 1. Determine whether the pump is running in reverse by checking the motor current; if the pump is rotating but the motor current is zero, it indicates reverse rotation. Once reverse rotation is detected, the pump’s outlet valve should be closed immediately, after which it should be checked to see if the pump is still rotating. 2. Inspect the P-3101/2 check valve to ensure it functions properly. Inspect the check valves at the outlets of P-3101 and P-3101/3.