At an onshore gas terminal (OGT) On 14-04-2015, at around 22:40 Hrs, heavy rain with the wind was witnessed and later at around 23:06 Lean amine charge pump, 11-P-103A which was running normal suddenly tripped on Axial Displacement High High (11-VAHH 3111A, 1 out of 2 logic).
At the substation, the Rotor lock alarm appeared and the start delay timer got activated for 3000 sec. Immediately at 23:16 hrs, Pump-B (11-P-103B) was started, but it was tripped on overload, and the start delay timer got activated for 3000 sec at the substation.
Later Pump-B start delay timer was reset and it was again started @ 23:55 hrs, and the plant was stabilized. The event caused a production loss of 1 hour.
A team is formed to identify and perform root cause analysis for the following incidents:
Equipment information | Failure information |
Unit: Gas Sweetening Unit (GSU) Train-1 | Date of Failure: 14/Apr/2015 |
Service: Lean Amine Service | Time of Failure: 23:06 |
Equip. Tag No.: 11-P-103 A LA Charge Pump | Failure Category: Operation upset |
Equip. Tag No.: 11-P-103 A LA Charge Pump | Failure Impacts: Production Loss |
Equip. Criticality: Critical |
Following are the observations after performing relevant mechanical, electrical, and instrumentation checks on Pump-A:
Following are the observations on Pump-B:
Following are the recommendations to avoid Amine Pumps tripping due to
Equipment | Department | Recommendations | Remarks |
11-P-103 A/B | Operations | Revision/modification of existing SOP for Amine Pumps operation | To avoid overload tripping of the motor during start-up |
11-P-103 A/B | Instrumentation | Install rain protection casing tube on the Vibration Probes cable loops and seal it with Silicone Sealant | To prevent water ingress into the system during rains and leading to malfunction of probes |
11-P-103 A/B | Instrumentation | SMP for Periodic cleaning of the Vibration Probes (as Blackish foreign paste-type material observed on the tip of Vibration probe), Periodic checking of Vibration Probe linearity function, Periodic checking of Digital Output Relay function and replacement if required. | i) To avoid the accumulation of foreign & dirt material into the probes and leading to malfunction of probes ii) Preventive and proactive measure |
11-P-103 A/B | Instrumentation | 3 sec Time delay to trip may be considered in consultation with OEM with necessary MOC | To avoid spurious tripping |
11-P-103 A/B | Electrical | Thermal lockout settings to be reviewed and Relay vendor may be communicated for resolution | To ensure early availability of the pump motor for startup |
11-P-103 A/B | Electrical | Activation of Start delay timer: The maximum number of Hot / Cold Successive starts data of Motor to be obtained from OEM (BHEL) and accordingly parameterization to be done in consultation with Relay Vendor | To ensure early availability of the pump motor for startup |
11-P-103 B | Electrical | Locked Rotor Alarm: Review of relay settings | The points to be considered during Relay co-ordination study for optimum settings as per the current operation of motors |
11-P-103 B | Mechanical | Check pump rotor and bearings healthiness | To avoid Locked Rotor Alarm |
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