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|State Police #||11-01364|
|Pollutant||Duration||Point Source||Greenhouse Gas||Criteria Pollutant||Ozone forming chemical||Amount of Release|
|Carbon Monoxide||45h||GO-1 Elevated Flare (EPN1-90)||NO||YES||NO||40,228.0 pounds|
|Nitrogen Oxide||45h||GO-1 Elevated Flare (EPN1-90)||NO||YES||YES||7,393.3 pounds|
|Particulate Matter||45h||GO-1 Elevated Flare (EPN1-90)||NO||YES||NO||1,391.7 pounds|
|Sulfur Dioxide||45h||GO-1 Elevated Flare (EPN1-90)||NO||YES||NO||1,152.1 pounds|
|Volatile Organic Compounds (VOCs)||45h||GO-1 Elevated Flare (EPN1-90)||NO||NO||YES||21,784.6 pounds|
|1,3-Butadiene||45h||GO-1 Elevated Flare (EPN1-90)||NO||NO||YES||2,287.5 pounds|
|Benzene||45h||GO-1 Elevated Flare (EPN1-90)||NO||NO||YES||782.1 pounds|
|Hexane||45h||GO-1 Elevated Flare (EPN1-90)||NO||NO||NO||370.3 pounds|
|Toluene||45h||GO-1 Elevated Flare (EPN1-90)||NO||NO||NO||264.8 pounds|
Accident Classified As: Reportable Quantity
Faulty Positioner ina control valve caused high levels in a suction drum. This caused the PGC to shutdown. The control valve was tested and returned to service. On March 11, 2011, the Process Gas Compressor (PGC) shutdown due to a high level indication in the fourth stage suction drum. The PGC is designed to shutdown under this condition to protect the compressor. Flaring occurred at the GO-1 Elevated Flare (EPN1-90) as a result of the PGC shutdown. Additional flaring as a result of this upset also occurred at Motiva's West Operation Ground Flare and will be addressed in a separate letter.
This incident was not preventable by Shell Chemical. The failure of the positioner in the control valve was unexpected.
The PGC was checked and secured by operations. Feed reductions to the unit were made to minimize flaring while repairs to the PGC were made. After investigating the system, a faulty positioner in a control valve was identified as the cause of the high level in the suction drum that led to the PGC shutdown. Maintenance personnel replaced the positioner and the control valve was tested and placed back in service. The PGC was safely returned to normal operating conditions. Once the GO-1 Process Unit was returned to normal operating conditions the flaring was stopped. An alarm point will be installed to give operations an indication that the control valve is not functioning properly and allow for maintenance inspection prior to failure.