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Shell Chemical East (26336), Norco

LDEQ Accident Report

Accident #154274
PDF AvailablePDF
State Police #14-01019
Accident Date2014-03-06
Report Date 2014-03-13
Follow-up Date 2014-05-01
Follow-up: Yes

Pollutants Released

Pollutant Duration Point Source Greenhouse Gas Criteria Pollutant Ozone forming chemical Amount of Release
Carbon Monoxide16h 45mProcess gas compressor in OL5 UnitNOYESNO18,346.0 pounds
Nitrogen Oxide16h 45mProcess gas compressor in OL5 UnitNOYESYES3,372.0 pounds
Particulate Matter16h 45mProcess gas compressor in OL5 UnitNOYESNO635.0 pounds
Volatile Organic Compounds (VOCs)16h 45mProcess gas compressor in OL5 UnitNONOYES8,771.0 pounds
Ethylbenzene16h 45mProcess gas compressor in OL5 UnitNONOYES8.0 pounds
1,3-Butadiene16h 45mProcess gas compressor in OL5 UnitNONOYES574.0 pounds
Benzene16h 45mProcess gas compressor in OL5 UnitNONOYES90.0 pounds
Toluene16h 45mProcess gas compressor in OL5 UnitNONONO62.0 pounds
Xylene16h 45mProcess gas compressor in OL5 UnitNONONO32.0 pounds

Accident Classified As: Reportable Quantity

Cause of Problem: Process Upset

On 3/6/2014, Shell Chemical's OL5 Unit flared process gas at the OL5 Elevated Flare due to low seal oil pressure on the process gas compressor (PGC). To improve the performance of the seals on the PGC, operations manipulates valves on the PGC seal oil system. While shifting from automatic operation of the pressure controller on the second stage seal of the PGC to manual operation of the pressure controller, the valve on the pressure controller closed and caused low seal oil pressure. As a result, the PGC unexpectedly shut down as a safety measure to prevent potential catastrophic failure of the equipment.

Discharge Preventable - No

The incident was not preventable by Shell Chemical LP as the issues with the tube oil system on the PGC were unexpected.

Notes/Remedial Actions

To minimize additional unit upset conditions and impacts, the OL5 Unit was safely stabilized. Operations adjusted the valve on the pressure controller and the seal oil pressure was restored. Operations was able to safely restart the PGC and return normal operating conditions. To prevent the reoccurence of this incident, it will be determined if tuning adjustments are needed on the pressure controllers associated with the PGC operation. As an additional precautionary measure, all employees that operate the PGC will review the transfer process for these local controllers. In the report, it is stated that the process gas was flared at the OL5 Elevated Flare. Later in the document both the OL5 Elevated Flare (EPN 6-84) and the OL5 Ground Flare (EPN FE-101) are implicated in the flaring of the process gas. There is some improper labeling on the EPN number in the tables, but it appears that the flaring occurred at both flares simultaneously. As such, all values released are combined in this database.