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Valero (26003), Norco

LDEQ Accident Report

Accident #130162
PDF AvailablePDF
State Police #11-01678
Accident Date2011-03-24
Report Date 2011-03-31
Follow-up Date 2011-05-23
Follow-up: Yes

Pollutants Released

Pollutant Duration Point Source Greenhouse Gas Criteria Pollutant Ozone forming chemical Amount of Release
Sulfur Dioxide2 h 45 m3700 SRU MalfunctionNOYESNO1,573.0 pounds

Accident Classified As: Reportable Quantity

Cause of Problem: Equipment Failure

The sulfur dioxide levels at the 3700 Thermal Oxidizer (EQT 0195) were intermittently elevated from approximately 3/24/11 from 8:40 am until 11:30 am. Valero estimates that the reportable quantity for sulfur dioxide was exceeded at 9:25 am. This event was attributed to a miscommunication between night and day-shift operators, as well as process pressure controller that needed calibration (tuning).

Discharge Preventable - Yes

This upset was preventable.

Notes/Remedial Actions

Operators moved quickly to make manual control over automatic control valves that may have contributed to this event. Operational moves were conducted on a separate sulfur recover plant to help stabilize the upset. The following measures have been identified to help prevent recurrence:(1) Tune pressure controller for amine acid gas header to 3700 SRU (2) Communicate incident and reinforce the use of shift notes when communicating important details