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Valero (26003), Norco

LDEQ Accident Report

Accident #153607
State Police #14-00480
Accident Date2014-01-29
Report Date 2014-02-04
Follow-up Date 2014-03-26
Follow-up: Yes

Pollutants Released

Pollutant Duration Point Source Greenhouse Gas Criteria Pollutant Ozone forming chemical Amount of Release
Sulfur Dioxide1h 12mFlares 1 and 2NOYESNO5,784.0 pounds
Volatile Organic Compounds (VOCs)1h 12mFlares 1 and 2NONOYES328.0 pounds
Particulate Matter1h 12mFlares 1 and 2NOYESNO1.4 pounds
NOx1h 12mFlares 1 and 2NONOYES41.0 pounds
Carbon Monoxide1h 12mFlares 1 and 2NOYESNO223.0 pounds
Hydrogen Sulfide1h 12mFlares 1 and 2NONONO31.0 pounds

Accident Classified As: Reportable Quantity

Cause of Problem: Weather

On January 29, 2014, the Valero St. Charles Refinery (Valero) experienced flaring when the pressure on the Naphtha Surge Drum and the Wet Gas Compressor (WGC) Interstage Drum increased. The pressure controller on the Naphtha Surge Drum malfunctioned due to cold temperatures, which caused the level to rise in the drum. As a result, the level in the Compressor Interstage Drum, which is downstream of the Naphtha Surge Drum, increased and caused the WGC to trip. The pressure controller on the Naphtha Surge Drum was bypassed to the flare header in order to control high levels on additional upstream and downstream vessels with the unit. Flaring stopped after the level in the Compressor Interstage Drum was decreased and the WGC was restarted. Temperatures were below 30degF on the morning of the incident. It was found that the steam tracing on the pressure controller on the naphtha surge drum was not in contact with the valve and insulation blankets were not in place. The lack of steam tracing and insulation exposed the valve to cold temperatures, which caused it to malfunction.

Discharge Preventable - No

THe discharge might have been preventable if we had reasonably anticipated the extreme cold conditions, and our corrective actions for this incident include measures to identify and correct tracing and insulation issues in each complex of the refinery in the future. However, the extreme cold conditions that caused the WGC trip were unprecedented in this area. Please note that this incident occurred during the January 2014 winter storm addressed by LDEQ's Declaration of Emergency and Administrative Order.

Notes/Remedial Actions

The event was secured by reducing the level in the compressor interstage drum and restarting the WGC. Additionally, the Flare Gas Recovery Unit remained in operation to reduce the amount of flared gas. The following corrective measures have been identified to prevent recurrence: 1. Review this incident with affected personnel. 2. Review and revise as need the freeze protection guidelines. 3-7. Create a pre-winter checklist to identify and correct tracing and insulation issues for Complexes I-V. 8. Repair the steam tracing and insulation for PCV-53-471, LV-53-472, LV-53-020, and LV-53-038. The Reportable Quantity for SO2 was exceeded.