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Valero (26003), Norco

LDEQ Accident Report

Accident #146196
PDF AvailablePDF
State Police #13-00300
Accident Date2013-01-21
Report Date 2013-01-25
Follow-up Date 2011-03-11
Follow-up: Yes

Pollutants Released

Pollutant Duration Point Source Greenhouse Gas Criteria Pollutant Ozone forming chemical Amount of Release
Carbon Monoxide39mFlare 1 and 2NOYESNO217.2 pounds
NOx39mFlare 1 and 2NONOYES39.9 pounds
Particulate Matter39mFlare 1 and 2NOYESNO1.4 pounds
Volatile Organic Compounds (VOCs)39mFlare 1 and 2NONOYES1.6 pounds
Sulfur Dioxide39mFlare 1 and 2NOYESNO5,558.7 pounds
Hydrogen Sulfide39mFlare 1 and 2NONONO14.8 pounds

Accident Classified As: Reportable Quantity

Cause of Problem: Equipment Failure

The wet gas compressor in the delayed coking unit had malfunctioned. The Wet Gas Compressor (WGC) malfunction resulted from a malfunctioning lube oil turbine. The nigh prior to the incident, the lube oil turbine tripped. The backup electric pump started in "auto" to control the lube oil pressure. We restarted the lube oil turbine but were unable to shutdown the backup electric pump with the switch in 'auto'. We verified that the lube oil pressure was stable and then shutdown the electric pump. The lube oil turbine then tripped on overspeed and when we switched the backup electric pump from 'off' to 'auto' it did not restart causing the WGC compressor to trip from low lube oil pressure. We determined that the electric pump did not restart because it received a single pulse start signal that was sent before the pump was put in 'auto' causing it not to register. Additionally, the original overspeed trip was due to scoring on the Fischer actuator due to its tendency to side load. The scored piston caused the actuator to stick resulting in a lack of speed control.

Discharge Preventable - Yes

This incident was reasonably preventable.

Notes/Remedial Actions

The maximum hourly permitted emissions for hydrogen sulfide and sulfur dioxide at flares 1 and 2 were exceeded. The reportable quantity for sulfur dioxide was also exceeded. Emissions were minimized by restarting the wet gas compressor. Gas from the coker was combusted in Flare 1 and Flare 2, and the resulting combustion byproducts rapidly dispersed.