Home Search Emissions Pollutants About the Database

Valero (26003), Norco

Releases of Nitrous Oxide

LDEQ Accident Number
Accident Date
Point Source(s) Notes Amount of Release

Flare 1 EIQ 15-77; Flare 2 EIQ 12-81
Cause: Loss of power, control valves failed. Power interruption caused by 3rd party electricity provider. Battery back up system damaged when it received a power surge during restart of refinery after Hurricane Katrina.

Followup: Yes

Notes: reduced feed rates to our West Plant
24.0 pounds

Flare 1 EIQ 15-77; Flare 2 EIQ 12-81
Cause: During startup of unit, one wet gas compressor failed to start as expected due to unanticipated electrical problems. Process gases normally routed through this compressor were diverted to the flare.

Followup: No Information Provided

Notes: Compressor repaired as quickly as possible.Air filter clogged with debris. Inspection of air filter has been added to preventative maintenance schedule.
351.0 pounds
78487 ; 78475 ; 78488

Flare 1 EIQ 15-77
Cause: MSCCU wet gas compressors tripped due to problems with common lube oil system.

Followup: Yes

Notes: Reduced feed rate to MSCCU. Issue involves wet gas compressor as seen before. Follow up report sent on June 6, 2005 with remedies: redesign of the nitrogen regulator and replacement of the pressure controller on the lube oil system
108.0 pounds

Flare 1 EIQ 15-77
Cause: Compressor tripped due to low lube oil differntial pressure on the 2nd stage of the compressor. Root cause investigation not complete at the time


Notes: Total pounds emitted from both flares. Remedial actions of reducing feed rate and reducing the reaction temperature so that the offgas to the flare can be reduced. No procedures or preventive measures identified at that time.
253.4 pounds

No Information Given
Cause: Loss of steam caused by a lack of water from the boiler water feed pumps. Pump suctions were plugged. Yarway valves were worn and were by passing more water to the pump suction drum than expected. Both resulting in low water flow to the boilers.

Followup: Yes

Notes: NO original incident report in this file. Instituted additional procedures to require personnel to measure pump suction pressure during routine rounds to determine whether or not the pump suction is plugged. Added procedures to monitor the discharge pressure of the Yarway valves to ensure proper operation. INstalled an alarm ont he control valve to indicate for low water discharge. conditions. There was

EQT 0360 Flare No. 4
Cause: The Hydrotreater/Hydrocracker (HTHC) recycle compressor malfunctioned, which initiated a shutdown of the HTHC and led to a reportable quantity of sulfur dioxide. The cause of the malfunction is under investigation while the unit is being repaired. Permitted emissions for H2S, VOC and SO2 was exceeded for 1 hour. The unit depressured in approximately 15 minutes, however, due to the excess production of hydrogen following the HTHC shutdown, Valero continued to flare hydrogen. Valero submitted a Notification of Case by Case insignificant activity on July 11, 2014 to cover emissions from Hydrogen flaring; therefore, hydrogen flaring was not considered within the duration of this event. Valero exceeded hourly permitted emissions for hydrogen sulfide, volatile organic compounds and sulfur dioxide at Flare 4 for one hour.

Followup: Yes

Notes: Shutdown of HTHC unit. Air monitoring was conducted downwind of the refinery. No procedures or preventive measures given at the time of the report. Follow up report lists the following measures identified to prevent recurrence: 1) Review this incident with affected personnel and attach sign off sheet 2) Investigate installing knock out put upstream on dry gas seal (DGS) panel inlet filters with continuous blowdown 3) Investigate the need for level indication and drains on the make-up gas (MUG) discharge pulsation dampers 4) Use recycle gas to supply panel when sufficient differential pressure is available and modify procedures accordingly 5) Evaluate the functionality of the TriLogger system and determine if upgrades are needed 6) Review the lubrication program for HTHC compressors 7) Run drain lines from the dry gas seal panel filters to a safe location for liquid removal
8.1 pounds