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Valero (1238), Meraux

Releases of Carbon Monoxide

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

North Flare, South Flare, #2 SRU Incinterator Stack; Vaccuum Tower Bottoms
North Flare, South Flare, #2 SRU Incinerator Stack, Vacuum Tower Bottoms
Crude Unit Fire
Cause: Valero experienced a fire in the Crude Unit. Valero reported excess emissions of sulfur dioxide, hydrogen sulfide, and particulate matter from the fire, flaring at the North Flare and South Flare and excess emissions at the #2 Sulfur Recovery Unit (SRU) Incinerator Stack. Valero was in the process of starting up the Crude Unit following an electrical transformer failure which occurred in the Vacuum Unit on July 20. Incident number 141430 associated with the power failure describes details about the power failure and emissions released directly related to the event on that date. An 8 inch piping elbow in the Crude Unit failed, releasing Vacuum Tower Bottoms (VTB) onto adjacent piping and equipment. The hot product ignited, creating a fire in the pipe rack and a pool fure beneath the Crude Unit desalters and several nearby heat exchangers. The crude unit fire began at 0130 hours on July 22, 2013. The fire was "contained" at 0330 hours, and was extinguished at 0650 hours. The total time duration of the fire was 5.4 hours. The total flaring duration lasted 40.5 hours. Valero concluded that the triggering event was the failure of a piping elbow which resulted from a thinned wall due to high-temperature sulfidation corrosion. The elbow was of carbon steal construction, in a service requiring chrome alloy construction. Valero concluded that the root cause was that poor quality control practices and procedures were utilized when the elbow was installed in 1990 by the previous owner of the refinery.

Followup: Yes

Notes: Shutdown procedures were quickly initiated for all refinery units while the Valero Emergency Response Team responded to the fire. During the event and for part of the day, periodic flaring occurred as units were placed in safe condition. The fire lasted for a duration of 5 hours 24 minutes. Flaring associated with the refinery shutdown occurred for a duration of 40 hours 30 minutes. Sulfur dioxide, estimated at 2534 pounds, and hydrogen sulfide, estimated at 27 pounds, was released at the North Flare, South Flare, and the #2 SRU Incinerator Stack. Sulfur dioxide, estimated at 3382 pounds, and hydrogen sulfide, estimated at 5 pounds, was released from the uncontrolled burning of Vacuum Tower Bottoms in the fire. Before Completion of the repairs and startup of the Crude Unit, Valero conducted PMI testing of all piping circuits potentially subject to sulfidation corrosion in the Crude and Vacuum Units. During this process, some pipin and one additional carbon steel elbow were discovered and replaced. Valero will increase the inspection frequency from once every ten years to once every 2-3 years, which is more frequent than the 5-year inspection interval specified by industry standards for Class 1 piping.
296.0 pounds

North Flare & South Flare
North Flare, South Flare, #2 SRU Incinerator, #3 SRU Incinerator
Cause: The root cause of the event was found to be equipment failure at the Entergy substation adjacent to the refinery. Due to a total power interruption at the refinery, units underwent safety shutdowns, which included venting high rates of gases to the North Flare and the South Flare. There were periods of excess opacity at both flares, as there was no controlling steam available. The boilers were also affected by the power outage. As startups proceeded, the refinery experienced some noise from relief valves and some additional sulfur dioxide emissions at the North Flare. Entergy reported that the power interruption was caused by a severe electrical fault at a 13.8 kV tie breaker at the Meraux Substation. Entergy found no evidence to support a definitive root cause. There was some evidence of bird nesting in the immediate area of the fault.

Followup: Yes

Notes: The refinery shut down all units, per written procedures. Once power was restored to the refiner, the refinery assessed and methodically restarted each unit. The refinery received one citizen complaint for odor during this event.