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Valero (1238), Meraux

Causal Factor: Corrosion

LDEQ Accident Number
Accident Date
Point Source(s) Notes Amount of Release
97825

2007-07-12
Thermal Reactor
Cause: MOUSA shut down the #2 SRU in order to inspect a visible leak in the Thermal Reactor. MOUSA found localized corrosion damage to the shell resulting from acid gas infiltrating a small defect in the refractory.

Followup: No Information Provided

Notes: This incident was not preventable because the leak in the Thermal Reactor was not a predictable event. Remedial Measures - MOUSA shut down the unit, conducted a thorough inspection, and patched the leak in accordance with API 510. MOUSA will repair the internal refractory during the next scheduled turnaround. MOUSA conducts routine on-stream ultrasonic inspections on this unit to monitor equipment fitness
Sulfur Dioxide: 113.0 pounds
108122

2008-08-16
FLARE - Boiler Feed Water System / #2 SRU Startup / Hydrocracker
Cause: corrosion damage in B-V-454 - the control systems did not allow B-V-453 and B-V-454 to run reliably in parallel, as the level controllers attempt to work independently operators were unaware that the north and south BFW systems were operating on a common BFW line because a seldom used valve was open. Operating procedures did not address the potential for imbalance in the system when B-P-006B was shut down. in order to overcome the aforementioned design flaw, operators run the level control bypass on B-V-454 on manual. MOUSA found that existing procedures did not address all potential failure events in this operational mode.

Followup: Yes

Notes: This was an incident that involved three separate incidents. It is listed as preventable because the Boiler Feed Water trip on 8/16/2008 was found to be the result of faulty design, equipment malfunction, and operator and procedural error. Emissions from the startup of the #2 SRU were part of the normal startup procedure. The hydrocracker trip on 08/20/2008 was found to be the result of operator and procedural error. REMEDIAL ACTIONS -MOUSA repaired the trays in deaerator B-V-454. They modified prores regarding boiler feed water pump operations and is investigating engineering changes to improve controls on the deaerators. Also, they are developing procedural updated regarding the startup of the Hydrocracker. They completed repairs on MUG Comp
Sulfur Dioxide: 13,897.0 pounds

107973

2008-08-12
Leaking underground oily wastewater sewer line
Cause: leaking underground oily wastewater sewer line that was corroded

Followup: No Information Provided

Notes: This was a report from Murphy to LDEQ. The incident was not preventable because the source was a corroded underground sewer line. Remedial Measures - the leaking sewer line was taken out of service and replaced with a new steel line on August 25th, 2008. Soil with signs of visual contamination was excavated and disposed off-site at Woodside Landfill, LDEQ Facility # D-063-1941. The excavated area was backfilled with approx. 75 cubic yards of clean fill. The sewer in question serves the refinery'ab building, which is scheduled for demolition within 12 months, when the new lab building is completed. NOTE: Murphy states that since the leak occurred underground that it is difficult to determine the amount of the release and the time it began. N

131892

2011-06-18
Storage tank leak
Cause: Storage tank leaking low benzene gasoline from the floor of the tank.

Followup:

Notes: Area diked to contain the spill, vacuum truck used to remove the spilled gasoline from the ground. Low benzene gasoline transfered to another tank. Impacted soil removed and samples taken for analysis.
Gasoline: 210.0 
142072

2012-08-14
#2 SRU Incineration and Boilers B-5, B-6, B-7, and TB-01
Cause: Excess emissions of sulfur dioxide at the #2 Sulfure Recovery Unity Incinerator Stack and Boilers due to the shutdown and subsequent startup of the #2 SRU and #2 Tall Gas Treater. They were shut down due to high pressure in the #2 SRU Furnace caused by plugging in the Sulfur Condenser Seal Legs. Valero has determined the root causes to be the operation of the #2 SRU with minimal acid gas feed to the unit and a steam leak into the process from a steam jacketed pipe between the Sulfur Condensor and the #4 Seal Leg. Past experience has shown that steam leaks into this system can form a mixture with sulfur and other contaminants present that can cause plugging. The reduced sulfur rate meant that there was less flow of sulfur to clear out any plugging that was forming. A corroded pipe cause the steam leak.

Followup: Yes

Notes: After a fire in the Crude Unit, the #2 SRU and many of the units that send acid gas to the #2 SRU were shutdown. To manage a building sour water inventory, Valero started up the #2 SRU with very little acid gas feed. Normally, the feed to the #2 SRU is a combination of acid gas and sour water stripper off gas with the higher proportion being acid gas. After the fire in the Crude Unit, the feed composition changed to a much higher proportion of sour water off gas. Sour water off gas contains less sulfur and more contaminants (e.g hydrocarbons and ammonia) than acid gas. Valero replaced the section of corroded pipe that caused the steam leak prior to the start up on 8/16/12. Valero will also replace all the steam jacketed piping in the #2 SRU at the next turnaround. Valero has commissioned a new acid gas transfer line from the #3 SRU that allows greater flexibility in supplying acid gas to the SRUs which will help prevent running either SRU at low gas rates. Valero will also revise the SRU operating procedures to ensure that this transfer line is used to maintain adequate gas flow. Sulfur dioxide released exceeds the reportable quanitiy of 500 pounds.
Sulfur Dioxide: 1,040.0 pounds
141477

2012-07-22
Crude Unit Fire
North Flare, South Flare, #2 SRU Incinerator Stack, Vacuum Tower Bottoms
North Flare, South Flare, #2 SRU Incinterator Stack; Vaccuum Tower Bottoms
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.
Sulfur Dioxide: 5,916.0 pounds
Hydrogen Sulfide: 32.0 pounds
Carbon Monoxide: 296.0 pounds
Nitrogen Oxide: 326.0 pounds
Particulate Matter: 2,274.0 pounds
Total Organic Carbon: 148.0 pounds