|About the Database
|LDEQ Accident Number
|Amount of Release
|No LDEQ Reported
|F-101 & F-102
tail gas conversion unit
|Cause: the sour water strippers had a larger than normal oil layer.
Notes: the controller diverted the tail gas to the incinerators to reduce personnel exposure and the SWS evaluated levels in the feed spheres to ensure no more hydrocarbon would be sent to the SWS and SRLA; the first page of the report states that the hydrogensulfide level was exceeded from 9AM to 9PM on June 17th, and the sulfur dioxide limit from the F-101 and F-102 incinerators was exceeded- even though the actual report only states the levels of sulfur dioxi
|Sulfur Dioxide: 12.0 pounds
|No LDEQ Reported
|Tail Gas Clean-Up Unit combustor
|Cause: This Tail Gas incident violates a 2005 Consent Decree with the U.S. Environmental Protection Agency. ExxonMobil Refinery has to comply with this consent decree and file special incident summary for any incident releasing a quantity greater than 500 pounds SO2.
On May 22, 2013 an operator at the Baton Rouge Refinery (BRRF) observed a leak on the Tail Gas Clean-Up Unit (TGCU) combustor. Areas with elevated skin temperature were found on the combustor with insulation on. The team determined that the combustor would have to be shutdown to safely remove the insulation and determine the necessary repairs. At approximately 4:15 am on May 23, the unit reached reduced rates and began bypassing the TGCU and exceeded 250 ppm sulfur dioxide.
All three Claus trains were bypassing the TGCU and being routed to the incinerators by about 7:30 am the next day. The insulation was removed and additional infrared scans were performed on the combustor to establish areas for repair/corrective action. Repairs included installation of a pressurized leak box and nitrogen purge box used to mitigate vessel skin temperature increases. The repairs were complete by 22:30 pm on May 24. At 0:40 AM on May 25, natural gas from Claus 400 began routing through the combustor to bring the tail gas unit up to operating temperature. All Claus tail gas was being routed through the TGCU by approximately 5:35 Am on May 25 and the 12 hour average on the incinerator SO2 CEMs dropped below 250 ppmv SO2 at 19:00 PM on May 25.
The combustor design specified a need for personal protection associated with the heat from the combustor outer surface. During the combustor installation in 1996, insulation was installed as a barrier for the vessel outer surface temperature. However, design and installation failed to follow a procedure which specified that insulation should not be utilized for refractory lined vessels. Based on review of vessel integrity failure mechanism, it is believed that the insulation restricted heat transfer across the vessel surface and created isolated areas of elevated temperature leading to metal fatigue.
The emission calculations for the Tail Gas Exceedance are as follows: The analyzer associated with the incinerator was reading maximum range, so ExxonMobil used the following calculation to estimate the quantity of sulfur dioxide released:
Tons of SO2 = Acid Gas Rate to sulfur plant * SO2 factor based on 2009 turnaround emissions.
Where the acid gas rate = mcf/event = 26.57 mcf.
SO2 factor based on data from 2009 turnaround = tons/mcf = 2.0.
Tons of SO2 = 26/57 * 2.0 tons SO2/mcf = 53.14 tons SO2.
Notes: The refinery quickly began reducing rates and maintained reduced rates until the combustor was repaired. Additional ExxonMobil personnel worked to ensure inspections and corrective actions were completed as soon as possible. Contractors and mechanical personnel worked overtime to build and install the leak box. One corrective action that was completed at time of the facility report is the insulation was reoved from the combustor to alleviate metal fatigue mechanism. BRRF determined that the following corrective action is required: develop plan to identify and evaluate other similar refractory lined equipment within the complex for potential for metal fatigue mechanism. The corrective action is scheduled for completion by 3rd quarter of 2014. ExxonMobil will submit a final report within 30 days of the completion of all corrective actions.
|Sulfur Dioxide: 106,280.0 pounds
|Cause: An oil spill occurred at the ExxonMobil Baton Rouge Refinery on February 26, 2013. Approximately 1.5 barrels of diesel was released to the soil due to improper equipment preparation. Reportable quantities were exceeded.
Notes: At the time of the spill the weather conditions were as follows: 51 degrees Fahrenheit, 16 mph winds from the West and no precipitation. Upon discovery, mitigation measures were initiated; soil remediation was completed on March 1, 2013. The line was isolated within five minutes of discovery.
|Diesel Fuel: 63.0 gallons