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|LDEQ Accident Number
|Point Source(s)||Notes||Amount of Release|
|Tank 755||Cause: No information given|
Notes: Below Reportable Quantities; no details given other than odor complaints- but the methane release from the open hatch on Tank 755 is not believed to be the source of the odors
|tank732||Cause: C-830 compressor shut down causing ICN unit to shutdown. F-761 control valve was left on control to allowing the liquid level in the ICN product stabilizer tower to continue to tank732. Excess flammable vapor was released.|
Notes: it was discovered that the F-761 control valve had not been closed, so it was closed once discovered and the release stopped; procedures will be reviewed and appropriate corrective actions will be ma
|FLARE||Cause: the controller responsible for the operation of the Refinery Gas Compression Unit (RGCU) began experiencing problems|
Notes: C-50 was started up to eliminate the flaring and was run on manual. Incident not preventable because normal preventative precautions not used due to concern over clanging noises.
|D-104 Hydrocracker||Cause: the clamp on the Hydrocracker D-104 overhead line was leaking. The pressure of the overhead gas was reduced and several attempts were made to reseal the clamp, including trying several different kinds of sealant. The leak would stop for a short durationand then return|
Notes: As of 7:30am on 5/22/2006 - the date of this letter - the leak was ongoing. In this letter, Exxon claims states that the reportable quantities for hydrogen sulfide and flammable vapor were exceeded only during the first 24 hours of the incident. This incident was not preventable because the clamp was considered to be a permanent repair (installed in Dec. 2005) until the scheduled unit downtime in 2008. Remedial Measures- a larger engineered clamp will be installed over the existing clamp. "
|East Train Hydrofiner (HHLA-E)||Cause: -Exchanger on the East Train Hydrofiner (HHLA-E) was leaking into a cooling tower. The seating surface and gasket on the floating head were upgraded during the turnaround. Operations personnel installed the exchanger correctly . However, when the exchanger was worked offsite, the contracting company installed the wrong bolts in the floating head of the exchanger. The bolts broke due to wet hydrogen sulfide cracking which caused the exchanger to leak. Note: the accident started at 10:00am on 03/17/06 but was not discovered until 1:50pm on 03/18/2006|
Notes: The cause of the accident is listed as preventable in the company's report, but there is no explanation whatsoever as to why it was preventable - that section is blank. In the report it does state that further investigation of the incident is currently being conducted. Remedial measure are listed as - the exchanger bolts replaced with appropriate material for the predetermined run length. Reportable quantities were exceeded for hydrogen sulfide and volatile organic compounds
|FLARE - Alkylation Feed Preparation Unit||Cause: The Methyl Tertiary-Butyl Ether Unit was converted to an Alkylation Feed Preparation Unit (AFP). The AFP was beginning its initial start up. As the level in one of the towers increased, steam was added to the reboiler to begin producing overhead product. During this time, the safety valves on the tower began relieving to the flare system, which resulted in the reported flare. During the conversion of the unit the overhead pressure meter was reranged in the field, but was no reranged in the control room. Due to this oversight the operator believed he was at a significantly lower pressure and did not immediately discover that the safety valves on the tower had lifted to the flare system. The calculations automtically completed by the flare system|
Notes: The cause of the accident is listed as preventable in the company's report, but there is no explanation whatsoever as to why it was preventable - that section is blank. The only remedial measure listed is that the pressure meter range was corrected in the control room. The letter to LDEQ states that reportable quantities of nitrogen oxide and butenes were exceeded.
|Cause: Safety valve lifted and did not reseat after depressure|
Notes: Measures were taken to reduce the operating pressure on unit. Safety valve was taken out of service and will be evaluated for proper set pressure.
|Leak-tower leak||Cause: Internal and external|
Notes: Tower shut down to stop leak. Tower repaired before returned to service
|FLARE-Flare #5,20||Cause: |
Notes: Attempts were made to restart compressor and without success a back up compressor was started. Feed rates were reduced to stop flaring.
|Exchanger leak||Cause: underdeposit corrosion|
Notes: Leaking exchangers were removed from service. The metallurgy of the exchangers is being evaluated for upgrading.
|safety valve release||Cause: safety valve release|
Notes: unit feedrate was reduced until the faulty indicator could be repaired.
|FLARE-Flare #5,7,17,19||Cause: OTHER-Electrical failure of Coker units|
Notes: Personnel initiated startup of idle compressor recovering most of coker gas. Alternate electrical coordination settings and power supply designs are being evaluated for this system.
|safety valve releaes|
safety valve release
|Cause: no information given|
Notes: Exxon Mobile was authorized by LDEQ to proceed with emission plan for startup. In order for normal operation of incinerators, refinery has to emit gases through flaring, total emissions will be report once after normal operations are attaine
|safety valve release||Cause: Equipment failure-valve blocked|
Notes: a pressure indicator and associated alarms will be installed on the line to prevent a similar overpressure incident from occuring.
|Pulldown line leak/FLARE-Flare 5,17,29||Cause: Leak was discovered on the pulldown line for the Product Separator Drum at the Powerformer Unit. Initial findings indicate that the leak was caused by internal corrosion of the weld in a stagnant area of the line.|
Notes: The line could not be isolated from the drum, so the decision was made to shutdown the unit in order to stop the leak. The line was completely depressured. During the process of shutting down the unit, flaring occurred from the #5, 17, and 19 flared. No reportable quantities were exceeded as a result of the flaring. Regular air monitoring was conducted during this event. The spool piece that leaked was replaced with a straight piece of pipe to eliminate the stagnant area in the line. Reportable quantities for benzene and flammable vapors was exceeded.
|Atmospheric release/FLARE-Flare 17,19,23||Cause: The C-101 Recycle Compressor on the HCLA unit shut down due to a fault in the transformer that supplies power to the compressor motor. The compressor trip automatically activated the units emergency depressurization procedures, which caused gases in the HCLA reactor system to be vented to the atmosphere via the condensable blow down drum. The transformer failed due to overheating. The air conditioner in the substation was found to have failed causing the temperature in the building to increase and the transformer to overheat. FLaring also occurred.|
Notes: The unit was depressurized automatically in accordance with the emergency procedures. Temporary ventilation conditioning was installed in the substation to cool the remaining electrical equipment. Total amount of flammable vapor released was 108,206 pounds. Total amount of VOC's released was 93,904 pounds
|safety valve release/ FLARE-Flare 17,23||Cause: process upset/under investigation|
Notes: In response to the suspected exchanger tube leak, the unit was shut down per appropriate procedures. Safety valve inlet line was cleaned and replaced.
|leak/FLARE-Flare 5,9,19,20,24||Cause: Equipment failure-Hydrocracker unit down; Pressure Swing Absorber out of service|
Notes: Safety valve released itself once the pressure stabilized. Lights end section was depressured to stop H2S leak, which caused many flares to burn. Light ends depressured. Stream was lined up to the tower to stop flarin
|no information given/leak|
no informaiton given/leak
|Cause: no information given|
Notes: Written notification from Exxon Mobile surrounding the leak that occurred at the facility stating that no reportable quantities had been exceeded.
|Bateman Lake Natural Gas header||Cause: Technician working on pressure instrument did not notify unit operating controller. Malfunction caused pressure control valve to open, which caused the pressure in the Bateman Lake Natural Gas header to exceed that of safety vavle set point.|
Notes: A total of 2030 pounds of flammable vapor was release which exceeds RQ. Pressure control valve was taken out of automatic control and placed into manual control.
|Mixed Gas Oil tankage||Cause: The incident took place at the Mixed Gas Oil tankage. The flow valves that supply methane to the tanks fully opened when the computer control system was upgrading. The methane exceeded the tanks' vapor recovery unit, therefore their atmospheric vents opened releasing the gas.|
Notes: The computer system was returned to service, and the valve was shut. The Methane flow valve will now be manually closed when computer system is shutdown. Exxon exceeded the reportable quantity threshold for flammable vapors when combined with a second release that occurred within 24 hours.The second release had the LDEQ number 127174. Combined 1,563 pounds for both incidents. Although the 2 individual incidents are BRQ, the combined sum of 1,563 pounds is RQ.
|FLARE: #4 Unit||Cause: As the #4 unit was starting up, it had a unit swing. To relieve the pressure, flaring took place.
During the same 24 hours, the Powdered Catalyst Unit (PCLA) also underwent startup operations. Difficulties with compressor GLA-2X during startup resulted in additional flaring. As a result of this flaring, 1616 pounds of sulfur dioxide was released.
Combined, these two sources release 1,716 pounds of sulfur dioxide. However, in a follow-up letter dated March 21, 2011, ExxonMobil stated that 2,063 lbs of sulfur dioxide were released.|
Notes: This release is RQ. To end the Light Ends Flaring, pressures on the 4 West Rerun and 4 West Splitter towers were reduced. To end the PCLA flaring, compressor GLA-2X was started. To prevent recurrence, procedures will be reviewed for the Light Ends area startups following unplanned downtimes. Additionally, startup procedures for the GLA-2X compressor will be reviewed.
|flange on ICN unit||Cause: A contractor detected a hydrogen smell on compressor C-830. A flange on the ICN unit leaked Hydrogen. The leak rate was 100lbs/hr.|
Notes: Unit personnel tightened the flange and the leak was isolated. No RQs were exceeded. 60.7 pounds of hydrogen, 7.9 pounds of methane, 1.4 pounds of ethane, and less than a pound of propane was released.
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