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Shell Chemical East (26336), Norco

Releases of Ethylbenzene

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

OL-5 Elevated Flare (EPN 6-84)
Cause: On December 2, 2012, Shell Chemical's OL-5 Process Unit experienced an unexpected leak of the Core Exchanger, which led to flaring at the OL-5 Elevated Flare to isolate the leaking exchanger, repair, and return it to service. The release began on December 2, 2012 at 6:15 AM and ended on December 6, 2012 at 11:55 PM. Repairs were made to the core exchanger and the unit was safely returned to normal operations conditions.

Followup: Yes

Notes: The unit was secured and adjustments made to minimize flaring. Preparations were begun to complete repairs to the core exchanger. The flaring was stopped once the repairs were completed and the OL-5 process unit was safely restored to normal conditions. To prevent recurrence, maintenance practices were reviewed and improvements were made. Entire PDF report was not able to be uploaded. Contact LABB for the full report.
508.2 pounds

OL-5 Elevated Flare FE-101 (EPN 6-84); OL-5 Ground Flare FG-101 (EPN 7-84)
Cause: On March 12, 2012 Shell Chemical's OL-5 Unit Operators got an indication that the Process Gas Compressor (PGC) first stage control valve had opened to the flare system due to high suction pressure. The PGC turbine had slowed down causing the kickback valves to open. Slowdown of the turbine was caused by a high level in the surface condenser. The materials were released from OL-5 Elevated Flare FE-101 (EPN 6-84) and OL-5 Ground Flare FG-101 (EPN 7-84).

Followup: No

Notes: OL-5 Operations lowered the surface condenser level and the kickback flows to lower the first stage suction pressure. These actions stopped the flaring. All materials routed to flare were combusted with an approximate destruction efficiency of 99.5% released from the OL-5 Elevated Flare and Ol-5 Ground Flare to the atmosphere and dispersed naturally. Maintenance was called in to troubleshoot the surface condenser level indication. Instrument mechanics checked level controller and found dirt on the flapper nozzle. The nozzle was cleaned and proper operation of the control valve was checked. Instrument mechanics also found the door to the instrument center in the open position, which possibly allowed dirt into the enclosure. Operational rounds have been updated to include the task to check enclosure doors. Propylene is listed in the LDEQ's Verbal report as having been released as well, but there is no mention of it later on in the follow-up report from Shell. The measurements were obtained by adding the same pollutants from both flares together. Initial report states material did go offsite. Air was monitored around the perimeter of the facility. No reportable quantities were exceeded, but permit levels were exceeded for ethylbenzene, toluene, and xylene.
1.2 pounds

Relief valve in the OL-5 Process Unit
Cause: While making an inspection round on January 12, 2012, OL-5 operators found that a relief valve in the OL-5 Process Unit was leaking out of the vent connection. Process data does not indicate that the relief valve reached a high enough pressure to open. This relief valve has a bellows and the bellows top flange ring was found to be cracked in the rolled edge. The crack was approximately 1.5" long, and is believed to be a manufacturing defect. The valve has been returned to the manufacturer for inspection.

Followup: No

Notes: The operators immediately stopped the pump that supplies the pressure to this relief valve and the relief valve was blocked in per mitigation plan. The crack was approximately 1.5" long, and is believed to be a manufacturing defect. The valve has been returned to the manufacturer for inspection. The discharged was released mainly to a stormwater concrete containment area. There is some evaporation into the atmosphere. Vacuum truck cleaned up remaining material. Only benzene was above a reportable quantity during this leak.
1.7 pounds

OL-5 Elevated Flare, FE-101
Cause: On April 19, 2013 Shell Chemical's OL-5 Process Unit experienced an unexpected upset that led to flaring at the OL-5 Elevated Flare (EPN 6-84). The flaring was caused by high pressure on the process gas compressor (PGC) first stage suction drum. A pressure increase on the suction drum was due to the PGC slowing down as a result to the loss of vacuum on the compressor surface condenser. The surface condenser vacuum was lost due to a faulty level indication causing the loss of vacuum on surface condenser. The PGC upset also caused OL-5 cold-side to flare propylene off the outlet of the map converters because of a low flow shutdown of the converters.

Followup: No

Notes: OL-5 operations field verified the level int he PGC surface condenser and took corrective actions to safely return the unit to normal operating conditions and stop the flaring. OL-5 Maintenance repaired the PGC surface condenser level transmitter. Control systems adjusted the vacuum alarm setting for the PGC surface condenser to warn operators before the surface condenser vacuum is lost. Final calculations confirm that no reportable quantities were exceeded. The maximum permitted limits were exceeded for particulate matter, ethylbenzene, toluene, and xylene.
2.7 pounds

DU-5 Unit
Cause: On September 12, 2014, Motiva's DU-5 unit received a shipment of crude oil that contained an unusually large amount of water. DU-5's normal operations removes the water from the crude and sends the water to the unit desalters. The large volume of water that was removed from the crude formed an emulsion which caused the desalter level instrumentation to malfunction. After the desalters, the water is routed to the sour water drum, but due to the instrumentation malfunction on the desalter, the water sent to the sour water drum exceeded the volume that could be pumped from the drum. The water sent to the sour water drum overflowed into the Low Pressure Flare Header. Once the water overflowed to the Low Pressure Flare Header, the liquid went to the Shell Chemical LP Utilities East Flare Pot and was combusted at the Utilities East Flare.

Followup: No


Process gas compressor in OL5 Unit
Cause: On 3/6/2014, Shell Chemical's OL5 Unit flared process gas at the OL5 Elevated Flare due to low seal oil pressure on the process gas compressor (PGC). To improve the performance of the seals on the PGC, operations manipulates valves on the PGC seal oil system. While shifting from automatic operation of the pressure controller on the second stage seal of the PGC to manual operation of the pressure controller, the valve on the pressure controller closed and caused low seal oil pressure. As a result, the PGC unexpectedly shut down as a safety measure to prevent potential catastrophic failure of the equipment.

Followup: Yes

Notes: To minimize additional unit upset conditions and impacts, the OL5 Unit was safely stabilized. Operations adjusted the valve on the pressure controller and the seal oil pressure was restored. Operations was able to safely restart the PGC and return normal operating conditions. To prevent the reoccurence of this incident, it will be determined if tuning adjustments are needed on the pressure controllers associated with the PGC operation. As an additional precautionary measure, all employees that operate the PGC will review the transfer process for these local controllers. In the report, it is stated that the process gas was flared at the OL5 Elevated Flare. Later in the document both the OL5 Elevated Flare (EPN 6-84) and the OL5 Ground Flare (EPN FE-101) are implicated in the flaring of the process gas. There is some improper labeling on the EPN number in the tables, but it appears that the flaring occurred at both flares simultaneously. As such, all values released are combined in this database.
8.0 pounds

OL-5 Ground Flare (EPN 7-84) and OL-Elevated Flare (EPN 6-84)
Cause: xylene, toluene, 1-3 butadiene, benzene, carbon monoxide, ethyl benzene, nitrogen oxide, particulate matter, volatile organic compounds, and sulfur dioxide flared at the OL-5 Ground Flare (EPN 7-84) and OL-Elevated Flare (EPN 6-84). The flaring resulted from a unit shutdown to repair the C2 Splitter Exchanger that was leaking.

Followup: No

Notes: There is no information on the amounts nor an incident ending date. The anticipated end time was reported as 1/17/2014. Shell stated they would provide an update within 60 days of the initial report on 1/9/2014 as of 9/5/2014 there has yet to be any kind of follow up report from Shell regarding this matter.