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Shell Chemical East (26336), Norco

Releases of NOx

LDEQ Accident Number
Accident Date
Point Source(s) Notes Amount of Release
145085

2012-12-02
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.
32,445.7 pounds
150876

2013-09-08
OL5 Elevated Flare (EPN 6-84) and Ground Flare (EPN 7-84)
Cause: On the night of September 8, 2013, Shell Chemical's OL-5 Unit experienced plugging of their online recycle filter located on the bottom of the pyrolysis fractionator (pyrofrac). Once plugged, the level at the bottom of the pyrofrac increased resulting in the level of the quench drum to decrease. This resulted in diversion of feed from several furnaces at OL-5. While stabilizing the OL-5 process unit, operations personnel experienced an upset in the process streams that resulted in flaring at the OL-5 Elevated Flare and OL-5 ground flare.

Followup: Yes

Notes: To minimize impacts, OL-5 operations made various process adjustments, while taking the furnaces off line. These adjustments stabilized the unit and reduced, eventually eliminating, the flaring. These adjustments also prevented the unit from shutting down. To prevent future occurrences, additional filters will be installed to create a robust filtering system. Report states that all released materials were dispersed naturally in the atmosphere from the OL5 Ground and OL5 Elevated flare stacks. Initial report stated that no reportable quantities were exceeded. Following the investigation and calculations, Shell Chemical confirmed they exceeded the reportable quantity for highly reactive volatile organic compounds.
1,487.6 pounds
149323

2013-06-20
EPN 1-90 GO-1 Elevated Flare FE-602
GO-1 Elevated Flare
Cause: On June 20, an upset in the Shell Chemical's GO-1 unit caused by the AC Converter high temperatures due to unforeseen low hydrogen purity from the Pressure Swing Absorber which was started up and placed in service following the GO-1 South turnaround. The unforeseen low hydrogen purity prompted operations to divert feed to the elevated flare to prevent an off specification incident with ethylene production. This resulted in flaring at the GO-1 Elevated Flare (EPN 1-90).

Followup: No

Notes: GO-1 operations took the necessary steps to minimize flaring, restart the PSA and safely return the unit to normal operating conditions. The PSA was isolated from the header and remained isolated until lab samples indicated on specification hydrogen. To prevent recurrence, operations will incorporate additional guidance and operational measures into the PSA start up procedures to proactively identify unforeseen low hydrogen purity. The procedure will be updated with steps to ensure on specification hydrogen prior to introducing into the header. Shell claims no reportable quantities were exceeded, but CO and NOx emissions exceed lb/hr permit limits.
221.3 pounds
148703

2013-05-10
1-90 (GO-1 Elevated Flare, FE-602)
5-84 (West Ops Elevated Flare, FE-601)
8-84 RCCU Elevated Flare (FE-201)
Cause: On May 10, Motiva's Residual Catalytic Cracking Unit (RCCU) discovered a catalyst leak in the unit's second cyclone dip leg. Operations responded immediately and worked to isolate this section of the unit. However, due to the location of the leak it was determined the line could not be isolated without diverting the RCCU process unit to hot circulation. The diverting process required flaring at the GO-1 Elevated flare (EPN 1-90) and West Ops Ground Flare (EPN 9-84). Additional flaring occurred at the Motiva RCCU Elevated Flare (EPN 8-84). Emissions from that flare should be addressed in a separate letter from Motiva. The reintroduction of Motiva's RCCU untreated dry gas resulted in the shell GO-1 unit flaring to the West Ops Elevated Flare.

Followup: Yes

Notes: Once system was secured, Motiva's maintenance personnel began repairs at the catalyst leak point. By May 12, the repairs on the system were completed and the system was returned to service. The diversion and reintroduction of RCCU Untreated Dry Gas caused the Shell GO-1 unit to flare to the GO-1 Elevated Flare (EPN 1-90) until unit specifications were met. This flaring exceeded reportable quantities.
1,651.7 pounds
148703

2013-05-10
1-90 (GO-1 Elevated Flare, FE-602)
5-84 (West Ops Elevated Flare, FE-601)
8-84 RCCU Elevated Flare (FE-201)
Cause: On May 10, Motiva's Residual Catalytic Cracking Unit (RCCU) discovered a catalyst leak in the unit's second cyclone dip leg. Operations responded immediately and worked to isolate this section of the unit. However, due to the location of the leak it was determined the line could not be isolated without diverting the RCCU process unit to hot circulation. The diverting process required flaring at the GO-1 Elevated flare (EPN 1-90) and West Ops Ground Flare (EPN 9-84). Additional flaring occurred at the Motiva RCCU Elevated Flare (EPN 8-84). Emissions from that flare should be addressed in a separate letter from Motiva. The reintroduction of Motiva's RCCU untreated dry gas resulted in the shell GO-1 unit flaring to the West Ops Elevated Flare.

Followup: Yes

Notes: Once system was secured, Motiva's maintenance personnel began repairs at the catalyst leak point. By May 12, the repairs on the system were completed and the system was returned to service. The diversion and reintroduction of RCCU Untreated Dry Gas caused the Shell GO-1 unit to flare to the GO-1 Elevated Flare (EPN 1-90) until unit specifications were met. This flaring exceeded reportable quantities.
5.8 pounds
148703

2013-05-10
1-90 (GO-1 Elevated Flare, FE-602)
5-84 (West Ops Elevated Flare, FE-601)
8-84 RCCU Elevated Flare (FE-201)
Cause: On May 10, Motiva's Residual Catalytic Cracking Unit (RCCU) discovered a catalyst leak in the unit's second cyclone dip leg. Operations responded immediately and worked to isolate this section of the unit. However, due to the location of the leak it was determined the line could not be isolated without diverting the RCCU process unit to hot circulation. The diverting process required flaring at the GO-1 Elevated flare (EPN 1-90) and West Ops Ground Flare (EPN 9-84). Additional flaring occurred at the Motiva RCCU Elevated Flare (EPN 8-84). Emissions from that flare should be addressed in a separate letter from Motiva. The reintroduction of Motiva's RCCU untreated dry gas resulted in the shell GO-1 unit flaring to the West Ops Elevated Flare.

Followup: Yes

Notes: Once system was secured, Motiva's maintenance personnel began repairs at the catalyst leak point. By May 12, the repairs on the system were completed and the system was returned to service. The diversion and reintroduction of RCCU Untreated Dry Gas caused the Shell GO-1 unit to flare to the GO-1 Elevated Flare (EPN 1-90) until unit specifications were met. This flaring exceeded reportable quantities.
333.8 pounds
148252

2013-04-20
GO-1 Elevated Flare, FE-602
Cause: On April 20, 2013, GO-1 operations restarted compressor K5741 after planned maintenance was executed. During the restart event, GO-1 flared dry gas at the GO-1 Elevated Flare (EPN 1-90) until the dry gas met specification to be used feed in the unit. The GO-1 flaring resulted in no reportable quantities exceeded but a permit limit exceedence of 46.32 lbs of Hexane.

Followup: No

Notes: The cause was a mechanical failure of the compressor check valve that required a dry gas compressor shutdown to repair. Once repairs were completed, dry gas must be flared until it meets specification to be used in the unit. An investigation determined the cause was the mechanical failure of the compressor check valve. This required a dry gas compressor shutdown to repair. Shell Chemical procedures require that the dry gas must be flared until it meets specification to be used in the unit.
430.7 pounds
148176

2013-04-19
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.
386.3 pounds
155267

2014-04-15
OL5 Unit RV
Cause: On 4/15/14, Shell Chemical's OL5 Unit flared process gas at the OL5 Ground Flare due to a relief valve (RV) on the ethylene product heater unexpectedly lifting. The pressure transmitters and gauges throughout the ethylene product system did not indicate any abnormal unit operation. It was determined that the relief valve malfunctioned by lifting prematurely.

Followup: Yes

Notes: To minimize additional unit upsets and impacts, operations personnel verified the readings from the pressure transmitters and gauges throughout the ethylene product system. Operations personnel safely removed the malfunctioning RV from services and subsequently replaced it. The malfunctioning RV was replaced on 4/22/14. Note that some reporting inconsistencies should lead to questions about the actual amounts released. For example, the refinery report suggests that total VOCs and HRVOCs are the same in the reporting documents. Further, some calculation errors seem apparent, as seen in the last row of table V.5; researcher asserts that the value in the last cell should be 0.23 rather than 100.23.
261.0 pounds
153803

2014-02-06
BD5 Unit
Cause: On 2/6/14, a vent heater from Shell Chemical's Butadiene 5 (BD5) Unit to the OL5 process gas compressor (PGC) unexpectedly froze during inclement weather, resulting in flaring at the OL5 ground flare. Once the header thawed, the unit was safely returned to normal operating conditions on 2/7/14, and the flaring stopped.

Followup: Yes

Notes: To minimize additional unit upset conditions and impacts, the vent stream from BD5 was routed to the flare until the header thawed. Once thawed, the vent stream was returned to its normal routing and BD5 was safely returned to normal operating conditions. To prevent the reoccurrence of this incident, the use of heat tracing and the development of a procedure to mitigate the frozen header are being evaluated. Both the reportable quantity and permit limit for 1,3 butadiene were exceeded.
36.0 pounds