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Valero (26003), Norco

Releases of Propylene

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

#3 Debutanizer Reflux pump
Cause: At approximately 1:15 operators noticed that the #3 Debutanizer Reflux pump seal had failed and was releasing process gases ti the atmosphere. Seal failure was caused by a failure in the pump's thrust bearing.

Followup: Yes

Notes: Deluge water was used to contain the vapors and reduce the risk of fire. The malfunctioning pump was isolated and shut down. A redundant backup pump was started to avoid unit shutdown. Reflux pump thrust bearings will be replaced from 40 degree contact bearings to 15 degree contact bearings.
2,195.0 pounds

pump connected to tank 80-1
Cause: Portable diesel-powered transfer pump caught fire. Releases include Acetaldehyde 0.0284 lbs and Acrolein 0.0034 lbs. FIRE.

Followup: No

Notes: ERT extinguished fire in 20 mins.
0.1 pounds

FLARE: Flare #1 & #2, MSSCU, SRU, 3700 TOX
Cause: Flaring caused by difficulty starting up the Millisecond Catalytic Cracking Unit (MSCCU), as well as the Sulfur Recovery Unit (SRU) and its related thermal oxidizer (TOX) after a maintenance shutdown. Some emissions exceeded visible emissions and opacity permit limits as well.

Followup: Yes

Notes: RQ. Refinery letter states that reportable quantities were exceeded for sulfur dioxide, nitrogen oxide, and hydrogen sulfide. Initial refinery letter, plus two additional follow-up reports included in file. Remedial actions: "Maximized steam to flares to mitigation visible emissions...and adjusted feed rates and other process parameters in order to complete startup and stabilize the MSCCU and 3700 SRU units." "A minimal amount of waste gas is expected to be flared during process startup. Currently this activity is permitted for expected losses of criteria pollutants and hydrogen sulfide. Since the loss of propylene is not permitted under startup emissions, but is expected, Valero will request propylene allowances in a future application for a permit modifications. Additionally, we are planning to install flare gas recovery compressors on Flares 1 and 2 in the year 2011. These compressors will have the ability to capture waste gasses generated from startup activities and return them to the refinery fuel gas system."
19.0 pounds

Cause: On 11/19/11, Valero was starting up the Fluid Catalytic Cracking Unit (FCCU) after a power failure tripped the unit. At approximately 2:30 am while start up was in progress, Valero made a notification of startup flaring and that the roof and seals of Tank 67-1 had been damaged resulting in elevated levels of Hydrogen sulfide. Benzene and VOCs being emitted. As a result of the damage of Tank 67-1, hydrogen sulfide and total VOC's including benzene and propylene may have exceeded their respected reportable quantities. Emission calculations for this event are pending and will be included in a subsequent report. Limits for opacity were exceeded in these flares #1 and #2. Liquid vapor pressure on T-67-1 exceeded 11.1 psi.

Followup: No

Notes: Emissions from the refinery flares and Tank 67-1 were lost to the atmosphere and dispersed. Tank Farm Operators moved quickly to inspect Tank 67-1 and activated vapor suppression safety equipment. Operational moves were made to isolate the tank from service and air monitoring was conducted in the tank farm, at the facility fence line, and west of the facility. Supression foam was placed on the tank roof to suppress any vapors and the tank contents were mixed with lower vapor pressure material in order to reduce the overall vapor pressure of the stored liquid. Utility Operators maximized steam to the refinery flares to mitigate visible emissions resulting from the ongoing FCCU startup. NO Ldeq, SPOC report. No follow up.

30, 3700, and1600 Unit Thermal Oxiders, Flares 1 and 2
1600 TOX and Flares 1 and 2
Flares 1 and 2
Cause: Due to multiple equipment high levels during startup of the Gasoline Desulfurizing Unit (GDU), hydrocarbons were introduced into the refinery's sulfur dioxide removal system and to the Sulfur Recovery Units (SRU) feeds resulting in unit upsets. Sulfur dioxide levels at the 1600, 3700 and 30 Unit Thermal Oxidizers were elevated from 3:24 pm on 5/20/11 until 8:00 am on 5/21/11. This caused smoking from the 1600 TOX stack from approximately 3:55 until 4:10 and the unit was shut down during this time. The 3700 and 30 Unit TOXs were also shutdown at approximately 3:40 and 4:13 respectively. Additionally, these process upsets also impacted the refinery's fluid catalytic cracking unit resulting in flaring for portions of this incident.

Followup: Yes

Notes: Valero did not show their limit for SO2, CO, NOx, PM, and VOC in the Thermal Oxidizer and flarecap. No limit was shown for Benzene in the Thermal Oxidizer. No limit was shown for H2S and Propylene in the flarecap. Accurate estimates could not be made. All values are below the total emitted and may be grossly deflated. During the event Valero received an odor complaint and took action to prevent and minimize any public nuisance. Field monitoring did not reveal any detectable quantities of VOCs or sulfur dioxide. Operational moves were made to the sulfur recover plants to shutdown the thermal oxidizers safely. Operators maximized steam to the refinery flares to mitigate visible emissions. During the incident fence-line monitoring was conducted by Valero and there were no detectable concentrations found. The following corrective actions were identified to prevent recurrence of this incident: (1) Modify the startup procedure for the GDU to ensure a shift supervisor monitors the unit radio channel (2) Include in the SRU standing orders that amine upsets be communicated to the shift supervisor and the shift superintendent (3) Modify GDU SOP's to amplify actions required for the amine system (4) Configure a separate console to receive all GDU alarms (5) Implement alarm management to allow high priority alarms to be flagged (6) Consider installing an auto shut off on the amine absorbers bottoms plant wide (7) Consider installing a bypass on the feed to untreated gasoline storage to improve feed control to the GDU during start up (8) Train the SRU operators on the rich DEA flash drum weir configurations. The hydrogen sulfide and sulfur dioxide permitted rates and reportable quantities were exceeded. There were released of nitric oxide, benzene, and VOCs released above reportable quantities. Opacity and visible emission limits were exceeded for flares 1 and 2 and the GRP007 SRU/TOCAP-SRU TO/CAP. The SRU sulfur dioxode concentration limit (250 ppm/ 12 h) for 30 and 1600 Unit TOXs and the EP and WP Fuel Gas hydrogen sulfide (162 ppm/3 h) were also exceeded.
21.0 pounds

Coker LPG line
Cause: Valero had blinded and de-inventoried the Coke LPG line as part of a project to elevate the Prospect Road pipe bridge that connects their East Plant and West Plant. The blinds were removed several days prior to the incident but valves in the pipe system remained closed. Valero believes that gas leaked by one of the valves and accumulated in a section of pipe after the blind had been removed on the West Plant side of the project area thus trapping gas between two closed valves. On the day of the incident, the project operator opened the downstream valve in the pipe bridge that was closest to the FCCU in order to commission a new section of pipe; the upstream valve remained. When the valve was cracked open, gas that had accumulated in the pipe leaked out into the FCCU which was undergoing construction at the time of the incident.

Followup: Yes

Notes: Coker liquified petroleum gas (LPG) which is composed mainly of butenes and propenes was released from pipe openings in the FCCU area and dispersed. Emissions were minimized by isolating the coker LPG line. Valero identified the following corrective actions and target completion dates were identified as a result of the root cause failure analysis of this incident: (1) Issue safety alert on this incident to all personnel (2) Review incident with operators and discuss need for good communications when lining up piping to units (3) Develop a battery limits blind list for the FCCU for use during future turnarounds (4) Develop a battery limits list for Complex III (Crude-Vacuum-Coker units) for use during future turnarounds
158.7 pounds

FLARE: Unspecified flare coming from PSVs on compressors K-14-02A and K-14-02B
Cause: Hydrocarbon flaring was coming from PSVs located on compressors K-14-02A and K-14-02B in the Alkylation unit.

Followup: No

Notes: Fenceline monitoring was conducted to determine impacts to surrounding areas. The results of monitoring are contained in an attachment to the file. The attachment shows no impact.

debutanizer column vent
Cause: On June 4, 2013 at approximately 0930 hrs, the loss of heat medium in the debutanizer column caused controlled venting of sulfur dioxide and propylene.

Followup: No

Notes: A notification was made that a reportable quantity for sulfur dioxide and propylene was exceeded. After further review, it was determined that no reportable quantity has been exceeded resulting from this incident. Emissions associated with this malfunction will be captured in the Title V semiannual deviation report.
83.0 pounds