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|State Police #||13-05721|
|Pollutant||Duration||Point Source||Greenhouse Gas||Criteria Pollutant||Ozone forming chemical||Amount of Release|
|Hydrogen Sulfide||2h||RCCU Elevated Flare||NO||NO||NO||BRQ|
|Carbon Monoxide||2h||RCCU Elevated Flare||NO||YES||NO||10.1 pounds|
|Nitric Oxide||2h||RCCU Elevated Flare||NO||YES||NO||1.9 pounds|
|Particulate Matter||2h||RCCU Elevated Flare||NO||YES||NO||0.4 pounds|
|Sulfur Dioxide||2h||RCCU Elevated Flare||NO||YES||NO||2.1 pounds|
|Volatile Organic Compounds (VOCs)||2h||RCCU Elevated Flare||NO||NO||YES||0.9 pounds|
Accident Classified As: Below Reportable Quantity (BRQ)
On December 23, 2013, the Residual Catalytic Cracking Unit (RCCU) Elevated Flare exceeded its 162 ppm three-hour rolling average limit for hydrogen sulfide. The monitoring capabilities of the hydrogen sulfide analyzer at the RCCU Elevated Flare were exceeded as the hydrogen sulfide to the flare continued to increase. Several contributing factors were identified. One of these factors was that the cold weather was affecting some of the valve bodies by allowing small quantities of H2S to leak through a closed valve during lower ambient temperatures. In addition, it was found that the RCCU flare knock out drum and the maintenance drop out drum were contaminated with H2S as a result of recent shutdown activities. This event did not result in an emergency condition. There were no fatalities, injuries, or road closures.
Immediately, Operations began a systematic search for the sources of H2S routed to the flare. This search identifies all potential H2S intrusion points with the RCCU and RGHT Units, and prioritized those most likely contributing to the elevated H2S in the Flare system. Flushes the RCCU Elevated flare knock out drum and the maintenance drop out drum. Upgraded valves HV4346 a IV one-piece metal seats to class VI three-piece metal Teflon seats. Unit rate increases were delayed and unit feed rates were maintained during the duration of the incident. To prevent recurrences, the refinery will (1) evaluate the need to upgrade/replace additional RV and HIC valves that are routed to the RCCU Elevated Flare header in order to prevent leakage during cold weather; and (2) evaluate the need to apply weather shields and/or steam lances to valves affect by cold weather. The report does not mention when the refinery will implement these preventative measures.