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|State Police #||13-01697|
|Pollutant||Duration||Point Source||Greenhouse Gas||Criteria Pollutant||Ozone forming chemical||Amount of Release|
|Carbon Monoxide||3h||OL-5 Elevated Flare, FE-101||NO||YES||NO||2,101.7 pounds|
|NOx||3h||OL-5 Elevated Flare, FE-101||NO||NO||YES||386.3 pounds|
|Particulate Matter||3h||OL-5 Elevated Flare, FE-101||NO||YES||NO||681.6 pounds|
|Volatile Organic Compounds (VOCs)||3h||OL-5 Elevated Flare, FE-101||NO||NO||YES||1,204.9 pounds|
|1,3-Butadiene||3h||OL-5 Elevated Flare, FE-101||NO||NO||YES||32.5 pounds|
|Benzene||3h||OL-5 Elevated Flare, FE-101||NO||NO||YES||29.7 pounds|
|Ethylbenzene||3h||OL-5 Elevated Flare, FE-101||NO||NO||YES||2.7 pounds|
|Toluene||3h||OL-5 Elevated Flare, FE-101||NO||NO||NO||20.9 pounds|
|Xylene||3h||OL-5 Elevated Flare, FE-101||NO||NO||NO||10.8 pounds|
Accident Classified As: Below Reportable Quantity (BRQ)
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.
This incident was not preventable by Shell. The malfunction of the surface condenser level transmitter was unexpected.
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.