|About the Database
|LDEQ Accident Number
|Amount of Release
|HCU Elevated Flare (EPN 4-84)
|Cause: On April 28, 2011 at 0717, Motiva's Hydrogen Unit experienced a release to the atmosphere from a loss of pilot flame at HCU Elevated Flare (EPN 4-84).
Prior to the release, Motiva's Hydrogen Unit was in the process of restarting the unit after a planned maintenance activity. As part of the unit re-start procedure, operators are required to purge process vessels with steam and nitrogen to the HCU flare header in order to remove any excess oxygen that may have been entrained in the process vessels and/or piping as a result of maintenance activities. Following an investigation of this incident, Motiva has determined that steam was introduced into the Hydrogen plant process too quickly, causing a spike in nitrogen to the HCU flare which extinguished the flare pilots for approximately 6 minutes.
Notes: Operations responded immediately to the pilot loss alarm by reducing the steam rate to the flare header and re-lighting the flare pilots. In order to prevent a similar incident in the future, a step will be added to the unit startup procedure to slowly increase the steam purge rate in 50lb increments and hold each rate constant for 30 minutes before increasing to the next flow rate.