September, 1998

199825SepAll DayLongford 1998 - Incident SummaryDeethaniser Reboiler Catastrophic FailureLessons:Competency,Emergency Preparedness,Management of Change,Operating Procedures,Risk AssessmentIndustry:Gas ProcessingLanguage:EN Origin: IChemE SLP Equipment:Shell & TubeDocument Type:SummaryTopics:Ageing,Alarm Management,HAZOP

Summary

A gas processing plant was taken off-line following a major upset. A few hours later, the rich oil deethaniser reboiler had become intensely cold and failed catastrophically when warm lean oil was re-introduced during restart.

The failure released more than 10 tonnes (22,000 lb) of hydrocarbon vapour to atmosphere. The vapour cloud drifted 170 m (560 ft) to a set of fired heaters and ignited. The flame front from the resulting deflagration burned through the vapour cloud without causing an explosion. When it reached the ruptured exchanger, a fierce jet fire developed beneath an elevated piperack junction and flame impingement caused 3 more leaks. The resulting fire burned for more than 2 days. Two employees were killed and eight more were injured.

Supplies of natural gas to domestic and industrial users throughout the State of Victoria were halted for more than 2 weeks, causing substantial losses to industry and massive inconvenience to people in their homes.

Basic Cause:
Brittle fracture of the deethaniser reboiler channel end due to intense low temperature (-42 oC vs 100 oC in normal operation).

Origin

IChemE SLPSafety & Loss Prevention Special Interest Group

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