Release of Hydrocarbons Mixture from a Pressure Vessel
A release of contents of a pressure vessel occurred when a longitudinal weld tore open. The vessel had been shut down and had just been put into use again when the incident occurred.The gas mixture contained hydrocarbons with 30% hydrogen. It has reached its working pressure of 31 bar, but was only at -26 degrees C, instead of the working temperature of -73 degrees C, no liquid was present.An investigation found a crack, 1.6 metres long, had formed near the upper end of the weld.
Event Date
July 6, 1996
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
vessel
Storage/Process Medium
Location Type
Location description
Industrial Area
Pre-event Summary
.
Currency
Lessons Learned
Lessons Learned
The following recommendations were made:1.All vessels of similar construction to be tested for incipient cracks on the inner surface by using a dye penetration test.2.If the interior is inaccessible, welds and impact zones are to be tested by ultrasonic methods. Procedures were not developed for many operations, including obtaining temperature data from outside field panels underneath the reactors.3.Poor Process Hazard Analysis, that did not even reflect the actual equipment and instrumentation used in the process.
Event Nature
Emergency Action
Unknown
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category