Release from a Hydrogen Line to the Desulfurization Unit of a Refinery
A sudden failure occurs on a hydrogen line of a refinery desulfurization unit. The equipment is located between a hydrogen compressor and its overpressure protection valve. It is isolated automatically.The bursting of the pipe is due to its corrosion: a thick loss of thickness extends over 300 mm. The presence of a bend at a low point on a line without circulation led to the accumulation of deposits initiating a corrosion mechanism.The operator modifies the layout of the piping to avoid low points. It performs thickness checks on lines identified as sensitive.The operator learns from the accident:Valve inlet lines are similar to dead arms and should be considered as such when establishing inspection plans. They must be the subject of the corresponding enhanced controls;these lines should be as short as possible and self-draining.
Event Date
April 1, 2006
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
Immediate cause is due to corrosion which reduced the stress-bearing wall thickness of the pipe. The root cause is found in non optimal design and identification of weak points
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
hydrogen line of a refinery desulfurization unit
Storage/Process Medium
Location Type
Location description
Industrial Area
Pre-event Summary
The failed pipe was at the bottom of the system, without self-draining mechanism.
Lessons Learned
Lessons Learned
The lessons learned from the accident are:1.Valve inlet lines are similar to dead arms and should be considered as such when establishing inspection plans. They must be the subject of the corresponding enhanced controls;2.these lines should be as short as possible and self-draining.
Event Nature
Emergency Action
The pipe was isolated automatically.
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
ARIA data base
event no. 51671