Leak from a hydrogen compressor

The incident occurred at a hydrogen compression facility, due to a leaking connection. The hydrogen was released through the pressure relief inertised line. It ignited when mixing with air at the exit of the line.
The system was brought into a safe operating condition, the company the fire brigade, the superiors and the crisis team were informed. The flame was extinguished by switching off the system or the hydrogen supply.

The INITIATING CAUSE was a leak on a fitting of a pressure relief device.
By analysis the corrective measures taken, the ROOT CAUSE could be possibly assigned to shortcoming in the procedures related to inspections of the joints and to the design of the venting lines (probably to avoid mixing hydrogen and air in the vent duct).

fitting,
PRD,
vent line

ZEMA reports that the regeneration process was running under normal conditions.
A similar events had happened September 25, 2017, when a flame broke out on a relief line in the area of the low-temperature adsorber used for the hydrogen purification.

DESCRIPTION OF THE UNIT
It appears that the affected compressor was part of a system containing also a regeneration step. Unclear is of it relates to the regeneration of a catalyst by means of hydrogen or to purification of hydrogen.

No injury, no material damage: the discharge line was constructed according to internal standards and was not damaged by the fire.

The area was cordoned off and the plant was shut down.
After that, the relief line was monitored by an infrared thermometer and the line was briefly cooled with water.

• The purging of all identical relief lines was improved
• All valves were replaced
• The procedure managing the inspection of the valves was modified by increasing inspection frequency
• The Regeneration process procedure was extended by including leak testing involving an approval by a supervisor.