Summary of incident
In April 2024, a regeneration gas heater ruptured at a gas processing plant when an electrically heated regeneration vessel overheated. Regeneration gas heaters are commonly used in the regeneration of molecular sieve dehydrators with the recirculation of dried natural gas heated to 250 degrees Celsius throughout a dehydrating purge cycle.
The initiation of manual operating mode together with an operator misaligning a valve configuration prevented the flow of natural gas, which developed a ‘no flow’ gas scenario in the regeneration circuit.
Additionally, a faulty thermocouple downstream of the vessel negated the over-temperature interlock.
An electrical heating element bundle overheated the vessel to the point of ductile failure, resulting in catastrophic failure of the regeneration heater vessel and a localised flash fire.
