An industrial heater used to heat a naphtha-hydrogen mixture developed a small leak in one of its finned tubes. The leak resulted in a 2-ft long torch flame, which was eventually noticed by an employee. Upon discovering the fire, the hydrotreater was shut down by cutting off the flow of naphtha and the flow of fuel to the burners in the heater. The hydrogen flow was maintained in order to cool and sweep the reactor during the shutdown operation.
The torch flame appeared to diminish significantly while only the hydrogen was flowing. However, molten metal dripping from the heater indicated that a much more severe fire was still in progress. The fire was eventually controlled by reducing the hydrogen flow and injecting steam into the heater. Inspection of the damaged heater revealed that the fire had completely melted 12-ft long sections of 32 finned tubes.
- Heating Equipment
- Industrial Heater
This incident illustrates how a hydrogen fire which appears to be 'quite small' can actually be only the visible portion of a much larger fire. Observation alone is not a reliable technique for detecting pure hydrogen fires and/or assessing their severity.