Flash Fire from Liquid Phase Heat Transfer Unit
Effective Date: 9/22/1972
Minerals Management Service
Gulf of Mexico OCS Region
Notice No. 001
September 22, 1972
A flash fire occurred in the production facilities of a producing platform inOCS waters directly resulting from the ignition of fluid from the heat transferunit.
The liquid phase heat transfer system was being used for heating oil toseparate water through a chemical-electric treater. It was also to be used asthe heating medium for the glycol system to separate water from gas but thatsystem was not in operation.
The incident occurred as the production facilities were being put back intoservice after being shut-down by the low pressure sensor on the departing oilflowline. Overheating of the heat transfer fluid was caused by the chemicalcirculating pumps not operating while the main burner valve was in operation.This resulted in a rapid pressure increase and expansion of the heat transferfluid which ruptured the top of the expansion tank allowing the fluid to spillover the heater and deck area. Ignition of the fluid occurred shortlyafterwards.
Results of the investigation indicate that the following steps should betaken in order to prevent this type of failure:
1. Heat transfer fluid expansion tanks should be equipped with a largesecondary relief valve which should be operationally tested monthly and beforeeach start-up.
2. Control mechanism should be installed to prevent the main burner fuelvalve from operating when the chemical circulating pumps are not operating.
3. Expansion tanks should be pressure-rated vessels constructed to withstandpressures exceeding the normal operating pressure range.
4. Heat sensors should be installed immediately downstream of the firebox andbe in continuous service.
[signed] Robert F. Evans
Area Oil and Gas Supervisor