Electric tank heaters present several possible dangers in process heating applications. Recent incidents include one at a manufacturing plant and another at an oil-and-gas processing facility.
The manufacturing facility incident occurred on the hydraulic oil storage tank similar to thousands in use all over the world. Because of the commonality of these systems, and the prolific use of electric tank immersion heaters, it is important to be aware of the potential danger associated with this setup.
The other explosion occurred at an oil-and-gas processing facility outside of Pittsburgh. There, a fire broke out at a complex of three storage tanks, each about 25' tall and 8' wide.
At the facility, the natural gas was pressurized within the tanks and moved along a pipeline to a processing plant, leaving behind a “briny fluid” made up of liquid hydrocarbon waste called condensate. The tank's electric heaters are designed to keep the liquid mixture from freezing.
The local fire chief explained that the tank designed to hold the liquid apparently was empty or nearly empty but contained gas vapors. When the liquid mixture is low, the heating element is designed to shut off. But in this case, the electric heater continued to operate, eventually warming the vapors to combustible levels, setting off the explosion.
Seeing such disasters, it becomes apparent that any electric tank heaters should be reviewed for design and installation issues that can lead to explosions so facilities can take action to avoid an incident.
How would someone know that they might have a problem? In this article, several key electric tank heater design and installation issues - that, if left unchecked, could lead to fires or explosions - will be reviewed.