Temperature Overshooting in Fired Heater

[Alaaeldin55]

Dear Colleagues,

We are currently investigating an incident involving one of our multiple convection fired heaters.

During this event, the process outlet temperature exceeded the design limits for both the heater coil and the outlet process associated piping.

While we initially considered potential causes such as low process flow, excessive heat input, or malfunctioning fuel control valves, a sharp increase in process flow during the overshoot event makes these less likely.

A plausible explanation is that one of the two tube coil heating passes within the heater may have become partially blocked. This blockage could have led to localized overheating, and once the blockage was cleared, the increased flow through the previously restricted pass caused a sudden spike in outlet temperature.

Unfortunately, the absence of temperature and flow sensors on individual heating passes limits our ability to directly confirm this hypothesis.

We seek your expert advice on the credibility of this scenario and potential strategies to ensure the safe operation of the heater.

Thank you for your valuable insights.

 

[LittleInch]

Well only you have knowledge of what happened in terms of temperature, temp rise rate, flow, heat input (gas?) flow rate, did the lining overheat or supply radiant heat at low flow which added to input heat? Fluid being heated? Why would it block under heat?

If you don't supply useful information you won't get good responses.