TL;DR
A calciner fuel trip causes rapid drop in calcination temperature. Identify whether the trip was a fuel supply failure or a burner fault, then restore fuel safely following the light-off procedure.
What you might see
- calciner outlet temperature dropping rapidly
- fuel flow meter reading zero
- calcination degree alarm active
- kiln inlet temperature rising
Likely causes
Fuel supply valve closed by an interlock due to low pressure or a safety system actuation
Fuel filter plugged reducing fuel flow below the burner minimum
Calciner burner flame detection failure causing a safety shutdown
Fuel line pressure below the minimum required for atomization
Required tools
- DCS access for alarm history
- Pressure gauge for fuel line
- Replacement fuel filter element
- Flame scanner cleaning kit
Safety first
- Never supply fuel to a hot calciner without confirmed ignition. Unburned fuel accumulation in a hot chamber is an explosion hazard.
- Thermal radiation from the calciner casing. Use appropriate PPE when working near the calciner body.
Procedure
- 1
Check the DCS alarm log for the root-cause trip signal. Identify whether it was a fuel pressure trip, a flame detection trip, or an emergency stop.[1]
- 2
Do not attempt to restart fuel to the calciner before identifying the trip cause.
- 3
Check the fuel supply pressure upstream of the calciner burner valve.[1]
- 4
Inspect the fuel filter differential pressure. Replace the filter element if the differential is above the trip setpoint.
- 5
If the trip was a flame detection fault, inspect the flame scanner for fouling or misalignment. Clean the scanner lens.
- 6
Follow the calciner light-off procedure to re-establish fuel and ignition in the correct sequence.
Warning: Never supply fuel to the calciner before confirming all combustion safety interlocks are healthy. An unlit fuel supply into a hot chamber is an explosion risk. - 7
After re-ignition, ramp the calciner temperature back to the target at the approved rate to avoid thermal shock to the refractory.
Sources
FLSmidth FLSmidth ILC / SLC-D Preheater Tower / Calciner general technical documentation, FLSmidth
FLSmidth calciner burner and fuel system operation documentation (general)
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