Kiln inlet temp drop due to following reason
1. Heavy coating at kiln inlet – check temp. profile in kiln calcination zone ( kiln inlet to 10. mtr )
2. Can having co formation at kiln inlet .- To avoid co formation for it.
3. If preheater fan flow is less and cooler vent flow is high than say burning zone become short and all zone shifting toward kiln hood . Which indicat by cooler vent temp. , high clinker temp and flame become short and wide and kiln inlet temp less.
4.There may be possibilities that material which enters in the Calciner, part of material directly falling at Kiln inlet. Reason may be whatever so. 1. Please check dispersion plate of material entering in Calciner, check the angle and shape of dispersion plate. 2. Fuel variation also may be one of the reason because, Raw meal feeding and coal feeding are generally near by. If you using Screw conveyor or Rotory air lock for coal feeding, there may be chance of wear and gape increased in system and it lead to fuel flucuation. Some time if veocity of kiln feed hood area decreased by area increase at feed hood and kiln inlet due to no deposition of any coating, that also lead to drop out some of material in Kiln inlet and reduce the Kiln inlet temperature. Leakage in the preheater system or downcomer duct expansion joints also one of the reason to drop out material. One posibility may be there that Materia deposition at band portion of caciner or cyclone suddenly rush also reduce the temperature at Kiln inlet. Please note that, whenever there is material falling directly there are definitely Calciner temperature will shut up and you are forced to reduce the Calciner coal. Please observe this phenomina also.