Cement kilns are 60-100 m rotating cylinders that form clinker at 1450 C. They burn 500-3000 t/day of coke, tire chips, refuse-derived fuel (RDF) and solvent waste. NFPA 85 provides calorimetric calculations and fuel-management rules.
Cement Process
- Calcination: 900 C CaCO3 -> CaO
- Clinker: 1450 C C3S C2S formation
- Cooler: Grate 100 C cooling
- Kiln rotation: 2-4 rpm
- Capacity: 3000-10000 t/day
Alternative Fuels
- RDF: 15-20 MJ/kg
- Tire chip: 32 MJ/kg
- Solvent: 25-35 MJ/kg
- Biomass: 14-18 MJ/kg
- Petcoke: 32 MJ/kg historic
NFPA 85 Fuel Management
- Feed interlock: Flame scanner required
- Purge: Restart 5 volumes
- CO monitor: 2 percent alarm
- Pressure sweep: -5 mmWg negative
- Trip: High temperature 1550 C
Downstream Fire Protection
- Cable tray: Sprinkler 12.2 L/min/m2
- Fuel feed silo: Spark detection
- Coal mill: CO monitor + inert
- ESP: Fly ash CO blast
- Bag filter: Refractory hot gas
Turkish Cement Sector
- Akcansa Canakkale: 7.5 Mt/y
- Oyak Cement Bolu: 2.3 Mt/y
- Limak Cement: 10 plants
- Cimsa Mersin: White cement
- Total: 70+ Mt/y Turkey capacity
Kilns with SprinkCalc
SprinkCalc sizes cement-kiln RDF feed, 2 percent CO alarm, coal-mill inerting, cable-tray sprinkler 12.2 L/min/m2 and NFPA 85 interlock.
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Sources & Further Reading
NFPA 85, NFPA 664, NFPA 654, EN 197, CEN TC 51. NFPA 85 Boiler and Combustion Systems.