Firing Systems: Complete Technical Guide

Firing systems: the complete chain that takes the fuel from the storage to the flame of the kiln: the fuel handling, the coal mill, the dosing, the burner, the combustion and the control: the fuel is the energy of the clinker: the specific heat consumption of the plant stands or falls with the firing system: the alternative fuels add the complexity: the firing system is the heart of the burning process: this file is the complete manual from the fuel yard to the burning zone.

The Complete Cement Technical Package (931 files including the books, the courses, the Excel tools and the presentations: $249.99 one-time: instant download via the PayPal payment) includes this firing systems chapter with the fuel tables, the burner drawings, the coal mill data and the firing calculations: the complete library of the cement: this article follows the file from the fuel to the flame.

This page follows the file section by section: the fuels, the storage, the coal grinding, the dosing, the burners, the flame, the combustion control, the alternative fuels and the safety: the burning knowledge of the cement plant in the language of the engineer.

1. The Fuels of the Cement Kiln: The Energy Sources

The kiln can burn a family of fuels: each has its own firing requirements:

• Coal: the classic fuel: the hard coal and the lignite: the calorific value 25-32 MJ/kg (the hard), 8-20 (the lignite): the volatile 20-40%: the ash 5-25%: the moisture: the coal is ground dried and fired: the most widespread:
• Petroleum coke (petcoke): the refinery residue: the 32-35 MJ/kg, the low volatile, the high sulfur (up to 6-8%), the low ash: the mill: the petcoke firing: the sulfur enters the process: the quality of the SO2: the high-temperature ignition: the special burner: the file:
• Natural gas (and the oils): the clean gas: the 35 MJ/Nm: the direct burner flame: the cleanest: the availability of the location: the heavy fuel oil (HFO) the older: the atomization, the pump: the fuel: the economic:
• The alternative fuels (AFR): the RDF, the SRF, the plastics, the tyres, the waste oils, the biomass: the high: the substitution rate (the TS up to 100% in the calciner): the co-processing: the waste-to-energy: the emissions (the metals, the chlorides, the dioxins): the combustion of the AFR: the special: the file: the waste chapter:

THE FUEL SELECTION of the plant: the availability, the price, the supply: the kiln: the multi-fuel capabilities: the burner: the burner is designed for the worst fuel: the basic fuel and the band: the file: the comparison spread of the fuels: the price energy, the net: the firing: the engine: the burning: the file: the selection: the complete: the energy: the “the cheapest the kJ”: the economics:

2. The Fuel Storage and Handling: The Yard

Before the burning, the fuel arrives and is stored:

• The coal yard: the stockpile: the reclaimed: the blended: the coal: the spontaneous combustion (the risk: the pile: the temperature): the monitoring (the internal: the probes: the thermal cameras): the stock rotation: the dust and the water:
• The storage silos: the ground coal: the silos: the explosion, the nitrogen inerting: the low level: the flow: the feeding to the mill: the file: the coal silo design (the mass flow):
• The fuel logistics: the rail, the truck, the ship: the unloading: the conveying: the weigh: the sampling (the calorific value, the moisture: the lab): the fuel receipt: the invoice basis: the typical sample cycling: the file:
• The preparation: the crushing of the coarse coal: the drying (the wet): the blending of the qualities: the magnetic removal (the metal: the mill: the protection): the file: the coal preparation flowsheet:

THE FUEL YARD of the plant: the flowsheet: the arrival, the storage, the preparation, the dispatch to the mill: the safety: the coal dust: the ignition: the file: the yard layout: the safety: the fire walls: the dust suppression: the housekeeping: the file: the “fuel reception” procedures: the quality control: the sample: the file: the receiving: the basis of the fuel bill: the data: the records.

3. The Coal Grinding: The Mill of the Fuel

The ground fuel meets the flame: the coal mill is part of the firing system:

• The purpose: the coal to the fineness: the 2-10% on the 90 micron (the vertical mill: 1-3% typical): the fineness for the combustion (the 90% < 90 mum: the burn-out in the kiln: the volatile: the resistance): the moisture: 1-2%: the mill:
• The types: the vertical roller mill (the coal mill: the modern), the ball mill (the steel: the classic: the abrasion), the HP (hammer) mill: the drying: the hot gas (the kiln exhaust or the burner): the mill fan: the disc:
• The milling parameters: the grinding pressure, the classifier speed, the gas flow: the fineness: the feed size: the moisture: the mill outlet temperature: the file: the mill data sheet:
• The hazardous operation: the mill: the explosion: the coal dust: the lower explosion limit 20-100 g/m3 (depending): the temperature, the CO, the spark, the self-heating: the inerting: N2, CO2: the venting the mill to the safe: the file: the safety chapter of the coal mill: the complete:

THE COAL MILL DESIGN: the throughput (the t/h of the fuel for the kiln: the heat demand: the net CV: the mill capacity: the margin: the fineness: the availability (the 24/24: the spare): the mill: one of the criticalities: the fuel: the standing kilns with the mill: the file: the mill selection: the figures: the drying, the grinding the safety: the start-phase: the file: the complete coal mill chapter.

4. The Dosing of the Fuel: The Weighing and the Feed

The fuel must enter the burner in the exact quantity: the dosing:

• The gravimetric feeding: the belt: the weighing: the silo to the mill: the flow: the measurement: the accuracy: the furnace: the fuel ratio: the control:
• The gas fuel dosing: the flow meters: the pressure: the temperature: the valves: the flow: the filtration: the natural gas skid: the file:
• The oil dosing: the positive: pumps: the flow: the metering: the recirculation: the heater (the HFO: the fuel: the tank: 60-120°C): the atomization: the file:
• The AFR dosing: the alternative fuels: the pellets/floc: the dosers: the screws, the rotary: the pneumatic injection: the heterogeneity: the control: the limestone: the fluctuations: the file: the feeding of the tyres: the systems:

THE DOSING: the control of the fuel: the kiln temperature: the loop: the fuel valve (or the feeder speed) at the signal of the kiln: the response: the fuel: the energy: the setpoint: the file: the control loops of the firing: the primary and the calciner: the fuel ratio (the kiln: the calciner: the 40/60): the control: the NOx: the file: the dosing: the accuracy: the stability: the flame: the quality: the clinker.

5. The Burner Pipe: The Main Burner

The main burner of the kiln: the multi-channel designs:

• The structure: the multi-channel burner: the central fuel lance (the coal: the gas), the annular channels: the primary air (the axial, the swirl), the secondary air (the kiln hood): the flame shaping: the standard: the file:
• The primary air: the 6-10% of the stoichiometric: the high velocity (the 100-300 m/s): the entrainment of the secondary air: the swirl (the recirculation: the flame anchor: the short flame): the file: the primary air options:
• The flame characteristics: the luminous: the length, the shape, the temperature: the “flame anchoring” at the burner tip (the recirculation zone): the ignition: the flame to the clinker (the burning zone: the 1400-1600°C): the flame shaping: the kiln:
• The displacement: the burner position (the axis, the eccentric), the kiln feed: the ingress: the blocking: the coal: The burner: the kiln: the adjustment: the file: the burner adjustment rules:

THE BURNER: the multi-channel: the modern: the coal: low primary air: the fuel flexibility: the flame length: the NOx: the mixing: the file: the burner chapters: the adjustable: the swirler, the axial: the flame: the measurement (the pyrometer: the visions: the flame: the file: the setting: the accuracy: the flame: the “flame as the sculpture”: the file: the main burner of the package.

6. The Calciner: The Second Firing Point

The modern kiln line burns in two places: the kiln and the calciner:

• The purpose: the calciner: the 850-900°C: the decomposition of the limestone: the 60-75% of the calcination happens in the calciner (the kiln does the rest): the fuel ratio: the 40/60: the calciner: the efficiency: the output of the kiln: 2×:
• The types: the in-line calciners (the riser duct), the separate: the air: the kiln exhaust or the tertiary air: the fuel: the calciner: the OUT: the file: the calciner designs:
• The firing in the calciner: the combustion in the gas-solids: the mixing: the retention (the short: 1-3 s): the combustion: the volatile: the fuel: the coal fine (the fast): the AFR in the calciner: the 50-100% substitution: the ideal: the file:
• The CO / the explosions: the calciner: the burning: the O2: the CO: the monitoring: the “mid” the CO: slopping: the file: the calciner control: the temperature: the fuel: the limit: the file: the calciner: the tab: the pulsing: the file: the “second firing” the plant:

THE CALCINER: the modernization: the “hot” of the dry process: the calciner: the burning: the kiln share: the fuel types: the calciner: the string: the file: the calciner chapter: the design: the O2, the temperature, the residue: the firing system: the TWO: the file: the complete: the secondary combustion: the calciner: the heart of the new kiln: the file: the burning: the second: the system.

7. The Combustion: The Chemistry of the Fire

The combustion in the kiln: the chemistry and the control of the fire:

• The stoichiometry: the combustion: the C + O2: the requirements: the air per kg of the fuel: the air factor (lambda): the 1.05-1.10: the O2 at the kiln exit: the 1-3%: the perfect: the file:
• The volatiles: the coal volatile: the combustion: the gas: the char: the ignition: the volatile release: the flame: the rapid: the file: the volatile: the flame cone:
• The burnout: the char/burn-out: the fine coal: the residence: the temperature: the “unburnt”: the coal: the ash: the Bayer: the file: the “burn-out”: the calculation:
• The NOx: the emissions: the thermal NOx (the high temperature): the fuel NOx (the volatile nitrogen): the fast: the NOx: the 300-800 mg/m3: the BREF: the file: the NOx reduction: the “staged” combustion: the calciner: the SNCR (the urea): the file:
• the SOx and the chlorides: the fuel sulfur: the SO2: the raw: the chlorine: the cycles: the file: the emission control: the firing system: the fuel: the SO3: the file:

THE FLAME CHEMISTRY: the O2, the CO, the NOx: the file: the “combustion triangle”: the temperature: the time: the turbulence: the file: the flame: the burning: the optimized: the fuel-bound: the elementary: the file: the combustion: the calculations: the air/fuel: the file: the sample: the composite: the NOx: the file: the chapter: the file and the flame: the chemistry: the technical: the file of the file: the chemistry: the fire.

8. The Safety of the Firing System

The firing equipment: the hazardous: the safety systems:

• The coal: the dust explosions: the limits: the housekeeping: the dust: the ignition: the sources: the discharge (the static), the heat (the friction, the fire), the sparks: the file: the ATEX: the zones: the equipment: the standard:
• The mill safety: the CO monitors: the oxygen: the temperature: the inerting (the N2/CO2): the deluge: the trip: the fire fighting: the file: the mill safety: the interlocks:
• The burner safety: the gas: the protection: the pressure, the minimum, the valves: the UV: the flame detector: the purge: the gas train: the PED: the standards: the file: the gas safety:
• The hot surfaces: the kiln: the burner: the radiation: the protective: the housing: the “the hot” the 200°C: the procedures: the oil: the spray: the fire hazard: the file: the HAZID: the file:
• The emergency: the procedures: the fire: the evacuation: the checklists: the fire marshal: the file: the drills: the file: the complete safety chapter: the file:

THE SAFETY: the attitude of the industry: the coal-fired plants: the century of the practice: the rules: the “hard rules”: the file: the protocol: the documentation: the audit: the culture: the file: the OHS: the responsibilities: the file: the safety: the “stop: think: check”: the file: the training: the file: the complete firing safety: the engine of the trust: the file: the single: the explosions: the zero: the file of the culture.

9. The NOx and the Emissions of the Firing

The firing system is the source of the atmospheric emissions: the control:

• The NOx formation: the thermal (the >1300°C: the Zeldovich), the fuel, the prompt: the kiln flame: the 1400-1650°C: the curtain: the file: the mechanisms:
• The primary measures: the low-NOx burners (the staging: the deflect: the flame): the calciner staging: the stable: the raw meal (the ON): the file: the combination:
• The secondary (SNCR/SCR): the ammonia/urea injection at the temperature: the SN: the 850-1000°C: the slip: the usage: the SCR (the catalyst: the NOx removal 70-90): the dust and the catalyst: the file: the comparison:
• The SO2: the fuel sulfur: the raw sulfur: the SO2: 10-50% of the sulfur: the process: the alsage: the SO scrubbers (the dry/wet): the file:
• The metals / dioxins (the AFR): the alternative fuels: the metals: the cycle: the stack: the TEQ: the file: the emission: the chapter: the AF: the limits:

THE FIRE & THE ENVIRONMENT: the plant: the stack: the emissions: the firing: the design: the compliance: the NOx limit: the burner: the calciner: the SNCR: the file: the emission: the complete: the firing: the “green”: the process: the file: the filing: the NOx: the SO: the TRD: the file: the combustion: the clean: the file: the emissions: the fire: the chapter: the regulation: the plant: the stack: the environmental: the complete: the firing.

10. The Optimization of the Firing: the Heat Consumption

The firing: the energy: the specific heat consumption: the optimization:

• The heat balance: the clinker: the 3,100-3,500 kJ/kg: the theoretical and the losses: the fuel: the flame: the file: the heat balance: the workbook:
• The optimization measures: the primary air reduction (the burner: the modern: the 6-8%): the stable flame: the preheating: the air ratio: the leakage reduction: the refractory: the file:
• The fuel quality: the calorific: the moisture: the ash: the grinding fineness: the CV: the fuel blends: the file: the fuel management: the purchasing: the file:
• The data: the thermal: the consumption: the kWh: the kiln production: the tracking: the file: the spreadsheet: the daily: the file:

THE OPTIMIZATION: the file: the “kWh” “the thermal tuning”: the firing: the fuel: the clinker: the cost: the file: the audit: the improvements: the coal: the file: the “rational”: the file: the primary: the file: the burning: the window: the file: the plant: the producer: the optimization: the file: the temperature: the constant: the compute: the file: the life of the works: the carbon: the file: the file: the burning: the save: the file: the optimization: the energy.

11. The Troubleshooting of the Firing Systems

The problems of the firing and the answers of the file:

• The flame instability: the coal variation (the fines: the moisture), the burner setting, the primary: the drive: the file:
• The low flame temperature: the fuel quality: the air: the mixing: the flame: the check: the file:
• The CO in the exit: the incomplete: the burner: the air: the calc: the file: the CO: the explosions: the file:
• The high fuel consumption: the process: the losses: the false air: the moisture: the file: the thermo:
• The NOx too high: the flame: the temper: the urea: the file: the NOx: the tuning:
• The clogging / the coke: the kiln: the “the block” the production: the file: the procedures:

THE DIAGNOSTIC: the firing: the symptom: the file: the table: the measurement: the file: the troubleshooting: the fuel: the flame: the WO: the file: the burners: the maintenance: the file: the case: the file: the chapter: the honest: the answers: the file: the firing: the problems: the solutions: the file: the complete: the troubleshooting: the file: the plant.

12. The Alternative Fuels and the Co-Processing: The Firing of the Waste

The modern firing systems burn more than the coal: the alternative fuels chapter of the file:

• The family of the AFR: the RDF/SRF (the municipal and the commercial), the tyres, the plastics, the waste oils, the solvents, the biomass, the meat-and-bone meal: the calorific value 10–30 MJ/kg: the composition varies: the file: the AFR data table:
• The effects on the firing: the moisture (10–30%), the ash, the chlorine, the metals, the sulfur: the flame: the “the pre-combustion” of the dry fractions: the calciner is the favorite point (the 850–900°C, the 2–4 seconds, the high residence of the gas, the “the SO2” and the “the NOx” capture): the kiln main flame limits the use (the flame length, the clinker quality, the refractory): the file: the feeding points diagram:
• The feeding systems: the shredding, the fluff, the pellets: the dosing screws, the pneumatic injection, the chutes and the pre-combustion chambers for the coarse tyres: the safety: the fire in the storage, the gas: the file: the feeding equipment chapter:
• The substitution rate (TSR): the typical plants 20–70% of the thermal energy: the leaders above 90%: the calciner takes the 60–100% of its fuel from the waste: the file: the TSR economics: the fuel cost of the clinker:
• The emissions of the AFR: the chlorine cycles, the metals, the dioxins: the “the combustion quality” rules: the stable high temperature, the O2, the retention: the file: the emission chapter of the AFR:

THE CO-PROCESSING is the double win of the cement industry: the waste of the society is the energy of the clinker: the firing system must be designed for the substitution: the burner, the calciner, the feed points and the gas cleaning: the file: the complete chapter: the waste: the fuel: the fire: the emissions: the plants of the world: the practice: the professional: the cement: the complete: the alternative fuels in the firing: the file of the package: the modern: the kiln: the 21st century: the firing: the sustainable: the file: the numbers: the engineer: the substitution: the fuel: the complete.

13. The Startup, the Shutdown and the Abnormal States of the Firing

The firing system operation is not only the steady state: the transitions demand their own craft: the file: the complete procedure:

• The cold start: the refractory heat-up: the ramp of the fuel: the ignition of the main burner only after the stack flow: the purge: the file: the startup sequence:
• The heat-up curves: the refractories: the brick expansion: the thermal shock: the heat-up rate for the first 24–36 hours: the file: the curve: the thermocouples: the monitoring:
• The mill start: the coal mill first or in parallel: the fuel buffer: the silo levels: the mill availability: the file: the sequence and the interlocks:
• The shutdown: the fuel off, the kiln rotating for the cooldown: the purge: the settling: the file: the shutdown procedure:
• The abnormal: the kiln trip, the flame loss, the CO high: the emergency fuel cut: the sequence: the file: the emergency response table: the drills:

THE TRANSIENTS: the know-how of the experienced: the file: the graphs of the startup: the failure cases: the electricity outage: the restart: the kiln: the refractory: the “the firing” the abnormal: the fast: the file: the professionalism: the cement: the plant: the procedure: the discipline: the file: the firing: the complete.

14. The Instrumentation and the Controls of the Firing System

The firing system runs on the measurements: the instrument chapter of the file:

• The flow and the weight: the coal weigh feeders, the gas flow meters, the oil meters: the accuracy of the fuel accounting: the bed: the file: the metering: the calibration:
• The temperature: the flame (the pyrometers), the kiln shell (the scanner), the burner (the carbide), the mill inlet/outlet: the thermography of the kiln: the file: the temperature instrumentation:
• The pressure and the flow: the primary air pressure, the swirl register position, the hood pressure, the secondary air: the burner data of the control: the file: the P&ID of the firing:
• The gas analysis: the O2, the CO, the NOx at the kiln exit and the upper preheater: the combustion tuning: the file: the analyzer positioning: the calibration: the safety CO:
• The control: the kiln fuel control loop, the calciner loop, the O2 loop: the ratio: the DCS: the file: the control philosophy: the tuning of the loops:

THE INSTRUMENTS: the brain of the firing: without the meters the boiler is the guesswork: the file: the worksheets: the sensor pallet: for the kiln and the calciner: the file: the loops: the control: the setpoints: the calorific input: the stable: the file: the firing: the instrumentation: the complete: the professional: the cement: the file: the instruments: the flame: the control: the process: the number: the accurate: the file.

15. The Energy and the Efficiency of the Firing: The Heat of the Clinker

The firing system is the energy gate of the plant: the specific heat consumption of the clinker sits between the flame and the process:

• The specific heat consumption: the 3,100–3,500 kJ/kg of the clinker for the dry process: the firing, the preheater, the cooler losses: the file: the heat consumption of the plant:
• The heat losses: the exit gas, the radiation, the false air, the unburned fuel, the cooler losses: the firing: the analysis: the file: the heat balance worksheet:
• The optimization levers: the O2 reduction, the stable kiln, the primary air reduction, the waste heat recovery: the firing: the energy: the file: the energy audit of the kiln:
• The fuel mix economic: the cheapest fuel mix, the alternatives: the price per GJ: the firing consumes the competitive: the file: the fuel economics:
• The carbon: the fuel and the process CO2: the ETS, the carbon: the fuel optimization and the low-carbon fuel: the file: the CO2 of the firing:

THE ENERGY: the firing is the cost center of the plant: the fuel is the largest or second budget line: the file: the energy chapter: the numbers of the plant: the improved firing: the money and the emissions of the same investment: the file: the fire: the cost: the carbon: the complete: the energy: the professional: the filing: the cement: the plant: the file: the combustion: the saving: the fuel: the file of the package.

16. Frequently Asked Questions on the Firing Systems

What is the “primary air” percent of the burner?

The 6-10% of the total air: the modern low-NOx burners: the transport and the shaping of the coal: the rest (the 90-94%) the secondary: the entrained by the flame: the primary: the swirl: the file: the burner data: the low-primary: the improvement: the heat: the file: the answer: the 6-10%.

Can the kiln run on the alternative fuels only?

In the calciner: up to the 60-100% of the fuel: the kiln main burner: the classical: the limitations (the flame length: the clinker: the heat: the ash: the metal: the chloride): the 70-90% of the total is the achievable: the file: the AFR: the substitution: the NOx: the file: the plant: the practice: the answer: the often yes: the carefully: the file.

Why should my coal be ground so fine?

The combustion: the burn-out: the flame: the 2-10% +90 micron: the large: the “unburnt” (the CO: the ash): the fines: the volatiles: the flame: the mill: the energy: the file: the balance: the fineness: the combustion: the file: the answer: the flame efficiency.

The NOx of the kiln is too high: the primary measures vs the SNCR?

The primary: the burners, the calc, the fuel: the NOx: the 20-60% (the invest): the SNCR: the 30-70% further: the ammonia: the carry: the slip: the SCR: the ~95%: the cost: the file: the decision: the measures: the chain: the file: the hierarchy: the primary: the optimize: the SNCR: the answer: the primary is the first, the SNCR the supplement.

The firing systems of this package: the include the Excel tools?

The package: the combustion calculation workbook (the air: the fuel: the flame temps), the heat balance of the kiln, the coal mill sizing, the burner: the workbook: the 931 files: the firing: the entire library: the $249.99: the instant: the file: the Excel: the tools: the answer: yes.

17. The Conclusion of the Firing

The firing systems: the heart of the burning: the fuel: the storage, the milling, the dosing, the burner, the flame: the calciner: the safety: the emissions: the optimization: the whole: the file: the complete: the engineer: the fire: the plant: the burning zone: the clinker: the energy: the file: the knowledge: the package: the ignition: the cement: the professional: the library: the file: the firing: the firing: the cement: the complete: the knowledge: the package.

The Complete Cement Technical Package (931 files: $249.99 one-time: instant download via the PayPal) includes the firing systems with the fuel tables, the burners, the coal mills, the safety and the Excel tools: the complete library of the cement: the kiln, the firing, the mills: the one-time: the professional: the engineer: the file: the follow: the same: the office: the plant: the download: the instant: the PayPal: the button: the knowledge of the 931: the library: the buy: the cement: the professional: the fire: the package.

This file is part of the Complete Cement Technical Package (931 files) available from cementequipment.org. Respective rights holders; library copy for the licensed single user.