Burner Calculation: Calculations & Excel Sheet
The burner calculation file is the working spreadsheet of the kiln engineer: the single page where the numbers of the burner come together: the fuel flow, the primary air, the velocities, the momentum, the flame length and the nozzle openings: the design calculations that turn the burner from a piece of pipe into a tuned instrument of the burning zone.
The burner of a rotary kiln appears a simple tube at the kiln hood, but its numbers govern the most expensive seconds of the process: the flame shape controls the heat transfer of the burning zone, the clinker quality, the refractory life and the fuel consumption: the incorrect burner settings waste the kilns’ million calories every day: the calculation file gathers the formulas and the reference values that every plant recalculates after every repair of the burner and with every change of fuel: the burner, calculated.
The Complete Cement Technical Package (931 files: the books, the courses, the Excel tools and the presentations: $249.99 one-time: instant download through the secure PayPal payment) delivers this calculation tool with the burner collection: the burner Bible, the burner sessions, the flame shape sections: this article walks the file: the inputs, the formulas, the examples, the interpretation and the practice of the burner calculations in the plants.
1. The Burner Basics: What the Calculation File Computes
The burner calculation file standardizes the numbers that every kiln team knows by heart and recalculates by necessity:
- The fuel flow: the consumption of fuel in tons per hour or cubic meters, derived from the clinker production, the kiln heat requirement and the fuel net calorific value: the file starts from the daily production plan and returns the fuel demand;
- The primary air: the air jetted through the burner: the axial air, the swirl air and the central air: its percentage of the total combustion air and its velocity: the driver of the flame shape and the momentum;
- The momentum: the force of the primary air jet: the momentum governs the flame length and the penetration of the flame into the charge: too weak a flame floats, too strong a flame scours the coating;
- The nozzle geometry: the diameters of the fuel nozzles and the air slots: the tip velocities: the cross-section of the annuli: the maintenance set point of the burner;
- The flame parameters: the flame length, the flame shape, the flame gas temperature: the result of the velocity and the mixing: the things the operator watches on the camera;
The five outputs of the file: from the fuel wagon to the flame camera: the calculation page is the single sheet where the burner team reads the whole burner: the document of the firing day, calculated in the morning and observed in the shift.
2. The Inputs of the Calculation: The Starting Data
Every calculation begins with the inputs, and the file organizes them in the three groups of the start:
- The production side: the clinker production in tons per day, the heat consumption of the kiln in kilocalories per kilogram of clinker (or the megajoule per ton), the fuel share of the main burner (typically 90-100% the total of the kiln fuel in the simple lines, less with the calciner);
- The fuel side: the net calorific value of the fuel in kilocalories per kilogram (or MJ/Nm3 for the gas): the density for the liquids, the composition for the calculation of the air demand: the fuel quality card of the plant;
- The air side: the total combustion air of the kiln: the primary air percentage (the burner air) and its split between the axial and the swirl: the oxygen of the kiln feed gas: the target O2 of the plant: the fans: the velocities at the kiln:
- The burner side: the physical dimensions of the burner: the tip areas of the nozzles, the annular gaps of the channels, the number of the holes: the installed:
The three groups of the inputs: the numbers the plant already knows: the file asks for them in the yellow cells and returns the red cells of the outputs: the clean formatting of the sheet, the discipline of the file: the engineering under the given inputs: the file also keeps the last ten calculation runs in the history rows, so the engineer compares the today numbers with the last change and sees the effect of the tip replacement or the fuel switch at a glance: the traceable calculation, the audit of the burner.
3. The Calculation of the Fuel Flow: The Heart of the Sheet
The first output of the burner file, the fuel flow, follows the classical thermal balance of the kiln:
- The heat demand: the production (t/h) multiplied by the specific heat consumption (kcal/kg, typically 750–850 kcal/kg for the modern five-stage preheater lines with the clinker at 3,000-4,000 kcal per kg): the clinker heat demand of the kiln in kcal/h;
- The fuel rate: the heat demand divided by the net calorific value of the fuel and adjusted by the thermal efficiency of the system (combustion efficiency at 98-99% and the heat losses): the ton per hour of the fuel: the file’s first answer: the fuel quota of the operator;
- The fuel split: in the precalciner kilns the burner fires a share (60-70% of the total often) and the calciner the rest: the burner calculation applies to the kiln burner share; the file tabulates the split and its effect on the flame and the burning zone load;
The example of the file: the kiln at 5,500 tons per day (229 tons per hour), the heat consumption 135 kcal per kg (3,200 kcal per clinker), the coal at 26 MJ/kg net: the heat demand 229 x 3,200,000 = 733 million kcal/h = 3,069,000 MJ/h; the fuel 3,069,000/26 = 118.000 kg/h = 118 t/h of coal: the operator reads the flow and the coal mill supplies it: the fuel flow of the day, the file’s first red cell.
4. The Combustion Air: The Number of the Primary
The heart of the burner design, the split of the combustion air, occupies its chapter in the file:
- The total air: the stoichiometric demand of the fuel (about 2.7 kg of air per kg of coal at 26 MJ with the excess) plus the excess air of the kiln (10-15% at the kiln: the O2 at the kiln inlet of 1.5-3%): the volumes of the kiln total air;
- The primary air: the burner air, normally 4-15% of the stoichiometric total for the standard solid fuel burners (a pinch to the old practice 25-40% with the high momentum of the early days): the modern: the axial and the swirl: the file tables the percentages per burner type;
- The secondary air: the hot cooling air enters the kiln around the flame through the hood: the secondary: the remaining: its quantity the calculation returns and its temperature defines it:
- The velocities: the primary jet velocities: the axial at 100-200 m/s for the high momentum burners, the swirl between 80-150 m/s: the recommended ranges of the suppliers: the milestones of the file: the momentum of the jet follows;
The primary/secondary split is the lever of the flame: the high primary momentum the short intense flame, the low momentum the long lazy flame: the file computes the momentum from these velocities and the flows: the two numbers that the burner supervisors adjust by the hour: the air, the momentum: the flame shape: the heated zone: where the refractory and the coating meet the numbers.
5. The Momentum and the Flame Shape: The Key Numbers
The momentum of the burner jet is the most decisive calculated value of the burner: the file calculates it as the product of the mass flow of the primary air and its velocity (times the cosine of the angle): the momentum numbers of the industry are quoted in newtons and the reference values of the modern burners range roughly between 4,000 and 12,000 N for the kilns of 3,000 to 7,000 tons per day, with the specific momentum of 25-60 N per ton of the clinker per hour as the practical yardstick of the design comparisons: the file tables both scales so the engineer of any kiln finds the reference that fits his numbers.
- Momentum: the standard of the flame shape: the longer jet carries the fuel deep: the momentum values of the modern burners of the cement kiln: 4,000-12,000 N (the ranges of the European examples): the file’s exponent: the momentum tax per the clinker tonnage;
- The flame length: the classic linked to the momentum: high momentum: the short, the fat flame: the low momentum: the long, the thin: the choice by the kiln geometry: the coating of the burning zone, the refractory lifetime:
- The flame gas: the stoichiometry at the flame: the mixture inside the flame is slower than the total: the variables: the 700,000 osculant the file the formula: the flame radiation follows the mixing:
The momentum calculation closes the physics of the design: the file’s result is the parameter C (the momentum per the flow) used by the burner makers: the plants with the kiln’s coating issues compare their momentum with the reference table: the file teaches: the flame is the tool: the momentum is the handle.
6. The Burner Geometry: The Nozzle and the Slots
The mechanical side of the burner, the geometry table of the file, defines the output of the actual nozzle:
- The nozzle area: the cross section of the axial nozzles and the swirl vanes: the flow through the area at the design velocity: the file back-calculates the required area from the flow and the velocity: the throat diameter of the tip:
- The annular gap: the gap between the burner pipe and the wall of its sleeve: the gap area: the swirl chamber: the design of the swirl:
- The angle effects: the swirl angle quotes of 15-60 degrees: the angle defines the axial/swirl split of the jet and the recirculation zone at the burner: the table of the angles versus the flame:
- The pipe: the fall velocities: the fluid of the fuel inside the pipe before the tip: the abrasion of the solid fuels: the wear: the replacement plan:
The geometry chapter is where the design engineers work: from the fuel and the flow the file derives the areas, from the areas the supplier cuts the tip: the kiln has one chance: the wrong geometry: the flame asymmetry: the hot spots: the file verifies the geometry of the burner per the flow: the same set of numbers the mechanical shop and the firing team share.
7. The Flames: The Combustion Model of the File
The file goes beyond the mechanical construction: it estimates the flame by the combustion data:
- The primary air ratio: the volumetric mix of the primary: the flame: the 5% of the primary air of the moderns: the fiber-lid hybrid flame: the residence time:
- The flame length: the facility correlations (the momentum and the primary rate) give the flame length in the multiples of the kiln diameter (3-6 diameters typical): the table: the burning zone length: the coating:
- The heat release and its: the temperature of the flame (conventional: ken 1,100 to 1,300 deg C of the flame ends): the heat of the flame: the concentrated: the flash of the burning zone — the air:
- The quick of the design: the permissible heat release per the burner: the mW/m3 limit: the file restrains the flame from the burning ’s stones (the vertical): the boiler balance furnace:
The combustion chapter takes the calculated numbers to the qualitative zone: the engineers of the kiln look for the flame photos and the coating maps: the file overlays the charts on the tables: the quantitative support of the visual judgment: the flame: the calculated, then the observed: both of the file.
8. The Example: One Complete Burner Calculation
Follow the file through the complete example, the one the reference sheets document:
Given: the kiln 3,500 t/d clinker (146 t/h), the heat consumption 330 kcal/kg, the coal 24 MJ/kg (5,750 kcal/kg): the primary air 8% of the total, the oxygen set 2% at the kiln: the burner mass: the two-channel: the axial 40% of the primary going the axial at 180 m/s, the swirl 60% at 110 m/s:
The flow: the fuel: 146,000 kg/h × 3,300 kcal/kg / 5,750 kcal/kg = 83,800 kg/h (83.8 t/h) of coal: the total stoich air: the coal with the 12.0 Nm3/kg (the typical) = 1,065,000 Nm3/h: the primary: 10% = 106,500 Nm3/h: the momentum: the 106,500 Nm3/h × the density 1.19 kg/Nm3 = 126,700 kg/h × the 160 m/s averaged = 20,200 N: the momentum per ton of the clinker: 20,200/146 = 138 N/t h: the file rates it against the recommendation table: within, the flame the designed: the result of the file: the same sheet the operator holds the shifts: the complete, the calculated.
9. The Common Failures and the Diagnostics: The Files’ Practice
The calculation file also carries the diagnosis of the most studied burner faults of the industry:
- The low momentum: the flame weak: fuel drops in the nose, the coating forms irregularly: check the velocities: the primary air flow: the nozzle abrasion: the file numbers show the deficiency before the coating does;
- The high momentum: the flame scatters: the burning in the nose: the tip temperature rising: the prevention: reduce the axial, widen the gap: the file’s red cells flag the borderline values;
- Flame asymmetry: the wear of the swirl channels, the deposits: the flame tilt, the hot spot, the refractory: the file computes the per channel numbers and the comparisons of the sides reveal: the asymmetry:
- The fuel problems: the moisture of the coal, the low calorific value: the file shows the flow computed from the actual heating value: the operator’s wrong feed: the variable of the flow: the diagnostics:
The common-failure chapter makes the spreadsheet a maintenance tool: the diagnosis of the numbers precedes the diagnosis of the flame: the kiln team of the modern plants calculates before the camera: the preventive of the burner: the file: the toolbox of the fire: the same failure logic serves the commissioning of the new burner: the first weeks of the firing compare the calculated momentum with the measured tip temperatures and the coating build, and the deviations drive the fine-tuning of the axial and the swirl shares: the calculation file is the commissioning protocol of the burner as much as its design sheet.
10. The Burner Calculations in the New and the Existing Plants
The applications of the file divide into the two worlds of the cement engineer:
- The new kilns: the design: the burner spec per the desired flame & momentum: the file runs the preliminary numbers: the project engineer checks the supplier and the burner and gets the validation: the same outputs of the performance test after the start-up;
- The existing kilns: the fuel switch to the alternative fuels, the waste-derived, the lower calorific: the burner ratings of the tonnage recheck and re-select: the file’s multi-fuel rows: the coal, the petcoke, the AFR: each with the own NCV and the own primary needs: the conversion planning;
- The burner modification: the tip exchange, the mode of the channels, the addition of the central pipe: the file on the desiring and the result: the before-after simulation: the safety of the step;
The two flows (the new and the retrofit) share the one sheet: the file adapts by the inputs: the kiln, the fuel and the desired flame: the calculations of the burner belong to every stage of the plant’s life: the torch of the firing, computed all the years: the budget line of the engineering: the expertise in the spreadsheet: and the file keeps the history of the calculation versions so the audits and the modifications of the future read the reasoning of the past: the versioned engineering of the burner.
11. The Burner of the Precalciner Kilns: The Two Flames
The modern precalciner lines fire at two points, and the file documents the burner calculations of both in the same workbook:
- The kiln burner: the main flame in the nose of the kiln: here the calculations described in the previous chapters apply: the primary air, the momentum and the flame for the burning zone: the pyrotechnics of the sinter;
- The calciner burner: the flame and the hot gases of the calciner vessel: the calcination of the meal to 90-95% before the kiln: the burner calculations differ: the lower temperature target (850-900°C), the mixing by the tertiary air, the particle suspension: the calciner air calculations (the kiln air 40-60%, the tertiary air 40-60% of the total) belong to the file’s second sheet;
- The load split: the 40-60% of the heat in the preheater system and the rest at the kiln: the firing rates: the file lets the engineer allocate the fuel shares by the clinker production before the calciner loop: the balance sheet of the two flames;
- The alternative in the calciner: the calciner accepts the cheaper alternative fuels (the tires, the sludge, the RDF) more tolerantly than the main flame because in the flash environment the combustion is less sensitivity to the momentum: the file tabulates the calciner-friendly fuel shares: the economy of the line, designed.
The two-flame chapter describes the modern reality: the kiln burner is the partner of the calciner, and the calculations of the two pairs form the full firing design of the production line: the file’s workbook covers the pair, and the engineer of the new line calculates both flames on the same sheet before the concrete is poured: the firing system complete: the two torches, the one file.
12. The Alternative Fuel Burners: The Calculations of the Substitution
The alternative fuel (AF) rate of the cement industry grows yearly, and the burner calculation extends to the substitution scenarios:
- The fuel characteristics: the shredded tires (25-31 MJ/kg), the RDF/SRF (15-20 MJ/kg), the waste oils, the solvents, the meat and bone meal, the plastic flakes: each carries its own calorific value, volatile content and ash: the file carries the row for each and the mixture: the NCV of the blend is the weighted mean of the fractions;
- The firing limits: the maximum stable AFR through the main burner depends on the volatiles, the moisture and the particle size: too large the coarse particles do not burn fully in the flame and nest in the charge: the file’s limits rows for the main burner: the substitution of the 30-80% in the kilns of the world;
- The re-calculation: each rate change re-calculates the primary air and the momentum of the blend: the new volatiles demand the new axial: the switch of the day: the file’s instant: the team:
- The emissions watch: the alternative fuel changes the CO, NOx and the chloride cycles: the burner calc feeds the process control: the file columns the emissions flags: the compliance of the substitution: the planned, the measured.
The alternative chapter is the future of the file: the substitution is no longer the experiment but the standard: the burner calculation of the package runs the blends of the modern fuel market: the engineer of the alternative plant enters the actual NCV, reads the flow, keeps the flame: the spreadsheet and the future, together: the cement industry of the burning, computed.
13. The Frequently Asked Questions:
Why is the primary air split into the axial and the swirl?
The split is the mechanism of the flame sculpture: the axial jet carries the fuel forward and gives the flame its length and its penetration, the swirl jet rotates the outer layers of the flame, recirculates the hot gases to the root of the flame and stabilizes the ignition at the tip: the ratio of the two equals the shape: more axial, the longer and the narrower flame; more swirl, the shorter and the broader flame with the better mixing: the file provides the recommended ranges of the split (the axial 30-70% of the primary) and the operator uses the ratio as the daily tuning wheel of the flame: the momentum and the ratio, the two handles of the burning zone.
What is the optimum primary air percentage for the modern burner?
The recent designs of the high momentum operate in the 4-10% band of the total combustion air (much lower than the old 25% of the older burners): the low primary gains the secondary air and the kiln ventilation: the file’s tables for the type: the values of each design in the selections: the exact of the particular: the drum.
How often should the burner calculations be redone?
The calculations accompany every change: the new fuel, the new burner tip, the major repair of the burner, the start-up after the conversion: beyond these, the periodic monthly check of the primary air flow and the momentum from the DCS values keeps the flame within the design envelope: the file’s trend sheet records the monthly momentum, and the drift beyond five percent triggers the inspection: the burner of the plant: calculated at the change, verified every month: the discipline of the numbers.
The calculations accompany every change: the new fuel, the new burner tip, the major repair of the bag, the start-up of the conversion: the maintenance between them: the periodic monthly check of the primary air flow and the momentum from the DCS: the plant with the file: the continuous: the file’s redid: the discipline.
Can the same burner fire the coal and the alternative fuels?
Yes, the modern multi-channel burners are built for the flexibility: the fuel switch requires the re-calculation of the primary split and the velocity: the file has the multi-fuel: the same formula with the new calorific value and the volatile content: the switch planning: the validation: the alternative’s risk of the higher moisture: the file covers: the one burner, the many fuels, the one complete calc sheet.
Is the momentum value measured at the plant?
In the modern plants about 50% of running the DCS conductors: the momentum is calculated from the measured flows and the velocities: the lab scale of the kiln: the file has the input fields: the operator enters the measurements: the momentum the red cell: the trend of the momentum is the early flag of the nozzle wear: the numbers of the file replace the guess-with-the-stopped operations: the monitoring, the maintenance, the calculation.
The momentum is low although the primary air is high: what can it be?
Check the velocity first: the high flow with the low velocity means the area is too large: the nozzle worn or the wrong tip replaced: the file derives the velocity from the flow and the area, and the red comparison with the design exposes the degraded tip: then the swirl angle: the deposits in the swirl channels reduce the tangential component and the effective momentum: the file compares the swirl contribution to the total: the maintenance action: the tip or the channels: the calculation points the part.
Does the file include a filled example and the Excel?
Yes: the package’s burner workbook ships with the completed calculation sheet and the empty matrices: the two in one: the engineer copies the example, replaces the inputs, and the sheet results a validated-format number; the same workbook and the other calculation templates of the package: the envelope: the whole 931; again the multi-topic library of the engineer’s: all in the Complete package.
14. Conclusion
The burner calculation file brings the flame of the kiln into the spreadsheet: the fuel, the air, the momentum, the geometry: each with its number: the kiln engineer calculates the burner at the design table as at the shift table: the same sheet: the flame is perhaps the most technical object of the cement plant: and the file makes it the most calculable.
The burner: the 80% of the process: the calculated: the burning zone: the heat: the coating: the lifespan: the file and the full burner suite: the Complete Cement Technical Package: the 931 files: the one-time 249.99: the PayPal: the instant: the library: this article: the reader: the calculation of the burner: the spreadsheet of the flame: the package of the cement, delivered: the confidence of the computed flame: the knowledge of the burning: the purchase below opens the workbook and the whole library of the engineer: the complete collection and the authority of the numbers: yours.
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