Fan Engineering: Complete Technical Guide
Fan engineering: the discipline of the gas movement in the cement plant: the raw mill fan, the kiln ID fan, the cooler fans, the filter fans, the separator fan, the false air wars: the gas flows through every process and the fans move it: the pressure, the flow, the curves, the laws, the selection, the drives, the vibration and the maintenance: the fan is often the largest single motor of the plant: the knowledge of the fans pays in the kWh and the uptime: this file is the complete fan engineering manual of the cement plant.
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 fan engineering chapter with the fan laws, the curve workbooks, the selection sheets, the vibration limits and the troubleshooting tables: the package is the library of the process equipment: this article presents the fan file in its own order.
This article follows the fan file: the theory, the types, the curves, the selection, the drives, the installation, the operation, the vibration, the maintenance and the examples: the reader with the file in hand can dimension his next fan and diagnose his current problem.
1. The Role of the Fans in the Cement Plant
The fans of the plant, one by one, and each has its duty:
- The kiln induced draft (ID) fan: the big fan at the end of the preheater: moves the gas of the kiln and the preheater: the 300,000-800,000 m3/h, the pressure 400-800 mbar: the speed control: the most powerful fan of the plant:
- The raw mill fan: the gas through the raw mill: the drying gas and the product separation: the 200-400 mbar: the VFD: the ventilation of the mill:
- The cooler fans: the under-grate fans of the clinker cooler: the high pressure and the high volume: the cooling air 1.5-2.5 Nm3 per kg of the clinker: the grate cooling:
- The filter fans and the bag-house: the dedusting of the transfer points, the mills, the silos: the flow per the filter: the suction:
- The separator fans: the circulating air of the dynamic separators: the fines transport: the classification:
- The boosters and the false air: the false air in-leakage is the enemy: the sealing of the system: every droplet of the false air makes the fan bigger and the energy higher: the file: the false air measurement (the O2 profile) and the sealing program:
THE FAN MAP of the plant: the engineer draws the process with the fans on the drawing: the flow of the gas from the kiln to the stack: the fans are the pumps of the gas system: the pressure and the flow at each station: the file: the map of the typical dry process plant: the pressure profile: the fan duty of every line: the starting point of the fan engineering.
2. The Fan Theory: The Flow, the Pressure and the Power
The physics of the fan in the practical numbers:
- The flow (V): the volume flow of the gas: the m3/h or m3/s: the gas at the operating conditions (the temperature: the kiln gas at 200-350°C after the preheater): the fan flow at the operating density:
- The pressure: the static pressure, the velocity pressure and the total pressure: the fan delivers the total pressure: the system needs the static: the fan curve, the system curve: the operation point at the intersection:
- The power: P (kW) = V × Δ p / η (with the units of the file): the efficiency of the fan 70-85%: the fan and the motor: the drive losses: the file: the power formula in the practical units:
- The density corrections: the fans are rated at the density of the air at 20°C: the hot gases (the density lower) change the flow and the power: the correction factor of the temperature and the altitude: the file: the density correction table: the critical number of the kiln fan selection:
THE UNITS of the fan engineering: the Pa, the mbar, the mmWG: the conversions of the file: the Nm3 (the normal conditions: 0°C, 1.013 bar, dry) vs the Am3 (the actual conditions): the fan works in the actual conditions: the capacities of the vendors in the catalog: the engineering converts: the file: the conversion sheet: the beginner’s chapter: the discipline of the units is the discipline of the fan: the same fan at the different conditions: the different capacity: the selection without the correction: the common error of the industry.
3. The Fan Types: The Centrifugal and the Axial
The fans of the plant come in the two families with the variations:
- The radial (the centrifugal) fans: the gas enters the axis and leaves the periphery: the high pressure: the robustness: the families by the blade: the radial (the dust, the wear: the thick dust), the forward-curved (the high volume, the low pressure, the compact), the backward-inclined (the highest efficiency: the modern standard), the airfoil (the best efficiency, the clean gas):
- The double inlet: the gas enters from the two sides: the large flows: the preheater fans: the balancing of the inlets: the bearing arrangement:
- The axial fans: the gas flows along the axis: the high flow and the low pressure: the cooler roof fans, the cooling towers, the ventilation: the adjustable pitch blades: the axial of the cement plant: the roof:
- The process selection: the dust load (the radial: the cleaning of the impeller), the pressure (the radial), the efficiency (the backward), the flow (the double inlet): the file: the selection matrix of the fan types: the typical application table: the fan of the kiln: the double inlet, backward: the filter fan: the radial:
THE BLADE FAMILIES: the file: the efficiency curves of the families: the peak of the backward-inclined ~85%, the radial ~75%, the forward ~70%: the plant that selects the backward at the peak saves the kWh for the decades: the fan is the machine with the greatest energy saving potential of the cement plant: the file: the family selection: the operating point: the design point: the efficiency at the point, not the peak: the file table.
4. The Fan Curves: The Map of the Machine
The fan curve is the identity of the machine: the pressure vs the flow:
- The characteristic curve: for every speed, the fan gives the pressure vs the flow curve: the P-V curve: the higher the flow, the lower the pressure (the backward curve dips): the curve-to-curve family at the different speeds:
- The system curve: the pressure drop of the plant vs the flow: the quadratic curve (the P ∝ V² for the fixed system): the intersection of the fan and the system curves: the operating point: the flow and the pressure of the actual:
- The surge region: the region of the instability at the low flows (the aerofoil fans): the surging: the flow reversal: the damage: the operation must stay the right of the surge line: the file: the surge margin:
- The parallel and the series: the fans in parallel (the flow add: the two fans of the kiln): the fans in series (the pressure add: the boosters): the stability of the parallel operation: the file: the parallel curves: the two fans:
THE OPERATING POINT in the plant: the actual flow: the draft at the kiln inlet (-300 mbar), the ID fan point: the file: the drawing of the system curve: the measurement of the actual: the fan at the design point and the fan in the reality: the differences: the false air: the fan test of the plant: the file: the field measurement: the pressure, the flow, the speed: the plot: the diagnosis of the plant changes: the fan curve: the mirror of the process: the engineer reads the fan and knows the system.
5. The Control of the Fans: The Volume and the Energy
The plant must control the volume of the gas: the ways of the fan control and their economics:
- The damper control: the throttle in the duct: the friction of the damper: the flow at the fan pressure: the simple, the cheap, the waste: the damper control of the kiln: the old plants:
- The inlet vane control: the guide vanes at the fan inlet: the pre-swirl: the changing pressure curve: the improvement over the damper: the moderate: the classic: the inlet vanes of the kiln ID fan:
- The speed control (the VFD): the frequency drive changes the speed: the fan laws: the flow ∝ speed, pressure ∝ speed², power ∝ speed³: the cubic relationship: the energy saving of the VFD: 70% flow: the power at 34%: the fan laws: the modern control of the big fans: the VFD of the kiln ID fan: the standard of the new plants:
- The hydraulic couplings and the pole-changing: the older speed controls: the hydro-coupling losses: the two-speed motors: the historical:
- The law application: the parallel operation: the sharing: the control of the two fans: the file: the control matrix: the damper, the vanes, the VFD: the economics: the payback: the file: the fan energy audit: the kWh of the fans per ton of the clinker: the target: the improvement:
THE ENERGY OF THE FANS: the fans consume the 20-25% of the plant’s power: the control method decides the half: the VFD of the kiln fan: the classic payback project of the cement industry: the file: the audit: the calculation of the saving: the case: the 400 kW kiln fan at the 70% of the load: the damper vs the VFD: the 150 kW saved: the 6000 hours: the electricity price: the payback in the months: the energy: the engineering: the file.
6. The Fan Selection: The Step-by-Step of the File
The complete selection procedure of a process fan:
- Step 1: the duty: the gas flow (the actual conditions), the gas temperature, the composition, the dust content, the pressure requirement, the altitude: the data of the process:
- Step 2: the density: the gas density at the operating conditions: the correction of the temperature and the altitude: the selection basis: the file: the density calculator:
- Step 3: the type: the dust (the radial: the wear), the pressure (the radial), the efficiency (the backward), the capacity (the double inlet): the selection of the family: the file: the matrix:
- Step 4: the catalog: the vendor: the fan at the design point: the curve: the efficiency: the typical: the total: the pressure margin 10%: the flow margin: the file: the data sheet: the comparison of the vendors:
- Step 5: the motor: the fan speed, the drive: the motor power: the 10-15% margin: the starting torque, the inertia: the VFD: the motor: the file: the motor selection table: the power factor:
- Step 6: the auxiliaries: the bearings, the lubrication, the vibration sensors, the discharge silencer, the expansion joints: the complete fan system: the file: the checklist:
THE WORKED EXAMPLE of the file: the kiln fan: the 320,000 m3/h (actual) at 200°C, the pressure 450 mbar, the dust 20 mg: the density corrected: the selection: the double inlet, the backward-inclined: the 6.5 m impeller: the 220 rpm: the motor 2,800 kW: the VFD: the contract: the numbers from the beginning to the end: the designer’s skill: the examples of the file: the selection: the tender: the check of the vendor’s curve: the file gives the complete method.
7. The Installation and the Operating Conditions
The fan is installed in the plant, not on the paper: the practice:
- The inlet and the outlet ducts: the straight runs, the vanes and the turns: the pressure losses: the velocity 15-25 m/s: the flow distribution at the inlet: the diffuser: the file: the duct design: the losses of the elbows: the balancing:
- However: the isolation and the expansion: the flexible connections: the thermal expansion of the duct: the vibration isolation: the support: the anchoring that does not fight the expansion:
- The silencers: the fan noise: the 100-110 dB at the kiln fan: the silencer selection: the noise limits: the protection of the personnel: the file: the noise chapter: the acoustic barriers:
- The erosion and the abrasion: the dust at the high velocity: the wear of the blades and the casing: the protection liners, the hard coatings, the velocity limits, the dust separation upstream: the file: the wear design:
- The access: The fitters made the bearing accessible, the inspection doors, the lifting: the maintenance needs: the installation: the file: the layout rules:
THE INSTALLATION chapters: the fan system is not the fan alone: the duct, the connections, the drives, the civil: the engineer of the file: the drawing: the complete package: the fan contract: the delivery, the field, the commissioning: the checklist of the file: the measurement of the flow at the commissioning: the acceptance: the file: the commissioning procedure: the run-hour goals: the fan: the test: the vibration, the temperature, the flow: the handover.
8. The Vibration: The Language of the Fan Health
The vibration of the fans: the most reliable health signal:
- The sources: the unbalance (the dust build-up, the erosion, the corrosion), the misalignment (the coupling, the belt), the bearing defect, the blade resonance: the resonance of the blades and the casing: the duct:
- The measurement: the overall vibration (the mm/s RMS) at the bearing housings: the trend: the limits: the standard families (the ISO 10816): the zones A-D: the alarm: the trip: the file: the limit tables:
- The spectrum analysis: the 1st harmonic (the unbalance), the 2nd (the misalignment), the harmonics of the blade passing frequency (the blade passage: the aerodynamic: the blade, the casing: the file: the vibration patterns: the signal, the meaning:
- The balancing: the dynamic balancing in situ: the two-plane: the used procedure: the file: the balancing procedure: the acceptable residual: the field: the plant does the balance: the maintenance:
THE VIBRATION MONITORING: the sensors on the fan bearings, the online system of the big fans: the trends: the changes: the planning of the shutdown: the file: the vibration management: the “baseline and the trend” philosophy: the fan: the 3-year run: the monitoring maintains: the file: the example of the kiln fan: the sand build-up: the vibration at the 5 mm/s: the cleaning the blade: the 1.5: the file: the case: the vibration: the language: the engineer of the file: the speaker: the balance: the file.
9. The Maintenance of the Fans: The Care of the Machine
The maintenance plan of the fans in the plant:
- The daily: the patrol: the noise, the temperature, the vibration, the smoke of the bearing: the lubrication level: the drain: the records:
- The lubrication schedule: the bearings, the greases, the intervals: the oil: the analysis: the reload: the file: the lubrication table of the fan:
- The inspection: the quarterly: the blades, the casing, the inlet cone, the wear (the check: the pit the erosion), the fasteners: the file: the inspection report forms:
- The overhaul: the yearly: the impeller NDT (the crack detection), the balance check, the bearing replacement, the stator: the balancing: the file: the overhaul procedure:
- The spare parts: the critical spares of the fan: the bearings, the lip seals, the gaskets, the spare rotating assembly: the storage: the file: the list of the recommended spares:
THE MAINTENANCE PLAN: the CBM (the condition-based) with the vibration: the planned shutdowns: the fan: the critical machine: the failure of the kiln fan: the stops of the whole kiln: the file: the maintenance planning of the fans: the criticality ranking: the spare strategy: the plant: the fan availability: the clinker cost: the file: the maintenance: the complete: the fan care: the “the fan is simple but the neglect is expensive” the file.
10. The Troubleshooting of the Fans: The Diagnostic Tables
The problems of the fans and the answers of the file:
- The low flow: the blade worn, the speed low, the damper closed, the blockage, the false air, the density wrong: the checks: the flow, the pressure, the speed, the actual:
- The low pressure: the worn impeller, the incorrect speed, the blade angle (the axial), the leak: the test: the pressure: the file:
- The high vibration: as the previous: the classify: the unbalance (1x), the misalignment (2x), the bearing (the high-frequency), the resonance: the spectra: the remedies: the file: the decision tree:
- The high temperature: the bearing, the lube failure, the cooling failure: the checks: the alarms:
- The noise: the surge, the cavitation (the blowers), the loose parts: the file: the diagnosis:
- The motor overload: the flow high (the system change), the density high, the speed high, the belt tight: the check of the point: the motor: the file:
THE TROUBLESHOOTING TREES of the file: the symptom t the cause: the check: the fix: the one-page matrices: the engineer of the plant: the field: the diagnostic: the quick: the file: the examples: the fan: the vibration: the debris: the “the flutter”: the classic: the file: the section: the “the diagnostician” the skill: the fan: the language: the plant: the file: the practice.
11. The Energy Audit of the Fans: The kWh of the Plant
The fans of the plant: the power: the audit:
- The specific consumption: the kWh per ton of the clinker of the fan power: the typical 25-35 kWh/t of the clinker (with the mill fans: 15-20): the benchmark of the file: the comparison of the plants:
- The audit procedure: the measurement of the flow, the pressure and the power of each fan: the efficiency: the comparison with the curve: the identification of the bad performers: the plan:
- The saving measures: the VFD control, the false air reduction, the duct sealing, the impeller efficiency (the backward), the aftercooling, the use of the waste heat: the list: the quantified: the file: the measure: the implementation: the verification:
- The report: the audit report: the plan of the cents AB: the ranking of the actions: the file: the energy: the fan: the big: the measured: the file: the kWh: the audit: the plan:
THE FAN ENERGY: the plant’s “the fans” the reports: the specific: the 30: the actual: the best: the 20: the difference: the potential: the file: the audit: the implementation: the “low hanging”: the VFD: the false air: the duct: the file: the kWh: the audit: the carbon (the fans: the electricity: the emissions): the file: the energy: the wire: the kW: the end: the audit: the complete: the file.
12. The Fan Testing: The Measurement and the Verification
The fan is only as good as its proof: the performance test chapter of the file:
- The flow measurement: the traverse of the ductwith the pitot tube or the anemometer: the grid points: the velocity profile: the mean velocity times the area: the flow: the ISO and the AMCA standards: the file: the traverse worksheet:
- The pressure measurement: the static pressure at the fan inlet and outlet: the correction of the duct losses: the fan pressure: the point on the curve: the verification of the operation: the file: the pressure diagram:
- The power measurement: the electrical input of the motor: the efficiency chain: the motor, the belt/drive, the fan: the fan power: the fan efficiency: the comparison with the catalog: the performance curves: the field test: the file: the test records:
- The acceptance test: the contract testing of the new fans: the works test and the site test: the tolerances of the ISO 5801: the vendor’s curves vs the site: the acceptance procedure of the file: the claim and the review:
- The periodic audits: the annual: the efficiency change, the wear: the re-test after the impeller change: the trending: the energy of the fan: the audit: the file: the audit sheets of the plant:
THE TEST: the numbers “the truth”: the fan test is not the laboratory activity: it is the quarterly discipline of the plant: the test reveals the worn blades, the deposits under-pressure, the wrong speed and the wrong control: the file takes the engineer through the whole test: the pitot traverse, the pressure taps, the kW meter, the calculation sheet: the test numbers feed the audit and the savings: the file: the complete testing chapter: the fan: the verification: the numbers of the plant: the engineering: the fans: the professional: the file: never the blind faith: measure: the cement: the plant: the efficiency: the kWh: the complete.
13. The Fan Applications of the Cement Plant: The Case Sheets
The fans of the plant, one case per machine, in the application chapter of the file:
- The kiln ID fan: the largest single fan: the draft across the whole preheater and the kiln: the 250–400 mbar, the 300,000–500,000 m³/h: the temperature 150–350°C at the inlet: the energy 2–4 kWh/t: the case sheet: the parameters, the wear, the control;
- The raw mill fan: the mill ventilation and the drying gas: the flow after the filter: the pressure of the mill system: the false air effect of the mill seals: the case: the raw mill fan audit;
- The cement mill vent fan: the small but the critical: the mill vent air, the filter: the temperature and the moisture of the vent: the clogging: the case:
- The separator fans: the closed circuit: the dynamic separators: the flow and the pressure: the classification: the case: the separator fan and its efficiency:
- The cooler fans: the grate zone fans: the air rates by zone: the heat transfer to the clinker: the fan power 15–25 kWh/t of the clinker including the cooling: the case: the cooler fans configuration:
- The aeration and the airslide blowers: the small roots blowers: the air slides, the silos: the fiel: the case: the air consumption of the homogenization:
THE CASE SHEETS: the file is not only the theory: the application pages show the real fans with the real numbers: the plant engineer recognizes his own machines: the typical failure, the typical fix: the file: the case: the fans: the wiring: the application: the engineering: the notebook: the reference: the complete: the fan: the cement: the industrial: the professional: the file: the fans: the “the case” the application: the practical: the full: the file: the fans of the plant: the complete: the case: the fan.
14. Frequently Asked Questions on the Fan Engineering
What is the difference between the static and the total pressure?
The static pressure is the pressure that the process resists: the velocity pressure is the dynamic component of the flow: the total is the sum: in the process selection, the static pressure is the same as the system requirement: the velocity pressure mostly wasted (except the recovery): the file: the units: the selection: the pressure: the practical: the fans of the static ratings: the file.
The kiln fan of the unknown capacity: how do I select?
Measure the flow, the pressure, the speed and the density: the file: the fan law versa: the actual point to the design: the impeller: the standard: the vendor: the fan: the performance test (the flow: the traverse: the static: the speed): the file: the “field testing” chapter: the numbers: the selection: the engineer: the data: the file: the fan: the selection: the unknown.
Why the VFD on the kiln fan?
The VFD adjusts the speed: the process needs the variable flow: the cubic relation of the power: the energy: 70% flow: 34% power: the damper control: the waste: the savings: the 1500 kW fan: the true: the VFD: the payback: the years of the electricity: the VFD also the smooth start: the file: the economics: the kiln fan: the savings: the kWh: the file.
My fan vibrates but the balance is good: what now?
The unbalance is the common but not the only: the misalignment, the bearing, the resonance, the aerodynamics (the blade stall, the surge): the spectrum: the 1x: the balance: the 2x: the alignment: the BPF: the aerodynamics: the resonance: the vibration: the file: the spectral table: the diagnosis: the measurement: the vibrations: the file: the vibration expert: the table.
Can the fan work with the high dust load?
Yes: the radial centrifugal with the robust blade (the straight: the backup plate), the lower speeds, the wear protection: the impeller: the cleaning: the buildup: the erosion: the file: the dust fans: the wear chapters: the impeller life: the file: the table: the hermitage: the maintenance: the dust: the RPM: the file: the answer: with the design and the care.
15. Conclusion: The Wind of the Plant
The fan engineering: the discipline of the air and the gas of the cement plant: the theory, the types, the curves, the control, the selection, the trouble and the maintenance: the fans: the lung: the plant breathes: the power: the 30% of the clinker: the engineering: the kWh: the uptime: the file: the fan manual: the complete: the engineer: the fan: the process: the result: the file: the career: the knowledge: the cement: the library: the package: the complete.
The Complete Cement Technical Package (931 files: $249.99 one-time: the PayPal: the instant download) includes the fan engineering chapter with the laws, curves, the selection workbook: the whole library: the kiln, the mill, the conveyor: the one price: the professional: the engineer: the fan: the wind: the plant: the knowledge: the package: the button: the PayPal: the download: the library: the cement: the complete: the engineering: the file: the wind of the plant: the library of the cement: the professional:
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