Main Fans in Cement plant

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To download the below  and all other Useful Books and calculations Excel sheets please click here 

To download the below  and all other Useful Books and calculations Excel sheets please click here 


Main Fans in Cement plant

by Daniel Brassel / Jan C. Kaminsky (CTS – TPT)

Things that I want to talk about…

  • Design and Efficiency of Impellers
  • Fan Equations and Performance Curves
  • Flow Control
  • Operational problems

Learning Objectives

  • Know principal impeller designs
  • Understand basics of fan equations and  fan curves
  • Know different types of flow control
  • Understand what influence the  reliability

Enormous power consumption by main fans

Altogether these fans consume between 30% and 50%  of the plant’s total electrical energy.

  • Kiln ID Fan
  • Raw Mill Fan
  • Cooler Exhaust Gas Fan
  • Kiln Dedusting Fan

The lower the dust load the better the fan can be

 power consumption Equation for Main Fans

Saving money with high efficiency fans

Fan performance curves to be proven in plant

derived from  laboratory data

conditions at  fan inlet


-Fan static pressure

– Fan power

-System resistance curve

Operating point  where curves meet

For Plant Performance

Volume Flow

Static Pressure

Power Requirement

Lower pressure achieved at higher temperature

The static pressure generated by the fan is depending on the gas density, i.e.  type of gas  and  temperature.

Influence of density change


Bad and good flow control

Cooler Undergrate Fan: Radial Inlet Van

Preferred: the variable speed drive (VSD)

Flow Regulation by Outlet Damper

Flow Regulation by Inlet Vane Damper

Flow Regulation by Inlet Box Damper

Flow Regulation by Speed Control

fight the false air

Fan capacity low

System changes:

eliminate false air

reduce pressure drop

Fan changes

increase fan speed

increase wheel diameter

replace rotor

Fans Vibration Invisible because inside

Example of Build-ups

Reason of Sticky dust on Fans Blade

  • Mineralogical Composition of Raw Mix
  • Burning Conditions
  • Duct / Fan Arrangement
  • High Temperatures
  • Inappropriate Blade Shape and Angles
  • High Fan Speed
  • Dew Point Problems

Fight the build-ups with modifications

Permanent remedy could be gained through:

  • Change of duct / fan arrangement
  • Change of fan speed or impeller diameter
  • Modification of fan inlet or impeller blade shape
  • Larger shaft diameter (stronger design)
  • Anti-sticking painting

If the above listed measures do not solve the problem, regular cleaning has to be envisaged


Cleaning the fan on-line

  • High pressure water spray
  • Steam injection
  • Compressed air injection
  • Sand blasting
  • Acoustic Resonance (ultrasonic)
  • Dynamic balancing

Acoustic Cleaning Devices

Sand Cleaning Device

Cracking the dust layer

Erosion / Wear of Cement plant Fans

Blade erosion:

varies in the second or third power of the speed of a particle that hits the blade

particle speed is proportional to the rotor speed

is affected by the wheel inlet velocity?

 fan flow divided by smallest inlet section

Cement plant Fans Wear Protection

Direct protection

=Increased thickness of wear parts

= Direct hard surfacing

=Glued-on ceramics (but: for example max. 130 °C)


Protection by wear plates

-Corners or mild steel plates

-Abrasion resistant steel plates

-Mild steel plates with hard surfacing

Deflector plates

Wear Protection by Particle Deflection

Example of Deflector Plates

Which fan is right?

Continuous  operation




Fan efficiency

mechanical design

type of regulation

for more information please

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