1. The Optimum Kiln System
1) 5 stage preheater with low pressure drop cyclones
5) Oversized kiln for AFR
2) Large in-line calciner with AFR feeder
6) High momentum multi channel burner
3) Low NOx with staged TA swirl chamber
7) High efficiency cooler
8) Roller crusher
4) Hot spot (e.g. chamber) staged meal feed
10) Splined tyre fixation
9) Pneumatic seals at both ends

2. Pre-Calciner: Typical Problems
1) CO at outlet of PC or cyclone
5) Material build-ups
6) Refractory damage
2) Locally too high temp.
7) Tertiary air damper failure
3) Unburnt fuel particles in hot meal
8) Tertiary air duct blockage (elbow type only)
4) Too high / low calcination degree

3. Main Benefits of Precalciner Technology
1. More stable kiln operation due to better kiln control via two separate fuel feed/control points
2. More stable kiln operation due to controlled meal conditions at kiln inlet
3. Reduced thermal load of burning zone
4. Lower refractory consumption as a result of 1. to 3.
5. More than double capacities possible with given kiln (10'000 t/d: 6 x 95m)
6. Possibility of increasing capacity of existing kilns
7. Reduced volatilisation of circulating elements
8. Reduction of cycles (S, Cl, Na2O, K2O) with lower bypass rate / losses
9. Makes short kilns possible with 2 stations, L/D < 12
10. Possibilities of NOx reduction
11. Lump fuel (AFR) utilization (in-line only)

4. True and Apparent Calcination Degree
True calcination degree: Degree to which the calcination is completed, i.e. extent to which the CO2 is dissociated from the CaCO3. Extremes: Raw meal 0% (LOI=35%) Clinker 100% (LOI= 0%)
Apparent calcination degree: The calcination degree determined from a hot meal sample taken from the meal duct of the bottom cyclone

5. Dimensioning Criteria for Precalciners
1. Gas Retention Time
(for combustion in pure air)
decisive for complete combustion
Fuel Reactivity
Gas Retention Time
low
> 3.5
sec
medium
> 2.5
high
> 2.0
2. Meal Retention Time
decisive for complete calcination
Actual meal retention times are 6 to 12 seconds,
at the above gas retention times.
Calcination takes much less than that which
means that meal retention time is not a
decisive design criteria.
Fuel Reactivity Examples:
Low:
Petrol coke
Medium:
Bituminous coal, natural gas
High:
Lignite, fuel oil
Inline Calciners:
Due to less favourable conditions for combustion
(presence of kiln gas, imperfect mixing of
tertiary air with kiln gas), the following rule of
thumb can be used for sizing this PC type:
Recommended gas retention time to 1 sec

6. Cyclone Preheater: Typical Problems
1) Dip tube missing or damaged
5) Too high velocity
6) Meal flaps not working
2) False air
7) Thermocouple bad location
3) Meal deposit
8) Splash plate worn; splash box not clean
4) Cyclone blockage

7. Counter-Current Heat Exchange

8. Co-Current Heat Exchange

9. Energy Turnover in a Grate Cooler

10. Cooler Efficiency h cooler
Q combustion air S Q loss h cooler = =
Q clinker from kiln S Q clinker from kiln

12. Tube Cooler

13. Problems of Conventional Grate Coolers
Uneven clinker distribution
“Red River”
Air breaking through (“Geyser”)
Overheated / burnt plates
Thin clinker bed
Poor UG-compartment sealing
-> Poor recuperation (low hth)

14. Benefits of Modern Cooler Technology
Smoother cooler operation
More stable kiln operation
Good recuperation (high hth)
Control of “Red River”
Less or no clinker fall through
Smaller waste air system
Less space required
(Lower power consumption)

15. Fixed Grate Coolers SF Crossbar Cooler (FLS Fuller) Main Features
First radically different grate cooler!
Fixed line; no moving rows
Mechanical flow regulators; 1 per plate
Crossbars for clinker conveying
Standard modules; pre-installed
Different speeds across width possible
Size < 45 t/d m2
Air installed: ~2.0 Nm3/kg

16. Influence on clinker composition Influence on burning process
Influence of Ratio on burning Process and Chemical Composition
Influence on clinker composition
Influence on burning process
Up and down
Ratio
C3A C4AF
C3A C4AF
C3S C2S
Free lime will increase
C3S C2S
Difficult to
burnا
Lower Clinkering
Temperature
Lower clinker
Clinker reaction accelerated
Difficult to burn
Easy to burn
high
Low
High
1-Silica ratio
SiO2 =
Al2O3+ Fe2O3
2-Alumina ratio =
Al2O3
Fe2O3
3-Lime saturation factor =
CaO
2.8SiO Al2O3+0.65Fe2O3 Or
2.8 SiO2+0.65Al2O3+.35Fe2O

21. 5 Stages of Hydration Reaction Stage Kinetics of Reaction
4/26/2017 6:53 AM
5 Stages of Hydration
Reaction Stage
Kinetics of Reaction
Chemical Process
1. Initial hydrolysis
Chemical Control : Rapid
Dissolution of Ions
2. Induction Period
Nucleation control : low
Continued dissolution of ions
3. Acceleration
Initial formation of hydration products
4. Deceleration
Chemical and diffusion control : Slow
Continued formation of hydration products
5. Steady State
Diffusion control : Slow
Slow formation of hydration products
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

22. 4/26/2017 6:53 AM
Stage 5: Densification/ Steady Stage (can continue for years) Start of belite reactions and they can continue for years. Belite reactions also produce C-S-H and CH, forming a solid mass. Longer length of this stage gives: •Greater concrete’s strength •Lower permeability •Greater durability To promote continued hydration, moisture must be retained in the slab as long as possible
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

23. 4/26/2017 6:53 AM
Factors Affecting Hydration Major factors :- • Chemical Composition of Cement • Cement Type • Sulfate Content • Fineness • Water/Cement Ratio • Curing Temperature • Effects of SCMs and Admixtures
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

24. 4/26/2017 6:53 AM
Mechanism of Heat generation Reaction of calcium Silicates : 2 C3S + 7H  C3S2H8 + 3CH H= J/g 2 C2S + 7H  C3S2H8 + CH H= J/g Reaction of tri calcium aluminate C3A + 3 CSH H  C6AS3H H = J/g
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.