Différents types de broyeurs utilisés en industrie

une analyse détaillée des différents broyeurs utilisés en cimenterie

1. Fundamentals on
Grinding Workshops
GRINDING I – Training Session

2. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 2
Content
•Fundamentals on grinding
•Different types of ball mills
•Vertical mills
•Roller press
•Horomill

3. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 3
Content
•Fundamentals on grinding
•Different types of ball mills
•Vertical mills
•Roller press
•Horomill

4. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 4
Why do we grind in the cement business?
•To create surface area for good chemical reactions
to occur
•Combination in the kiln (Raw grinding)
•Hydraulic reactions in the concrete (Cement grinding)
•Good combustion in the kiln flame (Coal grinding)

5. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 5
Where do we grind in the overall cement
manufacturing process
Quarry Storage
Fuel
Grinding
Raw
Grinding
Combustion
Cement
Grinding
Storage

6. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 6
What are the main challenges for cement
production
•Reduce power consumption
•Maximize production
•Optimize and improve product regularity
•Control maintenance costs

7. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 7
Grinding costs money
•Grinding uses approx.
60% of plant electricity
•Cheap power is no longer
true
Répartition des kWh dans une cimenterie
Broyage
ciment
42%
Autres
39%
Broyage cru
19%
0 €/MWh
20 €/MWh
40 €/MWh
60 €/MWh
19981999200020012002200320042005200620072008
•Today plant electricity bill is more important than
fuel bill
Specific power must be improved

8. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 8

9. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 9
Grinding costs money
•Costs of wear parts increasing
•Joint visits between process and maintenance
departments upgrade the efficiency: wear takes place in
the process
TOTAL WEAR FROM 1998 TO 01-2004
TOTAL WEAR FROM 02-2004 TO 04-2004
PLN raw mill example:
• Change of iron source
• Wear before and after use
of this new raw material
• Material stays in the reject

10. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 10
The different types of mill
•Three different mill types with specific purposes
•Raw mills (for slag, shale, limestone…)
•Size reduction (targeted rejects at 90 and 200µm)
•Drying the materials
•Cement mills (pure or compound cements)
•Size reduction (objectives in SSB)
•Management of gypsum dehydration
•Fuel mills (coal and pet coke)
•Size reduction (targeted rejects at 90µm)
•Drying the materials

11. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 11
Technologies and arrangements
•Different mill technologies
•Ball mills
•Air swept mill = materials released by ventilation air
•Compound mill = with end discharge
•Bi rotator mill = with central discharge
•Vertical mill
•Roller press
•Horomill
•Different architectures
•In open circuit
•In closed circuit
•With pre-grinding, hybrid grinding…

12. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 12
Origin of a current workshop
•Existing workshop design depends on
•Material feed specifications
•Feed size
•Moisture
•Outlet product specifications
•Flow rate
•Fineness target
•History of the plant and workshop

13. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 13
Content
•Fundamentals on grinding
•Different types of ball mills
•Vertical mills
•Roller press
•Horomill

14. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 14
The Ball Mill

15. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 15
The Ball Mill
•Compound with two compartments
Inlet head
Fresh feed +
Separator
Rejects
chute
Fresh air inlet
Inlet trunnion
C1 liners
C2 liners
Supports
Intermediate diaphragm
Shell
Central ventilation ring
Outlet diaphragm
Gas + dust
outlet
Discharge box
Outlet seal
Material discharge

16. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 16
The ball mill in open circuit
Dust
Collector
Mill
Fresh
Feed
Finished Product
Fan
gas
material

17. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 17
The ball mill in open circuit
•Advantages
•Moderate investment costs
•Simple operation
•Simple maintenance
•Highest reliability
•Disadvantages
•little or no control of fineness
•not adapted to high fineness (possibility of overgrinding)
•broad particles size distribution
•higher temperature of products
•Limited drying capacity

18. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 18
The ball mill in closed circuit
Gas
Mill
Dynamic
Separator
Dust
Collector
Fresh
Feed
Finished Product
Rejects
Static
Separator
Dust Collector
Material
Fan Fan

19. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 19
The ball mill in closed circuit
•General description
•Better regularity thanks to a real control of the fineness
•High fineness is possible
•Higher flexibility and possibility of optimisation by product
•Higher output, better efficiency
•Possibility of higher mill ventilation
•Better temperature control
•High mill ventilation
•Possibility to have a separated ventilation in the separator
•Narrow particle size distribution
•Higher investment costs

20. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 20
The Bi-rotator Mill

21. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 21
The Bi-rotator Mill
Drying chamber
Grinding
chambers
Central
discharge
Air
Material feed
Material feed (separator rejects)
Air

22. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 22
The Bi-rotator Mill in closed circuit
Gas
Mill
Dynamic
Separator
Fresh
Feed
Finished Product
Rejects
Static
Separator
Dust Collector
Material Fan

23. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 23
•Advantages
•High ventilation capacity for drying materials
•Disadvantages
•False air
The Bi-rotator Mill

24. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 24
The Air-Swept Mill
Air
Grinding
chamber
Material
Air + material
Drying
chamber
Intermediate
diaphragm

25. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 25
The Air-Swept Mill in closed circuit
Gas
Mill
Dynamic
Separator
Fresh
Feed
Finished Product
Rejects
Dust Collector
Material
Fan

26. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 26
•Advantages
•High ventilation capacity to dry materials
•Disadvantages
•High specific power consumption due to swept solution
The Air-Swept Mill

27. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 27
Content
•Fundamentals on grinding
•Different types of ball mills
•Vertical mills
•Roller press
•Horomill

28. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 28
The Vertical Mill
Separator
Drive
Fine Product
HE Separator
Rejects Cone
Feed Material
Air or Hot Gases
Mill Drive
Grinding Roller
Port ring
Hydraulic
tensioning
cylinder
Pressure
frame
Grinding Table

29. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 29
The Vertical Mill in closed circuit
Hot Gas
&
Vapour
Fresh Feed
Cyclone
Roller Mill
Fan
Main Baghouse
Vent Fan
Roller Mill
Hot Gas
R
e
c
ir
c
u
la
t
io
n

E
le
v
a
t
o
r
Product Flow 1 Product Flow 2
(Coarse Rejects)
closed circuit

30. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 30
The Vertical Mill
•Advantages
•Good efficiency factor
•High drying capacity
•Combined grinder, separator and dryer in one unit
•Popular for coal and raw material grinding with high
moisture content
•Disadvantages
•Complex operation
•Reliability – maintenance costs
•Vibrations
•Management of gypsum dehydration in cement grinding

31. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 31
Content
•Fundamentals on grinding
•Different types of ball mills
•Vertical mills
•Roller press
•Horomill

32. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 32
cylinders
fixed roller
Floating roller
reducer
universal joint
accumulators
feed
flake
Roller Press

33. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 33
Roller Press
• Pneumatic slide choke plates on
both sides of feed hopper needed to
control intake and therefore power.
• Low reliability typical, but very
energy efficient.

34. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 34
Roller Press
•Advantages
•High efficiency factor
•Compact installation
•High production increase when used as pregrinding
•Disadvantages
•High investment costs
•Complex operation
•Reliabilty
•Limited drying capacity

35. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 35
Pregrinding with Roller Press
•Basic pregrinding
•Preground material could feed into an intermediate bin
•Approx. 30% increase of production
•Recirculation is required for pregrinder efficiency and stability
Feed
Fines
Recir-
culation

36. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 36
Pregrinding with Roller Press
•Hybrid pregrinding
•Separator rejects are split (partly to ball mill and pregrinder)
•Approx. 50% increase of production
•Difficult to control
Recir-
culation
Feed
Fines
Reject

37. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 37
Pregrinding with Roller Press
•Combined pregrinding (series)
•Each grinding machine has its own separator
•Up to 100% increase of production is possible
Feed
Semi-finished
Fines

38. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 38
Content
•Fundamentals on grinding
•Different types of ball mills
•Vertical mills
•Roller press
•Horomill

39. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 39
Horomill
•General description
•Horizontal mill
•Single roller inside a motorized tube shell
•Slide shoe (thrust pad) bearings
•Girth gear and pinion drive
•Designed by FCB

40. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 40
Horomill
cylinder
roller
pinion shaft
Scraper and feed
forward plate

41. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 41
Horomill
feed vent
shell
grinding track
roller
cylinder
discharge
slide shoe bearings

42. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 42
Horomill
• Patented device to control
retention time
• RPM > V critical
• Internal recirculation results in
low vibration
17° nip angle
• Greatest nip angle (lowest
amount of pressure)
• Virtually no shear - little
wear claimed

43. Fundamentals on Grinding Workshops
KUJ - July 2012 – Grinding I 43
Ways to upgrade a workshop
•Optimisation of workshop operations
•Ball charge design
•Ventilation balance
•Circulating load
•Increase of the ball mill speed (target of 75% Vcrit)
•Replacement of the workshop separator with a third
generation one