Welding Alloys Technical Seminar for Cement Industry Gebr. Pfeiffer Vertical Roller Mills Bodrum Turkey, May 2012
Part 2 MPS and MVR Mills Modernisation of old MPS mills Directives for coal grinding plants SLS Classifier Pressure accumulator technology
Design features of the PFEIFFER MPS mill
MPS and MVR
MVR vertical roller mill MPS vertical roller mill www.gpse.de
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Design of MPS mill
fine product
raw material
hot gas
reject material www.gpse.de
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Design of MPS mill
seal air piping pressure frame pull rods pressure yokes grinding rollers grinding table nozzle ring reject scrapers hot gas channel maintenance drive reject chute hydraulic cylinders foundation frame mill motor
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Design of MPS mill
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Design of MPS mill
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grit cone pressure frame feed material Lift-andSwing-System grinding roller nozzle ring air or hot gases
gear box www.gpse.de
grinding plate
hydraulic tensioning cylinder
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MPS design feature : : maintenance drive
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Mainte Mai ntenan nance ce Dri Drive ve::
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MPS design feature: Liftable grinding rollers
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Direct start without auxiliary drive Use of standard motor possible, 2nd shaft end not required Easy emptying of mill Inner grinding roller stop to keep roller in position of track during lifting
MPS design feature: Liftable grinding rollers
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Clearance in strap joints provides the flexibility degrees of freedom for the grinding operation Outer strap limits roller inclination to 12°during lifting
MPS design feature: Torque support
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Reduced dynamic forces
MPS design feature: Torque support
intermediate bolts
shock absorbing unit www.gpse.de
pressure frame
Flow of force via intermediate bolt onto shock absorbing system
Absorption of transverse force via sliding bearing of intermediate bolt
Bearing sealing provided by seal air (passive)
Housing limit stop
MPS design feature : : Wear protection
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MPS design feature : : rising gas velocity
Profile of gas velocity
140 % 115 % 105 % 100 %
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MPS design feature : : Lift - -and a nd - -Swing Swing System
Replacement of rollers and wear parts
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Design features of the new PFEIFFER MVR mill for grinding high throughput rates
MPS and MVR
MPS vertical roller mill
MVR vertical roller mill www.gpse.de
Design of the MVR mill
MVR mill – main function groups
SLS classifier Housing with nozzle ring and hotgas duct Grinding table Grinding rollers Innovative roller suspension Twin support Active Redundancy Standardization benefits through common parts One hydraulic system for operation and maintenance drive train options
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Conventional drive up to 7 000 kW
MultiDrive ® up to 12 000 kW
Design
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Roller suspension
• Roller module consists of • Roller with cylindrical wear parts • Roller axle • Roller arm • Bearing stand • Hydraulic tensioning cylinder • Articulation piece, fork head and anchorplate • Two roller modules side by side on a common twin support
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Roller suspension
• Guided motion – smooth run • Grinding gap always in parallel • Positive effects on energy transmission • Tension cylinder also swings out roller for service www.gpse.de
Roller suspension
Rotation axis under maintenance operation
Two roller modules side by side on a common twin support
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Roller suspension
60 °
Advantage in plant layout: Wide angle between supports due to parallelly shifted axles
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Modular drive design with MultiDrive
Up to 12,000 kW with up to 6 identical drive modules. The drive modules are a Siemens/Flender standard products, no special MultiDrive design. With only 3 different drive modules the complete power range can be covered – strategic spare saving.
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Further MultiDrive advantages
- Reduced height requirement, lower feed point - Bigger diameter of axial thrust bearing, thus operation with minus 1 or 2 rollers possible. - Table support designed to take unbalanced radial forces
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Parallel grinding gap , symmetric tyres
Parallel grinding gap in any operating point www.gpse.de
Symmetric design allows the tyres to be flipped over
Grinding elements exchange
Hydraulic control unit www.gpse.de
MVR mill
Unchanged
Changed / Improved
• Process Design
• Capacity Range
• Safety Factors
• Number of rollers
• Levels of spec.
• Roller Suspension
grinding force
• Flat Table
• Nozzle ring
• Cylindrical Rollers
• Gas Velocity Design
• Parallel Grinding Gap
• Classifier
• MultiDrive ® with variable speed
• Wear Protection
• Active Redundancy
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The PFEIFFER - -MVR M VR roller mill Essential design features Active Redundancy Up to 6 grinding rollers and 6 drive modules: mill operation continues even if a roller or drive module is under maintenance.
Hydraulic system for operation and maintenance For maintenance purposes no extra component is required to swing the rollers out of the mill.
Parallel grinding gap The geometry of the grinding elements in combination with our MVR suspension system ensures a parallel grinding gap in any operating point.
Modular drive design Up to 12 000 kW with only 3 different types of drive modules. A mill can be equipped with up to 6 identical drive modules.
Symmetric wear parts The modular roller system with only 5 roller modules and symmetric tyres provides capacities of up to 1 000 t/h. For an extended lifetime tyres can be turned in case of wear.
Space saving twin support 1 support for 2 roller modules for ease of maintenance work. www.gpse.de
MVR 6700 C - -6 6 cement mill
Country
Iran
France
Ecuador
Italy
Turkey
India
China
MPS size
MPS 4250 BC
MPS 4750 BC
MPS 4250 BC
MPS 4250 BC
MPS 4750 BC
MPS 5600 BC
MPS 5600 BC
91% clinker 4% limestone 5% gypsum
71% clinker 25% fly ash 4% gypsum
100% slag
64% clinker 62% clinker 18% slag 35% pozzolana 7% limestone 3% gypsum 6% gypsum 5% pozzolana
94% clinker 6% gypsum
96% clinker 4% gypsum
Throughput rate, tph
122
100
120
126
151
305
128
Fineness (acc.Blaine), cm²/g
3000
4300
4000
4400
3800
3500
5000
18
24
17
14
19
16
32
415
310
430
530
390
460
230
Mixture
Spec. power consumption, (Mill), kWh/t Calculated throughput with MVR 6700-C6 www.gpse.de
Summary - References
MVR 400 Germany MVR 1800 Germany MVR 3750 BosniaHerzegovina
MVR 5600 plus MultiDrive ® MultiDrive ® France
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Modernisation and upgrading of MPS mills
Possible Modernisation Measures
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Lift-and-Swing System
SLS high efficiency classifier
New components
Grit extraction screw conveyor
Upgrading by Pfeiffer Lift - -and and - -Swing Swing System
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Upgrading by Pfeiffer Lift - -and and - -Swing Swing System
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Short downtime
Safe and easy handling
One maintenance door only
Low space requirement
Upgrading with SLS classifier
classifier classifier type SLF
replaced by
by choice
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classifier type SLS
Upgrading with SLS classifier
Votorantim for Santa Rita works, Brazil MPS 3450 before after upgrading upgrading product rate:
180
220 t/h
absorbed power:
1340
1430 kW
(mill)
power consumption: 7.4 (mill)
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6.5
kWh/t
Full scale upgrade Gorazdze Cement in Poland
Gorazdze Cement, Gorazdze, Poland MPS 4150
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Full scale upgrade Gorazdze Cement in Poland
Classifier replaced
Pressure frame and hydraulic unit replaced
Rollers replaced
Nozzle ring replaced
Gearbox replaced www.gpse.de
Full scale upgrade Gorazdze Cement in Poland
Operating results
(t/h)
(kWh/t)
%R0,09mm
Before upgrading:
300
4.5
18.0
Guaranteed values:
440
4.3
18.0
After upgrading:
461
4.5
15.8
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Upgrading by grit extraction to redundant ball mill La Cemento National, Ecuador Guayaquil
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Upgrading by grit extraction to redundant ball mill La Cemento National, Ecuador Guayaquil
Finished product Finished product
Classifier Classifier grits www.gpse.de
Upgrading by grit extraction to redundant ball mill La Cemento National, Ecuador Guayaquil
Operating results
before
after
upgrading
upgrading
380
520
t/h
-
125
t/h
3600
3630
kW
9.4
9.2
Product rate:
Extraction rate
Absorbed power (MPS mill) Power consumption: (MPS mill)
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kWh/t
New directives for the design of coal grinding plants (Based on EU standards)
Test of explosion pressure shock resistance filter housing with explosion flap
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Design of coal grinding plants
Coal characteristics Common range Lower Explosion Limit (LEL)
15 – 125 g/m3
Maximum Explosion Pressure (MEP) Maximum Rate of Explosion Pressure Rise
6 - 10 bar 40 – 140 bar m/sec
Limiting Oxygen Concentration (LOC)
12 - 16 %
Volatile Matter (VM)
15 - 35 %
The exact data are needed for rating the explosion venting!
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Design of coal grinding plants
safety concept
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Explosion-pressure-shock-resistant design of mill and classifier of up to 3.5 bar Decoupling of explosion areas through rotary locks, flame traps and safety shutoff dampers. Explosion venting (free and/or absorbed) Monitoring of CO, O2, dust emission and temperature
Central vacuum cleaner for the building
Inerting and fire fighting by CO2 flooding
Safety relevant measuring points
2
Temperature 3
3
2
1
Temperature 1 CO level O2 level (plants operated under inert conditions)
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Dust emission CO level O2 level
Design of coal grinding plants
Safety concept
End-user classifies his plant into zones of explosion risk
No risk of explosion in mill building thanks to central vacuum cleaner
Necessity of defining explosion characteristics of coal
Explosion pressure venting at mill inlet and outlet
Dust emission measurement after filter
Extra efforts in project documentation, manuals available at authorities
Authorities assess conformity of machines with directive, especially mills not operated under inert conditions
Increased efforts in quality control, including parts manufactured locally
Equipment procured by end-user must comply with directive
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Design features of the PFEIFFER SLS classifier
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High efficiency classifier SLS
SLS classifier
the high efficiency lamella type classifier for Pfeiffer MPS mills
different types designed for different applications SLS-B: for standard applications (cement raw material, limestone, etc.) SLS-BF: for very fine products (< 5% residue on 90 µm) SLS-BK: for coal and petcoke mills SLS-BC: for cement mills, slag mills and mills for cement additives
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High efficiency classifier SLS
drive
fine product
feed material
rotor
louver
grit cone
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High efficiency classifier SLS
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detail of annular gap
gas outlet duct
annular gap submerged pipe three-part wear ring separating rotor www.gpse.de
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High efficiency classifier SLS
material inlet
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High efficiency classifier SLS
electromechanical drive
reliable
easy to maintain
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Basic knowledge about pressure accumulators to avoid damages
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Photos
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