Dr. Paul Andersen COPERION CORPORATION

Dr. Paul Andersen
Director, Process Technology
COPERION CORPORATION
GPCA Plastcon 2013 I April 7-9, 2013 I Page 2
Intermeshing Co-rotating Twin-screw Extruders:
Integrating the Highest Torque Technology with Direct
Extrusion for Improved Productivity
Paul Andersen
Director, Process Technology
Coperion Corporation
Ramsey, NJ
GPCA Plastcon 2013 I April 7-9, 2013 I Page3
Proud Supporter
Overview
• Coperion: Customized solutions are our response
to complex challenges
• Co-rotating Twin-screw Compounder
• Benefits of High Torque Processing
• Benefits of Direct Extrusion / In-line Processing
• Summary
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Coperion: Worldwide market and technology leader Compounding & Extrusion, Materials Handling and Service
Over 130 years experience with mixing and kneading
processes
Pioneering work and continuous development of the
closely intermeshing, co-rotating twin-screw extruder
Over 10,000 compounding systems worldwide
Comprehensive product portfolio: laboratory extruder
ZSK 18 MEGAlab to largest extruder ZSK 420 Mc
Throughput rates from 1 kg/h to 100 t/h
Turnkey compounding systems from raw material
feeding to downstream pelletizing / in-line
handling equipment
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Original Extruder (Date Unknown): David B. Todd Design
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Modular Design: Twin-screw Extruder
Drive power from 10 kW up to 12 MW for rates between 0.5 kg/h and 100 t/h
Motor
Gear box
Process section
Die head
Operating principle
Modular design for screw elements and
kneading blocks
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Characteristic Dimensions: Co-rotating Twin-screws
2-flighted profile
Do/Di: Diameter ratio
Do
Md / a3: Specific torque
Do = Outer screw diameter
Di
Di = Inner screw diameter
a
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a = Center distance
ZSK – Evolution of Torque and RPM
1985: ZSK Sc
Do / Di = 1.55
Md / a3 = 8.7 Nm/cm3
n = 600 min-1
1995: ZSK Mc
Do / Di = 1.55
Md / a3 = 11.3 Nm/cm3
n = 1200 min-1
2004: ZSK Mc PLUS
Do / Di = 1.55
Md / a3 = 13.5 Nm/cm3
n = 1200 min-1
2010: ZSK Mc18
Do / Di = 1.55
Md / a3 = 18.0 Nm/cm3
n = 1200 min-1
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ZSK Mc18: Highlights of latest extruder generation: 2012
Power
Density: 18 Nm/cm3
1.55 Do/Di
geometry
Temperature control for
Maximum energy efficiency:
a) shrink fit barrel liners
b) cartridge heaters
c) optimized cooling system
d) new insulation covers
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FET: Feed
Enhancement
Technology
Screw Shafts
made of new
high performance
materials
ZS-EG
Twin-screw Side
Devolatilization
Benefits of Higher Torque
• Utilize higher % fill factor
OD/ID = 1,55
vu
hmax
• Reduced average shear
gamma = vu /h
• Lower material temperature
• Typically lower residence time
OD/ID = 1,55
vu
hmax
• Reduced stress on product: Improved Product Quality/Energy Efficiency
• Enables utilization of higher screw rpm: Improved Productivity
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Benefits of Higher torque: Processing Undried PET
Step 1: Avoid i.v. degradation
•
PET equilibrium moisture content approximately 0.33 %
• Plastification of „wet“ product  immediate hydrolytic degradation
- 104 times faster than thermal degradation
- ~ 5,000 times faster than thermo-oxidative degradation
Removal of retained moisture is the main problem for
processing / compounding of PET
Options for achieving a low processing moisture content:
• Standard crystallization at 150°C and drying at 150–180°C
• Air-drying process at temperatures of max. 60 °C without crystallization
• Combination of pre-drying or conditioning and vacuum degassing
• Vacuum degassing at extrusion
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Benefits of Higher torque: Processing Undried PET
Step 1a: Compounding to avoid i.v. degradation
1
2
3
4
PET
Atmospheric vent
Vacuum pump
Discharge
2
1
3
4
ZSK Mc18
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Processing Undried PET
Impact of Higher Torque on Rate
40%
Parameters: ZSK 45 Mc18, Md ~ 85%
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Processing Undried PET:
Impact of Higher Torque on Energy
~ 10%
Parameters: ZSK 45 Mc18, Md ~ 85%
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Benefits of Higher torque: Processing Undried PET
Combined 60% Increase in Throughput
0.84
iV [dl/g]
Throughput [kg/h]
350
300
Smaller IV drop
At same screw speed
Raw material
iVo=0.83 dl/g
0.82
60% rate increase
with constant IV
drop
250
0.83
0.81
30%
200
increase
in rate at
same rpm
150
Same IV drop
with 25% higher screw speed
0.80
0.79
0.78
100
200
300
Screw speed [rpm]
Parameters: ZSK 45 Mc18, Md ~ 85%
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400
200
300
Screw speed [rpm]
400
Benefits of Higher Torque: Processing Undried PET
Summary of the Mc18 technology:
• Mc18 ZSK can achieve 30% higher throughput as compared to Mc+
• Higher filling level reduces specific energy
• Reduced specific energy decreases material temperature 5-10°C
• High torque compounder: lower iV drop for high viscosity PET
• For equivalent iV drop, 60% increase in throughput achievable
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Co-rotating Twin-screw Extruders and In-line Processing
PET, PMMA
Thermoforming
High density
sound insulation and
sound deadening
products
Natural and
wood fiber
composites
Honeycomb
catalysts
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Direct extrusion: Combination of Compounding and Extrusion
Process in two steps: standard procedure
Silo
Compoundingplant / extruder
Silo
Meltingextruder
Shaping
die
Semi product
Shaping
die
Semi product
Compounding and in-line-extrusion in one step
Silo
Compoundingplant / extruder
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Benefits of Direct Extrusion / In-line Processing
Improved Quality:
Thermal degradation is reduced
Elimination of second heat cycle
Improved Economics:
Reduction of energy cost
Cooling of intermediate product
Re-heating of intermediate product
Improved Productivity
Faster change over for pigmented resins
No dryer clean out
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In-line processing / Direct Extrusion Applications
• Cast Film/Sheet from PET, PLA
• Film from PVB for compound glass window
• Sheet Extrusion: PMMA for optical applications
• Biaxial orientated film from PP, PET, PLA, PA, or PE
• Foamable sheet from PP or PE
• Sheet for noise reduction out of high filled (EVA, PP, PE, PEO)
• Sheet from PP and wood flour or talc
• Conductive film for the electronic industry
Throughput from 15 kg/h to 12,000 kg/h
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Direct extrusion / In-line Processing Undried PET:
Step 2: Integration of Cast Film Set up
Undried polyester
pellets or recyclate
1
1.
2.
3.
4.
5.
6.
7.
Pellet feeding
ZSK Mc18
Venting
Degassing
Vacuum pump (1-5 mbar)
Melt pump
Screen pack changer
11
4
6
7
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12
5
4
ZSK 119: 2.5 t/h PET
Film die
Chill-roll-plant
Edge trim
Pelletizer
Process control unit
Film thickness control unit
Winder
10
3
2
8.
9.
10.
11.
12.
13.
14.
8
13
9
14
Twin-screw Extruder vs. Drying/Single-screw: PET
• No pre-treatment of feedstock (i.e. crystallization, agglomeration or
predrying), results in energy savings of 30-40%
• High flexibility, fast start up and quick product change over,
( i.e. no dryer clean out is required)
• Minimal iV-drop of about 0.04 dl/g
• Combination of raw materials (pellets) and recycled materials (flakes)
in any ratio without prior agglomeration / crystallization
• Good product homogenity when additives, fillers or color pigments /
masterbatches have to be incorporated
• Effective degassing of residual moisture and monomers/oligomers
• Production at throughput rates even beyond 4 t/h without problems
(i.e. ZSK 133 instead of Ø 250/275 single screw cascade)
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Twin-screw extruder vs. Drying/Single-screw: PET
System capacity
Twin-screw Extruder
Single screw cascade
4,000 kg/h
4,000 kg/h
Installed drive power
Installed capacity dryer
750 kW
998 kW
——
ca. 1,300 kW
Installed capacity vacuum
pump
48 kW
Installed capacity other
equipment, incl. heating
100 kW
Energy consumption in
production
0.22 kWh/kg
0.32 kWh/kg
693,440 €
1,008,640 €
Energy saving p.a. (8,000h)
0.0985 €/kWh
Energy saving 30%
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Plant for the Production of Sheet: PMMA …
1
3
4
5
2
1 Feeding
2 ZSK Mc18
3 Degassing
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4 Calender
5 Cutting device
6 Deposit table
6
Direct Extrusion of Foamable Films: PE, PP ….
2
1
2
3
4
6
7
8
9
1.
2.
3.
4.
5.
6.
Silos
Feeders
ZS-B twin screw side feeder
Liquid silo
Liquid pump
ZSK Mc18
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12
10
5
11
7. Start-up valve
8. Sheet die
9. Calender
10.Thickness gauge
11.Edge trimming device
12.Film winder
7
Summary
 Flexibility – High Torque Twin-screw Compounder
is adaptable to multiple applications
 Economic efficiency
– Coupling compounding with in-line extrusion
minimizes costs and maximizes product quality
 Reliability – Processing of un-dried PET is commercially proven
 Productivity – High throughput with good product quality
 Quality – Minimal iV loss occurs with PET
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