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Advance Systems, Inc.
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Getting More Performance from an Existing Extrusion Coating Dryer - - PowerPoint PPT Presentation
Getting More Performance from an Existing Extrusion Coating Dryer - - PowerPoint PPT Presentation
Advance Systems, Inc. Getting More Performance from an Existing Extrusion Coating Dryer William R. Henry Session 5, Paper 1 2 Getting More Performance from an Existing Extrusion Coating Dryer INCREASE LINE SPEED
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Getting More Performance from an Existing Extrusion Coating Dryer
INCREASE LINE SPEED
- INCREASE THROUGHPUT EFFICIENCY
- DECREASE ENERGY CONSUMPTION
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ZONE 1 ZONE 2
- 2 zones, 96OC,74OC
- Velocity = 1524 m/min
- Length = 4.6 m
- Line speed = 305 m/min
- 11 microns, PP
- A-131-X, 2.4% solids
- 99% dry, 38oC
- EVAP Load = 595 MJ/hr
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INCREASE LINE SPEED
- Distribute drying load
- Increase exhaust air
- Use Drier air
- Improve web stability
- Increase air velocity
- Increase air volume
- Decrease nozzle-to-web gap
- Decrease nozzle spacing
- Pre-Heat web
- Distribute Drying Load
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ZONE 1 ZONE 2
96oC 74oC
ZONE 1 ZONE 2
80oC 91oC
Zone 1 Zone 2 Total MJ/hr 96 C 74 C 595 80 C 91 C 594
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INCREASE LINE SPEED
- Distribute drying load
- Increase exhaust air
- Use Drier air
- Improve web stability
- Increase air velocity
- Increase air volume
- Decrease nozzle-to-web gap
- Decrease nozzle spacing
- Pre-Heat web
- Increase exhaust air
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ZONE 1 ZONE 2
- Increase exhaust air
UNITS BASE MODIFIED
exhaust rate
m3/min
122 225 air temperature
- C
96/74 96/74 energy usage
MJ/hr
595 930 line speed
m/min
305 312 exit coating solids % 99 99
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- Use dry make-up air
ZONE 1 ZONE 2
UNITS BASE MODIFIED
air humidity
kg/kg
0.015 0.012 air temperature
- C
96/74 96/74 energy usage
MJ/hr
595 598 line speed
m/min
305 313 exit coating solids % 99 99
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- Improve web stability
Lateral movement of web may show at higher line speeds
ho
ho ~ k V2/3
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- Increase air velocity
ZONE 1 ZONE 2
UNITS BASE MODIFIED
air velocity
m/min
1524 1824 air temperature
- C
96/74 96/74 energy usage
MJ/hr
595 688 line speed
m/min
305 335 exit coating solids % 99 99
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- Increase air volume
UNITS BASE MODIFIED
nozzle slot width
mm
3.18 4.76 air temperature
- C
96/74 96/74 air volume
m3/min
219 329 line speed
m/min
305 335 exit coating solids % 99 99
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- Decrease nozzle-web gap
ZONE 1 ZONE 2
Nozzle-to-web gap
UNITS BASE MODIFIED
nozzle-web gap
mm
25.4 19.0 air temperature
- C
96/74 96/74 energy usage
MJ/hr
595 595 line speed
m/min
305 334 exit coating solids % 99 99
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- Decrease nozzle spacing
Nozzle spacing
UNITS BASE MODIFIED
nozzle spacing
cm
17.8 12.7 air temperature
- C
96/74 96/74 air volume
m3/min
219 306 line speed
m/min
305 335 exit coating solids % 99 99
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- Pre-heat web
ZONE 1 ZONE 2
infrared heaters
UNITS BASE MODIFIED
inlet web temp
- C 21
32 air temperature
- C
96/74 96/74 air volume
m3/min
219 219 line speed
m/min
305 354 exit coating solids % 99 99
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INCREASING THROUGHPUT EFFICIENCY
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- Even temperature profile
Uneven temperature distribution may indicate uneven heating or mixing of the air supply
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- Even temperature profile
Cooler Air FROM Dryer Hot Air TO Dryer BURNER FAN
Push-thru Plenum
Cooler Air FROM Dryer Hot Air TO Dryer BURNER
Pull-thru Plenum
FAN
A “pull-thru” heat plenum will thoroughly mix the air
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- Even temperature profile
Static mixer Turning vanes
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- Even velocity profile
Like air temperature, the velocity profile has a direct bearing on heat transfer to the web
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- Even velocity profile
Distribution hole plates
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- Even exhaust draw
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- Reduce coating/web defects
- spread out drying through entire dryer
- achieve even drying across web width
- maintain stable web to reduce edge
damage or web breaks
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DECREASING ENERGY CONSUMPTION
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- Lower temperature – same speed
UNITS BASE MODIFIED
air humidity
kg/kg
0.015 0.008 air temperature
- C
96/74 82/60 Nozzle-web gap
mm
25.4 20.3 air velocity
m/min
1524 1676 energy usage
MJ/hr
595 361 line speed
m/min
305 305 exit coating solids % 99 99
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- Avoid over drying
Measure (IR sensor) and CONTROL the existing web temperature to ensure that the product is sufficiently dry but not TOO DRY.
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- Insulate
Prevent heat loss - ADDITIONAL insulation may be internal or external
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- “Negative” dryer pressure
Internal pressure inside the dryer enclosure should be slightly lower than the outside pressure. Excessive air flow INTO or OUT OF the dryer is a needless energy loss.
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Getting More Performance from an Existing Extrusion Coating Dryer
INCREASE LINE SPEED
- INCREASE THROUGHPUT EFFICIENCY
- DECREASE ENERGY CONSUMPTION
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Advance Systems, Inc.