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Computer Modeling in Today’s Converting World
AIMCAL Europe Web Coating Conference
Prague, Czech Republic June 11, 2012
Advance Systems, Inc.
Manufacturers – What We See…
Substrates • Paper • PET • PP • BOPP • Foil • Laminates
Solvents • Water • MEK • Toluene • Ethyl Acetate • Acetone
Manufacturers – What We Do…
• Combine Operating Parameters • Design a dryer
– Successful – Cost Effective – The First Time!
• Review Drying Process • Process Variables • Dryer Types • Dryer Comparisons • Information Necessary for Design • Examples • Conclusion and Questions
Agenda
Hot Air Source Introduces Heat For Evaporation
Pa Turbulent Air
Laminar Layer
Coating
Web
Pc
Mass Transfer
Figure 1
Btu Into Web From Hot Air
Turbulent Air
Laminar Layer Coating (Solvent & Solids
Web Substrate
Ta
Tc
Heat Transfer
Figure 2
Factors that Affect Drying
• Temperature of Supply Air • Nozzle Velocity of Impingement Air • Air Volume • Proximity of Nozzle to Web • Nozzle Pitch
Process Variables • Substrate
• Material • Thickness or Weight
• Solvent • Aqueous • Volatile
• Coating • % solids • Coat Weight
• Production Speeds • Process Restrictions
• Evaporation Rate • Substrate or Coating Temperature
Y mm
X mm
Roll-Support
Figure 3
Typically 50-100cm
Typically 19-38cm
Flotation
X mm Typically
25 - 38cm
Typically 6 - 9.5 mm
Air Bar v Slot Nozzle P
RE
SS
UR
E V
ELO
CIT
Y IN
INC
HE
S W
. C.
Pressure velocity profiles for slots and air bars
Air bar Slot
Figure 5
Substrate: 50 micron PET Speed: 305 mpm Coating: 2 gsm dry % Coating Solids: 5 Solvent: Water
Dryer Comparison
Effective Length
Pitch
Projection
Air
Temp
Nozzle
Velocity
Fan Power (per Zone)
Heat Load
Exit Web
Temp
Supply Volume
(per zone)
DRYER
(mt)
(cm)
(cm)
°C
Mt/sec
Kw
MJ/hr
°C
Standard mt3 /min
Roll
Support
17.7
19
5.1
315
30.5
14.0
5800
95.8
170
Flotation
12.9
38
0.6
315
33.0
11.5
4850
104.9
130
Dryer Comparison
Air Bar Examples
Photo 1
Product Specification One
• Substrate: Paper • Weight: 150 gsm • Web Width: 1500mm • Web Speed: 300 mpm
• Dry Coat: 5 – 10 gsm • Solvent: MEK, IPA,
Toluene (equal blend) • % Coating Solids: 15
Product Specification One
Product Specification One
Product Specification Two
• Substrate: Paper • Weight: 150 gsm • Web Width: 1500mm • Web Speed: 300 mpm
• Dry Coat: 5 – 10 gsm • Solvent: MEK, IPA,
Toluene (equal blend) • % Coating Solids: 15
0
20
40
60
80
100
120
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0.0 3.0 6.1 9.1 12.2 15.2 18.3 21.3 24.4 27.4 30.5 33.5 36.6 39.6 42.7 45.7
% C
oatin
g So
lids
Web
Tem
pera
ture
- °C
Dryer Length - Meters
Solvent Coating 150 gsm paper, 10 gsm dry, 15% solids, MEK, IPA, Toluene, 300 mpm
WEB TEMPDEG CCOAT SOLIDSPCT
Zone One Temp: 82°C Counterflow
37% LFL
Zone Three Temp: 66°C Counterflow
37% LFL
Zone Two Temp: 49°C Counterflow
37% LFL
Zone Four Temp: 107°C Counterflow
30% LFL
Zone Five Temp: 107°C
Velocity: 20.3/38.1 mt/sec 30% LFL
Product Specification Two
Product Specification Two
Coat Weight Change - Ramifications
• Coat Weight Ramifications – Increased Zone Quantity from 3 Zones to 5 Zones
• Increased Length by 18 mts • Increased Cost • LFL’s • Pollution Control
– Increased Exhaust Volume
• Substrates – 100-200 gsm – 12-200 microns – Paper, PET, Foil
• Coat Weight – 1-20 gsm
• % Solids – 25-50%
Process Ranges
High Speed Silicone Cure
• Multiple Zones • Goal: Get Web to Cure Temp Quickly • “Easy Part:” Hold Web at Cure Temperature • Multiple Zones
• Flexibility with Supply Temperature • Short Heat Up Zones • Longer Cure Zones
• Varied Nozzle Pitch • Reduced Overall Cost
• Reduce Zone Quantity?
Silicone Cure
Custom v. Standardized: Silicone
• Custom Configuration – Heat Up Zones
• Two (2) @ 4.9 mts
– Cure Zones • Three (3) @ 7 mts
• Total Length – 31 meters
• Standard Configuration – Heat Up Zones
• Two (2) @ 5 mt
– Cure Zones • Four (4) @ 5 mt
• Total Length – 30 meters
Silicone Cure
Issues with Single Zone Silicone Curing • Overheating Product
– Wastes Energy – Could Damage Substrate or Coating – Cooling After Cure More Difficult
• Reduce Temperature – Slow Production Speed – Product Not Properly Cured
Silicone Cure
Silicone Cure
Benefits of Two Zone Silicone Curing • Flexibility
– More Temperature Control • More Energy Efficient • Use IR Sensors to “Prove” Cure • Use the Energy You Need • Less Likely to Damage Substrate or Coating
Silicone Cure – Two Zones
Summary • Invaluable Tool • Budgeting
– Project Justification – Operating Parameters
• Pollution Control
• Material Handling • Process Set Up
– Temperatures – Velocities – Volumes
Summary
• Web Information – Material – Thickness – Width – Desired Speed
• Process Limitations – Evaporation Rate Limit – Web Temperature Limit – Coating Temperature Limit
• Coating Information – Wet or Dry Coat Weight – % Coating Solids – Solvents
Acknowledgements
• Special thanks to Randy Sanders from ASI for his help with this paper
