computer modeling in today’s converting world...computer modeling in today’s converting world...
TRANSCRIPT
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
