New Developments in Compounding Biomaterials
Prof. Daniel Schwendemann Dep. Head of IWK Institute of Material Sciences and Plastics Processing University of Applied Sciences Eastern Switzerland, Rapperswil
Content IWK - Institute of Material Science and Plastics Processing Overview of the Compounding systems Process needs, machine requirements New developments in Compounding Feed Enhanced Technology Feeding of Liquids Injection Nozzles Side Degassing Project presentation “FluidSolids” 2 New Developments in Compounding Biomaterials
Welcome to the Hochschule für Technik, Rapperswil Part of the University of Applied Science Eastern Switzerland
3 New Developments in Compounding Biomaterials
Biomaterials / Biopolymers Biomaterials: Biopolymers as PLA, PHA (PHB), Starch, etc. Biofibers/Biomass as Cellulose, Hemp, Flax, Woodfibers etc.
Material performance (concerning processing): Shear sensitive
->
low shear
Temperature degradable
->
low temperature
Moisture sensible
->
good degassing behavior
Processed in water
->
high moisture content
4 New Developments in Compounding Biomaterials
Typical steps in plastics processing
Raw Material
Material Handling
Compound ing
Injection Molding
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Testing
Compounding systems
Single screw extruders
Co-rotating
counter-rotating
not intermeshing
intermeshing
+
+
Multiple screw extruders
Twin screw extruders
Buss-Kneader
+
+
+
+
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+
+
Bulk material handling Bulk materials are solid goods, the behavior could vary between solid goods and liquids
solid
bulk
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liquid
Bulk material handling
Bridgebuilding or flow problems in the hopper
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Feed section design Feed section: feed limitation Wrong design
Correct design
Filter bag Feeder
Bulk density 0,25 g / dm³
Specially fine powders are catching a lot of additional air in the feeding pipe.
Filter bag feeder
Filter bag
Bulk density 0,08 g / dm³
Filter bag
Extruder
Extruder
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Co-rotating Twin Screw Extruder / process section
𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿 =
𝐿𝐿 𝐷𝐷𝑎𝑎 10
New Developments in Compounding Biomaterials
Scale up – Influence of cooling and heating Cooling or heating surface versus volume or throughput 30
60.00
25
50.00 Area in sqm/40 D
Do
20
40.00 Volume in l/40 D
Di
15 a
𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 =
𝐷𝐷𝑎𝑎 𝐷𝐷𝑖𝑖
30.00 Ratio l/sqm
10
20.00
5
10.00
0
0.00 25
40
50
58
70
92
Screw diameter in mm
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Scale up factor based on ZSK 25
Feed Enhancement Technology FET: Technology to increase the throughput of feed limited products
Solids conveying is improved by applying vacuum in the feed zone to a wall section which is porous and permeable to gas
This wall section is realized by an insert with a filter membrane installed in an open barrel.
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FET Installation possibilities
In the feed section of the ZSK upstream of the feeding point
In the feed section of the ZSK downstream of feeding point
FET can only be used for solids conveying!
ZSB
ZSK
In the side feeder (ZS-B)
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FET Mechanism
air
FET insert
vacuum
Effects: • air is removed higher bulk density • friction is changed in the area of insert
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Filter cake: compacted powder
FET Mechanism
FET nicht aktiv Angle of conveying approx. 20°
low
Friction and higher bulk density increase the conveying angle: Conveying angle
FET aktiv Angle of conveying approx. 40°
high
Q=F*H*n*ε*η*γ
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capacity
FET Mechanism
SEI can be reduced by: • increasing capacity at same screw speed • reducing screw speed at same capacity
Capacity [kg/h]
SEI4
SEI4 < SEI1
SEI3
with FET SEI2 SEI1
without FET
screw speed [min-1] 16 New Developments in Compounding Biomaterials
Biobased Materials processed with water Steps in material preparation for the compounding process
Biobased Materials processes in water
Biobased Materials processes in water
Drying step (Milling)
Drying step (Milling)
Powder Dosing
Compounding
Dosing Liquids
Compounding with a high amoumt of water
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Challenges with water based fillers X% Filler + H2O
By adding Filler and water into the extruder, the water evaporates and cools the polymer down. Energy input is needed, that the aggregate state of the polymer doesn’t change. Polymer should not “freeze”
Polymer Extruder Heating Capacity
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Water Vapor
(Energy input caused by conveying or mixing is not calculated.)
End product
Compounding water based Fillers/Fibers A calculation tool Input 3.5% Fiber + H2O Quantity Density Volumetric Flow
ρ V
Mass Flow
m
Room Temperature Operating Temperature Melting Point Enthalpie (20°C to 100°C) Specific Heat Capacity
T1 T2 Ts
Heat Flows of: Heating Capacity Polylactide Input NFC+H2O Output Water Vapor End product Temperature Endproduct
Fiber+H2O 100 1.2 3.76 4.51 0.00125 20 200
Fiber 3.5
H2O 96.5
0.16 0.00004 20 200
4.35 0.00121 20 100
Δh cp
Hh Hp Hin Hw Hpnfc t
melted Polymer Polymer
Final Product
3.00 0.00083 20 200 150-160
3.16 0.00088
2591000 4092.78
1550
Unit Result 3549.94 180.00 0.00 3537.70 192.24
W W W W W
200.00
°C
4185
Compound 5.00 NFC
Unit % kg/dm3 l/h kg/h kg/s °C °C °C J/kg
1200
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J/kgK
Compounding water based Fillers/Fibers Needed Heat Capacity for Fibrous-Suspension 4000
3500
Heat Capacity [W]
3000
2500
end product 1% NFC, mp=3kg/h
2000
end product 3% NFC, mp=3kg/h end product 5% NFC, mp=3kg/h
1500
1000
500
0 0
5
10
15
20
Quantity Fibrous Material in Input [%]
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25
Injection Nozzle Technology Injection Nozzle
pump pressure
extruder pressure
spring preload
the spring load must be adjusted according to the extruder pressure to prevent entering of melt
extruder pressure
≤
spring preload
for opening, the pump pressure must be bigger than the spring preload
spring preload
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≤
pump pressure
Injection Nozzle Technology
liquid flow
The lifting of the needle creates an annular gap. Only a small axial movement of the needle is necessary to create the full crosssection area.
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Injection Nozzle Technology Characteristics for throughput 500 3/ 3mm;Water
450
2/ 2mm; Water
Throughput [kg/h]
400
6/ 3 mm Oil
5/ 2mm;Oil
350 300
8/ 1,7mm;Oil+SpringsLoads 1/ 1 mm; Water
250 7/ 1,7mm;Oil
200
4/ 1mm; Oil
150 100 50
Problem Lab-Scale!!!
0 0
10
20
30
40
50
60
Pressure [bar]
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70
80
Degassing of the process section / Side Degassing Unit
Venting Port
Picture Coperion 24 New Developments in Compounding Biomaterials
Project «FluidSolids» Process optimization Compounding Goals
Analysis of the current process Optimization of system configuration (screw design, position of feeding, process parameters, …) Operating tests Partners
FluidSolids AG, Zürich Funding
Public and Private
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Project: FluidSolids® - Impressions
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Project: FluidSolids®
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Project: «FluidSolids®» Umweltpreis der Schweiz 2016 Environmental Award of Switzerland 2016
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Project «FluidSolids»
Summer 2016 New Compounding Plant starts in Switzerland
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Project «FluidSolids»
Extrusion trials at the IWK Lab
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Thank you very much for your attention!
Prof. Daniel Schwendemann IWK Compounding/Extrusion University of Applied Sciences Eastern Switzerland
[email protected] +41 55 222 4916
