new rubber devolatilization opportunities (direct

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New Rubber Devolatilization Opportunities (Direct Desolventizing) Opportunities (Direct Desolventizing) Enabled by Unconventional Technology

George E. Schlager

P d t M LIST AGProduct Manager LIST AG

57th Annual General Meeting of the International Institute of Synthetic Rubber Producers (IISRP)

New Orleans, USA, April 11‐14, 2016

New Orleans 2016 57th AGM

Agenda

• Kneader reactor technology

• Devolatilization kinetic model

• Commercial process comparison

• Two step kneader process

• Product development of Rubber manufactures

• Conclusion / Summary

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LIST COMPANY

• Private Company

• > 450 Installations

• 100 Employees (60 Engineers)

• Manufacturing by Strategic Partners

• Quality Assurance by LIST

• Fully equipped R&D Facility


Heinz List Vision back in 1966:

“Processes in the concentrated phase are considerably more efficient than processes

in the diluted phase and therefore also significantly more economical.”

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KneaderTechnology

• Excellent Mixing & Kneading

• Large Heat Exchange Surfaces

• Efficient Renewal of Phase Boundary Layers

• Effective Self-Cleaning

• Large Working Volumes


1 m

• High Torque Applications

• Wide Range of Shear Rate

• Plug Flow

• Batch & Conti

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KneaderTechnology Single Shaft Example

V l tilF d V l il VaporVapor

Connections VolatilesFeed Volatiles

ProprietaryDisks with

Mixing El t

High StrengthHeated Housing

High StrengthHeated Shaft

VaporConnections with large

Cross SectionalArea

Connections with large

Cross SectionalArea


Discharge

Cross Sectional

ViewSide View

ProprietaryCounter Hooks

Elements

Twin Shaft ExampleVideo

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Conventional vs. Direct Devolatilization

Solution Polymerization

Stripping

Separation

Coagulation

Expeller

Main Evaporation

Finishing

Water & Steam

Consumption /

Solvent recovery

Footprint / Maintenance

Confectioning

Expander

Belt dryer

Finishing

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Air handling and emissions

Overall Process Flow Diagram

Pre-Concentration

Condensation / Recovery


Main EvaporatorReactor

(Optional)Recovery


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Finisher

Confectioning

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Main Evaporation

• Cement feed of 75-90% solvent

• Maximum temperature of 100 – 130 °C

• Back mixed kneader reactor

• Discharge target of 2-10% solvent

• High energy duty for solvent evaporation

• Challenges to design a solvent evaporator process:

• Featuring maximal contact heat input

• Use mechanical heat input dissipation to further increase capacity

• High mechanical energy input

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• Use mechanical heat input dissipation to further increase capacity

• Prevent foam development, which inhibits contact heat input and plugs vapor lines

• Exhibiting maximal flexibility regarding evaporation capacities and polymer grade

Main Evaporation – DevelopmentExperimental & Process Simulation

Continuous back‐mixed reactor

Feed 1Feed 2

Feed 3Feed 4Continuous back‐mixed reactor

Viscous mass

Main Evaporator

CSTR

Feed 4

Heat transferHeat transfer

Torque (50 %)Torque (100 %)

Multiple feed port – CSTR cascade model Experimental development <‐> process simulation and

calculations

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Cement Feed Rate on Kneader Shaft Speed

35

40

45

5

10

15

20

25

30

35

[kg/h

]

1 feed port:

2 feed ports:

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0

5

0 0.5 1 1.5

[Hz]RPM

30 60 90

Conclusions – Main Evaporation

• Model developed to predict evaporation capacity using CSTR cascade RTD

• Improved process using multiple feed ports

• Good agreement between prediction and observed feed distribution

• Improved product handling (foam)

• Flexibility of polymer grades

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Finishing

• Definition:• Removal of volatile components from polymer stream (e.g. non reacted monomer or solvent)

• Process Challenge:• Final product temperature control• Avoid shear• Minimize residence time (maximize process efficiency)• Achieve final volatile specification

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• Pasty feed of 2-10% solvent

• Maximum temperature of 100 – 130 °C

• High viscosity high mechanical energy overheating of elastomer

• Plug flow kneader

• Injection of stripping media for devol & temperature control

• Discharge target of < 200-2000 ppm solvent

Finishing – Liquid Injection

• Enhanced mass transfer

• Low partial pressure of solvent

• Atmospheric pressure (absolute pressure determines total VOC content)

• Temperature control through evaporative cooling

• High shaft speed possible without overheating product

• High product fill possible without overheating product

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product

• Final temperature independent of residence time

• VOC content mainly water (strip medium), which typically is acceptable to customers

R&D – 160l Scale up Finisher

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Finishing – Liquid Injection

Off Gas

• Axial conveyance is largely independent of shaft speed

• Significantly lower shear than extruder

Liquid injection

• Suitable for diffusion-limited processes requiring long residence times

• Large free volume

• Low vapor velocity, no particle entrainment

• Process flexibility

• Feed conditions

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LIST FinisherProduct

• Capacity (high turn down ratio)

Two Step Process for Direct Devolatilization

• Installed at Fraunhofer Gesellschaft, Schkopau, Germany

• Part of larger semi works plant for polymer synthesis, d dproduction, and testing

• Applicable for scale-up testing

• Detail Engineering completed for 40kty

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Comparison to Conventional Process

Operation Cost

Stripping Technology Direct DevolatilizationTechnology

Operation Cost Energy Consumption higher lower Plant Operation higher lower Plant Cleaning Effort higher lower Solvent Purification higher lower

Environmental Off Gas cleaning (Incineration) necessary not necessary Waste Water cleaning higher lower

May 5, 2008 17

Product Quality• low temperature; low shear higher lower• continuous steady state condition worse better

Opportunities – Devolatilization – high cis

Product development of Rubber manufactures

High Performance Tires High Performance Polymers High high cis (99+) and low low cis polymers Driving force for catalyst development

High cis PBR (99+) – linear Polymer

High cis high stickiness High stickiness higher viscosity during polymerization Hi h i it d rin p l m riz ti n l r r bb r n ntr ti n (7%) High viscosity during polymerization lower rubber concentration (7%) Lower rubber concentration Less effectiveness in processing

High stickiness = bad coagulation High stickiness = bad mechanical dewatering High stickiness = bad drying

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• Opportunity to produce new grades -> flexibility on market trends and demands

• Improve product temperature control -> quality

Conclusion / Direct DevolatilizaitonTechnology Benefits

• Less space required

• Minimize solvent separation step - environmently sound

• Less utility consumption –> less OPEX –> higher profits

• Less maintenance cost -> less cleaning efforts

• Less off-spec materials

• Less solvent losses (VOC’s) – 100% closed system with LISTLess solvent losses (VOC s) 100% closed system with LIST

• Less routine replacement parts

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Thank you


new rubber devolatilization opportunities (direct

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