1. 10/11/2011 2011 ACS Rubber Division 180 th Technical Meeting Kneader Technology for the Direct Devolatilization of Temperature Sensitive Elastomers Boyd T. Safrit, PhD, PE Andreas E. Diener, Dipl. Ing.

2. 10/11/2011 – p. 2 Conventional Process  Polymerization exothermic  Temperature control important  Polymer temperature sensitive  Viscosity increases with MW build   Solution polymerization  Stirred tank reactors  Steam stripping for solvent removal

3. 10/11/2011 – p. 3 Conventional Process Solution Polymerization Stripping Separation Confectioning Coagulation Expeller Expander Belt dryer Water / steam consumption, solvent recovery Air handling and emissions Plant footprint, maintenance

4. 10/11/2011 – p. 4 Conventional vs. Direct Devolatilization Solution Polymerization Stripping Separation Confectioning Coagulation Expeller Expander Belt dryer Main Evaporation Finishing

5. 10/11/2011 – p. 5 Kneader Technology

6. 10/11/2011 – p. 6 Kneader Technology

7. 10/11/2011 – p. 7 Main Evaporation  Cement feed of 75-90% solvent  Maximum temperature of 100°C  High energy duty for solvent evaporation   Back mixed kneader reactor  Discharge target of 2-10% solvent  High mechanical energy input

8. 10/11/2011 – p. 8 Finishing  Pasty feed of 2-10% solvent  Maximum temperature of 100°C  High viscosity  high mechanical energy  overheating of elastomer   Plug flow kneader reactor  Discharge target of 200-2000 ppm solvent  Process elastomer as crumbles (or pasty phase)

9. 10/11/2011 – p. 9 Two Step Process for Direct Devolatilization  Installed at Fraunhofer Gesellschaft, Schkopau, Germany  Part of larger semi works plant for polymer synthesis, production, and testing

10. 10/11/2011 – p. 10 Main Evaporation Experimental  100 liter single shaft kneader reactor  Residence time of 15 minutes  Shaft speed of 50-80 RPM Elastomer Solution 400 kg/hr 10% BR 100°C Pasty Elastomer Hot Oil 80°C 300 mbar Hot Oil

11. 10/11/2011 – p. 11 Finishing Experimental  200 liter twin shaft kneader reactor  Residence time of 30 minutes  Shaft speed of 60 RPM Pasty Elastomer Crumbly Elastomer 60 mbar 40 kg/hr Hot Oil 80°C Hot Oil

12. 10/11/2011 – p. 12 Main Evaporation Temperature Profile Thermal Input Mechanical Input Thermal Output Energy Required Feed

13. 10/11/2011 – p. 13 Main Evaporation Energy Balance Solvent Evaporation 35 kW 27 kW (77%) mechanical energy Elastomer Solution 300 mbar ~65 °C (estimated) 400 kg/hr 10% BR 100°C Pasty Elastomer 44 kg/hr 90% BR 97°C 8 kW (23%) thermal energy

14. 10/11/2011 – p. 14 Finishing Energy Balance 60 mbar Devolatilization 0.5 kW 4.6 kW mechanical energy Pasty Elastomer 40 kg/hr 1000 ppm Solvent 87 °C 44 kg/hr 90% BR 97°C Crumbly Elastomer 4.1 kW thermal energy

15. 10/11/2011 – p. 15 Finishing Improved Mass Transfer Process

16. 10/11/2011 – p. 16 Finishing Improved Mass Transfer Process Finisher sizeCapacityfinal VOCtotal volatiles 7 liter2.5 kg/hr< 10 ppm5000 ppm 30 liter30 kg/hr< 50 ppm5000 ppm 100 liter50 kg/hr< 50 ppm5000 ppm 200 liter50 kg/hr< 15 ppm5000 ppm  BR in hexane  Atmospheric pressure

17. 10/11/2011 – p. 17 Comparison to Conventional Process  Energy  Environment  Flexibility  Operation  Footprint  Quality

18. 10/11/2011 – p. 18 Conclusion  Conventional process for temperature sensitive elastomers Mature and proven technology Several key disadvantages  Two step process for direct devolatilization Kneader reactor technology Removes water from process Demonstrated process on semi works scale