Treatment of Carbon Fiber Waste and Recycling Products

Transcription

1 Treatment of Carbon Fiber Waste and Recycling Products Prof. Dr.-Ing. Dipl.-Chem. Marco Limburg Unit of Technologies of RWTH Aachen University ISWA World Congress WGER Meeting Novi Sad 2016

2 CFRP Production and composition Build Matrix Fiber Sizing Elements Material Function Fiber Carbon Stability Matrix Plastic [epoxy resin] Form Sizing Organic connector Connection of fiber and matrix Carbon-deutschland.de, fortis-saxonia.de 13 von 52

3 Waste fractions

4 Production residues Typical mono factions Material A - Prepreg Anlage 0, ,1 Asche 0,2 Flüchtige C-fix Wasser Material B - Prepreg 38,2 60,9 0,3 0,6 Material C - Dry-Fiber 0,6 4,1 95,1 0,2 Material D - Laminate 6,99 30,5 62,1 0,4 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Portion [Mass-%] 15 von 52

5 Products Mobility and construction 4 von 52

6 Products Sport and hobby 5 von 52

7 Products Lifestyle 6 von 52

8 Products and construction Comparison Steel - Carbon 7 von 52

9 Products and construction Textile concrete Carbon layer in textile concrete 8 von 52

10 Waste fractions Production residues Production Products Buildings Industry Consumer Mono-fractions Recycling No residual waste! Separate collection! Thermal treatment of too short fibers Recovery In which plants? 30 von 52

11 Material characteristics Thermal treatment

12 Thermal treatment Influencing variables Residence time Fiber purity versus Fiber stability Atmosphere Temperature 17 von 52

13 Thermal treatment Muffle furnace Photos of Prepreg samples after treatment at 700 C Educt 10 min Mass loss 55 % 40 min Mass loss 96% 90 min Mass loss 99,5% 18 von 52

14 Thermal treatment Parameters and effects: Temperature 400 C, 90 min 550 C, 40 min 670 C, 20 min 21 von 52

15 Thermal treatment Parameters and effects: Residence time and atmosphere 670 C + 5 min Ox 670 C, no Ox, double time 670 C + 20 min Ox 22 von 52

16 Thermal treatment muffle oven, microscopic imaging Influence temp. and residence time Dry Fiber Intact fiber Ø 8µm 700 C 10 min residence time [after heating] 90 min residence time 23 von 52

17 Thermal treatment muffle oven, microscopic imaging Influence temp. and residence time Dry Fiber Oval holes No reduction in diameter Ø 8µm 800 C 10 min residence time [after heating] 24 von 52

18 Thermal treatment muffle oven, microscopic imaging Influence temp. and residence time Dry Fiber Oval holes No reduction in diameter Ø 8µm 900 C 10 min residence time [after heating] 25 von 52

19 Thermal treatment muffle oven, microscopic imaging Influence temp. and residence time Dry Fiber Fiber decomposed Thin fiber splinters 900 C 26 von 52

20 Thermal treatment TGA Influence of atmosphere Temperature [ C] Temperatur Mass [%] 200 N₂ Luft time [s] 61 von 68

21 Thermal treatment TGA Influence of atmosphere Temperature [ C] Temperatur Mass [%] 200 N₂ Luft Time [s] 62 von 68

22 Thermal treatment Mass loss Residue [Ma-%] Resiodue [Ma-%] A B C D Prepreg Prepreg Dry Fiber Laminate C 700 C 800 C 900 C C 700 C 800 C 900 C 10 min (+ Heating time) 40 min (+ Heating time) 42 von 47

23 Recycling

24 Recycling Options Mechanical recycling chopping and milling of CFRP materials no fiber length preservation no separation of matrix and fiber Solvolysis chemical decomposition of matrix materials preserve and reclaim full fibers matrix recovery? Thermal treatment [pyrolysis] thermal decomposition of matrix materials preserve and reclaim full fibers 32 von 52

25 Recycling Pyrolysis Example: CFK Valley Stade

26 Recycling CFK Valley Stade Scheme Secondary crushing Product loading Pyrolysis oven Material feeding on grid plates 34 von 52 [cfk-recycling.com]

27 Recycling CFK Valley Stade Material Feeding on grid plates 36 von 52

28 Recycling CFK Valley Stade Sluice to the pyrolysis oven Grid plates 37 von 52

29 Recycling CFK Valley Stade Inside the oven Smoke vent Roll system 38 von 52

30 Recycling CFK Valley Stade Feed on Grid plate Secondary combustion chamber Fume extraction Pyrolysis gas T > 500 C process heating via exhaust recycling 39 von 52

31 Recycling CFK Valley Stade Oven exit 40 von 52

32 Recycling CFK Valley Stade Product loading 41 von 52

33 Recycling CFK Valley Stade Products 42 von 52

34 Recycling CFK Valley Stade Product configuration Cut fibers Cut/miled products rcfrp Fleece rcfrp-pellets 43 von 52

35 Conclusion

36 Conclusion Carbon fibers are a growing industry The waste streams will come!!! Disposal problems remain unsolved Incineration in waste incinerators problematic No fully developed recycling processes - Downcycling even with perfect processing unavoidable - Complex interaction of residence time, temperature, atmosphere, matrix material, Options for future disposal Strict separation of waste factions [no disposal via residual waste] Higher quality of recycling by - Improvement of processes - Labeling and declaration of ingredients Testing of thermal treatment facilities for disposal potential [WtE hazardous waste incineration cement works] No disposal of small fibers in concrete parts Design to recycle? CFRP 51 von 52

37 Thank you for your attention Prof. Dr.-Ing. RWTH Aachen University Aachen