RECYCLING OF THERMOSET POLYMER COMPOSITES

Transcription

1 RECYCLING OF THERMOSET POLYMER COMPOSITES Professor Mikael Skrifvars School of Engineering University of Borås Presentation at: Svensk Kompositforskning 2014, Lund, April 2-3, 2014 RECYCLING OF FIBRE-REINFORCED COMPSITES Recycling is not straightforward due to the combination of reinforcing fibres and the resin matrix into one homogeneous material material. The durability, high strength, long product life length, as well as low weight, are from the environmental point of view positive characteristics. Composite waste volumes are (still) low, especially compared to short life length materials. Why bother? 1

2 RECYCLING CLASSIFICATIONS Secondary recycling? 1. Primary recycling conversion to material with equivalent properties and same value 2. Secondary recycling conversion into material with inferior properties and lower value 3. Tertiary recycling conversion into chemical raw materials 4. Quaternary recycling conversion into energy WHY DO WE RECYCLE MATERIALS? Avoid landfilling High material value Material scarcity Environmental reasons (pollution, littering) Availability of waste materials RECYCLING IS PROMOTED BY: Legislation Disposal fees and deposits Recycling infrastructure Environmental product design Ship demolition in Bangladesh 2

3 RECYCLING OF COMPOSITES - FACTORS TO CONSIDER: 1. Waste types: Production waste End-of-life products 2. Waste volumes Geographical distribution By type/composition 2. Composition Glass fibres/carbon fibre Thermoset/thermoplastic resin 4. Type of application and use Product size Combination with other materials 5. Product life length END-OF-LIFE VEHICLES (ELV) Stena Metall site in Halmstad Sweden Cars before fragmentation Mixed metals Automotive shredder residue (FLUFF) RECYCLING OF ELVS Regulated by the End-of-LifeVehicles directive 2000/53/EC: In 2015: 85 % of car weight reused or recycled 10 % of car weight incinerated with energy recovery 5 % of car weight can be disposed in landfills MATERIAL COMPOSITION IN CARS: 65 to 75 % metals 25 to 35 % plastics, glass, rubber and textiles, of which major part remains as automotive shredder residue (ASR or fluff ) Increased composite volumes will force implementation of recycling 3

4 PRODUCTION WASTE FROM COMPOSITE MANUFACTURING Composite manufacturing is characterized by rather much production waste Short life length Many materials such as resin, left over reinforcement, off-cut trims, buckets, brushes, vacuum bag film and sealant, tubes, gloves, packaging material etc Sorting at site is necessary High glass fibre content, with low energy value VOLUMES? wt-% of production volume European transport sector: Production waste kt/a END OF LIFE COMPOSITE PRODUCTS Wind mill blade at end-of-life due to failure Estimate: Current in operation wind mill blades will be replaced in 20 years, giving tonnes/a from 2020 and tonnes/a from 2034 Medium to very long life length Many different products: consumer and industrial Any size and shape possible Large variation in material composition Often combined with noncomposite materials Contamination and material degradation during use possible Some waste types regulated by directives and legislation 4

5 ECRC European Composite Recycling Services Company A European recycling concept introduced 2003 Co-operation between composite companies Fee based: membership fee and recycling fee Technical development of recycling methods Recycling at recycling centres in Europe Current status is un-known, most likely not in action! Recycling Processes for Thermoset Composites Mechanical Processes Thermal Processes Chemical Processes Grinded Powders Fibrous Products Incineration with Energy Recovery Fluidised Bed Processes Pyrolysis Solvolysis Fillers Energy Pyrolysis Oils Reinforcements Recovery of Fillers and Reinforcements Chemicals and Resins 5

6 MECHANICAL RECYCLING OF COMPOSITES Primary and secondary recycling Size reduction, fragmentation and fractionation Use as filler or reinforcement in virgin composite products, or other materials Recycled glass fibre composite difficult to compete with virgin materials due to cost Certification of recycled material necessary ERCOM - a concept for composite recycling Duration SMC and BMC parts from automotive 2 million parts were recycled Used a mobile shredder to collect end-of-life automotive composite parts Project ended in 2004 due to lack of profitability 6

7 RECYCLED COMPOSITE BOAT CONCEPT Made in 1990 at SICOMP, Piteå 20 wt-% recycled composite with the recycled composite as a central layer in the laminate The recycled composite applied as a resin-mixture by using special spray lay-up equipment Cost and performance similar as for conventional boats RECYCORE Development in A reinforcement material containing recovered glass fibers Layer structure: Virgin reinforcement Recovered glass fibers Virgin reinforcement Developed by SICOMP and Ahlstrom 1 25 mm recovered fibre length weight-% recovered fibre content 7

8 END OF LIFE BOATS - COLLECTION OF LEISURE BOATS IN FINLAND Finnboat rf and Kuusakoski Recycling Oy Started 2005, ongoing Totally leisure boats in Finland, 1000/a are disposed 26 collection points GF composite boats Wooden boats Wood GF composite boats ABS boats (PUR with freon as floating material) Process: Pretreatment, Grinding, Separation, Reuse, Landfill 100 to 200 boats annually ABS can be material recycled Wood used as fuel GF landfilled due to low quality and value Metallic components recycled Main goal to take care of the boats to prevent them from lying around at coast line COST FACTORS IN MATERIAL RECYCLING OF COMPOSITES Waste sorting for fragmentation Collection and sorting Size-reduction/Pregrinding/compression for transporting Transportation Interim storage before processing Transportation to processing plant Processing: Sorting Fragmentation Fractionation Quality control Packaging Transportation for reuse Use in primary or secondary product 8

9 THERMAL RECYCLING PROCESSES Data from VAMP 18 project Quaternary recycling method 1. Direct incineration of composite waste: The glass fibres will remain in the ash, while the resin is used as fuel 2. Incineration with material recovery Glass/carbon fibres can be collected for reuse Fluidised bed 3. Pyrolysis with material recovery Thermal decomposition in oxygen free environment The resin is converted to a pyrolysis oil, while the fibres can be collected for reuse Microwave heating MOBILE COMPOSITE INCINERATOR CONCEPT Japan, appr

10 VAMP 18 project SICOMP et al. Duration Full scale incineration trial of end-of-life composites: Aircraft CFRP Leisure boats PVC sandwich SMC Glass-mat thermoplastic Incineration in waste incineration plants 9 to 35 MJ/kg heat value for the composite waste PhD thesis by Anna Hedlund-Åström KTH - Royal Institute of Technology, Stockholm, 2005 FLUIDISED-BED RECOVERY OF AEROPLANE STRUCTURES Controlled incineration leaving reinforcement intact Trials by SICOMP

11 RECYCLING OF WIND TURBINE BLADES Since 2001 Energy recovery and material recovery No activities today? ReFiber Danmark FLUIDISED-BED CONCEPT FOR RECOVERY OF GLASS FIBRES FROM COMPOSITES University of Nottingham, UK Bed temperature 450 C 1.3 m/s fluidising velocity 5 mm fibre length with 80 % purity 50 % reduction of fibre tensile strength 9000 tonnes/year scrap composite for break even CF composites can also be treated Will be implemented in airplane CF recycling Pickering, S. et al., Composites Science and Technology, 60 (2000)

12 COMPOSITE RECYCLING IN CEMENT KILN Cement production requires high energy fuels, in order to form the cement Composite waste can be used as a fuel feedstock The resin provides the fuel, while the reinforcement remains in the cement as a filler Endorsed by European Composites Industry Association (EuCIA) 1 ton resin = 600 kg coal Cement manufacturers use commonly energy rich waste as fuel in the process RECYCLING OF WIND MILL BLADES AS CEMENT FUEL Zajons Zerkleinerungs GmbH, Melbeck, Germany Since 2010 Capacity: tonnes/a Dust free fragmentation by humidification Co-operation with Holcim PrimeSub cement raw material CompoCycle - label 12

13 LUMI Recycling of composite waste in cement manufacturing Production waste from Finnish composite industry Trials at Finnsementti Oy, Lappeenranta site: 124 collected, which gave 96 t grinded Mixed with other energy rich waste (20 wt-%) Problems seen: Fragmentation and grinding to right size High glass content gives a rather low energy value STENA METALL AND UNIVERSITY OF BORÅS EU LIFE07 ENV/S/ MICROWAVE PYROLYSIS Thermochemical decomposition without oxygen Organic molecules are cracked to smaller molecules, which can be used as chemical feedstock The material is heated by microwaves Suitable for materials with poor thermal conductivity Valuable inert metals can be collected 13

14 LAB SCALE REACTOR 3000 W, 10 l PILOT SCALE REACTOR W microwave power W electrical heating kg/h capacity Continuous process Microwave passing into reactor main difficulty OBTAINED PRODUCTS 70 % recovered glass fibres 17 % pyrolysis oil 13 % pyrolysis gas (CH 4 ) ADHERENT TECHNOLOGIES, NEW MEXICO, USA Vacuum cracking process: Thermal decomposition of resins (no gasification) Small and mobile units possible Reinforcements and fillers can be collected Pilot scale: kg/hr Developed for waste size reduction Wet chemical breakdown: CF composites are treated with a liquid and the CFs can be collected for reuse 95 % of original strength Pilot scale: 50 kg batch 14

15 CHEMICAL DEGRADATION OR SOLVOLYSIS The resin is dissolved/hydrolysed while the fibres are collected for reuse The decomposed resin can be collected and used as chemical raw material Adesso Advanced Materials, Wuxi, China Recyclable epoxy resin system Recycloset epoxy resin Cleavamine curing agent Chemical recycling at C Fibres collected and reused Resin collected from solvent as powder, which can be used as toughening agent in moulding compounds 95 % fibre recovery rate 15

16 EURECOMP project FP7, Solvolysis of composite waste Supercritical water: 221 bar and 374 C Thermochemical hydrolysis under pressure 95 % of resin is removed, clean fibres with no sizing are obtained Mechanical properties are reduced by 20 % Liquid fraction can be used as chemical raw material Composites Part A: Applied Science and Manufacturing, Volume 43, Issue 3, 2012, M A I Carbon R&D cluster in in Bavaria, Germany with 70 partners CF recycling based on: solvolysis, developed by Siemens (200 C, supercritical water) Pyrolysis Electrodynamic fragmentation , 3.2 million EUR Audi, BMW, SGL Carbon, Siemens, To create an integrated recycling process, with optimized recycling methods _inno_1316_1.htm 16

17 ELG Carbon Fibre Ltd Recycled Carbon Fibre Developed since 2003, from 2008 commercial process Continuous pyrolysis process 2000 tonnes/a CF composite waste Dry fibres, cured and uncured prepregs, laminates Processed into unsized milled and chopped fibres Properties 90 % of virgin CF Waste handling service small compensation paid for dry CF MSc-thesis: Reduction of Environmental Impact Effect of disposing Wind Turbine Blades Behzad Rahnaman, Högskolan på Gotland, 2011 Use as artificial reefs constructions Use in building constructions as architectonic elements 17

18 CONCLUDING REMARKS Thank you for your interest! Recycling of glass fibre composites technically possible, but not cost effective Destruction of glass fibre composites in cement manufacturing possible, if logistics solved Carbon fibre composites have higher recycling potential due to higher material value Recycling of composites must be addressed in the product design phase of composite manufacturing 18