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  • Recycling polypropylene carpetsIn association with Carpet Recycling UKFunded by Envirolink NorthwestJane Gardner

  • Presentation SummaryProject aimsTypes of carpetCurrent recycling routesDemonstration trial resultsEconomic assessmentProject conclusions

  • Project aimsTo develop a process for recycling polypropylene carpets To assess commercial viability of the process

  • UK Carpet sustainabilityOver half a million tonnes/year of carpet enters the UK waste streamRecycling rate currently less than 2%Carpets have high carbon footprint due to use of virgin materials big sustainability gain if recycled

  • Carpet materialsPolymers: Polypropylene (PP); Polyester/Polyethylene terephthalate (PET); Nylon; Chalk-filled elastomers; Natural fibres: Wool; and Hessian/Jute.

  • Types of carpet - wovenMade by weaving the carpet pile into warp fibres with a loom fibres can be polyester or PP, whilst the pile tends to be PP

  • Types of carpet - tuftedPile fibres attached to a backing layer fibres - wool or PP Elastomer compound bonds fibres to the backing layerSecond backing layer made from hessian or manmade fibre such as PP

  • Carpet recycling initiativesAmerica:CARE Carpet America Recovery Effort founded 2002Europe late 1990s: RECAM - Recovery of Carpet MaterialsCRE - Carpet Recycling Europe Polyamid 2000 in Germany UK late 2000s:Greenback RecyclingReeds Carpets exhibition/temporary floors

  • Existing end marketsTypically low valueEquestrian surfaces additive to sand based all weather surfaces

    Plastic cannot be recovered once used as equestrian surfaceOther applications:Horticultural market

  • Axion recycling trialsNIR ID sortingSize reductionScreeningExtrusion

  • Size reductionGranulation15mm screenAlternative options:ShearingShredding

  • Granulated PP carpet

  • Screen to remove dust, finesHigh energy flip-flop screen12x12mm deckAlternative techniquedry cleaning

  • Screening resultsOversized fraction cleaner and less dusty than feedHigh yield loss - due to screen size of granulator (15mm) relative to flip-flop (12mm)For 12mm flip-flop - granulator needs to be 20-25mmFor 15mm granulator screen - flip-flop needs to be 6-8mm

    Target fractionNon-target fractionLossesOversizedUndersized-38%59%3%

  • Lab scale extrusionSorted PP carpet samples:Post industrialPost consumer

    Material prepared for extrusion by partial melting then granulation

  • Extrusion problemsInitial batch of carpets could not be extrudedPresence of un-melted fibres made from different polymers nylon and PETProblem due to different types of carpet woven and tuftedSecond batch of tufted carpet processed successfully

  • Moulded polymerPost industrial injection moulding applicationsPost consumer lower grade injection moulding, for example plant pots and buckets

  • Physical properties

    Physical properties testUnitsPost industrial samplePost consumer sampleMFI (at 230C, 2.16kg)652TensileMpa2223Elong @ Yield%7.310.1Elong @ Break%35.128.8Densityg/cm31.151.023Ash%1710

  • Commercial assessmentFeed stock in Northwest - estimated at over 6,000 tonnes per annum meeting specification of:Tufted construction;Positively identified PP pile and backing fibres;Dry and with no heavy contamination;Suitable for manual handling.

  • Overall recycling scheme

  • Processing option 1

    De-baling stage

    Size reduction stage

    Screening stageYield = 80%

    Extrusion stage Yield = 97%

    5000 te/year ofBaled sorted tufted PP carpetCost 80/te

    5000 te

    120 te

    4000 te

    3880 te of PP pelletSell for 500/te

    Waste to landfill1120 te Disposal cost 60/te

    1000 te

    5000 te

    Power costStage operating 8 hours, 5 days a week

    Power cost Stage operating 8 hours, 5 days a week

    Power cost Stage operating 24 hours, 5 days a week

    Power costStage operating 8 hours, 5 days a week

  • Processing option 2

    Screening stageYield = 80%

    Extrusion stage Yield = 97%

    5000 te/year ofSorted and size reduced tufted PP carpetCost 250/te

    4000 te

    3880 te of PP pelletSell for 500/te

    Waste to landfill1220 te Disposal cost 60/te

    1000 te

    Power cost Stage operating 8 hours, 5 days a week

    Power cost Stage operating 24 hours, 5 days a week

    120 te

  • Payback calculation

    Option 1Option 2Plant capacitytpa75007500Capital costs1,000,000800,000Power/yr266,000254,800Labour/yr277,000241,000Others/yr125,000109,000Total operating costs/yr668,000604,800Feed costs/yr400,0001,250,000Disposal/yr38,10038,100Revenue/yr1,940,0001,940,000Margin/yr833,90047,100PaybackYears1.217.0

  • Technical conclusionsStraight forward processing route:Rigorous PP identification and sortingSize reductionScreeningExtrusion

    Finished PP: Good physical properties, Suitable for use in medium to low grade applications, Eg injection moulded plant pots

  • Commercial conclusionsCritical success factor - correct identification of all polymer fibres within the carpet

    Economics of the recycling process are promising

    Next step: Commercial scale testing

  • Axion ConsultingTudor HouseMeadwayBramhallSK2 2DG0161 426 7731

    *****Woven Carpet Notes Woven carpets are manufactured by weaving the carpet pile onto other fibres with a loom. Woven carpets tend to contain a range of coloured yarns to produce intricate patterns. The manufacturing process also tends to be quite slow. The fibres onto which the carpet pile is woven can be polyester, whilst the pile itself tends to be PP. *Tufted Carpet Notes Tufted carpets are the most common type for use in domestic applications. They are manufactured by attaching the pile fibres to a backing layer, the tufts are individually inserted into a lattice backing layer by a needling technique. The pile fibres can be natural materials such as wool or synthetic materials such as PP. A latex compound is then used to bond the fibres to the backing layer. A second backing layer is added to the carpet, sometimes this can be made of hessian but it can also be manmade fibres such as PP. The second backing layer provides stability and strength to the carpet.

    *Existing Recycling Techniques NotesAmerica CARE mission is to develop market based solutions for recovering value from post consumer carpets Over 80% of the carpets handled by CARE were made from nylon and only 8% were PP. Carpets in America also tend to have deeper piles than UK carpets Recycling technologies developed in the USA typically involve shearing of the pile from the carpet backing, rather than shredding or granulation. For example, InterfaceFLOR in Georgia, America, has a recycling process which shears off the pile fibres from the carpets. The main focus for the process is the recovery of nylon 6 and 66 for use in new carpet tiles, but a PP fraction is created by the process which is then sold on.

    Europe The RECAM (Recovery of Carpet Materials) Project. The aim of RECAM, which was funded by the European Community, was to develop an economically feasible, closed loop system for post consumer and post industrial carpet waste. The project studied the collection, identification and sorting of carpets as well as the recovery of high grade materials and energy from residual fractions. The project was completed in 1999;

    Development of the technology. This involved finding or developing the necessary technical equipment and tools for the recycling process. One element of this was COCARE, a coding system to allow for easy identification of carpets; and

    Pilot plant. Carpet Recycling Europe (CRE) was established in 1998 with the aim to implement the findings from the RECAM project. The project involved the building of the first automated sorting plant for carpets in Mainz, Germany. It was the intention of the project to use the pilot plant to gather data to allow for an economic, technical and environmental assessment of the carpet recycling process. The plant was able to process approximately 3.5 tonnes per hour. Although the plant demonstrated technical feasibility, the economic conditions were unfavourable, due to landfill being the cheaper option at the time. Because of this the plant closed in August 2002. The project concluded that although technically feasible, carpet recycling would require more favourable economic conditions for the process to become viable.

    In Germany in 1999 Polyamid 2000, the largest nylon 6 carpet recycling facility, was built. The plant reclaimed post consumer carpet from all over Europe and utilised chemical depolymerisation and re-polymerisation of nylon 6 and extrusion compounding of nylon 66. The plant also recovered PP which was sold for use in fibre reinforced concrete panels. Again due to difficult economic conditions and a lack of suitable feed material the plant shut in June 2003.Reeds CarpetsReeds are on the brink of launching a fully recyclable carpet system. The UK exhibition & events industry currently dumps an estimated 12 million square metres of carpet every year - much of it ending up in landfill. Reeds have been working in conjunction with manufacturers and Warwick University to fine tune the manufacturing process to enable the carpet to be converted into mouldab


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