EPET塑料瓶回收的LCA

Resources,ConservationandRecycling55(2010)34–52ContentslistsavailableatScienceDirectResources,ConservationandRecyclingjournalhomepage::ALCAcasestudyofPETbottle-to-fibrerecyclingLiShena,∗,ErnstWorrellb,MartinK.PatelaaDepartmentofScience,TechnologyandSociety,FacultyofScience,UtrechtUniversity,Heidelberglaan2,3584CSUtrecht,NetherlandsbDepartmentofInnovationandEnvironmentalSciences,FacultyofGeosciences,UtrechtUniversity,NetherlandsarticleinfoArticlehistory:Received11December2009Receivedinrevisedform30June2010Accepted30June2010Keywords:PETrecyclingOpen-looprecyclingPETbottleFlakeLCAEnvironmentimpactMechanicalrecyclingChemicalrecyclingGHGemissionsabstractThisstudyassessestheenvironmentalimpactofpolyethyleneterephthalate(PET)bottle-to-fibrerecy-clingusingthemethodologyoflife-cycleassessment(LCA).Fourrecyclingcases,includingmechanicalrecycling,semi-mechanicalrecycling,back-to-oligomerrecyclingandback-to-monomerrecyclingwereanalysed.Threeallocationmethodsareappliedforopen-looprecycling,i.e.the“cut-off”approach,the“wastevaluation”approachandthe“systemexpansion”approach.Nineenvironmentalimpactindicatorswereanalysed,i.e.non-renewableenergyuse(NREU),globalwarmingpotential(GWP),abioticdepletion,acidification,eutrophication,humantoxicity,freshwateraquaticecotoxicity,terrestrialecotoxicityandphotochemicaloxidantformation.TheLCAresultsarecomparedwithvirginPETfibreandothercom-modityfibreproducts,i.e.cotton,viscose,PP(polypropylene)andPLA(polylacticacid).TheLCAresultsshowthatrecycledPETfibresofferimportantenvironmentalbenefitsovervirginPETfibre.Dependingontheallocationmethodsappliedforopen-loop-recycling,NREUsavingsof40–85%andGWPsavingsof25–75%canbeachieved.RecycledPETfibresproducedbymechanicalrecyclingcauselowerenvironmen-talimpactsthanvirginPETinatleasteightoutofatotalofninecategories.RecycledfibresproducedfromchemicalrecyclingallowtoreduceimpactsinsixtosevenoutofatotalofninecategoriescomparedtovirginPETfibres.Notethatwhilemechanicalrecyclinghasabetterenvironmentalprofilethanchemicalrecycling,chemicallyrecycledfibrescanbeappliedinawiderrangeofapplicationsthanmechanicallyrecycledfibres.©2010ElsevierB.V.Allrightsreserved.1.IntroductionPolyethyleneterephthalate(PET)bottleshaveexperiencedrapidgrowthsincethe1970swhenthetechniqueofblowmould-ingwasintroduced(Glenz,2007).Today,bottlegradePETisoneofthemostimportantpackagingplastics.In2007,theworldwideconsumptionofbottlegradePETwas15millionmet-rictonnes(106metrictonnesorMt)(SimonandSchnieders,2009),representing8%ofthetotaldemandofstandardplastics.1Meanwhile,recyclingofpost-consumerPETbottleshasbecomeawell-establishedsystemwithitsownlogisticchaininclud-ingbottlescollection,flakeproductionandpelletproduction.In2007,approximately4.5MtofPETbottleswerecollectedandrecycledinto3.6Mtofflakesworldwide(Thiele,2009).MostoftherecycledPETflakeswereconvertedintofibres∗Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](L.Shen).1AccordingtoPlasticsEurope’sdefinition,“StandardPlastics”refertostan-dardthermoplastics,includingPE(polyethylene),PP(polypropylene),PVC(polyvinylchloride),PS(polystyrene),EPS(expandedpolystyrene)andPET(bottlegrade).(Fig.1).RecycledPETfibreaccountedforapproximately8%oftheworldPETfibreproductionin2007(JCFA,2008;Thiele,2009).InEurope,theamountofcollectedpost-consumerPETbottlewastehasincreasedfrom0.2Mtin1998to1.26Mtin2008(Petcore,2008),representinganannualgrowthrateofapproximately19%(seeFig.2).About40%ofallusedPETbottlesinEuropewerecol-lectedforrecyclingin2009(PlasticsEurope,2009a).ItisexpectedthatPETbottlewastecollectioninEuropewillcontinuetoincreaseby10%p.a.inthenearfuture(Glenz,2007)(seeFig.2).Theprimarypurposeofthisstudyistounderstandtheenvi-ronmentalimpactsofrecycledPETfibrecomparedtovirginPET.SeveralstudiesreportedtheenvironmentalimpactsofPETrecy-cling(Arenaetal.,2003;Detzeletal.,2004;SongandHyun,1999).Inthesestudies,PETrecyclingwasseenasapost-consumerwastemanagementoptionandwascomparedwithotheroptionssuchaslandfillingandincineration.Thegoalofthisstudyisnottoanal-ysedifferentwastemanagementoptions,buttounderstandtheenvironmentalimpactofmakingrecycledPETfibres.Thesecondpurposeofthisstudyistoapplydifferentalloca-tionmethodsforthisopen-loop-recyclingcase.InLCA,therehasbeensofarnostandardisedprocedureforopen-looprecycling.Sev-eralstudieshavediscussedthismethodologicalproblem(Ekvall,0921-3449/$–seefrontmatter©2010ElsevierB.V.Allrightsreserved.doi:10.1016/j.resconrec.2010.06.014L.Shenetal./Resources,ConservationandRecycling55(2010)34–5235Fig.1.ApplicationofrecycledPETflakes,worldwide2007,basedondatafromNoone(2008).Fig.2.Collectedpost-consumerwastePETbottlesinEuropeoverthelast10yearsbasedondatafromForum-PET(2009)andPetcore(2009b)andtheestimateforthenearfuturebasedon10%p.a.growthrate(Glenz,2007).VirginPETconsumptiondatawereobtainedfrom(Glenz,2004;PlasticsEurope,2009a).2000;EkvallandTillman,1997;Klöpffer,1996;WernerandRichter,2000).Acommonpracticeistofollowthe“cut-off”principlewhichdistinguishesthefirstlife(virginproduct)andthe