ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS

1. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS Matti Ranta-Korpi University of Jyväskylä

2. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS The global consumption of plastics was about 250 Mtons in 2008 The consumption of plastics will even increase in the future The problem of plastic solid waste (PSW) The use of plastic solid waste as raw material for SRF Energy recovery Volume reduction Problems in combustion Inorganic/organic additives used in plastics Their harmful effects to the boiler materials

3. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS OBJECTIVES FOR THE RESEARCH WORK • Alreadydone • Tworeviewpapers for the characterization of additivecompounds in plastics • The chemicalcomposition/formula of the additivecompounds • The typicalloadinglevels of additivecompounds • The evaluation of the elementalmetal/halogen/sulfurconcentration in plastics Results Table 1. Metals in plasticsTable 2. Halogens and sulfur in plastics

4. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS OBJECTIVES FOR THE RESEARCH WORK • Present work • The determination of metal concentrations in plastics • Wet/dry ashing of plastics • Dissolving of plastic materials by acids/combustion of organic part and dissolution of ash resulting from the combustion • Measurements by ICP-OES/EDXRF Table 3. Metal concentrations in plastics determined by ashing/ICP-OES

5. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS OBJECTIVES FOR THE RESEARCH WORK • Present work • The investigation of behavior of additive compounds during combustion • Goal: In what form the compounds inside the plastic matrix exist during the thermal treatment/when released to the combustion atmosphere Picture 1. Stages of combustion for a solid fuel particle (source: J. Konttinen)

6. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS Examplesfromexperimentalmethods and techniques • Thermaltreatment of plasticsbyTGA/electricfurnace/pyrolyzer • Adjustabletime and heatingprofile • The remainderafter the thermaltreatmentwillbeanalyzedbysuitablemethods Picture 2. TGA curve of LDPE plastic bag in air atmosphere

7. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS Examplesfromexperimentalmethods and techniques • Investigation of structuralchanges of additives • SEM-EDX analysis of plasticsamples • Picturesfromsamples and mapping of concentrations of elements in selectedarea • The possibility to investigate the formation of elementclusters Picture 3. The finestructure of PVC sample (2000X magnification) (a) (b) (c) Picture 4. The mapping of concentrations of elementsby SEM-EDX fromselectedarea. (a) oxygen, (b) aluminum and (c) silicon

8. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS Examplesfromexperimentalmethods and techniques • Investigation of structuralchanges of additives • Identification of additives in polymers by Raman spectroscopy and XRD • Characterization of structurechangesduring the combustion • Concentrationshigherthan 1 wt-% areneeded in order to detect the specificcompoundsin the plasticmatrix Picture 5. The Raman spectrum of certified HDPE reference material containing several different metal compounds

9. ASH FORMING ELEMENTS IN PLASTICS –THERMOCHEMICAL CONVERSION OF ADDITIVE COMPOUNDS ACKNOWLEDGEMENTS Metso Power Oy Foster Wheeler Energia Oy EuropeanRegionalDevelopmentFund RegionalCouncil of Central Finland