Influence of pre-screening on down-stream processing for the production of plastic enriched fractions for recycling from mixed commercial and municipal waste. (1st January 2021)

• Record Type: Journal Article
• Authors: Möllnitz, S.; Küppers, B.; Curtis, A.; Khodier, K.; Sarc, R.
• Is Part Of: Waste management. Volume 119(2021)
• Page Start: 365
• Page End: 373
• Publication Date: 2021-01-01
• Subjects: Mixed commercial waste -- Mixed municipal waste -- Drum screening -- Circular economy -- Polymer recycling -- 2D- & 3D-plastics -- Sensor-based sorting; ηB screening efficiency of the ballistic separator -- ηS screening efficiency of the drum screen -- ηtotal overall screening efficiency -- 2D two-dimensional -- 3D three-dimensional -- approx. approximately -- B_ ballistic seperation without screening -- DM dry mass -- DMFMS Digital Material Flow Monitoring System -- e.g. for example -- EU Europe -- FF2D fine fraction of the 2D-fraction -- FF3D fine fraction of the 3D-fraction -- FFB fine fraction of the ballistic separator -- FFS fine fraction of the drum screen -- FFtotal total fines content -- kJ kilo joules -- M mass -- max maximum -- m2 square meters -- m3 cubic metres -- MCW mixed commercial solid waste -- mm millimetres -- MMW mixed municipal solid waste -- MSW mixed solid waste -- mtotal total imput mass -- ṁtotal throughput rate -- NIR Near Infrared -- OS original substance -- P purity -- P&C paper and cardboard -- PE-LD polyethylene low density -- PE-HD polyethylene high density -- PP polypropylene -- PET polyethylene terephthalate -- PS polystyrene -- PU polyurethan -- PVC polyvenyl chloride -- rpm revolutions per minute -- S+B_ screening and ballistic seperation -- SBS sensor-based sorting -- SRF solid recovered fuel -- V̇ volume flow -- V1/V2 test run number 1/2 -- wt.-% percentage by weight -- Y yield; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2020.10.007
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Influence of pre-screening on down-stream processing is investigated. Pre-screening improves the quality of the output. Drum sieving cleans the surface of objects and hence increases sorting yields. Selective size reduction enhances the enrichment of valuable materials. Proper pre-treatment can raise the sorting yield by 3–5%. Abstract: The use of plastic waste as resource gains more and more attention. In this context, material recycling is especially focused on packaging plastics. Further waste streams that contain a significant amount of plastics are mixed commercial and municipal solid waste. To assess the potential of plastics for recycling and energy recovery from these material streams large-scale experiments were conducted. The potential of mechanical pre-processing with the aim of generating a 3D-plastics pre-concentrate was assessed. The focus of these investigations was put on the relevance of the screening stage and its influence on down-stream material processing via ballistic separation and sensor-based sorting. Results demonstrate not only that the screening of both waste streams leads to enrichment of plastics in coarse particle size ranges (especially >80 mm) and transfer of contaminants, organics and minerals to fine fractions (especially <10 mm), but also that sensor-based sorting performance can be significantly enhanced due to cleaning effects on plastics, induced by the material circulation and the resulting interparticle friction in a drum screen. On the downside, the material rotation in a drum screen leads to tail-formation that can create plant down-time through clogging as well as material losses and impairment of pre-concentrates.