Thermal and catalytic pyrolysis of a mixture of plastics from small waste electrical and electronic equipment (WEEE)

Chiara Santella, Lorenzo Cafiero, Doina De Angelis, Floriana La Marca, Riccardo Tuffi, Stefano Vecchio Ciprioti

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24 Citations (Scopus)

Abstract

Pyrolysis seems a promising route for recycling of heterogeneous, contaminated and additives containing plastics from waste electrical and electronic equipment (WEEE). This study deals with the thermal and catalytic pyrolysis of a synthetic mixture containing real waste plastics, representative of polymers contained in small WEEE. Two zeolite-based catalysts were used at 400 °C: HUSY and HZSM-5 with a high silica content, while three different temperatures were adopted for the thermal cracking: 400, 600 and 800 °C. The mass balance showed that the oil produced by pyrolysis is always the main product regardless the process conditions selected, with yields ranging from 83% to 93%. A higher yield was obtained when pyrolysis was carried out with HZSM-5 at 400 °C and without catalysts, but at 600 and 800 °C. Formation of a significant amount of solid residue (about 13%) is observed using HUSY. The oily liquid product of pyrolysis, analysed by GC-MS and GC-FID, as well as by elemental analysis and for energy content, appeared lighter, less viscous and with a higher concentration of monoaromatics under catalytic condition, if compared to the liquid product derived from thermal degradation at the same temperature. HZSM-5 led to the production of a high yield of styrene (17.5%), while HUSY favoured the formation of ethylbenzene (15%). Energy released by combustion of the oil was around 39 MJ/kg, thus suggesting the possibility to exploit it as a fuel, if the recovery of chemical compounds could not be realised. Elemental and proximate analysis of char and GC-TCD analysis of the gas were also performed. Finally, it was estimated to what extent these two products, showing a relevant ability to release energy, could fulfil the energy demand requested in pyrolysis.
Original languageEnglish
Pages (from-to)143 - 152
Number of pages10
JournalWaste Management
Volume54
DOIs
Publication statusPublished - 1 Aug 2016
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Waste Management and Disposal

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