MWCNTS Production by Means of Pyrolysis of Polyethylene-Terephtalate in a Bubbling Fluidized Bed

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A bubbling fluidized bed reactor having 102mmID and realised in AISI 316L stainless steel has been used as pyrolyser under different operating conditions. The reactor has been operated at fixed fluidising velocity (U=0.16m/s) and at 650°C and 800°C by feeding polyethylene-terephtalate as obtained by recycling of bottles. During several experiments the quantification of the yield and composition of gas (C1-C4 hydrocarbons, hydrogen, …) and liquids (e.g. high-boiling hydrocarbons generally defined tars) was made. The composition of pyrolysis gas has been obtained by using an Agilent micro GC 3000 that analysed the gas stream each 300s so allowing to have a quasi-continuous time profile of each gas component. Liquids were sampled by means of adsorption in a Tenax cartridge and analysed by means of thermal desorption in a GC-MS. The solid phase has been characterized by means of different methods: TG-DTG allowed to obtain a preliminary indication about the nature of the different compounds present in the solid sample by means of determination of their thermal stability in inert and oxidising environment; SEM and TEM microscopy, coupled with EDAX analysis, allowed to investigate the morphology of solid structures and to recognise the presence of some specific elements (e.g. metals included into the structures). Different nanostructures, having different degradation temperatures, have been obtained at 650°C and at 800°C. Moreover, the effect of metals extracted by reactor walls on MWCNTs production and the activation/deactivation of these “in-situ” catalyst during pyrolysis of PET is described and supported by experimental evidences.

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Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2008: Materials, Fabrication, Particles, and Characterization – Technical Proceedings of the 2008 NSTI Nanotechnology Conference and Trade Show, Volume 1
Published: June 1, 2008
Pages: 163 - 166
Industry sector: Advanced Materials & Manufacturing
Topics: Carbon Nano Structures & Devices
ISBN: 978-1-4200-8503-7