A novel pathway to recover Hydrocarbons from polyethylene residues through self-sustaining smoldering combustion

Resumo: This study provides a detailed chemical and thermochemical characterizations of virgin and recycled Low-Density Polyethylene (LDPE), the major plastics present in the municipal solid waste. Following a careful methodology, the chemical composition was determined through ultimate, non-standard proximate and X-Ray diffraction analysis. The thermal degradation behaviour was analysed by TG-DTA. On average, the virgin and recycled polyethylene are composed mainly of carbon and hydrogen resulting in volatile material, 99.3 wt.\%, and ash, 0.5 wt.\%. The main molecules constituting the samples were Pentatriacontane, n-Paraffin, n-Tetracontane and n-Nonacosane. TG-DTA under inert atmosphere indicated that almost all mass is converted in a single step and two endothermic peaks were observed, one related to the melting and another to the polyethylene degradation. In the oxidative atmosphere, two main mass losses were observed representing around 94.5 wt.\% of the total mass oxidized. The Arrhenius parameters for the chemical reactions identified were estimated. Parallel reactions mechanisms were proposed for pyrolysis and combustion. The results show that a simplified mechanism is enough to describe the pyrolysis of the polyethylene in two steps. The detailed parallel mechanisms were formulated including intermediate species. The influence of the recycling process shows a slight influence on temperature range and kinetic parameters. However a sensible influence on the chemical composition and enthalpy of reaction.

Data de início: 01/05/2017
Prazo (meses): 24

Participantes:

Papel	Nome
Coordenador	MARCIO FERREIRA MARTINS