Characterization of a solid recovered fuel for prediction of its thermal degradation

Abstract

The objective is to characterize one solid recovered fuel (SRF) and to determine a mixture of model components to represent each of its fractions, both in terms of elemental composition and thermal degradation kinetics. The SRF was first sorted into fractions: hard plastic (21%, mass fraction), soft plastic (12%), wood (15%), paper and cardboard (13%), textile (11%), elastomer (6%), foam (4%), expanded polystyrene (PS, 3%), inert (6%) and fine particles (9%). The SRF fractions and selected model components were characterized in detail via thermogravimetric analysis (TGA), Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). The results confirmed the relevance or presence of a list of model components for each fraction. In the second step, the mass fractions of the model components in the mixtures were calculated for each SRF fraction, with a mathematical optimization method based only on the elemental analysis results. These mixtures succeeded in representing the compositions of the fractions, both for organic and inorganic elements. The hard plastic fraction mainly contains polyethylene (PE) and polypropylene (PP) at 38.6% each, as do PS (5.0%) and polyvinylchloride (PVC, 10.9%). The soft plastic fraction is well represented by PE. The textile fraction is complex and includes cotton (15.0%), polyethylene terephthalate (PET, 40.5%), PP (20.9%), and acrylic (5.2%). The fine particle fraction is rich in pollutants: soil (29.8%), plaster (20.3%), and glass wool (5.0%). The consideration of these fine particles in the SRF composition is thus crucial for determining the sources of inorganic elements.

Graphical abstract