Pretreatment of Automotive Shredder Residues, Their Chemical Characterisation, and Pyrolysis Kinetics

Sandhya Kuruvalan Vijayan,Sankar Bhattacharya,Md Hemayet Uddin,Mahmud Arman Kibria

doi:10.3390/su131910549

Abstract

Automotive Shredder Residue (ASR), a waste when metals are mostly removed from end-of-life vehicles, has constituents similar to municipal solid waste (MSW) consisting of plastics, rubber, textiles, and some metals. The processing of ASR is a challenge due to its heterogeneous nature, making feeding to a reactor difficult. In this work, a new procedure of ASR pretreatment is proposed to bring particulate nature in the sample for easier feeding during pyrolysis. The thermal breakdown characteristics of the pretreated ASR solids under slow pyrolysis conditions were assessed in a thermogravimetric analyser following the International Confederation for Thermal Analysis and Calorimetry (ICTAC) kinetics committee recommendations. The effect of particle sizes and heating rates were studied at temperatures up to 800 °C at different heating rates of 2, 5, and 10 °C/min for three particle sizes, 38–63 µm, 63–90 µm, and 90–106 µm, and the kinetic data were derived. The volatiles emitted during pyrolysis were characterized by Diffuse Reflectance Infrared Spectroscopy (DRIFTS). We also developed an algorithm for the selection of heating rate during the pyrolysis of the pretreated ASR. The DRIFTS results, kinetic data, and heating rate for the selected particle sizes are useful for the development of a pyrolysis process for pretreated ASR.

Highlights

There are about 50 million units of end-of-life vehicles (ELV) per year which generate50 million tonnes of waste annually worldwide [1]
We report the physicochemical characterisation of the pretreated Automotive Shredder Residue (ASR) material through X-ray Diffraction (XRD), electron microscopy (SEM), X-Ray Fluorescence (XRF), and Diffuse Reflectance
The volatile matter remains mostly unaltered after the ASR pretreatment and is found to be in the same range from 54–74% as reported in the literature [24,25,26]

Summary

Introduction

There are about 50 million units of end-of-life vehicles (ELV) per year which generate. 50 million tonnes of waste annually worldwide [1]. In recycling ELVs, there are three phases in ELV pre-processing, namely de-pollution, dismantling, and shredding. In the depollution and dismantling stages, the engine and tires are removed, followed by the removal of batteries, fluid, and fuel. The final car hulk, which constitutes 60% of the weight, is shredded in a shredding unit. The shredded materials are taken to magnetic separators for the segregation of ferro-metals. The ferrous fraction represents approximately 70–75% of the total shredded output, while non-ferrous metals represent about 5%. The remaining 20–25% fraction is referred to as automotive shredder residue (ASR)

Methods

Results

Conclusion