Visual-Acoustic Sensor-Aided Sorting Efficiency Optimization of Automotive Shredder Polymer Residues Using Circularity Determination.

Jiu Huang,Zhuangzhuang Zhu,Chaorong Xu,Longfei Xing

doi:10.3390/s19020284

Abstract

To reduce the emissions and weight of vehicles, manufacturers are incorporating polymer materials into vehicles, and this has increased the difficulty in recycling End-of-Life vehicles (ELVs). About 25–30% (mass) of an ELV crushed mixture is the unrecyclable material known as automotive shredder residues (ASRs), and most of the vehicle polymers are concentrated in this fraction. Thus, these vehicle polymers are conventionally disposed of in landfills at a high risk to the environment. The only way to solve this problem is through the development of a novel separation and recycling mechanism for ASRs. Our previous research reported a novel sensor-aided single-scrap-oriented sorting method that uses laser-triangulation imaging combined with impact acoustic frequency recognition for sorting crushed ASR plastics, and we proved its feasibility. However, the sorting efficiencies were still limited, since, in previous studies, the method used for scrap size determination was mechanical sieving, resulting in many deviations. In this paper, a new method based on three-dimensional (3D) imaging and circularity analysis is proposed to determine the equivalent particle size with much greater accuracy by avoiding the issues that are presented by the irregularity of crushed scraps. In this research, two kinds of commonly used vehicle plastics, acrylonitrile-butadiene-styrene (ABS) and polypropylene (PP), and their corresponding composite materials, acrylonitrile-butadiene-styrene/polycarbonate (ABS/PC) and polypropylene/ethylene-propylene-diene-monomer (PP/EPDM), were studied. When compared with our previous study, with this new method, the sorting efficiency increased, with PP and PP/EPDM and ABS and ABS/PC achieving about 15% and 20% and 70% and 90%, respectively. The sorting efficiency of ASR polymer scraps can be optimized significantly by using sensor-aided 3D image measurement and circularity analysis.

Highlights

With the rapid development of the global vehicle industry, both the worldwide production and ownership of automobiles have increased steadily over the last 20 years, making the automotive industry one of the biggest in the world [1,2]
This can lead to a leakage effect of the impact frequency response since, with the mean roundness method, not all vibrating parts on the tested scraps are included in their equivalent circularities
An RRSB distribution analysis was used to analyze the overall regularity of the tested scrap mixtures

Summary

Introduction

With the rapid development of the global vehicle industry, both the worldwide production and ownership of automobiles have increased steadily over the last 20 years, making the automotive industry one of the biggest in the world [1,2]. In China, for example, vehicle production and sales both reached 28 million in 2016 [3] and car ownership is expected to increase to 280 million by [4]. At the same time, the automobile industry is facing numerous challenges, such as energy consumption, greenhouse gas emission, and, waste disposal of End-of-Life vehicles (ELVs) [5]. As opposed to polymers, metals can be recycled conveniently. The use of polymers in automobile manufacturing has created many difficulties for ELV recycling

Methods

Results

Conclusion