Session: Transport

An Assessment of Mechanical and Thermal Conversion Technologies Used in the Recycling of Shredder Residue based on A Life Cycle Approach
Dr. Candace S. Wheeler,   General Motors/Vehicle Recycling Partnership
Nakia L. Simon,^*   DaimlerChrysler/Vehicle Recycling Partnership
Dr. Claudia M. Duranceau,   Ford/Vehicle Recycling Partnership

A number of new technologies are currently under investigation by the Vehicle Recycling Partnership (VRP) and its partners, which are designed to substantially enhance the recycling of end-of-life vehicles and, in particular, the residue, which remains after the vehicles are shredded, and the metals recovered. These technologies fall primarily in one of two types. They include mechanical separations processes, which are designed to recover materials of value from the shredder residue stream, or thermal conversion technologies designed to convert hydrocarbons and other organic materials into marketable oils and specialty chemicals for potential industrial and commercial use. In this study, we looked at the relative environmental benefits/impacts associated with both of these recycling strategies using a life cycle approach. We found that the thermal conversion technology showed an overall environmental benefit for all considered environmental issues compared to the mechanical recycling process. However, the results were highly dependent on the use of the produced product streams. To increase the benefits of the mechanically recovered fractions, the purity of the recovered fractions would have to be increased enabling the materials to be used in higher value applications. Also,the direct solvent emissions were critical with the greatest share of the output emissions related to the contamination of the residue with diesel and gasoline. Additional research is underway to improvement the environmental performance of both processes.

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