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Most studies on the properties and recycling of automotive shredder residue (ASR) have been carried out without fully understanding the composition of the input scrap. Equally important is understanding the type of shredding process, and types of processes utilized for separation of ferrous and non-ferrous metals from the shredded material. The Vehicle Recycling Partnership (VRP) has been conducting a project:“Study of Plastic Material Recovery From Automotive Shredder Residue” [1]. One of the objectives of this VRP project is to determine the relationship between the shredder input and ASR properties. A 1995 Dodge Stratus was dismantled in detail to obtain information necessary for the project, such as material usage in the vehicle [2]. Then, under tightly controlled conditions, 14 late model Chrysler Cirrus and Dodge Stratus automobiles were shredded and processed.

The United States Field Trial was chartered by the United States Council for Automotive Research/Vehicle Recycling Partnership (USCAR/VRP) with the objective of evaluating the feasibility and viability of collecting and recycling automotive polymers from domestic End-of-Life Vehicles (ELVs). European concerns regarding vehicle abandonment risks, decreasing landfill capacity, and disposal practices have resulted in the legislated treatment of ELVs in Western Europe. The emergence of attendant material collection schemes promoting material recycling may not apply to the free-market economic conditions prevalent in North America vehicle recycling infrastructure. Although ELVs are among the most widely recycled consumer products, 15-25% of their total mass is currently discarded with no material recovery, although their residue, when permitted, is a preferred landfill day cover in some areas.

Approximately 20 percent by weight of each end of life automobile ends up in a waste stream known as shredder residue (SR) that goes to disposal into a land fill. When an automobile reaches the end of its useful life it enters a complex infrastructure designed to recover usable parts and materials of value, primarily the ferrous and non-ferrous metals. The remaining material, a mixture of glass, rubber, plastics and foam becomes part of SR. Based on earlier research, a new recycling process has been identified that can convert the organic material in this waste stream into a fuel oil. The Thermal Conversion Process (TCP) developed by Changing World Technologies (CWT) may make it possible to convert SR into useful products. The Vehicle Recycling Partnership (VRP) and its partners are investigating the capability of the TCP to process SR.

Polyurethane (PU) foams were recovered from European and U.S. shredder residues, which typically come from automobiles and other sources of durable goods, such as appliances, furniture, construction, etc. PU foams were characterized and glycolyzed. Glycolysis products were successfully treated for the removal of select substances of concern, heavy metals, and bromine-containing compounds and propoxylated into polyols for polyurethanes with 171 and 355 average equivalent weights. Properties of the glycolysis product and corresponding propoxylated polyols were evaluated, including their molecular weight distribution via gel permeation chromatography (GPC). The polydispersity index decreased from 5.8 to 2.1 by reaction of glycolysis product with 50 wt% of propylene oxide based on a total amount of the initiator. The recycled polyol of an average equivalent weight of 171 was evaluated in rigid polyurethane and urethane-modified isocyanurate foam formulations.

Each year approximately 12 million automobiles reach the end of their useful life and enter a complex infrastructure designed to recover usable parts and materials of value (primarily the ferrous and nonferrous metals). The remaining material, a mixture of glass, rubber, plastics, foam, and dirt, is referred to as shredder residue (SR) and is currently sent to landfills for disposal. However, a new Thermal Conversion Process (TCP) developed by Changing World Technologies may make it possible to convert this waste into a light hydrocarbon oil. TCP is a new technology under investigation by the Vehicle Recycling Partnership (VRP) and its partners. This process converts hydrocarbons and other organic materials into marketable oils and specialty chemicals for potential industrial and commercial use. Early research has demonstrated the ability to take SR and convert it into a light hydrocarbon oil, fuel gas, and carbon.

In previous projects, the Vehicle Recycling Partnership (VRP) and Salyp N.V. have demonstrated the ability to separate plastics, foams, ferrous metals, and non-ferrous metals from shredder residue using the Salyp recovery process. Salyp's recovery process consists of a number of different stages, which are discussed in a previous SAE paper by the VRP and Salyp1. These include a sized-based material separation, a foam cleaning system, additional material separation based on material type, etc. However, during the previous project, the potential impact of the process on the environment via air emissions, waste emissions, or in terms of energy consumption were not determined. Understanding the overall environmental impact of this recycling process is important. Therefore, the VRP concluded that a life cycle approach was necessary to investigate the energy and specific environmental impacts of this technology.