Studies on gasification and melting characteristics of automobile shredder residue

The present technology to handle end-of-life vehicles usually generates about 20-30% of the automobile shredder residue (ASR) of a new car in weight, which is disposed of via landfill or combustion at cement kilns and incinerators. Recently, surveys to compare various techniques such as pyrolysis, gasification, and melting to treat ASR with a better recycling rate have been reported. Gasification and melting processes are operated at high temperatures with the destruction of hazardous components and production of gases, mainly CO and H₂, which can be utilized as fuel gas or raw chemicals after cleaning. Also the remaining slag solid portion is stable enough without being hazardous and it can be utilized as recycled material. In this study, ASR sampled from a shredding company was tested in a laboratory-scale gasification and melting process to characterize the gaseous and slag products. At higher temperatures and a lower air equivalent ratio (ER), CO, H₂, and CH₄ emission increased but CO₂ and N₂ decreased. C₂H₆ concentrations changed, but different ERs were not clear. However, there was an increasing tendency of its emission amount at lower temperatures. Carbon conversion efficiency, gas yield (Gy), and CO₂ increased with an increasing ER. Thus, when the temperature was higher, Gy and carbon conversion efficiency increased. By-product yield was related to carbon conversion efficiency and Gy. Characteristics of slag produced, such as segregation of metal, leaching property, composition, and surface morphology, were also analyzed.