Catalytic Conversion of Automobile Shredder Residue to High Energy Fuels

Catalytic pyrolysis of automobile shredder residue to high energy fuels

FA Agblevor, K. Christian, S. Hatch, J. Long

USTAR Bioenergy Center, Biological Engineering, Utah State University, Logan UT 84322

Abstract

Automobile shredder residue (ASR) or auto-fluff is waste product from the extraction of metals from automobiles.  The material is composed of plastics, vinyl, cellulose, wood, metals, leather, and other materials.  ASR is currently disposed in public landfills.  However because of the organic material content of this residue, it is potentially possible to convert the material to fuels using pyrolysis technology.  ASR and red mud samples were characterized using several methods.  The ASR samples showed large variability and had very high ash content.  The ASR samples were pyrolyzed using sand and red mud.  Pyrolysis oils obtained using sand as the pyrolysis medium were more viscous than those using red mud and they also contained polychlorinated biphenyls (PCB) at high levels.  The yield of ASR pyrolysis liquids ranged from 2 to 32 wt%.  Pyrolysis with red mud produced much lower viscosity oils and which also had very low PCB content.  Whereas there were several types of PCBs in the sand pyrolysis oils, there was only one type PCB congener (trichlorobiphenyl) in the red mud ASR pyrolysis oils.  Modification of the red mud with reduced the PCB content of the ASR red mud pyrolysis oils to 5 ppm compared to over 50 ppm in the sand ASR pyrolysis oils. The red mud ASR pyrolysis oils had close to neutral pH while the sand pyrolysis oils were acidic.  The gas yield ranged from28 to 36 wt%.  The red ASR pyrolysis gas was H2-rich while the sand catalyzed pyrolysis oil was CO2-rich.  The char-yield was very high and ranged from 38 to 42 wt% and had ash content over 70%.  The red mud ASR pyrolysis oil in its current state can be potentially used as heating fuel but needs upgrading to qualify as transportation fuel.