Pyrolysis of auto shredder residue: experiments with a laboratory screw kiln reactor

Abstract

The pyrolysis of automobile shredder residue (ASR) has been studied using a laboratory scale screw kiln reactor with a feed rate of about 100 g h − 1. Pyrolysis at temperatures between 500 and 750°C resulted in the production of gas, liquid and solid fractions with hydrocarbon yields of the organic fraction present in the feed increasing from 60 -85% with increasing pyrolysis temperature. While the hydrocarbon pyrolysis product yield increased with pyrolysis temperature, the yield of the oil fraction was higher at the lower pyrolysis temperatures. The composition of the pyrolysis oil also changed with pyrolysis temperature, containing larger quantities of aliphatic compounds at the lower temperatures than at higher temperatures where aromatics were the major compounds. Many of the liquid pyrolysis products have been identified including polycyclic aromatic hydrocarbons as well as organo nitrogen, sulphur and chlorine compounds. The data obtained have been compared with that obtained from a process using short pyrolysis residence times.

Challenges and Alternatives to Plastics Recycling in the Automotive Sector

“… reuse of SR as landfill day cover [50][51][52];  reuse of SR as a hydroponic garden growing medium [53];  use of the organic portion of SR as an alternative fuel source or reducing agent in blast furnaces [50,54,55];  use of SR as an alternative fuel and mineral feedstock for cement production [55,56];  recycling of SR in the manufacture of composite plastic building products, e.g., plastic lumber [57,58];  pyrolysis of SR to produce a synthetic coal/fuel product [51,55,[59][60][61][62]; and  recycling of SR plastics, involving the conversion of the plastics into low molecular weight hydrocarbons (such as via low-temperature, catalytic conversion) for reuse as chemicals or fuels [55,62,63].…”

Hydrogen from waste plastics by way of pyrolysis–gasification

“…However, for the development of an industrial scale process, a continuous reactor system would be required to ensure commerciality. Among various reactors for the thermal processing of waste plastics, the continuous screw kiln has been proposed to be a preferred reaction system for industrial commercialization (Aguado et al, 2002, Day et al, 1999, Serrano et al, 2003. Furthermore, it has been suggested that the screw kiln reaction system might reduce the over-cracking of plastics, and generate a comparatively narrow range of products that could be reformed in a second stage to produce hydrogen gas (Czernik and French, 2006).…”

Characterisation of rotary kiln residues from the pyrolysis of shredder residues: Issues with lead

“…The remaining materials include foam, textiles, carpet, rubber, plastics, paint, wood and glass [3,[5][6][7] and are known collectively as automotive shredder residue (ASR). Commonly, shredder facilities process both ELVs and other feedstock (e.g white goods, light iron) together and the resultant waste stream is terms shredder residue (SR).…”

“…However, it also contains metal pieces of varying sizes, which makes this very difficult for an analytical laboratory to process. Other studies have reported some metal levels [5,11,12]; they already show metals such as lead to be present at levels of some concern, and raise the question of whether new de-pollution techniques for ELVs can significantly reduce those levels.…”

“…Many studies and processes have been published which report on potential pyrolysis of ASR, usually with a focus on producing useful gases or liquids such as diesels or oils [2,3,5,6,10,11]. Fewer have focused on the production of a char or ash suitable for use as a raw material [5,11,12] -though some have looked at ways of using it as a replacement fuel for fossil fuels [13]. However, despite this work, ASR is still not pyrolysed on a commercial scale, and this paper concentrates on one very significant barrier; the presence of heavy metals in the char which prevents it being used as a recycled material.…”