Automobile Shredder Residue Pyrolysis Research Articles

Study on the pyrolysis characteristics and char gasification kinetics of pre-separated automobile shredder residues

Automobile shredder residue (ASR) is a typical solid waste produced by the end-of-life automobile industry. The pyrolysis and gasification of ASR are effective methods to achieve reduction and resource utilization. By means of thermogravimetric analysis and fixed-bed experiments, the distribution as well as physicochemical properties of five typical ASR pyrolysis products after pre-sorting were systematically investigated, and the gasification kinetics of their pyrolysis char under CO2 as well as steam were also studied. Results showed that the pyrolysis of ASR was basically completed at 500°C, and the pyrolysis gas yield increased significantly with temperature. The tar contained mainly poly-benzene rings with carbon atoms C11–15 and their derivatives. At high temperatures, the structure of pyrolysis char tended to become more ordered, with small functional group such as - OH, - NH, - CH3, - CC -, and - COOH fracturing. The residual amounts of heavy metals such as Cr, Pb, and Ni in pyrolysis char were mostly exceed 45%, which were significantly affected by the type of heavy metals, pyrolysis temperature and material type. Hydrogen production from steam gasification accounted for up to 65%, and the gasification reactivity was better than that of CO2 gasification. The activation energy (E) calculated through shrinking core model (SCM) and random pore model (RPM) was 38.81–105.44 kJ/mol and 39.53–98.56 kJ/mol, respectively, which provided a good fit to the gasification kinetics in two gasification atmospheres. This study provides detailed data for the ASR pyrolysis and gasification technology, which is an important reference value for ASR research.

Evolution and speciation transformation of chlorine during automobile shredder residue pyrolysis

Disposal of automobile shredder residue (ASR) via pyrolysis enables the recovery of valuable products; however, the production of hazardous pollutants and low-value products is inevitable due to its high chlorine content. In this work, chlorine evolution behavior and the conversion mechanism during ASR pyrolysis between 480 and 600 °C were systematically studied. The experimental results for organic chlorine (Org-Cl) showed that released chlorinated gases were complex, and HCl only accounted for 35% of the gas phase products, while short-chain hydrocarbons with carbon atoms between two and four accounted for 52%. Chlorine was predominantly retained in the char, and Org-Cl was the primary contributor to the residual chlorine, accounting for over 50% of the char. The content of inorganic chlorine (InO-Cl) was low in the raw sample but significantly increased in the char. Through the distinction between organic and inorganic chlorine content in char, it was confirmed that Org-Cl could be converted to InO-Cl due to complex secondary reactions with metallic compounds. The conversion was favored by increasing the Org-Cl content and the temperature. Our findings clarified the evolution mechanism of chlorine and the transformation from Org-Cl to InO-Cl, thus providing guidance for chlorine regulation and the efficient recycling of metal resources.

Enhancing pyrolysis of automobile shredder residue through torrefaction: Impact on heavy components formation in oil

Torrefaction of biomass is a well-known pretreatment method that can remarkably influence evolution of property of pyrolytic products in subsequent pyrolysis. Automobile shredder residue (ASR) is an important product in car recycling and it needs to be pretreated before recycling via pyrolysis. Nevertheless, how torrefaction impacts the composition and pyrolysis behaviours of ASR is still unknown, as ASR has a distinct composition from biomass. Thus, this study investigates the effect of torrefaction on the formation of heavy components in pyrolysis oil. ASR samples were torrefied from 240 °C to 330 °C and subsequently pyrolyzed from 600 °C to 800 °C with varied heating rates (ca. 80 °C /s and 0.17 °C /s). Results indicate that compared to raw ASR pyrolysis oil, torrefaction enhances the interaction between the volatile and semi-char, promoting the polymerization to form precursors of heavy components, thus the relative content of heavy components increases by >50% and heavy components containing heteroatoms decrease by >30% in the torrefied ASR pyrolysis oil, with the release of volatile heteroatom-containing compounds during torrefaction. More aliphatic heavy components are generated, reducing the overall aromaticity and degree of unsaturation of heavy components in the pyrolysis oil.

Influence of Interactions among Polymeric Components of Automobile Shredder Residue on the Pyrolysis Temperature and Characterization of Pyrolytic Products

Pyrolysis and gasification have gradually become the main means to dispose of automobile shredder residue (ASR), since these methods can reduce the volume and quality of landfill with lower cost and energy recovery can be conducted simultaneously. As the ASR pyrolysis process is integrated, the results of pyrolysis reactions of organic components and the interaction among polymeric components can be clarified by co-pyrolysis thermogravimetric experiments. The results show that the decomposition mechanisms of textiles and foam are markedly changed by plastic in the co-pyrolysis process, but the effect is not large for rubber and leather. This effect is mainly reflected in the pyrolysis temperature and pyrolysis rate. The pyrolytic trend and conversion curve shape of the studied ASR can be predicted by the main polymeric components with a parallel superposition model. The pyrolytic product yields and characterizations of gaseous products were analyzed in laboratory-scale non-isothermal pyrolysis experiments at finished temperatures of 500 °C, 600 °C, and 700 °C. The results prove that the yields of pyrolytic gas products are determined by the thermal decomposition of organic substances in the ASR and final temperature.

Pyrolysis of automobile shredder residue in a laboratory scale screw type reactor

Polymeric fraction of automobile shredder residue (ASR) was pyrolyzed in a laboratory scale screw type reactor under various conditions. All components of ASR and also a representative mixed sample of ASR were studied by thermogravimetric (TGA) analysis, differential scanning calorimetry (DSC), elemental analysis, bomb calorimetry and atomic emission spectrometry (AES). The ASR sample used in the laboratory pyrolysis apparatus contained mainly plastics, rubber, textiles, foam and other organics. The pyrolysis experiments were conducted at reactor temperatures ranging from 550 to 800°C, providing solid (30–34wt%), liquid (7–28wt%) and gas (42–65wt%) pyrolysis products. Composition of pyrolysis gases was measured online by a microchromatograph. By increasing the temperature, the content of hydrogen and CO in the gas fraction increased while that of light hydrocarbons decreased. The content of methane showed a maximum at 750°C. For pyrolysis char, its proximate and elemental composition, higher heating value and heavy metal content were determined. Char contained around 48wt% of fixed carbon; its sulfur content increased from 1.12wt% for char produced at 550°C to 2.31wt% for char produced at 800°C; its higher heating value varied between 14–19MJ/kg. Influence of the initial ASR composition was investigated as well. Increasing the content of rubber resulted in an increase of the char yield, while by increasing the plastic content, the gas yield increased. No significant effect of the ASR composition on the amount of liquid pyrolysis product was observed.

Research on ASR in China and its energy recycling with pyrolysis method

Automobile shredder residue (ASR) is the waste generated from recycling end-of-life vehicles. With the recent development of the automotive industry, proper ASR management is gaining significant attention because of the promotion of environmental awareness. Nonetheless, a systematic research on ASR is yet to be performed in China. In this paper, ASR is comprehensively studied using element analysis, combustion heat experiment, proximate analysis and thermogravimetric analysis (TGA). We investigated the feasibility of using pyrolysis to recycle and reuse ASR as a new energy source. Based on TGA experiments, ASR pyrolysis was analyzed with modified Kissinger method and Ozawa method, which optimize the pyrolysis and its industrial application. Finally, we established an ASR pyrolysis experiment platform, with which ASR pyrolysis experiments were conducted at 450 and 650 °C. The composition and content of the combustible gas produced during pyrolysis were measured.

Distribution and characteristics of pyrolysis products from automobile shredder residue using an experimental semi-batch reactor

Automobile shredder residue (ASR) generated by end-of-life vehicles, comprises more than 20% of a new vehicle by weight. Significant amounts of polymers in ASR, such as Poly Propylene (PP), Poly Ethylene (PE), Acrylonitrile Butadiene Styrene (ABS), Ethylene Propylene Ethylidene Nobomene (EPDM), rubber, Polyethylene Terephthalate (PET), Poly Amide (PA), and Poly Vinyl Chloride (PVC), can be used as energy or chemical sources, whereas other components, such as tires, rubber, glass, wood, sand/dust, and heavy metals inhibit the recycling of ASR. In many countries, landfill use of ASR is regulated, so landfill costs have increased, as has inappropriate disposal; sending ASR to landfills will be needed to be regulated in Korea. Pyrolysis has been suggested as an economically feasible recycling and recovery technique for ASR in Korea and other advanced countries. Before such technology is implemented, the characteristics of pyrolyzed products should be investigated. Shredded samples from the facility were collected, and calorific value, elemental analysis, and leaching tests were performed to determine ASR characteristics. Pyrolysis experiments were conducted at five different temperatures, 400, 500, 600, 700, and 800 °C, and the product distributions of gas, tar, and char were investigated. The optimal temperature for ASR pyrolysis, in terms of yield efficiency, was found to be 600 °C. The mean calorific value was also found to be higher in this case; thus, ASR can be treated as an auxiliary fuel. During pyrolysis, there were high ignition losses of light and heavy fluff, due to the presence of organic materials. The leaching concentrations of all tested heavy metals were found to be within the Korean guideline values. In terms of carbon number distributions, pyrolysis of ASR at 600 °C was optimal. For further utilization of pyrolysis products as fuel, the characteristics of char, oil, and gas were investigated with an experimental batch reactor.

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

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.

Pyrolysis of automobile shredder residue: an analysis of the products of a commercial screw kiln process

The products from the pyrolysis of automobile shredder residue, the waste produced in the recycling of old automobiles, have been studied. The pyrolysis process employed in the study was a commercial screw kiln unit. The chemical composition of the gas, liquid and solid fractions have been analyzed using a variety of techniques. The results of these analyses suggest that, while pyrolysis may represent a viable process for separating the organic materials from the inorganics, a full commercialization of the process must await a more detailed evaluation of the marketability of the products and their acceptance as feeds for full resource recovery.