J. D. Cooney

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 mixed plastics used in the electronics industry

Abstract The pyrolysis of three plastics used by the electronics industry has been studied using pyrolysis/gas chromatography/mass spectrometry (Py/GC/MS). The materials selected for this study were acrylonitrile–butadiene–styrene (ABS), polycarbonate (PC) and polyoxymethylene (POM). The selection was based upon the analysis of several pieces of electronic equipment, which had been the subject of laboratory studies. Each polymer was pyrolyzed at two pyrolysis temperatures (700 and 900°C) alone, together (side by side) with polyvinyl chloride (PVC) in a 50/50 co-pyrolysis experiment, and as an intimate chemical blend with PVC (50/50). In addition the three polymers were also pyrolyzed in the presence of copper powder to determine the role of copper contamination on the pyrolysis of each polymer. The results of the study suggest that both the presence of PVC and copper can influence the extent of degradation and the pyrolysis product distribution obtained when these polymers are pyrolyzed. However, no significant changes were noted that could drastically influence the value of the pyrolysis products.

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

Abstract 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.

The thermal degradation of poly(aryl—ether—ether—ketone) (PEEK) as monitored by pyrolysis—GC/MS and TG/MS☆

Abstract The thermal degradation of poly(aryl—ether—ether—ketone) has been studied over a range of pyrolysis conditions using both a flash pyrolysis—gas chromatography/mass spectrometry technique (Py—GC/MS) and a thermogravimetry/mass spectrometry technique. The major volatile thermal decomposition product was found to be phenol, which dominated all other volatile species especially under the least severe pyrolysis conditions. Under more severe pyrolysis conditions, such as those encountered in the Py—GC/MS experiments, a much wider range of volatile products was obtained. The results have been interpreted to imply that the primary random chain scission reactions occur at the ether linkages and it is only under more severe pyrolysis conditions that random chain scission also involves the ketone linkage.

Thermal Analysis of Some Environmentally Degradable Polymers

The thermal characteristics of a series of degradable polymers have been investigated using thermogravimetry and differential scanning calorimetry. While the results of the thermogravimetry experiments suggest that the thermal stability of the polymers should not pose any problems at the temperatures that can be expected in a commercial composting process (60°C), phase changes associated with some of the polymers investigated may cause problems in the interpretation of data from composting degradation studies. Several biodegradable polymers were observed to have melt transitions at temperatures similar to those found in a composting environment. Consequently, under the controlled composting conditions used to evaluate biodegradable polymers, degradation of a polymer may be inferred, while actually the polymer has merely undergone a phase change.

The kinetics of the oxidattve degradation of poly(aryl-ether-ether-ketone) (PEEK)

Abstract The kinetic parameters of the thermal decomposition of poly(aryl-ether-ether-ketone) (PEEK) in air have been investigated using an isothermal weight-loss method. The results from these studies indicate that the decomposition process is a complex one which proceeds in several overlapping stages. Calculation of the kinetic parameters by a variety of models suggests that at the lower isothermal temperatures the initial weight-loss process occurs with an apparent activation energy of about 100 kJ mol −1 . At higher isothermal temperatures, however, the rates appear to be controlled by diffusion factors and higher apparent activation energies are noted of around 185 kJ mol −1 for the earlier weight-loss fractions and of about 220 kJ mol −1 for the later weight-loss data. The analyses presented demonstrate the difficulties which can arise in determining meaningful mechanistic information from standard weight-loss data even when isothermal heating conditions are employed.

Degradation behaviour of polymeric materials found in auto Shredder residue wastes

The thermogravimetry of a series of 50/50 mixtures of polypropylene, acrylonitrile/butadiene/styrene, polyvinyl chloride and polyurethane polymers have been studied as representative of the major polymeric materials found in automobile shredder residues. The weight loss behaviour of these polymeric mixes have been compared with the results calculated from the individual polymeric components. This comparison of the thermogravimetry curves and the calculated kinetic parameters indicates that interactions occur between the individual polymers when heated together. The extent of these interactions are dependent upon the polymeric mixtures being considered, but in most cases the changes in the degradation kinetic parameters were not large.ZusammenfassungEine Reihe von 50/50-Gemenge aus Polypropylen, Acrylnitril/Butadien/Styrol, PVC und Polyurethanpolymeren als typische Vertreter von Automobil-Häckselresten wurden thermogravimetrisch untersucht. Das Gewichtsverlustverhalten dieser Polymergemenge wurde mit den für die reinen Polymerkomponenten errechneten Resultaten verglichen. Dieser Vergleich von TG-Kurven und errechneten kinetischen Parametern zeigt, daß beim Erhitzen der Gemenge Wechselwirkungen zwischen den einzelnen Polymerkomponenten auftreten. Das Ausmaß dieser Wechselwirkungen hängt von der Zusammensetzung der Gemenge ab, jedoch sind die Änderungen der kinetischen Parameter für die Zersetzung in den meisten Fällen nicht groß.

The use of thermogravimetry to analyze a mixed plastic waste stream

The thermogravimetry of a mixed polymer waste stream has been studied and the weight-loss behaviour of this heterogeneous mixture has been compared with results obtained from the weight-loss curves of some individual polymers. The results suggest that the behaviour of the mixture cannot be predicted by the simple additive behaviour of the individual polymers since interactions can occur which influence the degradation weight-loss profiles. The heterogeneous polymeric waste studied was that generated from the shredding of old discarded automobiles. The results of the study indicate that while it is possible to determine what is present in a sample, the relevance of the data to a very heterogeneous waste stream is questionable.ZusammenfassungDie Thermogravimetrie gemischter Polymerabfallströme wurde untersucht und das Gewichtsverlustverhalten dieser heterogenen Gemische mit den Resultaten der Gewichtsverlustkurven einiger reiner Polymere verglichen. Die Ergebnisse weisen darauf hin, daß das Verhalten des Gemisches nicht anhand eines einfachen additiven Verhaltens der Polymerkomponenten vorausgesagt werden kann, da Wechselwirkungen auftreten können, welche die Gewichtsverlustporofile der Zersetzungen beeinflussen. Der untersuchte heterogene Polymerabfall wurde durch Zerkleinerung von alten ausrangierten Automobilen gewonnen. Die Resultate der Untersuchung zeigen, daß es möglich ist, zu bestimmen, was in einer Probe enthalten ist, daß jedoch die Relevanz der Daten bei einem sehr heterogenen Abfallstrom fraglich ist.

A kinetic study of the thermal degradation of polyester/cotton blends by thermogravimetry

Abstract The weight loss curves obtained from a series of polyester/cotton blends heated in air at heating rates of 0.1–5°C min −1 have been determined and compared with those calculated from the individual components. Comparison of the thermogravimetric curves and calculated kinetic parameters indicates that interactions occur between the polyester and cotton components in the blends. Although these interactions may be primarily physical in nature, they are sufficiently large to cause changes in the degradation kinetics of the weight loss processes responsible for gaseous product formation.

The use of thermal analysis to study thermal processing effects on polypropylene

The thermal stability of a polypropylene copolymer has been examined at several stages during the processing of the material into its final product in order to obtain information on the influence of processing steps such as grinding and thermal heating on the expected lifetime of the material. Mass loss kinetics in an inert atmosphere were able to detect differences in thermal stability, but oxidative differential scanning calorimetry studies proved to be a more sensitive techiique. A comparative study of a specially prepared series of samples revealed the importance of additives on measured thermal stability and indicated that both mechanical and thermal processing can cause reduction in measured thermal stability.ZusammenfassungBei verschiedenen Schritten der Verarbeitung von Polypropylen-Kopolymer zum Endprodukt wurde die thermische Stabilität untersucht, um Informationen über den Einfluß von Verarbeitungsschritten, wie z.B. von Mahlen und Erhitzen auf die voraussichtliche Lebensdauer des Materiales zu erhalten. Mit, Hilfe der Gewichts- verlust-Kinetik in inerter Atmosphäre können Unterschiede, in der thermischen Stabilität nachgewiesen werden, jedoch erwiesen sich oxidative Scanningkalorimetrie-Untersuchungen als empfindlicher. Die Vergleichsstudie einer speziell. hergestellten Serie von Proben erwies den Einfluß von Additiven auf die thermische Stabilität und zeigte, daß sowohl die mechanische als auch die thermische Bearbeitung ein Absinken der thermischen Stabilität verursachen kann.