Microwave Pyrolysis of Plastic Wastes

Department of Chemical Engineering, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA, UK 

Microwave pyrolysis of plastic (or plastic-containing) wastes is a relatively new area that has been studied only in the last decade or so. Because of this, there is considerably less information in the scientific literature compared with other approaches to the pyrolysis of plastics. Also, there is a substantial amount of information contained in patents, which suggests that the development of microwave pyrolytic processes has been more intuitive rather than strictly scientific. This chapter will summarize the developments in this area that are described both in scientific and commercial literature. 

The chapter begins by introducing the concepts behind microwave heating and the properties that make plastics transparent to this kind of radiation. This is followed by a definition of microwave pyrolysis of plastics and the ways that microwave transparency of plastics can be overcome in order to use this microwave energy as a source of heat for pyrolysis. A number of microwave pyrolytic processes for materials other than plastics are also introduced. 

The literature review of microwave-assisted or induced pyrolysis of plastics follows. In this section special attention is paid to the reactor configurations used, comparing them with the configurations found on more conventional pyrolysis equipment. The most important findings produced from this research are presented, including product yield, characteristics and composition. An analysis is presented to assess whether in any example there is evidence for nonthermal microwave effects promoting the pyrolytic reactions. 

The last section will focus on a review of the commercial literature, e.g. patents and companies websites. The aim of this section is to analyse the claims made in these documents in the light of the information present in the scientific studies. Flow diagrams, equipment characteristics and process results are analysed in a new exercise that shows 

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