Piero Frediani

By Piero Frediani and Marco Frediani

A single type of thermoplastic polymer is easily recycled through a mechanical process, but this way can’t be followed in the presence of mixed or contaminated plastic. In this case, one of the main followed solutions is a thermochemical process and among them, microwave-assisted pyrolysis is one of the emerging technologies. This chapter offers an update of the microwave-assisted pyrolysis of mixed or contaminated waste plastic as a very promising example of chemical recycling. Furthermore, some unpublished results in this field will be reported such as the pyrolysis of waste lead containing polyethylene coming from end cycle batteries or the pyrolysis of waste polypropylene from facemasks used for covid protection. Finally, some examples of pilot plants will be described and commented as well as several industrial cooperations.

Part of the book: Recent Perspectives in Pyrolysis Research

By Marco Frediani, Piero Frediani, Gianni Innocenti, Irene Mellone, Roberto Simoni and Gianpaolo Oteri

One of the great challenges for the European Union (EU) is the “Circular Economy Package,” and to achieve this goal, materials at the end of their life cycle must be recycled using a sustainable process. In this way, as a thermochemical treatment, pyrolysis represents a significant opportunity so long it leads to the recovery of both energy and chemical content of mixed, contaminated, or deteriorated plastics. An excellent history of an academic-industrial adventure started in 2008 at the Department of Chemistry of the University of Florence demonstrates the possibility of employing microwaves to recycle plastics to preserve their energy and chemical content. After that, Techwave started industrialization of the process in 2019, realizing a small-scale prototype followed by a full-scale pilot plant using different plastic materials (e.g., polystyrene, acrylonitrile-butadiene-styrene (ABS), and polypropylene). Nowadays, the plant may process 90 kg/h of plastics with a low formation of char and gas and an interesting amount of liquid useful as a source of chemicals or fuel because it has an LHV of 35–43 kJ/kg. The Microwave-Assisted Pyrolysis (MAP) is an industrial novelty in plastic recycling, and it looks very promising for a much more modern and innovative plastic waste recovery system.

Part of the book: Recent Microwave Technologies