Engineering

Char

Pyrolysis

Materials science

Heat of combustion

Exergy efficiency

Waste management

Organic chemistry

Rotary kiln

Polyethylene

Combustion

Kiln

Environmental science

Composite material

Chemistry

Exergy

Process Safety and Environmental Protection

Energy and exergy analysis is a practical thermodynamic method to assess the potentiality of waste-to-energy technologies. In this study, plastic wastes were pyrolyzed in a rotary kiln to recover energy products including gas, oil and char. The effects of heat carrier loading in the kiln and plastic waste types on the pyrolysis process, including carbon distribution, properties of liquid oil/gas, energy and exergy of products, were investigated. Heat carrier loading could enhance the energy and exergy efficiency of the pyrolysis process. The exergy and energy efficiencies of the plastic mixture pyrolysis are in the range of 60.9 %–67.3 % and 59.4–66.0 %, respectively. The energy consumption ratio of polyethylene pyrolysis with 15 % heat carrier loading and plastic mixture pyrolysis with 20 % heat carrier loading showed that the pyrolysis could achieve self-heating by combusting some recycled gas and char products. This work provided an reliable assessment of potentiality of pyrolysis with heat carrier for converting plastic wastes into fuels.

Exergy and energy analysis of pyrolysis of plastic wastes in rotary kiln with heat carrier