Elucidating synergistic effects during co-pyrolysis of plastics and paper in municipal solid waste: Thermal behavior and product characteristics

Plastics and paper are common components of municipal solid waste (MSW), making an in-depth understanding of their interactions essential for MSW thermal conversion. In this study, the co-pyrolysis behavior of plastic and paper was investigated. Firstly, the thermal decomposition characteristics were analyzed. Secondly, the pyrolytic behavior was elucidated in a fixed-bed reactor. Thirdly, the impact of plastic melting on co-pyrolysis was clarified. Results indicated that the thermal decomposition was accelerated between 250 °C and 283 °C, while temperatures above 400 °C resulted in inhibition. During fixed-bed pyrolysis, char yields (70.7-16.9 %) were increased by 4.0 %-12.7 %. This increase was mainly due to plastic melting, which contributed 8.6 % and increased aliphatic carbon content. Besides, PVC and PET exhibited a broader melting range > 500 °C. Bio-oil yields (25.5-70.6 %) were reduced by 3.4 %-12.4 %, primarily affecting aliphatic compositions. Gas yields (3.8-6.5 %) were reduced < 400 °C but increased with temperature, involving primarily H₂, CH₄, C₂H₄, and C₂H₆.