Plastic waste management via thermochemical conversion of plastics into fuel: a review

Growing non-biodegradable waste plastics pose a significant environmental challenge that cannot be addressed by conventional methods alone. Therefore, alternative waste management methods such as plastic-to-fuel methods that convert waste plastics into valuable biofuels via thermochemical degradation must be investigated. Waste plastic pyrolysis and gasification are popular plastic-to-fuel technologies that will be instrumental in circular economies. Therefore, they must be discussed and compared to highlight their advantages and limitations in-process and techno-economic feasibility. Thus, this paper tries to reach three technologies: microwave-assisted pyrolysis, supercritical water gasification, and plasma gasification, highlighting their strengths and weaknesses. It appears that the diesel-like pyrolysis oil from microwave pyrolysis can be used in internal combustion engines to mitigate fossil fuel dependence. Moreover, gasification technologies could help in the growth of integrated biorefineries that can extract hydrogen from syngas to produce value-added chemicals. It is anticipated that their industrial-scale implementation could be beneficial for landfill reclamation and mitigation of plastic-related environmental harm. However, these technologies are currently at low technology readiness levels. Therefore, more studies are required to spotlight their in-depth techno-economic feasibility and provide a research direction to economize these technologies further to maximize their economic rate of return.