Techno-economic review of pyrolysis and gasification plants for thermochemical recovery of plastic waste and economic viability assessment of small-scale implementation

Polymers used in the production of consumer products become a part of municipal waste streams after reaching the end of their useful life span, but also before even reaching markets, as rejects, scraps, and/or industry by-products as a part of industrial waste streams. Suitability for recovery of industrial wastes differs significantly and needs to be analyzed separately. In this research, a review of the techno-economic parameters of existing recovery plants is done. Dependences between economic and technological parameters, sizes, and types of plants, as well as the composition of input material, are derived. Based on the presented data, a techno-economic analysis of the small-scale implementation of thermochemical recovery plants, for industry-generated residual plastic waste fraction, is conducted. Results show that thermochemical conversion of industrial plastic waste cannot be economically viable on a small scale without a gate fee. Pyrolysis plants brake even gate fee is on the level of over 50/86 €/t, while treating only 51%/28% of residual waste, due to strict restrictions regarding feedstock composition. In the case of gasification, it is on the level of 70 €/t, while treating 92% of available waste. Pyrolysis is the only viable solution for treating up to 12 TPD after which gasification also becomes a viable option. Usual capacities are up to 25/100 TPD for pyrolysis/gasification, after which incineration-based technologies need to be considered. The presented results provide decision-makers with a good overview of alternative thermochemical conversion technologies, their technical characteristics, limitations, and possible economic outcomes of their implementation. Graphical abstract