(298e) Comparative Techno-Economic Analysis of Producing High-Value Chemicals and Fuels from Waste Plastic Via Conventional Pyrolysis and Thermal Oxo-Degradation.

The rapid rise in global plastic production in recent decades has resulted in a massive generation of plastic waste. Over 75% of the plastic waste generated in the United States was sent to landfill, with a meager 8.7% recycled [1], [2]. Chemical recycling of plastic waste is gaining more attention, and the thermochemical decomposition of waste plastics into valuable chemicals and liquid fuel is being researched and developed. However, there are few studies on the economic feasibility of this pathway for dealing with plastic waste[2].

This study conducts a comparative techno-economic analysis on the thermochemical decomposition of waste high-density polyethylene to produce gaseous (ethylene and propylene) and liquid products (naphtha, diesel, and wax range hydrocarbons) via conventional pyrolysis (low residence time and high residence time) and thermal oxo-degradation. The study also included scenarios with pyrolysis oil upgrading.

Preliminary techno-economic analysis showed that the capital cost could range from $45.56 million for thermal oxo-degradation without hydrocracking to 134.33 for conventional pyrolysis scenarios. Scenarios with hydrocracking resulted in annual revenues in the range of $53 million to $58 million, while scenarios without hydrocracking resulted in annual revenues in the range of $21 million to $40 million. However, the net present value (NPV) showed that the most economically favorable scenarios are the scenarios with no hydrocracking with NPVs ranging from $81million to $118 compared to scenarios with hydrocracking ranging from $42million to $80 million as the high revenue could not compensate for the high capital investment. Sensitivity analysis showed that product yield and capital cost have the biggest impact on the process economics of the facilities.

The preliminary result shows that plastic pyrolysis via the different pathways can be economically feasible with scenarios with product upgrading yielding the largest annual revenues but the lowest net present value due to its high capital cost.

References

[1] D. Zhao, X. Wang, J. B. Miller, and G. W. Huber, “The Chemistry and Kinetics of Polyethylene Pyrolysis: A Process to Produce Fuels and Chemicals,” ChemSusChem, vol. 13, no. 7, pp. 1764–1774, Apr. 2020, doi: 10.1002/CSSC.201903434.

[2] Houqian Li et al., “Expanding plastics recycling technologies: chemical aspects, technology status and challenges,” Green Chemistry, 2022, doi: 10.1039/D2GC02588D.