Synergistic Mechanisms and Product Regulation in the Co-Pyrolysis of Biomass and Food Packaging Waste: A Study Based on Reaction Kinetics and GHG Calculation

TL;DR

This study explores how co-pyrolysis of biomass and plastic waste can produce valuable hydrocarbons while reducing environmental impact.

Contribution

The study reveals synergistic effects of polypropylene in co-pyrolysis, enhancing reaction kinetics and hydrocarbon yield.

Findings

Adding polypropylene reduces activation energy and promotes deoxygenation in co-pyrolysis.

Co-pyrolysis of corn stover and polypropylene increases hydrocarbon yield to 65.6% at 600°C.

A natural gas-assisted process yields 1835 RMB daily profit and cuts CO2 emissions by 6515 tons annually.

Abstract

To address the mounting environmental burden caused by solid waste from the food supply chain—specifically agricultural residues and plastic packaging—this study systematically investigated the synergistic mechanisms and product regulation pathways in the co-pyrolysis of four representative food processing by-products—rice husk, pine wood, corn stover, and chestnut shell—with polypropylene, a common food packaging material. A comprehensive methodology integrating thermogravimetric analysis, kinetic modeling, and product characterization was employed. The results demonstrate that incorporating polypropylene into co-pyrolysis systems, such as those involving waste oil, significantly reduces the average activation energy, indicating a catalytic effect that enhances reaction kinetics. Notably, the co-catalytic interaction between corn stover and PP led to a substantial 54.90% reduction in oxygen content, underscoring PP’s role as an effective hydrogen donor that promotes deoxygenation and free radical reactions, thereby increasing hydrocarbon production. At an optimal pyrolysis temperature of 600 °C, product distribution was effectively regulated: the hydrocarbon yield in the CP (corn stover/PP) system increased from 39.8% to a maximum of 65.6%, reflecting a targeted conversion of oxygenated compounds into high-value hydrocarbons. Furthermore, greenhouse gas (GHG) emission calculation and techno-economic analyses indicate that a natural gas-assisted co-pyrolysis process (Scenario C) can generate a net daily profit of 1835 RMB while reducing annual CO2 emissions by 6515 tons, demonstrating both economic feasibility and environmental benefits. This study provides a theoretical foundation for the circular economy in the food industry, offering a viable technical pathway for the simultaneous treatment of organic food waste and packaging plastics, thereby supporting the sustainable development of the agri-food sector.

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