Valorization of food waste impurities by catalytic co-pyrolysis for production of pyrolysis oil with high energy potential

• Published in: Journal of analytical and applied pyrolysis Vol. 170; p. 105918
• Main Authors: Okopi, Solomon Inalegwu, Wang, Jiayu, Kong, Wenzhuo, Yu, Zhaozhuo, Ndudi, Efomah Andrew, Che, Lei, Gu, Zhaolin, Xu, Fuqing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2023
• Subjects: Bioenergy; Catalyst; Food waste; Food waste impurities; Pyrolysis oil; Food waste; Food waste impurities; Pyrolysis oil; Bioenergy; Catalyst
• ISSN: 0165-2370; 1873-250X
• DOI: 10.1016/j.jaap.2023.105918

The emerging impurities (plastic, chopsticks, eggshell and bones) in food waste (FW) due to inefficient source separation have hindered the sustainable treatment and valorization of FW. This study evaluated pyrolysis for converting FW with and without different impurities to produce pyrolysis oil (py-oil). The optimal yield of total condensable vapor (py-liquid) of 37.52 wt% from pure FW was achieved at 400 °C, 20 °C/min and 20 min. Different FW impurities demonstrated varieties of relative content of hydrocarbon (35.53 wt% − 58.03 wt%). The introduction of polypropylene, eggshells and bones improved the organic fraction of py-liquid from 6.5 wt% to 10.7 wt%. Polypropylene enhanced the selectivity of hydrocarbons, while other impurities reduced the hydrocarbon selectivity. Adding treated eggshells and activated biochar as catalysts significantly increased aromatic and aliphatic hydrocarbon production with higher heating values (HHV) ranging from 36 MJ/kg - 44.44 MJ/kg. The C-H and C-O ratio of py-oil indicated that py-oil has the potential to be processed and utilized like conventional liquid fuel. •Effects of impurities on food waste (FW) catalytic pyrolysis were investigated.•Impurities generally reduced py-liquid yield but some can improve the oil quality.•Eggshells and bones demonstrated catalytic behavior for py-oil quality improvement.•Activated FW biochar catalysts showed high selectivity of hydrocarbons in co-pyrolysis.•Py-oil from FW pyrolysis catalyzed with treated eggshell revealed the highest high heating value.