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

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 degrees C, 20 degrees 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 hy-drocarbon selectivity. Adding treated eggshells and activated biochar as catalysts significantly increased aro -matic 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.

Automated summary

The presence of emerging impurities in food waste, such as plastic, chopsticks, eggshell, and bones, has hindered the sustainable treatment and utilization of food waste. This study investigated the conversion of food waste into pyrolysis oil and evaluated the effect of different impurities. It was found that certain impurities, like polypropylene, improved the organic fraction of the pyrolysis oil, while others reduced the selectivity of hydrocarbons. The addition of treated eggshells and activated biochar as catalysts increased the production of aromatic and aliphatic hydrocarbons with higher heating values.