Pyrolysis of municipal solid waste in a fluidized bed for producing valuable pyrolytic oils

In order to recover valuable pyrolytic oils, mixed municipal solid waste was pyrolyzed in a fluidized bed reactor. Results showed that liquid products yielded among 38.4–56.5 wt% and separated into water-soluble phases and organic phases. Moisture was concentrated in the water-soluble phases (39.4–57.3 wt%), making them low in carbon content and heating value. On the other hand, the higher carbon content and lower oxygen content of organic phases make their heating value (27.5–32.1 MJ/kg) and quality higher than bio-oils. Water-soluble phases mainly included acids, carboxylics, phenols, and sugars, which could be used as chemical feedstocks and substantial fuel. Organic phases mostly contained aromatics and phenols and could be used as fossil fuels directly or as chemical materials. Heavy metals of Cd and Pb were proved to be poor in both water-soluble phases and organic phases. As for Zn, it was found to be higher in the water-soluble phases at 450 and 550 °C with quartz sand as bed material than that in crude oils. However, Zn content in organic phases was comparable to crude oils. High-aluminum bauxite and attapulgite as bed materials increased heating value of water-soluble phases and organic phases respectively, and both performed well in reducing the Zn content of water-soluble phases. This work proved that it was an operative way to produce valuable pyrolytic oils by pyrolysis of mixed municipal solid waste.