Production of furfural and levoglucosan from typical agricultural wastes via pyrolysis coupled with hydrothermal conversion: Influence of temperature and raw materials.

The liquid product from biomass direct pyrolysis is usually complex and difficult to effectively utilize. By combining hydrothermal conversion and low-temperature pyrolysis, the hemicellulose and cellulose of biomass can be transformed into value-added furfural and levoglucosan (LG), respectively. The effects of temperature during hydrothermal treatment (160-240 °C) and subsequent pyrolysis (340-400 °C) on the production of furfural and LG were investigated by using three typical agricultural wastes, namely corn stalk, peanut shells, and rice stalk. The maximum furfural yield of 4.2% was achieved upon hydrolysis of peanut shells at 200 °C. The hydrochar produced from peanut shells presented the highest LG yield of 7.3% (based on original biomass weight) for a pyrolysis temperature of 360 °C. Under this optimal condition, the total revenue from various products of the hybrid thermochemical process was estimated at $0.362 per kilogram of peanut shells, whereas furfural and LG account for 90% of the revenue.