Hydrothermal Liquefaction of Loblolly Pine: Effectsof Various Wastes on Produced Biocrude

摘要

In this study, feedstock interaction of cow manure and digested sewage sludge on hydrothermal liquefaction (HTL) of loblolly pine (LP) was evaluated. Noncatalytic HTL experiments were performed at reaction temperatures of 250, 275, and 300 °C at a constant reaction time of 30 min. Cyclohexane and acetone were used for biocrude extraction separately. The study focuses on the characteristics of the produced biocrude, and thus, physicochemical properties of biocrudes were examined by gas chromatography–mass spectrometry, Fourier-transform infrared spectroscopy, density, and viscosity measurements, in addition to comparing mass and energy yields. On a LP basis, the biocrude yield reached as high as 30 and 17% for acetone and cyclohexane extraction, respectively, at the highest reaction temperature. Elemental carbon and energy contents increased with increasing HTL temperature for all cases. Alkalinity of the HTL process liquid (aqueous phase) increases from the HTL of sludge, and thus, it favored the formation of nonpolar compounds in biocrude. On the other hand, acidity of the reactionmedium increases with the HTL of manure and pine, and thus, phenoliccompounds in biocrude were increasing. Cyclohexane was more effectivefor sludge/LP biocrude extraction, whereas acetone was effective formanure/LP. Density of cyclohexane extracted sludge/LP biocrudes at300 °C was less than 1000 kg m^–3, whereas acetone-extractedbiocrudes had densities greater than 1000 kg m^–3. For all the biocrudes, viscosity was reduced considerably for themixtures when compared to biocrudes from LP alone.