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Liquefaction of Sewage Sludge To Produce Bio-oil in Different Organic Solvents with In Situ Hydrogenation

Li, Rundong, Teng, Wenchao, Li, Yanlong, Liu, Enhui
Energy & fuels 2019 v.33 no.8 pp. 7415-7423
acetone, amides, biofuels, esters, ethanol, heat, heterocyclic compounds, hydrogenation, liquefaction, methanol, oxygen, petroleum, sewage sludge, solvents, temperature, thermogravimetry, weight loss
Liquefaction is a new method of producing crude oil from sewage sludge. The effect of in situ hydrogenation on sewage sludge liquefaction characteristics using different solvents was studied in this research. The highest bio-oil yields were 42.3% in ethanol at 360 °C, 43.1% in acetone at 360 °C, and 26.3% in methanol at 280 °C. Esters were the main components of bio-oils in ethanol and methanol, which comprised 43.55% ethyl esters and 61.05% methyl esters, respectively. N components originating from protein constituted the main heterocyclic compounds and amides. The oxygen content decreased as the temperature increased, and the highest higher heating values for ethanol, acetone, and methanol at 360 °C were 29.08, 29.53, and 27.95 MJ/kg, respectively. The differential scanning calorimetry–thermogravimetry–derivative thermogravimetry results illuminated that the bio-oil obtained from methanol was more stable than the others and the main small-molecule components decomposed before the temperature reached 373.5 °C. The highest weight loss rates were 4.31, 5.07, and 5.12%/min at 238.8, 233.6, and 260.5 °C, respectively.