Sequential Hydrothermal Processing of Sewage Sludge to Produce Low Nitrogen Biocrude

A hydrothermal pre-treatment has been developed to improve sewage sludge quality or produce low nitrogen biocrude via liquefaction (HTL) in a subsequent step. The mild (150 °C) step was performed with deionized water, sulfuric acid (0.5 M), citric M) solubilize containing compounds the aqueous supernatant. Downstream, residual solid material liquefied addition of sodium carbonate (350 °C). transferred up 66.7 wt. % into supernatant, while 62.0 carbon recovered solid. Due lipids retained solid, which increased favored yield 42.9 and evaluating value H/Ceff ratio significantly 1.48. Multi-method characterization resulted samples showed lower concentration N-heterocycles, long-chain aliphatics free fatty are increased.