| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4471724 | Waste Management | 2013 | 8 Pages |
•This study focuses on sewage sludge direct liquefaction in supercritical water.•A self designed high-pressure reaction system is set up.•Temperature and residence time are the most effective factors in this conversion.•Supercritical water lowers the temperature corresponding maximum bio-oil yield.•Bio-oil from sewage sludge exhibits good fuel properties.
Environment-friendly treatment of sewage sludge has become tremendously important. Conversion of sewage sludge into energy products by environment-friendly conversion process, with its energy recovery and environmental benefits, is being paid significant attention. Direct liquefaction of sewage sludge into bio-oils with supercritical water (SCW) was therefore put forward in this study, as de-water usually requiring intensive energy input is not necessary in this direct liquefaction. Supercritical water may act as a strong solvent and also a reactant, as well as catalyst promoting reaction process. Experiments were carried out in a self designed high-pressure reaction system with varying operating conditions. Through orthogonal experiments, it was found that temperature and residence time dominated on bio-oil yield compared with other operating parameters. Temperature from 350 to 500 °C and reaction residence time of 0, 30, 60 min were accordingly investigated in details, respectively. Under supercritical conversion, the maximum bio-oil yield could achieve 39.73%, which was performed at 375 °C and 0 min reaction residence time. Meanwhile, function of supercritical water was concluded. Fuel property analysis showed the potential of bio-oil application as crude fuel.
