Hydrothermal liquefaction of sewage sludge under isothermal and fast conditions

Lili Qian, Shuzhong Wang, Phillip E. Savage

Research output: Contribution to journalArticlepeer-review

144 Scopus citations


We investigated the effects of water loading, sludge moisture content, recovery solvent, and additives on the product yields and compositions from isothermal (673 K, 60 min) and fast (773 K, 1 min) hydrothermal liquefaction (HTL) of sewage sludge. The water loading (which affects pressure within the reactor) plays a small role in product yields. The sludge moisture content had a larger effect with the highest biocrude yields (26.8 wt% from isothermal HTL and 27.5 wt% from fast HTL) being produced from sludge that was 85 wt% moisture. The HTL biocrude from sludge mainly contains long-chain aliphatic hydrocarbon moieties and aliphatic acids. Dichloromethane recovered more biocrude and energy content (∼50%) than did the other solvents tested. Added K2CO3, Na2CO3, HCOOH, CH3COOH, MoO3-CoO/γ-Al2O3and Ru/C significantly decrease the biocrude yield when their loadings are 50 wt% of the dried sludge. The additives, excepting carbonates, enhance gasification of sludge.

Original languageEnglish (US)
Pages (from-to)27-34
Number of pages8
JournalBioresource technology
StatePublished - Jan 1 2017

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Environmental Engineering
  • Renewable Energy, Sustainability and the Environment
  • Waste Management and Disposal


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