A quantitative kinetic model for the fast and isothermal hydrothermal liquefaction of Nannochloropsis sp.

David C. Hietala, Julia L. Faeth, Phillip E. Savage

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Hydrothermal liquefaction (HTL) is a technology for converting algal biomass into biocrude oil and high-value products. To elucidate the underlying kinetics for this process, we conducted isothermal and non-isothermal reactions over a broad range of holding times (10 s-60 min), temperatures (100-400 °C), and average heating rates (110-350 °C min-1). Biocrude reached high yields (≥37 wt%) within 2 min for heat-source set-point temperatures of 350 °C or higher. We developed a microalgal HTL kinetic model valid from 10 s to 60 min, including significantly shorter timescales (10 s-10 min) than any previous model. The model predicts that up to 46 wt% biocrude yields are achievable at 400 °C and 1 min, reaffirming the utility of short holding times and "fast" HTL. We highlight potential trade-offs between maximizing biocrude quantity and facilitating aqueous phase recovery, which may improve biocrude quality.

Original languageEnglish (US)
Pages (from-to)102-111
Number of pages10
JournalBioresource technology
StatePublished - Aug 1 2016


All Science Journal Classification (ASJC) codes

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

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