Effects of reaction temperature and reaction time on the hydrothermal liquefaction of demineralized wastewater algal biomass

Hydrothermal liquefaction (HTL) of demineralized wastewater algal biomass was studied under different reaction temperatures (260–320 °C) and time (0–90 min). A moderate reaction condition (280 °C, 60 min) was found sufficient to produce the highest oil yield (~26% daf). Analysis of this oil showed a potential distillation recovery of 71% at 400 °C (mostly in the jet fuel to fuel oil range). All oils obtained have a comparable HHV (35.20–36.76 MJ/Kg) similar to tar (36 MJ/kg). GC–MS analysis showed that the oils derived are comparable, except at extreme reaction conditions (320 °C, 60 min) where a better fuel component in terms of hydrocarbons and N&O-heterocyclic compounds was achieved. The energy consumption ratio (ECR) of oils from demineralized biomass (0.37–0.45) is 80–120% lower compared to that of untreated biomass (ECR = 0.85) at 300 °C and 60 min.