Bio-oil production from hydrothermal liquefaction of ultrasonic pre-treated Spirulina platensis

Hydrothermal liquefaction (HTL) of renewable microalgae is a potential promising technology for liquid biofuel production. This paper investigated the effect of ultrasonic pre-treatment of microalgae (Spirulina platensis) on HTL products distribution and oil quality. Cell disruption was enhanced with increasing of ultrasonic power and time. Liquefaction was promoted by larger ultrasonic power, but restrained by prolonged pre-processing time. Such promotion was found more pronounced at relatively lower liquefaction temperature. Combined with FT-IR, GC-MS and TG analysis, the ultrasonic pre-treatment increased the compounds at lower boiling point within the biocrude oil. The distillation characters of the hydrothermal oils were more near to the heavy Iraqi crude, with only 22 wt% in distillation zone of diesel.