Hydrothermal liquefaction of Chlorella pyrenoidosa in sub- and supercritical ethanol with heterogeneous catalysts

► The highest mass and energy recovery ratios of bio-crude were 71.3% and 101.8%. ► Temperature was found to be the most dominant parameter on HTL process. ► H2 as a processing gas improved the bio-crude yield and quality. ► The mass ratio of the reacted ethanol to the dry alga was about 3.26.