This paper presents the studies on the effect of three process parameters; temperature, pressure and
reaction time on the subcritical and supercritical hydrothermal liquefaction of oil palm empty fruit
bunch, palm mesocarp fiber and palm kernel shell. The effect of temperature (330–390 C), pressure
(25–35 MPa) and reaction time (30–240 min) on bio-oil yields were investigated using a Inconel batch
reactor. The optimum liquefaction condition for empty fruit bunch, palm mesocarp fiber and palm kernel
shell was at supercritical condition of water; 390 C and 25 MPa. For the effect of reaction time, bio-oil
from empty fruit bunch and palm mesocarp fiber attained maximum yields at 120 min, whereas
bio-oil yield from palm kernel shell continued to increase at reaction time of 240 min. Lastly, a life cycle
assessment based on a conceptual biomass hydrothermal liquefaction process for bio-oil production was
constructed and presented.