A kinetic model for hydrothermal liquefaction (HTL) of algal biomass is proposed to predict the product distribution. This model is developed based on the experimental results obtained from a batch reactor. The experiments were conducted to study the effects of variations in biochemical composition of algal biomass produced at different time points of a heterotrophically grown culture under photosynthesis adaptation. The developed model is validated with the HTL experimental results available in literature. Along with the model development, the product distribution behavior is also studied at different experimental conditions. A micro bomb calorimeter is used to determine the high heating value (HHV) of the biocrude oil and bio-char. The biocrude oils and water soluble organic compounds were characterized with the High-Throughput Time of Flight Mass Spectrometer (HT TOF-MS) and GC-MS. Various analytical methods are used to study the behavior of lipids, proteins, amino acids, carbohydrates and other water soluble compounds.