Hydrothermal liquefaction of algal biomass to bio-oil

This chapter focuses on the hydrothermal liquefaction of algal biomass to bio-oil. This includes discussion of the physical properties of water under subcritical conditions that are relevant to the liquefaction of biomass components—lignocellulose, proteins, and lipids. This also covers process intensification approaches such as the use of microwave irradiation and addition of supercritical carbon dioxide for liquefaction rate enhancement, improvement of yield, and product quality. The application of carbon-based and metal oxide-based catalysts is discussed together with the parameters such as temperature, salinity, and nutrient concentration that affect the reaction. Lastly, some reaction mechanisms involved in the process are also covered.