Biocrude Production by Hydrothermal Liquefaction from Seaweed Residues

Abstract

The development of new technologies to replace conventional fossil fuel energy sources is crucial for transitioning to a sustainable production system that better manages available resources, such as the Circular Economy. One potential solution is the revaluation of organic waste into raw materials through thermal treatment. Hydrothermal liquefaction (HTL) is a technology that produces biocrude from organic matter, through a reaction in an aqueous medium at elevated temperatures and pressures below the critical point of water. The organic matter treated in this case is a microalgae-bacteria consortium from the biological treatment of an effluent loaded with nutrients and organic matter generated by a marine aquaculture facility that produces sole. The aim of this study is to investigate the impact of key variables, namely temperature (240-300 ºC), initial biomass load (5-15 % w/w), and reaction time (20-60 min), on biocrude yields and their higher heating value (HHV). The highest biocrude yield (18.18%) was achieved at 270 ºC, 40 min, and 5 % w/w, while the highest HHV (37.1 MJ/kg) was obtained at 300 ºC, 40 min, and 10 % w/w.