ABSTRACT
The biochemical composition of algal biomass makes algae a promising source to produce different low-carbon biofuels through chemical, thermochemical and biochemical conversion techniques. Among these processes, thermochemical conversion pathways, i.e., pyrolysis and hydrothermal liquefaction, gained spatial attention to produce syngas, bio-oil and biochar using different micro- and macroalgal species. Bio-oil produced via thermochemical conversion technologies had a higher heating value ranging from 24.6 MJ/kg to 41 MJ/kg that has the potential to complement crude oil in petroleum refineries. The quality of the bio-oil, biochar and gas that were produced via thermochemical conversion pathways was strongly influenced by algal biomass biochemical and elemental compositions and process variables such as pyrolysis heating rate, temperature, catalyst (type and amount), solvent-to-biomass ratio and residence time. Hence, this chapter provides review information on the biological (carbohydrate, protein and lipid), elemental and proximate compositions of various macroalgal and microalgal species along with their thermochemical conversion routes to produce bio-oil.
