Role of Species, Pretreatment, and Lipid Extraction Conditions in Hydrodeoxygenation and Hydroisomerization of Algae Oils to Hydrocarbon Fuels

Microalgae are one of the most promising sources of biomass for renewable fuels and chemicals due to their high growth rate and potentially favorable chemical composition.  Although esterification and transesterification of fatty acids and triglycerides to biodiesel has traditionally been a strong driver of algae research and development, interest in fully-deoxygenated fuels in the diesel and jet fuel range has significantly increased.  From algal lipids, a two-step process involving 1. Hydrodeoxygenation (HDO) and 2. Hydroisomerization (HI) is likely required to produce fungible fuels.  However, it is unknown how algal species, pretreatment conditions, and lipid extraction processes affect the quality of the extracted lipid fraction.  To explore the effects of these parameters on HDO and HI, we have conducted a systematic study with multiple algae species and lipid preparation conditions.  We report detailed characterization of the extracted lipids and performance of the different lipids over representative HDO and HI catalysts under optimized reaction conditions of H₂ pressure, temperature, and space velocity.