Microalgae processing for jet fuel production

Abstract

AbstractThis study focuses on the laboratory production of jet fuel from microalgae. In contrast with many studies that use partial nutrient starvation to boost lipid content of the species, physiological modification was undertaken under complete nutrient starvation for 3 days to increase lipid content beyond 80%. This was followed by biomass harvesting, which was necessary for downstream processes. Large amounts of biomass were achieved between day 8 and day 10 during the cultivation period, with temperatures ranging between 15 and 35 °C under constant luminance of 1000 lux and daily supply of CO2 for 15 days. It was found that Nannochloropsis sp. grew effectively between 15 °C and 25 °C with more biomass produced in the same temperature range. Conversion processes involved steps such as oil extraction, thermal cracking without catalyst at 300 °C and fractionation between 70 °C and 250 °C. The pyrolysis of bio‐oil was also undertaken as a fast cracking process for the temperature ranging between 350 °C and 450 °C within 12 s. Some parameters such as flash point, net heat of combustion, sulfur, and viscosity complied with ASTM standards. Jet fuel from microalgae therefore shows potential despite many challenges related to cost effectiveness and sustainability. In order to obtain a bio‐jet fuel that is completely compliant with ASTM standards, upgrading, reforming processes, and the use of additives will be needed more, especially for pilot and large‐scale production once fuel sustainability is achieved. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd