(143a) "Enhanced Bio-Oil and Biochar Properties from Microalgae through Torrefaction Pretreatment Followed By Fast Pyrolysis"

The growing need for sustainable energy solutions has prompted investigations into the synthesis of biochar and bio-oil via the pyrolysis of biomass. Microalgae is a viable feedstock because of its high lipid and carbohydrate content. The high oxygen concentration, high viscosity, and poor calorific value of the bio-oil and biochar produced from untreated microalgae by fast pyrolysis, however, nevertheless result in unsatisfactory-grade products. The purpose of this work is to examine the upgrading of bio-oil and biochar by the pretreatment of microalgae before they undergo fast pyrolysis. By lowering moisture, oxygen content, and volatile chemicals, torrefaction—a gentle thermal treatment carried out at 200–300 °C in an inert atmosphere—improves the chemical composition of microalgae and increases feedstock stability and energy density. In this work, Chlorella pyrenoidosa was torrefied and subsequently pyrolyzed in a fast pyrolysis reactor at temperatures ranging from 450–550 °C. GC-MS and elemental analysis were used to examine the impacts of torrefaction on the composition of bio-oil, including decreased acidity, increased carbon content, and enhanced heating value. Similar to this, BET analysis was used to look at the surface area and porosity of biochar, two of its structural characteristics. The findings show that torrefaction considerably improves both biochar and biooil, with the latter being more suited for advanced applications such as supercapacitors and soil amendment and the former being more suitable for fuel applications. This pretreatment technique provides a workable way to increase the microalgae biofuel production's economic and environmental viability.