Master's thesis Renewable Energy ENE500 - University of Agder 2017The conversion of microalgae to biocrude by hydrothermal liquefaction (HTL) is
a technology that could reduce the use of fossil fuels. The aim of this study
was to provide insight in the fuel characterization and process analysis of algae
HTL. Three microalgae species were provided for the fuel characterization. The
Phaeodactylum tricornutum algae were received as a slurry, while the
Spirulina platensis and Chlorella vulgaris were received as dried powders. Experiments
by TGA, proximate and ultimate analysis were performed on the three algae
species. A process analysis of algae HTL was carried out in Aspen Plus. Properties
from the algae analysis was used in the simulation model.
Great improvement of the process effciency was obtained by implementing a heat
exchanger in the simulation model. The S: platensis and P: tricornutum algae
obtained 83 % energy effciency in the process analysis, when all the products from
the process were utilized. Water recycling or district heating could further improve
the energy effciency of the system. For fuel characterization, the C: vulgaris algae
had the best properties. In the process analysis, the P: tricornutum algae obtained
the best results. In future work a kinetic simulation should be designed in order
perform yield optimization and increase the accuracy of the system
