Hydrothermal liquefaction of algae for fuel and chemicals

This research was a continuation of the first project. Algae has been widely used for biocrude feedstock, but this was the first research attempt to produce algal biocrude under an ethylene environment along with inert(nitrogen) and other reactive gases: hydrogen and oxygen. The selected algae species was Tetraselmis sp. which can grow fast in almost any salinity level of growth medium and does not need arable land to cultivate. Besides the reduced form of red mud (RRM) catalyst from previous project, the transition metal, nickel (Ni) was incorporated on red mud support (termed as Ni/RM) to enhance the catalytic activity. The mutual effect of Ni/RM catalyst and ethylene gas was found by the increased biocrude production. On the other hand, the reduced red mud catalyst minimized the harmful heavy metal and phosphorus transfer from the algal feedstock to biocrude in studied gaseous ambiences. Among the non-catalytic experiments, the hydrogen gas optimized carbon content and energy content with minimum oxygen amount in biocrudes. I was responsible for the formulation of experimental design, conducting experiments, collecting data and documenting the results as research article which ultimately has become the second research objective of my doctoral course. The second part of this project explored the blending effects of algal biocrude (produced by me) and the non-edible vegetable oil named carinata oil over hydrotreatment process. It was a PhD objective of my colleague where I played an important role for algal biocrude production, characterization, helping my colleague to characterize her end products and helping to write the research article by various suggestion and fruitful discussion. We compared the performance of commercial catalyst of Cobalt-Molybdenum on Alumina support (CoMo/Al) and our synthesized sulfided or unsulfided cobalt-molybdenum on Douglas fir biomass derived biochar support (CoMo/DF), catalysts for upgrading techniques.The commercial catalyst increased the upgraded yield from blended oil but our catalyst lowered the viscosity, nitrogen content and sulfur content of upgraded oil compared to the commercial catalyst. Moreover, the Douglas fir derived biochar support (DF) of CoMo/DF catalyst absorbed the metal from the oil. Thus, our catalyst performed better, and mixing oils provided improved results.

Check the published articles on Algae treatment
- Influence of red mud catalyst and reaction atmosphere on hydrothermal liquefaction of algae’, Energies 2023, 16, 491. DOI: https://doi.org/10.3390/en16010491

- Understanding the effects of feedstock blending and catalyst support on hydrotreatment of algae HTL biocrude with non-edible vegetable oil’, Energy Conversion and Management, Volume 268, 15 Sept2022,115998.DOI:https://doi.org/10.1016/j.enconman.2022.115998