Reza Azin

In this work, a global kinetic model of hydrothermal liquefaction (HTL) is proposed for Aurantiochytrium sp., C. protothecoides, Scenedesmus sp., Chlorella vulgaris, and Tetraselmis sp. algae. Proteins, lipids, and carbohydrates were first decomposed to the aqueous phase and biocrude, followed by further decomposition to the gas phase. MATLAB optimization function was used to optimize the kinetic parameters of different algae. Furthermore, economic analysis was evaluated by using global kinetic modeling to estimate HTL product yields in Aspen Plus. The results showed that the calculated optimum values of activation energies were 31–50, 32–52, and 46–90 kJ/mol for the conversion of proteins, lipids, and carbohydrates to biocrude. Also, the global kinetic model had a great predictive ability with a reduced chi-square of 0.717 and R-squared of 0.987. Moreover, the application of the global kinetic model for different biomass such as Chlorella vulgaris, sewage sludge, green waste, food waste, grease residue, and their 50:50 mixtures with Chlorella was evaluated. The yields of Chlorella vulgaris, green waste, food waste, and their mixture with Chlorella could be predicted by the kinetic parameters of Scenedesmus sp., while kinetic parameters of Aurantiochytrium sp. were more appropriate for yield predicting of grease residue. Moreover, HTL techno-economic analysis of Aurantiochytrium sp. showed that the various ranges of the minimum fuel selling price (MFSP) were estimated to be $2.11 to $7.52/GGE by the effect of biomass price.