This presentation introduces a catalyst-free process combining wet in situ transesterification and hydrothermal liquefaction (iTHL) for the production of various type of fuels including fatty acid alkyl ester (FAAE, biodiesel) and platform chemicals from non-dried biomass. First, iTHL was applied to harvested microalgae that contain 80 w/w% moisture for the selective production of alkyl esters. Using microalgae as an input biomass, iTHL was tested by varying the temperature (160 to 200oC), solvent type and amount (0.1 to 2.5 ml / g dry algae), and alcohol amount (3 to 5 ml / g dry algae). At temperature above 160oC, it was found that the SolvCl (dichloromethane, chloroform, and 1,2-dichloroethane (DCE)) enhanced the biocrude production by providing a small amount of HCl in an ionized form that can act as an acid catalyst (SN2 reaction mechanism involved). In iTHL using N. gaditana, the most effective solvent is DCE with the FAEE selectivity in biocrude equal to 91.85 % (maximum transesterifiable lipid basis) and the experimental results with both Nannochloropsis and Chlorella species provide a possibility of the process applicable to the other algal species and biomass. Having this idea, this iTHL process applied to spent coffee ground (SCG), which is considered as a waste, and produce not only FAAE but ethyl levulinate as a co-product. The double role of solvCl in iTHL that provides a biphasic and acidic environment helps direct utilization of wet biomass as a fuel feedstock, therefore provides economic feasibility by eliminating the additional acid catalyst and the energy intensive drying process of biomass.

Application of a combined wet in situ transesterification and hydrothermal liquefaction (iTHL) for the catalyst-free production of fuels from non-dried biomass

2019 Fall National Meeting

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