The Influence of Lipids on the Fate of Nitrogen during Hydrothermal Liquefaction of Protein-containing Biomass

Publication date: Available online 15 February 2020Source: Journal of Analytical and Applied PyrolysisAuthor(s): Y. Fan, U. Hornung, K. Raffelt, N. DahmenAbstractHydrothermal liquefaction (HTL) of carbohydrate (lactose), protein (lysine), and lipid (palmitic acid) surrogates was carried out in batch reactors for 20 min in a temperature range of 250 to 350 °C in order to understand interactions in hydrothermal reactions. A binary mixture of lysine and lactose leads to a higher bio-oil yield when compared to experiments made with isolated compounds, indicating a relevant contribution by Maillard reactions (MRs). Emulsification happens to proteins and lipids during HTL, making it difficult to separate and collect bio-oil products at low temperatures. When testing the ternary mixture, the nitrogen content of the bio-oil is negligibly affected by the changes of temperature, presenting a constant value of 5.3 wt. %. However, adding lipids dramatically changes the bio-oil composition. This is indicated by an increasing amount of fatty acid amides and a decrease in Maillard reaction products, suggesting a strong competition between amidation and MRs. A reaction scheme was proposed based on the final products and assumed reaction pathways. These findings here can contribute to a better understanding of the HTL of biomasses with complex organic compositions.
Source: Journal of Analytical and Applied Pyrolysis - Category: Chemistry Source Type: research