Elemental migration and transformation during hydrothermal liquefaction of biomass

Over the past few decades, energy and environmental crises have worsened due to the excessive consumption of fossil fuels. Hydrothermal liquefaction (HTL) is a promising technology for sustainable biocrude production from biomass. However, elemental migration and transformation during HTL of biomass have only received scant attention to date. Understanding the transformation mechanism is beneficial for downstream biocrude upgrading and by-products utilization for the future industrialization of HTL. In this paper, biomass is grouped into six categories: microalgae, macroalgae, lignocellulose, food waste, manure, and sludge. The biochemical composition and HTL product distribution of six kinds of biomass are compared. The conversion process of the biomacromolecules (including lipids, proteins, cellulose, hemicellulose, and lignin) and the interactions between them are also reported. Furthermore, the distribution of carbon, nitrogen, sulfur, and inorganic elements (Na, K, Ca, Mg, Al, Fe, Zn, Cu, Pb, Cd, etc.) in the HTL products is summarized, and the transformation of the organic and inorganic elements during HTL of biomass is explored. Finally, outlooks for the HTL of biomass are proposed.

Automated summary

This paper investigates the application of hydrothermal liquefaction (HTL) technology in various types of biomass, compares the biochemical composition and product distribution of biomass, and explores the transformation of organic and inorganic elements in biomass during the HTL process. The research findings contribute to the future industrialization of HTL and the upgrading of biocrude.