Hydrothermal Liquefaction of Cypress: Effect of Water Amount on Structural Characteristics of the Solid Residue

Abstract

Hydrothermal liquefaction of cypress was performed in an autoclave with various amounts of water. The obtained acid-soluble and acid-insoluble solid residues were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, sugar analysis, elemental analysis, and nuclear magnetic resonance to help understand the reaction mechanisms of this process. The characteristics of solid residues were significantly affected by the water amount. Cellulose was more stable at high water amount and hemicelluloses were much more reactive than cellulose. Comparison of nuclear magnetic resonance spectra of milled wood lignin and milled solid residues indicated a significant cleavage of the side chains. The components of milled solid residues were mainly derived from decomposition and repolymerization of lignin. The decomposition of the side chains was substantial for lignin depolymerization during hydrothermal liquefaction.

Comprehensive Feasibility Assessment of Combined Heat, Hydrogen, and Power Production via Hydrothermal Liquefaction of Saccharina japonica

“…At a high ratio of 1/5, liquefaction was not performed well, even at a high temperature of 300 °C. Liu and Li reported that a high amount of H 2 O is suitable for HTL and many organic components in macroalgae are converted to bio-oil . It was considered that the decomposition reaction (HTL) of macroalgae in hot compressed H 2 O was clearly dependent on the H 2 O amount.…”

“…Liu and Li reported that a high amount of H 2 O is suitable for HTL and many organic components in macroalgae are converted to bio-oil. 32 It was considered that the decomposition reaction (HTL) of macroalgae in hot compressed H 2 O was clearly dependent on the H 2 O amount. A minute difference of 0.21% was observed for the macroalgae to water ratio of 1:7 and 1:10.…”

“…On the other hand, the commercial potential of an experimental study can only be highlighted when showcased with supporting economic studies evaluating the process on an industrial scale. There are apparent gaps in studies involving the assessment of large-scale biofuel production via HTL of macroalgae as a feedstock; feasibility studies for the industrial-scale design of HTL using microalgae − are abundant, but for macroalgae , are still scarce.…”

Energy recovery from sewage sludge using hydrothermal processing

“…Nevertheless, further investigations are necessary to gain more insights into gas evolutions. pressure, which should be relevant to more hydrophobic characteristic of hydrochars (Liu and Li, 2014). On the other hand, during HTC of sludge, formation of water soluble oil was favored at lower temperatures while increased temperature led to higher water insoluble heavy oil (HO) yield (Xu and Lancaster, 2008).…”

Metal Ion‐Catalyzed Hydrothermal Liquefaction of Calcium Lignosulfonate in Subcritical Water

“…Several processes, such as thermal‐chemical process and biochemical process, can be applied to convert lignin into fuel or chemicals. Hydrothermal liquefaction (HTL), a kind of thermal‐chemical conversion technique, uses liquid subcritical or supercritical water as reaction medium for the conversion of biomass and waste streams . In that process, with high‐temperature and high‐pressure water, organic macromolecules are depolymerized into low‐molecular‐weight compounds and monomers, meanwhile some resultant products are still obtained in different phases, namely, gas phase, solid phase, and liquid phase.…”