Effect of biomass pretreatment on the product distribution and composition resulting from the hydrothermal liquefaction of short rotation coppice willow

Abstract

A major challenge for the implementation of hydrothermal liquefaction (HTL) as a continuous process is the formulation of lignocellulosic feedstock, which is prone to phase separation into water and biomass parts when pressurized. One approach to remedy such phase separation is to reduce the dry matter content; however, as this approach is detrimental to process cost efficiency, designing an appropriate pretreatment step to ensure pumpability at high dry matter content is preferable. This paper evaluated the effect of various pretreatment methods on product distribution and composition resulting from the HTL of willow and proposes short rotation coppice as an alternative biomass feedstock for biofuels production. Alkaline-thermal pretreatment, besides making high dry matter pumpable feedstock slurries, also led to an increase in the production of the bio-crude product with an oxygen content lower than 8wt% and a higher concentration of aromatics and phenolic compounds.

Lignocellulosic Ethanol Biorefinery: Valorization of Lignin-Rich Stream through Hydrothermal Liquefaction

“…The multi-step solvent extraction method was applied by many authors [14,21,30,[42][43][44][45][46][47]. Usually, the first solvent needs to be immiscible in water in order to be easily separated from the aqueous phase.…”

“…The former two were chosen for dissolving the lighter organic compounds since they are polar and slightly miscible in water; while acetone was selected for the heavier fraction dissolution. DEE and DCM have been used for the biocrude extraction in many works, some examples are reported in Reference [14,30,43] and References [44][45][46][47] respectively. As extraction solvent for the heavy biocrude, DMK was chosen only on literature guidelines [21,42,46], as BC2 is composed of complex high-molecular aromatic oxygenated polymers, which are not possible to be characterized with the same analytical techniques applied on the light biocrude and due to its low toxicity.…”

Catalytic valorization of lignocellulosics: from bulk biofuels to value‐added chemicals

“…Furthermore, different treatment steps can be used to tune the properties of biochar during or after the hydrothermal carbonization process. Metal‐hydrochar prepared by the one‐step hydrothermal carbonization of biomass is rich in various oxygenated functional groups (e.g., hydroxyl, carbonyl, carboxyl, and lactone), 130–132 which could enhance the carbon‐metal precursor interaction and may contribute to better catalytic ability for the biomass hydrolysis process.…”

Cellulose enzymatic saccharification and preparation of 5-hydroxymethylfurfural based on bamboo hydrolysis residue separation in ionic liquids

“…There are many pretreatment methods for biomass separation, like acid treatment, alkali treatment, organic solvents method and steam explosion, but all of them have obvious shortcomings, such as polluting the environment and high energy consumption. [7][8][9][10] Therefore, developing a new method is the priority among priorities. Ionic liquids (ILs) provide a new method for biomass pretreatment.…”