A process for recovery of lignin from black liquor that contains either soluble or dispersed lignin by generating a “liquid lignin” at high yield is disclosed. Soluble lignin at a high pH is precipitated by reducing the pH of the black liquor stream by countercurrent reaction with carbon dioxide, at elevated temperature and pressure, creating a dense liquid-lignin phase and a light lignin-depleted phase. The dense lignin-rich phase is separated and washed countercurrently with a non-sulfur containing acid, such as acetic acid or formic acid, to displace metal cations from the lignin, creating a low-salt lignin, which is then formed into a low-dust, high-bulk density lignin fuel pellet. If desired, an oxidation step may be used to eliminate odor for lignins having high value green chemistry applications.

The present invention relates to regulation of the p H of a liquefaction process. Presented is a method for treatment of a biomass feedstock wherein the biomass feedstock is subjected to liquefaction, at a p H of at most 4, by treatment with hot compressed liquid water (HCW) at subcritical and/or supercritical conditions to improve the conversion efficiency. The present invention is also directed to quenching of a liquefaction process according to above, preventing, minimizing or eliminating clogging and/or fouling of sticky biomass components in process equipment during processing as according to above, and to the use of additives in a biomass liquefaction process.

The present invention relates to regulation of the p H of a liquefaction process. Presented is a method for treatment of a biomass feedstock wherein the biomass feedstock is subjected to liquefaction, at a p H of at most 4, by treatment with hot compressed liquid water (HCW) at subcritical and/or supercritical conditions to improve the conversion efficiency. The present invention is also directed to quenching of a liquefaction process according to above, preventing, minimizing or eliminating clogging and/or fouling of sticky biomass components in process equipment during processing as according to above, and to the use of additives in a biomass liquefaction process.

Methods of fractionating lignocellulosic biomass using maleic acids are provided. Also provided are methods of forming lignin particles, furans, sugars, and/or lignocellulosic micro- and nanofibrils from the liquid and solid fractions produced by fractionation process. The fractionation can be carried out at low temperatures with short reaction times to carboxylate and dissolve lignin with a low degree of condensation.

Methods of fractionating lignocellulosic biomass using maleic acids are provided. Also provided are methods of forming lignin particles, furans, sugars, and/or lignocellulosic micro- and nanofibrils from the liquid and solid fractions produced by fractionation process. The fractionation can be carried out at low temperatures with short reaction times to carboxylate and dissolve lignin with a low degree of condensation.

A method including: (a) contacting lime with an extract including a S1 solvent carrying a contaminant load to form a lime treated extract; and (b) reducing the contaminant load by removing solids. Optionally, the method includes washing the lime treated extract with water. Optionally, a pH of the lime treated extract is at least 6.5.

A method including: (a) contacting lime with an extract including a S1 solvent carrying a contaminant load to form a lime treated extract; and (b) reducing the contaminant load by removing solids. Optionally, the method includes washing the lime treated extract with water. Optionally, a pH of the lime treated extract is at least 6.5.

Processes disclosed are capable of converting biomass into high-crystallinity nanocellulose with low mechanical energy input. In some variations, the process includes fractionating biomass with sulfur dioxide or a sulfite compound and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin; and mechanically treating the cellulose-rich solids to form nanofibrils and/or nanocrystals. The total mechanical energy may be less than 500 kilowatt-hours per ton. The crystallinity of the nanocellulose material may be 80% or higher, translating into good reinforcing properties for composites. The nanocellulose material may include nanofibrillated cellulose, nanocrystalline cellulose, or both. In some embodiments, the nanocellulose material is hydrophobic via deposition of some lignin onto the cellulose surface. Optionally, sugars derived from amorphous cellulose and hemicellulose may be separately fermented, such as to monomers for various polymers. These polymers may be combined with the nanocellulose to form completely renewable composites.

Processes disclosed are capable of converting biomass into high-crystallinity nanocellulose with low mechanical energy input. In some variations, the process includes fractionating biomass with sulfur dioxide or a sulfite compound and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin; and mechanically treating the cellulose-rich solids to form nanofibrils and/or nanocrystals. The total mechanical energy may be less than 500 kilowatt-hours per ton. The crystallinity of the nanocellulose material may be 80% or higher, translating into good reinforcing properties for composites. The nanocellulose material may include nanofibrillated cellulose, nanocrystalline cellulose, or both. In some embodiments, the nanocellulose material is hydrophobic via deposition of some lignin onto the cellulose surface. Optionally, sugars derived from amorphous cellulose and hemicellulose may be separately fermented, such as to monomers for various polymers. These polymers may be combined with the nanocellulose to form completely renewable composites.

A selective removal of metal and its anion species that are detrimental to subsequent hydrothermal hydrocatalytic conversion from the biomass feed prior to carrying out catalytic hydrogenation/hydrogenolysis/hydrodeoxygenation of the biomass in a manner that does not reduce the effectiveness of the hydrothermal hydrocatalytic treatment while minimizing the amount of water used in the process is provided.