Abstract: A continuous process for producing hemicellulose sugars from a biomass extraction liquor is provided. A system is configured for continuously producing hemicellulose sugars and/or hemicellulose derivatives from a biomass extraction liquor, the system comprising at least a first hydrolysis reactor and a second hydrolysis reactor. Each of the hydrolysis reactors is in switchable communication with (i) an operating feed stream of a biomass extraction liquor containing water, hemicellulose oligomers, and dissolved or suspended lignin, and (ii) a cleaning feed stream of a cleaning agent selected from the group consisting of steam, an alkaline solution, an organic solvent, and combinations thereof. The cleaning agent dissolves precipitated lignin formed from the lignin under the hydrolysis reaction conditions.

Abstract: The present invention provides, among other things, methods including providing a biomass comprising lignin, associating the biomass with between 1-50 g/L formic acid at a temperature between 80° C. and 230° C. for at least 30 seconds to form an extraction liquor and an extraction solid, and separating at least a fraction of the extraction liquor from the extraction solid, wherein an amount of lignin equal to or less than 1.6% of the lignin present in the biomass precipitates in the extraction liquor after cooling to below 100° C.

Abstract: The invention provides a method for purifying a biomass hydrolysate comprising sugars and suspended particles, comprising centrifuging the biomass hydrolysate, thermally treating the centrifuged hydrolysate to chemically or physically agglomerate the suspended particles, and filtering the thermally treated hydrolysate to remove agglomerated suspended particles, thereby generating a purified hydrolysate (sugar syrup). The sequence of steps may be varied. Biomass hydrolysates may be provided from a wide variety of processes. Surprisingly, a 20-fold improvement in sugar purity (total suspended solids content) is demonstrated experimentally, compared to prior methods.

Abstract: A continuous process for producing hemicellulose sugars from a biomass extraction liquor is provided. A system is configured for continuously producing hemicellulose sugars and/or hemicellulose derivatives from a biomass extraction liquor, the system comprising at least a first hydrolysis reactor and a second hydrolysis reactor. Each of the hydrolysis reactors is in switchable communication with (i) an operating feed stream of a biomass extraction liquor containing water, hemicellulose oligomers, and dissolved or suspended lignin, and (ii) a cleaning feed stream of a cleaning agent selected from the group consisting of steam, an alkaline solution, an organic solvent, and combinations thereof. The cleaning agent dissolves precipitated lignin formed from the lignin under the hydrolysis reaction conditions.

Abstract: A process is provided for producing a lignin-coated cellulose material, comprising: pre-extracting a lignocellulosic biomass feedstock in the presence of steam or hot water, depositing lignin from the liquid onto a surface of solids to generate a lignin-coated intermediate material; optionally drying the intermediate material; digesting the lignin-coated intermediate material in the presence of an acid, a solvent for lignin, and water, wherein the rate of delignification of surface lignin is lower than the rate of delignification of bulk lignin; and recovering a hydrophobic lignin-coated cellulose material. In some variations, part of the overall process is a combination of Green Power+® and AVAP® technologies. A cellulose-rich composition is provided, containing about 5 wt % to about 15 wt % total lignin, with particles having a higher average surface concentration of lignin compared to an average bulk (internal) concentration of lignin.

Abstract: The present invention provides a process for fractionating lignocellulosic biomass, comprising: digesting a biomass feedstock in the presence of a solvent for lignin, an acid, and water, to produce cellulose-rich solids; separating and washing the cellulose-rich solids with a wash solvent; washing the cellulose-rich solids with water, to generate washed cellulose-rich solids and a wash liquor comprising fines, wherein the wash liquor is introduced to or in contact with a classifier to remove the fines; and separating the fines and recycling the remaining water. The classifier may include a screen with mesh size in the range of 10 to 500, such as 200. The washed cellulose-rich solids will typically have a lower Kappa number (lignin content) and ash content compared to cellulose-rich solids from a process without a classifier that removes fines.