Abstract: In some variations, a process for converting a biomass feedstock into a pretreated biomass material comprises: providing a biomass feedstock containing cellulose, hemicellulose, and lignin; introducing the biomass feedstock and a recycled vapor stream to a biomass-heating unit, thereby generating a heated biomass stream at a first temperature, wherein the recycled vapor stream is at a first pressure of at least atmospheric pressure; feeding the heated biomass stream to a biomass digestor operated at a second temperature and a second pressure to pretreat the biomass feedstock, thereby generating a digested stream comprising a solid-liquid mixture and a digestor vapor, wherein the second temperature is higher than the first temperature, and wherein the second pressure is higher than the first pressure; recycling at least a portion of the digestor vapor to the biomass-heating unit; and recovering or further processing the solid-liquid mixture as a pretreated biomass material. Many variations are disclosed.

Abstract: In some variations, a process for converting a biomass feedstock into a product comprises: providing a biomass feedstock containing cellulose, hemicellulose, and lignin; providing a reaction solution comprising a fluid and optionally a pretreatment chemical; feeding the biomass feedstock and the reaction solution to a biomass digestor operated to pretreat the biomass feedstock, thereby generating a digested stream comprising a solid-liquid mixture and a digestor vapor; discharging the digested stream to a vapor-separation unit operated to separate the digestor vapor from the solid-liquid mixture; optionally recycling at least a portion of the digestor vapor within the process; conveying the solid-liquid mixture, or a portion thereof, to a hydrolysis reactor operated to hydrolyze the cellulose and/or the hemicellulose to monomeric and/or oligomeric sugars; and converting the monomeric and/or oligomeric sugars to a product. Many variations are disclosed.

Abstract: In some variations, a process for preparing a biomass feedstock for conversion to a sugar, a biofuel, a biochemical, or a biomaterial, comprises: providing a biomass feedstock containing cellulose, hemicellulose, and lignin; optionally, introducing the biomass feedstock and a first vapor stream to a biomass-heating unit, thereby generating a heated biomass stream; introducing the biomass feedstock and a first liquid stream to a liquid-addition unit, thereby generating a wet biomass stream, wherein the first liquid stream contains a pretreatment chemical; introducing the wet biomass stream to a mechanical conveyor operated to physically remove liquid from the wet biomass stream, thereby generating an excess-liquid stream comprising the pretreatment chemical and a solid discharge stream comprising the biomass feedstock and the pretreatment chemical; recycling at least a portion of the excess-liquid stream to the first liquid stream; and recovering or further processing the solid discharge stream.

Abstract: A method of enzymatically hydrolyzing pretreated lignocellulosic biomass at high solids concentration includes introducing pretreated biomass to a hydrolysis reactor, to hydrolyze the cellulose to glucose monomer and glucose oligomers, and circulating a liquid stream, from which glucose is removed to reduce glucose inhibition of cellulose hydrolysis. A surfactant may be added to the hydrolysis reactor. Heat and/or acid treatment of the glucose oligomers may be used to generate additional glucose monomer. Some variations introduce pretreated biomass to a hydrolysis reactor to hydrolyze cellulose to glucose monomer and glucose oligomers, followed by conveying a portion of the solid phase to a mechanical refiner and/or a unit under reduced pressure, to generate a refined and/or exploded solid phase; and recycling the refined and/or exploded solid phase, optionally reheated, back to an input of the hydrolysis reactor.

Abstract: Some variations provide a process for impregnating a biomass feedstock with a reaction solution, comprising: providing a biomass feedstock that contains non-condensable gases within biomass pores; introducing a condensable vapor into the biomass pores to remove non-condensable gases out of the biomass pores, thereby generating an intermediate biomass material, wherein at least a portion of the condensable vapor remains within the biomass pores; exposing the intermediate biomass material to a liquid solution to infiltrate the liquid solution into the biomass pores and condense the vapor to form a condensed liquid contained within the biomass pores, thereby generating an impregnated biomass material containing a reaction solution; and recovering or further processing the impregnated biomass material. The non-condensable gases may be oxygen, nitrogen, or carbon dioxide, for example. The condensable vapor may be steam, for example.

Abstract: A method of enzymatically hydrolyzing pretreated lignocellulosic biomass at high solids concentration includes introducing pretreated biomass to a hydrolysis reactor, to hydrolyze the cellulose to glucose monomer and glucose oligomers, and circulating a liquid stream, from which glucose is removed to reduce glucose inhibition of cellulose hydrolysis. A surfactant may be added to the hydrolysis reactor. Heat and/or acid treatment of the glucose oligomers may be used to generate additional glucose monomer. Some variations introduce pretreated biomass to a hydrolysis reactor to hydrolyze cellulose to glucose monomer and glucose oligomers, followed by conveying a portion of the solid phase to a mechanical refiner and/or a unit under reduced pressure, to generate a refined and/or exploded solid phase; and recycling the refined and/or exploded solid phase, optionally reheated, back to an input of the hydrolysis reactor.

Abstract: This invention provides optimized fermentation of cellulosic and hemicellulosic sugars. Biomass-derived hemicellulosic and cellulosic sugars are independently conditioned and separately fermented, utilizing reuse and recycle of microorganisms, metabolic intermediates, and nutrients. Conditioned sugars can be fermented in separate vessels, where excess cells from glucose fermentation are conveyed to hemicellulose sugar fermentation along with raffinate from solvent recovery, to enhance productivity and product yield.

Abstract: This invention provides optimized fermentation of cellulosic and hemicellulosic sugars. Biomass-derived hemicellulosic and cellulosic sugars are independently conditioned and separately fermented, utilizing reuse and recycle of microorganisms, metabolic intermediates, and nutrients. Conditioned sugars can be fermented in separate vessels, where excess cells from glucose fermentation are conveyed to hemicellulose sugar fermentation along with raffinate from solvent recovery, to enhance productivity and product yield.

Abstract: The disclosure provides a process for separating fermentation inhibitors from a biomass-derived hydrolysate, comprising: introducing a biomass-derived liquid hydrolysate stream to a stripping column; introducing a steam-rich vapor stream to the stripping column to strip fermentation inhibitors (such as acetic acid) from the liquid hydrolysate stream; recovering a stripped liquid stream and a stripper vapor output stream; compressing the stripper vapor output stream; introducing the compressed vapor stream, and a water-rich liquid stream, to an evaporator; recovering, from the evaporator, an evaporated liquid stream and an evaporator output vapor stream; and recycling the evaporator output vapor stream to the stripping column as the steam-rich vapor stream. Other variations utilize a rectification column to recover a rectified liquid stream and a rectification column vapor stream, and recycle the rectification column vapor stream to the stripping column as the steam-rich vapor stream.

Abstract: A method of enzymatically hydrolyzing pretreated lignocellulosic biomass at high solids concentration includes introducing pretreated biomass to a hydrolysis reactor, to hydrolyze the cellulose to glucose monomer and glucose oligomers, and circulating a liquid stream, from which glucose is removed to reduce glucose inhibition of cellulose hydrolysis. A surfactant may be added to the hydrolysis reactor. Heat and/or acid treatment of the glucose oligomers may be used to generate additional glucose monomer. Some variations introduce pretreated biomass to a hydrolysis reactor to hydrolyze cellulose to glucose monomer and glucose oligomers, followed by conveying a portion of the solid phase to a mechanical refiner and/or a unit under reduced pressure, to generate a refined and/or exploded solid phase; and recycling the refined and/or exploded solid phase, optionally reheated, back to an input of the hydrolysis reactor.

Abstract: In some variations, this invention provides a process for producing fermentable sugars from cellulosic biomass, comprising: extracting biomass with steam or hot water to produce an extract liquor containing hemicellulose oligomers, dissolved lignin, and cellulose-rich solids; separating and washing the cellulose-rich solids; removing a portion of glucan contained in the washed cellulose-rich solids as glucose oligomers using a liquefaction-focused blend of enzymes; co-hydrolyzing glucose oligomers and hemicellulose oligomers, with enzymes or an acid catalyst, to produce glucose and hemicellulose monomers; and recovering the glucose and hemicellulose monomers as fermentable sugars. The liquefaction-focused blend of enzymes contains endoglucanases and exoglucanases. A rotating unit for high-solids enzymatic hydrolysis may be employed, with continuous liquid removal. Optionally, the glucose and the hemicellulose monomers may be recovered as separate streams.

Abstract: The disclosure provides a process for separating fermentation inhibitors from a biomass-derived hydrolysate, comprising: introducing a biomass-derived liquid hydrolysate stream to a stripping column; introducing a steam-rich vapor stream to the stripping column to strip fermentation inhibitors (such as acetic acid) from the liquid hydrolysate stream; recovering a stripped liquid stream and a stripper vapor output stream; compressing the stripper vapor output stream; introducing the compressed vapor stream, and a water-rich liquid stream, to an evaporator; recovering, from the evaporator, an evaporated liquid stream and an evaporator output vapor stream; and recycling the evaporator output vapor stream to the stripping column as the steam-rich vapor stream. Other variations utilize a rectification column to recover a rectified liquid stream and a rectification column vapor stream, and recycle the rectification column vapor stream to the stripping column as the steam-rich vapor stream.

Abstract: The present invention is capable of producing glucose and hemicellulose sugars from lignocellulosic biomass. In some variations, a process includes optionally pre-steaming a biomass feedstock; extracting the feedstock with liquid hot water to produce glucan-rich solids and an extract liquor containing dissolved solids, which include hemicellulosic oligomers and lignin; washing the glucan-rich solids; hydrolyzing the hemicellulosic oligomers by contacting the extract liquor with an acid catalyst or enzymes possessing hemicellulase activity; separately hydrolyzing the glucan by contacting the glucan-rich solids stream with an acid catalyst or enzymes possessing glucanase activity, optionally with removing the glucose in situ by microfiltration and/or ultrafiltration; and recovering or fermenting each of the hemicellulosic monomers and the glucose. Preferred configurations and conditions are disclosed.

Abstract: In some variations, this invention provides a process for producing fermentable sugars from cellulosic biomass, comprising: extracting biomass with steam or hot water to produce an extract liquor containing hemicellulose oligomers, dissolved lignin, and cellulose-rich solids; separating and washing the cellulose-rich solids; removing a portion of glucan contained in the washed cellulose-rich solids as glucose oligomers using a liquefaction-focused blend of enzymes; co-hydrolyzing glucose oligomers and hemicellulose oligomers, with enzymes or chemical catalyst, to produce glucose and hemicellulose monomers; and recovering the glucose and hemicellulose monomers as fermentable sugars. The liquefaction-focused blend of enzymes contains endoglucanases and exoglucanases. Optionally, the glucose and the hemicellulose monomers may be recovered as separate streams.