Abstract: A process for converting lignocellulosic biomass to fuel, wherein lignocellulosic feedstock is soaked in a sulfuric acid solution to demineralize the feedstock, the demineralized feedstock is pretreated at a temperature between 150° C. and 230° C. and a pH between 1 and 2.5, at least part of the pretreated material is converted to a fermentation production such as ethanol, and at least a portion of a secondary stream, such as still bottoms from the distillation of ethanol, is converted to biogas by anaerobic digestion. Soaking the lignocellulosic feedstock in sulfuric acid solution reduces the amount of sulfuric acid required for the pretreatment, and thus the amount of sulfate carried downstream to the anaerobic digestion. This increases the biogas yield and/or xylose yield. A recycling process, wherein mineralized soaking liquid produced in the soaking process is fed to cation exchange to remove minerals, reduces excess waste of the sulfuric acid and water usage.

Abstract: A process for converting lignocellulosic biomass to glucose or ethanol includes subjecting the lignocellulosic biomass to a SO2 pretreatment within the temperature range 110° C.-150° C. Good glucose yields have been achieved when the SO2 pretreatment is conducted for more than 90 minutes and when the total amount of SO2 available is greater than 20 wt % based on dry weight of lignocellulosic biomass.

Abstract: A process for producing ethanol from lignocellulosic biomass includes adding at least one of sulfur dioxide and sulfurous acid to the lignocellulosic biomass to provide an equivalent sulfur dioxide loading of at least 10 wt % sulfur dioxide to dry lignocellulosic biomass. The acidified lignocellulosic biomass is pretreated at a temperature above about 185° C. and for a pretreatment time less than about 10 minutes, to provide a pretreated biomass composition wherein the biomass is readily hydrolyzed by enzymes. Advantageously, sulfur dioxide from at least one of the flash stream and a stream derived from the flash is recovered and recycled back into the process.

Abstract: A process for converting lignocellulosic biomass to glucose or ethanol includes subjecting the lignocellulosic biomass to a SO2 pretreatment within the temperature range 110° C.-150° C. Good glucose yields have been achieved when the SO2 pretreatment is conducted for more than 90 minutes and when the total amount of SO2 available is greater than 20 wt % based on dry weight of lignocellulosic biomass.

Abstract: A process for producing alcohol from lignocellulosic biomass includes adding at least one of sulfur dioxide and sulfurous acid to the lignocellulosic biomass to provide an effective sulfur dioxide dosage and/or effective sulfur dioxide slurry concentration, each of which is calculated using the ratio of the volume of the slurry in the pretreatment reactor to the total volume of the pretreatment reactor, within a predetermined range.

Abstract: A process for producing alcohol from lignocellulosic biomass includes adding at least one of sulfur dioxide and sulfurous acid to the lignocellulosic biomass to provide an effective sulfur dioxide dosage and/or effective sulfur dioxide slurry concentration, each of which is calculated using the ratio of the volume of the slurry in the pretreatment reactor to the total volume of the pretreatment reactor, within a predetermined range.

Abstract: A process for hydrolyzing a pretreated lignocellulosic feedstock is disclosed herein. The process comprises hydrolyzing the pretreated lignocellulosic feedstock with an enzyme mixture comprising at least cellulase enzymes to produce a hydrolyzed slurry comprising glucose and lignin solids. The hydrolyzing is conducted in the presence of a polymer, such as an aliphatic polyether. A solids-liquid separation is conducted to recover lignin solids from a process stream comprising the lignin solids and the polymer. A process stream is then obtained comprising recovered lignin solids resulting from the solids-liquid separation. Also provided are processes for recovering the polymer from the lignin solids and/or from solution.

Abstract: A process for producing ethanol from lignocellulosic biomass includes adding at least one of sulfur dioxide and sulfurous acid to the lignocellulosic biomass to provide an equivalent sulfur dioxide loading of at least 10 wt % sulfur dioxide to dry lignocellulosic biomass. The acidified lignocellulosic biomass is pretreated at a temperature above about 185° C. and for a pretreatment time less than about 10 minutes, to provide a pretreated biomass composition wherein the biomass is readily hydrolyzed by enzymes. Advantageously, sulfur dioxide from at least one of the flash stream and a stream derived from the flash is recovered and recycled back into the process.

Abstract: The present invention relates to a process for hydrolyzing a pretreated lignocellulosic feedstock. The process comprises hydrolyzing the pretreated lignocellulosic feedstock with an enzyme mixture comprising at least cellulase enzymes to produce a hydrolyzed slurry comprising glucose and lignin solids. The hydrolyzing is conducted in the presence of a polymer, such as for example an aliphatic polyether. A solids-liquid separation is conducted to recover lignin solids from a process stream comprising the lignin solids and the polymer. A process stream is then obtained comprising recovered lignin solids resulting from the solids-liquid separation. Also provided are processes for recovering the polymer from the lignin solids and/or from solution.