A process for processing lignocellulosic biomass that includes pretreating lignocellulosic biomass, wherein the lignocellulosic biomass is heated in a pretreatment liquor containing sulfur dioxide and bisulfite salt, at a temperature between 120° C. and 150° C., for at least 30 minutes. The pH of the pretreatment liquor at 25° C. is less than 1.3, the concentration of sulfur dioxide is greater than 9.4 wt % (on liquor), and the concentration of alkali is between 0 wt % and 0.42 wt % (expressed as hydroxide, on liquor).

The present invention concerns a method for carrying out the combined operation of a bioethanol production unit and a biogas unit. The method comprises the following steps: a) mashing corn meal from a dry milling step with at least 0.1 t of dry matter in the form of whole stillage and at least 0.1 m.sup.3 of outflow from the biogas unit per tonne of corn meal, b) feeding the mash from a) to a cooking stage with mash temperatures below the gelatinization temperature of the starch inn the corn meal, followed by an ethanol-forming fermentation step and then feeding the fermented mash to a distillation step, c) feeding the whole stillage from b) to the mashing step in a) and to the biogas unit.

Improved processes and systems for recovering products from a corn fermentation mash. In some examples, a process recovers an oil product, a protein meal product, and a fiber product from a slurry. A process includes the following steps: introducing the slurry into a device with a flexible screen and mechanical agitation to produce a filtrate and a fibrous solid stream; and introducing the filtrate into a three-phase centrifuge to produce an oil stream, a high protein solids stream, and a water with solubles stream. The flexible screen includes a washing nozzle. The slurry is whole stillage from an ethanol process. The three-phase centrifuge is a three-phase decanter. The filtrate is heated before introducing into the three-phase centrifuge. The filtrate is optionally evaporated before introducing into the three-phase centrifuge.

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.

Disclosed herein are methods, systems, and compositions for the pretreatment of biomass within seconds with low inhibitor formation. The pretreatment process is used to convert biomass to a fuel or other useful chemicals by subjecting the feedstock to a rapid retention time under pressure and temperature and/or chemical reactant. The system includes a continuously-operating valve discharge apparatus to discharge pretreated feedstock while maintaining uniform pressure on the pretreatment system.

The present invention provides a method of improving a biomass high-solid enzymatic hydrolysis rate. By screening particle sizes of the biomass substrate, different water content controls are performed on coarse and fine particle biomass substrates and then an entire water content of the mixture of the coarse and fine particle biomass substrates is controlled to achieve a reduced initial viscosity of the enzymatic hydrolysis and improve liquefaction speed, and finally improve the biomass high-solid enzymatic hydrolysis rate. The enzymatic hydrolysis system of the present invention can be easily constructed with lower equipment requirements, lower energy consumption, higher enzymatic hydrolysis efficiency and simpler operation process, helping the industrial production and applications.

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. Many variations are disclosed.

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.

A process to hydrolyze cellulose into cellobiose comprising the following steps: providing a reaction vessel; providing a Cellulomonas uda (ATCC 491) inoculum; exposing said Cellulomonas uda (ATCC 491) bacterium to a source of cellulose having a kappa number of less than 10 in an aqueous medium of pH of about 8 at a temperature ranging from 30° C. to 35° C. for a period of time ranging from 14 to 42 days; exposing the cellobiose to a bacterium or fungi or yeast, or combination which converts cellobiose to glucose or ethanol.

The present disclosure relates to processes for producing hydrocarbon fuels from lignocellulosic biomass. A process may include introducing biomass to a pretreatment system, and a first separation system forming a pentose-rich stream and a pentose-lean stream. The pentose-lean stream may be introduced to a hydrolysis system forming a hydrolysate and the hydrolysate introduced to a second separation system forming a hexose-rich stream and a lignin stream. Additionally, at least one of the pentose-rich stream or the hexose-rich stream may be introduced to a bioreactor containing microorganisms configured to produce hydrocarbon fuels. Additionally, the present disclosure also relates to systems for the production of hydrocarbon fuels. A system may include a pretreatment system, a first separation system, a hydrolysis system, a second separation system, and one or more bioreactors. Alternatively a system may include a pretreatment system, a hydrolysis system, a sugar separation system, and one or more bioreactors.