The invention relates, in general, to methods of processing Lignocellulosic biomass to fermentable sugars and to methods that rely on hydrothermal pretreatment. Xylose monomer yields comparable to those achieved using two-stage pretreatments can be achieved from soft Lignocellulosic biomass feedstocks by pretreasting to very low severity in a single-stage pressurized hydrothermal pretreatment, followed by enzymatic hydrolysis to release xylose retained in the solid state. In some embodiments, pretreated biomass is separated into a solid fraction and a liquid fraction, the solid fraction subjected to enzymatic hydrolysis, and the separated liquid fraction subsequently mixed with the hydrolysed solid fraction.

The APPARATUSES, METHODS AND SYSTEMS FOR APPARATUSES, METHODS AND SYSTEMS FOR YIELD INCREASE IN A KRAFT COOKING PLANT present synergies for at least two parallel cooking plants, e.g., one producing dissolving pulp in a prehydrolysis kraft process, and the other producing kraft pulp by kraft pulping process, which may facilitate increased cooking yield in the kraft cooking plant producing kraft pulp by recovering the hemicelluloses solubilized in the acidic hydrolysate of the prehydrolysis kraft process. In some implementations, there may be no cold caustic extraction step on the dissolving pulp line as the target pulp purity can be achieved by performing just a prehydrolysis step, with reutilization of an acidic hydrolysate stream in a kraft pulp line.

The APPARATUSES, METHODS AND SYSTEMS FOR APPARATUSES, METHODS AND SYSTEMS FOR YIELD INCREASE IN A KRAFT COOKING PLANT present synergies for at least two parallel cooking plants, e.g., one producing dissolving pulp in a prehydrolysis kraft process, and the other producing kraft pulp by kraft pulping process, which may facilitate increased cooking yield in the kraft cooking plant producing kraft pulp by recovering the hemicelluloses solubilized in the acidic hydrolysate of the prehydrolysis kraft process. In some implementations, there may be no cold caustic extraction step on the dissolving pulp line as the target pulp purity can be achieved by performing just a prehydrolysis step, with reutilization of an acidic hydrolysate stream in a kraft pulp line.

A reactor arrangement for pre-hydrolysis of biomass material. The reactor arrangement comprises a reactor vessel arranged substantially horizontally, wherein the vessel comprises an inlet for receiving the biomass material arranged at an upper portion of the vessel. The inlet may be arranged at a first longitudinal end of the vessel. The vessel may furthermore comprise an outlet at a second longitudinal end of the vessel. The reactor arrangement further comprises a set of steam injection orifices arranged to inject or supply steam into the reactor vessel. The set of steam injection orifices comprises at least two orifices arranged below the inlet at a distance from each other. The at least two orifices may be arranged at a distance from each other in the lateral direction of the reactor vessel. Furthermore, a method for pre-hydrolysis treatment of biomass in a substantially horizontal reactor vessel is provided.

An aqueous composition comprising: sulfuric acid; a modifying agent comprising an amine group; and a peroxide. Said composition being capable of delignifying biomass under milder conditions than conditions under which kraft pulping takes place.

An aqueous composition comprising: sulfuric acid; a modifying agent comprising an arylsulfonic acid; and a peroxide. Said composition being capable of delignifying biomass under milder conditions than conditions under which kraft pulping takes place.

An aqueous composition comprising: sulfuric acid; a modifying agent comprising a carbonyl-containing nitrogenous base compound; and a peroxide. Said composition being capable of delignifying biomass under milder conditions than conditions under which kraft pulping takes place.

An aqueous composition comprising: sulfuric acid; a heterocyclic compound; and a peroxide. Said composition being capable of delignifying biomass under milder conditions than conditions under which kraft pulping takes place.

A process for converting lignocellulosic biomass to glucose or ethanol includes subjecting the lignocellulosic biomass to a SO.sub.2 pretreatment within the temperature range 110° C.-150° C. Good glucose yields have been achieved when the SO.sub.2 pretreatment is conducted for more than 90 minutes and when the total amount of SO.sub.2 available is greater than 20 wt % based on dry weight of lignocellulosic biomass.

A process for converting lignocellulosic biomass to glucose or ethanol includes subjecting the lignocellulosic biomass to a SO.sub.2 pretreatment within the temperature range 110° C.-150° C. Good glucose yields have been achieved when the SO.sub.2 pretreatment is conducted for more than 90 minutes and when the total amount of SO.sub.2 available is greater than 20 wt % based on dry weight of lignocellulosic biomass.