Methods and systems for preparing agricultural residue or other agricultural feedstock for use as a pulp. The method includes providing non-wood agricultural residue (e.g., corn stover) or other agricultural feedstock that includes agricultural fibers, chemically pulping the agricultural fibers in a preliminary alkaline chemical pulping process at a low consistency and at a low temperature to produce partially pulped agricultural fibers, such step including separating lignin and hemicellulose from the partially pulped agricultural fibers, introducing the partially pulped agricultural fibers into a first reactor, wherein the first reactor operates at a low temperature of less than 100° C. (e.g., 65° C.), introducing the agricultural fibers from the first reactor into a second reactor, where the second reactor operates at a low temperature, of less than 100° C. (e.g., 94-96° C.), the second reactor operating at a higher temperature than the first reactor, to produce pulped agricultural fibers.

The present disclosure generally relates to a method for controlled pretreatment of lignocellulosic biomass. The method comprises the steps of: Pretreating (S10) a lignocellulosic biomass material in a pretreatment arrangement, the pretreating comprising impregnating (S10A) the lignocellulosic biomass with an SO2 feed in an impregnation vessel of the pretreatment arrangement; collecting (S20) a number of process parameters of the pretreatment, which process parameters include at least a feed parameter related to the total amount of lignocellulosic biomass input to the pretreatment arrangement, and a dry matter parameter related to the dry matter content of lignocellulosic biomass input to the pretreatment arrangement; and adjusting (S30) the SO2 feed in response to the process parameters.

A system for treatment of a biomass material, said system comprising: a first vessel (3) in which said biomass material is treated under a first pressure; a second vessel (5) in which said biomass material is received and held at a second pressure which is lower than the first pressure; a transporting pipe (7) connecting an outlet (9) of the first vessel (3) with an inlet (11) of the second vessel (5) for transporting the biomass material from the first vessel to the second vessel; and a valve (15; 15′; 15) arranged in said transporting pipe (7), said valve being configured for controlling the flow of biomass material and fluid in the transporting pipe (7), wherein said transporting pipe (7) is asymmetrically connected to an outlet (33′; 33) of said valve (15; 15′; 15) such that a generated jet stream of biomass material delivered out from the outlet (33′; 33) of the valve (15; 15′; 15) is received closer to a transporting pipe longitudinal central axis (A1) than if the outlet (33′; 33) of the valve (15; 15′; 15) and the transporting pipe (7) would have been connected symmetrically.

Method for controlled delignification of lignocellulosic feedstock, said method comprising the steps of: providing a reactive phase of pH less than 1, said reactive phase comprising: water; sulfuric acid; a source of peroxide; a modifying agent, said modifying agent adapted to control the reactivity of the sulfuric acid; providing a holding phase, said holding phase comprising an organic solvent which does not react with the aqueous acidic composition; combining said reactive phase and holding phase to form a reaction mixture; exposing a lignocellulosic material to said reaction mixture for a period of time sufficient to allow delignification of the lignocellulosic material.

Method for controlled delignification of lignocellulosic feedstock, said method comprising the steps of: providing a reactive phase of pH less than 1, said reactive phase comprising: water; sulfuric acid; a source of peroxide; a modifying agent, said modifying agent adapted to control the reactivity of the sulfuric acid; providing a holding phase, said holding phase comprising an organic solvent which does not react with the aqueous acidic composition; combining said reactive phase and holding phase to form a reaction mixture; exposing a lignocellulosic material to said reaction mixture for a period of time sufficient to allow delignification of the lignocellulosic material.

The present invention provides a pulp product (e.g., paper) comprising cellulose and nanocellulose, wherein the nanocellulose is derived from the cellulose in a mechanical and/or chemical step that is separate from the main pulping process. The pulping process may be thermomechanical pulping or hydrothermal-mechanical pulping, for example. The pulp product is stronger and smoother with the presence of the nanocellulose. The nanocellulose further can function as a retention aid, for a step of forming the pulp product (e.g., in a paper machine). Other embodiments provide a corrugated medium pulp composition comprising cellulose pulp and nanocellulose, wherein the nanocellulose includes cellulose nanofibrils and/or cellulose nanocrystals and the nanocellulose may be hydrophobic. The nanocellulose improves the strength properties of the corrugated medium. In some embodiments, the cellulose pulp is a GreenBox+® pulp and the nanocellulose is derived from the AVAP® process.

The invention relates to the chemical industry, namely to the production method of cellulose from all types of plant cellulose-containing raw material. The method includes raw material impregnation and hydrolysis in a hydrolysis solution, cellulose filtration, washing with water, filtration and drying, accompanied with the use of cycles that include heating of the material to a temperature of 115° C. or less, high-speed impulse action of vacuum with a pressure change in the range up to 5 mm Hg for a time of less than 10 seconds, followed by exposure under vacuum and vacuum relief.

Both solution of nitric or sulphuric acids, their mixture and alkaline solution can be used as hydrolysis solution.

Technical result of the claimed method consists in. reducing the duration of the cellulose hydrolysis process, reducing the temperature of the processes while obtaining the required chemical and structural homogeneity of the cellulose.

The present invention addresses the problem of efficiently manufacturing a recycled pulp from a used sanitary article, said recycled pulp being reusable for sanitary articles and having an ash content and antibacterial properties both meeting the standards for sanitary articles. A method for manufacturing a recycled pulp reusable for sanitary articles by recovering a pulp fiber from a used sanitary article that contains the pulp fiber and a high water-absorbing polymer, said method comprising an ozone treatment step for immersing the used sanitary article or pulp fiber in an ozone-containing aqueous solution and thus disintegrating the high water-absorbing polymer contained in the used sanitary article or sticking to the pulp fiber, characterized in that the used sanitary article or pulp fiber is treated with a cationic antibacterial agent before, after or together with the ozone treatment step.

The present invention addresses the problem of efficiently manufacturing a recycled pulp from a used sanitary article, said recycled pulp being reusable for sanitary articles and having an ash content and antibacterial properties both meeting the standards for sanitary articles. A method for manufacturing a recycled pulp reusable for sanitary articles by recovering a pulp fiber from a used sanitary article that contains the pulp fiber and a high water-absorbing polymer, said method comprising an ozone treatment step for immersing the used sanitary article or pulp fiber in an ozone-containing aqueous solution and thus disintegrating the high water-absorbing polymer contained in the used sanitary article or sticking to the pulp fiber, characterized in that the used sanitary article or pulp fiber is treated with a cationic antibacterial agent before, after or together with the ozone treatment step.

A process for recovery of lignin from black liquor that contains either soluble or dispersed lignin by generating a “liquid lignin” at high yield is disclosed. Soluble lignin at a high pH is precipitated by reducing the pH of the black liquor stream by countercurrent reaction with carbon dioxide, at elevated temperature and pressure, creating a dense liquid-lignin phase and a light lignin-depleted phase. The dense lignin-rich phase is separated and washed countercurrently with a non-sulfur containing acid, such as acetic acid or formic acid, to displace metal cations from the lignin, creating a low-salt lignin, which is then formed into a low-dust, high-bulk density lignin fuel pellet. If desired, an oxidation step may be used to eliminate odor for lignins having high value green chemistry applications.