Abstract: The present invention aims firstly to provide a novel technique capable of preparing bleached pulp having high brightness from materials having low bleachability containing high levels of extractives and secondly to provide a technique capable of reducing the amount of bleaching agents used in processes for preparing bleached mechanical pulps.

Abstract: The invention relates to a method of preparing chemical pulp and xylose by the use of alkaline or neutral cooking and post hydrolysis of the pulp by performing the post hydrolysis directly on the pulp by means of acid treatment. In the method of the invention, the xylan in the pulp is utilized as completely as possible, resulting in a good xylose yield and, simultaneously, acceptable characteristics for the pulp.

Abstract: The present invention relates to a method for end-bleaching of pulp containing metal ions after a sequence comprising alkaline bleaching stages only and optionally treatment with complex forming agent, wherein the end-bleaching comprises two chlorine dioxide stages at a pulp concentration of 8-20% and pH 2.5-4.5 wherein the pulp after the first chlorine dioxide stage is washed and dewatered to a concentration of 12-50% for removal of the out-dissolved metal ions and that alkali thereupon is added to the pulp for fast alkali extraction and increase of pH to 8-14, whereupon the pulp is provided with acid and chlorine dioxide and introduced into the second chlorine dioxide stage.

Abstract: The present invention discloses methods of bleaching chemical pulp that combine xylanase enzymes with hydrogen peroxide, peracids, or a mixture. The method comprises the steps of carrying out a chemical pulping operation, optionally followed by delignifying the pulp with oxygen, then combining xylanase enzymes with hydrogen peroxide, peracids, or a mixture to bleach the pulp. The method allows the mill to use both xylanase and peracids in a single bleaching tower to decrease the usage of chlorine dioxide and other bleaching chemicals. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.

Abstract: The present invention relates to a method of pretreating, by acidification and chelation, of pulp to be bleached with peroxide. Especially, the invention relates to intensifying, and at the same time simplifying the pretreatment required by peroxide bleaching. It is characteristic of the invention to introduce pulp into an acid tower (14, 112) where the pressure is 0 to 20 bar, preferably 1 to 10 bar, and the temperature 75 to 130° C. preferably 80 to 110° C., to treat the pulp in acid tower (14, 112) at a pH of 2 to 6, preferably 3 to 4, for 20 to 240 minutes, for decreasing the kappa number by 1-9, preferably 2-6 kappa units, to transfer the pulp from acid tower (14, 112) to a tower (24) of a second treatment stage, to treat the pulp with either a complexing agent at a pH of 4 to 9, preferably 5 to 6, or with an oxidizing chemical such as chlorine dioxide, Caro's acid, peracids or equivalent, and to wash and/or press the pulp.

Abstract: A process for producing microcrystalline cellulose comprised of the steps of contacting a paper grade pulp with an alkali hydrolysis agent, washing the hydrolyzed pulp and contacting the hydrolyzed pulp with an acid hydrolysis agent and washing the acid hydrolyzed product.

Abstract: A process for the preparation of concentrated solutions or suspensions of anionic organic compounds is described, which process comprises a) acidifying an aqueous solution or dispersion of an anionic organic compound that comprises salts and/or impurities to a pH of 4.5 or less, if the pH is above that value, so that the anionic organic compound becomes insoluble in water and precipitates out in the form of the free acid, b) bringing the suspension obtained from the previous step to a salt content below 2% by weight, based on the total weight of retentate, by means of ultra-filtration with a ceramic membrane or an acid-resistant organic membrane having a pore size of from 1 to 20 nm, and c) optionally washing out of the salts with water at a pH of less than 4.

Abstract: Paper is formed from typically cellulose fibres which have a tendency to become discoloured during processing. Thus, in order to provide good quality white paper, it is necessary to bleach that paper to limit biological activity and remove discolouration. Of concern with respect to this particular invention is also the requirement to add so-called optical brightness agents (OBA). These optical brightness agents essentially fluoresce in daylight in order to give the impression of pure white colour even though the underlying fibres are still yellow white after bleaching. Optical brightness agents are expensive and therefore the present invention provides a composition which reduces the proportion of OBA agent necessary to achieve desired base point increases in paper quality.

Abstract: The invention relates to methods for reducing the amount of halogenated organics produced during a halogen bleaching process for lignocellulosic pulp fibers. According to the disclosed invention, it has been discovered that the use of a chelating agent prior to a non-halogen containing bleaching stage of a pulp bleaching process is effective to increase the brightness of the resulting bleached pulp without the need to increase the amount of halogen compounds required to obtain the same pulp brightness and without adversely affecting the pulp viscosity and yield.

Abstract: A method to enhance brightness in Chemical and Mechanical bleached pulps comprising adding an organic sulfide chelant to the Chemical and Mechanical pulp.

Abstract: Various types of paper pulp are bleached in two steps at atmospheric pressure and at a temperature of less than or equal to 100° C. The first step is carried out by bringing the raw pulp into contact with a mixture of peracetic acid and performic acid. The second step is carried out by treating the bleached pulp obtained from the first step, with a solution of sodium hydroxide and hydrogen peroxide. The pulps obtained have a high brightness value and a degree of polymerization close to the raw pulps. The method is ecological and nonpolluting.

Abstract: This invention is a method of reducing the resin content of chemical pulps comprising heating wood chips in an aqueous alkaline medium in the presence of an effective deresinating amount of an alkyl alcohol alkoxylate of formula RO[(CH2CHCH3O)x(CH2CH2O)y]M wherein R is C4 to C40 alkyl; x is 1-50; y is 0-100 and M is H or an alkali metal, a cooking liquor comprising sodium hydroxide and sodium sulfite and the alkyl alcohol alkoxylate and a deresinated pulp prepared according to the method.

Abstract: This invention relates to a process of treating a lignocellulosic material to produce bio-ethanol. The process includes the steps of: (a) exposing the ligno-cellulosic material to conditions including a pH not less than about 8, and steam at a first pressure, to produce a step (a) product; (b) explosively discharging the step (a) product to a second pressure less than the first pressure-to produce a step (b) product; and (c) further processing the step (b) product to produce bio-ethanol and other co-products. In another embodiment, the invention relates to a conical auger fractionation column. The fractionation column includes a column body having an input and an output. A conical filter is positioned inside the column body, the filter having a larger diameter end directed toward the input and a smaller diameter end directed toward the output.

Abstract: A process for the bleaching of lignin present in pulp fibers in an aqueous environment such as a pulp suspension. The invention also relates to a process for producing paper or board from pulp containing bleached lignin. According to the invention carbon dioxide is used for the bleaching of lignin.

Abstract: A method is provided for deinking paper. Repulped paper is treated with a deinking comprising a triglyceride. A preferred triglyceride is beef tallow. The deinking composition reduces foaming and increases brightness.

Abstract: Compositions and method for improving properties of pulp produced or reducing the digester cycle time in alkaline chemical pulping processes in which an effective amount of at least one selected phosphonate or carboxylate compound or mixtures thereof is admixed with the alkaline aqueous mixture in the digester of the chemical pulping process. The compositions and method are especially well suited for use in the Kraft pulping process.

Abstract: A method of producing a high quality paper pulp slurry from high silica content lignocellulosic agricultural waste materials is provided. The method includes combining the agricultural waste materials with a chemical composition to form a mixture, sautéing the mixture, and grinding the sautéed mixture to provide the pulp slurry. The method results in greater than 55 percent solids recovery in the pulp slurry relative to the starting lignocellulosic agricultural waste materials, and removes substantially none of the lignin from the agricultural waste materials.

Abstract: The invention relates to a process for digesting woodchips used in papermaking. The process employs a digester additive, which is a mixture of (a) a polyglycoside, and (b) a polyoxyalkylene glycol. The digester additives are compatible and stable at elevated temperatures in the highly alkaline white liquor used in the digestion of wood chips into pulp. The invention also relates to the digester additive compositions.

Abstract: A process for bleaching high bulk cellulosic fiber and producing a durable elevated curl index includes: (a) concurrently bleaching, heat treating and convolving cellulosic fiber pulp at elevated temperature and pressure at high consistency generally under conditions selected so as to preclude substantial fibrillation and attendant paper strength and fiber bonding development; and (b) recovering the pulp wherein the length weighted curl index of the treated fiber is at least about 20% higher than the length weighted curl index of the fiber prior to the heat treatment and convolving thereof. Preferably, the curl imparted to the fiber persists upon treatment for 30 minutes in a laboratory disintegrator at 3000 rpm at 1% consistency at a temperature of 125° F. Moreover, the curl may be imparted to the fiber in a disk refiner at very short residence times, on the order of several seconds or less.

Abstract: Method for enabling the paper pulp production process to be controlled in such a way that the hexenuronic acid content in the pulp can be minimized and the colour reversion of the pulp and/or the pulp products thereby minimized. The method is based on measurements of the optical properties of a fibre-containing substance or process stream in the wave length region 232±5 nm and another wavelength interval. A significant value for the current hexenuronic acid content is formed by correcting the intensity in the spectrum around 232 by the corresponding optical quantity at the other wavelength interval. The content of the hexenuronic acid content which is determined by the analysis is then used for controlling conditions in the process stage.

Abstract: A process for bleaching substantially lignin-free pulp or paper in a single-stage bleaching process or multi-stage bleaching process; comprising

Abstract: A method and device for bleaching chemical paper pulp or dissolving wood pulp, which has been cooked and delignified without employing chlorine-containing chemicals, comprising a bleaching sequence which comprises optionally a first stage comprising a chelation treatment step; a second stage comprising a first peroxide treatment stage, wherein said first peroxide treatment stage is a delignifying peroxide treatment stage in which the amount of peroxide is less than 12 kilo/bone dry metric tons; a third stage comprising an acidic delignifying treatment stage, following said second stage and including a wash, and a fourth stage comprising a second peroxide treatment stage, following said third stage and including a wash, wherein said second peroxide treatment stage is a bleaching peroxide treatment, in which the amount of peroxide exceeds 3 kilo/bone dry metric tons and exceeds the amount of peroxide employed in said second step.

Abstract: The invention relates to a process for treating bleaching liquors from pulping processes based on organic acids. The process is characterized in that inorganic acid such as nitric acid, phosphoric acid and/or sulphuric acid, is added into a bleaching liquor obtained from the bleaching or a stage closely associated with bleaching, whereby organic acids contained in the bleaching liquor are released into the bleaching liquor. The organic acids are then separated from the bleaching liquor and recycled to the cooking stage to be used as cooking chemicals. The nitrogen-, phosphor- and/or sulphur-containing product thereby produced, from which organic acids have been separated, is recovered to be used as a fertilizer or as raw material for a fertilizer.

Abstract: In one embodiment of the invention is disclosed a process for the production of microcrystalline cellulose comprising

Abstract: Wood and non-wood pulp is bleached by: a) adding an aliquot of agglomerate from a bulk solids dispensing means, advantageously a hopper, to a dilute solution of hydrogen peroxide which is desirably agitated to keep the agglomerate in suspension, the agglomerate comprising: a bleach activator, advantageously tetraacetyl ethylene diamine (TAED); a peroxide soluble binder, preferably polyvinyl alcohol (PVOH); a dispersing system comprising a wetting agent which is a low foaming and does not discolour on exposure to temperatures of up to 120° C. and optionally a salt, preferably sodium acetate, which is highly soluble in hydrogen peroxide; and sequestrant which may additionally or alternatively be added directly to the hydrogen peroxide; b) allowing the TAED to substantially completely react with the hydrogen peroxide; c) adjusting the pH of the bleach solution by adding alkali, preferably caustic soda; and d) bleaching the pulp by contacting it with the bleaching solution under alkaline conditions.

Abstract: A two-component mediator system is disclosed, wherein one component serves as a pro-oxidant and the other component serves as a pro-degradant and booster. When used in combination with a laccase, the two-component mediators enhance the bleaching of pulp. In addition, a composition comprising an oxidative enzyme, a pro-oxidant, and a pro-degradant, and a process for oxidizing a substrate that comprises treating the substrate with an oxidizing enzyme, a pro-oxidant, and a pro-degradant are disclosed. The pro-oxidant can be ascorbic acid, ascorbate, salicylic acid, salicylate, nicotinic acid, nicotinate, a hardwood black liquor, a softwood black liquor, ligno-organosolv, lignin sulfonate, or mixtures thereof. The pro-degradant can be urea, thiourea, sulfamic acid, sulfamide, guanidine, methylsulfonic acid, or mixtures thereof.

Abstract: Pulping liquors used in the bleaching of pulps by hydrogen peroxide, and containing catalase-producing bacteria and/or catalase enzyme are treated with tris (hydroxymethyl) phosphine or a tetrakis (hydroxymethyl) phosphonium salt to kill the bacteria and destroy the enzyme.

Abstract: A composition comprising an enzyme exhibiting laccase activity and an enzyme enhancing agent, also referred to as a mediator, is disclosed. A process for oxidizing a substrate that comprises treating the substrate with a composition comprising an enzyme exhibiting laccase activity and an enzyme enhancing agent is disclosed. The process when used on lignin-containing material bleaches the lignin-containing material. A process for enhancing the activity of an enzyme exhibiting laccase activity that comprises adding an enzyme enhancing agent to the enzyme is also disclosed.

Abstract: A process based on formic acid cooking for producing pulp from herbaceous plants and deciduous trees by using acetic acid as an additional cooking chemical. The obtained pulp can be used in fine paper and board production as short-fibered material, for instance. The invention also relates to a process for adjusting the hemicellulose content of the pulp in connection with the formic acid cooking by using acetic acid as an additional cooking chemical.

Abstract: A process for the delignification and bleaching of chemical paper pulps comprising one or more stage(s) of treatment with hydrogen peroxide, at a temperature greater than 100° C. and under high pressure, in the presence of a polymer and of a compound A chosen from potassium hydroxide, sodium hydroxide and alkali metal or alkaline-earth metal carbonates.

Abstract: The invention relates to a process for digesting woodchips used in papermaking. The process employs a digester additive, which is a mixture of (a) a polyglycoside, and (b) a polyoxyalkylene glycol. The digester additives are compatible and stable at elevated temperatures in the highly alkaline white liquor used in the digestion of woodchips into pulp. The invention also relates to the digester additive compositions.

Abstract: There is provided a new and useful process for peroxide bleaching of mechanical or high yield pulp, the process comprising adding to a pulp slurry at least one stabilizer for stabilizing low valency states of transition metal ions in the slurry; subsequently adding caustic soda to said slurry simultaneously with or subsequent to adding said at least one stabilizer; adding hydrogen peroxide to the slurry at a preselected point; and subjecting the slurry to preselected conditions to complete the bleaching process.

Abstract: Methods for bleaching chemical pulps are disclosed including a final bleaching sequence of bleaching with chlorine dioxide, treating with a chelating agent, in which the bleaching and treating steps are carried out in sequence without an intermediate washing step, washing the bleached pulp, and bleaching with hydrogen peroxide.

Abstract: A method for preparing pulp from lignin-containing cellulosic material is disclosed, including a step for acid cleaning of the lignocellulosic material, followed by alkaline delignification. The acidic step removes undesired components such as metal ions and side groups of polysaccharides, which may have adverse effects on the process especially when extensive recycling of liquors is employed within the plant.

Abstract: The present invention is a method for producing pulp from fibrous lignocellulose material using a treatment step which exposes the material to oxalic acid, or oxalic acid and sodium bisulfite, prior to pulping. The pulping of the resulting product requires less energy input and provides a pulp having enhanced physical properties as compared to untreated materials.

Abstract: The invention relates to a method of preparing chemical pulp and xylose by the use of alkaline or neutral cooking and post hydrolysis of the pulp by performing the post hydrolysis directly on the pulp by means of acid treatment. In the method of the invention, the xylan in the pulp is utilized as completely as possible, resulting in a good xylose yield and, simultaneously, acceptable characteristics for the pulp.

Abstract: A process for peroxide bleaching of pulp using magnesium oxide or magnesium hydroxide as a substitute for caustic soda wherein the pulp is bleached in the presence of hydrogen peroxide characterized in that the concentration of ion present in the magnesium oxide or magnesium hydroxide and the pulp is maintained less than 20 ppm and/or the concentration of manganese is maintained less than 10 ppm.

Abstract: In a process for extracting cellulose from fibrous materials such as wood, the fibrous materials are reacted with a chemical disintegration solution in the presence of organosilicic compounds.

Abstract: Composite panels and pulp, and paper products of the pulp, are produced from Arundo donax. In the fabrication of the composite panels, Arundo donax is comminuted to a suitable size, combined with a binder, and consolidated into panels that meet standards for construction and/or furniture grade panels. The Arundo donax particulates may be combined with wood particulates to produce a mixed furnish that can be used in the preparation of composite panels. Comminuted Arundo donax is treated, in conventional pulping processes, to produce a high tensile strength pulp that can be used in the production of paper. The pulp has a lighter color than wood pulp, and thereby uses less bleaching chemicals to achieve a desired whiteness. The pulp can be combined with wood pulp to produce a variety of products.

Abstract: The invention relates to a method of bleaching and/or delignifying cellulose, in which (a) a sodium hydroxide solution and a peroxydisulphate solution are first of all produced by electrolysis of a sulphate, (b) the peroxydisulphate solution is converted by hydrolysis into a Caro's acid/caroate solution, (c) said Caro's acid/caroate solution is left to cool and (d) used immediately as a bleaching solution for bleaching and/or delignifying cellulose, the Caro's acid/caroate solution becoming neutralised upon introduction into the bleaching solution.

Abstract: Pulps or papers, especially chemimechanical or thermomechanical pulps or papers, which still contain lignin, have enhanced resistance to yellowing when they contain an effective stabilizing amount of a hindered amine compound which preferably is a nitroxide, a hydroxylamine or an ammonium salt thereof. This performance is often further enhanced by the presence of one or more coadditives selected from the group consisting of the UV absorbers, the polymeric inhibitors, the nitrones, the fluorescent whitening agents, metal chelating agents, sulfur containing stabilizers, metal salts and diene compounds. Combinations of nitroxides, hydroxylamines or their salts, benzotriazole or benzophenone UV absorbers and a metal chelating agent are particularly effective. Selected derivatives of 1-oxyl-2,2,6,6-tetramethyl-piperidin-4-ol and selected hydroxylamine salts are novel compounds and are surprisingly effective for this purpose.

Abstract: A method to remove scale build-up in a vessel having at least one screen is described and involves placing a cover inside the vessel such that it is located beneath at least one screen to separate the screen from the rest of the vessel. The cover in the vessel forms an upper portion and a lower portion in the vessel. Preferably, the cover is in close proximity to the screen which is located in the upper portion of the vessel. The method then further includes introducing a chemical formulation into the upper portion of the vessel in a sufficient amount to remove at least a portion of the scale build-up on the screen. A system to remove scale build-up is also described and includes a vessel having at least one screen. The system further includes a cover located inside the vessel and beneath at least one screen to separate the screen from the rest of the vessel and to form an upper portion and a lower portion in the vessel. Normally the cover is in close proximity to the screen.

Abstract: The production of chemical (e.g., kraft) cellulose pulp much more suited to totally chlorine free or elemental chlorine free bleaching is produced by reducing the bleaching chemical consumability of the produced pulp. The effective alkalinity of the pulp during at least the majority of the cooking stage is maintained at about 15 g/l or above (e.g., about 18-25 g/l), expressed as sodium hydroxide, so as to reduce the charged acid groups (including hexeneuronic acids) by at least 30% (e.g., at least about 50%) compared with pulp cooked at conventional alkalinity. Instead—or in addition to—the cellulosic material which produces the pulp may be heated to a temperature (at least about 100° C., preferably at least about 130° C.

Abstract: The present invention relates to methods for deinking wastepaper by pulping wastepaper at a pH between 4 and 8.5 in the presence of deinking agents comprising a lipase and a fatty acid ester and removing the thereby dislodged ink particles.

Abstract: The present invention relates to a new method for producing microcrystalline cellulose using never-dried pulp as the cellulose source.

Abstract: The amount of metals that can be removed from comminuted cellulosic fibrous material (such as wood chips) in the production of chemical pulp, prior to bleaching, is enhanced by extracting metals during an early stage of digestion, and prior to the addition of a chelating agent. After the material is steamed and slurried it is impregnated with cooking liquor at a temperature of 90° C. or more, and during or after impregnation metals are removed by an extraction (e.g. in a continuous digester), which typically removes about 30% or more of the Mn. Prior to this extraction it is not necessary to introduce chelating agents, and undesirable to do so since they may compete or interfere with the natural removal of metals. After the extraction, such as during the first part of cooking, about 0.05-10 kg/dry ton of material of chelant (such as EDTA) is added, and the chelant combines with released metal ions in the slurry to produce metal complexes. The metal complexes are substantially removed before bleaching.

Abstract: Processes are disclosed for bleaching pulp with ozone in an environmentally friendly bleaching plant. The processes include removing a first filtrate from the pulp, bleaching the treated pulp with ozone, washing the bleached pulp with a washing liquid to provide a washed bleached pulp and a second filtrate including oxalic acid, recycling the second filtrate to the pulp prior to the bleaching step, and transferring the first filtrate to the bleached pulp.

Abstract: A process for preparing a bleached sulfite chemical pulp includes delignification of chips of a lignocellulosic material in a sulfite pulping process until the defibration point of the material is reached, and bleaching of the fibrous material thus obtained by a chlorine-free bleaching sequence which includes at least one first bleaching step with a chlorine-free oxidant in the presence of a base. The chemical pulp prepared according to this process and paper or nonwoven made from such pulp have a high degree of brightness (at least 83% ISO) and high strength.

Abstract: Pulps or papers, especially chemimechanical or thermomechanical pulps or papers, which still contain lignin, have enhanced resistance to yellowing when they contain an effective stabilizing amount of a hindered amine compound which preferably is a nitroxide, a hydroxylamine or an ammonium salt thereof. This performance is often further enhanced by the presence of one or more coadditives selected from the group consisting of the UV absorbers, the polymeric inhibitors, the nitrones, the fluorescent whitening agents, metal chelating agents, sulfur containing stabilizers, metal salts and diene compounds. Combinations of nitroxides, hydroxylamines or their salts, benzotriazole or benzophenone UV absorbers and a metal chelating agent are particularly effective. Selected derivatives of 1-oxyl-2,2,6,6-tetramethylpiperidin-4-ol and selected hydroxylamine salts are novel compounds and are surprisingly effective for this purpose.

Abstract: The invention relates to a process for digesting woodchips used in papermaking. The process employs digester additive, which comprises a sultaine or mixtures of a sultaine with a nonionic surfactant selected from the group consisting of (a) polyglycosides, (b) polyoxyalkylene glycols, and (c) mixtures thereof as digester additives. The digester additives are compatible and stable at elevated temperatures in the highly alkaline white liquor used in the digestion of woodchips into pulp. The invention also relates to the digester additive compositions.