Abstract: The present invention concerns a method for enzymatic treatment of lignocellulosic materials which contain xylan-polymers, such as cellulose kraft pulps. According to a method of the present kind, at least a part of the hexenuronic acid groups present in the material is selectively removed in order to remove metal ions from the pulp, to change the surface charge thereof, to improve the brightness stability of the pulp and to render the material more suitable for enzymatic treatment.

Abstract: Lignocellulose pulp is bleached by bleaching a pulp in aqueous alkali solution with oxygen and treating the pulp with a hemicellulase, while a liquid fraction delivered from the enzyme treatment step is separated from the hemicellulase treated reaction mixture, and subjected to a penetration treatment through a separation membrane, for example, reverse osmosis membrane, to separate a permeated fraction from a non-permeated fraction; the permeated fraction is fed to the alkali-oxygen bleaching (oxygen delignification) step and is used as a liquid medium of the bleaching system.

Abstract: The invention relates to a process for the treatment of fly ash accumulating in the electro-filter of the soda recovery unit in a sulfate cellulose mill, the ash containing primarily Na sulfate, Na chloride, Na carbonate and K sulfate, to produce industrial raw materials, in which process the fly ash is dissolved in water, the carbonate present therein is broken down with hydrochloric acid to Na chloride, a sulfate precipitation chemical in chloride form is added, the sulfate precipitate obtained is separated from the solution, and the chloride-containing solution is recovered.

Abstract: The invention concerns a method and an equipment for combining in one single apparatus, the functions for filtering, decontaminating, and thickening paper pulp from used paper, while providing the complementary function of clarifying the filtrates. The apparatus (1) rotates at high speed. The paper pulp is introduced through the center of the apparatus (2) and driven at its angular speed. The pulp is then brought along a grate (6) with small size holes for separating the fibers from the greater part of the water. The thickened pulp is evacuated through extraction nozzles (8). The water is clarified in the clarification zone (12) and recycled or eliminated depending on uses. More complete embodiments of the apparatus include the functions of fractionating, de-inking and purifying the pulp with slots or holes.

Abstract: A method and an apparatus for mixing dilution liquid into a stock flow in a paper or board machine. Dilution is carried out in at least two stages using in the first dilution stage (I) valves (V1, V2, V3 . . . ) fitted with a larger mutual spacing at different points of width across a headbox and passing the dilution water through the valves to desired points of width of the headbox according to the requirement of control of the basis weight of paper or board. In the second dilution stage (II), dilution water is passed into connection with the stock flow coming from the first dilution stage (I), said dilution water being controlled by means of valves (V1′, V2′ . . . ), which valves (V1′, V2′ . . . ) have been fitted with a denser spacing than the valves (V1, V2, V3 . . . ) of the first dilution stage (I).

Abstract: Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1-5 weight %. Such a low consistency slurry is then mixed with ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.

Abstract: A method to remove sulfides and other volatile contaminants from liquor vapor condensate in a pulp manufacturing process, where the mentioned liquor vapor condensate is fed into a stripper, which is part of a closed loop system including the stripper, a regenerative thermal oxidization process (RTO) and a SO2 scrubber, in which loop a gas is circulated, preferably air, and such components formed or stripped off, in this loop whereafter the circulating gas is stripped off sulfides and other volatile components from the liquor vapor condensate, whereafter the gas stream is fed into a RTO process, where the stripped off contaminants are combusted are under formation of SO2 and thereafter the SO2 enriched gas is led to a SO2 scrubber, where preferably alkali is used as absorption medium, and thereafter the circulating gas is returned back into the stripper.

Abstract: Chemical cellulose pulp produced by alkaline delignification and having a kappa number of under 24 (e.g. 14 or below) having hexenuronic acid is treated to remove at least 50% of the hexenuronic acid (e.g. 90-97%) such as by treating the pulp at a temperature over 85° C. (e.g. about 90-180° C., preferably about 90-110° C.) at a pH between about 2-5 (e.g. about 2.5-4), which also results in a reduction of kappa number by at least two units (e.g. about 2-9 units, preferably about 3-6 units). The treatment time t, in minutes, is at least 0.5 exp(10517/(T+273)−24), where T is the treatment temperature in degrees C. The chemical cellulose pulp is bleached in at least one bleaching stage; where the bleaching stage is a chlorine dioxide, ozone, or peracid, treatment takes place before bleaching. Under some other circumstances treatment can take place simultaneous with bleaching or after bleaching.

Abstract: Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1 up to 5 weight %. Such a low consistency slurry is then mixed with high partial pressure ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.

Abstract: The invention provides a method for predictively assessing one or more characteristics of wood pulp produced from solid wood. The method comprises the steps of determining the velocity of sound through the solid wood, and assessing characteristic(s) of wood fiber or wood pulp produced from the wood by reference to the velocity of sound through the solid wood. The method may also comprise the steps of causing a sound wave to be transmitted through the wood, determining the velocity of the sound wave through the wood, and comparing the result to stored information on fiber characteristic(s) versus sound velocity through the wood-type to determine the fiber characteristic(s) for the wood.

Abstract: The present invention is directed to a method and apparatus for fiberizing bales of pulp into substantially dry fibers and fiber aggregates, i.e., dry fluff, and metering the resulting dry fluff to a receptacle or other process, such as an airlaid process for making disposable absorbent articles.

Abstract: A substantially sulfur free process for the manufacturing of a chemical pulp with an integrated recovery system for recovery of pulping chemicals is carried out on in several stages involving physical and chemical treatment of lignocellulosic material in order to increase accessibility of the lignocellulosic material to reactions with an oxygen-based delignification agent. Spent cellulose liquor comprising lignin components and spent chemical reagents is fully or partially oxidized in a gas generator wherein a stream of hot raw gas and a stream of alkaline chemicals and chemical reagents is formed for subsequent recycle and reuse in the pulp manufacturing process.

Abstract: The present invention relates to the thickening of pulp suspensions. A low consistency pulp suspension is fed to a pre-thickener (10) through an inlet conduit (18). A layer of thickened pulp, formed on a filter surface (22), is pushed along the filter surface by a cleaning member to the discharge end of the pre-thickener and is discharged through the outlet (20). The cleaning member comprises a rotating shaft (30) on which shaft at least one screw thread (32) is fixed so as to leave a free space between the shaft and the screw thread. Essentially non-thickened pulp is allowed to flow through the apparatus via this space.

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: For a process and an apparatus for loading fibers contained in a pulp suspension with calcium carbonate, a calcium oxide and/or a medium containing calcium hydroxide is fed to the pulp suspension, and the so treated pulp suspension is further charged in several reactors with pure carbon dioxide or a medium containing carbon dioxide. The reactors can be connected in series and/or in parallel.

Abstract: A method in bleaching of pulp is described, in which the pulp is subjected to a peroxide bleaching step, whereupon the pulp is washed and the washing liquid from the washing is separated from the pulp in the form of a filtrate. The method is characterised in that the filtrate is treated with an aluminium compound, such as aluminium sulphate or polyaluminium sulphate, for precipitation of interfering substances, such as oxygen-demanding organic material and metals, that the precipitated material is removed from the filtrate, that the aluminium content of the filtrate after precipitation of interfering substances is adjusted to at most 20 ppm, and that the filtrate is then recirculated to the peroxide bleaching step. By the method, a reduced consumption of hydrogen peroxide in the peroxide bleaching step is achieved.

Abstract: The product is presented in the form of a solution and is composed of carbonated magnesium di-n-propylate, n-propanol, and a hydrofluorocarbon (HFC) diluent selected from 1,1,1,2-tetrafluoroethane (HFC 134a) and 1,1,1,2,3,3,3-heptafluoropropane (HFC 227). The product may be obtained by a procedure which comprises preparing a solution of carbonated magnesium di-n-propylate in n-propanol and diluting said solution by addition of the HFC diluent. The product is suitable for de-acidifying cellulose-type material and preserving objects based on cellulose-type material.

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.

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 paper and absorbent products of increased strength includes extracting wood particulates with a solvent selected from methanol, ethanol, and acetone at a pressure less than 50 psi to reduce the pitch and volatile organic compounds of the particulates without significant dissolution of lignin and cellulosic components. The wood particulates are pulped to produce a pulp with reduced pitch content. A slurry is prepared from the pulp and used to form paper products.