Abstract: The invention relates to a method for separating hemicelluloses from a biomass containing hemicelluloses. The method includes the steps of: a) extracting the hemicelluloses from the biomass containing hemicelluloses by treating them with a complex compound in an aqueous solution, and forming a soluble hemicellulose complex, and b) separating the complexed hemicelluloses from the biomass. The method is especially suitable for producing high-quality chemical conversion pulp from raw cellulose. The products produced with the method of the invention have a high degree of purity, and the method is extremely economical and causes few emissions. Hemicelluloses in a pure form can be obtained as by-products of the method.

Abstract: In a process and an arrangement for directing a papermaking pulp towards a regulated outlet (9), accept from successive cleaning stages (6, 14, 20) is totally or partly led towards the outlet (9) while excess accept is led in the opposite direction to the inlet (5) of the preceding cleaning stage (6). For feeding of a forming wire, a common base pipe (8) for collecting accept extends between the outlet (9) and a feeding (3) for fresh pulp, while reject pipes (11, 18) lead to the next cleaning stage (14, 20).

Abstract: The invention relates to a method for continually producing a suspension of cellulose in an aqueous tertiary amine oxide. The method includes (a) mixing cellulose and an amine oxide-free aqueous phase to form a cellulose suspension in a mass ratio in the range of 1:3 to 1:40, (b) dehydrating the cellulose suspension, wherein the dehydrated cellulose suspension has a cellulose content in the range of 20 to 80 percent-by-mass; (c) mixing the cellulose suspension with an aqueous amine oxide while the cellulose suspension is falling through a vertical fall zone to obtain an aqueous amine oxide-cellulose suspension with an amine oxide content in the range of 70 to 80 percent-by-mass; and (d) conveying the aqueous amine oxide-cellulose suspension through a horizontal shear zone. The invention also relates to a device for carrying out this method.

Abstract: The invention relates to a process for producing pulp from a fibre-based raw material using, as the cooking reagent, a solvent mixture which is based on organic acids and also contains furfural. The method is applicable to herbaceous plants, in particular.

Abstract: The method is for bleaching cellulose pulp in a bleach line that has at least two bleaching steps. The filtrate distribution is led up through the bleaching line counter-currently to the flow of cellulose pulp established in the bleaching line. A single joint main conduit is used for the bleaching steps. Wash filtrates obtained from the wash steps, used after or before the bleaching step, are led in conduits to branch locations on the train conduit that are positioned downstream of the branch location for drawing off of wash and/or dilution liquor for the wash step in question. All branch points in the joint main conduit are in fluid communication with one another along the main conduit.

Abstract: A method of processing papermaking fiber includes characterizing the initial color of the pulp and the color of the pulp after treatment with a phloroglucinol stain. The color response of the pulp to the stain has been found to be a better indicator of processing needs for secondary pulps in particular and in any event is selective for untreated groundwood as opposed to conventional groundwood identification methods. The color difference is used to target a suitable product for the pulp, to aid in bleaching/deinking strategy or to enable optimization of fiber blending for particular products. In a preferred embodiment the process includes determining changes in CIE L*, a*, b* and brightness values before and after staining of the pulp.

Abstract: A method for brightening pulp at a pH from 4.5 to 9. The method comprises the steps of: (a) combining an alkali metal borohydride, an alkali metal hydroxide, an alkali metal bisulfite and phosphoric acid to form a reducing solution; and (b) adding the reducing solution to a pulp slurry in an amount from 0.1% to 4% of hydrosulfite based on dry pulp fiber.

Abstract: The invention relates to a method for supplying washing liquid to a digester (1) for cellulose pulp and a subsequent diffuser washing device (2a, 2b). A high, disturbance-free production capacity can be obtained by using a common feed pump (P1) which, via a main feed line (10), supplies both the diffuser washing device and the digester with washing liquid in parallel. The first pump (P1) establishes a pressure on the washing liquid which is in the interval 2–6 bar, and is preferably 4 bar, while the second pressure level, which is established by the diffuser pump device (P2a, P2b), is in the interval 6–12 bar, but is at least 2 bar higher than the first pressure level, and the third pressure level, which is established by the digester pump (P3), is in the interval 12–25 bar The system becomes self-regulating in the event of any operational disturbances in the flow of washing liquid and, if the pumps are appropriate, a countercurrent flow of washing liquid through the system is essentially maintained.

Abstract: The present invention relates to a new and environmentally sound process for the manufacturing of a chemical pulp from lignocellulosic material with an integrated recovery system for recovery of pulping chemicals. The process is carried out in several stages involving a pre-treatment stage followed by one or more delignification stages using an alkaline buffer solution comprising alkali metaborate and sodium carbonate as major components. The alkaline components of the pulping liquor are recovered from a chemicals recovery furnace and at least a portion of the alkali is recycled and used for delignification without any prior reactions with lime or calcium compounds for generation of alkali hydroxide. A quinone based delignification catalyst may be added to be present during delignification.

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.