Abstract: The arrangement is for washing and dewatering a fiber pulp suspension. The arrangement comprises two hollow, circular-cylindrical screen members that have evacuation chambers arranged inside the screen members for leading off liquid. The screen members rotate counter to each other to form a nip. At least one of the screen members is arranged in a trough that partially encloses the jacket of the screen member and, in the direction of rotation of the screen member, converges towards the jacket of the screen member. A sealing arrangement for a pulp head box distributes the pulp onto the jacket surface of the screen members. By forming a progressively decreasing gap B-A at the pulp head box counter to the rotation of the screen member, a simple self-sealing of the pulp suspension can be obtained which allows fiber residues to be returned to the dewatering zone.

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 replaceable wearing surface is for a sealing arrangement on drum end walls on a press drum that de-waters fiber suspensions radially into the drum through the shell of the drum. The wearing surface of the sealing arrangement has a wear ring and holder members. The wear ring is, on a side that faces into the drum from the drum end-wall, provided with locking members. The locking members are arranged parallel to the drum axis and are preferably in the form of knob-shaped locking members. The arms of the holder members are designed to engage the locking members. The holder members are fastened to the drum end wall by suitable fixing members.

Abstract: A method for supplying a gaseous medium to a fluidized bed boiler through several pipes of a pipe grate. An active area of the grate is adjusted with a pipe-specific control included in at least some of the pipes of the pipe grate. A supply of gaseous medium to the pipe grate takes place in the active area. The active area of the grate is reduced by forming at least one inactive bed area that is out of use.

Abstract: Device for the washing and dewatering a fibrous suspension, which device incorporates two hollow, circular cylindrical filter drums (1), which filter drums incorporate evacuation chambers inside the filter drums for evacuation of fluid. The filter drums rotate in opposite directions to create a pinch (2) where at least one of the said filter drums (1) is installed in a trough (7,8) which partly encloses the outer surface (3) of the filter drum and which, in the direction of rotation of the filter drum, converges towards the outer surface of the filter drum. At least one pulp inflow chamber (4) is installed at the highest point (1) of one or both of the filter drums each equipped with a trough for the introduction of pulp between the outer surfaces (3) of the filter drum and its trough (7,8) for the formation of a fibrous web.

Abstract: A method of reducing NOX compounds in the odor gases of a recovery boiler. In the method, ammonia in the odor gases is separated before the odor gases are combusted, the ammonia being then introduced into a recovery boiler at the pulp mill or in a separate catalyzer, where the ammonia reacts with nitrogen oxide forming water and molecular nitrogen.

Abstract: A method for continuous cooking of lignocellulosic fiber material, comprising the steps of sequentially (a) in a first stage, impregnating the fiber material in an impregnation liquid comprising alkali metal hydroxide, and thereafter withdrawing (14, 514) a spent impregnation liquid; (b) in a second stage, cooking the fiber material in a cooking liquor comprising alkali metal hydroxide; and (c) in a third stage, adding (A), to said fiber material, a liquid which is rich in hemicellulose, said liquid preferably comprising at least a part (14a, 514a) of said withdrawn spent impregnation liquid. In a fourth stage (d), the fiber material is cooked in a cooking liquor comprising the liquid added in the third stage, whereby the fiber material is subjected to a retention time of at least 1 hour in said fourth stage.

Abstract: A fluidized bed material including mineral particles of a gabbro class or darker rock type. The rock type includes several minerals and having a quartz content of 5 wt-% or less. The particles are made by comminuting a gabbro class or darker rock type. A fluidized bed process including performing a reaction or a processing of a material in a fludized bed reaction in connection with the fluidization of a fluidized bed material, wherein the fludization bed material includes particles of the gabbro class or darker rock type.

Abstract: The distributor device is for cellulose pulp of low and medium consistency and is used to form a uniform pulp web running from the distributor device in an apparatus treating the cellulose pulp. The distributor device has a cylindrical distributor housing arranged horizontally and transverse to the pulp web, and an inlet for the cellulose pulp at one end of the distributor housing and on the pulp web side. Pulp is fed with feed screws from the inlet and along the length of the distributor housing. The web is initially formed via the outlets defined along a generatrix in the jacket surface of the distributor housing. An optimum distribution of low-concentration pulp is obtained with the holes arranged along the generatrix in the jacket surface of the distributor housing. The holes have a defined hole diameter (D) and are arranged at a distance (X) from each other. The interaction with the feed screw makes it possible to keep the holes free from clogging.

Abstract: A pipe attachment comprises a pipe elbow that is tightly attached to a stand pipe so that the diameter of the stand pipe is greater than the diameter of the pipe elbow.

Abstract: The invention relates to a process for continuous cooking of wood chips at elevated pressure and temperature in a vertical digester (1) for production of chemically dissolved pulp.

Abstract: The invention relates to a process for continuous cooking of wood chips at elevated pressure and temperature in a vertical digester (1) for production of chemically dissolved pulp.

Abstract: The strainer arrangement is adapted for straining a liquid from a mixing arrangement, such as a mixing tank, containing black liquor including solid particles of ash. The strainer arrangement comprises a strainer pipe with axial gaps defined therein for permitting a radial inflow of liquid into the strainer pipe. An axially movable shaft is disposed inside the strainer pipe and has cleaning pins attached thereto that extend into the gaps.

Abstract: A system and a process for the oxygen delignification of pulp consisting of lignocellulose-containing material whose mean concentration is 8-18% pulp consistency, in at least two stages. The invention is characterized in that the oxygen delignification takes place in a first stage with a short dwell time of approx. 3-6 minutes, at a low temperature of approx. 85° C. and under a low pressure of approx. 0-4 bar, followed by a concluding stage with a longer dwell time of approx. 50-90 minutes, at a higher temperature of approx. 100° C. and under a higher pressure of approx. 8-10 bar. This makes it possible, in an industrial process, to exploit the kinetics of the oxygen delignification in an optimal manner for the purpose of obtaining a selective oxygen delignification at low installation cost and at low operating cost.

Abstract: A screw press inlet section comprises a housing defining a radial inlet opening leading to an axially extending chamber through which a screw is rotatably mounted for conveying and dewatering a solid-liquid mixture fed into the chamber through the inlet opening. The housing has an end wall extending in a plane normal to the screw and to which a perforated plate is integrated to provide the additional surface available for drainage at the inlet section. A pulsator is provided within the housing to generate hydraulic pulses against the perforated plate so as to prevent plugging thereof.

Abstract: Device for the washing and dewatering a fibrous suspension, which device incorporates two hollow, circular cylindrical filter drums (1), which filter drums incorporate evacuation chambers inside the filter drums for evacuation of fluid. The filter drums rotate in opposite directions to create a pinch (2) where at least one of the said filter drums (1) is installed in a trough (7,8) which partly encloses the outer surface (3) of the filter drum and which, in the direction of rotation of the filter drum, converges towards the outer surface of the filter drum. At least one pulp inflow chamber (4) is installed at the highest point (1) of one or both of the filter drums each equipped with a trough for the introduction of pulp between the outer surfaces (3) of the filter drum and its trough (7,8) for the formation of a fibrous web.

Abstract: The invention relates to a quick cone (1) for pipe assemblies for conducting fiber suspensions wherein the quick cone provides a transition from a pipe (8) with a greater diameter to a pipe (9) with a smaller diameter as seen in the flow direction of the fiber suspension. The invention is characterized therein that the quick cone (1) has a pipe (2) wherein the pipe (2) has a major portion of its axial extension concentrically enclosed by a jacket (3) that includes a conical jacket portion (4) that is shaped as a cut cone and a cylindrical connection segment (5) where a thicker end of the conical jacket portion (4) is in engagement with the cylindrical connection segment (5) that has substantially the same diameter as the larger diameter pipe (8) and the pipe (2) has substantially the same diameter as the smaller diameter pipe (9) and wherein the more pointed end of the jacket portion (4) is tightly attached to the pipe (2).

Abstract: A method in connection with continuous cooking of chips, comprising impregnation of the chips with impregnation liquid in an impregnation vessel (3) and cooking of the impregnated chips in a digester (4), the impregnation vessel and the digester being connected to each other by means of a transfer circulation, which partly, via a feed line (25), feeds the chips from an outlet end (27) of the impregnation vessel to the top of the digester for separation of free liquid in a separator (28), and partly, via a return line (26), feeds separated liquid from the top of the digester to the outlet end of the impregnation vessel for use as transfer liquid for the impregnated chips, besides which cooking liquid is added to the chips in the top of the digester. According to the invention, as a first part, less than 100%, preferably less than 95% and more preferred less than 90% of the liquid which is separated from the chips in the transfer circulation, is recirculated to be used as transfer liquid.

Abstract: The apparatus is used for adding a first fluid to a second fluid. The apparatus has a tube-shaped element. The tube-shaped element has a flow-through channel defined therein for carrying the flow of the second fluid. The flow-through channel has, a substantially constant first cross-sectional area and maintains a first pressure. The apparatus has a chamber defined therein that extends about the tube-shaped element and along a length of the tube-shaped element. The chamber maintaining a second pressure that is greater than the first pressure. A connection supplies the first fluid to the chamber. The tube-shaped element has a plurality of openings defined therein. The openings are disposed adjacent to the chamber so that the first fluid flows through the openings into the second fluid flowing inside the tube-shaped element. A second conduit is attached to the tube-shaped element and directly downstream thereof.

Abstract: A method and apparatus for introduction of a first fluid into a second fluid, that flows in a conduit. A first member with a pass-through canal for said second fluid, is at least partially encircled by a chamber with a wall between the inner part of the chamber and the pass-through canal, and a pressurized source of first fluid which is to be supplied into the chamber. At least one series of apertures is distributed about the periphery of the wall, extending there through, such that the first fluid is introduced through the apertures to be mixed into the second fluid based upon the pressure differential between the pressure in the chamber and the pressure in the pass-through canal. At least a portion of the apertures may be selectively blocked or closed to regulate the flow of the first fluid into the pass-through canal.