Abstract: The invention relates to a heat transfer tube (9) for falling film evaporation having a heating medium surface (21) to be heated by a heating medium, a falling film surface (20) to have spent liquor passing over it, and being made from an iron based high alloy stainless steel material with an alloy content above 16.00% for Chromium and above 1% for Nickel. The falling film surface of the heat transfer tube is equipped with at least one weld ridge (WR; WR1, WR2), said weld ridge having a height (h; h2) in the range 0.3 to 5.0 mm, a width (w; w2) in the range 0.

Abstract: A center plate for a rotor in a pulp refiner has a surface provided with at least one feeding wing for directing lignocellulose-containing material towards a periphery of the center plate. The at least one feeding wing is an elongated protrusion arranged such that its second end is arranged further away from a center of the center plate than a first end and is also displaced relative to the first end in a direction opposite to a direction of rotation of the rotor. The at least one feeding wing includes at least one opening allowing steam to flow through the opening in a direction having a component directed opposite to the direction of rotation.

Abstract: The invention relates to a pulp refining system for mechanically refining of lignocellulosic material, comprising a defibrator, a defibrator housing, in which the defibratoris arranged, a blow valve having an inlet and an outlet and being adapted for regulating a flow of pulp therethrough, and a discharge pipe having an inlet, which is connected to the outlet (12) of the blow valve, wherein a mounting pipe having an inlet, which is connected to the defibrator housing, is arranged between the defibrator housing and the blow valve, said mounting pipe having a length of at least about 0.2 meter.

Abstract: A refiner is disclosed comprising relatively rotatable inner and outer conical refining blades. The refining blades are coaxially arranged around a symmetry axis and are provided with first bars and second bars, respectively, for the grinding of fibrous material. The inner conical refining blade or any of the first bars of the inner conical refining blade extend further along the symmetry axis, in the direction of the tapering of the inner and outer conical refining blades, than the outer conical refining blade or any of the second bars of the counter conical refining blade.

Abstract: A method for processing pulp in an apparatus for washing and dewatering pulp, and a system for controlling this apparatus, the apparatus comprising two rotatable press rolls (102, 104) having a permeable outer surface (106, 108), and a vat (114, 116, 118), the press rolls (102, 104) defining a press nip (112) between them. The processing is determined by a set of variable operating parameters, which are adjusted and/or maintained during operation in response to deviations of measured values of control parameters in relation to their respective predetermined threshold values. The variable operating parameters include rotation speed of the press rolls. The control parameters include vat pressure and/or linear load.

Abstract: A feeding arrangement for feeding lignocellulosic biomass material such as annual plant material towards a hydrolysis process includes at least one transportation device for transporting the biomass material towards the treatment process; and at least one tearing roll arranged at a predetermined distance from the at least one transportation device and being provided with tearing protrusion. The at least one tearing roll is arranged with a predetermined distance to the at least one transportation device to tear off parts of the transported material to provide a substantially continuous flow of material.

Abstract: A feeding arrangement for feeding lignocellulosic biomass material such as annual plant material towards a hydrolysis process includes at least one transportation device for transporting the biomass material towards the treatment process; and at least one tearing roll arranged at a predetermined distance from the at least one transportation device and being provided with tearing protrusion. The at least one tearing roll is arranged with a predetermined distance to the at least one transportation device to tear off parts of the transported material to provide a substantially continuous flow of material.

Abstract: The invention relates to a refiner plate segment in a refiner plate for mechanically refining of lignocellulosic material in a refiner, said refiner plate segment comprising at least a first, generally radially extending bar, a second, generally radially extending bar, a groove arranged and defined between said first, generally radially extending bar and said second, generally radially extending bar, and a main dam, which has a height H and is arranged in the groove, wherein a pre-dam is arranged in front of the main dam, said pre-dam has a height h which is less than the height H of the main dam.

Abstract: The invention relates to an improved method for generating clean steam in a digester plant of a chemical pulp mill. By feeding a steam-to-steam converter (SSC) with venting steam from a black liquor flash tank (FT) as well as venting steam from chip steaming (SV) could the volume of clean steam produced be increased by over 40-50%, and to such an extent that the volume of clean steam covers the needs for preheating of chips in the digester system also in severe operational conditions. The total consumption of clean steam from the steam net of the mill may be reduced and used for other purposes such as electricity production, which meets the requirements for converting the pulp mill to an environmental friendly pulp mill.

Abstract: The invention relates to a method and an impregnation vessel where the bulk volume of impregnation liquor added is in form of hot black liquor having a residual alkali content. Hot black liquor is added in an upper central pipe supplying the hot black liquor as impregnation liquor and flashing off steam for driving off air from the comminute cellulose material. During this first steaming is the wood acidity released from the material and spent impregnation liquor with wood acidity content is withdrawn from an upper withdrawal screen to recovery, a lower withdrawal screen recirculates the remaining impregnation liquor to a second lower central pipe in order to equalize the alkali content well before the remaining retention time in the impregnation vessel.

Abstract: A refiner segment (4) for a refiner (1) comprises refining zones (Z(x)) and is provided with a pattern of bars (10) arranged at a respective pumping feeding angle (?(x)) within a respective refining zone (Z(x)), and intermediate grooves (11) between the bars (10), and dams (12) extending between the bars (10) and protruding above the surface of the grooves (11).

Abstract: A screen feed arrangement for a pulp production process, comprising a discharge tank having an outlet, which is connected to an inlet of a discharge tank pump having an outlet, a dilution tank having an outlet, a screen feed pump having an inlet and an outlet, and a screening arrangement, wherein the outlet of the discharge tank and the outlet of the dilution tank are connected to the inlet of the screen feed pump, the outlet of which is connected to the screening arrangement, and that pulp which passes the outlet of the discharge tank has a mass concentration from about 8% to about 15%. A corresponding method for feeding pulp to a screen feed arrangement is also presented.

Abstract: A dewatering roll (10) comprises a roll body (20), a mantle support structure (30) and a mantle (40). The mantle support structure (30) is attached around the roll body (20). The mantle (40) is attached against an outer surface (36) of the mantle support structure (30). The mantle (40) has a plurality of through holes (42) constituting mantle flow paths (44). The mantle support structure (30) presents support flow paths (38) from the outer surface (36) of the mantle support structure (30). The support flow paths (38) are in fluid contact with the mantle flow paths (44). The outer surface (36) of the mantle support structure (30) has a static geometric shape defining an envelope having a smaller radius in vicinity of each axial end (15) than in vicinity of a center (16). Thereby, the inner surface (48) of the mantle (44) assumes the shape of the envelope.

Abstract: A refiner segment (4) for a refiner (1) intended for refining fibrous material (7) has a refining surface and is arrangeable to form a part of a refining surface of a refiner element (2; 3) in the refiner (1). The refiner segment (4) is provided with a pattern of bars (10) and intermediate grooves (11) extending along the refiner segment (4) in a substantially radial direction, and dams (12) extending between the bars (10) and protruding above the surface of the grooves (11).

Abstract: A discharge valve is disclosed which includes a valve housing which can be functionally connected to a process element having a pressurized interior space. The valve housing includes a flow channel having a longitudinal center axis (A) and is in working cooperation with a valve member. The flow channel is arranged to be in fluid communication with the pressurized interior space in the process element after the discharge valve has been connected to the process element. The valve member is displaceable between an open position and a closed position in a displacement direction (B) whereby the discharge valve can be opened and closed. The flow channel comprises a detachable inner lining having an envelope wall, and the detachable inner lining comprises an aperture extending through the envelope wall and through which the valve member is adapted to run when being displaced between the opened and closed positions.

Abstract: The invention is related to a method for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to obtain a cost efficient system both in aspects of investment costs but also in aspects of heat economy of operating the process is most of the total charge of alkali charged as heated polysulfide liquor to an first atmospheric vessel, wherein the hot polysulfide liquor flashes off steam providing most if not all of the necessary steaming effect for the cellulose material. The polysulfide liquor is then allowed to impregnate the cellulose material at a temperature closer to cooking temperature but still so low that essentially no delignification occurs in impregnation vessel, as the H-factor in impregnation vessel is kept within 1-20.

Abstract: A plug screw feeder (1) comprises a plug screw (10) with a thread (12) and a plug screw housing (20) surrounding the plug screw. The plug screw housing comprises an inlet opening (24) in a side of the plug screw and in a vicinity of a first axial end (18) of the plug screw. The plug screw is arranged for feeding lignocellulosic biomass material (99) from the inlet opening to a second axial end (19) of the plug screw when being rotated. The thread, in at least a part of an inlet section (15) of the plug screw, presents a jagged peripheral rim (14A) with an inwards directed leading edge. The inlet section is defined as the section of the plug screw passing the inlet opening during rotation. A feeding arrangement and system for treatment of lignocellulosic biomass material comprising such a plug screw feeder is also disclosed.

Abstract: The invention relates to an improved profile bar screen for draining treatment liquor from a suspension of comminuted cellulose material and treatment liquor in an essentially cylindrical digester vessel. According to the invention is a profile bar screen designed with horizontal support arches 11 with integrated support shoulders 12 only at the outer ends of the support arch which support shoulders rest against the inside of the vessel wall 1. The invention combines the techniques from self-supporting screens with support members of weaker screen designs, avoiding need to make any additional welds in the classified pressure vessel wall of the digester. Installation of new screens in compartments previously equipped with blind plates in checkered screen rows may be done quickly and at less costs during shorter down time of digester.

Abstract: The method is for separation of lignin from original black liquor (BLIN) that has a first precipitation stage (PR) for precipitation of lignin by a first acidification using acidifier AC1, preferably using CO2, at alkaline conditions, then separating a lignin cake with subsequent suspension of the lignin cake in a strong acid in order to leach our metals from the lignin followed by dewatering and obtaining a clean lignin product LP. The process further is improved by intensified hydrolysis of lignin cake such that most of the carbohydrates are broken down to dissolvable monomers that could be separated from the lignin in the filtrate from a filtering stage subsequent to the hydrolysis. The improved hydrolysis could reduce as much as 90% of the carbohydrate content using a moderately increased temperature and increased charge of acidifier while avoiding any larger lignin yield losses.

Abstract: A center plate for a rotor in a pulp refiner has a surface provided with at least one feeding wing for directing lignocellulose-containing material towards a periphery. The feeding wing is an elongated protrusion arranged such that its second end is arranged further away from a center of the center plate than a first end and also is displaced relative to the first end in a direction opposite to a direction of rotation of the rotor. The center plate is also provided with at least one counter-feeding wing for directing steam flowing along the surface towards the center of the center plate. The counter-feeding wing is an elongated protrusion arranged such that a second end of the counter-feeding wing is arranged further away from the center of the center plate than a first end and closer to the center of the center plate than the first end.