Abstract: A method for treating liquid flows at a chemical pulp mill including at least an alkaline cooking process for producing pulp, treatment of brown stock generated in the cooking, a bleaching plant using ECF-bleaching, in which chloride-containing effluents are formed, an effluent purification plant for treating bleaching plant effluents and other effluents generated at the mill. At least a portion of the effluents is returned after the purification to the pulp production line as source of process water. More than one treatment line is arranged at the effluent purification plant for the mill effluents and effluents with different chemical compositions are purified in separate treatment lines so that the quality and amount of purified water from each treatment line is suitable for use in a stage or stages of the production process, whereto purified effluent is returned.

Abstract: An apparatus in connection with wire water treatment in the approach system of a paper machine, board machine or corresponding web formation machine, which apparatus includes a deaeration tank connected to devices for generating a vacuum inside the deaeration tank. At least one wire water feed pipe extends into the tank, which pipe opens into a vacuum space above the liquid surface level in the tank. A wire water discharge duct is connected to the bottom part of the tank. The feed pipe extends above the liquid level in the tank so that the wire water overflows the edge of the feed pipe onto the liquid level in the tank and the wire water discharge conduit extends downward and is connected to a pump.

Abstract: An arrangement is disclosed for supplying an air jet form to the furnace of a recovery boiler, where the furnace has a front wall, a rear wall and side walls. Black liquor spraying devices are disposed on the furnace walls on one or several levels of the furnace. A plurality of air ports are located at several horizontal elevations for introducing air into the furnace from an air supply. In the arrangement for the secondary air flows, at least two horizontal air levels at different elevations are arranged above the lower primary levels and below the black liquor sprayer. Secondary air is supplied from two opposite walls. The secondary air ports on each of said first and second horizontal elevations comprise air ports for each horizontal elevation that project a pattern of large air jets into the furnace from said opposite walls and said secondary air ports further comprise a plurality of secondary air ports on at least one of the elevations that project smaller air jets into the furnace.

Abstract: A method for feeding lime mud into a lime kiln including a rotary kiln shell having an interior between a first end wall and a second end wall, the method including: feeding the lime mud into a flue gas flow in the interior of the rotary kiln shell or in close proximity to the shell to pretreat the lime mud; separating the pretreated lime mud from the flue gas flow; conveying the separated lime mud into the lime kiln, and calcining the separated lime mud in the lime kiln.

Abstract: A spent liquor recovery boiler system including a boiler having a water/steam circulation system with superheaters and a furnace for recovering energy and chemicals from spent liquor combusted therein, the walls of the boiler are formed of a plurality of water-cooled tubes connected to the water/steam circulation system. The system is provided with at least one cavity having walls formed of water-cooled tubes connected to the water/steam circulation system, means for combusting a fuel and at least one outlet for discharging combustion gases to the boiler, the interior of the at least one cavity being provided with heat exchanger means for final superheating of the steam generated in the boiler, said heat exchanger means being connected to the superheaters of the boiler.

Abstract: The present invention relates to a method of processing logs by means of an apparatus comprising a transportation level in the advancing direction (P) of the logs, where they are arranged to be transported in a position perpendicular to their advancing direction (P), and where orifice members going therethrough and extending in the advancing direction (P) of the logs. In the method, at least two support member units spaced from each other are arranged below the transportation level whereby each support member unit comprises at least one elongated support member, which is arranged rotatably parallel to the transportation level and perpendicular to the advancing direction (P) and protruding therefrom, and said axis of rotation of each support member unit is adapted so that when rotating, the support members protrude through the orifice members above the transportation level whereby the logs are received in one or more receiving spaces formed between the support members protruding above the transportation level.

Abstract: A spent liquor recovery boiler in the pulp and paper industry including a water/steam circulation system having superheaters, the circulation system connected to a steam turbine comprising a high-pressure part, and a furnace for burning spent liquor to produce flue gases, and including an upper portion through which the flue gases flow, wherein the steam/water circulation system of the recovery boiler is provided with a reheater for reheating steam from the high-pressure part of the turbine.

Abstract: A method for feeding lime mud into a lime kiln including a rotary kiln shell having an interior between a first end wall and a second end wall, the method including: feeding the lime mud into a flue gas flow in the interior of the rotary kiln shell or in close proximity to the shell to pretreat the lime mud; separating the pretreated lime mud from the flue gas flow; conveying the separated lime mud into the lime kiln, and calcining the separated lime mud in the lime kiln.

Abstract: A cooling system for air ports and other ports in furnace walls includes a cooling medium pumping system and ports provided with a cooling medium piping or channels inside the metallic port material. The liquid flow generated by the cooling medium system cools the ports. The ports are constructed of a casting material, and the ports are provided with a cooling liquid flow, which passes in a piping or pipings or channels inside the casting material of the ports.

Abstract: The present invention relates to a method for reducing nitrogen oxide emissions in combustion. Fuel is combusted in a first zone, whereby nitrogen oxides are generated. Supplementary fuel is fed in another zone under reducing conditions. At the same time, the temperature is adjusted so that nitrogen oxides convert essentially to hydrogen cyanide. Finally, air is fed in for finalizing the combustion and converting the hydrogen cyanide into nitrogen.

Abstract: A method of dividing a suspension, especially a fiber suspension into an accept fraction and a fraction containing impurity particles in a centrifugal cleaning plant having at least two stages. The suspension is fed to a preceding stage, wherefrom a heavier fraction of the suspension is taken as accept fraction and a lighter fraction is taken as fraction containing impurity particles. The lighter fraction containing impurity particles is fed into a latter stage of the centrifugal cleaning plant. Before being fed to the latter stage, the feed consistency of the lighter fraction is increased.

Abstract: A debarking mechanism including a number of rotatable debarking shafts extending parallel to an advancing direction (A) of the trees to be fed therethrough, which are provided with a number of teeth extending beyond the circumferential surface of the shaft and the debarking shafts being adapted to each other in such a way that the presently processed trees make a circular motion (C) in the debarking mechanism, in which motion the trees are forced upon the support surface constituted by the debarking shafts effected by the rotary motion of the debarking shafts. The uppermost debarking shaft has been fitted together with a guiding surface, the surface together with the uppermost debarking shaft forming a slot convergent in the direction of rotation of the debarking shaft.

Abstract: Method and system for controlling the operation of a recovery boiler or another boiler having a furnace wherein the operation is monitored by monitoring sensors, the sensors converting the acquired electromagnetic radiation to electrical signals which are conducted to image processing which forms an image of an object, such as the char bed and/or the char and/or chemicals on the furnace walls and/or deposits on boiler surfaces, based on the data from the sensors, and wherein the operation, such as burning of the char bed and/or the formation of char and/or chemicals on the furnace walls and/or the formation of deposits on boiler surfaces, is controlled with help of the image, wherein the sensors are arranged to produce sensor signals for 3D (three-dimensional) imaging, wherein the sensor signals are conducted to the image processing unit for forming a 3D image, such as an image of the bed and/or the char and/or the chemicals, and/or its shape describing derivatives, and/or temperature chart of the bed surface

Abstract: An apparatus for screening a fibrous suspension including: a housing, conduits therein at least for fiber suspension being fed, reject and accept, and a rotor and a cylindrical screen drum installed in the housing, at least one of which is rotatable, whereby a surface of the rotor is provided with rotor elements in proximity to the surface of the screen drum, whereby each rotor element includes a front surface facing a flow of the fiber suspension, an upper surface and a trailing surface sloping from the upper surface towards the surface of the rotor, wherein the trailing surface of the rotor element is curved and sidewalls of the trailing surface converge at a back point of the rotor element.

Abstract: An apparatus for distributing a pulp flow, said apparatus including: a valve body connected to an inlet conduit and an outlet conduit for the pulp flow and provided with a closing member for opening and closing the valve to regulate the pulp flow; a distribution member arranged in a direction the pulp flow and downstream of the closing member, said distribution member distributing the pulp flow into at least two partial flows, and at least two channels wherein each channel receives a respective one of the two partial flows, wherein said channels are connected to the valve body or to the outlet conduit from the valve.

Abstract: The present invention relates to a method in connection with smelt removal form a recovery boiler, whereby the smelt is removed from the boiler via a smelt spout surrounded outside the boiler by a hood and a dispersion medium, preferably steam, is fed into the smelt flow falling from the smelt spout for shattering the smelt flow. An essential characteristic is that at least one wall of the hood is washed with liquid so that the liquid first flows downwards on the outer surface of the hood wall and is led into the interior of the hood via at least one trough-like member arranged on the outer surface of the wall and openings in the wall so that the liquid further flows downwards on the inner surface of the wall. The invention also relates to an arrangement for washing the hood and the feeding device for the dispersion medium.

Abstract: In a boiler, a space is reserved to expand the boiler by increasing the front and rear walls. To expand the boiler, wall additions are added to increase the width of the front and rear walls. After the expansion, the distance between the front and rear walls is substantially the same distance between the front and rear walls before the expansion.

Abstract: An arrangement in screening apparatuses of the pulp and paper industry, including a conduit for removing reject formed in a screening process. The circulation of material is arranged between the reject removal conduit and the interior of the screening apparatus from the removal conduit into the interior of the screening apparatus via a conduit external to the screening apparatus. When such a by-pass flow is arranged for pulp via external circulation, heavy particles in the layer being diluted are allowed to be separated onto the bottom of the reject removal conduit and therethrough e.g. into a separate junk trap.

Abstract: An apparatus for cleaning and cooling a liquor nozzle, the nozzle including at least a liquor tube for feeding liquor and chemicals into a furnace of a recovery boiler. The apparatus includes an outer casing tube, which defines a space whereto conduits are provided for introducing water and steam to generate an emulsion or a conduit for introducing emulsion generated by the water and steam and the surface of which is provided with openings, such as pores or holes, for discharging the emulsion formed by water and steam through the outer casing.

Abstract: A method for burning chlorine-containing liquors in a chemical recovery boiler at a pulp mill, wherein the recovery boiler includes spent liquor sprayers for feeding spent liquor and a number of combustion air levels including: increasing a combustion temperature in the recovery boiler in a burning zone where a chlorine-containing liquor or a chlorine-containing effluent is burned; while burning the liquor or effluent, volatilizing the chlorine in the liquor or effluent to produce chloride-containing salts in flue gases in the boiler, and removing the chloride-containing salts from the flue gases.