Abstract: A method of purifying raw methanol obtained in chemical pulping, wherein heavy oil is admixed with the raw methanol to prevent precipitation, and the methanol mixture is distilled or evaporated to recover the methanol. The heavy oil is formed by mixing and heating raw methanol obtained from a side stream of chemical hardwood pulping with an acidic aqueous solution to vaporize low boiling point sulfurous compounds and provide acidified raw methanol. The acidified raw methanol is separated into a liquid top phase, a liquid aqueous middle phase, and a liquid bottom phase. The liquid bottom phase is extracted to obtain the heavy oil.

Abstract: According to an example aspect of the present invention, there is provided a method of removing volatile compounds from a lignin-containing material, the method comprising: providing a material comprising lignin and volatile compounds; treating the material by a distillation method in order to vaporize at least a part of the volatile compounds.

Abstract: A sealing arrangement (100) for a shaft, including at least a first seal element (10a) arranged around the shaft (30); at least a second seal element (10b) arranged around the shaft (30); wherein the first (10a) and second (10b) seal element include adjustable seal elements, wherein the first (10a) and second (10b) seal element include, respectively, an outer shell (14a,14b) of elastic material and a hollow core (12a,12b), wherein the hollow core (12a,12b) of the first (10a) and/or the second (10b) seal element is pressurized with a fluid for an adjustable sealing effect.

Abstract: A method for measuring mass changes of a heat exchanger bank (1, 2, 3) or the heat exchangers thereof of a steam boiler, which heat exchanger (4) is supported by hanger rods (7) to support beams (5,8) above the steam boiler, wherein at least one hanger rod (7) of at least one heat exchanger (4) is connected a lower measuring element (9) and an upper measuring element (10), and the changes of the measuring length (X) between the measuring elements (9, 10) is measured by a measuring instrument (15) connected between the measuring elements (9, 10) for measuring the mass changes of the heat exchanger (4). The measuring instrument (15) may be attached in between the measuring elements (9, 10) and the change in the measuring length (X) is measured by the deformation of the measuring instrument (15). A connecting member (11) parallel to the hanger rod (7) may be located between the measuring elements (9, 10), which connecting member (11) relays the change in the length to the measuring instrument (15).

Abstract: An arrangement for measuring the distance between at least one seal bar (20) and a rotating drum (10) of a drum displacement washer, including at least one sensor element (30) positioned inside the rotating drum (10) and configured to provide a signal indicative of the distance between the outer surface of the rotating drum (10) and the at least one seal bar (20); and a signal transfer element (50) configured to transfer the signal outside the rotating drum (10).

Abstract: A process for producing microcrystalline cellulose from fibrous cellulosic material by acid hydrolysis at an MCC plant. In this process a suspension of cellulosic pulp is thickened, so that filtrate is formed. A consistency of the thickened suspension is adjusted to 5-40% by adding dilution liquid, and the pH of the suspension is adjusted to a value of 4 or less with acid. The pulp suspension is subjected to acid hydrolysis of at least 120° C. in a reactor to produce a mixture of microcrystalline cellulose and hydrolysate. The mixture is discharged from the reactor to a lower pressure and lower temperature to flash the mixture and generate flash steam. Microcrystalline cellulose is separated from hydrolysate. The separated cellulose is washed in one or several washing apparatuses. The consistency of the microcrystalline cellulose is increased by thickening and/or drying for further processing.

Abstract: A method and system to determine one or more proportional particle group shares in flue gas of a recovery boiler (110) based on optical information gained from a flue gas sample. A processor (202) is used to read (301) a digital frame comprising the area under consideration, which represents at least a part of the surface of a sampler (120) kept in the flue gas flow of a recovery boiler. Particle group areas matching a color characteristic of the particle group comprised in the flue gas is determined (302) from the area under consideration. The joint area of the identified particle group areas is determined (304), and the share of the joint area from the total area is determined (305) as the proportional particle group share of the particle group.

Abstract: A centrifugal cleaner with a reject chamber (1) having a center dilution arrangement (3) with a dilution nozzle (4) to deliver dilution fluid to the reject chamber (1), and a reject outlet (7) at the bottom of the reject chamber (1). The dilution nozzle (4) points outwards to create a crossing outward flow of dilution fluid across an annular space (5) around the dilution arrangement (3) to slow circulating fluid flowing down from a cone (2) of the centrifugal cleaner to the reject chamber (1). The dilution arrangement (3) may have a clearing nozzle (6), directed against the reject outlet (7). The dilution nozzle (4) may be pointed below the bottom end (9) of the cone (2) and the dilution arrangement (3) may not extend higher than the bottom end of the cone.

Abstract: A system for automatic monitoring of smelt flow exiting a recovery boiler based on optical information. A processor is used to read at least one stationarily imaged video sequence, comprising digital image frames, including an area under examination representing at least part of the smelt flow exiting the recovery boiler. The processor is used to identify, in the area under examination, an area distinguishable based on colour and/or intensity information. The processor is used to determine, based on the identified distinguishable area, a monitored flow property of the smelt flow.

Abstract: A sealing arrangement for detecting thickness (t) of a sealing element (2) of a seal (1) wherein the sealing surface (3) at frontside of the sealing element (2) is arranged to be in sliding contact with sealed surface (4), wherein at least one sensor (5) measures the thickness of the sealing element (2) and is mounted to the surrounding component (10) of the sealed surface (4). The sensor (5) is positioned opposite the sealing element (2). The sensor (5) receives a response from a transverse border of the sealing element (2) or from an electrically conductive insert (6) or from an insert (6) of magnetic material, which insert (6) is embedded within the sealing element (2) or is connected to the backside of the sealing element (2). The thickness (t) is detected and/or measured along the length of the sealing element (2).

Abstract: An arrangement and a method for controlling a gas flow separated from a suspension of medium consistency pulp. The pulp is treated in a pulp treatment apparatus including a first pump and a second pump, wherein the second pump is a degassing centrifugal pump provided with a degassing system including a degassing conduit in which a degassing valve is arranged for regulating a pressure difference between an inlet of the second pump and the degassing conduit. The degassing system further includes a pressurized degassing vessel working under overpressure and having an inlet and an outlet, wherein the outlet of the vessel is connected to a pressure control valve for maintaining a desired overpressure in the vessel.

Abstract: A method to determine a reduction rate of a recovery boiler using optical information from a chemical smelt sample. A processor is used to read a digital frame at least part of which represents the chemical smelt sample of the recovery boiler. An area of interest is determined from the digital frame read comprising at least part of the area in the digital frame representing the chemical smelt sample. Of the pixel values of the area of interest, one or more spectral characteristic values correlating with the change of reduction rate are determined. The reduction rate of the recovery boiler is determined using a reduction rate function of one or more of the determined spectral characteristic values weighted at predetermined weights.

Abstract: An arrangement for installations of monitoring sensors of a vessel for treatment of lignocellulosic material, which vessel (1) has a central pipe (2) including at least one concentric pipe (3), mounted coaxially within the vessel (1). At least one sensor channel (4) is arranged along the outermost wall of the concentric pipe (3) of the central pipe (2) and that the at least one sensor channel (4) is connected to a cable conduit (5), which cable conduit (5) connects the exterior of the vessel (1) to the at least one sensor channel (4)) and the sensor channel (4) is several meters long and has plurality of holders (13) for sensors (11) and/or is configured to contain plurality of thermal sensors (11) with their cables (8).

Abstract: According to an example aspect of the present invention, there is provided a method for producing an oxidised lignin based high performance surface active agent in techno-economically feasible manner within kraft pulp mill without interfering the main process.

Abstract: A method for feeding a slurry of chips and liquid to a prehydrolysis reactor in the production of dissolving pulp. The slurry is pumped by using at least one pump to the reactor, and alkali is fed into the at least one pump 5 for adjusting the pH of the slurry to a range of 7-10.

Abstract: A method of treating fly ash containing sodium sulfate from a recovery boiler of a chemical pulp mill. This method includes at least the following steps: a) ash is dissolved in an aqueous solution and the pH of the solution is adjusted with alkali for precipitating impurities, b) the solution is filtered for removing the impurities containing precipitate, c) sodium sulfate is crystallized from the solution and the crystals are separated from the solution by filtering or by centrifugation, and d) the crystallized sodium sulfate is used as initial material for producing sodium and sulfur containing chemicals or as process chemical.

Abstract: A method for controlling discharges of nitrogen compounds in the production of cellulose carbamate (CCA). Microcrystalline cellulose is produced from chemical pulp produced at a pulp mill, such that the chemical pulp is subjected to acid hydrolysis at an elevated temperature to form microcrystalline cellulose (MCC) and hydrolysate, and the MCC is reacted with urea to produce cellulose carbamate whereby ammonia is released. The microcrystalline cellulose production and the cellulose carbamate production are integrated into the pulp mill having a flue gas system such that carbon dioxide from the flue gases is reacted with released ammonia to produce urea, which is used in the carbamate production.

Abstract: A transmission wheel assembled of at least two segments (1) on a shaft (12), the inner arc surface (3) of which and the shaft (12) have essentially the same radius (R), and which segments' (1) outer surfaces (9) have profiled surfaces that transmit the power of the transmission wheel. Between the segments' (1) welded-together end faces (4) there are gaps on those sections of the end faces (4) that are not welded, which creates a press fit between the shaft (12) and the inner arc surface (3) of the transmission wheel. The weld connecting the transmission wheel segments' (1) end faces (4) may be incomplete, meaning that it does not reach the shaft (12).

Abstract: A method of producing chemical pulp including at least the following steps: a) wood chips or other comminuted ligno-cellulosic fibrous material is treated with a polysulfide-containing cooking liquor in an impregnation stage at a temperature of 90-145° C., and b) slurry of fibrous material from step a) is heated into cooking temperature and cooked for producing pulp having a desired kappa number. After step a) mercaptide ions are added into the slurry of fibrous material and the fibrous material is treated at cooking temperature in step b).

Abstract: A separation device having a housing (10) with a feed conduit (1) and a reject conduit (2), between which conduits (1, 2) and an accept conduit (3) of the housing (10) is a rotor unit (13) having a shaft (4) transverse to the through-flow direction of the separation device, which shaft rotates discs (5) attached to the shaft (4), the outer surface and/or side surfaces of which discs are jagged, i.e. they have protrusions (6) and/or notches and/or these surfaces are substantially rough and the teeth (9) of at least two sieves (7, 8) attached to the housing (10), extend between the discs (5), the first sieve (7) being between the reject conduit (2) and the accept conduit (3) and the second sieve (8) being between the feed conduit (1) and the accept conduit (3).