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).

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 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 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).

Abstract: A method and system for heating a hydraulic digester, such as a single-vessel hydraulic digester, which has a top separator, a level of chips and a liquid phase above the level of chips. The method includes: a. entraining chips in liquor to produce a slurry having a first temperature, b. feeding the slurry of chips to the digester through the top separator, c. supplying direct steam to the liquid phase between the level of chips and the top separator to heat the slurry to a second temperature for the impregnation stage, wherein the steam is fed by using at least one steam injector having a plurality of steam discharge openings; and d. heating the slurry to a third temperature and cooking the chips in a cooking zone, and withdrawing the cooked pulp from the bottom of the digester.

Abstract: A method and system for heating a hydraulic digester, such as a single-vessel hydraulic digester, which has a top separator, a level of chips and a liquid phase above the level of chips. The method includes: a. entraining chips in liquor to produce a slurry having a first temperature, b. feeding the slurry of chips to the digester through the top separator, c. supplying direct steam to the liquid phase between the level of chips and the top separator to heat the slurry to a second temperature for the impregnation stage, wherein the steam is fed by using at least one steam injector having a plurality of steam discharge openings; and d. heating the slurry to a third temperature and cooking the chips in a cooking zone, and withdrawing the cooked pulp from the bottom of the digester.

Abstract: The invention relates to an apparatus for mixing a gaseous or liquid substance into fiber suspension. The apparatus includes a tubular body, which defines a space that forms a flow channel for the suspension, in which body an inlet and an outlet for the suspension are arranged so that the suspension flows through the flow channel mainly in the axial direction. Further the apparatus comprises a feed member that extends into the flow channel transversely against the flow direction of the suspension and has a cylindrical wall provided with openings for leading the substance from the feed member into the flow channel. At least one protrusion is arranged on the inner surface of the tubular body in the region the feed member. A throttling member is arranged in the flow channel downstream of the feed member in the flow direction of the suspension, and a mixing chamber is formed in the flow channel between the feed member and the throttling member.

Abstract: The invention relates to an apparatus for mixing a gaseous or liquid substance into fiber suspension. The apparatus includes a tubular body, which defines a space that forms a flow channel for the suspension, in which body an inlet and an outlet for the suspension are arranged so that the suspension flows through the flow channel mainly in the axial direction. Further the apparatus comprises a feed member that extends into the flow channel transversely against the flow direction of the suspension and has a cylindrical wall provided with openings for leading the substance from the feed member into the flow channel. At least one protrusion is arranged on the inner surface of the tubular body in the region the feed member. A throttling member is arranged in the flow channel downstream of the feed member in the flow direction of the suspension, and a mixing chamber is formed in the flow channel between the feed member and the throttling member.

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: 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: A method and apparatus is disclosed for pumping a material, especially thick, gas-containing, fiber suspensions for wood processing. The apparatus includes a centrifugal pump with a rotor having blades twisted such that the pitch of the blade changes along the length of the rotor.

Abstract: A method and apparatus for heating cellulose pulp with steam are provided. Low-pressure (e.g. 3-5 bar (abs.)) steam is supplied into the pulp flowing as a plug flow in such a way that in the flow direction of the pulp, before supplying the low-pressure steam, the pulp is pressurized so that the pulp pressure at the point of the steam introduction is lower than the pressure of the available steam. After the steam is introduced the pulp is mixed with a pressure-raising mixer (such as a fluidizing centrifugal pump) to divide the steam evenly into the pulp and/or to equalize the temperature of the pulp.

Abstract: A method and apparatus for heating cellulose pulp with steam are provided. Low-pressure (e.g. 3-5 bar (abs.)) steam is supplied into the pulp flowing as a plug flow in such a way that in the flow direction of the pulp, before supplying the low-pressure steam, the pulp is pressurized so that the pulp pressure at the point of the steam introduction is lower than the pressure of the available steam. After the steam is introduced the pulp is mixed with a pressure-raising mixer (such as a fluidizing centrifugal pump) to divide the steam evenly into the pulp and/or to equalize the temperature of the pulp.

Abstract: A method and an apparatus for heating or cooling material having poor thermal conductivity, especially medium-consistency fiber suspensions. The material is directed, substantially as a plug flow, at a velocity below 5 m/s (e.g. 0.1-1 m/s) through an apparatus formed by a flow channel provided with heat exchange surfaces. The flow of the material is throttled at a throttling point by a more than 30% reduction in the cross-sectional area of the channel. After throttling, the material is discharged from the throttling point in such a manner that another portion of the material contacts the heat exchange surfaces.

Abstract: The present invention relates to a method and a device for mixing a second medium into a first medium. The method and the device according to the invention are particularly advantageous when used for mixing different chemicals, both liquid and gaseous, or steam into pulp suspension in the wood processing industry. In the method and device according to the invention, the first medium is fed into the mixer housing (10), mixed therein and removed from said housing (10), a freely rotatable rotor (20) being placed in said housing (10) and turned by means of the incoming medium flow into the housing (10).

Abstract: Gas is separated from fluent material, particularly a liquid or a cellulose fiber suspension having a consistency of about 8-18%, utilizing a closed separation apparatus having a spiral housing with a central axis, a fluent material inlet channel, a fluent material outlet, and a gas outlet. A pressure differential is maintained between the inlet channel and the spiral housing, and the pressure differential is converted to kinetic energy of the fluent material by causing the fluent material to flow through one or more spiral flow paths through the inlet channel toward the spiral housing. In the spiral housing a rotor is rotated to impart a strong centrifugal force to the fluent material to cause gas to separate and collect adjacent the central axis of the spiral housing, from which the gas is removed. The strong centrifugal force caused by the rotating rotor discharges the fluent material through the outlet. The spiral flow paths rotate with the rotor in the spiral housing.

Abstract: A method and apparatus allow large volumes of gas (at least about 10% by volume) to be mixed into a cellulosic fiber suspension having a consistency of about 8-25%. The mixing of ozone containing gas into the suspension is particularly desirable. The suspension is passed into the inlet of a mixer, gas is introduced into the mixer, and the gas and fiber suspension are homogenized by fluidizing the gas and suspension. The flow of suspension through the mixer is throttled so that the effect of the fluctuation and pressure between the inlet and outlet is minimized, and the homogeneously mixed gas and fiber suspension mixture is discharged from mixer outlet.

Abstract: The present invention relates to a mixing of gas into a medium. The method and apparatus in accordance with the present invention are especially applicable in the bleaching plants of the wood processing industry for mixing gaseous bleaching chemicals into pulp and to bleaching process of pulp, in which the mixing method and apparatus in accordance with the present invention are applied. An excellent application is mixing ozone-containing gas into a fiber suspension flowing in a pipe line and an ozone bleaching process. The previously known methods and apparatuses have not been able to mix satisfactorily large volumes of gas, about 50% of the total volume of the flow, into the medium flow.

Abstract: Gas is separated from fluent material, particularly a liquid or a cellulose fiber suspension having a consistency of about 8-18%, utilizing a closed separation apparatus having a spiral housing with a central axis, a fluent material inlet channel, a fluent material outlet, and a gas outlet. A pressure differential is maintained between the inlet channel and the spiral housing, and the pressure differential is converted to kinetic energy of the fluent material by causing the fluent material to flow through one or more spiral flow paths through the inlet channel toward the spiral housing. In the spiral housing a rotor is rotated to impart a strong centrifugal force to the fluent material to cause gas to separate and collect adjacent the central axis of the spiral housing, from which the gas is removed. The strong centrifugal force caused by the rotating rotor discharges the fluent material through the outlet. The spiral flow paths may be stationary or may rotate with the rotor in the spiral housing.

Abstract: A method and mixer are provided for mixing chemical (such as a gas like chlorine or oxygen) with a slurry (such as paper pulp having a consistency of about 1-16%) in such a way that separation of gas from the slurry at the discharge from the mixer is avoided. Where the mixer housing has a radial discharge, the leading and trailing walls of the discharge (in the direction of circular and tangential movement of slurry within the main body housing of the mixer) present curved configurations to transition the slurry from circular/tangential movement to radial movement. The curvature of the configurations (which may be provided by inserts) does not exceed an angle of about 10 degrees at any point along them until radial flow is established.