Abstract: The instant disclosure provides a continuous horizontal digester including a cylindrical pressure cooker capable of rotating by taking its central axis as an axis; a charging apparatus disposed at one end of the cooker which is communicated with an inner cavity of the cooker and can seal the cooker; and a discharging device disposed at the other end of the cooker and communicated with the inner cavity of the cooker, the discharging device is located on the central axis of the cooker. The continuous horizontal digester further includes a cooking device configured to cook the materials in the cooker.

Abstract: A drum structure, for a rotary drum filtering apparatus, comprising: a generally annular supporting drum, and a plurality of rib elements carried by the supporting drum longitudinally extending along the circumference of the drum generally in the longitudinal direction of the drum. A duplex stainless steel cover plate extends between two rib elements. A single supporting element supports the cover plate extending between each pair of two rib elements.

Abstract: A biomass hydrothermal decomposition apparatus includes, a biomass feeder (31) that feeds biomass material (11) under normal pressure to under increased pressure, a hydrothermal decomposition device (42A) that allows the fed biomass material (11) to be gradually moved inside a device main body (42A) from either end thereof in a consolidated condition, and also allows hot compressed water (15) to be fed from an other end of a feed section for the biomass material into the main body (42A), so as to cause the biomass material (11) and the hot compressed water (15) to countercurrently contact with each other and undergo hydrothermal decomposition, and that elutes a lignin component and a hemicellulose component into the hot compressed water, so as to separate the lignin component and the hemicellulose component from the biomass material (11); and a biomass discharger (51) that discharges, from the side where the hot compressed water is fed into the device main body, a biomass solid residue (17) under increased pr

Abstract: The method and arrangement are for adding treatment liquid to comminuted cellulose material, preferably wood chips, during the manufacture of chemical pulp in a continuous process. The process is using a down-flow vessel wherein chips are descending down the vessel in a plug flow and wherein treated chips are continuously fed out at the bottom of the vessel. By arranging at least one telescopic pipe inside the vessel that extends down into the plug flow makes it possible to adjust the position for the addition of treatment liquid depending on current operational parameters.

Abstract: A method to treat a lignocellulosic material including: performing a steam explosion reaction on the lignocellulosic material and discharging a slurry from the; adding an alkali material to the slurry in a first conveyor; transferring the slurry with the alkali material from the first conveyor to a second conveyor; adding an enzyme solution to the slurry while in, entering or at the discharge of the second conveyor; transferring the slurry with the enzyme solution from the second conveyor slurry to a mixer; mixing the slurry in the mixer, wherein a second portion of the enzyme solution is added to the slurry during the mixing, and transferring the slurry with the enzyme solution from the mixer to a first reactor vessel wherein the slurry in the first reactor vessel undergoing enzymatic hydrolysis such that the viscosity of the slurry is reduced in the first reactor vessel.

Abstract: A digestion apparatus is provided that include a vessel, a closure, and a fluid-transporting system. The vessel has a digestion chamber therein and an opening that provides access to the digestion chamber. The closure is adapted to interface with the vessel opening to form a fluid-tight seal against a digestion pressure and temperature within the chamber. The fluid-transporting system is adapted to direct fluid out of the digestion chamber back into the digestion chamber through an inlet port. The apparatus may include improved fluid heating, sample holding, safety and/or circulation options. Also provided are digestion methods that may use the digestion apparatus.

Abstract: A method for producing pulp by extracting hemicellulosic materials from lignocellulosic materials using water in an extraction stage, wherein the extraction stage is either a single extraction or a double extraction process; treating the lignocellulosic materials with an oxidizing agent in a treatment stage, wherein the treatment stage is selected from the group consisting of a second extraction process, an agent impregnation process, and a first pretreatment process; treating the lignocellulosic materials with a reducing agent in the treatment stage, wherein the treatment stage is selected from the group consisting of the second extraction process, the agent impregnation process, and a second pretreatment process; and then subjecting the lignocellulosic materials to a modified Kraft pulping process to produce pulp.

Abstract: Apparatus and methods for controlling the flow of a pulp suspension from a container in which the pulp is processed or stored are disclosed. The container is pressurized to a first pressure and includes an outlet for the pulp suspension, a pump includes an inlet and an outlet, and the pump inlet is connected to the container. The pulp suspension is fed from the inlet to the outlet of the pump and provides a controlled decrease in pressure to which the pulp suspension is subjected in the pump during such transport, and the flow from the container is controlled by adjusting this controlled decrease in pressure.

Abstract: The invention proposes an installation (10) in which the impregnation and fractionation of the raw material (MP) are conducted at atmospheric pressure, characterized in that it comprises means (18, 20) for transferring the raw material (MP) successively to a first treatment station (PT1) and a second treatment station (PT2), each comprising means (G1, G2) for temporarily combining, at the first station (PT1), the raw material (MP) with a quantity of a first mixture of organic acids and, at the second station (PT2), for temporarily combining the raw material (MP) with a quantity of a second mixture; and means, after impregnation, for at least partially recovering the quantity of second mixture after impregnation and for recycling at least a portion of the second recovered mixture to form at least partially said first impregnation mixture used at the first station (PT1).

Abstract: The vessel in which the chips are pre-treated with steam (ST) is provided with a ventilation channel at the top of the vessel for the leading away of weak gases to a weak gas system (NCG). A simple safety system has been installed with the aim of guaranteeing that these weak gases do not reach a level of concentration at which these weak gases become explosive. The safety system has a control unit (CPU) that detects a process parameter that is indicative of the fraction of moisture in the weak gases and opens dilution lines that supply air for the dilution of the weak gases in the ventilation channel. It is appropriate that the dilution take place in stages, where the dilution lines are opened in stages with successively increasing temperature of the weak gases.

Abstract: The invention relates to a method for processing waste paper according to the following steps: a) the waste paper is decomposed into fibres, b) the fibres are washed, c) the fibres are subjected to a dispersion process, d) the fibres are subjected to a flotation method, e) the fibres are processed for further treatment in a paper machine. The liquid from the fibres obtained in step b) is reintroduced into the fibre flow prior to step d). The invention also relates to a device for carrying out said method.

Abstract: Apparatus and methods for controlling the flow of a pulp suspension from a container in which the pulp is processed or stored are disclosed. The container is pressurized to a first pressure and includes an outlet for the pulp suspension, a pump includes an inlet and an outlet, and the pump inlet is connected to the container. The pulp suspension is fed from the inlet to the outlet of the pump and provides a controlled decrease in pressure to which the pulp suspension is subjected in the pump during such transport, and the flow from the container is controlled by adjusting this controlled decrease in pressure.

Abstract: The invention relates to a plant for producing hydrogen peroxide by direct synthesis (i.e. hydrogen reacts with oxygen in the presence of a catalyst), which is on-site at a paper mill. The invention relates to a method for manufacturing hydrogen peroxide by direct synthesis from hydrogen originating from the recovery of the spent liquor during the manufacture of wood pulp or cellulose pulp.

Abstract: A continuous digester comprises a wash zone having a plurality of individual wash screens disposed about an inner wall of the digester for the withdrawal of co-current downflow liquor from the wash zone. A conduit is connected in fluid communication between each of the wash screens and a collector for co-current downflow liquor withdrawn from the wash zone of the digester. A valve is interposed along the length of the conduit leading from each of the wash screens. The valve is operable between open and closed positions in response to a signal received from a temperature sensor associated with the conduit leading from each of the wash screens.

Abstract: A pulp digester includes a vessel having an inlet, an outlet and a wall extending between the inlet and the outlet, the wall of the vessel having a curved interior surface. The digester includes a screen assembly positioned inside the vessel adjacent to the curved interior surface of the wall for removing liquid from pulp material. The screen assembly is movable relative to the curved interior surface of the vessel wall. The digester includes at least one support element permanently attached to the vessel wall for limiting movement of the screen assembly relative to the curved interior surface of the vessel wall. In certain embodiments, the at least one support, such as a ledge permanently attached to the vessel wall, supports a portion of the screen assembly. The screen assembly may have an inner face that is concave in a horizontal direction and convex in a vertical direction.

Abstract: A method and an apparatus for processing wood chips, wherein the wood chips are treated with steam in a gas removal apparatus. The condensate formed in the gas removal apparatus is removed from the gas removal apparatus and the wood chips are treated with a processing solution in order to remove metal ions from the wood chips. Condensate formed in the gas removal apparatus is used as processing solution.

Abstract: A continuous digester comprises a wash zone having a plurality of individual wash screens disposed about an inner wall of the digester for the withdrawal of co-current downflow liquor from the wash zone. A conduit is connected in fluid communication between each of the wash screens and a collector for co-current downflow liquor withdrawn from the wash zone of the digester. A valve is interposed along the length of the conduit leading from each of the wash screens. The valve is operable between open and closed positions in response to a signal received from a temperature sensor associated with the conduit leading from each of the wash screens.

Abstract: A method and an apparatus for processing wood chips, wherein the wood chips are treated with steam in a gas removal apparatus. The condensate formed in the gas removal apparatus is removed from the gas removal apparatus and the wood chips are treated with a processing solution in order to remove metal ions from the wood chips. Condensate formed in the gas removal apparatus is used as processing solution.

Abstract: This invention is directed to a method for cooking wood chips in a digester for the separation of wood fibers from their bonded state, the digester having a vertical centerline, a substantially circular cross-section, and a wash zone adjacent the bottom end thereof and a plurality of individual wash screens disposed about the inner wall of the digester for the withdrawal of liquor from the wash zone. In the first step of the method, substantially equal volumes of liquor are dynamically withdrawn from the wash zone through individual ones of the wash screens, while monitoring of the flow rate of liquor exiting the digester through individual ones of the wash screens. The monitored flow rate is used to increase or decrease the flow rate from screens to a value substantially equal to the flow rate of liquor from the digester through each of the screens.

Abstract: Countercurrent extraction of lignocellulosic biomass such as trees, grasses, shrubs, and agricultural residues or waste involves the separation of cellulose fibers from other constituents, for subsequent use in the manufacture of paper, plastics, ethanol, and other industrial chemicals. Systems and methods involve continuous, multiple processing steps that may include chemical reactions with mixing at elevated temperature and/or pressure, efficient reagent or solvent utilization, filtration at elevated temperature and/or pressure, controlled discharge of liquid and solid products, and energy recuperation.

Abstract: A screen panel for a wood-chip digester, comprises a screen plate having a plurality of slots therein that are curved in the form of an arc. Each slot has a generally parallel-sided middle portion in the middle of the thickness of the screen plate, which middle portion has a width in the range of from 3 mm to 10 mm, and a portion that tapers out at an angle on each side of the middle portion, at a half-angle in the range of from 10° to 20°, for approximately one quarter of the thickness of the plate. All of the slots have their concave sides facing in the upstream direction of chip flow in the digester.

Abstract: A screen panel for a wood-chip digester comprises a screen plate having a plurality of slots therein that are curved in the form of an arc. Each slot has a width in the range of from 3 mm to 10 mm. One form of slot has a generally parallel-sided middle portion in the middle of the thickness of the screen plate, which middle portion has a width in the range of from 3 mm to 10 mm, and a portion that tapers out at an angle on each side of the middle portion, at a half-angle in the range of from 5° to 20°, for approximately one quarter of the thickness of the plate. Another form of slot tapers out from one side of the plate to the other side. All of the slots have their concave sides facing in the upstream direction of chip flow in the digester.

Abstract: A pulper for producing paper pulp from waste paper containing undesired scrap particles includes a container (1) forming a chamber (4) defined by a bottom wall (5) and a cylindrical circumferential wall (6). A paper tearing member (7) is arranged in the chamber closed to the bottom wall and is rotatable in a horizontal direction of rotation about the centre axis of the cylindrical wall. The bottom wall and the circumferential wall forms a substantially circular peripheral reject chute (11) situated under the paper tearing member for collecting reject including undesired scrap particles. The reject chute extends helically in the direction of rotation of the paper tearing member from an upper end (12) of the reject chute downwardly to a lower end (13) of the reject chute. The circumferential wall (6) has a substantially cylindrical shape and extends vertically to the reject chute (11). A discharge element (2) is adapted to discharge reject in batches from the reject chute.

Abstract: A system and method for feeding comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester provide enhanced simplicity, operability, and maintainability by eliminating the high pressure transfer device conventionally used in the prior art. Instead of a high pressure transfer device the steamed and slurried chips are pressurized using a single vane slurry pump in series with a centrifugal slurry pump both of which are located at least thirty feet below the top of the treatment vessel and for pressurizing the slurry to a pressure of at least about 10 bar gauge.

Abstract: A method to remove scale build-up in a vessel having at least one screen is described and involves placing a cover inside the vessel such that it is located beneath at least one screen to separate the screen from the rest of the vessel. The cover in the vessel forms an upper portion and a lower portion in the vessel. Preferably, the cover is in close proximity to the screen which is located in the upper portion of the vessel. The method then further includes introducing a chemical formulation into the upper portion of the vessel in a sufficient amount to remove at least a portion of the scale build-up on the screen. A system to remove scale build-up is also described and includes a vessel having at least one screen. The system further includes a cover located inside the vessel and beneath at least one screen to separate the screen from the rest of the vessel and to form an upper portion and a lower portion in the vessel. Normally the cover is in close proximity to the screen.

Abstract: Systems, methods, and vessels for reducing the stagnation and non-uniform flow or treatment of solid materials and slurries in vessels. The non-uniform flow or treatment that may characterize the storage or treatment of solid materials in process industries is minimized or eliminated by the introduction of liquid to the bottom heads of the vessels, in particular, the introduction of liquids in regions in the bottom heads where friction and compression cause stagnation in the flow of material. The liquid may be introduced by means of one or more nozzles, for example, one or more evenly-spaced nozzles, and the flow of liquid to each nozzle may be individually controlled. Though the systems, methods, and vessels disclosed may be used in the processing of cellulose materials, aspects of the present invention may be used in any process or materials handling industry application where solid materials or slurries are handled in vessels.

Abstract: A feed system for a cellulose pulp treating vessel (such as a continuous digester) is not limited by the required L/W ratio of the pump feeding a wood chip slurry to a high pressure transfer device, the feed system may be kept at a low temperature to minimize flashing of liquid into steam, and a return conduit from the treatment vessel to the transfer device high pressure inlet may be eliminated. Some of the liquid is removed from the slurry just before the low pressure inlet to the transfer device, and/or just after the high pressure outlet, to reduce the L/W ratio of the slurry by at least 0.25, e.g. from 3.0:1 to 2.25:1 just before the low pressure inlet, and from, 7.0:1 to 5.0:1 substantially immediately after the high pressure outlet.

Abstract: A system and method for improved filtrate addition in a continuous digester is disclosed. The system comprises a blow dilution header/nozzle assembly located in the blow dilution zone of the digester. The header/nozzle assembly comprises (i) a plurality of nozzles for introducing and distributing filtrate into the blow dilution zone, and (ii) a plurality of measurement and control devices for monitoring and controlling filtrate flow through the plurality of nozzles. The method comprises (a) introducing and distributing filtrate through a plurality of nozzles of a blow dilution header/nozzle assembly in the blow dilution zone of the continuous digester; and (b) measuring and controlling the filtrate flow through each nozzle of the plurality of nozzles.

Abstract: There is a process for making a cellulose ether. The process comprises the following: a) alkalyzing a cellulose pulp; b) etherifying the alkalyzed cellulose pulp to form a cellulose ether; c) washing the cellulose ether; d) drying the cellulose ether; e) milling the cellulose ether to a particulate form; f) heating the particulate cellulose ether; g) tumbling the particulate cellulose ether while simultaneously contacting it with an acid to partially depolymerize it to a lower molecular weight; h) partially or substantially neutralizing the acid. There is also an apparatus for making the cellulose ether.

Abstract: A process using an amphoteric ion-exchange resin, also known as a "snake-cage polyelectrolyte" resin separates kraft white liquor into sulphide-rich and caustic-rich components. The sulphide-rich component can be used in the initial stage of pulping, pretreatment of wood chips prior to pulping, or it can be used to make polysulphide-rich liquor. The caustic-rich component can be used in the final delignification phase, in place of sodium hydroxide or white liquor in oxygen delignification, pH adjustment and flue gas scrubbing. The same system can be used to separate green and polysulphide liquors into sulphide-rich and sulphide-poor components, and to remove sulphide from other mill caustic streams contaminated with sulphide.

Abstract: A method and apparatus for improving a batch cooking process, e.g. providing about 7% increase in discharge time, are provided. The invention is especially suitable for improving modern displacement batch cooking processes. A dedicated pump is mounted directly to each digester and discharges to a common superatmospheric pressure discharge tank.

Abstract: The invention relates to a valve arrangement which can preferably be used in connection with a removal system comprising digester screens for digester liquids in cellulose digesters. The valve is characterized by a housing (1) with inlet openings (7) for digester liquid from each screen and at least one outlet opening (5) for the digester liquid from the screens and also at least one inlet opening (8) for digester liquid intended for back-flushing the screens and a rotor (10) in the housing (1) which is designed to shut off intermittently at least one of the inlet openings (7) from the screens and instead open the latter for the liquid for back-flushing.

Abstract: A digester temperature distribution control system comprises an optical fiber type temperature measuring unit utilizing the Raman scattering effect, reference temperature measuring unit, reference point temperature setting unit, measured temperature distribution calculating unit, target temperature distribution calculating unit and control unit. The optical fiber type temperature measuring unit is provided in that digester charged with chips and equipped with control valves for controlling steam for heating the charged chip mass in the digester and is adapted to detect temperature at a plurality of points in a length thereof including a given reference point in the digester.

Abstract: A method of rehabilitating a wood pulp digester, comprising applying to an interior surface of the digester wall a tacky silicone rubber layer, and then applying vertical strips of metallic sheet material to form a composition layer of said silicone rubber and said metal strips.

Abstract: An apparatus for chemical treatment of lignocellulosic materials comprises two concentric compartments, the inner one is used for chemical reaction whereas the outer is used for generation of hot water or steam. The top and the bottom of the outer compartment is closed and connected to the inner one. These two are interconnected by two steam conduits. The inner compartment is also connected to a circulation pump and a heat exchanger. The bottom of this inner compartment is equipped with a quick-release valve which may be used to execute explosive discharge of the treated lignocellulosic material. On top of said apparatus is a cover which allows experiments to be performed under pressurized conditions. For experimentation, lignocellulosic material in form of chips (large particles) may be treated either with heated chemical solution or steam. Materials in form of fibers (fine particles) may be treated by means of vapor or by heat conduction furnished by the outer compartment.

Abstract: A cellulose pulp slurry is delignified in an apparatus comprising a vertical cylindrical barrel chamber, a cone-shaped bottom chamber connected to the barrel chamber and having a circular inlet formed in a lower end portion thereof, and a cone-shaped top chamber connected to the barrel chamber and having a circular outlet formed in a top end portion thereof, in which apparatus the cone-shaped top and bottom chambers converge at a convergence angle of 60 degrees or less respectively, by feeding a cellulose pulp slurry containing an alkali and oxygen and having a pulp consistency of 8 to 15% into the apparatus through the circular inlet of the bottom chamber at 70.degree. C. to 140.degree. C., and discharging the pulp slurry through the circular outlet of the top chamber, while controlling the flow speed of the pulp slurry in the barrel chamber to a level of 0.4 m/min or more.

Abstract: A method and system for cooling pulp discharged from a batch type digester and recovering heat from it. A stream of pulp together with spent cooking liquor is discharged from a batch digester to a diffuser and passed through the diffuser at substantially the same pressure as that of the digester. The pulp stream is caused to flow between screens and hot spent cooking liquor is displaced with cooler liquor flowing across the pulp stream thereby lowering the temperature of the pulp stream. The displayed cooking liquor and the pulp is withdrawn from the diffuser.

Abstract: A process and apparatus for producing pulp from impregnated cellulose-containing starting materials such as wood, straw, grass, waste materials etc. in a compacting apparatus comprising a shell (1) and two mutually opposite pistons (4, 4') contained in said shell. The material to be compacted is disposed between said pistons and constitutes a resistive electrical load. The pistons are movable relative to each other and the shell is movable relative to the pistons. The impregnated starting materials are digested at a relatively low hydromodulus of 0.5 to 2 with a direct action of heat on the impregnated starting materials in the compacting apparatus at a digesting temperature of 160.degree. to 300.degree. C. The digesting times are short and depend on the digesting temperature.

Abstract: A process and apparatus for producing pulp from impregnated cellulose-containing starting materials such as wood, straw, grass, waste materials etc. in a compacting apparatus comprising a shell (1) and two mutually opposite pistons (4, 4') contained in the shell. The material to be compacted is disposed between the pistons and constitutes a resistive electrical load. The pistons are movable relative to each other and the shell is movable relative to the pistons. The impregnated starting materials are digested at a relatively low hydromodulus of 0.5 to 2 with a direct action of heat on the impregnated starting materials in the compacting apparatus at a digesting temperature of 160.degree. to 300.degree. C. The digesting times are short and depend on the digesting temperature.

Abstract: A digester vessel for containing material to be subjected to a high temperature pulsating high pressure process with an inner tubular enclosing metal wall of a helically corrugated sheet material forming a chamber thereon, an outer containing tubular wall, and an intermediate layer of stacked ceramic material with a vent opening through the outer wall, mold bodies fitting the corrugation spaces between the inner wall and the intermediate layer, corrugated flanges at the ends of the inner wall welded to the outer wall, and an end closure for the chamber having a flange meeting a flange of the outer wall with a packing therebetween.