Abstract: A continuous and batch system to produce cellulose, native lignin and unicellular protein from any form of vegetation in a closed process. The biomass is mixed in the impregnate solution of nitric acid and/or ammonium hydroxide and water. After a period of time at room temperature and atmospheric pressure the chemical solution is recycled. The biomass is moved to the reactor and heated. Evaporated impregnate is recovered via absorption tower and recycled back to chemical solution. The biomass is moved to an alkaline solution, then cooled to separate pulp from black liquor. The black liquor is pumped to a separation tank and is treated to precipitate lignin. The solution is filtered to separate sweet liquor and lignin. The lignin is dried and the sweet liquor is fermented to produce unicellular protein.

Abstract: Methods for conveying, mixing, leveling, and flaking dewatered pulp to produce pulp flakes suitable to be used in a dryer. Methods for producing a consistent flow rate of pulp, and, for producing uniform pulp flakes in terms of pulp flake size and pulp flake moisture content. A method includes introducing a dewatered pulp to a rotating shaftless screw conveyor. The pulp is deposited from the screw conveyor onto a moving belt conveyor through a chute. The pulp is leveled with a rotary doctor located above the belt conveyor to produce a substantially even rate of mass flow of pulp along a length of belt conveyor. Uniform and consistent quantities of pulp per unit time can then be fed from the belt conveyor to a pulp flaker that then translates into an even rate of pulp mass flow to the dryer.

Abstract: The method and an arrangement are for improved impregnation of chips in association with the manufacture of chemical cellulose pulp. Un-steamed chips are fed into an impregnation vessel (30) in which a fluid level (LIQ_LEV) is established under the highest level (CH_LEV) of the chips. An improved impregnation arrangement for the chips is obtained by the addition of impregnation fluids (BL1/BL2/BL3) with increasing temperatures at different heights (P1, P2, P3), and by the establishment of a counter-flow zone (Z1) in the uppermost part of the impregnation vessel. The requirement for steaming may in this way be dramatically reduced while at the same time the amount of expelled waste gases may be minimized. A major part of the volatile compounds present in the wood are bound to the impregnation fluid (REC) that is withdrawn.

Abstract: The method is for bleaching cellulose pulp in a bleach line that has at least two bleaching steps. The filtrate distribution is led up through the bleaching line counter-currently to the flow of cellulose pulp established in the bleaching line. A single joint main conduit is used for the bleaching steps. Wash filtrates obtained from the wash steps, used after or before the bleaching step, are led in conduits to branch locations on the main conduit that are positioned downstream of the branch location for drawing off of wash and/or dilution liquor for the wash step in question. All branch points in the joint main conduit are in fluid communication with one another along the main conduit.

Abstract: The arrangement is for the adjustment of wear of the position of the rotor of a sluice feeder within a feed casing. The rotor has the form of a truncated cone and the play between the rotor and the surrounding casing is adjusted depending on the wear between the rotor and the casing through the rotor being axially displaced a predetermined displacement. A complete driving unit, motor and gear box are suspended on the journal of the rotor. The driving unit receives support from a torque support in the form of a beam fixed in the casing. The complete driving unit accompanies the rotor shaft during adjustment and makes contact with the torque-absorbing beam through sliding bearing supports.

Abstract: The digester and method are for the continuous cooking of pulp. At least two withdrawal positions (11E, 11D) for cooking fluid are arranged at different heights in the digester (10). The cooking fluid in the first and second position is withdrawn after the chips have had a retention time that differs by at least 10 minutes. The differential pressure between the positions is determined and when this exceeds a pre-determined level, a connection (17E) opens between these positions, establishing a flow parallel to a flow of cooking fluid between these positions in the digester. Several withdrawal positions are preferably connected in a common shunt system (17A-17F), with valves (18A-18F), controlled by the differential pressure, that are located between adjacent positions.

Abstract: A process for refining lignocellulose raw materials, especially wood chips, saw dust, annual plants or wood waste, includes dewatering the lignocellulose raw materials discharged from a digester, extracting condensate produced during dewatering, and refining the dewatered lignocellulose raw materials in a refiner.

Abstract: A continuous digester for producing chemical cellulose pulp from cellulose chips including: a digester vessel with an upper section attached to a top separator and said vessel at least partially filled with the cellulose chips and a liquor; a top separator at least partially in said upper section having a lower chip inlet port, a chip conveyor, a screen adjacent the conveyor, an upper chip discharge chute, and a liquor outlet facing a side of the screen opposite to the conveyor, and a chip inlet conduit extending into the vessel and having a first operational mode in fluid communication with the chip inlet port and a second operational mode in which the chip inlet conduit discharges directly into the vessel.

Abstract: A system for treating pulp comprises a dewatering device (2) for dewatering the pulp to a fiber concentration of at least 20%, a closed pulp-shredding vessel (16) for shredding the dewatered pulp, and an outlet pipe (22) from the pulp-shredding vessel. A transport screw (18) is arranged in the outlet pipe for transporting the shredded pulp from the pulp-shredding vessel through the outlet pipe through a reactor vessel (6) for bleaching the shredded pulp through reaction with ozone gas. The outlet pipe (22) is designed with a heightened roof portion (27), so that an upper gas space (29) free from pulp is formed in the outlet pipe between the roof portion and the transport screw. A flow-restraining member in the form of a partition wall (31) is arranged in the upper gas space in the outlet pipe for restraining the gas flow through the gas space, whereby the pumping action of the transport screw in the outlet pipe is decreased.

Abstract: The continuous digester is for producing chemical pulp to a process for operating this digester and to a feedback system for the cooking liquid. By means of implementing cooking zones 1st, 2nd, 3rd, 4th and 5th down through the digester, that have a successively decreasing liquid-to-wood ratio, it is possible to obtain a more uniform alkali profile during the cooking. The alkali is kept high at the beginning by means of a high liquid-to-wood ratio, typically over 6:1, which exceeds conventional liquid-to-wood ratios, which are normally around 3.5-5.0:1.

Abstract: The object of the invention is a method and a device for dispersing pulp, especially pulp containing waste paper, in which method ground pulp mass is fed between the blade surfaces (4) of a dispersing device that are brought in a rotating movement in relation to one another. The invention is characterized in that the dispersing event takes place in a narrow opening (5) between the conical surfaces (3) at the outlet end (6) of which there is arranged a running wheel (7) acting as pump by which the pulp is pumped out of the dispersing device by centrifugal force. The inner cone of the dispersing device may act as rotor and the outer cone may act as stator. In addition, the pulp may be diluted at the outlet end of the blade opening (5) with fluid introduced to the intake side of the running wheel (7).

Abstract: The invention concerns a simplified method for the continuous cooking of wood raw material in the form of sawdust for the production of cellulose pulp, The method does not require any thickening stages and can be carried out with a minimum of process equipment. The complete process can be established with a steaming vessel, a cooking vessel and a subsequent pressure diffuser while the sawdust is mixed with the cooking fluid to form a slurry. The slurry has a consistency that throughout the process does not exceed 20%. The maximum consistency is preferably held at a maximum consistency of about 15-17%.

Abstract: The method is for the manufacture of cooked cellulose pulp in which the starting material, preferably chips, undergoes a successive increase in temperature towards cooking temperature. This is done while the chips are first treated in a pre-treatment zone in which the main part, greater than 50%, of fresh white liquor necessary for the cooking stage is added, after which this alkali-rich treatment fluid is withdrawn and replaced to a major extent by black liquor. The alkali-rich treatment fluid that has been withdrawn after the pre-treatment stage is then added to the cooking stage, which is why the addition of fresh white liquor to the cooking stage is reduced to an equivalent amount. Maximal yield-enhancing effect is obtained using poly-sulphide-rich white liquor during the pre-treatment at a temperature in the interval 60±40° C. and retention time in the interval 2-60 minutes, preferably 2-10 minutes.

Abstract: The invention concerns a method for feeding chips into a chip bin or corresponding, the chips in said method being forced to move substantially horizontally as a plug filling the cross-section of the transfer space. The chip plug is formed and maintained at a part of the length of the transfer space with chips forced batchwise to the transfer motion.

Abstract: The invention relates to a feed arrangement for feeding chips to chip bins (1) in the production of cellulose pulp in continuous digesters (16), in which the chip bin is constituted by a treatment vessel having a top and a bottom, in which the chips are fed into the top (13) of the treatment vessel and fed out via the bottom of the treatment vessel using suitable lock members (10, 11). Distribution devices (4a, 4b) for the addition of steam are disposed in the treatment vessel so as to heat the chips to a level above 80° C., preferably around 100° C., when the chips are fed out via the bottom of the treatment vessel. By virtue of the fact that the chips are fed into the treatment vessel via at least one liquid lock (30) and the treatment vessel is otherwise sealed off, the quantity of driven-off gases from the chip bin is reduced to a minimum, at the same time as an effective utilization of available energy is obtained.

Abstract: A system for feeding fibres from a fibre separation step at a first pressure to a drying step at a second, lower pressure, the system comprising a sluice feeder (3) provided between the fibre separation step and the drying step. At least an outlet (14) of the sluice feeder (3) is enclosed by a housing (4) for pressurization by means of a pressure medium in the housing (4) to a pressure that essentially corresponds to the first pressure in the sluice feeder (3). The fed out fibre from the sluice feeder (3) to the housing (4) are removable by means of the pressure medium in the housing (4) via a control valve (20), which regulates the pressure in the housing (4), to the drying step at the second, lower pressure. The pressurization in the housing (4) prevents steam to escape from the sluice feeder (3).

Abstract: A continuous digester is disclosed for producing chemical cellulose pulp from cellulose chips, comprising: a continuous digester vessel having a lower section filled with the cellulose chips and an upper gas filled section; an inverted separator at least partially in said upper section which introduces chips and liquid into said digester vessel and separates some of the liquid from the chips, wherein said separator includes a drive shaft connected to a conveyor, and a liquid discharge port proximate to the drive shaft and arranged proximate to a chip discharge of the separator.

Abstract: A chip bin for a digester has an upper part through which chips fall freely from an inlet and a lower part within which the chips remain until they are fed to a digester. Steam orifices strike falling chips with steam and disperses the chips over the interior of the chip bin. Further steam heats the chips and drives out non-condensable gas. The lower part of the chip bin is conical. Steam jets aimed down the conical walls propel the chips to an outlet at the bottom and prevent bridging.

Abstract: An apparatus for carboxylating wood pulp which utilizes the wood pulp bleach plant and the method of carboxylating the pulp which takes place in the bleach plant.

Abstract: A process for producing microcrystalline cellulose. The process comprising the following steps: a) preparation of a pulp by repulping, b) pressing of the pulp obtained in a), c) decompaction of the pulp obtained in b), d) feeding of the pulp obtained in c) into a pre-heated reactor, e) cooking of the pulp at a temperature, a time and a pressure allowing to obtain a pulp having a desired degree of polymerization, f) cooling and partial controlled depressurization of the reactor by purging the reactor, followed by a water injection into the jacket and directly into the reactor, g) filtering the pulp obtained in f), h) bleaching of the pulp obtained in g), and i) drying the pulp obtained in h). The process allows the application of a controlled depressurization in step f), which in turn allows to keep the natural texture of the fibers and to obtain a cellulose having a low degree of polymerization.

Abstract: Process and container for stacking and diluting paper fiber stock. The process includes stacking a high-consistency stock in a first volume for defined dwell time, conveying stock to second volume arranged to adjoin downstream first volume, diluting stock in second volume at least to a pumpable consistency, and drawing off diluted stock as suspension through a wire. Process includes generating circulation flow in second volume, such that circulation flow facilitates conveying of stock located on boundary of first volume into second volume, diluting stock, and drawing stock through wire. Process includes rotating rotor to keep wire clear, and generating, with screw coil arranged directly in front of rotor, flow that runs in axial direction of screw coil and guides diluted suspension away from wire. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Abstract: A method and apparatus for treating pulp being fed into a blow tank or a storage tank. A preferred embodiment is that the pulp is discharged from a batch digester (10) and fed either to the upper or lower part of a blow tank (20), depending on the consistency of the pulp being discharged from the digester.

Abstract: Methods for producing chemical pulp from lignocellulose-containing material in processes for kraft pulp production are disclosed including charging the lignocellulose-containing material to a digester, initially treating the lignocellulose-containing material with an impregnation liquor, and then treating the impregnated lignocellulose-containing material with hot liquor and displacing calcium-containing spent liquor from the digester during that treatment, heating and cooking the heated lignocellulose-containing material to produce cooked lignocellulose-containing material and cooking liquor and displacing the cooking liquor from the digester using at least a portion of the displaced calcium-containing spent liquor.

Abstract: The method is for controlling the cooking temperature in a continuous vapour phase digester for chip-shaped cellulose material. A high pressure is established in the vapour phase largely by means of steam, without risk of attaining excessively high temperatures in the cooking. A temperature-controlled supply of cooking liquor in close proximity to the surface of the liquor level is introduced to obtain a protective liquor surface with a temperature lower than the vapour phase. A lower initial cooking temperature is obtained in the cooking zone, which ensures that the exothermic cooking process does not lead to the attainment of temperatures detrimental to the pulp quality.

Abstract: A system and process for the oxygen delignification of pulp consisting of a lignocellulose-containing material that has a mean concentration of 8-18% pulp consistency. The oxygen delignification takes place in a first stage with a short dwell time of about 3-6 minutes, at a low temperature of about 85° C. and under a low pressure of approximately 0-4 bar. A concluding stage has a longer dwell time of about 50-90 minutes, at a higher temperature of approximately 100° C. and under a higher pressure of about 8-10 bar.

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 continuous digester for producing chemical cellulose pulp from cellulose chips including: a digester vessel with an upper section attached to a top separator and said vessel at least partially filled with the cellulose chips and a liquor; a top separator at least partially in said upper section having a lower chip inlet port, a chip conveyor, a screen adjacent the conveyor, an upper chip discharge chute, and a liquor outlet facing a side of the screen opposite to the conveyor, and a chip inlet conduit extending into the vessel and having a first operational mode in fluid communication with the chip inlet port and a second operational mode in which the chip inlet conduit discharges directly into the vessel.

Abstract: The present invention is directed to a method and apparatus for fiberizing bales of pulp into substantially dry fibers and fiber aggregates, i.e., dry fluff, and metering the resulting dry fluff to a receptacle or other process, such as an airlaid process for making disposable absorbent articles.

Abstract: The invention relates to a continuous digester for producing chemical pulp, to a process for operating this digester and to a feedback system for the cooking liquid. By means of implementing cooking zones 1st, 2nd, 3rd, 4th and 5th down through the digester, having a successively decreasing liquid-to-wood ratio, it is possible to obtain a more uniform alkali profile during the cooking. The alkali which is totally available is kept high at the beginning by means of a high liquid-to-wood ratio, typically well over 6:1, which well exceeds conventional liquid-to-wood ratios, which are normally around 3.5-5.0:1. In combination with digester liquid from subsequent cooking zones being fed back to the top of the digester, the alkali concentration can be kept low at the beginning of the cooking, typically within 20-35 g/l when cooking softwood. This is achieved with essentially all the alkali, i.e. more than 80%, being added at the beginning of the cooking.

Abstract: A system for feeding fibres from a fibre separation step at a first pressure to a drying step at a second, lower pressure, the system comprising a sluice feeder (3) provided between the fibre separation step and the drying step. At least an outlet (14) of the sluice feeder (3) is enclosed by a housing (4) for pressurization by means of a pressure medium in the housing (4) to a pressure that essentially corresponds to the first pressure in the sluice feeder (3). The fed out fibre from the sluice feeder (3) to the housing (4) are removable by means of the pressure medium in the housing (4) via a control valve (20), which regulates the pressure in the housing (4), to the drying step at the second, lower pressure. The pressurization in the housing (4) prevents steam to escape from the sluice feeder (3).

Abstract: The invention relates to a method of mixing pulp components in the manufacture of paper, in which method the pulp components to be mixed are led to a mixing point along tubes arranged inside each other. The pulp component flows are mixed by generating turbulence in them by means of the end of an inner tube, the cross-section of which end is wave-like. This turbulence is guided and its effect is intensified by means of form parts in connection with the mixing point, which form parts are arranged on the inner surface of the outer tube. Further, the invention relates to an arrangement implementing the mixing of pulp components in accordance with the method.

Abstract: The present invention relates to a method of pretreating, by acidification and chelation, of pulp to be bleached with peroxide. Especially, the invention relates to intensifying, and at the same time simplifying the pretreatment required by peroxide bleaching. It is characteristic of the invention to introduce pulp into an acid tower (14, 112) where the pressure is 0 to 20 bar, preferably 1 to 10 bar, and the temperature 75 to 130° C. preferably 80 to 110° C., to treat the pulp in acid tower (14, 112) at a pH of 2 to 6, preferably 3 to 4, for 20 to 240 minutes, for decreasing the kappa number by 1-9, preferably 2-6 kappa units, to transfer the pulp from acid tower (14, 112) to a tower (24) of a second treatment stage, to treat the pulp with either a complexing agent at a pH of 4 to 9, preferably 5 to 6, or with an oxidizing chemical such as chlorine dioxide, Caro's acid, peracids or equivalent, and to wash and/or press the pulp.

Abstract: A method for producing chemical pulp from cellulosic material by means of alkaline cooking, including cooking the material to pulp at cooking temperature in a digester, reducing the temperature at the end of the cook, substantially relieving the overpressure in the digester and then discharging the pulp from the digester by means of pumping. The method is characterized in that the pulp is cooled to essentially 85° C. to 70° C. before pumping cooked material as a fluid suspension from the digester, and that the temperature of the cooked material is maintained in the same temperature range and at a pH level being between 10 and 13, between the digester and a first delignification/bleaching stage, thus avoiding mechanical damage of cellulosic material.

Abstract: A method for the continuous cooling of chemical pulp with the aim of achieving improved heat economy in a digester system comprising a vessel (1) for impregnation and a vessel (2) for cooking the impregnated cellulose chips. A part of the black liquor (14) withdrawn from the digester (2) is added at the beginning of a transfer system (4) having maintained essentially the withdrawl temperature, increasing the temperature of the chips mixture in the transfer system (4). A fraction of the transport fluid (10) from the transfer system (4) that is continuously withdrawn from the impregnated chips fed into the top of the digester is returned to the impregnation vessel (1) at essentially maintained transfer temperature, at a location before the said transfer system (4), seen from the point of view of the direction of flow of the chips.

Abstract: An apparatus and process for solvent pulping of cellulose-containing biomass utilizes at least one steaming vessel, a plug screw feeder or compression screw device, at least one super-atmospheric impregnation vessel, a solvent delignification reactor capable of operating at a pressure of 350 psig or more, and a solvent containing line for introducing solvent-containing liquor at the plug screw feeder outlet or compression screw device outlet. The process and system can also include at least one series connected pressure diffuser and optionally a retention tube downstream of each pressure diffuser to provide sufficient retention time to substantially preclude re-deposition of lignin on the cellulose fibers of the biomass, a blow tank connected to the last of the pressure diffusers and retention tubes, and vessels for multistage alcohol washing.

Abstract: The present invention relates to an arrangement in connection with bleaching pulp having a consistency of 7-20%, preferably 8-16%, said arrangement comprising a bleaching tower having at least one inlet opening and at least one outlet opening for pulp, a transfer line comprising a feed line operatively connected to the inlet of the tower and a discharge line operatively connected to the outlet of the tower, and at least one pump arranged in the feed line. The arrangement further comprises at least two propeller or turbine type devices for increasing the pressure of the pulp flowing in the transfer line.

Abstract: A method is disclosed for extracting liquor from a cellulose slurry for a continuous digester comprising the steps of: providing the cellulose slurry of liquor and chips of cellulose fiber material to a separator; extracting a first stream of liquor from the separator; extracting a second stream of liquor from the separator, where the second stream has an effective alkali (EA) concentration greater than the EA concentration of the first steam; outputting the first stream from the separator and outputting the second stream from the separator separately from the second stream, and outputting a condensed slurry from the separator to a digester vessel.

Abstract: A continuous pulp digester having an elongate horizontally aligned pressure vessel through which the wood chips and digesting fluid flow in a forward direction. In a first and second embodiments within the pressure vessel there is an inner container defining an elongate chamber or passageway having a square cross sectional configuration. In a third embodiment the digesting chamber is cylindrical. At locations along the digester, there are several pair of liquid flow inlets and liquid flow outlets which enable filtrate from a pulp washer and a digesting agent to be moved into and across the digesting chamber to flow out the flow outlets. These are recirculated in a net upstream flow pattern toward the outlet end of the digester, and discharged as black liquor at different locations in the digester.

Abstract: The flow of a liquid slurry of comminuted cellulosic fibrous material (e.g. wood chips) in a vertical vessel is made more uniform by providing a plurality of vertically spaced sets of either substantially continuous or discontinuous protrusions which extend inwardly from the internal surface of the vessel a maximum distance of between about 2-12 inches. A preferred vessel is a continuous or batch digester. The protrusions may have an arcuate, rectangular, isosceles or scalene triangular, right triangular, or trapezoidal cross-section, and may be spaced from each other vertically between about 1-12 feet, and have a height of between about 1-3 feet. Discontinuous protrusions have a preferred arcuate spacing of between 1-10 feet.

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 continuous digester is disclosed for producing chemical cellulose pulp from cellulose chips, comprising: a continuous digester vessel having a lower section filled with the cellulose chips and an upper gas filled section; an inverted separator at least partially in said upper section which introduces chips and liquid into said digester vessel and separates some of the liquid from the chips, wherein said separator includes a drive shaft connected to a conveyor, and a liquid discharge port proximate to the drive shaft and arranged proximate to a chip discharge of the separator.

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: A method is disclosed for extracting liquor from a cellulose slurry for a continuous digester comprising the steps of: providing the cellulose slurry of liquor and chips of cellulose fiber material to a separator; extracting a first stream of liquor from the separator; extracting a second stream of liquor from the separator, where the second stream has an effective alkali (EA) concentration greater than the EA concentration of the first steam; outputting the first stream from the separator and outputting the second stream from the separator separately from the second stream, and outputting a condensed slurry from the separator to a digester vessel.

Abstract: Processes and systems are provided for cooking wood chips containing knots in a digester to produce a chemical pulp. Specifically, a low pressure slurry of comminuted cellulosic fibrous material is formed in a vessel operating at essentially atmospheric pressure by mixing therein a liquid and the comminuted cellulosic fibrous material. The low pressure slurry is thereafter supplied to a low pressure inlet of a high pressure transfer device while liquid is removed from the slurry through a low pressure outlet thereof. A high pressure liquid is supplied to the transfer device (e.g., via a slurry pump) so as to form a high pressure slurry of the comminuted cellulosic material which is then discharged from a high pressure outlet of the transfer device. Knots are removed via a knot separator from a slurry of uncooked knot-containing cellulosic material at essentially atmospheric pressure.

Abstract: Processes and systems are provided for cooking wood chips containing knots in a digester to produce a chemical pulp. Specifically, a low pressure slurry of comminuted cellulosic fibrous material is formed in a vessel operating at essentially atmospheric pressure by mixing therein a liquid and the comminuted cellulosic fibrous material. The low pressure slurry is thereafter supplied to a low pressure inlet of a high pressure transfer device while liquid is removed from the slurry through a low pressure outlet thereof. A high pressure liquid is supplied to the transfer device (e.g., via a slurry pump) so as to form a high pressure slurry of the comminuted cellulosic material which is then discharged from a high pressure outlet of the transfer device. Knots are removed via a knot separator from a slurry of undercooked knot-containing cellulosic material at essentially atmospheric pressure.

Abstract: A pre-treatment device for wood chips for pulping comprises a tube through which the wood chips fall into a digester. Steam is injected into the tube through rings of nozzles, which are angled circumferentially to impart a rotary and turbulent motion to the falling chips. Some nozzles are angled downwardly to encourage the chips to flow freely through the tube, some are horizontal to encourage a longer dwell time near the nozzles. Digesting liquor is also sprayed onto the chips from spray nozzles after the first ring of steam nozzles. The heat and steam expel air and other non-condensable gases and volatiles from the chips, allowing them to absorb the liquor. At the bottom of the tube, the chips are propelled down and outwards by jets of higher-pressure steam, spreading and packing them into the digester.

Abstract: In the feeding of a slurry of comminuted cellulosic fibrous material to a digester (continuous or batch) in the production of chemical pulp, one of the tanks used in the feed system (which preferably includes a high pressure feeder) may be eliminated without consequent loss of its function by providing a single tank with the combined functions of controlling the level of liquid in a slurrying conduit which supplies slurry to a slurry pump, and storing and substantially continuously supplying liquid to a make-up liquid pump connected to the digester. The single tank preferably surrounds the slurrying conduit and is substantially concentric, and in liquid communication, with it. A gap of 3-48 inches may be provided between the bottom of the conduit and a connection to the slurry pump. A screen or strainer may be provided in the gap, which is substantially surrounded by the tank.

Abstract: In the feeding of a slurry of comminuted cellulosic fibrous material to a digester (continuous or batch) in the production of chemical pulp, one of the tanks used in the feed system (which preferably includes a high pressure feeder) may be eliminated without consequent loss of its function by providing a single tank with the combined functions of controlling the level of liquid in a slurrying conduit which supplies slurry to a slurry pump, and storing and substantially continuously supplying liquid to a make-up liquid pump connected to the digester. The single tank preferably surrounds the slurrying conduit and is substantially concentric, and in liquid communication, with it. A gap of 3-48 inches may be provided between the bottom of the conduit and a connection to the slurry pump. A screen or strainer may be provided in the gap, which is substantially surrounded by the tank.

Abstract: In the feeding of a slurry of comminuted cellulosic fibrous material to a digester (continuous or batch) in the production of chemical pulp, one of the tanks used in the feed system (which preferably includes a high pressure feeder) may be eliminated without consequent loss of its function by providing a single tank with the combined functions of controlling the level of liquid in a slurrying conduit which supplies slurry to a slurry pump, and storing and substantially continuously supplying liquid to a make-up liquid pump connected to the digester. The single tank preferably surrounds the slurrying conduit and is substantially concentric, and in liquid communication, with it. A gap of 3-48 inches may be provided between the bottom of the conduit and a connection to the slurry pump. A screen or strainer may be provided in the gap, which is substantially surrounded by the tank.

Abstract: In the feeding of a slurry of comminuted cellulosic fibrous material to a digester (continuous or batch) in the production of chemical pulp, one of the tanks used in the feed system (which preferably includes a high pressure feeder) may be eliminated without consequent loss of its function by providing a single tank with the combined functions of controlling the level of liquid in a slurrying conduit which supplies slurry to a slurry pump, and storing and substantially continuously supplying liquid to a make-up liquid pump connected to the digester. The single tank preferably surrounds the slurrying conduit and is substantially concentric, and in liquid communication, with it. A gap of 3-48 inches may be provided between the bottom of the conduit and a connection to the slurry pump. A screen or strainer may be provided in the gap, which is substantially surrounded by the tank.