Abstract: An apparatus and method for use in a batch digesting process to quantitatively displace fluids in the digester by pumping into the digester under pressure a first volume of displacing fluid at the upper end and a second volume of displacing fluid at the lower end of the digester. Displaced fluids are collected and removed form the digester near the midline between the top and the bottom of the digester.

Abstract: Extended delignification of kraft pulp in a pressure diffuser allows a pulp mill with a digester (e.g. continuous digester) to increase its production capacity without building a new line, or to decrease its demand in its bleach plant, or to increase the strength of softwood pulp it produces. Comminuted cellulosic fibrous material is kraft cooked to produce kraft pulp having a blow temperature over about 300.degree. F. The pulp is diffusion treated in the first stage of a pressure diffuser to replace the water around the pulp with delignifying liquor. The liquor has a dissolved lignin concentration of less than 12% (optimally less than about 4%), has an effective alkali concentration of at least 2 gm/l (preferably 8-55 gm/l), and a temperature of at least about 300.degree. F. Treating the pulp with the delignifying liquor significantly reduces the K-number (e.g. on the order of about 5). After extended delignification, the pulp is washed in subsequent stages of the pressure diffuser.

Abstract: A batch process and mechanism for cooking fibrous paper pulb including a digester wherein the pulp is cooked under elevated temperatures and pressures for a predetermined time, a discharge line leading from the lower end of the digester to a blow tank, a valve in the discharge line and cycling means connected to the valve cyclically opening and closing the valve while the contents are emptied from the digester.

Abstract: Mechanical cellulosic fibrous material pulp (mechanical pulp to produce paper products) having lower freeness, and enhanced light scattering properties, tensile and tear strengths, for a given energy input, is produced by force feeding a refiner. Using a progressive compacting plugscrew, cellulosic material (e.g. wood chips) is fed to the refiner inlet at a rate greater than the transporting capacity of the refiner (e.g. about 10-40% greater). The refiner preferably is a low frequency conical refiner with steam removal at the grinding area between the conical refiner elements. The production rate is regulated by sensing the axial force on the refiner rotor and controlling the spacing between the refiner elements in response to the sensed axial force. The screw has a compaction ratio of at least 3/1 for wood chips and 6/1 for pulp, and is rotated at about 6-10% the speed of rotation of the refiner rotor.

Abstract: A pumping system is capable of handling a paper pulp suspension of medium consistency (e.g. about 8-15% solids consistency) utilizing a conventional centrifugal pump. A conventional pump system capable of handling 3-8% consistency pulp may be retrofit to handle 8-15% consistency pulp. A tube with vanes, and having an open end, extends through the inlet to the pump so that there is a small clearance between the vanes and the inlet, and so that the open end is adjacent but spaced from the hub of the pump impeller. A gas passage extends from the hollow interior of the tube to an area remote from the pump. The tube is rotated in a direction of rotation opposite to the direction of rotation of the pump impeller, and at a speed sufficient to fluidize pulp of about 8-15% consistency, and to force the pulp toward the pump. Gas which collects at the pump impeller is withdrawn through the tube and a gas passage in a shaft connected to the tube, and for that purpose a vacuum pump may be utilized.

Abstract: The present invention relates to a method of intensifying the washing of a fiber suspension. In particular, the present invention relates to decreasing the lignin content of a fiber suspension by extracting. Lignin removal is usually carried out at a consistency of less than 3% whereby heating consumes much energy. The method of the invention allows a considerable increase in the consistency of the suspension which results in that the energy consumption is decreased to a fraction of the one required by prior art methods. A characteristic feature of the method of the invention is that dry substance and chemicals contained in the fibers are extracted at a raised pressure and temperature.

Abstract: A method of preparing a pulp for digestion in a continuous process from a fiber-containing cellulose material is described.

Abstract: Method for transferring fibrous materials transportable with a liquid between various treatment stages, preferably from digesting (10-16) to a subsequent treatment (38) by means of circuits of circulating liquid. Material from one or several discontinuous treatment steps (10-16) are supplied to a subsequent continuous treatment step the material being fed into the continuous step (38) by displacement by means of a liquid portion (36) withdrawn from the said step.

Abstract: Resin is removed from mechanical pulps, such as TMP, CTMP, and the like, in a quick and simple manner. Mechanical pulp at a consistency of about 7-20 percent (preferably 8-15 percent) is subjected to high turbulence. The high turbulence may be effected by fluidizing the pulp, as in a centrifugal fluidizing pump, or otherwise by subjecting it to high turbulence as in a mixer, screen, or disc mill refiner. By subjecting the pulp to high turbulence treatment for a time period of about 0.2-10 seconds, resin removal is greatly enhanced, and in subsequent dewatering of the pulp a pressate is formed which has a higher concentration of resin in the pressate than in pressates produced by conventional processes. After dewatering the pulp is preferably diluted (again to about 7-20 percent consistency), and the turbulence and dewatering steps are repeated. Chemicals to improve deresination can be added to the pulp while it is subjected to high turbulence.

Abstract: Oxygen delignification of paper pulp (comminuted cellulosic material in a slurry) at medium consistency (i.e., about 6-18%) is practiced without the necessity of a separate mixer. The pulp is drawn into the inlet of a fluidizing centrifugal pump capable of pumping medium consistency pulp. The pump typically has a vacuum system associated with it for effecting degassing of the pulp. As the pulp is pumped out of the pump outlet, oxygen gas is added to the pulp. This is accomplished utilizing a shear plate having a central opening and one or more radial bores, oxygen being introduced under pressure into the bores to pass into the pulp flowing through the plate central opening. A tube may be disposed in the bore(s) and have an oxygen permeable portion (such as a porous stone or sintered metal) extending into the central opening in the plate, the oxygen being introduced in the form of very small bubbles by the oxygen permeable portion.

Abstract: A chemical pulping process is disclosed wherein wood chips are partially defiberized such that the fibers in the chips are substantially separated from one another but sufficient interfiber bonding is maintained to preserve chip integrity and thereby provide chips having an open porous fibrous network; and the chips are subjected to chemical pulping at an elevated temperature to remove a majority of the lignin in the chips.

Abstract: Apparatus for feeding wood chips and the like into a treatment bin includes a feed tube assembly adapted to lead into the bin at a non-zero angle relative to the horizon. A plate is supported underneath the lower end of the feed tube assembly to collect in a mound wood chips fed through the feed tube. The height of the lower end of the feed tube assembly is adjusted so that the lower end of the feed tube assembly engages the mound of wood chips and thereby forms a seal with the mound. A plow is supported between the plate and the lower end of the feed tube assembly. Either the plate is stationary and the plow rotates or the plow is stationary and the plate rotates to knock wood whips from the mound off the plate. The apparatus optionally includes a feed screw mounted within and longitudinally of the feed tube assembly to compress the wood chips into the mound.

Abstract: Bamboo can be formed into a suitable pulp if prior to digestion it undergoes a process of shredding, washing and wet depithing. The fibers are then chemically digested preferably by a process which uses rapid pressure drops to open the fibers using the energy contained in the wet superheated fibers.

Abstract: Lignocellulosic material, after delignification in an alkaline pulping liquor, can be removed from the digester in which it was pulped by first cooling the cooked material and relieving the overpressure from the digester, and then pumping the cooked material from the digester to a receiving vessel as a fluid suspension in spent liquor. When the fluid suspension is pumped at a low flow rate, the pulp thus obtained is superior in its physical properties to pulped material which is discharged under conventional conditions of high pressure and high flow rate from batch or continuous digesters.

Abstract: A method and apparatus for continuously treating cellulosic chips to prevent degredation of the chips as a result of mechanical action exerted on the chips by a scraper. A false bottom is provided in a vessel with the scraper mounted for rotation about a vertical axis just above the false bottom, a large central opening being provided in the false bottom. The scraper removes chips from the vessel through the false bottom opening to a bottom portion of the vessel. The temperature within the vessel at the area of the scraper is maintained at a first temperature that is low enough so that loss of strength of the chips material does not result from mechanical action exerted on the chips by the scraper. Liquid is introduced into the vessel bottom portion at a second temperature that is approximately at the cooking temperature for effecting digestion of the chips, and substantially higher than the first temperature.

Abstract: A method and apparatus are provided for effecting presteaming and deaeration of wood chips, or like comminuted cellulosic fibrous material. Presteaming takes place in a vertical presteaming vessel, utilizing a plurality of uniformly radially spaced nozzles adjacent the bottom of the vessel, a plurality of generally uniformly radially spaced steam introduction pipes in a central portion of the vessel, and a pair of synchronized rotating valves for feeding steam to the introduction nozzles and pipes in a coordinated manner. After presteaming, the chips pass through a chips meter to a vertical chute in which they are entrained in liquid, and then pass to a horizontal deaerating vessel. In the deaerating vessel, deaerated liquid is passed in a path generally perpendicular to the path of the material flowing through the deaeration vessel.

Abstract: Immediate and accurate control of a pulp refiner is provided so as to control the degree of refining in the production of mechanical pulp, such as RMP, TMP, and CTMP. The mechanical pulp discharged from a refiner is fluidized by a fluidizing centrifugal pump, the fluidizing action instantaneously removing the pulp latent properties. A sample of the latency-removed pulp is then subjected to a pulp freeness measurement, and that freeness measurement is supplied to a computer. The computer utilizes the freeness measurement, as well as other measurements such as pulp consistency and flow rate measurements, and dilution flow measurements, and in response to the inputs control refiner parameters to ensure that the freeness of the mechanical pulp being produced is within the desired range. The refiner parameters controlled can be the hydraulic plate loading (refining pressure), and/or the tonnage of fiber supplied to the refiner.

Abstract: The latency of mechanical pulp is removed in a quick and simple manner. After refining of comminuted cellulosic material to produce mechanical pulp, the pulp is diluted (if necessary) to a consistency of between about 8-25%, and the pulp is then merely pumped to a further treatment stage. Pumping is effected utilizing a centrifugal pump which fluidizes the pulp, the fluidization imparting sufficient energy to the pulp to remove the latent properties. The pulp may be pumped to a storage stage prior to passage to a screening stage, and can be pumped in a direct (non-return) path from the pump to the screening stage. If desired or necessary, a portion of the pumped pulp can be recirculated and pumped again to ensure that sufficient energy is imparted thereto to effect latency removal.

Abstract: Comminuted cellulosic fibrous material, such as wood chips, are treated in a continuous digester to produce paper pulp or the like in a manner providing completely uniform treatment of the chips. The chips are introduced in a feed liquid slurry into the top of the digester, with a swirling action, and establish a vertical column in the digester having a substantially horizontal top, with some liquid between the top of the digester and the top of the chips. Below the top of the chips the feed liquor is withdrawn through a first set of withdrawal screens, and recirculated to entrain other chips to feed them to the top of the vessel. At other vertically spaced areas of the digester other screens are provided for withdrawing, cooking, quench, washing, and like liquors, and effecting recirculation thereof. At each screen set a plurality of nozzles are provided circumferentially spaced around the digester, each nozzle cooperating with only a particular radial segment of the screens.

Abstract: A method provides for the continuous treatment of a porous, fibrous material such as paper pulp, with a gas, such as ozone. The material is entrained with gas and passed in a first path. The material and gas move in a path defined by a downwardly curved upper wall and an open bottom, with a baffle disposed adjacent the bottom termination of the downwardly curved wall, so that the material is separated from the gas, the material flowing in a second path and the gas in a third path, distinct from the second path. The material in the second path is moved so that it intersects the flow of gas in the third path at least once, with the gas passing through the material while remaining in the third path, until the desired treatment of the material has been achieved. Preferably the second path is a serpentine path including horizontal portions, and the third path is a substantially straight downward path. After treatment, the material is discharged in a fourth path, and the gas passes along a fifth path.

Abstract: A process is provided for the removal from paper pulp of impurities, the pulp being contained in a pulping machine. Some of the pulp is periodically transferred into an enclosed chamber annexed to the pulping machine, the chamber having a volume which is small compared to the volume of the pulping machine. The pulp in the chamber is stirred and separated by a rotor, and fibre suspension is returned to the pulping machine, dilution water being introduced into this chamber. The chamber is emptied and impurities thereafter discharged.

Abstract: A method and system for recovering heat in a pulp digesting process is disclosed. The method includes the steps of blowing a pulp and liquid mixture from a digester to a container such as a blow tank or blow cyclone; transferring flash vapor above a predetermined pressure, which is above atmospheric pressure, from the blow tank to a pressure accumulator; transferring flash vapor below the predetermined pressure from the blow tank to an atmospheric accumulator; and mixing the flash vapor with a processing liquid in the pressure accumulator.

Abstract: There is disclosed a process for the transfer of fiber material from one circuit of circulating liquid to another, where the fiber material is transported by circuits positioned at right angles to the axis of rotation of a rotary transfer or feed valve and the circulating, transporting liquids are screened off through self-cleaning screens. The transfer valve contains a pocket and three working positions, a filling circuit, an emptying circuit, and an intermediate position for preheating the fiber material or providing a temperature lock depending upon the rotation of the pocket.

Abstract: A process for producing alkali pulp by using a single, cylindrical pressurized reaction vessel having therein a liquor-inpregnating zone, a cooking zone, a washing zone, and a diluting zone in that order, and having a motor-driven scraping or agitating device and a pulp discharging outlet in the end portion of the diluting zone. Alkaline aqueous medium containing dissolved oxygen therein is introduced into the diluting zone. A part of the introduced alkaline aqueous medium countercurrently contacts cooked cellulosic materials transferred from the washing zone to the diluting zone to proceed with oxygen-alkali delignification, and is finally discharged out of the vessel from the end portion of the cooking zone.

Abstract: A process for continuously monitoring and controlling a continuous process for digestion of cellulose utilizing a computer which is programmed to determine (1) the mass of wood being fed to the digester from measurements of the density of the wood slurry feed, the density of the liquid and the total flow of slurry, (2) the mass of wood being withdrawn from the digester from measurements of the density of the pulp slurry, the density of the liquor and the total flow of slurry, (3) the correct amount of fresh digester liquor to be added concurrently with the wood feed and (4) amount of water wash and makeup digester liquor to be fed to the reactor. The computer can also be programmed to control the temperature in the reaction zone of the digester.

Abstract: Lignocellulose is pulped batchwise by introducing it and the white liquor in predetermined quantity, together with a variable quantity of black liquor, into a continuously steam pressurized digester. When the cooking cycle has been completed, the pulp product is withdrawn. The time intervals of feed material introduction and pulp product withdrawal are correlated to insure that all of the lignocellulose charged to the digester is cooked uniformly, as by withdrawing the pulp product over a time interval which is substantially equal to the feed time. For economy and efficiency of operation, the digester preferably is operated in conjunction with one or more companion digesters to which it is connected. The first digester then is blown while a second digester is charged, making possible transfer of hot pressurized black liquor from the former to the latter.

Abstract: A method and apparatus for continuously hydrolizing finely comminuted cellulosic fiber material and separately extracting the acid hydrolysate therefrom. Cellulosic material is fed into an upright elongated reaction vessel near the upper or top portion thereof and heated to hydrolysis temperature. The heated fiber material then passes downward through the reaction vessel and is concurrently treated by exposure to a short liquid phase which comprises concurrent impregnation and simultaneous concurrent hydrolysis to partially hydrolize the fiber material. The material is then exposed counter-currently to a liquid phase comprising a counter-current wash with simultaneous hydrolysis of a wash liquid which has been introduced from the bottom or lower portion of the reaction vessel, the wash liquid having been preheated to full hydrolysis temperature.

Abstract: A method and apparatus for continuous oxygen bleaching of cellulosic pulp is provided utilizing first and second pressurized chambers with a number of tubes in fluid communication with both of first and second chambers. Oxygen bearing fluid is intimately mixed with digested cellulosic pulp and is continuously fed under pressure to the first chamber. Communication is selectively provided between the first and second chambers through at least one of the tubular members to allow passage of pulp from the member to the second chamber. The tubular member through which pulp flows to the second chamber is progressively changed as are the members through which passage is blocked, so that the pulp remains within each tubular member sufficient time to allow oxygen-bleaching thereof without degradation, and passes through the members without channelling. The oxygen bleached pulp is continuously discharged from the second chamber. The passage of pulp through the tubular members may either be downwardly or upwardly.

Abstract: A method for continuously digesting cellulosic fiber material so that the digested pulp has a very low quantity of reject material (i.e. one to two percent) compared to the prior art. Fiber material is continuously fed into a standing vessel downwardly through the vessel steam phase to establish a fiber level, digesting liquid being added to the vessel to maintain a liquid level therein, and the digested pulp being withdrawn from the bottom of the vessel. Spreading of the downwardly flowing fiber material in the steam phase substantially evenly over the vessel cross-section is effected and the downwardly flowing fiber material is heated by introducing a major portion of the steam to be introduced into the steam phase at a first vertical position about 0.0 to 100 cm. above the higher of the fiber and liquid levels in the vessel.Some of the steam may be added at a second vertical level, or at a third vertical level.

Abstract: A control system and a process is disclosed for a continuous wood chip downflow digestion system. The system maintains chip level in the top of the digester and maintains a consistency in the ratio of chips to liquor in the blowline thus allowing the system to run without constant operator attention. The system comprises a means for measuring the level of chips at the top of the digester and producing a level index over a predetermined time. This level index is compared with a preset level index and an error signal produced which operates a speed control means within preset limits for a rotating scraper feeding into the blowline. There is also provided a means for measuring the feed rate of chips to the digester, and a summating means for adding a predetermined ratio setpoint for the feed rate of chips against a flow in the blowline, to an integral of the error signal above or below a preset range to produce a summated ratio.

Abstract: Cooked pulp at an elevated temperature and pressure is discharged from a plurality of batch digesters sequentially into a first blow tank. The first blow tank is maintained at a substantially constant pressure which is less than the pressure in the digester and greater than atmospheric. Pressurized steam is released from the first blow tank into a dirty steam system as pulp is discharged into a second blow tank at a substantially constant rate in a non-interrupted flow stream. The pressure in the second blow tank is maintained at about atmospheric pressure. A blow line refiner is interposed between the first and second blow tanks.

Abstract: A process and apparatus for automatically maintaining the moisture content in a continuously conveyed batch of porous materials is described. The porous material is continuously fed through a treatment tank, wherein it is contacted with a liquid to be absorbed therein. The moisture content of the material is continuously monitored as a direct function of the combined weight of the material and the treatment tank to generate correction signals. The correction signals are utilized to vary the dwell times (up or down) of the porous material in the treatment tank. By varying the dwell times the porous material is contacted by the treating liquid for either larger or shorter periods until the weight of the tank and material therein returns to the weight desired. Thus, the moisture content of the porous material is continuously adjusted to a substantially constant value.

Abstract: Apparatus for electroslag remelting of at least one consumable electrode in a cooled mold assembly with a cooled bottom plate having mechanism accomplishing relative movement between at least a part of the mold assembly and the ingot being formed during forming of the ingot. Movement of selective parts of the mold assembly relative to the ingots and/or the electrode is provided with or without movement of the electrode itself. Structure for bottom pouring of molten slag is provided. A specified mold assembly has, as an element, a cooled core device enabling making hollow ingots, in which case the hollow core device can be moved axially, reciprocated axially and reciprocally rotated during forming of the ingot. Electrical power for the electroslag remelting can be connected between the consumable electrode and any or all elements of the mold assembly.

Abstract: An improved process for gas-phase bleaching of cellulose pulp at high pulp consistency including in series a gas zone space beneath said gas zone for a column of fibrous material, a mixing zone and a dilution zone, wherein a hub body is located centrally at the bottom of the tower and provided with driving means for rotation of the shaft bearing the hub body, and the torque required for rotating the hub body is continuously measured. The rate of dilution liquid is varied inversely with variation in torque thereby maintaining substantially constant the consistency of the diluted fibrous material as withdrawn from the bottom of the tower. The height of the pulp column is measured and kept constant by controlling the withdrawal of diluted fibrous material.

Abstract: A method and apparatus for filling a treatment vessel with a fiber material -- liquid mixture. A conventional feeder rotor, having a number of pockets extending therethrough, has each pocket thereof sequentially filled with chips-liquid mixture in a first position from a pretreatment vessel. A portion of the liquid is withdrawn from the pocket, and the pocket rotates to a second position wherein the chips-liquid mixture in the pocket is discharged into a digester by a liquid flow. The pocket then rotates to a third position wherein the liquid in the pocket is discharged by admitting a gas, such as steam, under pressure into the pocket (and the pocket simultaneously filled with gas), and then to a fourth position wherein the gas is allowed to expand and be transported to a pretreatment vessel while the pocket is filled with cooking liquor, and thereby is ready to begin another cycle.

Abstract: An apparatus and method for the displacement impregnation of cellulosic chips material with digesting liquid. Cellulosic chips material and liquid are fed from a source to a high pressure transfer valve whereat the pressure of the chips and liquid is boosted. The chips are fed from the high pressure transfer valve through a feed system to the topmost portion of a vertical treatment vessel, the vessel having a topmost portion and an impregnation zone in an upper portion thereof below the topmost portion. A countercurrent flow of digesting liquid in the vessel impregnation zone is established to impregnate the chips material with digesting liquid, and displace the water and minerals therefrom, and liquid withdrawn from the top of the treatment vessel is withdrawn into the feed system. The withdrawals insure that essentially no free water enters the impregnation zone. A chips plug is established at the vessel top through which all withdrawn liquid must pass.

Abstract: An apparatus and method for impregnating fiber material with treatment liquid before treatment thereof in a high pressure vertical fiber material treatment vessel. Fiber material and treatment liquid under relatively low pressure flow in a first flow system, continuous withdrawal of liquid from the first system taking place. A second flow system of fiber material and treatment liquid, under relatively high pressure (the second flow system including an impregnation portion of the treatment vessel), is provided. Fiber material entrained in liquid in the first system is transferred to the second system, and the pressure thereof boosted, by a pocketed-rotor transfer device.

Abstract: In counter-current treatment of cellulosic fiber material it is known to have strainers for separation of liquid from the fiber material. In this invention strainers are omitted by introducing pretreated sinking fiber material through an inverted funnel into a liquid filled tank passing treatment liquid counter-currently to the fiber material and extract liquid from a liquid room above the surface of the fiber material and above the open lower end of said funnel. The tank may be operated at atmospheric or at higher pressures to suit the conditions.

Abstract: A static discharger includes a vertical casing connected to a pressurized pulping digester for receiving a stream of fibrous material and having a valve isolated scrap collector positioned on its lower end. A discharge neck on which a blow valve is mounted extends from the casing above the scrap collector and is covered with a grid plate having self-cleaning openings. A pipe mounted tangentially on the casing introduces flooding liquid thereto while a similar pipe may be located on the scrap collector. A sealed casing cleanout opening may be provided. No moving parts are involved since discharger agitations result from the flooding media. Heavy foreign body impurities in the stream sink to the scrap collector where they are removed without process interruption. Buoyant objects remain suspended in the liquid. Blow valve plugging is eliminated. For higher fiber consistency, a grid plate wiping agitator may be advantageously installed in the casing.

Abstract: Raw fibrous material is preheated in a preheater in the presence of steam under a pressure greater than atmospheric pressure and then continuously introduced into a disc refiner, without prior defibration, whereby steam is generated in said disc refiner. The generated steam is continuously conducted away from said disc refiner as subsequent fibrous material is continuously being introduced into the disc refiner in order to obtain a pressure in the disc refiner which is greater than atmospheric pressure but less than the pressure in said preheater.

Abstract: A method and apparatus for filling a treatment vessel, such as a digestor, with fiber material and liquid. A chips-liquid mixture from a pretreatment vessel is fed through a conventional feeding valve to a treatment vessel while the chips-liquid mixture is being acted on by other means in the feeding valve. The feeding valve includes a rotor having a number of pockets extending therethrough, and a plurality of inlets and outlets arranged around the periphery of the valve for communication with the pockets thereof. In a first position of the valve chips-liquid mixture is fed into a pocket, and a portion of the liquid is strained off, then the valve rotates to a second position wherein a quantity of the liquid is displaced by gas or steam while the chips are maintained in the pocket, and then the valve rotates to a third position wherein the chips in the pocket are discharged into the treatment vessel.

Abstract: An improvement in continuously feeding slurry material to vertical upflow treatment towers. The improvement comprises providing a plurality of spaced apart inlet or outlet openings in the bottom inlet end of the tower and opening and closing the openings in timed sequence to allow the material to selectively flow into the tower from different spaced locations but continuously at a substantially constant rate.