Abstract: The present invention relates to a digester and a method for continuously cooking kraft pulp in a single-vessel system (1), preferably a single-vessel hydraulic digester, with chips (2) being fed in at a first end (3) of the digester (1), white liquor (4) being added at at least one position at or near the said first end (3), the chips being impregnated in a cocurrent impregnation zone (5), the chips being cooked in a cooking zone (6) downstream of the impregnation zone, hot black liquor (7) being extracted from at least one extraction strainer section (8), and cooked pulp being discharged (9) at the other end of the digester, and hot black liquor (7) being added (11), (12) to the said impregnation zone (5), and the extract (13) from the first strainer section (14), which is arranged downstream of the position of addition (11a) of the said hot black liquor (7), being largely removed from the digester.

Abstract: A method and apparatus for bleaching high consistency pulp with a gaseous bleaching reagent. The pulp is shredded and then fluffed in the presence of a contacting gas which includes the gaseous bleaching reagent within an upstream vessel comprising a pin/foil contactor so as to suspend the pulp in the contacting gas and react the bleaching reagent with the pulp. The pulp is retained in the contactor for a predetermined time which is sufficient to consume about 75% to about 90% of a selected dose of the gaseous bleaching reagent which is required to delignify the high consistency pulp from an initial Kappa number to an intermediate Kappa number. The pulp and contacting gas are then separately supplied to a porous bed reactor where the reaction of the selected dose of the gaseous bleaching reagent with the pulp is substantially completed so as to further delignify the high is consistency pulp from the intermediate Kappa number to a final Kappa number.

Abstract: The invention refers to a device for mixing chemicals into a pulp suspension, where a high-speed rotor (5) with an open center is mounted inside a mixing chamber (2). It is mainly characterized by at least one further high-speed rotor (5') with open center being provided, the areas covered by these rotors (5, 5') overlapping and the spacing between the axis of the rotors (5, 5') being selected so that the rotor arms (8, 8') extend almost to the center of at least one other rotor (5, 5').

Abstract: An apparatus for delignifying and bleaching a lignocellulosic pulp without the use of elemental chlorine. The bleaching reactor is a horizontal vessel having a central rotatable shaft which preferably contains paddles, cut and folded screw flights or a ribbon flight, to disperse and advance the pulp particles in a plug flow manner while contacting and mixing the pulp particles with a gaseous bleaching agent such as ozone for substantially uniform bleaching thereof.

Abstract: A mixer, having a unique rotor, is particularly suitable for mixing paper pulp having a consistency of about 6-15% (medium consistency) with a bleaching gas having an ozone content of at least one percent, and typically at least six percent. The rotor comprises a disc shaped base, a hub at the center of the base for connecting it to a drive mechanism for driving the rotor at an angular velocity of 1000-6000 rpm, and one or more rings concentric with the base and extending outwardly from the base at least about three inches (and of the same for different heights). A number of blades may extend radially through the center of the base along the contour of the rings, extending outwardly from the base, rings, and hub. Degassing holes may be formed in the hub and connected up to a suitable degassing structure in the mixer. The rings may have a cross-sectional shape corresponding to that of a truncated right circular cone frustum, or may have a rectangular cross-section.

Abstract: The reactor comprises a pressurized vessel having an outlet member at its top and further including a blow line. The outlet member includes a housing that is in fluid communication with the vessel and to which the blow line is connected. A rotor is arranged in the housing for urging pulp in a direction of an inner side of the housing so that the pulp is discharged to the blow line while gas accumulates in the center of the housing. An outlet line is in fluid communication with an outlet channel for removing the gas from the center of the housing.

Abstract: Mixing devices for mixing a processing agent with a pulp suspension are disclosed including a mixing vessel, an agitator mounted on the surface of the mixing vessel to create a flow of the pulp suspension across the mixing vessel, a processing agent supply for supplying processing agent to the flow of pulp suspension, and a flow divider mounted on the inner surface of the mixing vessel opposite the agitator, in which the flow divider includes a substantially vertical front distribution edge and a pair of arcuate front surfaces extending from that edge to the inner surface of the mixing vessel on opposite sides thereof.

Abstract: The present invention relates to a scraper device, preferably a bottom scraper arranged at the bottom of a continuous digester for pulp production, which scraper comprises at least one scraper arm (12), preferably arranged with shovel members (13), a shaft (6) and drive device (15) for driving the scraper arm (12), an axially extending bore (8) inside the shaft (6) for supplying liquid, and a sealing arrangement (3, 4, 5, 14) for sealing between the atmosphere and the medium in which the scraper arm (12) is intended to rotate, the bore (8) extending along only a limited part of the shaft (6) at that end of the shaft (6) on which the scraper arm (12) is arranged.

Abstract: A process and device for mixing fluid into a pulp suspension of cellulose-containing fiber material, in which the pulp suspension is pumped in through a pump inlet, brought into rotation and, at the desired reaction pressure, mixed with the said fluid while passing through a reaction sector comprising a stator shell, a rotor which is coaxial therewith, and at least one fluid inlet, after which the pulp mixture leaves the reaction sector through a pulp outlet, in which the fluid, via the said fluid inlet, is supplied in the vicinity of the center of rotation of the rotating pulp suspension, where the local pressure in the pulp suspension is lower, due to the centrifugal force increasing radially outwards, then the reaction pressure prevailing at the periphery of the pulp suspension.

Abstract: The present invention relates to a process for continuous cooking of chemical pulp, in which the chips are fed into a chip chute (3), which is arranged on top of a high pressure feeder (4) for passing the chips into a downstream, pressurized continuous digester housing comprising a vertical, elongate digester (5) into which the chips are fed at the top and from which the cooked pulp is fed out at the bottom, in order thereafter to be defibred and washed, after which the defibred pulp is screened, and an accepted flow of pulp is obtained which is fed onwards for continued treatment, and a reject flow is obtained which consists principally of knots, which reject flow is thus separatedoff from the pulp flow, the reject flow, which consists principally of knots, being returned to the chip chute (3), preferably after concentration and washing.

Abstract: The present invention relates to a method for continuous cooking of kraft pulp in a single-vessel system (1), preferably a single-vessel hydraulic digester, with chips being conveyed from a high-pressure feeder (2) in a transfer line (2A, 4A) to a first end (3) of the digester (1), the chips being impregnated, in a liquid containing black liquor, in a concurrent impregnation zone (5), the chips being cooked in a cooking zone (6) subsequent to the impregnation zone, hot black liquor (7) being extracted from at least one extraction screen section (8), and cooked pulp being discharged (9) at the other end of the digester. The chips are, when they leave the high-pressure feeder (2), included in a first liquid, which first liquid is in the main separated from the chips in a liquid exchanger (4) installed in the transfer line (2A, 4A) and is replaced by a second liquid which contains black liquor.

Abstract: A guide vane is provided in a pin fluffer to assist in pulp mat retention during fluffing by providing a cyclic lift component to the mat as it passes over the vane thereby also further increasing retention time obtained in the fluffer.

Abstract: An oxygen delignification method and apparatus in which a charge of heated wood pulp is reacted with oxygen in the presence of a charge of caustic soda in a plurality of reaction stages located between mixing stages in which caustic is mixed with the wood pulp. The use of the plurality of mixing stages reduces peak pH exposure of the wood pulp that would otherwise occur if the charges of caustic and wood pulp were mixed all at once. Moreover, the caustic mixed in such manner replenishes neutralized caustic and ensures that the average pH level is increased above that in conventional oxygen delignification. The increase in average pH level favors an increase in the delignification. Filtrate from a washing stage is introduced into the mixing stages to prevent wood pulp degradation.

Abstract: The flow patterns of the wood/paper pulp in a paper pulp treatment tower are controlled to provide for even flow through and discharge of the pulp from the upper end of the tower. Flow-altering fluids are injected into the pulp stock in the tower via appropriately positioned nozzles which create flow-altering fluid streams in the pulp stock. The streams are operable to produce either an inwardly directed pulp flow, or an outwardly directed pulp flow, whichever is desired. The system results in smooth, relatively even movement of the pulp stock from the bottom of the tower to the top, so that each fraction of the pulp mass will spend substantially the same dwell time in the tower, whereby the pulp mass is evenly processed and reacted in the tower. The resultant treated stock is superior to pulp stock treated in a tower without such flow controls.

Abstract: A varying tapered conical shell is provided with a varying taper conical rotor having pinlike radially extending projections whereby the varying taper assures more uniform solids distribution in a fluffing solids/gas contactor.

Abstract: An improved method of processing baled waste material containing waste paper having fibers contaminated to various degrees for recovering usable cellulosic fiber pulp from the bale in which the bale contents are impregnated with a fiber swelling and debonding fluid by enclosing the bale within a closed chamber and subjecting the chamber and contained bale to multiple pressure environmental conditions, that preferably includes a vacuum, while submerging the bale in the debonding fluid. The impregnated bale contents are allowed to soak for a sufficient period that the lesser degree contaminated fibers become swollen after which the bale is subjected to a sufficiently low degree of pulping agitation as initiates separation of the swollen fibers without significant damage to the fibers and which does not significantly decrease the sheet size of higher degree contaminated bonded fibers and other contaminants.

Abstract: A pulp digester having a number of screening/cleaning units mounted within the digester. Each unit has a screen member and a cleaning propeller which is mounted adjacent the inner surface of the screen member. There is for each unit a hydraulic motor which is positioned entirely within the digester housing, and which rotates the propeller. Hydraulic lines extends through sealed openings in the digester wall and power is supplied from an exterior hydraulic pump which is controlled by a valve.

Abstract: An apparatus and method for bleaching high consistency lignocellulosic pulp using ozone supplied in an ozone containing gas. The bleaching reactor apparatus according to the invention is a generally cylindrical vessel itself being rotatable or with a rotatable shaft having radially extending paddles arranged in a configuration to minimize axial dispersion of the pulp and maximize radial dispersion of the pulp to provide a radially dispersed plug flow of pulp through the reactor in the presence of the ozone to provide substantially uniformly bleached pulp.

Abstract: A method and apparatus for reclaiming cellulosic fibers from a bale containing waste papers, in which the bale is positioned in a treatment enclosure, and the enclosure is placed under a vacuum. A treating fluid is drawn into the enclosure, which penetrates the bale interior spaces, and produces a preferential swelling-of uncontaminated cellulosic fibers. After the treating fluid is withdrawn from the enclosure, a slurrying fluid is passed through the bale contents, to form a fiber-fluid suspension slurry.

Abstract: An apparatus and method for bleaching high consistency lignocellulosic pulp using ozone supplied in an ozone containing gas. The bleaching reactor apparatus according to the invention is a generally cylindrical vessel with a rotatable shaft having radially extending paddles arranged in a configuration to minimize axial dispersion of the pulp and maximize radial dispersion of the pulp to provide a radially dispersed plug flow of pulp through the reactor in the presence of the ozone to provide substantially uniformly bleached pulp.

Abstract: A two stage ozone-pulp bleaching method and apparatus are disclosed. In the first stage, high consistency pulp particles are turbulently mixed and contacted with a gaseous mixture containing ozone to mix and contact substantially all of the pulp particles with ozone to react at least a portion of the pulp particles with the ozone. Pulp particles and gaseous bleaching mixture are then directed to a second stage including a quiescent pulp bed. Pulp particles may complete their reaction in the bed, which also serves to strip ozone which was not contacted with pulp particles in the first stage from the gaseous bleaching mixture.

Abstract: A substance kneader, specifically for cellulose fiber suspensions, with kneading elements arranged at the periphery of a rotor encased in a housing. Two drum type rotor parts and a rotor part disposed in between feature a feed worm conveyor for each rotor part. In the area between facing ends of the worm conveyors, and symmetric to this area, are the inlet openings of the housing. On the ends away from each other, of the rotor parts, are the outlet openings of the housing. The outlet openings are each coordinated with delivery worm conveyors having variable-RPM drive for control of throughput and/or dwell time of the substance to be kneaded.

Abstract: Laboratory equipment for practicing experiments and mixing ozone with medium consistency cellulosic pulp allows precise control of the timing and amount of ozone injected into the mixer, providing a method of testing that is more accurate than prior methods. An injection cylinder and fluidizing laboratory mixer are utilized. Pulp is fed into the mixer, the cylinder is charged with a known predetermined amount of ozone containing gas, the ozone containing gas is injected from the cylinder into the mixer, the mixer is operated to effect mixing of the ozone containing gas with the pulp for a predetermined period of time, and then gas containing residual ozone (which has not reacted with the pulp) from the mixer is vented from the mixer, including by utilizing a purge gas such as nitrogen. The ozone is created by an ozone generator which continuously operates. A three-way valve directs the output of the ozone generator to an ozone destruction device when the ozone is not being charged into the cylinder.

Abstract: Medium consistency (e.g. about 5-18%) paper pulp is mixed with a treatment fluid by fluidizing them while subjecting them to a constantly changing shear field in radial and axial planes. This is accomplished by providing a mixer rotor having a constantly varying cross-section along a dimension of elongation. The rotor may comprise a body having an external surface simulating alternately oriented cone frustums along its axis of rotation, with vanes connected to the external surface and including portions following the surface contour. A disk may or may not be provided at the end of the body connected to a shaft. A first interior housing portion has a configuration mimicking that of the rotor, while a second housing portion defines a fluidization zone with the disk.

Abstract: An apparatus provide for the production of low kappa number (e.g. below 20) kraft paper pulp, and a low viscosity black liquor which is easily transported to a recovery or disposal stage. Comminuted cellulosic fibrous material is steamed, passed to a treatment vessel, land then introduced into the top of a continuous digester. Black liquor is withdrawn from the digester and heated about 20-40 degrees C above cooking temperature (e.g. about 170 degrees C), and then introduced into contact with the material in the treatment vessel. After the material is treated with the black liquor, it is withdrawn from the treatment vessel, and passed to the recovery or disposal stage. White liquor may be introduced into the treatment vessel after black liquor withdrawal, after passing in heat exchange relationship with liquid recirculated from an impregnation vessel to a high pressure feeder.

Abstract: An apparatus for treating and discharging a medium, such as cellulosic fibrous material, in a container or bleaching tower includes an agitating and treating arm coupled to a rotating discharge pipe. A treatment medium or a diluting liquid is dispensed through orifices in the agitating and treating arm disposed in the bottom of the container. The cellulosic fibrous material suspension is discharged from the bleaching tower. The treatment medium or the diluting liquid is fed through the orifices in the agitating and treatment arms as a function of the state variables of the treatment medium and/or the medium to be discharged. The orifices include an obturator to open and close the orifices as a function of the pressure differential between the treatment medium and the medium to be discharged in the area of obturators during the discharge operation.

Abstract: Medium consistency (e.g. about 5-18%) paper pulp is mixed with a treatment fluid by fluidizing them while subjecting them to a constantly changing shear field in radial and axial planes. This is accomplished by providing a mixer rotor having a constantly varying cross-section along a dimension of elongation. The rotor may comprise a body having an external surface simulating alternately oriented cone frustums along its axis of rotation, with vanes connected to the external surface and including portions following the surface contour. A disk may or may not be provided at the end of the body connected to a shaft. A first interior housing portion has a configuration mimicking that of the rotor, while a second housing portion defines a fluidization zone with the disk.

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

Abstract: A method of digesting lignocellulose materials impregnated with solutions of hydroxides or salts of alkali or alkaline earth metals, the ratio by weight of the solution retained during the impregnation and the dry matter being less than 2, in a digester, characterized by subjecting the impregnated materials before the digestion to a treatment with live steam under a pressure equal to or greater than that present in the digester so that a part of the steam, by giving off its sensible heat to the impregnated material and condensing, assures the preheating and penetration of the impregnation liquor up to the center of the material. The time of digestion is shorter and the pulp obtained more homogeneous.

Abstract: An apparatus for delignifying and bleaching a lignocellulosic pulp without the use of elemental chlorine. The bleaching reactor is a horizontal vessel having a central rotatable shaft which preferably contains paddles, cut and folded screw flights or a ribbon flight, to disperse and advance the pulp particles in a plug flow manner while contacting and mixing the pulp particles with a gaseous bleaching agent such as ozone for substantially uniform bleaching thereof.

Abstract: Organic constituents in a liquid, such as a waste water from a municipal or industrial process (e.g. bleach plant extraction liquor from the bleaching of paper pulp) may proceed effectively without the addition of alkali. When the organic constituents are reacted with an oxygen containing gas at appropriate pressure and temperature conditions, oxidized organics and gaseous acidic products of oxidation (e.g. CO.sub.2) that are produced are continuously and immediately removed from the liquid so that they do not significantly contribute to lowering of the pH of the liquid, so that the reaction may proceed and the liquid remain alkaline.

Abstract: In a method of producing high-yield pulp from pulp chip material containing lignocellulose the material is treated with steam in a steam treating station (1) for driving air out of the material and heating the latter. Heat treated material is mixed in a mixing station (8) with a liquid containing chemicals. The mixture of steam treated material and said liquid is transferred from the mixing station to an impregnation station (25) for impregnating the material by means of said chemicals. Impregnated material is supplied to a refining station (36) for refining the material. According to the invention the steam treated material is mixed with said liquid in proportions, such that the created mixture of material and liquid leaving the mixing station (8) assumes a flowing pumpable consistency. Further, said flowing mixture is pumped from the mixing station (8) to the impregnation station (25).

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 static distributor is provided with a top surface that slopes upwardly from the center port opening through which chlorine dioxide and pulp stock are pumped into a bleaching tower. The upwardly sloping sides of the distributor provide a dish-shaped or concave configuration influencing the flow from the center port opening upwardly and outwardly toward the circumference of the tower. The static distributor is provided with side openings formed by vertical support plates. The vertical support plates are spaced about the circumferences of the concave or dish-shaped flow surface to support the same on a base and change the flow distribution so that a good portion of the flow is radial between the plates rather than vertical. The radial flow is mixed with the flow undergoing upward influence provided by the dish-shaped center portion of the distributor, which causes more complete mixing and the formation of a vortex-type flow in the bleaching tower.

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: Wood chips, or like comminuted cellulosic fibrous material, are treated in a vertical presteaming vessel in the production of paper pulp. The vessel does not employ a vibrating discharge structure as is conventional, but rather utilizes as a discharge structure a plurality of rotating arms having depending blades, mounted at the bottom of the vessel, which force the wood chips toward a discharge opening in the vessel bottom. The steam is introduced into the vessel through a vertical tube concentric with the vessel, and surrounding a rotatable shaft which is connected to the arms of the discharge device. A truncated cone is provided at the bottom of the steam tube, making a slip connection with the tube, and overlies the discharge opening. The cone has maximum horizontal dimensions greater than those of the outlet, to cause the chips to move radially outwardly into contact with the discharge element.

Abstract: For bleaching cellulose pulp or a fraction thereof, e.g. reject pulp, the cellulose pulp or fraction, having a concentration of 0.5-10%, preferably 3-6%, is introduced into a screw press comprising at least a first (47) and a second (48) dewatering zone, is dewatered in the first zone to a concentration of 20-40%, whereupon a liquor of bleach chemicals is introduced centrally into the pulp which, during continued treatment, is dewatered in the second zone to a discharge pulp concentration of 15-50, preferably 15-30%, the liquid pressed out of the second zone, together with fresh bleach chemicals, being returned to the pulp in the screw press as liquor of bleach chemicals.

Abstract: A method and apparatus for continuous fiber material treatment of a fiber column without compaction of the column. A liquid layer is disposed between upper and lower treatment zones (i.e. between a cook and wash zone), and apparatus is provided for interrupting the fiber column of the upper zone. The apparatus may include a conical table which generally supports the fiber column of the upper zone yet allows passage of fiber material from the upper zone to the lower zone to allow formation of another fiber column in the lower zone. The liquid layer area may be of the same or smaller cross-sectional area than the upper zone, and the lower zone may be horizontally offset from the upper zone if desired.

Abstract: A system is provided to produce sugars from a liquid-solid mixture containing biomass, and an acid, wherein the mixture is heated to an appropriate temperature to achieve hydrolysis. The liquid-solid mixture is introduced as a stream into the circular-cylindrical chamber of a cyclone reaction vessel and steam is introduced to the vessel to provide the necessary heat for hydrolysis as well as to establish the liquid-solid mixture in a rotary flow field whereby the liquids and solids of the mixture move along spiral paths within the chamber. The liquid-solid mixture may be introduced at the periphery of the chamber to spiral down toward and be discharged at or near the center of the chamber. Because of differing mass, the solid particles in the mixture move radially inward at a different rate than the liquid and that rate is controlled to maximize the hydrolysis of the solids and to minimize the decomposition of sugars, thus formed.

Abstract: Washing machine for washing off or separating plastic film, for example polythene, from paper or cellulose fibers or other pollutants comprising a container 1 into which the material to be washed consisting of plastic film with residual quantities of paper or cellulose or other pollutants is introduced at the same time with the water or subsequently thereto and then stirred by washing mechanical means, wherein said container 1 has a concentric surface 3 inside it which is provided with holes and forms an annular chamber 4 and wherein one or two vertical rotary shafts 5 and 6 are provided rotating in opposite directions with respect to each other and respectively bearing two series of radial agitators 7 and 8 penetrating into each other in the center of the container so that the water containing paper or cellulose fibers or other pollutants passes through the holes being thus discharged separately from the plastic film and wherein each of said series of agitators 7 and 8 carries one or more agitators provided

Abstract: A bleach system for blending gaseous chlorine with a paper pulp slurry flow stream by mixing the chlorine with a larger quantity of steam prior to blending the chlorine/steam gas mixture with bleach washer filtrate which serves as carrier water for a multiplied number of gas bubbles entrained in the filtrate. As the cooler filtrate water extracts heat from the mixed gas bubble, the steam constituent condenses to collapse each bubble to a fraction of the original volume thereby providing a larger number of smaller chlorine bubbles than otherwise available from conventional phase mixing injectors.The mixed phase flow stream of chlorine and filtrate is thereafter blended with the pulp slurry flow stream by shear induced turbulence resulting from a greater injection velocity of the mixed phase stream into the center of the slower moving slurry stream.

Abstract: The present invention provides a reactor adapted to simultaneously accomplish chemical reactions and operations of size reduction of the solid materials in suspension and particularly for treatment in the cellulose and/or paper pulp industry. The reactor provides an essentially closed working environment and is provided in the lower part with a rotor which creates turbulence with flows over essentially the whole volume of the closed environment and is adapted to realize said conditions of the size reduction of solid materials with intimate mixing of same with the suspending liquid.

Abstract: An apparatus used in the pretreatment of wood chips in a process for converting biomass to a liquid hydrocarbonaceous fuel. The apparatus functions to break down the wood chips to a size distribution that can be readily handled in a slurry form. Low maintenance operation is obtained by hydrolyzing the chips in a pressure vessel having no moving parts.

Abstract: A process and apparatus for the acid hydrolysis of waste cellulose to glucose of the type wherein waste cellulose is continuously fed into an inlet port of a twin screw extruder, water is continuously fed into reaction zone in the extruder, downstream of the inlet port, the cellulose is continuously reacted with water in the presence of an acid catalyst at elevated temperature and pressure in the reaction zone while being continuously conveyed to an outlet port of the extruder having a given diameter and the reacted cellulose is discharged from the extruder while the elevated temperature and pressure in the reaction zone is maintained. The elevated pressure is maintained by forming a dynamic seal zone at the upstream end of the reaction and continuously discharging the reacted material downstream of the outlet port at a predetermined volume rate of flow to maintain the pressure by passing the discharge through an orifice pipe having a smaller diameter than the given diameter of the outlet port.

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 dispersion apparatus for the preparation of waste paper comprises fittings arranged within a housing and composed of a rotor containing ring-shaped concentric rows of teeth and a stator containing ring-shaped concentric rows of teeth. For the removal of the dispersed substance or material an additional rotor ring containing a number of transport teeth is mounted upon the rotor and an additional stator ring is mounted upon the stator. The stator ring possesses an opening above the discharge chute or portion of the apparatus which extends through an angle of about 90.degree.. The apparatus composed of the rotor ring and the transport teeth and the stator ring containing the opening renders possible removal of the dispersed substance or material, without altering its consistency and without there occurring cooling of the processed substance or material.

Abstract: Good temperature and pH control as well as uniform mixing of pulp or other fibrous materials is achieved in a medium consistency oxygen delignification method and system. Alkaline chemicals are sprayed, optionally using oxygen gas as the atomizing agent, into the gas space above the level of pulp maintained in one or more substantially horizontal tubular reaction vessels. At least a part of the steam requirement of the reaction is added only after the major portion of alkaline chemicals has been added to the system. In other embodiments of the invention, alkaline chemicals may be injected into the substantially vertical conduit connecting two reaction vessels or two different alkaline chemicals may be injected at different points in the system.

Abstract: A method and apparatus provide 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: An apparatus and process for the oxygen delignification of pulp is provided in which the pulp is transported by means of timing screws in essentially plug flow through one or more substantially horizontal reactor tubes. Oxygen gas is injected into the system at a point adjacent to the pulp inlet and travels concurrently in substantially plug flow with the pulp through the system. In this manner, the pulp is initially exposed to gas of a high oxygen partial pressure while gas vented from the system adjacent the pulp outlet is of low oxygen partial pressure and has a high content of diluent gases. The process and apparatus avoid the formation of gas pockets and hot spots which may adversely affect the pulp. In an alternate embodiment, a countercurrent gas flow process is disclosed. Also provided is a catalytic treatment and recirculation system for the vented gas which permits efficient use of oxygen within the system.

Abstract: A continuous digester discharges pulp without mechanically engaging the pulp, by using one or more discharge transitions with one dimensional convergence and side relief. The transitions may be mounted within a pre-existing digester shell (after removal of the discharge rotor), and supported by a number of braces and/or a skirt shaped like a truncated cone. The operation of a digester, or other continuous vessel, may be controlled by automatically sensing the level of comminuted cellulosic fibrous material in the vessel and automatically controlling the introduction of dilution liquid into the vessel to discharge the material from the vessel in response to the sensing.