Abstract: Medium consistency oxygen delignification of pulp is carried out in a series of tubular reaction zones. Rapid delignification is achieved by agitating the pulp by rotating a timing screw in the first reaction zone at a speed in excess of 10 rpm, modifying the flights on the timing screw to increase the amount of agitation, or a combination of the two. Primary oxygenation is carried out in the first reaction zone while subsequent zones provide the retention time needed for the delignification reaction to go to completion. A thick stock pump is used to introduce the pulp into the first reaction zone.

Abstract: A simple mixing apparatus provides especially for the mixing of treatment fluids with suspensions having a consistency of about 2-15%. First and second cylindrical coaxial housing parts are provided, the second part having a larger diameter than the first part. A fluid inlet introduces fluid axially into the first housing part, and a fluid outlet expels treated fluid tangentially from the second housing part. Stirring and mixing is provided by first and second stirring members rotatable about a common axis, the first stirring member having a number of axially extending, radially upstanding ribs cooperating with similar ribs on the interior of the first housing part, and the second stirring member having a number of radially extending, axially upstanding ribs cooperating with like ribs formed in the second housing part. The suspension is fluidized by the stirring members, and the residence time of suspension with the apparatus is between about 0.01 and 2.0 seconds.

Abstract: Process and apparatus for mixing a wood pulp slurry with a chemical at the consistency at which the slurry exits a washer or the subsequent steam mixer, 7 to 15%. The chemicals would include noncondensable or unsaturated gases such as oxygen, ozone, air, chlorine, chlorine dioxide, sulfur dioxide, ammonia, nitrogen, carbon dioxide, hydrogen chloride, nitric oxide or nitrogen peroxide. Highly superheated steam can also be mixed with the pulp.In the process, the pulp slurry would pass through a mixing zone having a swept area in the range of 10,000 to 1,000,000 square meters per metric ton of oven-dry pulp. The preferred range is 25,000 to 150,000 square meters per metric ton of oven-dry pulp and the optimum is considered to be around 65,400 square meters per metric ton of oven-dry pulp.The pulp slurry passes through an annular mixing zone. Specific designs of the various elements of the mixer are disclosed.

Abstract: A wood pulp slurry is treated with oxygen in a mill with little change to the process or structure of the mill. No special pressure tanks are required. The consistency of the pulp need not be altered for the treatment step. It may be treated at the usual process consistency of the pulp; e.g., it may be treated at the usual consistency of the pulp leaving a washer or subsequent steam mixer without additional dewatering or additional dilution.The oxygen is added into a closed section of the system so that it cannot immediately vent to the atmosphere. Alkali should also be present when the oxygen is mixed with the slurry. The mixing should occur near to the point of oxygen addition.The mixing occurs in a relatively small mixer that intensively mixes the slurry and gas. The mixer has a mixing zone with a swept area of 10,000 to 1,000,000 square meters per metric ton of oven-dry pulp.

Abstract: A wood pulp slurry is treated with oxygen in a mill with little change to the process or structure of the mill. No special pressure tanks are required. The consistency of the pulp need not be altered for the treatment step. It may be treated at the usual process consistency of the pulp; e.g., it may be treated at the usual consistency of the pulp leaving a washer or the subsequent steam mixer without additional dewatering or additional dilution.The oxygen is added into a closed section of the system so that it cannot immediately vent to the atmosphere. Alkali should also be present when the oxygen is mixed with the slurry. The mixing should occur near to the point of oxygen addition.The oxygen is inserted into the pulp slurry and mixed with the pulp slurry between a pair of washers. The second washer may be a vacuum, pressure or diffusion washer.The mixing occurs in a relatively small mixer that intensively mixes the slurry and gas.

Abstract: Washed wood pulp from a continuous digester is treated with oxygen in the blow line from the digester. Most of the treatment occurs within the mixer. The mixer has a mixing zone with a swept area of 10,000 to 1,000,000 square meters per metric ton of oven-dry pulp. A preferred range is 25,000 to 150,000 square meters per ton of oven-dry pulp and an optimum range is around 65,400 square meters per metric ton of oven-dry pulp. Following mixing, the pulp may be taken to a subsequent process, a diffusion washer, or to a storage tank.

Abstract: A wood pump slurry is treated with oxygen in a mill with little change to the process or structure of the mill. No special pressure tanks are required. The consistency of the pulp need not be altered for the treatment step. It may be treated at the usual process consistency of the pulp; e.g., it may be treated at the usual consistency of the pulp leaving a washer or subsequent steam mixer without additional dewatering or additional dilution.The oxygen is added into a closed section of the system so that it cannot immediately vent to the atmosphere. Alkali should also be present when the oxygen is mixed with the slurry. The mixing should occur near to the point of oxygen addition.The oxygen is inserted into the pulp slurry and mixed with the pulp slurry between a washer and the subsequent storage tank.The mixing occurs in a relatively small mixter that intensively mixes the slurry and gas. The mixer has a mixing zone with a swept area of 10,000 to 1,000,000 square meters per metric ton of oven-dry pulp.

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 blade conveyer for a digester of the Bauer M and D type, adapted particularly for treating of wood chips and similar material in the manufacture of cellulose, which is provided with blades with openings enabling passage of the boiling liquid substantially uniformly through the whole space between adjacent blades, securing thus a uniform treatment of the treated material and an efficient performance at different conditions of filling and thus an easy adjustment to conditions of other elements of a manufacturing line.

Abstract: Apparatus for the displacement washing of cellulose fibers suspended in a liquid, as produced by cooking wood pulp in a digester vessel 1. As the fiber suspension settles to the bottom of the vessel it passes through a plurality of axially spaced washing zones 6, whereat water is forced through the suspension in a radial direction from central inlet conduits 16, 16a, 16b to peripheral outlet chambers 9, or vice versa. Such flow displaces the suspension or cooking liquid, and the washed fibers are withdrawn through a bottom outlet 5. The washing liquid is sequentially recirculated through the zones 6 for economy, and the buildup of fibers on the recirculating conduits 19a, 21a, 24a in the vessel is prevented by perforated water discharge pipes 26 disposed just above the conduits.

Abstract: A mixture of wood chips and impregnation liquor is continuously passed through an impregnation zone, the mixture is agitated throughout said impregnation zone to maintain the consistency of the mixture constant and the residence time of the chips uniform throughout said impregnation zone, the mixture is withdrawn from said impregnation zone, excess liquor is removed from the chips and said chips are then digested in a cooking zone.

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: Apparatus for the production of a lignocellulose material from chips, sawdust, chopped plants, bark, small fibres comprising a vertical column with a series of successively-mounted horizontal perforated plates partly abutting upon the inner surface of the column; at the free ends of said plates retaining baffles are secured for partial entrapment of coarse particles of the product; a clearance is provided between the baffle and inner surface of the column and the plates are disposed relative to each other so that baffles of each successive plate are located diametrically opposite to the baffles of each preceding plate thus forming a zigzag labyrinth along the total height of the column for increasing the time of contact of coarse particles of the raw materials with the oxygen-containing gas and alkaline reagent.A pulsator means is operably connected to the column for setting liquid reagents in the column into reciprocating vertical motion.

Abstract: A method and apparatus for treating finely divided fibrous pulp with gas without overpressure in a continuous process. The bulk material is substantially continuously supplied to a reactor having one or more supporting floors having apertures of a shape and size which allow the finely divided material to form bridges across the apertures, said apertures also permitting a continuous flow of gas through the bulk material. The bulk material proceeds through the reactor as a consequence of the bridges being broken by breaking arms sweeping along the upper surface of the supporting floors.

Abstract: Method and apparatus for the continuous distribution and mixing of high concentration pulp with at least one treatment fluid such as chlorine or chlorine dioxide. An enclosed housing has a cylindrical portion, a closed conical wall portion extending inwardly from one end of the cylindrical portion, and a generally converging open conical portion extending outwardly from the other end of the cylindrical portion. High concentration pulp is introduced into the cylindrical portion of the housing, and a rapid circular movement is imparted thereto by rapidly rotating rotor transport blades, so that the pulp is essentially fluidized. Treatment fluid is added to the pulp through the cylindrical housing portion to generally form a layer over pulp rotating in the cylindrical housing portion.

Abstract: Cellulose fibers are treated by providing the fibers in a 10-90% concentration in liquid, and applying elastic pressure shocks to the fibers for a duration not exceeding one second and of a magnitude causing the pressure in the interior of the fibers to exceed 0.2 atmospheres excess pressure. Thereafter the fibers are permitted to expand. The pressure shocks cause liquid to be expelled from the fibers without permanent deformation of the fibers occurring. When the fibers expand, liquid is adsorbed. These steps are repeated until the fibers are completely impregnated with liquid. This prevents the formation of fiber knots when the fibers are substantially dried before being formed into paper. The elastic pressure shocks can be applied by a rotating paddle wheel which intermittently elastically compresses the fibers against an elastic surface of a container.

Abstract: A device for the counterflow treatment of fibrous deformable particles with liquid in stages in a tower. In the tower the particles and liquid flow downward by small movements and the liquid flows upwardly. Each of these successive two movements constitute one stage. The ascent of liquid alone, or filtration in each stage, is produced by introductions of water with adequate pressure through the bottom of the tower. The descent of the mass of particles and liquid or mass movement in each stage, is produced by rapid removal of mass from the lower part of the tower. During filtration periods, the particles suffer only small relative displacements among them, because the upper layer of the particles is retained by a screen, that only permits the flow of liquors; in addition, successive grids extending from the proximity of the screen to the proximity of the bottom of the tower, offer resistance to movement of the particles.

Abstract: Apparatus and method for digestion of cellulose material in a continuous digestion process, that do not require screens in the outlet of the digesting zone. Cellulose chips and digesting liquid at relatively low temperature are introduced into a relatively long and thin cylindrical impregnation vessel, having a first diameter. The chips from the impregnation vessel pass into a digestion vessel having a second diameter substantially greater than the first diameter, the outlet for the impregnation zone into the digestion vessel being disposed well into the digestion vessel and below an outlet(s) disposed in the top of the digestion vessel, and form a chips column in the digestion vessel.

Abstract: A process for bleaching pulp in tank comprises several steps. A pulp slurry and an oxidizing agent are supplied to a first tank compartment. The mixture of pulp slurry and oxidizing agent is agitated at a first power level that corresponds to an approximate minimum power level for a maximum reaction rate on a plot of reaction rate versus power level for a first residence time. The mixture is re-agitated in another tank compartment at a second power level that corresponds to an approximate minimum power level for a maximum reaction rate on a plot of reaction rate versus power level for a second residence time. The second power level is lower than said first power level and corresponds to the amount of unreacted oxidizing agent and unreacted pulp slurry.