Abstract: An improved hood enclosure for isolating wood pulp washing equipment from the ambient environment. The hood has a pair of end members, a pair of skirts along each side to connect to the end member together, and an upper spine also connected at each end to the end members. A pair of clamshell style doors are mounted to the spine along longitudinal hinge lines and are opened vertically. A plurality of access doors are positioned within the skirts, and a plurality of spray or shower pipes penetrate the hood through an end panel to deliver wash liquid to the internal wash drums positioned within the wash vat. Several sealing methods are incorporated to provide sealable access for the access doors, the clamshell doors, and access to the interior of the washing vat for the shower pipes. The clamshell doors abut a peripheral neoprene sealing gasket and are held against the gasket by their own weight.

Abstract: A method of manufacturing high purity fiber cement grades of cellulose fibers is described. Additional washing steps, coupled with an elevated temperature, are used in the process to extensively wash the pulps and remove substantially all COD components remaining in the pulps. The pulps are counter-currently washed by diffusion and dewatering at elevated temperatures following the brown stock washer systems. During the additional washing steps, the pulps are soaked in counter-current heated water for a pre-determined time and some chemicals may be introduced to chemically break down the COD components in the pulps and to make them more soluble in the aqueous solution. The additional washing steps can be performed using existing equipment at conventional pulp mills. A formulation and a process of making fiber reinforced cement composite materials are also described using the low COD and high purity cellulose fibers.

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: A method of treating solid containing material derived from effluent or sludge from a plant for de-inking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: A multi-function process is described for the separation of cellulose fibers from the other constituents of lignocellulosic biomass such as found in trees, grasses, agricultural waste, and waste paper with application in the preparation of feedstocks for use in the manufacture of paper, plastics, ethanol, and other chemicals. This process minimizes waste disposal problems since it uses only steam, water, and oxygen at elevated temperature in the range of 180° C. to 240° C. for 1 to 10 minutes plus a small amount of chemical reagents to maintain pH in the range 8 to 13. An energy recuperation function is important to the economic viability of the process.

Abstract: Process and device for the flotation of contaminates out of an aqueous fibrous suspension using a foam. The process includes creating the foam, introducing the fibrous suspension into the foam, transferring contaminates from the fibrous suspension to the foam, and removing some portion of the fibrous suspension from the foam as an accepted stock. The device includes a liquid containing area, a mechanism for introducing a gas into the liquid containing area, and a mechanism for introducing the fibrous suspension into a foam containing area arranged to be adjacent the liquid containing area.

Abstract: The invention relates to a process for continuous cooking of wood chips at elevated pressure and temperature in a vertical digester (1) for production of chemically dissolved pulp.

Abstract: The invention relates to a process for continuous cooking of wood chips at elevated pressure and temperature in a vertical digester (1) for production of chemically dissolved pulp.

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 washing system for washing a fiber suspension associated with a fiber stock preparation system, includes a plurality of rolls and a porous fabric carried by the plurality of rolls in a closed loop. The closed loop includes a lower run defining a washing zone, with the porous fabric moving in a running direction through the washing zone. The porous fabric has an upper surface in the washing zone which carries the fiber suspension thereon. A headbox is positioned with the closed loop and above the porous fabric at an upstream end of the washing zone. The headbox discharges a fiber suspension to be washed onto the upper surface of the porous fabric. An accept removal device is positioned within the closed loop and above the porous fabric at a downstream end of the washing zone. A plurality of showers, each having an inlet, are positioned within the closed loop and above the porous fabric in the washing zone between the headbox and accept removal device.

Abstract: A method and an apparatus for washing a fiber pulp mixture, whereby water and, with it, ash and other particle-type impurities are removed from the fiber pulp mixture. The fiber pulp mixture is fed between two wires in a dewatering section so that water and ash are removed from the fiber pulp through both wires, after which the wires and the fiber pulp between them are led to run along a curved surface to remove any extra water by means of the tension of the wires and centrifugal force.

Abstract: A method of making sanitary paper products from coarse fibers. The method includes the steps of: (a) pulping coarse fibers in water with agitation to produce a pulp slurry, the pulp from the coarse fibers having an average fines content of greater than about 40%; (b) using an effective amount of pulp washing to reduce the fines content and increase the Canadian Standard Freeness; (c) introducing the pulp at a papermaking consistency into the headbox of a paper making machine; and (d) utilizing the pulp in a paper making process to produce sanitary paper products.

Abstract: Processes are disclosed for extracting sugar rich liquor from sugar cane. The sugar cane is first treated by pulping it in two tub type pulpers having a rotating impeller. The contents of the first pulper are extracted through the bedplate of the extractor and are forwarded onto the second pulper. The contents of the second pulper are extracted through the bedplate of the extractor and are forwarded to form a mat on a moving belt countercurrent extractor of the type having a foraminous belt. Negative pressure is applied below the belt to assist the extraction of a sugar rich liquid component through the belt. The material passes through several separation zones as it travels on the belt with liquid applied to the mat from a region above the belt. The extracted liquid component is collected for further processing.

Abstract: Chemical cellulose pulp is made from sawdust utilizing a static down-flow retention vessel. By adding steam and cooking liquor to a flow of sawdust a heated slurry, at a cooking temperature of about 250-350° F., is produced. The heated slurry is, at superatmospheric pressure, moved downwardly in the static down-flow retention vessel while cooking temperature is maintained, for a time period of about 0.5-6 (preferably 1 to 3) hours, the slurry having a consistency of about 5-30%. At superatmospheric pressure, without significant reduction in pressure from the retention vessel, the slurry is cooled to well below cooking temperature by diffusing cooling liquid through it, as in a conventional pressure diffuser. The discharge from the retention vessel is preferably substantially solely gravity action (e.g. using a discharge with single convergence and side relief).

Abstract: The invention relates to a method of washing a fiber pulp mixture, in which method the fiber pulp mixture is fed between two filter wires running in the same direction. There is a convergent dewatering space in the direction of travel of the wires, where water is removed from the pulp. According to the idea of the invention, the thickness of the pulp layer being fed between the wires is adjusted during operation, since the ash and fines content of the washed fiber pulp is essentially dependent on the basis weight of the fiber web being washed. In a preferred embodiment of the invention, the height of the slice at the output end of the dewatering space is adjusted. The essential idea of another preferred embodiment of the invention is that the speed of the wires is adjusted. The invention also relates to an arrangement comprising means for adjusting the thickness of the pulp layer being fed between the wires, i.e. the basis weight of the fiber web being washed.

Abstract: The process of the present invention purposefully precipitates a portion of the dissolved lignin onto pulp fibers to improve pulp yield of unbleached pulp. The resulting retention of lignin on the pulp creates an increase in pulp yield. Washing the pulp in a series of washer stages sequentially removes entrained lignin. Between each of the washer stages, adding dilution water repulps a pulp mat that exits from a prior washer stage and creates a pulp stream for a next washer stage. After at least one of the washer stages, adding an acidifying agent to the pulp stream forms a pulp product by precipitating the entrained lignin onto cellulosic fibers contained in the pulp stream. Finally, the process removes the pulp product from the series of washer stages with the pulp product having at least about a 1 unit increase in Kappa number.

Abstract: The problems of non-uniform treatment of paper pulp that may be caused by differential flow velocities within a vessel, channeling, and/or disruption of the pulp flow, are substantially eliminated by providing a non-circular cross-section substantially atmospheric pressure vessel with at least one screen surface, and typically a liquid introducing device. The vessel, screen surface, and liquid introducing device are constructed and positioned with respect to each other so that during the treatment of a pulp slurry the slurry has substantially uniform width in a treatment zone, and there is substantially uniform resistance to the flow of slurry over the screen surface over any particular cross-section of the vessel in the treatment zone, and its consistency varies less than 6% in the treatment zone (e.g. between 8-14%).

Abstract: The process of the present invention purposefully precipitates a portion of the dissolved lignin onto pulp fibers to improve pulp yield of unbleached pulp. The resulting retention of lignin on the pulp creates an increase in pulp yield. Washing the pulp in a series of washer stages sequentially removes entrained lignin. Between each of the washer stages, adding dilution water repulps a pulp mat that exits from a prior washer stage and creates a pulp stream for a next washer stage. After at least one of the washer stages, adding an acidifying agent to the pulp stream forms a pulp product by precipitating the entrained lignin onto cellulosic fibers contained in the pulp stream. Finally, the process removes the pulp product from the series of washer stages with the pulp product having at least about a 1 unit increase in Kappa number.

Abstract: The invention comprises, in one form thereof, a method of removing wax from recycled cellulosic fiber. The cellulosic fiber is pulped in a pulper to a suspension with a consistency of less than about 10% by weight. The suspension is then screened to remove coarse and fine contaminants. The screened suspension is diluted to a consistency of less than about 3% by weight. The wax is removed from the diluted suspension using a froth flotation device. The suspension is then washed and/or thickened.

Abstract: An aqueous slurry containing dissolved solids and a high concentration of suspended solids is positioned as a mat between a pair of porous endless belts to provide a composite structure. The composite structure is moved through a treating zone and subjected to alternate stages of compression and relaxation. In a preferred mode, the compression and relaxation are achieved by passing the composite structure over a series of spaced rolls in a manner such that a first belt of the pair is in direct contact with one of the rolls and a second belt of the pair is in contact with the next adjacent roll. A liquid stream containing a high concentration of dissolved solids is cascaded over the mat in a countercurrent fashion, with the result that dissolved solids of the liquid stream are dissolved in the aqueous phase of the mat when the mat is subject to relaxation. The mat containing the increased concentration of dissolved solids and suspended solids can then be compacted and the solid residue can be landfilled.

Abstract: Disclosed is a process for washing or otherwise treating paper pulp. More specifically, a multi-stage paper pulp washing process including the use of a defoamer/emulsifier mixture which is adjusted at a paper manufacturing site for each stage. The same defoamer may be used in each washing stage. However, solubility is adjusted at the paper manufacturing site by adding a small amount of emulsifier to the defoamer as appropriate for the particular stage.

Abstract: A method of displacement washing of cellulose pulp achieves substantially optimal results without the consumption of excessive clean wash liquid. In the practice of the method there is at least one washing stage, and a second stage, including a suction, press, and/or thickening stage, following the washing stage. Cellulose pulp is fed to the washing stage, and then the washed pulp is fed to the second stage. A first filtrate is withdrawn from the second stage and a second filtrate is withdrawn from a washing stage of the at least one washing stage, or the second stage. The first filtrate is directed to the washing stage and the first filtrate is used as washing liquid in the washing stage. For example the washing stage may include a last washing stage in a multi-stage fractionating washer, and the second stage may be in the fractionating washer; and the first filtrate may be directed to the last washing stage of the multi-stage fractionating washer.

Abstract: The present invention relates to a method for treating a pulp suspension in which the suspension is rotated in a rotationally symmetrical, rapidly rotating and permeable screen basket so that the suspension is subjected to the influence of a centrifugal force and dewatered at the same time as the suspension is conveyed by a rotating screw along the inner wall of the screen basket. The invention is characterized in that the suspension is caused to rotate by means which are arranged at the entrance to the screen basket, and in that the outer edges of the said screw bear against or are immediately adjacent to the screen basket and rotate at a higher speed than does the screen basket so that the screw scrapes the inner wall of the screen basket.

Abstract: The invention realizes an improved mechanical strainer for fibrous suspensions including: a rotor; a filtering basket substantially coaxial externally to said rotor; an interspace defined between the side surfaces of said rotor and of said filtering basket; an outer casing suitable to house said filtering basket and said rotor. Inside this outer casing there are: a feeding chamber receiving the fibrous suspension to be treated, a delivery chamber of the "accepted" and a waste chamber of the "waste". The rotor is provided with a plurality of diffusing ducts developing through diverging ways according to the flow direction and being suitable to pipe the fibrous suspensions to be treated from said feeding chamber to said interspace.

Abstract: Filtrates from bleach plants for cellulosic (paper) pulp non-chlorine bleaching sequences are treated to minimize the consumption of ozone in ozone bleaching stages. Organic material in the filtrate used in a washer just prior to an ozone stage is oxidized to make the organic material less attractive to the ozone. It may be oxidized by indirectly heating the filtrate, and then reacting it with oxygen gas in a reactor. Alkali may be added to the filtrate in the reactor. Metallic ions are also removed from the system by applying an electrical potential either to the filtrate, an entire washer prior to the ozone stage, or to the pulp line prior to the ozone stage. All of the wash filtrates are treated and recirculated so as not to discharge any wash filtrates into the environment, or so that the only wash filtrate discharged from the washing system of the bleaching plant is a small stream used for smelt dissolution. A typical non-chlorine bleaching sequence utilized may be OAZEZP.

Abstract: A process for thickening a fibrous pulp suspension by guiding the suspension between a rigid first face and a flexible second face that move in relation to each other and form a converging draining gap, where the first face and/or the second face is/are water permeable, and where the process includes providing the suspension to be drained, forming from the suspension a fibrous pulp layer with a solid matter content of at least about 4% on at least one of the first face and the second face, guiding the fibrous pulp layer into the draining gap, applying a pressure differential in the draining gap via the second face to thicken the fibrous pulp layer, the pressure differential being formed by stretching the second face and pressing the first face and the second face toward each other to drain water from the fibrous pulp layer, and transporting the thickened fibrous pulp from the draining gap.

Abstract: A method is provided by which it possible to intensify a cellulose pulp wash without requiring the purchase of additional equipment. In a washing system having a plurality of stages with a filtrate from each stage, the stages in sequence being N, N+1, etc., and each stage including filtrates F.sub.N and F.sub.N+1, etc., part of the filtrate F.sub.N (e.g. about 5-30 %) is combined with all or part of the filtrate for F.sub.N+1 to produce a combined filtrate, and the combined filtrate is fed in washing stage N as wash liquid. The part of the filtrate F.sub.N that is taken for use as wash liquid in stage N is typically from the end of the washing stage N. The process may be repeated for most of the stages of the washing system.

Abstract: A method for washing pulp in a multistage pulp washing operation involves controlling operating conditions so as to maximize the efficiency of the operation particularly in response to determination of the percent consistency off the discharge side of each drum washer. The major variables that are useful to control are vat dilution flow, drum speed, vat level set point, drainage aids or defoamers, press roll pressures, vacuum break position, and temperature of the last stage showers.

Abstract: A method of papermaking having zero liquid discharge. A pulp slurry is produced from recycled cellulosic material and the slurry contains suspended cellulosic fiber material, solid contaminants and dissolved water soluble solids. The pulp slurry is subjected to a cleaning operation to produce a first flow stream containing the cellulosic fiber material and dissolved solids and a second flow stream containing dissolved solids along with solid contaminants. The first flow stream is washed with water to remove a substantial portion of the dissolved solids and provide a washed pulp which is used in a papermaking machine to produce a paper sheet. The second flow stream from the cleaning operation is compacted to produce a solid residue that can be landfilled and a liquid residue containing dissolved solids that can be recycled to the pulp cleaning operation.

Abstract: A process for converting components of poultry production feather waste into value-added products involves a single counterflow or batch system wash in a polar organic solvent solution. The feather waste can contain loose, picked feathers, and non-feather avian parts. The feather-waste stream is exposed to a concentration gradient of solvent which sanitizes, denatures, dehydrates, and de-oils it. In one aspect, the counterflow contact between solvent solution and feather waste takes place in an inclined screw conveyor. The process produces avian oil and protein from a liquid intermediate stream and dry fiber and protein powder from the converted waste stream. Fiber from this process can be used in fabrics, composites, extrusions and laminates. Oil and protein can be used in biochemical, pharmaceutical, cosmetic, animal feed, and fertilizer products.

Abstract: An improved hood enclosure for isolating wood pulp washing equipment from the ambient environment. The hood has a pair of end members, a pair of skirts along each side to connect to the end member together, and an upper spine also connected at each end to the end members. A pair of clamshell style doors are mounted to the spine along longitudinal hinge lines and are opened vertically. A plurality of access doors are positioned within the skirts, and a plurality of spray or shower pipes penetrate the hood through an end panel to deliver wash liquid to the internal wash drums positioned within the wash vat. Several sealing methods are incorporated to provide sealable access for the access doors, the clamshell doors, and access to the interior of the washing vat for the shower pipes. The clamshell doors abut a peripheral neoprene sealing gasket and are held against the gasket by their own weight.

Abstract: A sealed shower system applies shower water to a pulp mat as it passes through a sealed chamber under a vacuum with an air supply that is externally regulated. The shower water forms a pond or film on the pulp mat. The amount of entrapped air is minimized through a downleg of a filter drum which results in maximum filtrate flow, an increased drainage rate, higher efficiency washing and a requirement for less shower water per pound of pulp. In addition, with less entrapped air in the filtrate, the length of the downleg can be reduced enabling lower building heights, smaller filtrate tanks and foam handling systems. The sealed shower system also forms part of a combined shower/hood structure that greatly reduces exhaust emissions.

Abstract: The apparatus is a washer, thickener and classifier for recovering solids from liquids including a truncated conical screen with walls typically sixty degrees from the horizontal and formed of filter media. Stock sprayer assemblies rotate about a longitudinal axis of said conical screen and direct stock, particularly deink paper stock, onto the walls of the conical screen. Wash fluid sprayer assemblies, including high impact shower nozzles, direct wash fluid onto the stock on the walls of the conical screen. The wash fluid cleans the stock, with the unwanted solids and contaminants passing through the conical screen to the discharge pipes. The wash fluid similarly washes the cleaned stock through the exit formed at the truncated portion formed at the apex of the conical screen for subsequent processing.

Abstract: A process for bleaching wood pulp is provided comprising subjecting the wood pulp, after brown stock washing, to an oxygen delignification stage, a washing sequence, a first chlorine dioxide bleaching stage, an oxidative extraction stage, at least one final chlorine dioxide bleaching stage and then recycling the filtrate from the oxidative extraction stage countercurrently through the bleaching plant and brown stock washing. Additionally, and quite beneficially, the filtrate from the first chlorine dioxide bleaching stage is also recycled countercurrently through the brown stock washing thereby significantly reducing the environmental impact associated with the manufacture of bleach wood pulp.

Abstract: The present invention relates to a digester for continuous cooking, under elevated pressure and temperature, of fibre material in a vertical digester (1), where fibre material and cooking liquid are fed into the top of the digester, used cooking liquor is drawn off from at least one digester screen arrangement (1D) between the top and the bottom of the digester, and fibre material is fed out from the bottom of the digester, it being possible to maintain the temperature in the cooking zone immediately above the digester screen arrangement (1B) at essentially the same temperature level as the remaining cooking zone or cooking zones of the digester.

Abstract: Apparatus for treating pulp, comprising a stand (1); a rotatably mounted drum (3); feeding and discharging members (6, 8) for the pulp; a wall member (2) which surrounds the jacket (40) of the drum in order to delimit therebetween a material space (5) with which the feeding member communicates via an inlet (7), which material space includes two treatment zones (24, 25); a delivery member (26) for delivering liquid to the treatment space via the wall member; a press member (22, 23) arranged downstream of each delivery member in order to exert a press force against the pulp; a collecting chamber (18, 19) inside the drum in connection with each treatment zone and press member for receiving liquid which is pressed through the jacket. According to the invention, the drum is supported by two support rollers (12, 13) which extend through the drum on either side of its vertical center plane and are in contact with the inner side of the drum, the support rollers being rotatably mounted on the stand (1).

Abstract: The present invention relates to a device for distributing liquid, especially washing liquid for washing paper pulp, in a diffuser having at least one screen plate (1), comprising an apparatus for supplying the washing liquid and at least one elongated nozzle (2, 5) which can be connected to the apparatus and which extends down in front of the screen plate and is arranged to supply the liquid. The nozzle is provided with openings (7 to 12) for washing liquid which open out at different predetermined levels, and whose location is designed to provide an even distribution of washing liquid along the height of the screen plate. A channel (13 to 18) for supplying washing liquid can be arranged to each opening (7 to 12) in the nozzle (2, 5).

Abstract: A post-digestion treatment method for cellulosic pulps which reduces the generation of dioxins and other chlorinated organics in the pulp, treatment effluent and/or the paper product produced from the pulp. In the treatment, the pulp, following digestion, is washed with a liquid that is essentially free of dioxins or dioxin precursors and simultaneously adjusted in consistency to at least a medium, and preferably a high consistency. Thereafter, the pulp is contacted with a chlorination agent selected from the group consisting of gaseous chlorine dioxide, gaseous chlorine, and gaseous chlorine dioxide which contains a minor amount of gaseous chlorine.

Abstract: A process for bleaching wood pulp is provided comprising subjecting the wood pulp, after brown stock washing, to an oxygen delignification stage, a washing sequence, a first chlorine dioxide bleaching stage, an oxidative extraction stage, optionally at least one final chlorine dioxide bleaching stage and then recycling the filtrate from the oxidative extraction stage counter-currently through the bleaching plant and brown stock washing. Additionally, and quite beneficially, the filtrate from the first chlorine dioxide bleaching stage is also recycled counter-currently through the brown stock washing thereby significantly reducing the environmental impact associated with the manufacture of bleach wood pulp.

Abstract: The apparatus is a washer, thickener and classifier for recovering solids from liquids including a truncated conical screen with walls typically sixty degrees from the horizontal and formed of filter media. Stock sprayer assemblies rotate about a longitudinal axis of said conical screen and direct stock, particularly deink paper stock, onto the walls of the conical screen. Wash fluid sprayer assemblies, including high impact shower nozzles, direct wash fluid onto the stock on the walls of the conical screen. The wash fluid cleans the stock, with the unwanted solids and contaminants passing through the conical screen to the discharge pipes. The wash fluid similarly washes the cleaned stock through the exit formed at the truncated portion formed at the apex of the conical screen for subsequent processing.

Abstract: Apparatus for the operation of a plant for producing deinked pulp with state analysers constructed in the form of neural networks for the waste paper suspension.At least one measuring device (ME) records spectral and/or physical characteristic values (IMf, Mp) of a waste paper suspension (PS). Furthermore, there are closed-loop or open-loop control devices (RS1 . . . RS8) for operating means of a waste paper preparation (AAA) in the plant. According to the invention, there is at least one state analyser (ZA), configured in the form of a neural network (NNg) or a plurality of parallel neural networks (NN1 . . . NN4), for the waste paper suspension (PS). This analyser forms from the characteristic values (IMf, Mp) controlled variables (ST: AB, AZ, FL, AA, AS, AT) for process control of the closed-loop or open-loop control devices (RS1 . . . RS8) of operating means at least of the waste paper preparation (AAA).

Abstract: The invention relates to a diffuser having a substantially cylindrical container through which cellulose pulp is arranged to be transported, nozzle arms for delivering a fluid to the pulp, a scraper arm with scrapers spaced apart from the nozzle arms, and concentrically disposed screen surfaces and screen arms disposed on and connected to the screen surfaces for withdrawal of the fluid. The screen arms are provided, at their outer ends, with fixed, non-pivotal withdrawal pipes that are slidably controlled and are connected in sealing arrangement to filtrate outlets. The screen arms have interior withdrawal areas with increasing cross-sectional areas as the screen arms extend toward the withdrawal pipes. The screen arms also include long and short plugs for controlling the filtrate flow capacity of the diffuser.

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

Abstract: A system for dewatering/washing wood pulp and also for bleaching the same. Pulp from a digester is directed into a dewatering/washing apparatus which comprises a high pressure vessel in which there is a table assembly having a perforate support surface for receiving the pulp thereon. A pressure differential is applied across the table assembly so that liquid is removed from the pulp. Also, a processing chemical and/or compound for bleaching is directed into the pulp at a final stage in the washer so as to be retained in the pulp. The pulp is then directed to a pressurized processing vessel where the compound and/or chemical reacts with the pulp. The pulp so treated in the processing vessel is then directed through a second washing station where the pulp is dewatered and has a compound and/or chemical introduced thereon, after which the pulp is transmitted to a second pressure vessel. This process is continued until the bleaching process is completed.

Abstract: Arrangement for a continuous diffuser for washing pulp, comprising a number of hydraulic cylinders distributed in a ring, arranged so as to repeatedly raise and then lower a screen assembly which is included in the diffuser. The characterizing feature of the invention is that groups of two or more hydraulic cylinders which lie adjacent to each other in the ring are coupled in parallel with each other, but in series with the next group of adjacent hydraulic cylinders which are also coupled in parallel, so that each group of parallel-coupled hydraulic cylinders is coupled in series with the next group of parallel-coupled hydraulic cylinders.

Abstract: The present invention provides a concentrated washing machine having a rotatable cylindrical drum made of punched metal. The drum has an inner surface lined with wire mesh and the drum is housed within a case body. A handle-shaped end plate, which is equipped with radial ribs, is provided at one end of the cylindrical drum. The other end of the cylindrical drum is open. The end plate has a wire mesh lining and is equipped with a suitable number of vanes. Extending into the open end of the cylindrical drum are: a wire mesh cleaning nozzle; a paper stock charge pipe for spraying onto the vanes; a pipe with numerous holes for spraying cleaning water onto the vanes, and a replenishment wetting water pipe. The handle-shaped end plate equipped with radial ribs and a wire mesh lining is provided at one end of the drum to increase the filter area and thereby improve the washing efficiency. The vanes agitate the paper stock by rotational movement to greatly improve the washing efficiency.

Abstract: A method of papermaking having zero liquid discharge. A cellulosic pulp composed of recycled materials is initially cleaned to remove contaminants and foreign material, and the clean pulp is then washed to remove dissolved solids and pulping chemicals, and the washed pulp is then utilized in the papermaking process. The contaminants are separated from the liquid residue resulting from the pulp cleaning operation, preferably by floatation clarification, and the effluent from the clarification is evaporated to produce steam or water vapor along with an evaporated residue. The evaporated residue is combined with the suspended solids that were removed from the liquid residue and the combined residue is then subjected to a mechanical dewatering operation to reduce the water content so that the dewatered material can then be either landfilled or incinerated. The condensate from the evaporation can be combined with fresh makeup water and used in the papermaking process.

Abstract: A method of washing cellulosic pulp to remove dissolved solids as well as dirt, inorganic fillers and fiber debris. A mat of cellulosic pulp having a weight of 3 to 100 lbs. of dry fiber per 1000 sq.ft. is positioned between a pair of porous endless belts to provide a composite structure. The composite structure is moved in a generally vertical path of travel through a vessel containing a plurality of superimposed rolls and the composite structure is passed over the rolls in a manner in which a first of the belts is in direct contact with one roll and the second of the belts is in direct contact with the next adjacent roll. A stream of water is directed against the composite structure as it travels in the upper portion of the vessel, and the water is cascaded downwardly through the vessel and directed into contact with opposite sides of the structure to thereby remove dissolved solids, as well as inorganic fillers. The tension of the belts as they pass over the rolls creates a dewatering action.

Abstract: In a pulp washing method which employs a dilution stage, followed by an extraction stage, and followed, in turn by a dilution stage, filtrates from the extraction stage and the displacement stage are segregated so that at least a part of the filtrate from the extraction stage may be removed from the pulp washing.

Abstract: Liquor removal from particulate solids such as wet wood pulp is achieved by applying a pneumatic or vapor pressure force through a pad of the wood pulp to compress the solids and to expel liquor from the solids. If air is used as a displacing medium, no wash liquor is added and the solids are simply compressed and some of the liquor is replaced by the gas passing through the suspension. If steam is used, not as a heating medium but as a pressure medium, an increase in liquor removal occurs over and above that removed by gas only due to the condensation of the steam to form a liquid front travelling before the steam through the solid suspension. Hence, in principle, a combination of pressure washing and displacement occurs resulting in a high efficiency in washing. Gas or steam could therefore simply be applied to any conventional operation to increase the washing efficiency both by compression and by displacement.