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: The invention relates to a process for bleaching preoxidized paper pulp enabling a pulp having a very high degree of whiteness to be obtained with a limited number of treatment steps and enabling pollution to be reduced without degrading the qualities of the pulp; such a process essentially comprises the combination of the three successive treatment steps, namely:(a) a first step of hot chlorination with gaseous chlorine at a temperature of between about 30.degree. and 80.degree. C., and preferably between 35.degree. and 50.degree. C., in the presence of urea used at a rate of 0.5 to 5% by weight of the chlorine used, and preferably from 1 to 3%, with a concentration of pulp of between 3 and 30%, and a duration of retention of the chlorine of 30 seconds to 45 minutes;(b) a second step of alkaline extraction in the presence of an oxidizing agent of the hypochlorite or peroxide type, at a temperature of between about 30.degree. and 70.degree. C., and at a pH of between about 8 and 12, and preferably between 10.

Abstract: A process is provided for continuously washing fibrous suspensions in aqueous suspending liquors containing dissolved impurities to remove such impurities by exchanging aqueous suspending liquid substantially free from such impurities for the aqueous suspending liquor, which comprises washing fibrous material of the suspension in aqueous suspending liquid substantially free from dissolved impurities; and forming a washed fibrous suspension in such liquid; withdrawing aqueous suspending liquor containing dissolved impurities; diluting the washed fibrous suspension by adding aqueous suspending liquid substantially free from dissolved impurities; measuring the volume amount of such diluting aqueous suspending liquid added; measuring the volume amount of diluted washed fibrous suspension; and then adjusting the volume amount of wash liquid added to maintain substantially constant the difference between the amount of wash liquid added and the liquid content of the undiluted washed fibrous suspension.

Abstract: Sorbed sodium ions in the wood pulp are recovered in the washing operation following cooking with the minimum use of pH control acid, thereby reducing cost and any possible undesirable side effects. A washing press is used in the pulp process. Means are provided for adding an acidifying chemical to the washing press for controlling pH of the pulp suspension. The filtrate from the washing press is divided, with the larger portion of the filtrate being fed to the pulp suspension line to the washing press for pulp suspension pH control. A smaller portion of the filtrate is fed countercurrently through the brown stock washing system. The chemicals are then recovered from the brown stock washing system filtrate.

Abstract: A method and apparatus for the treatment of fiber material by oxygen bleaching. Digested cellulosic fiber material is treated with oxygen to reduce the Kappa number thereof further to about 15 or below. The reaction products are removed immediately after formation, and during the oxygen bleaching process. The fiber material is at a first consistency of about 8 to 15% consistency, and treatment with oxygen is accomplished by mixing the pulp with O.sub.2, NaOH solution, and water to thereby form an integral mixture of pulp with oxygen at a second consistency, thickening the integral mixture to return it to generally its first consistency, and repeating the mixing and thickening until pulp of a desired Kappa number (15 or below) is reached. The pulp is then washed and may be subsequently treated to reduce the Kappa number thereof to any desired value. A thickener is used which can thicken pulp at superatomspheric pressures and at a temperature greater than 100.degree. C.

Abstract: A versatile process and apparatus is presented for producing, in high yields, many different grades of pulp from a single wood specie or for pulping any specie or type of woody material, and for storage and recycling of the by-product liquid and gaseous materials. The process of this invention is virtually pollution free, and the reactant chemicals are recoverable from the by-products. In the alternative, the by-products themselves have a commercial value which may forestall recovery of the reactants. The lignin constituent extracted from the pulp is usable as a resin binder, a wood rehardening agent, or a glue.

Abstract: A method is provided for reducing waste stream pollutants by the control and separation of color bodies, COD, BOD and other organics from inorganic chloride pollutants in the aqueous waste effluent of a cellulosic pulp bleaching process containing a sequential chlorination stage (D.sub.c) or mixture (D/C) stage followed by an extraction (E) or oxygen (O) stage, comprising, maintaining the conditions of the D.sub.

Abstract: A process is provided for the chemical refining of cellulose pulp which comprises, in sequence, the steps of:(1) impregnating the cellulose pulp with refining chemicals in an amount selected to effect chemical modification of the pulp;(2) adjusting the pulp consistency to within the range from about 30 to about 70%; and(3) passing the pulp in turbulent flow through an elongated reaction zone from one end to another end thereof in a gaseous atmosphere consisting essentially of steam and preferably containing less than 1% by volume of oxygen at a superatmospheric pressure within the range from about 5 to about 400 kPa and a temperature within the range from about 100 to about 150.degree. C. at which the chemical modification proceeds without a mechanical working sufficient to change the degree of beating of the pulp by more than about 2.degree.

Abstract: A multi-stage, bleaching process for alkaline cooked pulps, including at least four bleaching stages and no more than three washing steps, is provided, wherein certain of the bleaching stages are shortened to less than about 15 minutes.

Abstract: Disclosed is a process and apparatus for wetting textile fibers and the like. The process comprises supporting a mass of fiber to be wetted upon an air and water permeable support, the support being mounted between the closed bottom and the open upper end of a kier or the like. With a mass of fiber in place, liquid such as water or the like is applied to the top of the mass of fiber. This forces the occluded air out of the fiber in a downward direction and this air is removed from beneath the support. The disclosed apparatus is capable of carrying out the foregoing process. Essentially, the kier is provided with a vent to atmosphere just below the bottom of the support. A supply of liquid is maintained in the bottom of the kier and a pump is provided to supply this liquid to the top of the mass of fiber, for wetting the same.

Abstract: A de-inking composition is disclosed consisting substantially of:(A) a salt of a fatty acid of the formula: R--COO--M wherein R represents one or more hydrocarbon chains selected from the class consisting of saturated and/or unsaturated hydrocarbons; and M represents a metal selected from the class consisting of Na and K; said fatty acid salt being present in an amount between 5% and 32% with respect to the weight of the entire composition;(B) a non-ionic ethoxylated and/or propoxylated surfactant of the formula: ##STR1## wherein: Y is either H or CH.sub.3 ;R.sup.1 O represents the hydrophobic moiety of the molecule and is derived from a compound selected from the class consisting of alkylphenols of formula ##STR2## saturated primary fatty alcohols of formula R"--CH.sub.2 OH; saturated secondary fatty alcohols of formula R"' ##STR3## fatty acids of the formula R.sup.v --COOH; and mixtures thereof, wherein R', R", R"', R.sup.iv and R.sup.

Abstract: A method and apparatus for the delignification of cellulosic fiber material to minimize the amount of reject material in the final pulp produced. The fiber material is digested, washed, oxygen delignified, and passed through a screening stage to provide a main pulp stream, and a reject stream from the separation stage. The flow and consistency of the separated reject material is determined, the reject material is refined, and sufficient chemical is added to the separated reject material, based upon the flow and consistency thereof, so that subsequent delignification of the reject material may be effected. This may be accomplished either by passing the reject material through a separate oxygen delignification stage and then returning it to the main pulp stream, or adding caustic to it and soaking it in a soak tank for predetermined period of time, and then returning it to the main pulp stream before the oxygen delignification stage therein.

Abstract: A process and apparatus for washing high consistency fibre stock in the de-inking of paper. Grey stock is passed along a passage from a grey stock inlet to an outlet for cleaned stock. The passage is defined by a filter screen preferably of wire gauze. Within the passage is disposed a stirring member. Washing liquid such as water is introduced into the passage preferably by means of apertures in a central portion of the stirring member. Effluent liquid passes through the screen for extraction through a suitable outlet, or for recirculation. The arrangement is such that relative rotation of the screen and member results in clusters of stock fibres, which move around the passage as they pass therealong. The stirring member preferably includes a plurality of longitudinally extending, axis parallel bars radially spaced from the central portion.

Abstract: A method of controlling the amount of a liquid shower flow introduced onto a slurry mat such as a pulp mat which is undergoing incomplete liquid separation on a vacuum filter drum. The flow rate of the liquid being discharged with the slurry mat is determined by a capacitance measurement which is taken after the slurry mat has passed to a point on the filter means where liquid separation no longer occurs. The shower flow is controlled by a correlation of the flow rate of the liquid in the slurry mat with the rate of slurry mat transfer from the vacuum filter drum and the necessary liquid shower flow as expressed by a dilution factor.The present control system may be combined with secondary apparatus to measure the flow rate and thickness of the total slurry mat in order to determine by correlation the slurry mat consistency, the rate of solid material production from the slurry mat and the amount of air contained in the slurry mat.

Abstract: An improved washer for removing impurities or other substances from a porous mat disposed over a vacuum head. As disclosed, in connection with an industrial paper making process, the porous mat is paper pulp and an elongate chamber, disposed axially above the drum, has a slot along its bottom with resilient downwardly extending skirts disposed around the edges of the slot. Water under pressure in the chamber is directed downward, and into the pulp mat. The resilient skirts prevent the wash water from flowing tangentially with respect to the mat so that the flow of water into the mat is essentially perpendicular to the mat. The chemicals within the mat are positively displaced by relatively clean wash water.

Abstract: A method and apparatus for screenless treatment of cellulose fiber material without channeling of treatment liquid through a fiber material column being treated. An inner vertical vessel extends into an outer vertical vessel which has a larger diameter than the inner vessel, and an annular space in the outer vessel is defined by a portion of the inner vessel extending into the outer vessel. At least three baffles extend through the annular space into the area of the outer vessel below the inner vessel to define at least three distinct flow areas, and an outlet nozzle is provided in each of the flow areas. Liquid is withdrawn from the annular space through at least two of the flow areas, while liquid is backflushed into one of the flow areas.

Abstract: A pulp mill bleach plant operation having a low effluent volume, a low consumption of water, energy and chemicals, and yet provides efficient bleaching, caustic extraction and washing is described. Water conservation is practised by controlling the use of wash water in the bleach plant, controlling the design and operation of washers, deckers and other mechanical devices used in the bleach plant and controlling the inflow of water with chemicals. An aqueous polluting effluent-free pulp mill water utilization system is also described.

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: This invention relates to a process in which a liquid A is displaced by a liquid B in a suspension. This is effected by superimposing a liquid column on an exchange chamber through which the liquids flow in countercurrent, with stirring. The process may be used for washing or acidifying suspensions, particularly cotton linters.

Abstract: This invention relates to a process for multi-stage alkaline pulping of ligno-cellulosic raw materials and recovery of delignification spent liquors, i.e. black liquor from digestion with white liquor and oxy-liquor comprising bleach plant effluent extracted from alkaline oxygen delignification of brown stock.According to the invention, oxy-liquor and intermediate black liquor in the digester are passed through that part of the material column to which the cellulosic raw material, e.g. wood chips, enters. There, hydroxide deriving from two sources, white liquor and oxy-liquor, is exhausted prior to its discharge as terminal black liquor. White liquor is consequently injected to the level of the pre-digested material in the column. This injection is controlled by continuous measurement, e.g. by automated titration analysis, of the hydroxide concentration in the joint volume of oxy-liquor and white liquor in the main cooking liquor circulation system.

Abstract: A horizontal, Fourdrinier foraminous belt type, countercurrent, high-capacity, cellulose pulp washer is described. The described washer is equipped with a hood positioned over a portion of the belt and over vacuum boxes or receptacles under the upper loop of the belt. The gases and vapors drawn into the vacuum boxes or receptacles with the wash liquid are separated from the liquid in the receptacles and recycled to the hood to control the atmosphere in the hood and maintain the desired pressure differential for operation of the washer.

Abstract: A process and apparatus are provided for controlling the supply of aqueous suspending liquid in continuously washing fibrous suspensions in aqueous suspending liquors containing dissolved impurities, to remove such impurities by exchanging aqueous suspending liquors substantially free from such impurities for the aqueous suspending liquor, which comprises washing fibrous material of the suspension in aqueous suspending liquid substantially free from dissolved impurities, and forming a washed fibrous suspension in such liquid; withdrawing aqueous suspending liquor containing dissolved impurities; diluting the washed fibrous suspension by adding aqueous suspending liquid substantially free from dissolved impurities; determining the amount of dissolved impurities remaining with the fibrous suspension after the washing has been completed by measuring (1) the volumetric flow rate of the washed suspension; (2) the liquid content of the washed suspension; and (3) the content of dissolved impurities in the suspending

Abstract: An apparatus and method for the treatment of cellulosic fiber material with maximum efficiency while minimizing capital costs. Fiber material entrained in digesting liquid is impregnated with the liquid in an impregnation vessel, sluiced to a separate digesting vessel, and from the digesting vessel sluiced to one or more separate washing vessels without a significant reduction in pressure. Countercurrent washing is effected in the washing vessel(s). Digesting liquid withdrawn from the digesting vessel is heated in a transfer line back to the impregnation vessel.

Abstract: A method of removing liquid from a slurry of solid material in liquid in which the liquid is squeezed from the slurry by passing the slurry through a roll nip and, simultaneously with the squeezing and passing, the liquid squeezed from the slurry is blocked from flowing through the roll nip.Apparatus for removing liquid from a slurry of solid material in a liquid includes a plurality of liquid guides, disposed in a spaced-apart parallel relationship, being inclined away from and opening adjacent the roll nip.

Abstract: A pulp mill bleach plant operation having a low effluent volume, a low consumption of water, energy and chemicals, and yet provides efficient bleaching, caustic extraction and washing is described. Water conservation is practised by controlling the use of wash water in the bleach plant, controlling the design and operation of washers, deckers and other mechanical devices used in the bleach plant and controlling the inflow of water with chemicals. An aqueous polluting effluent-free pulp mill water utilization system is also described.

Abstract: A technique for controlling the amount of dissolved material in a slurry liquid stream containing dispersed particulate solids which is being continuously processed in a zone of countercurrent particulate solids separation and washing. Flow rates and conductivity measurements are made on streams entering such zone which are then used to estimate the amount of dissolved material in a starting slurry liquid. Preferably, conductivity measurements are made with electrodeless conductivity measuring probes. The technique is well adapted for use in a brown stock washing system employing a plurality of counterflow washers. The technique can be used for measurement of the quantity of gas in an agitated process stream in such a zone.

Abstract: A process is provided for the delignification of lignocellulosic material wherein the lignocellulosic material, prior to the delignification, is treated with water or an aqueous solution to remove compounds which catalyze the degradation of carbohydrates and then the delignification is carried out with oxygen and alkali in the presence of a manganese compound to improve the selectivity of the delignification and increase the rate of delignification.

Abstract: Particulate lignocellulosic material, having a moisture content of about 10-80 weight percent, is treated at temperatures below about 50.degree. C. with 2 to 8 weight percent nitric oxide based on the weight of dry lignocellulosic material. Thereafter, said nitric oxide treated material is reacted with molecular oxygen to form nitric acid in situ. This reaction is followed by washing of said material with alkali and extraction of said material with alkali at a temperature above about 140.degree. C. to delignify the lignocellulose and form pulp.

Abstract: A process for purifying the effluent from a pulp bleaching process which includes a chlorine treatment, an alkali extraction, and a final bleaching is disclosed, wherein a number of washing steps are connected in counter-current series from a final wash step in the final bleach section to the wash step of the first alkali extraction stage, the strongly polluted effluent from the wash step of the first alkali extraction stage is passed through a first column containing a bed of particulate porous resin which traps and retains organic pollutants in the effluent, and a combined effluent which includes an acidic polluted liquor from the chlorine bleaching stage and a partly purified filtrate from the first column is fed through a second column which contains a bed of particulate porous resin which traps organic pollutants fed therethrough, with the resin bed in the second column being activated by the acidic nature of the combined effluent, with chloride ions in the combined effluent essentially passing through t

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: Process for improving the selectivity of delignification of lignocellulosic material in the presence of oxygen gas and alkali by maintaining a carbon monoxide content in the gas phase within the range from about 1% to about 12% by volume. The carbon monoxide concentration is maintained by withdrawing carbon monoxide and oxygen gas from the delignification, and separating and recycling withdrawn oxygen gas.

Abstract: A slurry of cellulosic material is diluted to a flowable consistency and subjected to a pressure differential on a permeable surface to increase the slurry consistency to a value between the consistency of the diluted slurry and the consistency of the slurry prior to dilution thereby forming a mat of cellulosic material on the permeable surface. The liquid and solids which pass through the permeable surface as a result of the pressure differential are recycled for use as slurry diluent, and to the mat of cellulosic material, while the mat remains on the permeable surface and subject to the pressure differential, is countercurrently applied, in a plurality of treatment stages, a treating liquid, such as a wash liquid, including application of a fresh treating liquid to said mat in the last stage of said treatment stages, whereby the treating liquid displaces at least a portion of liquid present in said mat from said mat and through the permeable surface in each treatment stage.

Abstract: A process for washing a cellulose pulp from alkali digestion, wherein the pulp is fed into a multistage washing system comprising several countercurrently coupled washers, acid is added to a washing solution, the acidified fiber suspension is fed further to the following stage wherein the acidified solution is replaced in the fiber suspension by washing water, and the filtrate obtained from this stage is used after acidification at least partially as a washing solution at the previous stage. The acid is added at a stage when the concentration of the dissolved organic substances is at a value that detrimental precipitation of the organic substances is prevented.

Abstract: A method and apparatus for the thickening of a suspension of comminuted fiber material and liquid. A reciprocal screen assembly having a variable volume interior chamber is mounted for movement along the axis of a container through which suspension to be dewatered flows. Mechanical apparatus, such as a hydraulic cylinder actuated rod, moves the screen assembly in either the direction of flow of suspension in the container, or in the direction opposite thereto, and the screen assembly is relatively rotatable with respect to the container. During movement of the screen assembly in the direction of flow of the suspension (at about the same velocity as the suspension flow), liquid passes through the screen assembly into the interior chamber, and is expelled from the container. The screen assembly is moved more quickly in the direction opposite to the direction of suspension flow, and the variable volume of the interior chamber thereof decreases quickly so that backflushing of the screen assembly is effected.

Abstract: Acid and alkaline filtrates are separated from the bleach plant of a bleached pulp mill for use in washing unbleached pulp free from entrained pulping liquor. Acid effluent is neutralized with sodium hydroxide solution prior to use in the washing as the last washing step while alkaline filtrate is used in the remainder of the washing. Part of both the acid and alkaline filtrates are not used in the washing to allow bleed of calcium value and caustic extraction stage solids which otherwise would build up on the washed pulp mat passing to the bleach plant.

Abstract: Water-dispersible defoamer compositions comprise an intimate blend of a mixture of defoaming components and at least one emulsifier to impart water-dispersibility to the composition. The defoaming components include a monoester of an alkenylated succinic acid, a particular organo-phosphorus compound and a silicone oil. The defoamer compositions have particular use in pulp mill defoaming compositions.

Abstract: A slurry of cellulosic material is diluted to a flowable consistency and subjected to a pressure differential on a permeable surface to increase the slurry consistency to a value between the consistency of the diluted slurry and the consistency of th slurry prior to dilution thereby forming a mat of cellulosic material on the permeable surface. The liquid and solids which pass through the permeable surface as a result of the pressure differential are recycled for use as slurry diluent, and to the mat of cellulosic material is applied a treating liquid, such as a washing liquid.