Abstract: An improvement in a chemical recovery process in which a hot liquid smelt is introduced into a dissolving tank containing a pool of green liquor. The improvement comprises preventing smelt explosions in the dissolving tank by maintaining a first selected superatmospheric pressure in the tank during normal operation of the furnace; sensing the pressure in the tank; and further impinging a high velocity stream of steam upon the stream of smelt whenever the pressure in the tank decreases below a second selected superatmospheric pressure which is lower than said first pressure.

Abstract: A method of recovering alkaline chemicals from a material containing sodium or potassium compounds. The material is gasified by an external heat source after which the gas is rapidly cooled by arranging it to contact with cooled solid particles separated from the gas.

Abstract: Described herein is a process for producing potassium salts from potassium-based liquors for pulping of lignocellulosic material. The process comprises the steps of(a) digesting lignocellulosic material with a potassium-base aqueous cooling liquor to obtain an aqueous slurry of partially delignified pulp of the lignocellulosic material;(b) separating the pulp from the spent potassium-base aqueous cooling liquor;(c) concentrating the spent pulping liquor; and(d) recovering potassium salts including potassium carbonate, potassium sulphate and potassium lignosulphonate from the concentrated spent pulping liquor. The recovered potassium salts find numerous uses, an example being use in fertilizers.

Abstract: A method for forming a paper web by which web formation is improved and flocculation in the web is reduced includes the steps of feeding steam under pressure into the fiber suspension when the suspension enters into the gap of the former and as web formation is initiated over the perforated mantle of the forming roll. The steam is fed from a steam supply chamber or the like provided within the forming roll through the perforations in the roll mantle within a steam supply sector of the roll mantle. The steam feed is applied to the pulp web when the web is still substantially uncouched and in a manner such that when the steam condenses in the pulp suspension, an implosion is generated in the pulp suspension which produces high frequency mechanical vibrations which can be closely controlled to achieve the desired effects. A twin-wire former and forming roll therefor for applying the method are also disclosed.

Abstract: A high solids black liquor having the property of reduced turbulent flow/drag comprising a high solids black liquor which contains a few parts per million of a water soluble terpolymer containing the repeating units in the following mole percentages: ##STR1## wherein R is a lower alkyl group from 1-6 carbon atoms, M is H or alkali metal, said terpolymer having a Reduced Specific Viscosity of at least 25.

Abstract: All of the essential operating parts for converting an existing Fourdrinier paper machine into a top former are carried by a supplemental frame assembly which can be mounted on the main Fourdrinier frame with no modification of the latter except the addition of a pair of pivotal mountings and a pair of adjusting jacks for the supplemental frame assembly. The primary operating parts of the top wire assembly are a hollow foraminous roll and a top deflector which cooperate to collect and deliver liquid extruded through the top wire into a receptacle which is carried by the supplemental frame assembly. Provision is also made for operating the resulting top former in roll formation mode, blade formation mode, or a combination roll and blade formation mode.

Abstract: A partially-oxidized spent pulping liquor is produced which is added to unoxidized strong spent pulping liquor prior, during, or subsequent to concentration to form a novel partially-oxidized, concentrated, high total solids spent pulping liquor. This novel, partially-oxidized, concentrated spent liquor is capable of being combusted in a spent liquor recovery furnace without the addition of auxiliary heating fuel with a resultant increase in the effective capacity of that furnace.

Abstract: The present invention relates to a twin wire former. It aims at resolving the difficulties with respect to the retention of fine raw material and the coupling strength in the thicknesswise direction of a paper sheet without deteriorating the formation and without causing problems associated with high speed operation. A top wire (34) is partly provided with a portion in which a water-impermeable belt (35) travels along the inside of its loop. Dewatering in this portion is effected only on one side, that is, on the side of the bottom wire (33). Also in this portion, wrapping angles for the wires (33) and (34) are varied by adjusting the positions of a plurality of rolls (3), (17) and (23) or shoes (14) and (18) to improve the formation, and thereafter, dewatering on the side where dewatering has been suppressed by the above-mentioned belt (35) is also effected.

Abstract: The present invention relates to a method and means of increasing capacity and improving the chemical recovery process when using a conventional soda recovery boiler for recovering chemicals out of spent sulphate liquors. The spent sulphate liquor is supplied in full or in part to a liquor gasifier (8) while external energy independent of combustion is simultaneously supplied (at 16, 17). The temperature and oxygen potential are carefully controlled independently of each other by means of controlled supply of the energy. The product thus obtained is thereafter introduced in full or in part into a soda recovery boiler (1).

Abstract: A novel apparatus for uniformly dispersing paper raw material in a paper making machine, in which a dewatering limit member impermeable to water is provided for covering two wires travelling along a curved surface of a wire support and for providing an adjustable urging force against the support, and thereby a dewatering limit region is defined such that the interval between the support and the dewatering limit member is decreased and then increased in a wedge-like manner along the direction of travelling of the wires.

Abstract: Apparatus for the purpose of enabling a paper mill to determine the extent to which the performance and/or the product of an existing Fourdrinier paper machine in the mill will be improved by its conversion into a top former machine comprises a fractional version of top forming apparatus which can be readily combined with an existing Fourdrinier machine in such manner that a minor portion of the forming width of the machine will be converted to top forming operation. The apparatus makes it possible to produce, on an existing Fourdriner machine, a sheet of which a small integral portion is formed by drainage through both the primary wire and a top wire, while the remainder of the sheet continues to be produced in the same manner as before the top wire testing.

Abstract: The invention relates to the recovery of chemicals from waste liquor from wood pulp process, primarily black liquor, while utilizing energy liberated. Controlled total vaporization of the pulp waste liquor at high temperature and low oxygen potential is achieved by the external supply of energy. During the subsequent condensation and separation of melt or water solution is obtained which, without causticizing, can be used for the preparation of white liquor, and also an energy rich gas and mainly free from sulphur, consisting primarily of carbon monoxide and hydrogen.

Abstract: A twin-wire former for a paper machine which can produce paper of good formation over a wide range of basis weight and at a speed of wide variation essentially consisting of a top wire and a bottom wire. The bottom wire with a wet material thereon substantially horizontally travels. The top wire approaches the material from above and travels downward together with the bottom wire on the circumference of a supporting member provided in the loop of the bottom wire while pressing the material between the pair of wires. At the position of a force roll provided in the loop of the top wire, the pair of wires commence travelling upwardly through a suction box to a couch roll, where the pair of wires separate from each other. To adjust the wire contacting angle of the supporting member, and hence, to improve the formation of paper, each of a water receiver, the force roll and suction boxes and made movable.

Abstract: A method for controlling the combustion and reduction processes in a black liquor (B.L.) boiler of a paper pulp plant by influencing the feeding of black liquor to the B.L. recovery boiler by means of a B.L. gun. Characteristic of the method is that the average thickness of the layer of the B.L. flow, immediately after the black liquor has left the B.L. gun, is controlled to have a desired magnitude. The thickness of the B.L. layer is obtained in the form of an indirect measure which is defined as the droplet index (=DIX) and is constituted by a relationship between the viscosity, the density and the feed rate of the black liquor and by at least the shape and the opening area, of the B.L. gun.

Abstract: A closed press section of a paper machine in which a paper web leaving the wire section of the paper machine is passed, supported by a first upper fabric, through a first double-felted press nip formed by two hollow-faced rolls. The lower fabric in the first double-felted press nip is a second fabric which carries the web forwardly after the first press nip. The press section further includes a smooth-faced central roll against which at least two single-felt nips are formed, the press fabric in the first one of the single-felt nips being constituted by the second fabric. The web is detached from the second fabric and adheres to the face of the smooth-faced central roll and moves along therewith into the next single-felt nip. The press section is devoid of press rolls of the suction type with the first double-felted press nip being formed between two solid-mantle hollow-faced rolls.

Abstract: In a particularly simple construction a twin-wire papermaking machine possesses a reduced number of rolls as well as a compact arrangement. The foregoing and the greatest possible velocity of a through-passed paper web can be obtained by employing non-suction rolls, instead of suction rolls, in a pressing section of such papermaking machine, by upwardly entraining the paper web conjointly with a top or upper wire of a twin wire arrangement and by transferring the paper web to a pressing roll having a smooth surface, and furthermore, by providing at the pressing roll an extended or wide-nip supporting shoe by means of which the paper web is dewatered in an extended pressing nip zone. Advantageously, the dewatered paper web is taken off from the surface of the pressing roll in a downward direction and fed to a drying section of the papermaking machine. The drying section may be arranged below the pressing section and directly adjacent the bottom or lower wire of the twin wire arrangement.

Abstract: A readily adjustable shatter jet mechanism comprises a frame which rotatably and displaceably receives a fluid supply pipe assembly. The assembly includes a fluid supply pipe which is pivotally movable. A nozzle is connected to the pipe and can be rotated into one of a plurality of rotational positions. The assembly can be disengaged from the frame and reengaged with the frame at a different location so that the pipe and its nozzle can also be displaced with respect to the frame. In this way the fluid jet can be directed in a variety of directions toward a smelt stream to be broken up by the fluid jet.

Abstract: A twin wire paper former incorporating a forming shoe having a curved solid forming surface across which the forming wires pass with one of the wires in direct contact therewith and the other sandwiching the stock from which the paper is to be formed therebetween. The tension in the other wire drives water from the stock contained between the two wires, out through the other wire, and the shoe is vibrated thereby to reduce the friction between the wire contacting the shoe, to reduce wear of the contacting wire and to improve drainage.

Abstract: This invention is a process for recovering sodium hydroxide directly from black liquor. The process involves pyrolyzing the black liquor in the absence of oxygen to produce a product containing sodium carbide, and hydrolyzing the sodium carbide to form sodium hydroxide. The pyrolysis is carried out at about 4000.degree. F. using radiant energy.

Abstract: A lower wire loop of a paper machine has an initial single-wire portion of a dewatering zone defined by an initial portion of the wire of the lower wire loop, succeeded by an upper wire unit defining a twin-wire dewatering zone with a coinciding upper run of the wire of the lower wire loop. Dewatering occurs in the twin-water dewatering zone through the wire of the lower wire loop and the wire of the upper wire loop. The twin-wire dewatering zone is located above the level of the initial portion of the wire of the lower wire loop. A first dewatering element is a first forming shoe in the direction of the web run in the upper wire loop. The twin-wire zone curves in a first direction in a first sector on the first forming shoe so that dewatering occurs primarily through the wire of the lower wire loop. A second dewatering element is a second forming shoe following the first forming shoe and spaced therefrom in the lower wire loop.

Abstract: Pulping liquor, which has been pre-concentrated to at least 50 weight percent solids, is dried in a fluidized bed dryer to produce a solid in particulate form. In the fluidized bed dryer, pre-formed particulates are fluidized by a gaseous medium substantially of superheated, unsaturated steam, and additional heat is supplied to the fluidized bed by higher pressure saturated steam passing through heat-exchange tubing within the fluidized bed region. Pulping liquor is introduced into the fluidized bed where the superheated steam vaporizes a substantial portion of its water content. The fluidizing steam becomes substantially saturated during its passage through the region of the fluidized bed, and a substantial portion of this substantially saturated steam is used upstream to pre-concentrate the pulping liquor.

Abstract: A pollution free pulping process wherein a lignocellulosic material is subjected to various pulping and bleaching steps without the use of sulphur and chlorine. The system is a closed one thus minimizing energy and chemical requirements while permitting one to obtain a product having excellent physical properties.

Abstract: A web-forming section and method in a paper machine. The web-forming section includes a lower wire loop having an initial lower wire run constituting an initial single-wire dewatering zone of the web-forming section in which the web is dewatered through the lower wire, and an upper wire loop having a joint run with a subsequent run of the lower wire to form a two-wire dewatering zone of the web-forming section within which dewatering takes place substantially through the upper wire. A first open faced forming roll is situated within the upper wire loop so that the two-wire dewatering zone begins and curves upwardly in the region of the first forming roll. A forming shoe within the lower wire loop has a curved deck whose center of curvature is situated on the side of the lower wire loop and further guides the joint run of the upper and lower wires in the two-wire dewatering zone.

Abstract: A process in the forming of a paper web, the dewatering of the pulp web, and of the paper web being formed comprises feeding the pulp suspension jet from the slice of the headbox into a gap formed by two wires, the gap becoming narrower in the feeding direction of the pump suspension jet. Water is removed from the pulp web when the web is in compression between the carrying wire and the covering wire within the twin-wire forming zone, which begins immediately after the feeding gap. The twin-wire forming zone is curved towards the loop of the carrying wire with a curve radius which is selected large enough so that the wire tensioning pressure resulting from it and acting upon the pulp web becomes low and the water removed from the pulp web is not splashed from the inside surface of the wire loop by the effect of centrifugal force dependent upon the curve radius.

Abstract: The invention relates to the recovery of chemicals from waste liquor from wood pulp process, primarily black liquor, while utilizing energy liberated. Controlled total vaporization of the pulp waste liquor at high temperature and low oxygen potential is achieved by the external supply of energy. During the subsequent condensation and separation a melt or water solution is obtained which, without causticizing, can be used for the preparation of white liquor, and also an energy rich gas and mainly free from sulphur, consisting primarily of carbon monoxide and hydrogen.

Abstract: A machine for making a fiber web with sharply defined edges, specifically a paper or tissue web, between a felt and a wire, features a headbox that dispenses the fiber suspension into a feed-in area formed between the felt and wire. The wire has a smaller width than the width of the fiber suspension stream dispensed by the headbox.

Abstract: A roller is provided with ribs directed outwardly from its face which permit the formation of cavities between the circumferential surface of the roller and the screen belts entrained thereon so that continuous channels are formed on the circumferential surface of the roller which conduct the filtrate axially outwards. The ribs are hollow tubular members having an opening along the surface of the roller which captures additional liquid, preventing it from falling back onto the belt, and allowing it to be conducted off and drained by allowing the liquid to flow laterally only.

Abstract: A process for removing an anthraquinone type scale comprises condensing a steam evaporated from a black liquor obtained by separating pulp from a digested mixture of lignocelluloses containing an anthraquinone type digesting assistant; and contacting a heated aqueous solution of a base in the presence or absence of a reducing agent or an alkali resistant surfactant with a wall of a condenser of an evaporator on which said anthraquinone type scale is adhered.

Abstract: The invention relates to a method of recovering chemicals from chloride-containing green liquor by precarbonating the green liquor by means of flue gases into hydrosulfide and soda, by removing hydrosulfide from the precarbonated solution in the form of hydrogen sulfide, by evaporation crystallizing the chloride- and soda-containing solution in order to separate the chloride salt from the alkaline solution. In order to reduce releases of hydrogen sulfide, the produced hydrogen sulfide is absorbed into a soda solution and/or an alkaline solution in order to produce a solution suitable for the preparation of white liquor, whereas the hydrogen sulfide which remains unabsorbed is returned to the precarbonation stage, in which the hydrogen sulfide is absorbed substantially completely. By means of the invention it is possible to achieve a closed cycle of chemicals without the chloride load of the system increasing, and at the same time the chloride is recovered and returned to the bleaching.

Abstract: A forming roll positioned in the forming section of a Fourdrinier papermaking machine and supported above the forming medium in contact with one surface of a constituent material to sandwich the material between a substantial arc segment of the forming roll surface and the forming medium.

Abstract: An apparatus for affecting a web drained on a wire, comprising a lower wire which runs as an endless loop; disposed transverse members which supporting the lower wire, disposed at a distance from each other; an upper wire which runs as an endless loop and presses the web formed on the lower wire in the area between the supporting members. Inside the upper wire loop there is disposed a dewatering shoe which is in contact with the upper wire, and a roll which together with the dewatering shoe form a flow channel for leading upwards the water pressed out.

Abstract: A method and apparatus for forming a web wherein a fiber suspension from a head box is fed on a section of a forming wire formed by a first, substantially horizontal dewatering zone, and where the web being formed is thereafter led to a second dewatering zone where an upper wire is caused to cover said web, and both wires together with the web between them are led over a turning member. In the twin wire dewatering zone the wires bend upwards. After the turning member the web runs further linearly between the wires obliquely upwards. The web and the lower wire run around a pick-up suction roll and the upper wire leaves the web. The dewatering in the dewatering zones occurs only in one direction, i.e. through the forming wire.

Abstract: A method and apparatus for continuously producing pulp from previously unusable agricultural fibers, such as plantain. The pulp is used in papermaking. The pulp effluent is recycled and concentrated during the process, thereby enabling economical recovery of chemical by-products for use as fertilizer or animal feed material.

Abstract: The invention relates to an improvement in a dehydration machine for wood pulp, sludges, or similar fibrous material, composed of a lower strainer operating as a support strainer and an upper strainer operating as the cover strainer, which loop support and reversing rolls and are adapted to pass jointly with the material to be dehydrated coming from a material feed through a wedging section and through pairs of pressing rolls in a pressing section, the improvement comprising a laterally sealed wedging section arranged substantially vertically or at an incline, followed directly by a reversal means provided with a lateral seal, and the pressing section including a group of rolls which at the beginning contains a pair of first and second pressing rolls mounted next to each other, with a pressing roll contacting the second pressing roll.

Abstract: A filter press having a main press with an after-pressing device spaced from the outlet end of the main press which device carries out the final pressing and is composed of at least two press roll pairs (1,2), made up of rolls (3,4,5,6) between which the wires (7,8) belonging to the main press pass with the pulp (9) being filter pressed interposed between the wires and pressed by action of a pressing force (F) directed against the topside rollers (3,5) of the press roll pairs and produced by a force applicator such as a pressure cylinder (10). The pressure ratio (F.sub.1 /F.sub.2) between the topside rollers (3,4) and the bottom side rollers (5,6) is adjustable by the aid of a control setup.

Abstract: Apparatus and method for the manufacture of a non-woven fibrous web such as paper from a dispersion of fibers in a foamed liquid in which fiber furnished in a foamed liquid comprising a solution of surfactant in water is discharged from a headbox into the nip of a twin forming wire prior to its passage over a forming roll. The water-surfactant solution is drained from the web and recycled as a foamed liquid containing about 65% air in the form of bubbles of from about 20 to about 200 microns in diameter. The foamed liquid is directed into a mix tank wherein a slurry containing fiber at 20% to 55% solids is added and mixed. The mixture is pumped to the headbox and into the nip of the forming wires.

Abstract: A method for keeping the heating surfaces in the final thickener (VI), which is divided into several sections (A,B,C), clean in evaporating waste liquors in pulping processes for recovering the cooking chemicals. Chemical solutions e.g. residual products from other processes as tall oil separation and chlorine dioxide production are added to cover the chemical losses. According to the invention the chemical solutions are supplied to those sections of the final thickener which are at the time not being washed with thick waste liquor from the preceding evaporator (II).

Abstract: In a horizontal twin-wire paper machine, the paper sheet is initially formed in a wedge-shaped zone defined by generally horizontal runs of the primary wire and top wire which are brought into converging relation by cooperating sets of deflectors which support both runs against relative displacement by the stock therebetween and thereby cause liquid to be expressed through both of the wire runs throughout the wedge zone. The converged wires with the newly formed sheet therebetween then travel partially around one or more imperforate forming rolls, after which the top wire is guided away, and the sheet continues its travel on the primary wire. A major feature is the ease and simplicity with which the structure for supporting the top wire and the elements for defining the wedge zone can be added to an existing Fourdrinier machine to convert it to a twin-wire machine.

Abstract: An integrated apparatus and process for recovery of heat and chemical values from spent pulping liquors are disclosed. Novel means for recovering heat values and residual entrained solids from the combustion gases are provided.

Abstract: A closed press section of a paper machine in which a paper web leaving the wire section of the paper machine is passed, supported by a first upper fabric, through a first double-felted press nip formed by two hollow-faced rolls. The lower fabric in the first double-felted press nip is a second fabric which carries the web forwardly after the first press nip. The press section further includes a smooth-faced central roll against which at least two single-felt nips are formed, the press fabric in the first one of the single-felt nips being constituted by the second fabric. The web is detached from the second fabric and adheres to the face of the smooth-faced central roll and moves along therewith into the next single-felt nip. The press section is devoid of press rolls of the suction type with the first double-felted press nip being formed between two solid-mantle hollow-faced rolls.

Abstract: A forming shoe in a two-wire forming section of a paper making machine has a curved guiding surface which guides a joint run of the wires and web interposed therebetween over a curved path of travel wherein the web is dewatered under the effect of the pressure between the wires at least in a direction away from the forming shoe, the dewatering action being assisted by the curvature of the forming shoe due to centrifugal forces. According to the invention, the length of the active portion of the forming shoe guiding surface, the surface quality or characteristics of the guiding surface and/or the radius of curvature of the guiding surface are adjustable so that web formation and the dewatering capacity of the forming shoe are controlled. For this purpose one or more devices are coupled to the forming shoe by which the attitude and/or location thereof is adjustable.

Abstract: Operation of a multiple solids fluidized-bed black liquor combustor employing only combustion residue solids as both fine and coarse bed solids is disclosed. Under normal operating conditions, a solids distribution of fine particle sizes and coarse particle sizes with a minimal population of intermediate particle sizes is maintained. Heat and chemical values are readily recovered from the black liquor and the necessity for separation of the combustion residue salts from inert fluidized-bed solids is avoided.

Abstract: An improvement in a web-forming section of a paper machine intended as a modernization of a fourdrinier-wire part by which an improved formation of the web and an adjustable dewatering thereof by which better retention and desired distribution of fillers and fines is achieved.

Abstract: A method for delignifying ligno-cellulosic materials and efficiently separate from each other the constituents thereof. Said materials are heated in an aqueous acid medium in the presence of phenol compounds. Then the reaction medium is drained and washed for isolating the purified solid cellulose pulp, the liquid phase separating into two layers: an aqueous layer rich with pentoses and an organic layer rich with phenols and lignin, the latter providing, by distillation and pyrolysis of the residue, a quantity of phenols at least equal to that of the phenols used in the delignification stage.

Abstract: A continuous process of removing silica from spent pulping liquors (black liquors) which have been obtained by the alkaline digestion of annual plants. The spent liquor is preconcentrated and contacted with a CO.sub.2 -containing gas. The CO.sub.2 -containing gas is supplied at a rate of 30 to 40 m.sup.3 s.t.p. per m.sup.3 of spent liquor. The precipitated silica is removed from the treated liquor. The silica-containing precipitate which has been separated is diluted and washed with water and causticized by an addition of lime or milk of lime. Solid and liquid phases are separated from each other and the resulting residue is combusted.

Abstract: In order to produce a reduction in the content of suspended matter in the surplus white water in a twin-wire machine with a curved forming zone, an outer saveall for collecting white water thrown outwardly from the curved forming zone is divided up into at least two separate saveall compartments arranged after each other in the direction of travel of the wires. The white water that is caught in the separate saveall compartments is removed as separate fractions for reuse.

Abstract: A dewatering apparatus is disclosed containing a pre-dewatering funnel possessing pervious walls over which there are guided two wires. Arranged after the pre-dewatering funnel are two dewatering cylinders over which both of the wires are guided along a substantially S-shaped path of travel. A press roll is arranged after the last dewatering cylinder, this press roll coacting with further press rolls.

Abstract: The invention relates to an improvement in a method of regenerating alkaline or alkaline earth metal oxides or hydroxides from solution particularly in delignification processes wherein a suitable transition metal such as ferric oxide is burnt with the solution to produce a mixed oxide that is subsequently treated in hot water to regenerate the alkaline or alkaline earth metal oxide or hydroxide and precipitate the transition metal oxide. The improvement controls the presence of fines in the transition metal oxide to maintain these at an acceptable level in the fluidized bed combustion zone. This is achieved by contacting the fines with spent liquor from a delignification process. The invention also provides for the pelletization of the fine material of the transition metal oxide and spent delignification liquor can be used as a binder in the formation of such pellets.

Abstract: A process for removing an anthraquinone type scale comprises condensing a steam evaporated from a black liquor obtained by separating pulp from a digested mixture of lignocelluloses containing an anthraquinone type digesting assistant; and contacting a heated aqueous solution of a base in the presence or absence of a reducing agent or an alkali resistant surfactant with a wall of a condenser of an evaporator on which said anthraquinone type scale is adhered.

Abstract: In the production of multi-ply paper in a twin-wire former of the kind in which the wires define a curved forming zone, preferably a former of roll type with a smooth-faced forming roll, a substantially improved layer purity is produced in that the discharges from a first and at least succeeding portion of the curved forming zone are collected separately as different fractions. The first fraction collected nearest the multilayer headbox is returned in a first separate circuit to be used for diluting a first high consistency pulp to a first stock of headbox consistency, from which stock a first layer is to be formed directly on the outer wire in relation to the curved forming zone. At least a portion of a second fraction collected at a greater distance from the multilayer headbox is returned in a second separate circuit to be used for diluting a second high consistency pulp to a second stock of headbox consistency, from which a second layer is to be formed superimposed on the first layer.