Abstract: A feeding arrangement comprising a transportation means (3) for transportation of material from a material supply to at least a first chute (7) and a second chute (8), a plug screw feeder (11) for feeding the material to the treatment stage. The plug screw feeder (11) is provided with a first inlet opening (12) connected to the first chute (7), which first chute (7) is provided between the transportation means (3) and the plug screw feeder (11). Further, the transportation means (3) comprises at least selectively openable first and second outlets (4, 5) arranged at different axial positions along the transportation means (2), which first outlet (4) is in connection with the first chute (7) and the second outlet (5) is in connection with the second chute (8).

Abstract: Digestion units for processing cellulosic biomass can comprise a chamber having a height that is greater than its width, the chamber having an opening suitable for solids introduction located within the upper 20% of its height; one or more first fluid conduits connected to the chamber within the lower 20% of its height, at least one of the first fluid conduits extending into the chamber and being elevated above the bottom of the chamber; one or more second fluid conduits connected to the chamber within the upper 20% of its height, at least one of the first fluid conduits being fluidly coupled to at least one of the second fluid conduits; a porous medium located in the chamber within the lower 20% of its height; and a movable pressure isolation device covering the opening; wherein the digestion unit is operable to maintain a pressure of at least about 30 bar.

Abstract: The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel. The outlets of the pumps are combined at a merging point before a common transfer line extends to the top of the digester. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced.

Abstract: The device is for the dilution of dewatered cellulose pulp that maintains a consistency of 20-30% or greater. By shredding of the pulp to a finely divided dry-granulate, dilution to a homogeneous consistency in the medium consistency range can take place exclusively through hydrodynamic effects from the addition of dilution fluid. The dilution fluid is added to granulate at a position at which granulate is in free fall in a standpipe and above a level Liqlev of diluted pulp in the standpipe. A number of nozzles are arranged around the periphery of the stand pipe, directed in towards the center of the stand pipe, obliquely downwards in the direction of fall of the granulate. It is possible through this simplified procedure to avoid completely the conventional dilution screws, and this reduces the investment costs and operating costs, while at the same time unnecessary mechanical influence of the pulp fibers can be avoided.

Abstract: A chemical pulp mill system and method of using black liquor flashing steam from a digester system comprises generating black liquor in the digester system, sending the black liquor to an evaporator system without using any pre-evaporator system, flashing the black liquor in the evaporator system to yield steam, and using at least some of the steam for chip steaming in a chip bin and/or for supplying in-direct heat exchangers in the digester system for pre-heating white liquor and/or filtrates for use in the digester system.

Abstract: A method for the impregnation of untreated chips during the manufacture of chemical pulp. The untreated chips are fed without preceding steam treatment into an impregnation vessel that has an upper part with a first area (A1) and a lower part with a second area (A2) that is larger than the first area (A1) by a factor of at least ?{square root over (2)}. The chips establish in the upper part a level of chips that is located at a level (h) above a level of fluid consisting of liquor. The chips after passage of the upper part pass through a transitional part, where an increase in area from the first area (A1) to the second area (A2) takes place, and it is here that the angle of repose of the chips is reduced.

Abstract: A method for producing paper pulp from a lignocellulosie vegetable raw material. The method includes contacting the raw material with a mixture of formic acid and acetic acid (in an amount more than 5 wt. % of the mixture) at a temperature and for a suitable reaction time, the whole being performed at room temperature. The paper pulp is separated from the organic phase and optionally bleached with ozone. The organic phase is treated to enable the recycling of the formic and acetic acids and the extraction of lignins, sugars and excess acetic acid.

Abstract: An apparatus for carboxylating wood pulp which utilizes the wood pulp bleach plant and the method of carboxylating the pulp which takes place in the bleach plant.

Abstract: For a process and an apparatus for loading fibers contained in a pulp suspension with calcium carbonate, a calcium oxide and/or a medium containing calcium hydroxide is fed to the pulp suspension, and the so treated pulp suspension is further charged in several reactors with pure carbon dioxide or a medium containing carbon dioxide. The reactors can be connected in series and/or in parallel.

Abstract: A continuous, alkaline process for the production of pulp from wood chips, wherein the preheated chips are subjected to an extended impregnation step for at least 60 min, preferably longer, at a temperature not exceeding the impregnation liquor boiling point at atmospheric conditions, and a rapid heating and cooking period of less than 65 min, preferably shorter, followed by cooling to below reaction temperature. Fresh alkali is added both during impregnation and the heating/cooking period.

Abstract: For a process and an apparatus for loading fibers contained in a pulp suspension with calcium carbonate, a calcium oxide and/or a medium containing calcium hydroxide is fed to the pulp suspension, and the so treated pulp suspension is further charged in several reactors with pure carbon dioxide or a medium containing carbon dioxide. The reactors can be connected in series and/or in parallel. The reactor can produce different forms of calcium carbonate.

Abstract: A pre-treatment device for wood chips for pulping comprises a tube through which the wood chips fall into a digester. Steam is injected into the tube through rings of nozzles, which are angled circumferentially to impart a rotary and turbulent motion to the falling chips. Some nozzles are angled downwardly to encourage the chips to flow freely through the tube, some are horizontal to encourage a longer dwell time near the nozzles. Digesting liquor is also sprayed onto the chips from spray nozzles after the first ring of steam nozzles. The heat and steam expel air and other non-condensable gases and volatiles from the chips, allowing them to absorb the liquor. At the bottom of the tube, the chips are propelled down and outwards by jets of higher-pressure steam, spreading and packing them into the digester.

Abstract: A continuous digester configuration and process for continuously cooking and digesting cellulosic material and producing cellulosic pulp is disclosed. The digester configuration comprises a plurality of jump-stage recirculations located along the length of a continuous digester vessel, wherein each of the jump-stage recirculations moves extracted liquor from one elevation of the digester vessel and re-introduces the liquor at a higher elevation in the vessel to maintain an internal liquor downflow substantially throughout the entire digester vessel. The process for continuously cooking and digesting cellulosic material comprises maintaining an internal concurrent liquor downflow substantially throughout the continuous digester vessel, wherein the internal liquor downflow does not exceed 400 gallons per ton of b.d. wood feed.

Abstract: The invention relates to a system and a process for the oxygen delignification of pulp consisting of a lignocellulose-containing material that has a mean concentration of 8-18% pulp consistency. The oxygen delignification takes place in a first stage with a short dwell time of about 3-6 minutes, at a low temperature of about 85° C. and under a low pressure of approximately 0-4 bar. A concluding stage has a longer dwell time of about 50-90 minutes, at a higher temperature of approximately 100° C. and under a higher pressure of about 8-10 bar.

Abstract: Apparatus for the production of cellulose paper pulps from vegetative masses, comprising: a tower for sterilizing the mass to form a culture medium; a first screw for mixing the sterilized mass with an inoculum and handling the same in a sterile environment; a first conditioning and reaction chamber for mixing and handling the inoculated mass in a sterile environment and controlled atmosphere of CO2 and O2, with controlled temperature and pH; a hydraulic pulper for the elementarization of the mass and its soaking up with suspensions of enzyme mixes; a hammer mill for the elementarization of vegetative material, to break up knots of stems and to pulverize leaves, detach bast from wood; a rotating tumbler having reels and counter reels for separating various fractions; a rotor compactor to reduce the volume of the vegetable mass and to remove air contained in the same; a second screw for mixing the compacted vegetetative mass with extracts containing enzymes and with water for handling in a sterile environment;

Abstract: A pulper in a stock preparation system includes a housing with a fiber inlet, at least one water inlet, at least one outlet and an inner chamber. A plurality of stationary pulping foils are attached to the housing and extend into the inner chamber. A rotatable shaft assembly extends through the inner chamber. The shaft assembly includes a shaft, an auger positioned around the shaft and relative to the fiber inlet and a plurality of movable pulping foils carried by and extending from the shaft. A conical valve is positioned in association with the outlet and is selectively movable to open and close the outlet.

Abstract: There is a process for making a cellulose ether. The process comprises the following: a) alkalyzing a cellulose pulp; b) etherifying the alkalyzed cellulose pulp to form a cellulose ether; c) washing the cellulose ether; d) drying the cellulose ether; e) milling the cellulose ether to a particulate form; f) heating the particulate cellulose ether; g) tumbling the particulate cellulose ether while simultaneously contacting it with an acid to partially depolymerize it to a lower molecular weight; h) partially or substantially neutralizing the acid. There is also an apparatus for making the cellulose ether.

Abstract: A cellulose pulp continuous digester (e.g. for producing kraft pulp) is operated so that it has the advantages of a hydraulic digester yet has a gas-filled zone over the liquid level. A slurry of chips and cooking liquor is introduced into the top of the digester vessel through an inverted top separator. A liquid level is established below the inverted top separator, and a chips level is established below the inverted top separator (above or below the liquid level). A gas-filled zone above the liquid level includes compressed gas, and is at a temperature of less than 160 (preferably less than 120).degree. C. and at a pressure of between 50-200 (preferably 80-150) psig. The digester may have a first diameter portion (about 3-5 meters) at the top and a second diameter portion (at least about seven meters) below the top, with the inverted separator in the first diameter portion, the liquid level in the first diameter portion, and the chips level in the second diameter portion.

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

Abstract: A 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 number of distinct parallel digesters are fed with chips from a common steaming vessel. After steaming the chips are slurried and pressurized, and substantially simultaneously the steamed, slurried, and pressurized chips are transferred to at least some of (and typically each of) the distinct parallel digesters. A material stream is split into a number of individually controllable material streams (one for each of the digesters) either at the discharge from the steaming vessel, after slurrying (or at the discharge from a slurrying vessel), or after pressurizing (e.g. in a high pressure transfer device). For example a multi-branch conduit may be connected to the slurry outlet from the high pressure transfer device, the conduit having a branch directly connected to each of the digesters. A distinct return conduit may also be provided from each of the digesters to the high pressure transfer device, each return conduit preferably has a distinct flow control device and/or pump which are individually controlled.

Abstract: System for feeding a suspension, preferably a suspension of chips in a liquid carrier, to a pressurized vessel in a cellulose pulp mill, which system comprises at least one pump (25, 26) between a low-pressure part and the pressurized vessel for driving the suspension from the low-pressure part into the vessel, which pump is of the type which comprises a number of parallel discs (40, 42) which are held together to form a stack (39) and rotate in a pump chamber (36) in a pump housing about a common axis of rotation, with the spaces (46) between the discs being greater than the particles in the suspension, and with an axial inlet and a tangential outlet for the suspension. The invention also includes a pump and an apparatus unit which are intended to form part of the system.

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

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

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

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

Abstract: A two stage sulfonation system includes a mixing tank, a retention tank, a thickening press, a pressurized vessel, and a liquor recovery press in series relation. A sodium sulfite generation unit is connected to maintain a supply of sodium sulfite solution in a holding tank from which a controlled quantity of said solution is metered and injected in the mixing tank. Liquor extracted in the thickening press is cycled back to the mixing tank. Liquor extracted in the recovery press is moved to an intermediate tank and then transferred to the sodium sulfite generation unit, there fortified with fresh sodium sulfite and forwarded to the holding tank to maintain therein an appropriate supply to service the system. The system is designed to receive mechanical pulp, in a slurry form, first introduced into the mixing tank simultaneously with a metered charge of sodium sulfite solution from the holding tank, the sodium sulfite content of which is at a level from about 40 to about 200 g/l.

Abstract: An apparatus and method for use in a batch digesting process to quantitatively displace fluids in the digester by pumping into the digester under pressure a first volume of displacing fluid at the upper end and a second volume of displacing fluid at the lower end of the digester. Displaced fluids are collected and removed from the digester near the midline between the top and the bottom of the digester.

Abstract: A method and apparatus provide for the continuous digestion of comminuted cellulosic fibrous material (e.g. wood chips) to produce paper pulp, with increased sulfidity. When black liquor is withdrawn from the continuous digester, instead of merely passing it to a pair of flash tanks and then to recovery, the concentrated liquor from a first flash tank is fed to a vessel in which the comminuted material is slurried with a liquid. Since the black liquor remains in intimate contact with the chips for a significant period of time, the lignin in the chips is partly sulfonized. Ultimately the black liquor is replaced with white liquor or the like, and the separated out black liquor is circulated to recovery or disposal. A high pressure feeder and a solids/liquid separator are utilized.

Abstract: Bamboo can be formed into a suitable pulp if prior to digestion it undergoes a process of shredding, washing and wet depithing. The fibers are then chemically digested preferably by a process which uses rapid pressure drops to open the fibers using the energy contained in the wet superheated fibers.

Abstract: A method for producing mechanical pulps which are useful for producing coated light weight paper, magazine paper and the like, is disclosed, which includes preheating lignocellulose-containing material in the presence of impregnation chemicals, refining the preheated lignocellulose-containing material utiilizing a pair of counter-rotating refining discs under pressure, bleaching the thus produced partially refined lignocellulose-containing material, and refining the bleached material in a second refining step utilizing a pair of refining discs, one of which is stationary and the other which is rotating under pressure.

Abstract: Apparatus for reacting lignocellulosic material with a gas phase comprising a nitrogen oxide and oxygen under controlled gas pressure in the presence of water, for example, as a pretreatment before an alkaline delignification, comprising in combination:(1) a first reaction chamber receiving water-containing lignocellulosic material, nitrogen oxide, and optionally oxygen containing gas;(2) a first inlet for introducing lignocellulosic material into the first reaction chamber;(3) a second inlet with control means for introducing nitrogen oxide into the first reaction chamber;(4) a first outlet for withdrawing lignocellulosic material after reaction with oxide from the first reaction chamber;(5) gas locks retaining gas pressure in the first reaction chamber at each of the first inlet outlet;(6) a second reaction chamber in connection with the first reaction chamber via the gas lock at the outlet thereof and receiving lignocellulosic material after reaction with nitrogen oxide;(7) a third inlet with control means

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

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

Abstract: A 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: Lignocellulose is pulped batchwise by introducing it and the white liquor in predetermined quantity, together with a variable quantity of black liquor, into a continuously steam pressurized digester. When the cooking cycle has been completed, the pulp product is withdrawn. The time intervals of feed material introduction and pulp product withdrawal are correlated to insure that all of the lignocellulose charged to the digester is cooked uniformly, as by withdrawing the pulp product over a time interval which is substantially equal to the feed time. For economy and efficiency of operation, the digester preferably is operated in conjunction with one or more companion digesters to which it is connected. The first digester then is blown while a second digester is charged, making possible transfer of hot pressurized black liquor from the former to the latter.

Abstract: A direct-steamed laboratory minidigester and a method of operating it are disclosed. This unit may be used to predict process parameters, e.g., yield and Kappa number, for operation of commercial direct-steamed digesters. Runs may be made rapidly and with small quantities of wood and chemicals. A plurality of units may be operated in parallel to generate replicate data points for statistical analyses or operated simultaneously, each under different conditions, to screen process variables, e.g., chemical charge, wood furnish, pressure, temperature, steam rate, and cooking time.

Abstract: Process and apparatus are provided for the preparation of improved high-yield cellulose pulps, such as semichemical, chemimechanical, thermomechanical, and mechanical pulps, which comprises mechanically defibrating a mixture of particulate lignocellulosic materials which have been partially pulped and softened to different extents. Part of the raw lignocellulosic material is particulate form is washed, moistened with steam, impregnated with pulping chemicals and pulped to a yield of from about 65 to about 92%. Another part is treated in similar manner but either not pulped at all or, if pulped, pulped to a lesser extent. The two parts are mixed without intermediate washing, after which the mixture is subjected to a vapor phase pulping by heating to a temperature within the range from about 90 to about 200.degree. C. under pressure to obtain softening of the lignin, and delignification, after which the resulting product is mechanically defibrated to form cellulose pulp.

Abstract: A method and apparatus for treating cooked fiber pulp as it comes from a continuous digester. The cooked pulp is bleached by intensively mixing the pulp with an oxygen containing gas, reacting the mixture while moving the mixed mass upwardly through a funnel shaped body within a pressurized reactor. The funnel shaped body is open at the upper end whereat the pulp mixture cascades over the side and flows downwardly into a ring chamber area between the reactor shell and funnel body, the pulp thereby forming a pressure barrier to any surplus gas within the reactor. The surplus unreacted gas is removed from the upper portion of the chamber for recycle with fresh pulp from the digestor and added gas. The treated pulp is removed from the lower portion of the ring chamber after passing downward therein.

Abstract: A method for continuous treatment of fiber material in a digestor or the like that allows substantial segregation of the digestor treatment zones so as to prevent upflow of liquid from a bottom zone to an upper zone. An area of reduced cross-sectional area is provided between each treatment zone which increases the velocity of flow of fiber material and entrained liquid in that area, and substantially prevents upward movement of liquid therepast.

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