Abstract: A cellulose pulp continuous digester (e.g. for producing kraft pulp) is operated so that it has an inverted top separator and is hydraulically filled to above the level of the inverted top separator, and may be substantially completely hydraulically full. A plurality of different liquor flows may be extracted from the inverted top separator, and an in-line drainer may be provided in a conduit through which liquid is extracted.

Abstract: A comminuted cellulosic fibrous material treatment vessel assembly includes a substantially vertical vessel having a top, bottom, and outlet, and through which the material flows in a flow direction. The vessel preferably has a substantially cylindrical wall with at least one diameter-changing transition between the inlet and the outlet. A screen assembly is preferably provided at or just past the transition. The screen assembly comprises one or more annular screen surfaces diverging in the flow direction of the material, the angle of divergence being between about 0.5-10.degree. to the vertical, and preferably substantially continuous. Providing such a screen assembly reduces the radial compression of material thereon, and increases the volume and rate of liquid that can flow through the material and be removed through the screen surface compared to a non-diverging screen surface (that is a right-cylindrical surface).

Abstract: A feeding system for feeding comminuted cellulose containing material and liquid to a continuously operating treatment vessel. The feeding system comprises a chute, operating at a first pressure, a high pressure feeder sluices the material to a second pressure, that is higher than the first pressure, for further conveyance to the treatment vessel. The high pressure feeder also receives a return liquid flow from the treatment vessel at the second pressure and recirculates a recirculation flow to the chute. The high pressure feeder is in fluid communications, regarding both the liquid and the material, with the recirculation flow when any of the pockets of the high pressure feeder is in a location which corresponds to an outlet for the recirculation flow.

Abstract: An insert is bolted to the inlet of a wood chip digester to provide air exhaust during chip loading, and over pressure relief during chip processing. The insert has an upper flange which connects to an overhead chip valve, and a lower flange which mates with the top of the digester inlet. The insert has an outer cylindrical section extending between the upper flange and the lower flange and a lower conical section which extends downwardly into the digester. An inner cylindrical sleeve is positioned coaxially with, and joined to, the outer wall by a conical ring at the top, and is joined to the conical section at the bottom. The outer wall, the conical section, and the inner cylindrical sleeve form a sealed volume, which maybe partitioned into two parts. The first part has a sector between the outer wall and the inner cylindrical sleeve which is connected to a pressure relief fitting, a portion of the sector being porous for allowing pressure relief through the fitting.

Abstract: A gas purged viewport for endpoint detection in a gas phase processing chamber is provided which prevents contamination of an optical monitoring window by use of a purge gas flow. The purge gas purges the viewport and prevents deposition of byproducts and contaminants on the window which will adversely effect endpoint detection. The gas purge viewport includes a prechamber between the optically transparent window and the process chamber. The purge gas is passed through the prechamber and into the processing chamber to purge the window. The gas purge system may also be used to purge other parts such as sensors.

Abstract: A screen used in the production of cellulose pulp mounted in a digester minimizes traditional screen problems (including clogging) without introducing new problems. The screen comprises a screen plate secured to an internal surface of the digester. The screen plate has a plurality of slots formed in it with an inclination angle, and the screen plate is positioned in the digester so that the inclination angle of the slots relative to the horizontal X axis of the X-Y plane defined by the internal surface of the digester is between 30-60.degree.. The screen plate may comprise a plurality of parallel screen bars side-by-side, or an integral metal plate with slots formed in it. The slots typically have a width between 1-5 millimeters and a spacing between them of 3-9 millimeters.

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: 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: 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: A pulp mill includes a digester which contains a raw material, a digesting medium, and a source of steam. Oxygen is injected into the steam line, at a point which minimizes exposure of the oxygen to the steam outside of the digester. The oxygen can also be injected directly into the digester. The oxygen speeds the chemical reactions in the digester, allowing the digesting process to be completed with a reduced quantity of chemicals and/or steam, and at a faster rate. The present invention improves the quality of the effluents from a pulp mill, and makes it easier for the operator of the mill to comply with environmental regulations.

Abstract: Untreated wood chips are fed to treatment, e.g. steaming at substantially atmospheric pressure, using a mechanical conveyor. Steaming may be accomplished utilizing a vertical chip bin with one dimensional convergence and side relief fed by a horizontal conveyor (e.g. screw conveyor) having a physical restriction which insures formation of a chip plug to prevent leakage of gas through the conveyor housing inlet. The physical restriction may be a generally vertical hinged plate, with an opening containing elastomeric material through which the shaft of the conveyor may pass, or a stationary generally vertical plate with one or more openings, which openings also may be covered with yielding flexible material and with the degree of sealing provided controlled by the speed of rotation of the conveyor shaft.

Abstract: A system and method for feeding comminuted cellulosic fibrous material such as wood chips to the top of a treatment vessel such as a continuous digester provide enhanced simplicity, operability, and maintainability by eliminating the high pressure transfer device conventionally used in the prior art. Instead of a high pressure transfer device the steamed and slurried chips are pressurized using one or more slurry pumps located at least thirty feet below the top of the treatment vessel and for pressurizing the slurry to a pressure of at least about 10 bar gauge. A return line from the top of the digester may, but need not necessarily, be operatively connected to the one or more pumps and if connected to the pumps the pressure in the return line may be reduced utilizing a pressure reduction valve and/or a flash tank. Steam from the flash tank may be used in steaming the chips.

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: Low temperature steaming and slurrying of wood chips results in significant improvement in treatment, the chips being maintained at a temperature below 110.degree. C. (more desirably at about 105.degree. C. or less, and most desirably at about 100.degree. C. or less) until actually heated to cooking temperature. Steaming may be accomplished utilizing a vertical chip bin with one dimensional convergence and side relief or a horizontal steaming vessel, the steaming device connected to a high pressure feeder. A pump having an NPSHR less than the NPSHA may be used for drawing slurry into the high pressure feeder from the steaming device, or a pump may be disposed between the steaming device and the high pressure feeder for forcing slurry into the high pressure feeder through a conduit including a radiused elbow. The steaming is practiced at a pressure of 5 psig or less, preferably substantially atmospheric steaming is practiced.

Abstract: A novel method and device for the production of pulp by a continuous cooking process is provided wherein hot impregnated chips are fed into the top of a countercurrent steam digester which has a bottom outlet and at least one draw off screen girdle for removing black liquor. At least 50%, preferably 70%, of the cooking liquor is fed to the top of the digester as finely divided droplets.

Abstract: Provided is a method and apparatus which decreases a liquor--to--wood ratio at the top of a continuous digester while increasing a liquor--to--wood ratio in the upstream pre-impregnation vessel. A substantially wood-chip free liquor portion is drawn from the top of the digester through a heater to the bottom of the pre-impregnation vessel through a return conduit. A stream is drawn off the return conduit, upstream of the heater, for transfer to the top of the vessel without mixing with wool chips.

Abstract: The pretreatment of cellulosic fibrous material is adjusted to improve pulp strength. The cellulosic material is initially pretreated with a low temperature alkaline liquid (e.g. 80.degree.-110.degree. C.), and then with a higher temperature (but still below cooking temperature), higher alkali concentration liquor. Only then is the material--which has alkali which has completely penetrated the cellulose fiber walls--subjected to cooking with white liquor at a temperature of about 150.degree.-180.degree. C. Green, white, or black liquor can be used in the first impregnation zone, while white liquor (with polysulfide addition) is preferably used in the second zone.

Abstract: A screen system for a digester for continuous cooking under raised pressure and temperature of fibre material in a vertical vessel, where input of fibre material and cooking liquid takes place at the top of the digester, withdrawal of spent cooking liquor is carried out from at least one digester screening arrangement (1D) between the top and the bottom of the digester, and fibre material is fed out from the bottom (1C) of the digester, wherein at least one of said screening arrangements (1, 2) has at least one screen element (2A) of which the main configuration is circular and which is assembled by means of welding, and which is fitted into the digester shell by means of welding.

Abstract: A method of rehabilitating a wood pulp digester, comprising applying to an interior surface of the digester wall a tacky silicone rubber layer, and then applying vertical strips of metallic sheet material to form a composition layer of said silicone rubber and said metal strips.

Abstract: A method and apparatus for the continuous production of cellulosic pulp for use in a papermaking process. The apparatus includes a vessel containing a pulping liquor and the vessel consists of a first impregnation zone and a second attrition zone. Wood chips are continuously fed into the upper end of the first zone and are subject to gentle agitation to impregnate the chips with the liquor. The impregnated chips then flow into the second zone where they are heated to a low temperature of 80.degree. to 120.degree. C. and subjected to more severe agitation to break down the chips and liberate the individual fibers. The liquid level in the first zone is higher than in the second zone, causing the liquid to flow upwardly in the second zone with the cooking liquor and the liberated fibers being continuously discharged from the upper end of the second zone, while larger wood chips are retained in the second zone for further attrition.

Abstract: In a pulp digester for continuous cooking under raised pressure and temperature of fiber material in a vertical digester (1), input of fiber material and cooking liquid takes place at the top of the digester, withdrawal of spent cooking liquor is carried out from at least one digester screening arrangement (1D) between the top and the bottom of the digester, and fiber material is fed out from the bottom (1C) of the digester, and at least one screening arrangement (2) in the lower half of the digester, wherein at least one of said screening arrangements (1, 2) has at least one screen element (2A) of which the main configuration is of angular shape, preferably rectangular, most preferred square, having a screen face (3A) of which the total area is less than 1 m.sup.

Abstract: A reactor system is disclosed for the treatment of cellulosic pulp in which pulp is distributed upward through a vertical reactor using a unique conical distributor and is discharged using a unique dilution method to eliminate plugging. The system is particularly useful for delignifying virgin wood pulps or decolorizing pulps made from waste paper materials.

Abstract: An apparatus and method for treating cellulosic wood chips in a digestion process for the liberation of pulp in a caustic hydroxide solution at high pressures and temperatures by delivering preconditioned wood chips to a first chamber and circulating a low temperature black liquor through the chamber to preheat the chips, while continuously feeding the chips through the chamber to a second chamber at high temperature and pressure, circulating high temperature black liquor to the chips in the second chamber to advance them to cooking temperature, feeding white liquor and the chips to a digester for the digestion process over a predetermined period of time, and removing digested pulp and delivering the pulp to a washer with the black liquor for washing being utilized for the first chamber, and heating the white liquor through a heat exchange process with the high temperature black liquor.

Abstract: In the continuous cooking of comminuted cellulosic fibrous material (e.g. wood chips) to produce paper pulp, the material passes upwardly in an impregnation vessel which is within and concentric with a continuous digester and open at the top to digester pressure. At the top of the impregnation vessel, a solids/liquid separator (a screw within a screen cylinder) is provided. Separated liquid is returned in a conduit adjacent the exterior of the impregnation vessel, and open at the top to digester pressure, and passes out the bottom of the digester. The impregnation vessel is welded to the bottom of the digester, and the bottom of the digester is generally hemi-spherical, and substantially devoid of packings.

Abstract: A continuous, upright, digester for paper pulp is utilized as a structural support for accessory vessels, such as a chip bin and flash tanks. Generally horizontal steel beams are connected to the digester and extend outwardly from opposite sides of the digester vessel. One set of beams is connected to the impregnation vessel, and supports the chip bin on them. A steaming vessel may be mounted on a horizontal platform below the chip bin. On the opposite side of the digester, the second horizontal beams extend to a pair of vertical legs spaced apart approximately the diameter of the digester. First and second flash tanks, one above the other, are supported by the second set of horizontal beams, and a third set below the second set, those beams--and structures connected to them--being the only support for the flash tanks.

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: A cellulose pulp slurry is delignified in an apparatus comprising a vertical cylindrical barrel chamber, a cone-shaped bottom chamber connected to the barrel chamber and having a circular inlet formed in a lower end portion thereof, and a cone-shaped top chamber connected to the barrel chamber and having a circular outlet formed in a top end portion thereof, in which apparatus the cone-shaped top and bottom chambers converge at a convergence angle of 60 degrees or less respectively, by feeding a cellulose pulp slurry containing an alkali and oxygen and having a pulp consistency of 8 to 15% into the apparatus through the circular inlet of the bottom chamber at 70.degree. C. to 140.degree. C., and discharging the pulp slurry through the circular outlet of the top chamber, while controlling the flow speed of the pulp slurry in the barrel chamber to a level of 0.4 m/min or more.

Abstract: Extended delignification of kraft pulp in a pressure diffuser allows a pulp mill with a digester (e.g. continuous digester) to increase its production capacity without building a new line, or to decrease its demand in its bleach plant, or to increase the strength of softwood pulp it produces. Comminuted cellulosic fibrous material is kraft cooked to produce kraft pulp having a blow temperature over about 300.degree. F. The pulp is diffusion treated in the first stage of a pressure diffuser to replace the water around the pulp with delignifying liquor. The liquor has a dissolved lignin concentration of less than 12% (optimally less than about 4%), has an effective alkali concentration of at least 2 gm/l (preferably 8-55 gm/l), and a temperature of at least about 300.degree. F. Treating the pulp with the delignifying liquor significantly reduces the K-number (e.g. on the order of about 5). After extended delignification, the pulp is washed in subsequent stages of the pressure diffuser.

Abstract: A method and apparatus for continuous fiber material treatment of a fiber column without compaction of the column. A liquid layer is disposed between upper and lower treatment zones (i.e. between a cook and wash zone), and apparatus is provided for interrupting the fiber column of the upper zone. The apparatus may include a conical table which generally supports the fiber column of the upper zone yet allows passage of fiber material from the upper zone to the lower zone to allow formation of another fiber column in the lower zone. The liquid layer area may be of the same or smaller cross-sectional area than the upper zone, and the lower zone may be horizontally offset from the upper zone if desired.

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 used in the pretreatment of wood chips in a process for converting biomass to a liquid hydrocarbonaceous fuel. The apparatus functions to break down the wood chips to a size distribution that can be readily handled in a slurry form. Low maintenance operation is obtained by hydrolyzing the chips in a pressure vessel having no moving parts.

Abstract: Cellulosic material, such as wood chips, is fed from a storage bin (10) through a compacting screw feeder (12) to an impregnation chamber (16) in housing (14) wherein the material is contacted with a treatment liquid. The impregnated chips and treatment liquid are passed from chamber (16) by a triple flight intermeshing screw feeder (18) directly to the interior of an inclined treatment vessel (20) wherein the material is digested by cooking at elevated temperature and pressure in both the treatment liquid and a treatment vapor.

Abstract: A method and apparatus for continuously treating cellulosic chips to prevent degredation of the chips as a result of mechanical action exerted on the chips by a scraper. A false bottom is provided in a vessel with the scraper mounted for rotation about a vertical axis just above the false bottom, a large central opening being provided in the false bottom. The scraper removes chips from the vessel through the false bottom opening to a bottom portion of the vessel. The temperature within the vessel at the area of the scraper is maintained at a first temperature that is low enough so that loss of strength of the chips material does not result from mechanical action exerted on the chips by the scraper. Liquid is introduced into the vessel bottom portion at a second temperature that is approximately at the cooking temperature for effecting digestion of the chips, and substantially higher than the first temperature.

Abstract: A method and apparatus provide for the continuous treatment of a porous, fibrous material such as paper pulp, with a gas, such as ozone. The material is entrained with gas and passed in a first path. The material and gas move in a path defined by a downwardly curved upper wall and an open bottom, with a baffle disposed adjacent the bottom termination of the downwardly curved wall, so that the material is separated from the gas, the material flowing in a second path and the gas in a third path, distinct from the second path. The material in the second path is moved so that it intersects the flow of gas in the third path at least once, with the gas passing through the material while remaining in the third path, until the desired treatment of the material has been achieved. Preferably the second path is a serpentine path including horizontal portions, and the third path is a substantially straight downward path. After treatment, the material is discharged in a fourth path, and the gas passes along a fifth path.

Abstract: Waste paper is chemically and mechanically treated to pulp it into a stock. The waste paper is tumbled, without mechanical beating and without rotary means likely to become fouled by foreign material mixed with the paper. A chemical pulping liquid is mixed with the paper as it is being tumbled. The resulting tumbled, pulped waste paper is delivered to a reaction tower where it is further chemically pulped. The waste paper is removed from the bottom of the reaction tower. Various embodiments of paper tumbling devices are disclosed including a rotating drum, stepped conveyor belts, stepped rollers, a vibratory conveyor and a tumbling tower with baffle plates along its length. The reaction tower has an adjustable sized outlet opening at its bottom. An appropriate conveyor is insertable through the outlet opening of the reaction tower for extracting pulped paper stock.

Abstract: There is disclosed a process for the transfer of fiber material from one circuit of circulating liquid to another, where the fiber material is transported by circuits positioned at right angles to the axis of rotation of a rotary transfer or feed valve and the circulating, transporting liquids are screened off through self-cleaning screens. The transfer valve contains a pocket and three working positions, a filling circuit, an emptying circuit, and an intermediate position for preheating the fiber material or providing a temperature lock depending upon the rotation of the pocket.

Abstract: In a reactor plant for treating finely divided bulk material an acid bulk material or pulp having a solids content of approximately 35-50% is conveyed to a combined high-consistency ozonizer and maturation reactor as a substantially vertical pulp column forming a gas blocking means. In the transition area between the ozonizer and the maturation reactor the finely divided and ozonized pulp which has a very acid pH-value is mixed with chemicals to a pH-value of approximately 8-11 and to a solids content of approximately 15-20%, at which solids content the alkaline pulp in the form of a continuously advancing column is subjected to a maturation process which terminates at a pH-value of the pulp of 6-7.

Abstract: A process for producing alkali pulp by using a single, cylindrical pressurized reaction vessel having therein a liquor-inpregnating zone, a cooking zone, a washing zone, and a diluting zone in that order, and having a motor-driven scraping or agitating device and a pulp discharging outlet in the end portion of the diluting zone. Alkaline aqueous medium containing dissolved oxygen therein is introduced into the diluting zone. A part of the introduced alkaline aqueous medium countercurrently contacts cooked cellulosic materials transferred from the washing zone to the diluting zone to proceed with oxygen-alkali delignification, and is finally discharged out of the vessel from the end portion of the cooking zone.

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

Abstract: 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: The continuous treatment of a cellulosic material in the form of chips to produce at least partial delignification of the material without true mechanical grinding is effected in apparatus comprising two parallel meshing screws which are rotated in the same direction in a sheath and have identical threads providing a plurality of zones of different pitch. The material is passed in succession through a first zone for feeding the material downstream, a first braking zone for causing a first compression of the material, a second zone for feeding the material downstream and in which the material is brought into contact with a reagent, e.g. steam or a chemical reagent, and a second braking zone for causing a second compression of the material.

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: In an apparatus for treating cellulose pulp with oxygen gas by passing the pulp and oxygen gas through a reaction vessel at elevated temperature and pressure, the improvement whereby the exothermic heat of reaction is controlled and the temperature of the pulp being treated is maintained below the point where the pulp would be degraded, the improvement comprising means for withdrawing oxygen gas from the vessel after the gas has been in contact with the pulp, dividing the withdrawn gas into two portions, cooling one of the portions to remove water vapor therefrom, recombining the gas portions whereby the resulting gas has a lower temperature than the gas withdrawn from the vessel and returning the resulting gas to the vessel for further contact with pulp therein, the amount of gas withdrawn from the vessel and the degree of cooling of the cooled portion of withdrawn gas being regulated to maintain the temperature within the vessel below the point where the pulp is degraded.

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: A method and apparatus for continuous oxygen bleaching of cellulosic pulp is provided utilizing first and second pressurized chambers with a number of tubes in fluid communication with both of first and second chambers. Oxygen bearing fluid is intimately mixed with digested cellulosic pulp and is continuously fed under pressure to the first chamber. Communication is selectively provided between the first and second chambers through at least one of the tubular members to allow passage of pulp from the member to the second chamber. The tubular member through which pulp flows to the second chamber is progressively changed as are the members through which passage is blocked, so that the pulp remains within each tubular member sufficient time to allow oxygen-bleaching thereof without degradation, and passes through the members without channelling. The oxygen bleached pulp is continuously discharged from the second chamber. The passage of pulp through the tubular members may either be downwardly or upwardly.

Abstract: A process and apparatus for automatically maintaining the moisture content in a continuously conveyed batch of porous materials is described. The porous material is continuously fed through a treatment tank, wherein it is contacted with a liquid to be absorbed therein. The moisture content of the material is continuously monitored as a direct function of the combined weight of the material and the treatment tank to generate correction signals. The correction signals are utilized to vary the dwell times (up or down) of the porous material in the treatment tank. By varying the dwell times the porous material is contacted by the treating liquid for either larger or shorter periods until the weight of the tank and material therein returns to the weight desired. Thus, the moisture content of the porous material is continuously adjusted to a substantially constant value.

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

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

Abstract: An apparatus and method for the digestion of cellulosic fiber material providing pulp of very uniform quality. Cellulosic fiber material entrained in treatment liquid is fed into a top portion of a first vertical treatment vessel, impregnation of the fiber material with treatment liquid taking place in the first vessel. A first flow path of fiber material entrained in and impregnated with treatment liquid is established from the bottom of the first vessel to a top portion of a separate second vertical treatment vessel, liquid substantially filling the second vessel. Liquid is withdrawn from the top portion of the second vessel (without screening) and a second flow path is established of the liquid withdrawn from the second vessel back toward the bottom portion of the first vessel, heating of the liquid during transport in the second flow path taking place.