US3258390A - Method and apparatus for maintaining a water balance during impregnation and digestion of cellulosic material - Google Patents

Method and apparatus for maintaining a water balance during impregnation and digestion of cellulosic material Download PDF

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US3258390A
US3258390A US316021A US31602163A US3258390A US 3258390 A US3258390 A US 3258390A US 316021 A US316021 A US 316021A US 31602163 A US31602163 A US 31602163A US 3258390 A US3258390 A US 3258390A
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liquor
impregnation
tube
chips
steam
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Ii George H Tomlinson
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Domtar Inc
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Domtar Inc
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/22—Other features of pulping processes
    • D21C3/24—Continuous processes
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C1/00—Pretreatment of the finely-divided materials before digesting
    • D21C1/10—Physical methods for facilitating impregnation

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  • pulp has been commercially produced by submerging the chips in an excess of digestion liquor and using this excess liquor, which may be circulated throughout the chip mass, as a heat exchange medium. For instance, steam may be admitted to a zone near the bottom of the digester and the liquor so heated circulated by convection .to heat the chips. Alternatively, the liquor may be circulated by means of a pump through a heat exchanger external to the digester, and then return to the digester.
  • the main object of the invention is to provide an improved system of maintaining a proper water balance in the material digested.
  • the system of impregnation which is one of the main lfeatures of this invention includes a simultaneous evaporation of water to maintain such ratio of liquor to wood, that there will be no excess liquor over that required to completely impregnate the chips, this ratio being accurately and readily maintained in spite of variations in moisture content of the entering chips, liquor, etc.
  • Patented June 28, 1966 A further object is to provide an improved system "of impregnating, cooking, Washing and evaporating.
  • Another feature of this invention is the economy in chemical requirements as less chemical is required in the system to properly impregnate the chips.
  • Another object is to provide a system with greater overall heat economy.
  • a substantial percentage of residual heat from this combined impregnating, cooking, washing and evaporating system is in the form of steam which can be used for other purposes. This may be contrasted with lower temperature vapour and liquor available from the batch operation. In addition, a reduction in the total heat exchange area is possible. Furthermore a high percentage of secondary heat from the system can be recovered in the form of hot water.
  • a further object of the invention is an improved washing system which allows a higher black liquor concentration at elevated temperature from the washing system.
  • Another feature of the instant system is the condensate recovery from which sufiicient water is available to supply all the demands of the washer, together with some of the water required in the black liquor recovery system.
  • FIG. 1 is a schematic illustration of one embodiment of the system.
  • FIG. 2 shows a system using a digester having an impregnation zone and a digestion zone and wherein liquor is flashed externally of the digester.
  • FIG. 3 schematically illustrates an alternative type of washer system.
  • Chips -fe'd form the chip storage bin '10 are first subjected to presteaming in the presteamer lal and then pass through a rotary valve 12 into an impregnation tube 13 partially [filled with liquor. Within the tube 13 the chips are impregnated at controlled pressure temperature, liquor concentration and time. The impregnated chips, free of residual liquor, then discharge through another rotary valve 14 to the cooking tube 15 where the chips are brought to temperature by means of direct steam through steam line 16 and the cooking cycle is carried-out at controlled temperature and time. As the cooking proceeds during passage through the tube 15 the chips shrink and black liquor is discharged from them; this discharged black liquor is removed from the coking tube 15 through the line 32.
  • the chips From the cooking tube the chips pass through a third rotaryvalve 18 to tube :19 where they are carried by a screw conveyor 20, in the tube 119 a major portion of the heat is removed from the digested chips and the chips are partially washed by counter current contact with wash water from a further stage such as press washer 2&1. Washer 21 provides a second stage of washing of the washer system. The digested and washed pulp is recovered at high consistency through line 22.
  • This control is accomplished with the instant invention by superheating the re-circulating liquor a few degrees higher than the temperature maintained in the impregnation tube and allowing the liquor to flash either in the head of the tube or in a separate flash tank at some point after heating and before returning to the digester.
  • product process steam at approximately 15 to 75 p.s.i.g. corresponding to a temperature in the tube of 120160 C. is thus available for further use.
  • This impreg nator consists of a cylindrical impregnator tube 13 set at an angle to the horizontal and provided with a central midfeather dividing the tube in two sections.
  • the angle of this tube is usually approximately 45 from the horizontal, but this angle may be varied within certain limits (approximately 30 to 60 to the horizontal).
  • Chips are carried within the impregnator tube 13 by a controlled slow speed flight type conveyor or the like schematically indicated at 24 and are moved downward on the 'upper side of the midfeather 23 and upward along the lower side of said midfeat'her.
  • Liquor is circulated through the impregnator tube '13, via line 25 to a heat exchanger 26 and back to the top of the tube 113, through line (29.
  • the heat exchanger is heated by high pressure steam from steam line 27.
  • make-up liquor is added from line 28, and the now fortified liquor is heated in heat exchanger 26 and recirculated through line 29 to the impregnation tube 13 which is held at a predetermined pressure by a pressure control .valve 30 in line 30.
  • This fortified liquor heated to a predetermined temperature higher than the equilibrium temperature corresponding to the impregnation tube pressure enters, through line 29, the top of tube 13' above the level of the liquid therein and a portion thereof is flashed to steam. Steam thus produced is discharge-d at a predetermined pressure through the pipe 30.
  • impregnated chips are carried by conveyor 24 to a point above the liquid level within the impregnation tube 13 and discharged through a rotary valve 14.
  • a relatively constant level of liquid is maintained in the impregnation tube, which is held at the desired preset pressure, by control of the temperature in the recirculation liquor.
  • the liquid level in tube 13 fall below a predetermined point less steam is supplied to the heat exchanger 26 with a resultant lowering of the temperature of the recirculation liquor which in turn reduces the amount of steam formed during flashing. This means that a greater portion of water remains in the liquor and accordingly the level of liquor in the tube 13 tends to rise.
  • the above described level control may be operated automatically by suitable means sensing level L and controlling the heat supplied to the heat exchanger 26 while the pressure is held constant.
  • the impregnation liquor may be controlled to maintain proper chemical concentration either manually or, if suitable equipment is available, automatically, by adjusting the amount of make-up liquor added in line 28 to give the desired concentration.
  • the concentration of the active cooking ingredient in the impregnation liquor is thus controlled to a predetermined value so that the chips leaving the impregnator will carry the correct amount of chemical to allow the digestion in the following stage.
  • the chips are never subject to the damaging action of the high concentration liquors.
  • the conveyor speed is variable and therefore the time of feed through the impregnation tube may be varied as desired.
  • the temperature maintained in said tube may be any suitable impregnation temperature.
  • the pressure of process steam removed via pipe 30 corresponds to the vapour pressure of the pool of liquor maintained in the impregnation tube.
  • the temperature of said pool can also be controlled to the proper impregnation temperature for the chips.
  • FIG. 2 A second impregnator system incorporated into a different type of diges-tor than that illustrated in FIG. 1 is shown in FIG. 2.
  • impregnation and digestion are carried out in one vessel while flashing occurs externally of the vessel.
  • the flashing system has been incorporated on an up flow digester wit-h impregnation occurring in the lower zone in the digester.
  • Liquor is withdrawn from the impregnation zone below the level L in the digester ⁇ 100 through line 25A and then proceeds through a heatexchanger 26A where it is heated by steam from line 27A. Fresh chemical is added to the system via line 2 8A.
  • the amount of heat applied in heat exchanger 26A is controlled in accordance with the level L"in the digester 100 in the same manner as the heat exchanger 26 is controlled in accordance with level L as described hereinabove.
  • Heated and fortified liquor is carried via line 29A into a flash tank 13A.
  • the flash tank is held at a pre-set pressure as was the impregnator 13, so that water will be flashed in the tank 13A.
  • the amount of water flashed depends on the difference in temperature between the heated fortified liquor in line 29A and the liquor in the flash tank.
  • Steam generated by flashing of liquor in tank 13A is removed via line 30B which would be connected .to the evaporator 44 as is line 30 of the first embodiment.
  • a pressure regulator valve 30C controls the pressure in the flash tank 13A.
  • liquor is returned to the impregnation zone via line 2913.
  • the liquor level L in the flash tank is held constant by controlling the flow through line 29B by means such as valve 29C.
  • the amount of flashing in tank 13A adjusts the chemical concentration of the fortified liquor and the control of flow through line 29B controls the amount of liquor circulated to the digester.
  • the present system of temperature control to flash a variable amount of water from circulated liquor may generally be applied where it is desired to hold the liquor to wood ratio at some value lower than that which would otherwise prevail as a result of water entering the system with the chips, the steam and the make-up liquor.
  • this method may be applied regardless of the design .of the digester, or the direction of chips flow (i.e. up,
  • the cooking tube 15 is of similar construction to the impregnation tube 13 and is provided with a flight type conveyor schematically indicated at 31. As in the impregnator tube 13 the chips are carried downward along the top of tube 15. High pressure steam is injected into the cooking tube through a steam line 16 to maintain a predetermined cooking temperature. Cooking time is controlled by the rate of travel of the conveyor 31, which may be varied to obtain proper cooking of the chips being digested.
  • a puddle of liquor may also be maintained in the tube 15 by controlled drainage. It is also possible to circulate some of the black liquor from the tube 15 reduced and the solids content of the black liquor in tube 15 would be increased. This liquor drained through line 32 is at still higher concentration than when direct steaming per se is used.
  • Digested chips exit at the top of the cooking tube 15 and pass through a rotary valve 18 into a diffusion washer schematically illustrated at 19.
  • the chips are carried .by the conveyor 20 in counter current flow to washing liquor entering through the pipe 37.
  • the chips after passing through washer 19 may then be fed to the inlet of a press washer 21 where a second washing step is performed.
  • the thus digested and washed stock is removed from the system via line 22.
  • the difiusion washer 19 consists essentially of a tube mounted at approximately the same angle to the horizontal as the impregnation tube or the cooking tube and has a screw type conveyor 20 for carrying the material upwardly through the washer as shown. Washing liquid is admitted toward the top of the washer by pipe 37 to proceed in counter flow to the material being carried by the conveyor 20.
  • wash Water from pipe 38 enters the press washer 21 with the digested chips through line 39.
  • the liquor from the press washer 21 is conducted via line 37 to the upper part of the diffusion washer 19 to proceed in counter flow to the digested stock.
  • all the wash liquid required is available as evaporator condensate obtained from a subsequent stage of the system.
  • a dilferent vform of washing system is illustrated in FIG. 3. In this system a pool of liquor 69 is maintained in the tube 68 in the line leaving the cooking tube. The stock from the cooking tube passes through the pool 69 and through valve 18 or the like into the line 61.
  • the line 61 conducts the stock to tank 62 from whence it proceeds via line 63 to a conventional rotary drum washer 64 the vat of which is at atmospheric pressure.
  • a portion of the liquor carries with the digested chips through valve 18 and is removed at the washer 64.
  • This heated liquor drains from pool 69 through strainer 67 and line 66.
  • the liquor in line 66 while still maintained at digester pressure is combined with the liquor drained through pipe 62 directly from digestion tube 15, and this combined flow of liquor is conducted via line 33 to heat exchanger 42 where the incoming digestion reagent is pre-heated.
  • the pre-heated incoming digestion re-agent then passes via line 28 to the impregnation system.
  • the supply of steam to evaporator 44 is supplemented, if necessary, by steam from line 30A which may be obtained from the boiler.
  • Vapour from evaporator 44 is conducted to a second evaporator45 through a line 46 while condensate from said first evaporator 44 feeds to a flash tank 48 via the line 47.
  • the steam from flash tank 48 is conducted through the line 49 into said evaporator 45.
  • the vapour from the second evaporator 45 provides a source of low pressure steam (approximately 5 p.s.i.g. for
  • black liquor at a high temperature provides a convenient source of heat which may easily be recovered in line 41.
  • Black liquor at digestion temperature and pressure drained from the tube 15 in line 32 is added to the liquor in line 41 to supplement the heat source.
  • black liquor from lines 32 41 are conducted via line 33 while still maintained at elevated pressure to a heat exchanger 42 which serves to heat the make-up liquor supplied to the system. From heat exchanger 42 the black liquor proceeds to a flash tank 43. Vapour from said flash tank 43 is available for further use, for example, in the presteamer 11.
  • Black liquor from flash tank 43 is fed via line 53, oxidization tower 54, if required, and line 55 into evaporator 45 and from evaporator 45 to evaporator 44 through line 56.
  • an oxidation tower may be dispensed with and the residual liquor fed directly from the heat exchanger to the evaporator 45.
  • the evaporated liquor from evaporator 44 enters flash tank 58 through line 57 and the steam produced in tank 58 is added to the low pressure steam in line 50 through pipe 59.
  • Concentrated black liquor from tank 58 is conducted by line 60 to a suitable recovery system for incineration of chemicals and recovery of heat.
  • a further source or heat economy is available from the incineration of chemicals as there is less inorganic material present and therefore less heat is carried away.
  • Chips are steamed in the presteamer 11 using 700 lbs. of vapour for 6820 lbs. of moist wood containing 2730 lbs. H O as moisture, and this wood along with 3430 lbs. or" water at 212 F. pass on to the impregnation tube 13.
  • a temperature of 282 F. is maintained in the impregnation tube 13 by re-circulating liquor heated to a temperature of 311 F. by the heat exchanger 26.
  • This re-circulating liquor has a ratio 15 to 1 in this example (15 parts recirculation liquor to 1 part make-up liquor) with the liquor entering the impregnator at a concentration of 33.7 gums/litre of eflective Na O and removed therefrom at 30.5 guns/litre with the added make up liquor having a concentration of 90 grms./litre of eflect-iv'e N a O at a temperature of 282 F.
  • the temperature of the incoming re circulating liquor is adjusted to give the amount of evaporation required, to maintain a proper level of liquid in the impregnation tube.
  • I-mpregnated chips are carried through valve 18 to the cooking tube which in this example is kept at a temperature of 365 F. using 1135 lbs. of high pressure steam. 4920 lbs. of black liquor at 365 F. drain from tube 15 via line 32.
  • Process steam in line 30 is supplemented with 1200 lbs. of steam at 35 p.s.i.g. from the line 30A from a boiler or other suitable source, to supply a total of 3600 lbs. of steam to the first evaporator 44.
  • Exiting from the evaporator 44 are 3320 lbs. of steam evaporated from the black liquor at 251 F. and 3600 lbs. of condensate.
  • the steam from evaporator 44 is fed to evaporator 45 while condensate from said evaporator 44 is flashed in tank 48 to produce lbs. of steam at 251 F. and 3490 lbs. of condensate.
  • the steam from flash tank 48 is also fed to evaporator 45.
  • Evaporator 45 produces .2510 lbs. of process steam at 227 F. by evaporation of black liquor and 3430 lbs. of condensate.
  • This condensate is added to that from the flash tank 48 for a total of 6920 lbs. of condensate at 251 F. which is passed in heat exchange with incoming cold water andthen 5840 lbs. of said condensate at 200 F. is supplied to the washer via line 38 with the remainder of the condensate going to the recovery system for use in dissolving the smelt.
  • Table 1 given below is a comparison of the heat economy of the disclosed continuous digestion system just described with a batch system. Unbleached spruce Wood Cl'llPS were used in this comparison.
  • Example 1 herein below demonstrates one mode of operation of the continuous digestive system disclosed using the kraft process and includes a description of the pulp produced in this example, the washing systems disclosed were not used.
  • Example 1 Spruce chips, containing 40.5% moisture were fed at a rate of 2.42 lbs. per minute of moisture-free wood to the presteaming tube of a pilot plant continuous digester similar to that shown in FIGURE 1. Steam was admitted to the tube at a rate sufficient to maintain a pressure of p.s.i.g. The condensate formed was drained from the bottom of the tube. The conveyor speed was set so that the residence time of the chips in the presteaming vessel was 5 minutes.
  • the presteamed chips were introduced into an impregnating tube in which a liquor level was maintained up to
  • the chips were carried through this vessel by means of a flight conveyor, the speed of which was maintained to give a residence time of 30 minutes for the impregnation.
  • the concentration of effective alkali in the feed liquor was maintained at 32.6 grams per liter by adding fresh liquor to liquor which was being recycled through the circulating line. In order to maintain this concentration, a liquor flow of 0.5 Imperial gallon per minute at a concentration of 84.0 grams per liter was established.
  • the fresh liquor was made up to a sulfidity of 30% while the liquor in the impregnating tube reached equilibrium at a sulfidity of 45%.
  • the liquor in this tube was maintained at a temperature of 136 C.; and a pressure of 30 p.s.i.g.
  • the liquor was superheated to a temperature of 145 C. in a heat exchanger in the circulation and allowed to flash to 136 C. so that a water balance was maintained in the impregnation tube.
  • the chips were introduced into the cooking vessel'which was held at 150 p.s.i.g. by the addition of direct steam.
  • the retention time of the chips in the cooking zone was 30 minutes.
  • Condensate and the liquor which drained from the chips as the digestion proceeded were removed from the bottom of the digester, the cook being carried out essentially in the vapor phase.
  • the chips were 10 removed from the digester through a rotary valveand-allowed to flash to atmospheric pressure.
  • pulp samples were obtained from the digestor by blowing in the regular manner and also by cooling the digested chips to 212 F. before discharging.
  • the following table illustrates a comparison of the cold discharge with the hot blow.
  • a higher percent of heat from the system is in the form of high pressure steam than in conventional batch system. Also less total heat exchange area is required for digestion and evaporation than is the case for conventional batch operation and a high percent of secondary heat from the disclosed system can be recovered.
  • the impregnator and method of impregnating have been disclosed in relationship with pulp digestion systems. This method and apparatus could also be used in other environments for impregnation of materials which carry variable amounts of water and in which the impregnant is carried in water or other vaporizable liquid.
  • the amount of water added may be controlled by sensing the level andcontrolling the water added to maintain level L substantially constant. Liquor concentration and temperature, the pressure in the impregnation tube and the time raw material and as water with the digesting chemical and leaves said system with the impregnated raw material, a method of impregnating said cellulosic raw material while maintaining a water balance in the system comprising: maintaining a pool of impregnation liquor in an impregnation zone, continuously feeding said cellulosic raw material to said pool, introducing heated impregnation liquor to said impregnation zone, said heated impregnation liquor being of a temperature higher than the temperature of liquor in said pool, controlling the temperature of said heated impregnation liquor to cause a portion thereof to flash and form process steam, the amount of said heated impregnation liquor flashed being such as to maintain the level in said pool substantially constant and then removing said process steam from the system.
  • a method of impregnating said raw material while maintaining water balance in said system comprising: maintaining a pool of impregnation liquor at substantially constant temperature in an impregnator, continuously feeding raw material to said pool, continuously removing liquor from said pool, indirectly heating said removed liquor to a temperature above said temperature in the impregnator, introducing said removed liquor into a zone of substantially constant pressure thereby to cause a portion of said removed liquor to flash, maintaining a relatively constant level in said pool by controlling the amount of heat applied to said removed liquor in accordance with the level in said pool, thereby
  • An apparatus for use in continuous pulping of cellulosic raw material wherein said raw material is subjected to impregnation with an impregnation liquor containing an aqueous solution of digesting chemical in an impregnation system, thereby to impregnate said material with digesting chemical in a predetermined weight ratio and wherein water enters said impregnation system as moisture with said raw material and as water with the digesting chemical and leaves said system with the impregnated raw material
  • said apparatus comprising; an impregator having a pool of impregnation liquor therein and a zone of controlled pressure above the level of said pool, circulating means for circulating impregnation liquor from said pool through an indirect heating means and back to said impregnator, means controlling the temperature of said circulating liquor in accordance with the level in said pool to cause a controlled amount of said impregnation liquor to flash in said zone of controlled pressure, thereby to maintain said level substantially constant, and means for conducting process steam produced by said flashing away from said impre
  • An apparatus for use in continuous pulping of cellulosic raw material wherein said raw material is subjected to impregnation with an impregnation liquor con taining an aqueous solution of digesting chemical in an impregnation system thereby to impregnate said material with digesting chemical in a pre-determined weight ratio and wherein water enters said impregnation system as moisture with said raw material and as water with the digesting chemical and leaves said system with the impregnated raw material
  • said apparatus comprising; a vessel having a pool of impregnation liquor therein, a flash tank, indirect heating means, means for circulating impregnation liquor from said pool to said indirect heating means and then to said flash tank, means for conducting impregnation liquor from said flash tank back to said pool, means for controlling the temperature of the impregnation liquor entering said flash tank in accordance with the level in said pool to cause a controlled amount of water to flash in said flash tank thereby to maintain the level in said pool substantially constant and means for
  • An apparatus for use in continuous pulping ofcellulosic raw material wherein said raw material is subjected to impregnation with an impregnation liquor containing an aqueous solution of digesting chemical in an impregnation system thereby to impregnate said material with digesting chemical in a pre-determined weight ratio and wherein water enters said impregnation system as moisture with said raw material and as water with the digesting chemical and leaves said system with the impregnated raw material
  • said apparatus comprising; a digester vessel, a flash tank, indirect heating means, said vessel having an impregnation zone filled with impregnation liquor and a digestion zone, means for conducting impregnation liquor from said digester vessel to said indirect heating means and then to said flash tank, means for conducting impregnation liquor from said flash tank to said digestor vessel, means for controlling the flow from said flash tank to said digester vessel While maintaining a substantially constant level of impregnation liquor in said flash tank, means for controlling the temperature of the impreg

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3532594A (en) * 1966-09-12 1970-10-06 Kamyr Ab Method of digesting cellulosic material in steam phase
US3549483A (en) * 1967-08-04 1970-12-22 Lummus Co Impregnation and digestion of cellulosic material in a single vessel
US4162215A (en) * 1976-06-18 1979-07-24 Bayer Aktiengesellschaft Displacement of a liquid A by a liquid B in a suspension
US4322184A (en) * 1979-12-05 1982-03-30 Kamyr, Inc. Apparatus for continuously feeding solid particles into a pressurized container having an improved lifting mechanism
US4954219A (en) * 1978-03-02 1990-09-04 Beloit Corporation Method for transfere of firrous materials transport by liquids
WO1999020827A1 (en) * 1997-10-16 1999-04-29 Kvaerner Pulping Ab Process system and method for preliminary treatment of disintegrated cellulose-containing material prior to pulp digestion
US20050115691A1 (en) * 2002-01-24 2005-06-02 Lindstroem Mikael Cooking of cellulose pulp in a cooking liquor containing preevaporated black liquor
US20060070710A1 (en) * 2004-10-04 2006-04-06 Lasse Hernesniemi Method and a device for preparing cellulose pulp
WO2006037860A1 (en) * 2004-10-04 2006-04-13 Metso Paper, Inc. Improved alkaline process and system for producing pulp
US10240287B2 (en) * 2014-09-12 2019-03-26 Andritz Oy Heating of hydraulic digesters
EP3464715B1 (de) 2016-06-06 2021-07-28 Andritz Oy Verfahren zur herstellung von zellstoff in einer aufschlussanlage einer zellstofffabrik
CN113299253A (zh) * 2021-05-25 2021-08-24 李成兵 一种防裂笛子的制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2205374A (en) * 1936-07-02 1940-06-18 Chemipulp Process Inc Digesting process and apparatus
US2809111A (en) * 1956-02-13 1957-10-08 Condi Engineering Corp Apparatus for wood chip digestion

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2858211A (en) * 1956-02-13 1958-10-28 Condi Engineering Corp Apparatus for wood chip digestion

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2205374A (en) * 1936-07-02 1940-06-18 Chemipulp Process Inc Digesting process and apparatus
US2809111A (en) * 1956-02-13 1957-10-08 Condi Engineering Corp Apparatus for wood chip digestion

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3532594A (en) * 1966-09-12 1970-10-06 Kamyr Ab Method of digesting cellulosic material in steam phase
US3549483A (en) * 1967-08-04 1970-12-22 Lummus Co Impregnation and digestion of cellulosic material in a single vessel
US4162215A (en) * 1976-06-18 1979-07-24 Bayer Aktiengesellschaft Displacement of a liquid A by a liquid B in a suspension
US4954219A (en) * 1978-03-02 1990-09-04 Beloit Corporation Method for transfere of firrous materials transport by liquids
US4322184A (en) * 1979-12-05 1982-03-30 Kamyr, Inc. Apparatus for continuously feeding solid particles into a pressurized container having an improved lifting mechanism
WO1999020827A1 (en) * 1997-10-16 1999-04-29 Kvaerner Pulping Ab Process system and method for preliminary treatment of disintegrated cellulose-containing material prior to pulp digestion
US6280567B1 (en) * 1997-10-16 2001-08-28 Kvaerner Pulping Ab System and method for treatment of cellulose-containing material prior to pulp digestion
US20050115691A1 (en) * 2002-01-24 2005-06-02 Lindstroem Mikael Cooking of cellulose pulp in a cooking liquor containing preevaporated black liquor
US7351306B2 (en) * 2002-01-24 2008-04-01 Metso Fiber Karlstad Ab Cooking of cellulose pulp in a cooking liquor containing pre-evaporated black liquor
WO2006037858A1 (en) * 2004-10-04 2006-04-13 Metso Paper, Inc. A method and a device for preparing cellulose pulp
WO2006037860A1 (en) * 2004-10-04 2006-04-13 Metso Paper, Inc. Improved alkaline process and system for producing pulp
EP1797235A1 (de) * 2004-10-04 2007-06-20 Metso Paper, Inc. Verbessertes alkalisches verfahren und system zur herstellung von zellstoff
US20070256801A1 (en) * 2004-10-04 2007-11-08 Lasse Hernesniemi Alkaline Process and System for Producing Pulp
US20060070710A1 (en) * 2004-10-04 2006-04-06 Lasse Hernesniemi Method and a device for preparing cellulose pulp
EP1797235A4 (de) * 2004-10-04 2010-10-06 Metso Paper Inc Verbessertes alkalisches verfahren und system zur herstellung von zellstoff
CN101068977B (zh) * 2004-10-04 2011-05-11 梅特索纸业股份有限公司 用于生产纸浆的改进的方法和系统
US10240287B2 (en) * 2014-09-12 2019-03-26 Andritz Oy Heating of hydraulic digesters
EP3464715B1 (de) 2016-06-06 2021-07-28 Andritz Oy Verfahren zur herstellung von zellstoff in einer aufschlussanlage einer zellstofffabrik
CN113299253A (zh) * 2021-05-25 2021-08-24 李成兵 一种防裂笛子的制备方法
CN113299253B (zh) * 2021-05-25 2024-05-07 李成兵 一种防裂笛子的制备方法

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DE1246384B (de) 1967-08-03
FI46087B (de) 1972-08-31
GB1035456A (en) 1966-07-06
FI46087C (fi) 1972-12-11
FR1372871A (fr) 1964-09-18

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