DE1281828B - Device for the continuous production of cellulose - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN W ¥ W PATENT OFFICE

EDITORIAL

Int. CL:

D21c

Number:
File number:
Registration date:
Display day:

German class: 55 b -2/10

P 12 81 828.9-41 (J 22861)

November 20, 1962

October 31, 1968

Pulp is made by processing wood chips or other fiber material in a series of successive treatment stages in which the following operations are used come:

Soaking and, if necessary, heating the chips with a liquid to form the suitable one Mixture of solid particles and liquid; chemical treatment of the chips, usually under Pressure and for a significant amount of time. Often several chemical treatments take place, whereby care must be taken that the chemical agent used first causes the subsequent chemical reaction not bother.

In the German patent specification 939126 a only fed fibrous material mixed with cooking liquor through the container and the liquor drawn off through sieves and returned in a rewarmed state. According to the invention, however, two Treatment zones that are to be kept precisely separated for treatments with different chemicals in formed a vessel. For this it is necessary that the reagents to be used on the one hand carefully and easily removed while maintaining two standing treatment zones will.

The device according to the invention enables a complete multi-stage pulp production in one single vessel, with multiple treatments applied using different chemical reagents will.

The device according to the invention for the continuous production of pulp in a vertical Stove with a drain attached at its upper end and a drain attached at its lower end Pushing device, several sieves arranged along the vessel at a distance from one another Feed and discharge devices consists in that the sieves are arranged so that a first treatment zone between the chip lift plate and the first screen, a second treatment zone between the second sieve and an upper sieve and a middle buffer zone between the first sieve and the next following upper sieve is formed, whereby the treatment of the fabric with different Reagents is made possible. Preferably there is between the first sieve and the next one A discharge device for controlling a valve is attached to the upper sieve.

Due to the device according to the invention, a new method is made possible, wherein an im general vertical elongated compact equal-

Device for continuous production
of pulp

Applicant:

Inproved Machinery Inc., a company
under the laws of the state of Delaware,
Nashua, NH (V. St. A.)

Representative:

Dr.-Ing. H. Ruschke

and Dipl.-Ing. H. Agular, patent attorneys,

8000 Munich 27, Pienzenauer Str. 2

Named as inventor:

Lloyd N. Lang, Chicago, JIl. (V. St. A.)

Claimed priority:
V. St. v. America November 20, 1961
(154931)

moderate mass of wood chips with a substantially uniform cross-section in a cooker is continuously maintained by moving the wood chips up to the bottom of the mass column guided along the path of the mass and pressed against the lower end. During their As the movement progresses, the wood chips are treated with appropriate chemical agents, these treatments taking place within several successive zones. These zones consist of a lower zone in which the wood chips are treated with a first chemical agent and a subsequent upper zone in which the chips moving upwards treated with a second chemical agent, whereupon the wood chips treated in this way can be removed at the top. It is essential that most of the first chemical Means at the top of the lower zone and removed most of the second chemical agent is added at the lower end of the upper zone. An effective addition of the second chemical This means that the addition or, preferably, the removal of the first chemical can be achieved By means of an appropriate measuring device, for example a measuring device for measuring the pH value, is controlled, whereby between

809 629/1363

³ 4

The two treatment zones form a buffer zone, while their peripheral edge is on the inner wall forms. It has also proven to be very effective if the reaction vessel 22 rests tightly so that a the movement of the treatment media in one to pass the chips into the lower portion of the the feed of the wood chips opposite reaction vessel 22 is avoided. Direction takes place. 5 For supplying the pressurized mixture

It should be noted that the lifting force - only from chips and liquid to the upper surface a tubular part 42 serves on the solid particles at the lower end of the cooker of said plate, is exercised. As a result, there is a running front of its inner wall concentric to the shaft 30 and in the thrust the particle upward by the length of the spacing therefrom and whichever is at the Kochers. This upstream movement is applied from the lower surface of the screw plate 32 special significance and also the fact that is and extends downward from it, whereby a columnar mass of chips through the im one central opening between the upper and the lower part of the column pressure exerted by the lower radial edge of the screw plate The vessel is pushed up through it. Here- will.

through is the useful length of the vessel on the one hand 15 The lower end of the shaft 30 extends in completely used and on the other hand remains completely a (not shown) hydraulic cylinder, free of interference, and besides, the required becomes rather below the lower end of the reaction uniform Circulation of the treatment agent vessel 22 is attached and forms its piston ensures. and provided with a corresponding pressure medium source

The invention will hereinafter be related to the reciprocating motion of the plate Drawings explained in more detail, in which to lift the shaft with the screw plate 32,

1 shows a side view of a preferred embodiment, the pressure force in the vessel against the upper one management form of the device according to the invention the end of the shaft is so large that the missing and pressure in the cylinder the plate is lowered quickly,

FIGS. 2 to 5 show schematic views of particular 25 in which, in such cases, the pressure vessel 22 is used as a Show construction of the device according to FIG. Accumulator is used, which the necessary power

The preferred device according to FIG. 1 is the one that can give up quickly. Furthermore, entin changes U.S. Patent 2,878,116 shown somewhat speaking of the reciprocating motion of the shaft 30 similar, but according to the invention it has more than one volume of liquid displaced by it so that spaced apart, as a filter or 30 that the entire volume of liquid in the vessel 22 over Sieve open openings. In general, it sways back and forth a limited distance. Exists the device from an upright, in the speaking (also not shown) means to the essential change cylindrical elongated pressure vessel have connection with the pressure or the output or Cooker 22 with a practically uniform puff can be used to move the screw cross-section back and forth, the upwards at least not smaller 35 benplatte 32 at any speed and it has a top opening 23 as well as one may also be provided.

lower opening 18 which connects to a pump 16. The upper outlet mechanism has an outlet collar is on, which in turn is connected to a device 26 which is located at the upper end of the Liquid inlet 12 provided vessel for mixing vessel is attached and for removing the the swarf is connected to the liquid. 40 digested pulp and for feeding the pulp The cooker also has a lower entry into a vertical chamber 48. In the lower opening 17 open. At the top of the device is the zone of the chamber, generally called the at the outlet opening 20 / which has an ent volume below the flange connection shown (not shown) slurry storage tank is designated, is an upward is connected, an upper exit mechanism provided 45 paddle stirrer 50 is rotatably mounted and operational. It is important that the vessel 22 be moderately connected to a drive 52, which preferably is generally uniform cross-section is an electric motor. A lower instructor although it tapers slightly and thus the area of the chamber corresponds essentially to the and forms a gradually increasing cross-section of the path of the lower edge of the rotating blade forms, with one for example approximately 50 forming the lower end of the lower zone. At least one P ^ mm diameter enlargement per 30 cm as opening 56 is in the lower zone of the chamber Has proven expedient. Those in the above the lower surface below the path of the Patent detailed illustrated and Beschrie- Schaufelführer provided so that when turning the The same feed device has one - in one in the paddle stirrer, each paddle at the entrance of the Compared to the vessel length limited distance 55 wipes the opening and thus any blockage within the reaction vessel 22 - avoids in the vicinity. The opening 56 is through corresponding its lower end connected to the atmosphere by means of a pipe. A lockdown Part of the vessel and, generally, axial valving may be placed in the opening as desired to the extending shaft 30 rotatable, reciprocating 56 for adjusting and closing the same preceding Snail, which can be seen in detail as a 60.

Single turn screw plate 32 with several except for the lower opening 17 and 18 are inven-

Holes, the number of which allows an essentially free, according to several sieves along the length of the vessel, to allow the liquid to pass through, but are spaced apart and liquids which are so small that they can pass through keitsspiegel- and flow control devices. How to avoid chips or other fiber material, 65 in Fi g. 1 , represent six such sieves throughout. The bottom to top of the plate called the screw shoulder is a typical example of a flat plate closed by a very flexible system of a two-edged process extending between its upper and lower parts, separated stages for the treatment of the layers therein

Wood chips with different chemical solid particles or in the opposite direction see reagents. The sieves are in general can take place. The use of Siebeinrich-, lines evenly along the length of the vessel at a distance is arranged for the introduction of the liquid into each other and do not form two hand- the vessel, but this creates ventilation zones with an intermediate buffer zone, ie the use of sieve devices instead wherein a first treatment zone between the chip simple inlet openings, the flow reversal lifting plate 32 and the sieve 63, enables a second handling without changing the digester,
Lung Zone Between Screen 64 and Upper Screen The operation of the apparatus 66 of the present invention and a central buffer zone between screen 63 has been generally described above. To and the next following upper sieve 64 is located. A particular flow system, mirror sensing device 70, is to be explained accordingly, should be mentioned, brought in order to discharge the liquid level above the upper, that the wood chips and the first chemical reagent sieve 66 and below the outlet opening 20, mixed in the vessel 14 and then into the reaction sensing, the uppermost end of the second treatment vessel 22 are transferred, where the chip component (if such is desired) to delimit and slowly upward through the chip mass, the medium outlet through the actuated valve 79 of the by means of actuation of the Plate 32 sent to regulate upper screen 66. Further facilities will be. The medium flow in the lower area is used to regulate the liquid level and the lowest treatment zone between the sieve flows as well as for heating (if desired) 61 and 62 takes place in a direction which and for regulating the corresponding level the ao direction of the wood chip movement - like in Fig. 1 Interface between the upper and the lower indicated by the arrow - is opposite - and the chemical treatment zone is provided. The penultimate feature of the device according to the invention direction 76 as a result of the actuation of the pump, the medium flow in the upper area between the sieves 62 and 63 due to the mutually incompatible successive 25 output of the valve 74 in one for its effective operation Direction instead of the reagents, as it often occurs, of which the direction of the movement of wood chips is of crucial importance, the problem being corresponding to. Similar flow conditions prevail in the device according to the invention in a single one in the upper treatment zone, with an opposite way being solved by not only creating a steady flow between the sieves 64 and 65 intermediate buffer zone, but also a continuous 30 in order to remove the chemical reagent, which in the Control of the speed of removal of the screen 65 was introduced, downwardly by moving the lower first chemical treatment reagent out of the area of the upper treatment zone, lower treatment zone provided by measurement and being as a result of the exit of the valve 79, was provided. The measurement can be made at the sieve 64, which is one which is actuated by the mirror control device 70 separating the lower from the upper treatment zone, a rectified flow in the upper area of the outlet, is easily made in the treatment zone, so that a liquid becomes and represents each any value of the reagent keitsspiegel under the wood chip outlet opening 20 in the lower zone, whereby it is created in terms of value. The interface is within the pH value, which is indicated by a de- buffer zone between the sieves 63 and 64 maintained by the speaking pH measuring and control device 72 40 operating the discharge device 72, which has a valve 74 in the medium - which controls the valve 74 through which the first outlet line of the screen 63 is actuated. The medium chemical reagent is sucked off, whereby the outflow within the device can be addressed by a value of the first chemical by creating a lower countercurrent reagent which appears at the lower area within each of the treatment zones 45 at the end of the upper treatment zone . Before means of the intermediate sieves 62, 65 and the lower one, there is preferably no medium flow through the sieves 61, 64 of each treatment zone by means of the buffer zone. The mirror control device 70, including devices 76, 78 including their associated valve 79, actuates in the usual way that speaking pumps are regulated. Heating can also be provided to control the speed of ejection of the second devices 76 and 78, respectively, to control the reagent.

around the lower or upper treatment zone to In F i g. 2 to 5 are special modifications of the

warm up if desired. The inlet for the device according to the invention for multi-stage

the first chemical reagent to the lower zone can be presented treatments.

through the inlet 12 of the vessel 14 for the In F i g. 2 is the application of the device for

Wood chips-liquid mixture extend, while 55 a continuous process for the treatment of

rend is its outlet on the sieve 63, which wood chips first with NaHSO ₃ and then with

is controlled by the valve 74, as already shown above liquid SO ₂ . So it becomes a 5- to 10% grade

mentioned. The inlet of the second chemical reagent solution of NaHSO ₃ with a pH of about

can be introduced through the mixing vessel inlet 12 at the sieve 65 and its outlet at the sieve 66 4.5

located, which through the valve 79 and its 60 and in the vessel 14 before introduction into the pressurized

Control device 70 is controlled. Further incorporation and working reaction vessel 22 mixed. After

Outlet elements, if necessary for any introduction, the chip mass is initially through

Flow system, can also provide counter-flowing liquid in the lower area between

will. see the sieves 61 and 62 at a temperature of

This construction allows great flexibility 65 heated to about 163 to 172 ° C, whereupon the mass at

of the operation, as this results in the treatment with that of its further upward movement through the upper

Liquid by means of a multi-stage process on one- area of the lower treatment zone between the

then either in the direction of the feed sieves 62 and 63, where a rectified liquid

Claims (1)

7 8 keitsströmung arises, appropriately soaked and the medium flow generally corresponds to dersulphonized will, those which was discussed in relation to Fig. 2, At the sieve 63 delimiting the upper end of the lower treatment with the NaHSO ₃ reagent at the chip vessel inlet zone, a portion of the NaHSO ₃ - 12 is introduced for unidirectional flow through the lower solution through the control valve 74 to the corresponding treatment zone, except for the recovery removed , and the chips within the area between the sieves 61 and 62, where their mass flow upwards through the buffer zone, flow expediently in the opposite direction through between the sieves 63 and 64 and in the ter direction, while the heating for the lower area of the upper treatment zone takes place Between the treatment in the rest of the lower treatment the sieves 64 and 65. The second chemical zone between the sieves 62 and 63 at about 148 liquid, which is carried out by means of an appropriate injector up to 165 ° C and the pH value about 4.5 to 5.0 outside the vessel 12 by concentrating. The treatment in the upper zone with the remaining NaHSO ₃ solution with SO ₂ obtained Na ₂ CO ₃ takes place at a temperature of about 166 ° C., the counterflow occurs at the sieve 65 and a pH of 8.5 takes place , with the reagent passed, flowing outward at sieve 64. 15 then at the upper sieve 66 under control of the wood chips with a liquid level control device 70 is removed. Soaked within a higher SO ₂ concentration. A part of the upper treatment zone finds a counteracting NaHSOj solution moves upwards through a set flow within its lower area, the buffer zone between the sieves 63 and 64. As by means of heating and the pump 78, the pH value of the treatment takes place in the upper one Zone 20 has a unidirectional flow in its upper approximately 1.5, the pH sensing and control range is in place. The liquid interface is arranged in the device 72 so that it is addressed by a buffer zone between the sieves 63 and 64 with no pH value of about 1.5 and the liquid flow is maintained between them, the presetting opening of the valve 74 expands if the pH increases. When the sensed pH value is sensed at the upper sieve 64, the sensed pH increases, and the opening 25 and 12 is reduced to about 8.5 by actuation of the valve 74, if the sensed pH is kept below that, by the substantial removal of that value falls. whole free NaHSO ₃ reagent from the chips Above the sieve 65, the SO ₂ reagent flows to ensure the introduction of the Na ₂ CO ₃ reagent into the same through the upper area of the upper treatment area. . zone between the sieves 65 and 66 for a further 30 In Fig. 5 is the application of the invention and final treatment of the wood chips, with the appropriate device for a continuous Verbis for removing the SO ₂ reagent at the top drive for treating the wood chips after the sieve 66 in In that area, a rectified flow-prehydrolylic force process is shown, with formation and the liquid level above the cooking liquor being a mixture of waste liquor and, by means of the mirror sensing 35 actuating the sieve valve 79, white liquor, and the latter mainly device 70 being controlled. The treated chips are then removed, which is a mixture of NaOH, Na ₂ S and Na ₂ CO _3. water hydrolysis and during the Kraft boil In Fig. 3 the application of the invention extraction precedes. Then water or a corresponding device for a process is shown, dilute sulfuric acid _{solution through the chip in which instead of an SO 2} solution, gaseous SO ₂ 40 mixing vessel inlet 12 is introduced and used with the and the direction of the medium chips brought into the lower treatment zone, where flow is changed. In particular, the sieves such as sieves 61 and 62 belonging to them by opposite flow between the lower treatment zone are heated and used upwards with previously, only that a fresh NaHSO ₃ - 45 extraction is now available at the upper sieve 63 of a flow in the same direction as the hydrolytic of the lower treatment zone of the hemicellulosic portion of the wood chips reagent is introduced, with a countercurrent flowing until it is removed at the sieve 63, through the entire length of the lower treatment zone which takes place through the upper end of the lower treatment and limits the removal at the zone. In the upper treatment zone between the opening 17 below the plate 32 takes place, although see the sieves 64 and 66, the chips will also be removed from the lower sieve 61 50 of the heated white material introduced at the intermediate sieve 65. The lye treated at the chip mixing vessel inlet 12, which liquid carried in the opposite direction, can also be removed through the opening tang in the lower area between the sieves 65 and 17. 64 flows and the wood chips to about 177 ° C for The buffer zone between the sieves 63 and 64 is its treatment during the upward flow to control the NaHSO ₃ reagent level and the 55 between the sieves 65 and 66 is heated. The boundary mirror device 70 for actuating its valve surface is as before used within the buffer zone by 74, so that the area lying on it, the control of the pH transition to alkali including the entire upper treatment zone of the right, with the lower treatment zone effect of the gas introduced through opening 63 has a pH of less than 7 and the upper shaped SO _{2 is} exposed. The uppermost sieves 65 60 treatment zone have a highly alkaline pH value and 66 are not required here, which has from over 10 to 12. The uppermost liquid-gaseous SO _{2 level} after the opposite flow is controlled as before, the treated is removed through the upper treatment zone through sieve 64 of wood chips through the outlet opening 20 at its lower end. will. . . In Fig. 4 the application of the invention is 65 patent claims according to a continuous device. ■ ^e '. ...... drive to the treatment of wood chips initially with 1st device for continuous production NaHSO ₃ and then Na ₂ CO ₃ shown. The direction of pulp in a vertical digester using drainage device attached to its upper end and pusher device arranged at its lower end, several sieves arranged along the vessel at a distance from one another with feed and discharge devices, characterized in that the sieves. (61, 62, 63, 64, 65, 66) are arranged so that a first treatment zone between the chip lifting plate (32) and the sieve (63), a second treatment zone between the sieve (64) and the upper sieve (66) and a middle buffer zone between the sieve (63) and the next following upper sieve (64) is formed, whereby the treatment of the substance is made possible with different reagents. 2. Apparatus according to claim 1, characterized in that between the sieves (63) and (64) a discharge device (72) for controlling the valve (74) is attached. Considered publications:
German patent specification No. 939126. 1 sheet of drawings 809 629/1363 10.68 © Bundesdruckerei Berlin