DE1517144A1 - Method and arrangement for washing and cooling at the outlet end of a continuous cellulose digester - Google Patents

Description

DH. ING. ERNST MAIER PATSJTTANWAIT

8 MUNICH 22

A 9365 1. Wtpz 196?

EM / F / Si

AKTXBBOLAGBT KAHYR, Karlstad / Sweden

Procedure and arrangement for washing and cooling at the discharge end a ·· continuously working cellulose carbon

The invention relates to a method and a Arrangement for implementation in an elongated cellulose cooker, in which a fiber material is continuously fed in the length direction of the digester is digested by boiling with a cooking liquor under high pressure and at high temperature, a washing «and Cooling treatment of the fiber material immediately before this »usually in connection with the relaxation of at least the larger part of the cooking pressure, through an outlet on that a sin of the cooker is carried out.

For this purpose it is known to be close to the Cooker outlet is a liquid, for example white water or

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SparkatM Sdiramfaare Banfchaut Paul KopC, SMigaii Bankhaui K.Aw (MuMr.München Foiudwdi ShiH _B ait 732St MümJien 15386! T »l» eramnr> odraJMi Patatse.ilor BATH ORIGINAL

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• To add piltrate contained in coal liquor residues, where ·! di · liquid in countercurrent to the fiber material sub flowing is brought to thereby cool the Faeermaterial su as well as to wash the cooking liquor out of it. the The liquid supplied at the KooherauslaJ then generally has a comparatively low temperature in order to achieve effective cooling of the fiber material, so dal the washing process is also carried out at a low temperature.

However, in order to carry out an effective washing a high temperature is required, as it is not only important to use the cooking liquor and the products it dissolves from the spaces between the fiber bundles, but also the chemicals from the finer ones To remove pores of the material, which can only be achieved by diffusion and therefore by a high temperature is favored *

The aim of the invention is effective cooling as well effective washing of the fiber material at the outlet end of the Koohers. In order to achieve this goal, inventive act is used a washing treatment at a distance from the KooherauslaJ Help «a liquid which is outside the

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Kochers is heated to tine tempamtur »which is higher al * the temperature of the stove closer to its outlet Liquid supplied to cooling. Preferably one and the same amount of liquid first for cooling and then Used after heating to wash the fiber material> where "like" is another feature of the invention that is The above-mentioned goal is achieved by the fact that the liquid which has been sieved off from the fiber fabric and the liquid contains “those from the stove outlet for cooling closer supplied liquid exists or has been displaced by this, heated outside the digester and xu this is returned as washing liquid. The liquid coming from the digester is returned to this after it has been heated has been "withdrawn 1st" can also contain liquid, which has been prepared once or several times passed through the fibrous material for its washing 1st. In this way a loop is formed «in which j the liquid circulates so that the same amount of liquid « repeated through the fiber material on one and the same Route Hindu and «wipe each such pass in that fill iii loop is heated, which is made up of * »Is located outside the Koöhers, the heating preferably takes place the dta cooker au »Waio & iii supplied or to this

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returned liquid through heat exchange with the lifted the used cooking liquor withdrawn from the cooker.

The invention is described below in connection with of the accompanying drawing “the one in echeaatlech way shows continuously working Koohanlage according to the invention, described in more detail.

In the drawing, 11 denotes a steam boiler,

in which wood chips or other finely chopped cellulosic fiber material that is fed via a low-pressure rotary valve 15 is supplied, heated by Kleder pressure steam which is fed via a line 17 «where the material stirred and the end of the steam boiler ”with With the help of a screw conveyor 19 is fed * by the desired overpressure, about 1 atm Control valve 21 maintained. A suitable cooking liquor,

. for example sodium hydroxide solution, is passed through a pipe 22 fed. The mixture of lye and wood chips is used in the upper end of a standing cylindrical Koohers 25 with Using a high pressure rotary valve »23 initiated around by Steam heated, which from a line 26 partially Ubev a «n Rotary valve 22 to support its emptying and partially directly to the upper end of the digester and in an amount that is supplied by the in this "?" Herrsohen-

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the pressure is regulated. A further heating of the lye and schnitzel mixture takes place through a circulating loop, which contains two sieve belts 35 » 31» which are inserted into the digester wall and connected alternately, a pump 39, a heat exchanger 41 and a return line 43. This line, which is located in the middle of the cooker and the lower end of which is located in the middle of the cooker cross-section, preferably slightly above the level of the sieve belt 35 *, serves to reintroduce the circulating liquor, which is drawn off through the sieve belt and is removed from the heat. * has been heated exchanger to the digester. the circulating liquor is heated to a temperature of 170 ⁰ C, and in the digester, a hydraulic pressure is maintained atmospheres gauge of about 10. During the slow and gleichmässlgen descent of Paßermaterials through the digester reacts this with the cooking liquor, so that the fiber material is completely opened up when it reaches the height of the sieve belt "53, which is inserted into the cooker wall and is at a considerable distance from the outer end of the cooker, for example at a" distance from it lower end «which is approximately equal to a third of the length of the digester * The pasernat is made in the remaining lower part of the digester erial washed in a catfish described in more detail below and chilled so that it is almost

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is completely free of cooking liquor and oiled chemicals and has a considerably reduced temperature "when it reaches the lowest end of the stove" In. The material is conveyed near the bottom in a centrally arranged outlet 45 with the aid of a motor-driven scraper or agitator device 47 and transferred via a line 49 to a blow-off container 44, in which the outside air pressure or a slight overpressure is maintained. As a result of the pressure drop low Danpfnenge is discharged, especially if, in spite of the cooling in Kocherauslal the material still has a more than 100 ⁰ C lying temperature * This Danpf is discharged through a AuslaJ 46 at the upper end of Abblasbehälters, while the pulp duroh a lower AuslaJ 48 and via a line connected to this, in which a valve 50 is located, which is controlled by the height of the pulp in the blow-off container, is fed to the pulp container 52 of a rotary suction filter. A pulp layer 56 is taken up by the non-running sieve drum 54 of this filter. B. warm or cool fresh water supplied through spray nozzles 58 is washed. Part of the filtrate, which consists of wasoh water and cooking liquor residues, is collected in a container 60, from which it is fed with the aid of a pump 65 via a line 51 and into

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this is used to according to the invention and in a following described in more detail a cooling at the outlet and • Already in the first washing out of the cooking liquor from the pulp in the lower part of the cooker

The sieve belt 53, which is made of a perforated or slotted cylindrical screen plate, 1st flush with 'the cylindrical wall of the cooker, and on the outside of the Sieve plate is widened to the Kooher wall, so that a Samrael- | Space 55 is available for the used cooking liquor, which has been sieved from the fiber material moving past the sieve. This collecting space is old one via a line 57 Steam absorption device 59 connected, which is preferably designed as a cyclone »The one provided at the upper end of this cyclone Steam outlet is via line 17 with the steam boiler 11 connected, so that in the cyclone a comparatively lower one overpressure is maintained. When the sieved cooking liquor enters the cyclone, it gives a large part of their heat content as steam, which is used to heat up the beetles is used in Däapfkessel * The cooking liquor enters with at a low temperature by means of a lower outlet and a Line 72 off. In which a valve 73 for regulating the Liquid «spiegelε dps cyclones 59 is located, and enters a second vapor separation device 74, which is preferably

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Also fine cyclone is formed * in which the line 72 opens tangentially. Zn Zyklon 74 becomes even lower Overpressure ale in the cyclone 59 or possibly the Maintain outside air pressure. The one delivered by Zyklon 7 * Steam can be used for hot purposes «with them only lower temperatures are required, for example for hot water treatment or for heating the cooking liquor supplied through the pipeline 22, which is carried out by the cooking liquor escaping from the bottom of the cyclone 74 through a line 82, in degslch a valve 80 for regulation the liquid level in the cyclone becomes one Plant for the recovery of the chemical content of the cooking liquor.

The line 51 is nit a hole in the vertical Drive shaft 87 of the scraper or stirring device 47 connected, which bore is connected to channels. ^ which are not provided with outlet or injection openings About the hub of the device 47 and its radially extending Arne are distributed «so that through the Hoohdruekpunpe 65 injected liquid approximately the same "- sig is distributed over the cross section of the digester. A part of this liquid enters Susanne with the 3chni11el-liquid-oeaisoh through the outlet 4 $ and serves as a thinner

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tion of the mixture to a consistency that is sufficient is low, it takes off easily in line 49 fϋβββη can. The remaining part of the liquid that is used for cooling and is used to wash the fiber material β, on the contrary « current is promoted to the direction of movement of the latter upwards and displaces the accompanying consumed Cooking liquor, so that this can pass through the sieve belt 5? is driven out and displaced from the stove. Therefore replaced the washing liquid the coal liquor in the spaces between the Schnitzelteilohen the continuously moving downwards Schnitzel column and moves up through it until it is brought together by the sieve belt 53 emerges with the Koohlauge.

The above- described cooking plant according to the invention is built so that washing in the lower part of the cooker is made possible at a higher temperature than the temperature which the λ piltrate flowing through the line 51 naturally has, the latter temperature for cooling the bevel material in the actual outlet 45 may be suitable «

A further sieve belt 86 is inserted into the digester wall slightly above the lower end of the digester,

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which also consists of a cylindrical slotted or perforated sieve plate, which is arranged flush with the digester wall part located directly above it. Behind the sieve belt in an even more widened part of the Kocheiviand there is a chamber 88 for the liquid that has been sieved off continues "which extends along the axis of the digester and concentrically with the line 4j5 and which has an opening in the middle of the cross section of the digester approximately at the level of the sieve belt. One side of the heat exchanger 94 forms part of the line 57, so that a Heat exchange takes place between the cooking liquor passing through line 57 and the washing liquid passing through line 90. The liquid, which the digester has been fed through the injection openings 89 of the scraping or stirring device 47 and moves upwards while cooling the fiber material, exits through the sieve belt 86 and is pumped through the heat exchanger by the pump 92 94 promoted, in "which they auxine considerably above 100 ⁰ C lying temperature, for example

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C., whereupon the liquid is returned to the boiler, in which it is distributed from the opening of the tube 96 radially in all directions. In the circulating loop described, the liquid is repeatedly brought into circulation before it is driven upwards through the seat column to the sieve belt 55. In this catfish is in the height of the Siebgürtela an effective and thorough heating of the Faeermaterials "effected in the mentioned höh · Temperature 86 so the washing Dafi of the fiber material la unte- λ ren end of the digester, since the diffusion of chemicals from inside the fiber bundle to the outside into the surrounding liquid is facilitated by the increased temperature "takes place much faster and more effectively than if the washing liquid introduced through the openings 89 were driven directly up to the Susi sieve belt 55.

Immediately below the Siebgürtels 55 A similar screen girdle 98 is disposed * The latter screened liquid circulation line 102 and an inner conduit 104 which · on this is connected by a pump 100 through a · ä Kussere 1st and extending along the axis of the digester, «To Kooher, in which it · from the opening of the line 102 radially in all directions

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emerges approximately at the level of the sieves 53 * 98. This course the washing liquid in the transverse direction through the sectional column serves to adjust the concentration the Koohlauge over the Kooherquersohnitt «so that the smallest possible amount of cooking liquor in the larger rooms of the Material remains * if it enters the zone Sieve belts 98 and 86 enters, in which a Dlffuslonswasohung takes place during its upward movement through which the sonic column becomes in the mentioned part of the digester the washing liquid is enriched with the chemicals extracted from duroh diffusion. As mentioned, the washing liquid occurs finally through the sieve belt 52 Susans with the Koohlauge that accompanies the schnitzel and by which the washing liquid is displaced.

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Claims (1)

Claim 1 × method for a langgestreoteten Cellule · "- is digested Cooker" in which a FasernaterIaI during its continuous feed and promotion in ά · ν longitudinal direction of the Keehers duroh Xoohen sit a Koohlauge under high pressure and high temperature "sun washing in Oegenstros and cooling amm Fibrous material can be removed before it is discharged through a period of sleep, because washing at a distance from the point of view through a liquid "soles" which is heated outside the stove to a temperature "which is higher than the temperature of the liquid" the stove is supplied closer to its outlet for cooling. 2. The method according to claim 1 »thereby marked« that the fluid from the fibers laterally exudes has been and the "wing" contains "the other." sur cooling closer to the Kocherau ·! as a liquid exists or has been displaced by it of the cooker and fed back to it as washing liquid will. 909811/0978 _BAD ? t process for an elongated cellulose digester, in which fiber material is broken down during its continuous supply and conveyance in the elongation of the digester by boiling with a cooking liquor under high pressure and high temperature, to wash the fiber material directly before it passes through a digester outlet is discharged, characterized daduroh, dal w the liquid that has been screened off from the fiber material and containing a portion of the cooler liquid, which is closer to the Xoeherauslal is lugeführt, aulerhalb of Xoehers heated uiut to this in a gröleren distance from Xooherauslal for use as washing liquid " is returned, 4. Method according to claim 1, Ϊ or 2, daduroh characterized, as the used, sieved and removed washing liquid from the digester is sent to this for further washing. is returned.
Ϊ 5. The method according to claims 1 to 4, characterized by dal the washing liquid repeatedly through the The stove is brought to the tile in one and the same way. 6. The method according to claims 1 to 3, characterized by since the liquid supplied to the digester as washing liquid or returned to it by heat 909811/0978 15171U Exchange with the discharged cooking liquor is heated. 7. The method naoh claims 1 to 6, characterized marked "that the used washing liquid" which is finally discharged from the stove "in one place "which is located upstream of the point at which the repeatedly circulated washing * is sieved off. liquid is withdrawn from the cooker. 8, method according to claim 5, 6 or 7 "characterized" that the circulating washing liquid is driven through the fiber material essentially transversely to its direction of movement coinciding with the direction of movement of the digester, preferably radially outward from an "essential inlet, and at the same time a washing liquid flow is driven in the upstream to the fiber material to an outlet «through which the washing liquid is finally discharged from the digester * 9 * Arrangement for carrying out the washing and XUhler process naoh the claims 1 to 8 in an elongated Cellulose cooher for soling «inet fiber material», that is continuously fed in the direction of the Koohers or is promoted «by boiling with Koohlauge under 9098 11/097 8 _BATH high pressure and high temperature, characterized in that in the digester wall between a liquid inlet, which is arranged in the vicinity of an outlet for the digested pulp, and a sieve belt, which is used to screen the waste liquor from the pulp, another sieve belt is arranged, which is connected to a line which is connected through a heater located outside the cooker and leads back to the cooker, in which it opens between the mentioned liquid inlet and the first-mentioned sieve belt, so that the liquid inlet supplied liquid first cools the fiber material and then this at an elevated temperature washes. ORIG1 _NAL 9098 11/0978