JPH07157991A - Method and apparatus for extracting cooking liquor in continuous cooking - Google Patents

Abstract

(57) [Summary] [Objective] The radial liquid flow from the center of the cooking liquor in the digester to the inner peripheral wall is made uniform, and the quality of the obtained pulp is made uniform. [Structure] An annular strainer 42 having a large number of extraction slits 42a, an annular liquid reservoir 44, an extraction header 45 if necessary, an extraction pipe 47 connected to the liquid reservoir or the extraction header, and a continuous digester A cooking liquor extraction device provided in an intermediate portion, wherein the liquor reservoir is partitioned by a partition plate 5
The flow rate adjusting means 56 controls the flow rate of the cooking liquor in each of the divided liquid storage portions 44a to 44d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking liquor extraction method and apparatus for continuous cooking. More specifically, the present invention is to flow wood chips and a cooking liquor in a continuous digester, and to extract and circulate a part of the cooking liquor to produce pulp, in which the flow distribution of the cooking liquor in the continuous digester and The present invention relates to a method and an apparatus for partially extracting a cooking liquor, which is effective for controlling a temperature distribution and the like to a desired state and stabilizing a cooking degree of a pulp that has been cooked to a desired value.

[0002]

BACKGROUND OF THE INVENTION Conventional engineering methods for producing chemical pulp from lignocellulosic materials such as wood chips are
It is roughly classified into a batch cooking method and a continuous cooking method.

The continuous cooking method is a cooking zone, or a one-bessel vertical type continuous digester having a permeation zone and a cooking zone,
Alternatively, it is carried out using a 2-vessel vertical continuous digester consisting of a vertical continuous infiltration cooker having an infiltration zone and a vertical continuous digester having a cooking zone. In the infiltration zone and cooking zone, the wood chips filled in it are continuously flowed from the top to the bottom while the cooking liquor is made to flow, and a part of this cooking liquor is extracted, which is heated by heating means. The temperature is increased by adding the required amount of cooking chemicals to it, if necessary, and refluxing it to the infiltration zone or cooking zone for circulation, thereby promoting the penetration and cooking of the wood chips by the cooking fluid (circulation. system).

In addition, the cleaning liquid is poured from the bottom of the digester,
By extracting the cooking waste liquor from the middle part of the digester, a wash liquor stream is formed in the lower part of the digester in the counter direction to the descending direction of the wood chips (extraction system). High heat cleaning is applied.

Further, if necessary, a part of the washing and cooking mixture is extracted from the middle portion of the high heat washing zone,
This is heated by a heating means, and if necessary, a cooking chemical liquid is added thereto and refluxed into the digester (circulation system), thereby expanding the digestion zone.
You can also do ntinuous Cooking).

Generally, the main factors that affect the cooking effect are the cooking temperature, the cooking time, the concentration of cooking chemicals, etc. In a continuous digester, in order to control these factors, the circulation system, and An extraction system etc. is provided. In the circulation system, a part of the cooking liquor in the digester is extracted, heated to a desired temperature, and adjusted to a desired cooking chemical concentration. Further, in the extraction system, by replacing a part of the cooking liquor in the lower part of the digester with the washing liquor,
The temperature of the cooking liquor and the concentration of the cooking liquor in this portion can be lowered to control the progress of the cooking, thereby adjusting the cooking time.

As described above, in order to facilitate the progress of the digestion in the continuous digester and produce pulp of constant quality, the wood chips drop in a stable state from the top to the bottom of the digester. That is, in the upper part of the digester, the cooking liquor flows in parallel with the descending direction of the wood chips,
In the lower part of the digester, the cooking liquor and the wash liquor flow countercurrently to the descending direction of the wood chips, and the parallel flow and countercurrent are stable, and the cooking liquor in the digester It is important that the flow distribution of the washing liquid, the temperature distribution, and the like are substantially uniform in a cross section perpendicular to the central axis of the digester (hereinafter referred to as a cross section).

In the conventional continuous cooking method and apparatus,
To separate and extract a portion of the cooking liquor (including wash liquor) from the wood chips, an annular strainer is placed at the desired location between the top and bottom of the digester. This strainer is provided in an annular shape by enclosing the flow paths of the wood chips and the cooking liquor of the digester, and has a large number of extraction holes or slits formed on the entire peripheral surface thereof. The strainer may be provided in a single stage or 2
You may provide so that it may be multi-stage more than a stage. The strainer may be provided with an extraction hole (round hole) or an extraction slit, but generally 2 to 5
A slit having a width of mm is provided substantially parallel to the central axis of the digester. The extraction opening area of the strainer is appropriately designed so that a necessary extraction flow rate can be secured and uneven extraction does not occur. Generally, when the extraction opening area of the strainer is excessively small, the wood chips block the opening to cause clogging, and it becomes impossible to secure a necessary extraction flow rate. Further, if the extraction opening area of the strainer is excessively large, the extraction flow rate distribution in the cross-sectional direction of the digester becomes non-uniform and extraction unevenness is likely to occur.

Between the strainer and the outer wall of the digester,
An annular space called a sump is formed, and the cooking liquor passing through the extraction opening of the strainer flows into this annular sump. The annular liquid reservoir may be directly connected to the extraction pipe, or may be connected to an annular extraction header through a communication port provided at the bottom of the liquid reservoir, and the annular extraction header may be connected to the annular extraction header. The extraction pipe may be connected. That is, the cooking liquor flowing into the annular liquid sump can be directly taken out of the digester by the extraction pipe, or can be taken out of the digester by the extraction pipe through the extraction header.

In the conventional cooking liquor extraction method and apparatus as described above, the flow state and temperature of the cooking liquor in the digester depend on the shape, size, and filling state of the wood chips fed into the digester. The distribution may be non-uniform and the cooking liquor extraction state in the strainer may be non-uniform. Such a non-uniform state makes the progress of the cooking on the wood chips non-uniform and the quality of the obtained pulp to be non-uniform.

[0011]

DISCLOSURE OF THE INVENTION The present invention, in a continuous cooking with a cooking liquor of wood chips in a continuous digester, homogenizes the flow of the cooking liquor in the digester when extracting and circulating a part of the cooking liquor. Thus, it is an object of the present invention to provide a cooking liquor extraction method and apparatus in continuous cooking, which is effective in preventing variations in the quality of the obtained pulp.

[0012]

The method for extracting cooking liquor in continuous cooking according to the present invention comprises: (a) flowing the cooking liquor into the digester while lowering the wood chips from the top to the bottom of the digester. (B) At least one position between the top and the bottom of the digester, the strainer and the digester are passed through a large number of extraction holes or slits of an annular strainer that surrounds the flow path of the wood chips and cooking liquor. A part of the cooking liquor is extracted into an annular liquid pool formed between the liquid and the outer wall, and (c) the extracted cooking liquor part is removed from the liquid pool to the outside of the digester. The liquid sump is partitioned into two or more parts in parallel with the central axis direction of the digester, and the cooking liquid parts extracted into each of the partitioned liquid sump parts are provided in the respective liquid sump parts. It is characterized in that the flow rate of the cooking liquor portion extracted from the digester to the outside of the digester through the above extraction port and extracted from the digester to the outside is controlled to a desired value. It is what

Another method for extracting a cooking liquor in continuous cooking according to the present invention is: (a) flowing the cooking liquor into the digester while lowering the wood chips from the top to the bottom of the digester; Between the strainer and the outer wall of the digester at least at an intermediate position between the top and the bottom of the digester, through a number of extraction holes or slits of an annular strainer that surrounds the flow path of the wood chips and cooking liquor. A part of the cooking liquor is extracted into the annular liquor pool formed in, and (c) the extracted cooking liquor is connected to the wood chips and the flow path of the cooking liquor and communicated with the bottom of the liquor pool. And discharging the digested liquor portion that has flowed out from the extraction header to the outside of the digester. Each of the dars is partitioned into two or more parts in parallel with the central axis of the digester, and the cooking liquor part extracted into each of the partitioned liquor reservoirs is provided at the bottom of the liquor reservoir. 1 through at least one communication port to the partitioned extraction header portion, and the lowered cooking liquor portion is provided to each extraction header portion.
Characterized in that the flow rate of the cooking liquor extracted from the digester outside the digester through the above-mentioned extraction port and extracted to the outside of the digester for each of the partitioned liquid storage portions is controlled to a desired value. Is.

The cooking liquor extraction device of the continuous digester of the present invention is
A cooking liquor extraction device provided in at least one location between the top and the bottom of a digester having a top having wood chips and a cooking liquor inlet and a bottom having an outlet for cooked pulp and cooking effluent Which is (a) a strainer that includes a flow path for the wood chips and the cooking liquor and has a large number of extraction holes or slits; and (b) a liquid formed between the strainer and the outer wall of the digester. A sump and (c) an extraction pipe connected to the sump, and the sump is divided into two or more parts by a partition plate parallel to the central axis direction of the digester. One extraction pipe is connected to each of the partitioned liquid reservoirs through one or more extraction ports, and the extraction pipe is provided with a flow rate control means for controlling the flow rate of the cooking liquor passing therethrough. And it is characterized in that is.

Another digester cooking liquor extractor of the invention is a digester having a top having wood chips and a cooking liquor inlet, and a bottom having cooked pulp and cooking effluent outlets. A cooking liquor extraction device provided at at least one position intermediate between and, (a) a strainer that includes a flow path for the wood chips and the cooking liquor, and has a large number of extraction holes or slits;
A sump formed between the strainer and the outer wall of the digester; (c) an extraction header in communication with the sump and containing a flow path for the wood chips and cooking liquor; ) An extraction pipe connected to the extraction header, wherein each of the liquid reservoir and the extraction header is formed by a partition plate parallel to the central axis direction of the digester,
The partition is divided into two or more parts, and the bottom of the partitioned liquid reservoir part communicates with the partitioned extraction header part through at least one communication port, and the partitioned extraction header part 1 for each via one or more extraction ports
Book extraction pipe is connected, to the extraction pipe,
It is characterized in that a flow rate control means for controlling the flow rate of the cooking liquor passing therethrough is attached.

In the present invention, unless otherwise specified, the cooking liquor includes all liquids fed into the digester, flowing therein, and extracted therefrom. That is, cooking liquor includes cooking liquor, washing liquor, and mixtures thereof.

[0017]

An example of a continuous cooking method and apparatus for wood chips will be described with reference to FIG. The vertical continuous digester 1 shown in FIG. 1 is a tower-shaped body composed of a top portion 2, a bottom portion 3 and an intermediate portion 4, and the top portion 2 is provided with an inlet 5 for wood chips and cooking liquor. The bottom part 3 is provided with a discharge port 6 for pulp and cooking waste liquid.

In FIG. 1, a discharge means 6a having a one-stage strainer for discharging an overflow of cooking liquor is arranged on the digester top 2, and a discharge pipe 7 is connected to the discharge means 6a. There is. Further, a cleaning liquid feeding pipe 8 is connected and inserted into the bottom portion 3 so that the cleaning liquid can be fed upward into the digester 1 as shown in the drawing.

In FIG. 1, in the middle section 4 of the digester 1,
First, second, third, fourth cooking liquor extraction means 9, 10, 11, and 12 having two-stage strainers are provided.
The middle part between the discharge means 6 and the extraction means 9 of the digester 1 is the chemical liquid permeation zone 13 at a relatively low temperature (for example, 120 ° C.), and the middle part between the extraction means 9 and the extraction means 10 is at a relatively high temperature (for example, 165 ° C.) upper cooking zone 14, the middle part between the extraction means 10 and the extraction means 11 is a (MCC) cooking zone 15 at a relatively high temperature (for example, 165 ° C.), and the extraction means 11 and the extraction means 12 are The middle part is the high heat cleaning zone 16 at a relatively low temperature (for example, 130 ° C.). In the chemical liquid infiltration zone 13 and the upper cooking zone 14, the cooking liquid flows downward as shown, but in the (MCC) cooking zone 15 and the high heat cleaning zone 16, the cooking liquid flows upward from the cleaning liquid inlet pipe. The supplied cleaning liquid causes the cooking liquid (including the cleaning liquid) in the zone to flow almost upward as shown in the drawing.

The cooking liquor extracted from the first extracting means 9 is
After passing through the extraction pipes 17, 18, 19 and the circulation pump 20, it is fed into the heater 21, where it is heated to a desired temperature. Further, if necessary, a cooking chemical liquid is added to the extracted cooking liquid in the extraction pipe 19. The heated cooking liquor is adjusted to a predetermined flow rate by the flow rate adjusting means 22, and is sent to the lower central portion of the chemical liquid permeation zone 13 through the circulation pipe 23 inserted into the chemical liquid permeation zone 13.
An on-off valve may be attached to the extraction pipes 17 and 18 as shown in the figure.

The cooking liquor extracted from the second extracting means 10 is discharged to the outside of the digester as cooking waste liquid through the extraction pipes 24, 25 and 26. An open / close valve may be attached to each of the pipes 24 and 25 as shown in the drawing.

The cooking liquor extracted from the third extracting means 11 is extracted pipes 27, 28, 29 and the circulation pump 3.
After passing 0, it is fed into the heater 31, where it is heated to a predetermined temperature. The heated cooking liquor is fed to the lower central portion of the (MCC) cooking zone 15 by the flow rate adjusting means 32 at a desired flow rate through the circulation pipe 33 inserted into the (MCC) cooking zone 15. . If necessary, a cooking chemical liquid is added to the cooking liquid in the pipe 29. An open / close valve may be attached to the extraction pipes 27 and 28 as shown in the drawing.

The cooking liquor extracted from the fourth extraction means 12 is extracted pipes 34, 35, 36 and the circulation pump 3.
It is fed into the heater 38 via 7 and heated there to a desired temperature. If necessary, a cooking chemical liquid is added to the extracted cooking liquid in the extraction pipe 36. Next, the cooking liquor sent from the heater 38 is adjusted to a desired flow rate by the flow rate adjusting means 39, and the high heat cleaning zone 1
It is sent to the lower central part in the high-heat cleaning zone through the circulation pipe 40 inserted in 6.

An example of the constitution of the cooking liquor extraction means is shown in FIG.
It shows in (A) and FIG. 2- (B). 2- (A) and (B), the extraction means 41 is the inner wall surface 41 of the digester.
It has an annular strainer 42 arranged along a and having a large number of extraction slits 42 a, a digester outer wall 43, and an annular liquid reservoir 44 formed between the strainer 42. An annular extraction header 45 may be provided below the liquid reservoir 44, and in this case, the bottom of the liquid reservoir 44 communicates with the extraction header 45 by a plurality of communication holes 46 that are separated from each other. There is.

Although the sump 44 may be directly connected to the extraction pipe, as shown, the extraction header 45 may be connected to the extraction pipe 47, which is a ring pipe. It may be connected to 48.

The extraction slit is usually formed parallel to the central axis of the digester, but is not limited to this. Further, instead of the slit, an extraction hole (for example, a circular hole) may be used.
The extraction slit has a width of 3 to 5 mm and a pitch of 10 to 20.
mm and a height of 100 to 200 mm are preferable. The annular strainer may be formed in a single step, or
It may be configured to have two or more layers stacked vertically.

In the conventional extraction means, since the liquid reservoir is not partitioned into two or more parts by the partition plate parallel to the central axis of the digester, the extracted cooking liquor is removed from the digester outside the digester at any arbitrary part. Can be taken out. However, it is impossible to uniformly control the liquid amount distribution of the cooking liquor flowing into the liquid reservoir through the extraction slit.

For example, in the conventional cooking liquor extraction device, as shown in FIG. 3, an annular strainer 42 is arranged inside an outer wall 43 of the digester, and between the outer wall 43 of the digester and the annular strainer 42. A ring-shaped liquid reservoir 44 with no partition
Are formed. Directly in this liquid reservoir 44, or
One or more, for example two extraction pipes 47 as shown, are connected via an undivided extraction header (not shown), which two circulation pipes 47 circulate via a ring pipe 48. It is connected to the pipe 49. The opening / closing valve 50 may be attached to the extraction pipe or the ring pipe. A circulation pump 51, a heater 52, and a flow rate adjusting means 53 are arranged in the circulation pipe 49 system, and the cooking liquor flow adjusted to a predetermined temperature and a predetermined flow rate is inserted into a substantially central portion of the digester. It is circulated into the digester from the end of the central circulation pipe.

In such a conventional cooking liquor extraction device, the total flow rate of the cooking liquor to be extracted, circulated and fed is adjusted to a desired value, but the cooking liquor flowing in the digester is controlled by an annular strainer. Through the extraction slit, it is not possible to flow out to the liquid reservoir with a substantially uniform extraction amount distribution. In this way, the fact that the extraction amount distribution in the liquid sump is non-uniform means that the flow rate distribution of the liquid flow radially flowing from the central part toward the strainer in the digester is non-uniform. However, such non-uniformity of the cooking liquor flow naturally causes variations in the cooking temperature distribution and the cooking chemical concentration distribution, and eventually in the cooking degree of the obtained pulp.

An embodiment of the cooking liquor extraction method and apparatus of the present invention is shown in FIG. In FIG. 4, an annular strainer 42 is arranged inside the digester outer wall 43,
An annular liquid reservoir 44 is formed between the outer wall 43 of the digester and the annular strainer 42. The annular liquid reservoir 44 is divided into four parts 44a, 44b, 44c, 4 by four partition plates 55 parallel to the central axis (not shown) of the digester.
It is divided into 4d. Below this annular liquid reservoir 44,
An annular extraction header (not shown) may be formed, in which case the annular extraction header will be divided into four by four partition plates (not shown) as above.
It is divided into individual parts.

Liquid reservoir portion 44a partitioned as described above
To d are connected to the ring pipes 48a, b, c, or d via one or more (three in FIG. 4) extraction pipes 47, and each of the ring pipes 48a to 48d has a flow rate adjustment function. Means 56a-d are attached. The ring pipes 48a and 48b are connected to the main circulation pipe 58 via the circulation pipe 57, and the other ring pipes 48c and 48d are connected to the main circulation pipe 58 via the circulation pipe 59. A circulation pump 51 and a heater 52 are attached to the main circulation pipe 58, the cooking liquor passing through the main circulation pipe 58 is heated to a predetermined temperature, and a central circulation pipe 54 is inserted into the center of the digester 1. It is fed into the digester from the end. When a partitioned extraction header is provided below the partitioned sump, the extraction pipe 47 is connected to each part of the partitioned extraction header.

The number of partitions of the liquid reservoir may be two or more, and may be four as shown in FIG. 4 or may be more. The number of partitions of the extraction header is the same as above. The number of extraction pipes communicating with each of the partitioned liquid storage portions may be one or more,
It is preferably two or more, for example three as shown in FIG.

The flow rate adjusting means used in the present invention is provided for each of the partitioned liquid storage portions. Therefore, the flow rate of the cooking liquor flowing into each of the liquid storage portions is controlled to a desired value. In this way, by controlling the inflow rate of the cooking liquor for each of the partitioned sump portions, the flow rate of the radial liquor toward the strainer from the center of the digester can be changed with respect to the filled wood chips. It becomes possible to control so that a substantially uniform cooking can be performed.

In general, the flow rates of the cooking liquors extracted in each of the partitioned liquid storage parts are controlled to be the same. When the strainer is clogged by the continuous extraction operation, the extraction operation of the strainer is interrupted and paused at a predetermined cycle, in which case a constant extraction amount is obtained during the extraction operation period. So that
Adjust the flow rate. In addition, even if the flow rate is adjusted to a constant value, if the temperature distribution and cooking chemical liquid distribution in the digester vary, install a thermometer or chemical concentration meter in the extraction pipe system,
The flow rate is adjusted so that the temperature or chemical concentration of the extracted cooking liquor becomes a desired value.

In the present invention, the effect of adjusting the flow rate applied to each of the partitioned liquid storage portions is that the cooking liquid flow and the downward flow of the wood chips form a parallel flow like the chemical liquid infiltration zone and the upper cooking zone. It is also sufficiently expressed in the eggplant zone, but it is particularly prominent in the zone where the cooking liquor flow and the downflow of wood chips are countercurrent flows, such as the (MCC) cooking zone and the high heat washing zone. It

The flow rate adjusting means used in the present invention is not particularly limited, but for example, as shown in FIG. 4, it has a flow rate adjusting valve 60, a flow meter 61, and a controller 62, and has a circulation pipe. Measure the flow rate of cooking liquor passing through
1, and the detected data is detected by the controller 6
2, the detected data may be compared with a desired flow rate value stored in advance, and the flow rate through the flow rate control valve 60 may be adjusted according to the comparison result. .

[0037]

EFFECT OF THE INVENTION A liquid sump for extracting a cooking liquor in a digester and, if necessary, an extraction header is further divided into two or more parts, and the extraction flow rate is controlled to a desired value by a flow rate adjusting means provided for each of them. By this 1. In the extraction system, the cooking waste liquid can be uniformly discharged from the inner peripheral surface of the kettle. 2. In the circulation system, the cooking can be uniformly extracted from the inner peripheral surface of the kettle, and the radial liquid flow of the cooking liquid fed from the central circulation pipe can be made uniform toward the inner peripheral surface of the digester. By the above effect, the cooking temperature and the chemical concentration are stable, the variation in the degree of cooking is extremely small, and the strength of the pulp is improved and the pulp quality is improved and the yield is improved due to the decrease of undigested materials and the decrease of over-dissolved materials. It is possible and costs are reduced.

[Brief description of drawings]

FIG. 1 is a front explanatory view showing the structure of a continuous digester.

FIG. 2 (A) is a side cross-sectional explanatory view of an example of cooking liquor extraction means, and FIG. 2 (B) is a part of the cooking liquor extraction means shown in FIG. 2 (A). Front development view.

FIG. 3 is a cross-sectional explanatory view showing a configuration of an example of a conventional cooking liquor extraction device.

FIG. 4 is an explanatory cross-sectional view showing the configuration of an embodiment of the cooking liquor extraction device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Continuous digester 2 ... Top 3 ... Bottom 4 ... Middle part 5 ... Wood chip, cooking liquid inlet 6 ... Pulp cooking waste liquid discharge port 6a ... Discharge means 7 ... Discharge pipe 8 ... Wash liquid supply pipe 9,10,11 , 12 ... Cooking liquid extraction means 13 ... Chemical liquid permeation zone 14 ... Upper cooking zone 15 ... (MCC) cooking zone 16 ... High heat washing zone 17, 18, 19, 24, 25, 26, 27, 28, 2
9, 34, 35, 36 ... Extraction pipe 20, 30, 37 ... Circulation pump 21, 31, 38 ... Heater 22, 32, 39 ... Flow rate adjusting means 23, 33, 40 ... Circulation pipe 41 ... Cooking liquor extraction means 41a ... Inside wall 42a of digester ... Extraction slit 42 ... Annular strainer 43 ... Outer wall of digester 44 ... Reservoir 45 ... Extraction header 46 ... Communication hole 47 ... Extraction pipe 48 ... Ring pipe 49 ... Circulation pipe 50 ... Open / close valves 51, 57, 59 ... Circulation pipe 52 ... Heater 53, 56a-56d ... Flow rate adjusting means 54 ... Central circulation pipe 55 ... Partition plate 58 ... Main circulation pipe 60 ... Flow control valve 61 ... Flow meter 62 ... Controller

Claims (4)

[Claims] 1. A cooking fluid is flowed into the digester while (a) lowering wood chips from the top to the bottom of the digester, and (b) between the top and bottom of the digester. At least at one location, through the numerous extraction holes or slits of the annular strainer that surrounds the flow path of the wood chips and cooking liquor, into the annular liquor reservoir formed between the strainer and the outer wall of the digester, the cooking Extracting a portion of the liquor, and (c) removing the extracted cooking liquor portion from the liquor to the outside of the digester, the liquor being parallel to the central axis of the digester, Partition into the above parts, and extract the cooking liquor part extracted into each of the partitioned liquor storage parts, through one or more extraction ports provided in each liquor storage part, and take it out of the digester. And the above For each of cut the liquid reservoir portion, then the flow rate of the cooking liquor portion to be extracted outside the digester and controls the desired value. Extraction method of cooking liquor in continuous cooking. 2. (a) Flowing the cooking liquor into the digester while lowering the wood chips from the top to the bottom of the digester, and (b) at least the middle of the top and bottom of the digester. At one location, the cooking liquor is placed in an annular liquor reservoir formed between the strainer and the outer wall of the digester through a number of extraction holes or slits in the annular strainer that encloses the wood chip and cooking liquor flow paths. And (c) allowing the extracted cooking liquor to flow into an annular extraction header which encloses the wood chip and cooking liquor flow paths and communicates with the bottom of the sump, and (d) ) A step of taking out the discharged cooking liquor portion from the extraction header to the outside of the digester, wherein each of the liquid reservoir and the extraction header is parallel to the central axis of the digester. , A partition into two or more parts, and the digested liquor part extracted into each of the partitioned liquor reservoir parts is separated through the at least one communication port provided at the bottom of the liquor reservoir part into the partitioned extraction header part. To
The lowered cooking liquor portion is taken out of the digester via one or more extraction ports provided in each extraction header portion, and for each of the partitioned liquor portions, it is extracted from the digester outside of it. A method for extracting a cooking liquor in continuous cooking, which comprises controlling the flow rate of the cooking liquor to a desired value. 3. A digester provided with a top having a wood chip and a cooking liquor inlet, and a bottom having a digested pulp and a cooking effluent outlet, provided at least at one position between the top and the bottom. A cooking liquor extraction device comprising: (a) a strainer that includes a flow path for the wood chips and the cooking liquor and has a large number of extraction holes or slits; and (b) a strainer between the strainer and the outer wall of the digester. It has a formed liquid reservoir and (c) an extraction pipe connected to this liquid reservoir, and the liquid reservoir is partitioned into two or more parts by a partition plate parallel to the central axis direction of the digester. Each of these partitioned reservoirs has one or more extraction ports
Book extraction pipe is connected, to the extraction pipe,
A cooking liquor extraction device for a continuous digester, which is equipped with a flow rate control means for controlling the flow rate of the cooking liquor passing therethrough. 4. A digester provided with a top having a wood chip and a cooking liquor inlet, and a bottom having a digested pulp and a cooking effluent outlet, provided at least at one position between the top and the bottom. A cooking liquor extraction device comprising: (a) a strainer that includes a flow path for the wood chips and the cooking liquor and has a large number of extraction holes or slits; and (b) a strainer between the strainer and the outer wall of the digester. The formed sump, (c) an extraction header which communicates with this sump, and which encloses the flow path of the wood chips and the cooking liquor, and (d) an extraction pipe connected to the extraction header. Each of the liquid reservoir and the extraction header is partitioned into two or more parts by a partition plate parallel to the central axis direction of the digester, and the partitioned liquid reservoir part Bottom, 1
One or more extraction pipes are connected to each of the partitioned extraction header parts via one or more communication ports, and one extraction pipe is connected to each of the partitioned extraction header parts via one or more extraction ports. And a flow control means for controlling a flow rate of the cooking liquor passing through the extraction pipe.