WO2000073573A1 - Process for digesting lignocellulose material - Google Patents

Abstract

A continuous process for digesting a lignocellulose material using a one-vessel digestion apparatus, wherein a digester has, from the top towards the bottom thereof, an overhead zone, an upper digestion zone and a lower digestion zone, each zone has a strainer at its bottom, and a black digestion liquor extracted is discharged from at least one strainer to the outside of the digestion system, characterized in that use is made of a chip from a broad-leaved tree or a needle-leaved tree; an alkaline digestion liquid is added at the top of the digester which liquid contains a polysulfide type sulfur in a concentration of 3 to 20 g/L as sulfur, and contains sulfur in an amount of 45 to 100 wt. % and an effective alkali in an amount of 45 to 79 wt. %, both percentages being relative to the respective total amounts contained in the alkaline digestion liquid introduced to the above digestion system; an alkaline digestion liquid containing 0.01 to 105 wt. % of a quinone compound relative to an absolutely dried chip is fed to the digester. The process can be employed for lowering the kappa value for the same percentage of addition of an effective alkali and also for improving the yield of pulp for the same kappa value.

Description

 Description Cooking process for lignocellulosic materials

 The present invention relates to a method for cooking lignocellulosic material, and more specifically, can further improve pulp yield and further improve the relationship between monovalent kappa and pulp yield compared to conventional cooking methods. The present invention also relates to a method for digesting lignocellulosic material capable of reducing the pulp value at the same effective alkali addition rate and improving the pulp yield at the same power value. Background art

 The main method of chemical pulp production that has been carried out industrially so far is the alkaline digestion of lignocellulosic materials such as wood chips, of which sodium hydroxide and sodium sulfide are the main components. The craft method using refining liquor is widely used. Conventionally, as a method for improving the pulp yield, a cooking aid comprising a quinone compound, which is a cyclic keto compound such as anthraquinone sulfonate and anthraquinone non-tetrahydroanthraquinone, is used as a cooking aid. (For example, Japanese Patent Publication No. 55-13998, Japanese Patent Publication No. 57-19239, Japanese Patent Publication No. 53-45404, Japanese Unexamined Patent Application Publication No. No. 52-73783). The quinone compound improves the selectivity of delignification, and contributes to the reduction of monovalent kappa of cooked pulp and the improvement of yield.

The polysulfide cooking method, in which cooking is carried out using an alkaline cooking liquor containing polysulfide, is also a very effective method for improving the yield. Polysulfide oxidizes the carbonyl terminus of carbohydrates and contributes to yield improvement by suppressing carbohydrate decomposition by peeling reaction. The alkaline cooking liquor containing polysulfide is produced by oxidizing an alkaline solution containing sodium sulfide with molecular oxygen such as air in the presence of a catalyst such as activated carbon. (For example, Japanese Patent Publication No. 50-43095, Japanese Patent Application Laid-Open No. 61-257,38, Japanese Patent Application Laid-Open No. 61-259,754, Japanese Patent Application No. 583844). According to this method, polysulfides with a conversion of about 60% and a selectivity of about 60% on the basis of sulfide ions and a polysulfide concentration of about 5 gZL (L represents little. The same applies in this specification) A strong cooking liquor can be obtained. However, in this method, thiosulfate, which does not contribute to the digestion at all, is produced as a by-product, so that it is not possible to produce an alkaline cooking liquor containing a high concentration of polysulfide sulfur at a high selectivity. It was difficult.

 On the other hand, PCT International Publication Nos. WO9500701 and WO97Z0771 describe an electrolytic production method of an alkaline cooking liquor containing polysulfide. This method can produce an alkaline cooking liquor containing a high concentration of polysulfide sulfur at a high selectivity with extremely little by-product of thiosulfate. Another method for obtaining an alkaline cooking liquor containing high-concentration polysulfide sulfur is to dissolve molecular sulfur in an alkaline aqueous solution containing sodium sulfide. Japanese Patent Application Laid-Open No. 7-189153 discloses a cooking method in which a cooking quinone compound is used in combination with an alkaline cooking liquor containing polysulfide. The official gazette discloses the mitigation of the decomposition of polysulfide by quinone compounds under hot alkaline conditions.

By the way, in recent years, pulp strength, which is a problem in the craft method, has been improved. Generally, this is called the modified craft method (hereinafter referred to as the MCC method). Was presented. The MCC method differs from the conventional craft method in that the cooking liquor is divided and added to the upper cooking zone at the beginning of cooking and after the cooking temperature reaches the maximum temperature. There is a feature in performing. Countercurrent refers to the case where the cooking liquid flows from the bottom to the top of the kettle. However, although the pulp strength is improved and the kappa value is reduced in the MCC method, there are problems such as an increase in cooking temperature and an increase in cooking chemicals per lignocellulosic material. This did not lead to an increase in pulp yield.

 Attempts have been made to add a cyclic ketone compound as a cooking aid to the MCC method, which has the characteristic of having a place to add a cooking liquor to the beginning of a digestion and to a predetermined cooking zone. No. 184, Japanese Unexamined Patent Application Publication No. Hei 4-20983, Japanese Unexamined Patent Application Publication No. Hei 4-208, Japanese Unexamined Patent Application Publication No. Japanese Patent Publication No. 0 98866 discloses a two-vessel type continuous digester. In Japanese Patent Application Laid-Open No. HEI 4-119883, when a cyclic keto compound is added to the MCC digestion liquor, in Japanese Patent Application Laid-Open No. 4-209883, the cyclic keto compound is digested. In the case where the cyclic keto compound is added to the upper digestion zone or the like in Japanese Unexamined Patent Application Publication No. 4-20984 / 1992, when it is added at the beginning (permeation vessel), it is disclosed in Japanese Unexamined Patent Application Publication No. 4-209895 / 1992. Discloses a case where a cyclic keto compound is added to a lower cooking zone, and Japanese Patent Application Laid-Open No. 4-209886 discloses a case where a cyclic keto compound is added to an upper cooking zone and a lower cooking zone at the beginning of cooking. However, there is no description of the difference in effect between the respective addition methods, and it is unclear about the more effective addition method of the quinone compound, which is a cyclic keto compound, in polysulfide cooking. .

Recently, an improvement method called the Lo-Solids (registered trademark) method was proposed to solve the problems of the MCC method. In this method, in order to minimize the concentration of dissolved organic solids in most parts of the digester where delignification takes place, extraction of the cooking black liquor is performed at several points in the digester. After the cooking temperature reaches the maximum temperature, the cooking liquor is divided and added to the cooking zone, and co-current and counter-current cooking are performed inside the digester. Since the cooking liquor is also added at the bottom of the digester, cooking is also performed at the bottom of the digester, resulting in slower cooking at a lower temperature than in the past, and a longer processing time in the entire cooking zone. Become. In addition, above the upper digestion zone, which is a countercurrent digestion, ie, at the bottom of the extraction strainer at the bottom of the tower top zone, or at the bottom of the lower digestion zone, which is a cocurrent digestion, that is, above the digestion washing zone which is a countercurrent digestion. Most of the cooking black liquor was extracted from the extraction strainer, keeping the organic solids concentration in the digester low. It is.

 Cooking chemicals (chemicals for cooking) are also consumed by organic substances eluted from the lignocellulosic material in addition to delignification elution reaction of the lignocellulose material.

. In the L 0—S 0 1 ids (trademark) method, digestion black liquor containing organic matter is extracted from several places in the digester, and the digester is supplied not only at the beginning of the digestion but also during the digestion. It reduces the concentration of dissolved organic matter mainly composed of lignin in the inner black liquor, suppresses the consumption of cooking chemicals by this dissolved organic matter, and improves the selectivity of delignification during cooking. As a result, improvements in pulp strength and reduction in cooking chemicals used were achieved.

 Where is power? In the L 0—S 0 1 ids (registered trademark) method in a 1-vessel digester, a considerable amount of black liquor is extracted during the course of the polysulfide digestion by adding a quinone compound. As a result, quinone compounds, which are expensive cooking aids, are also discharged out of the digestion system, further reducing cooking chemicals, improving pulp yield, and examining the relationship between kappa monovalent and pulp yield. There was a problem in terms of improvement.

 Therefore, the present invention solves the above-mentioned problems, and in one vessel digester, extracts cooking black liquor from a plurality of locations of the digester, and adds an alkaline cooking liquor to a predetermined digestion zone at the top of the digester. The present invention is to provide a lignocellulosic material digestion method capable of performing polysulfide digestion that contributes to an increase in yield and using a quinone compound as a cooking aid more effectively. Aim.

Further, the present invention is to provide an improved method for further improving pulp yield, further improving the relationship between kappa monovalent value and pulp yield, and reducing the amount of chemicals required for cooking and bleaching. is there. That is, an object of the present invention is to reduce the pulp monovalent at the same effective power addition rate and improve the pulp yield at the same effective monovalent valency. Disclosure of the invention The present invention includes a top zone, an upper digestion zone, and a lower digestion zone from the top to the bottom inside the digester, wherein a strainer is provided at the bottom of each zone, and among the strainers, In a continuous digestion method using a 1-vessel digester in which the black liquor extracted from at least one strainer is discharged out of the digester, using hardwood or softwood chips, the sulfur content is 3 to It contains polysulfated sulfur at a concentration of 20 g ZL, and contains 45 to 100% by weight based on the total digestion-active sulfur and the total alcohol contained in the alkaline cooking liquor introduced into the digestion system. is added sulfur and 4 5-7 9 weight ⁰ / alkaline properties cooking liquor comprising an effective Al force Li ₀ is the digester top, further Ze'inuichi Tsu per flop 0.0 1 to 1.5 Alkaline cooking liquor containing quinone compound by weight Providing cooking method of re Diagnostics cellulosic material and supplying to said digester. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a diagram showing an embodiment of a one-vessel continuous digester suitably used in the present invention.

 A tower top zone, B upper digestion zone, C lower digestion zone D digestion washing zone, 1 wood chip, 2 digester, 3 alkaline cooking liquor supply pipe containing polysulfide, 4 upper extraction strainer, 5, 7 Strainer, 6 Lower extraction strainer, 8 Upper alkaline cooking liquor supply pipe, 9 Lower alkaline cooking liquor supply pipe, 10 and 11 Black liquor discharge conduit, 12 Cooking pulp discharge conduit, 13 Washing Liquid introduction pipe, 14 and 15 heater, 16 and 16 'quinone compound introduction pipe, 17 and 18 extraction conduit, 19 upper digestion circulation liquid conduit, 20 lower digestion circulation liquid conduit Best form for

The present invention includes a top zone, an upper digestion zone, and a lower digestion zone from the top to the bottom inside the digester, and a strainer at the bottom of each zone. This is a continuous digestion method using a 1-vessel digester in which cooking black liquor extracted from at least one of the strainers is discharged out of the digestion system. Although not required here, the black liquor discharged outside the digestion system may be extracted from a strainer installed at the bottom of the tower top zone. Similarly, although not essential here, it is preferable to arrange a digestion washing zone below the lower digestion zone.

Then, in the present invention, an alkaline cooking liquor having a different composition is added from the top of the digester, the bottom of the upper digestion zone, and other places. Examples of the alkaline cooking liquor used in the present invention include a solution mainly composed of polysulfide and sodium hydroxide, a solution mainly composed of sodium hydroxide and sodium sulfide, Alternatively, a solution or the like containing sodium hydroxide as a main component is used. The total amount of chemicals contained in the alkaline cooking liquor introduced into the digestion system from each location is 10 to 25% by weight of effective alkali (N a with respect to the absolutely dry chips supplied to the digester). ₂₀ % by weight) and 1 to 10% by weight of sulfur (% by weight of sulfur based on the absolutely dry chips supplied to the digester).

 In the present invention, as the first cooking liquor, an alkaline solution containing polysulfide sulfur at a concentration of 3 to 20 gL as sulfur is supplied to the top of the digester, and the concentration of the polysulfide sulfur is supplied to the digester. More preferably, it is 8 to 18 g ZL. Polysulfide contributes to increased yield by carbohydrate protection, but lacks stability at high temperatures (over 120 ° C) and decomposes at the highest cooking temperature with consumption of sodium hydroxide. In the one-vessel digester of the present invention, when the alkaline cooking liquor containing polysulphide is added in portions during the digestion, the polysulphide is immediately heated to a high temperature if supplied during the digestion. Exposure to water causes decomposition, and the effect of improving the yield cannot be obtained sufficiently.

Therefore, in the present invention, it is necessary that polysulfide is added to the top of the digester before the digestion reaches the maximum temperature, and the polysulfide is allowed to penetrate and react with the chips. Polysulfide sulfur concentration has the effect of improving yield It is added as an alkaline solution containing polysulfide sulfur at a concentration in the above-mentioned range necessary for the above, that is, 3 to 20 g / L as sulfur. If the concentration of polysulfide sulfur in the first cooking liquor is less than 3 g / L, there is almost no contribution to increase in yield, and if it exceeds 20 gZL, it cannot contribute to the carbohydrate protection reaction and many polysulfides remaining As the digestion reaches the maximum temperature, it undergoes decomposition while consuming sodium hydroxide necessary for the digestion, making it impossible to secure the alkali content required for the digestion. The strength value will also be very high.

 The alkaline cooking liquor containing polysulfide used in the present invention can be obtained by a conventional air oxidation method, but a side reaction in which a part of the polysulfide is converted to sodium thiosulfate due to the air oxidation of polysulfide. Therefore, sulfides in a solution containing sulfide ions such as sodium hydroxide and sodium sulfide or sodium carbonate and sodium sulfide as the main components are preferred. It is produced by a method of electrochemically oxidizing ions, ie, an electrolytic method.

 As the electrolysis method used in the present invention, preferably, the following electrolysis method can be applied [(A) Japanese Patent Application No. 10-166374, (B) Japanese Patent Application No. 11-5101. No. 6, (C) Japanese Patent Application No. 11-51 033]. These were previously developed by the present inventors and others, and regarding the electrolysis method, the configuration of the anode, the conditions for disposing the anode in the anode chamber, the pressure conditions between the power source chamber and the anode chamber, and other various requirements It pursued and researched on, and found important requirements for obtaining an effective effect, such as extremely reducing the by-product of thiosulfate ion.

Here, the polysulfide sulfur (PS—S) refers to, for example, sulfur having a valence of 0 in polysulfide sodium Na ₂ S, that is, sulfur for (X—1) atoms. In this specification, the term “sulfur” (S or Na ₂ S equivalent to one atom of sulfur) corresponding to sulfur having an oxidation number of 2 in polysulfide ions (polysulfide) and sulfide ions (S ² ) are collectively referred to in this specification. It will be expressed as suitable Yichun N a ₂ S state sulfur at medium. In this respect, polysulfide Means a combination of the Porisarufuai Dosarufa and N a ₂ S state sulfur and, N a ₂ S state sulfur and sulfide Na Application Benefits um (N a ₂ S) and N a ₂ S x sac Chi N a means minute of ₂ S, also, the cooking sulfur-content of the contributing sulfur content in the digestion reaction, refers to the even combination of the Porisarufuai Dosarufu § and N a ₂ S state sulfur.

(A) The technology of Japanese Patent Application No. 10-16663374 is a three-dimensional physically continuous surface made of a nickel alloy containing at least 50% by weight of nickel or nickel. of having a network structure, and anodic arranging the porous Ano de is the unit surface area to volume of those Rino § Roh one de anode chamber 5 0 0~ 2 0 0 0 0 m 2 / m 3 A solution containing sulfide ion is introduced into the anode chamber of an electrolytic cell having a diaphragm, which separates the anode chamber and the cathode chamber from each other. This is a method for producing polysulfide, characterized in that polysulfide ions are obtained more. According to this method, it is possible to produce a cooking liquor containing a high concentration of polysulfide sulfur while maintaining a high selectivity with extremely low by-products of thiosulfate, and to obtain the polysulfide cooking obtained in this manner. Pulp yield can be effectively increased by using the liquor for cooking. Also, unlike an aggregate of fibers, the anode is a physically continuous network structure, which can lower the cell voltage, thereby reducing operating costs. Furthermore, since the anode used in this technique has good electrical conductivity, it is possible to increase the porosity of the anode and reduce the pressure loss

(B) The technology of Japanese Patent Application No. 11-151,016 is based on the use of an anode chamber for distributing a porous anode, a power source chamber for distributing a power source, and an anode chamber. A method for producing a polysulfide, in which a solution containing sulfide is introduced into an anode chamber of an electrolytic cell having a diaphragm that divides a source chamber, and a polysulfide diode is obtained by electrolytic oxidation. This is a method for producing polysulfide, characterized in that the pressure in the cathode chamber is higher than the pressure in the anode chamber. According to this method, thiosulfur Byproduct is very little acid Ion includes a high concentration of Porisarufuai Dosarufu §, residual N a ₂ S while the state Iou-rich cooking liquor to maintain a high selectivity can be produced at low power, especially pulp manufacturing process The pulp yield can be effectively increased by using the polysulphide cooking liquor thus obtained from the white liquor or green liquor for cooking.

 In this technology, the electrolysis operation is performed under conditions where the pressure in the force source chamber is greater than the pressure in the anode chamber. The electrolytic cell generally has a structure in which a diaphragm is sandwiched between an anode and a cathode. From the viewpoints of assembly accuracy and protection of the diaphragm, the anode and the cathode are arranged at a relatively large distance. More specifically, a distance of about several millimeters is often available. The diaphragm disposed between them approaches the anode side or approaches the cathode side depending on the electrolysis conditions. In this technology, the diaphragm is forced into constant contact with the anode, there is no space between the anode and the diaphragm, and the anolyte is entirely introduced into the porous anode. Thus, current efficiency and the like are improved. For this purpose, electrolysis is performed under conditions where the pressure in the force chamber is higher than the pressure in the anode chamber. By doing so, since the diaphragm is pressed against the anode, the anode solution can be sufficiently flowed inside the porous anode, and a high selectivity is realized. In this technique, as a means for increasing the pressure in the cathode chamber higher than the pressure in the anode chamber, the flow rate of the solution (power source liquid) introduced into the force chamber is controlled by the flow rate of the solution. There is a method of increasing the flow resistance of the solution to be introduced into the furnace, a method of increasing the outlet resistance of the cathode liquid by reducing the diameter of the outlet pipe on the force source side, and the like.

(C) The technology of Japanese Patent Application No. 1 1—5 1 0 3 3 is based on an anode chamber for disposing a porous anode, a force chamber for distributing a force node, and a force chamber for an anode chamber. A method for producing a polysulfide, which comprises introducing a solution containing sulfide ions into an anode chamber of an electrolytic cell having a diaphragm that partitions a source chamber, and obtaining polysulfide ions by electrolytic oxidation, The porous anode is arranged so as to have a void in at least a part between the porous anode and the diaphragm, and the apparent volume of the porous anode is reduced to an anode chamber. A polysulfide production method characterized by being 60% to 99% of the volume of the polysulfide. According to this method, thiosulfuric acid It is possible to produce a cooking liquor containing a high concentration of polysulfide sulfur and containing a large amount of residual Na ₂ S state while maintaining a high selectivity, with extremely low ion by-products. By using sulfide cooking liquor for cooking, pulp yield can be effectively increased. In addition, pressure loss during the electrolysis operation can be reduced, and clogging of SS (suspended matter) can be suppressed.

In the present technology, the porous anode is arranged so as to have a void in at least a part between the porous anode and the diaphragm, and the apparent volume of the porous anode is reduced. It is configured to be 60% to 99% of the volume of the anode chamber. Here, the volume of the anode chamber is the volume of the space defined by the effective energizing surface of the diaphragm and the apparent surface of the portion of the anodic liquid flow that is the farthest from the diaphragm. The gap formed between the anode and the diaphragm may be formed on the entire effective conducting surface of the diaphragm or may be formed on a part thereof. If there is a possibility that clogging may occur when a solid component having a large particle diameter is mixed in the electrolytic cell, it is preferable that these voids are continuous as a flow path. If the apparent volume exceeds 9.9%, the pressure loss is large in the electrolysis operation, and the suspended solid is easily clogged, which is not preferable. If the apparent volume is less than 6096, the amount of the anode liquid flowing through the porous anode becomes too small, and the current efficiency becomes poor. Within this range, the electrolysis operation can be performed with low pressure loss and good clogging while maintaining good current efficiency. More preferably, this value is set between 70 and 99%. Also, in this technology, it has been found that the gap on the diaphragm side exerts an unexpected effect. In this technology, the anode electrode reaction is considered to occur on almost the entire surface of the porous anode, and the portion near the diaphragm of the anode has a smaller electric resistance of the liquid, so that the current flows more easily. The reaction proceeds. Therefore, at this site, the reaction becomes mass transfer-limited, and by-products such as thiosulfate ion and oxygen are easily formed, and anodic dissolution is more likely to occur. However, when a gap is provided between the porous anode and the diaphragm, the linear velocity of the anodic liquid in the gap increases, and the liquid flow velocity at the diaphragm side portion of the anode increases due to this flow. Therefore, material diffusion in a portion of the anode near the diaphragm is advantageous, and side reactions can be effectively suppressed. In addition, this gap allows the anode fluid to flow smoothly, This has the advantage that deposits can be made less likely on the anode side surface.

 These techniques (A) to (C) are particularly suitable for processing a white liquor or a green liquor in a pulp production process to produce a polysulfide and obtain a NaOH solution. White liquor or green liquor is introduced into the anodic chamber, ie, the anode side of the cell, and the resulting polysulphide is used as it is or after causticization, and added before the chips reach the maximum temperature. In addition, NaOH (containing a small amount of KOH) solution generated in the power source chamber of the electrolytic cell, that is, on the cathode side, is used by adding after the chip reaches the maximum temperature.

 Hereinafter, the same applies to the techniques (B) to (C) which mainly describe the technical content and various aspects of (A) regarding these methods. An alkaline cooking liquor composed mainly of sodium hydroxide and sodium sulfide is supplied to an anode chamber in which an anode is disposed, a cathode chamber in which a cathode is disposed, and an anode chamber of an electrolytic cell having a diaphragm for separating an anode chamber and a cathode chamber. Continuously.

 In this case, the material of the anode is not particularly limited as long as it is alkaline and has oxidation resistance, and a nonmetal or metal is used. As the non-metal, for example, a carbon material can be used, and as the metal, for example, a base metal such as nickel, conoreto, titanium, an alloy thereof, a precious metal such as platinum, gold, rhodium, an alloy, or an oxide thereof Can be. As the structure of the anode, it is preferable to use a porous anode having a physical three-dimensional network structure. Specifically, for example, in the case of a nickel anode material, a porous nickel obtained by applying nickel plating to the skeleton of the foamed polymer material and then firing and removing the internal polymer material can be used.

In the case of the porous anode having a physically three-dimensional network structure, at least the surface of the anode chamber is formed of nickel or a nickel alloy containing nickel of 50% by weight or more in a physically continuous three-dimensional structure. A porous anode having a network structure and having a surface area of the anode per unit volume of the anode chamber of 500 to 2000 m ² / m ³ is provided. Nickel or nickel alloy on at least the surface of the anode makes it practical for polysulfide production It has sufficient durability. The surface of the anode is preferably nickel, but nickel alloys containing more than 50% by weight of nickel may also be used, with nickel content being more than 80% by weight. I like it. Nickel is relatively inexpensive, and its elution potential and oxide formation potential are higher than polysulfate sulfatiosulfate ion formation potential. Therefore, nickel is a suitable electrode material for obtaining polysulfide ions by electrolytic oxidation. is there.

 In addition, since it is porous and has a three-dimensional network structure, it has a large surface area, and when used as an anode, the desired electrolytic reaction occurs on the entire surface of the electrode, suppressing the generation of by-products can do. Further, unlike the aggregate of fibers, the anodic is a physically continuous network structure, so that it exhibits sufficient electrical conductivity as an anodic and can reduce the IR drop in the anodic. Therefore, the cell voltage can be further reduced. In addition, since the anode has good electric conductivity, it is possible to increase the porosity of the anode and reduce the pressure loss.

The surface area of Ano de per unit volume of Ano de chamber, it is necessary that 5 0 0~ 2 0 0 0 0 m 2 / m 3. Here, the volume of the anode chamber is the volume of a portion defined by the effective conducting surface of the diaphragm and the current collector of the anode. If the surface area of the anode is smaller than 500 m ² / m ³ , the current density on the surface of the anode will be large, and only the by-products such as thiosulfate will be easily formed. In addition, nickel is not preferred because it tends to cause anodic dissolution. It is not preferable to increase the surface area of the anode to more than 2000 m ^{2 or 3} m ³ , since there may be a problem in the electrolytic operation such as an increase in the pressure loss of the liquid. More preferably, the surface area of the anode per unit volume of the anode chamber is in the range of 1000 to 1000 m ² Zm ³ .

The surface area of the anode is preferably 2 to 100 m ² / m ² per unit area of the diaphragm separating the anode chamber and the force source chamber. More preferably, the surface area of the anode is 5 to 50 m ² / m ² per unit area of the diaphragm. The average pore size of the anodic mesh is preferably between 0.1 and 5 mm. If the average pore size of the mesh is larger than 5 mm, the surface area of the anode cannot be increased, the current density on the surface of the anode increases, and by-products such as thiosulfate ions are generated. Not only is it not easy to crumble, but nickel is not preferred because it tends to cause anodic dissolution. The average pore size of the mesh is 0. If the diameter is smaller than 1 mm, it is not preferable because a problem in electrolytic operation such as a large pressure loss of the liquid may occur. More preferably, the mean pore size of the anode mesh is 0.2 to 2 mm.

 In the three-dimensional mesh structure, it is preferable that the diameter of the wire constituting the mesh is 0.01 to 2 mm. Wires with a diameter of less than 0.01 mm are not preferred because they are extremely difficult to manufacture, costly, and difficult to handle. If the diameter of the filament exceeds 2 mm, a large surface area of the anode cannot be obtained, the current density on the surface of the anode increases, and by-products such as thiosulfate are easily formed. I don't like it. It is particularly preferable that the diameter of the wire constituting the mesh is 0.02 to 1 mm.

The anode may be disposed at a short distance from the anode chamber so as to be in contact with the diaphragm, or may be disposed so as to have some gap between the anode and the diaphragm. Since the liquid to be treated needs to circulate through the anode, it is preferable that the anode has a sufficient space. In each of these cases, the porosity of the anode is preferably 90 to 99%. If the porosity is less than 90%, the pressure loss in the anode increases, which is not preferable. If the porosity exceeds 9.9%, it is not preferable because it is difficult to increase the anode surface area. It is particularly preferable that the porosity is 90 to 98%. (C) In the technology disclosed in Japanese Patent Application No. 11-501303, when a porous anode is used as the anode, the distance between the porous anode and the diaphragm is reduced by the addition of the anode. The amount of by-products of thiosulfate is extremely low, contains high concentrations of polysulfide, and has a residual Na 2 S state between the volume of the porous chamber and the apparent volume of the porous anode. They found that there were important requirements for producing a large amount of cooking liquor while maintaining a high selectivity, and set those requirements. In this technique, the obtained polysulfide cooking liquor can be used for cooking to effectively increase the pulp yield. 0.. 5 to 2 0 k to operate in AZ m ² is not to prefer. Current density at the diaphragm surface is 0. 5 k If less than AZ m ² is not properly preferred because it is necessary a large electrolyzer unnecessarily. When the current density at the diaphragm surface exceeds 20 kA / m ² , not only increases in by-products such as thiosulfuric acid, sulfuric acid, and oxygen, but also nickel may cause anodic dissolution. Not preferred. If the current density at the diaphragm surface is 2~ 1 5 k AZ m ² Is even more preferred. Since an anode with a large surface area is used for the area of the diaphragm, it can be operated in a range where the current density on the anode surface is small.

Since the anode has a large surface area, the current density on the anode surface can be reduced. Assuming that the current density on the surface of each part of the anode is uniform, when the current density on the surface of the anode is calculated from the surface area of the anode, the value is 5 to 300 A / m ² is preferred. Good Ri preferred correct range is 1 0~ 1 5 0 0 A // m 2. If the current density on the anode surface is less than 5 AZm ² , unnecessarily large electrolytic equipment is required, which is not preferable. If the current density at the anodic surface is more than ^{3 0 0 0 A / m 2} , not only increases the Chio sulfate, sulfate, by-products such as oxygen, nickel is likely to cause § Roh one de dissolution Not so desirable. Unlike an aggregate of fibers, this anode is a physically continuous network structure and has sufficient electrical conductivity, so that the IR drop of the anode can be kept small while maintaining a small IR drop. The porosity can be increased. Therefore, the pressure loss of the anode can be reduced.

 It is preferable to maintain the liquid flow in the anode chamber in a laminar flow region with a small flow velocity in order to reduce the pressure loss. However, in the laminar flow, the anolyte solution in the anodic chamber is not agitated, and in some cases, deposits tend to accumulate on the diaphragm facing the anodic chamber, and the cell voltage tends to increase with time. In this case, the pressure loss of the anode can be kept small even if the anode liquid flow rate is set to be large, so that the anode liquid near the surface of the diaphragm can be agitated and the deposits can be hardly accumulated. There is. The average superficial velocity in the anode chamber is preferably 1 to 30 cmZ seconds. The flow velocity of the power source liquid is not limited, but is determined by the magnitude of the buoyancy of the generated gas. A more preferable range of the average superficial velocity of the anode chamber is 1 to 15 cmZ seconds, and a particularly preferable range is 2 to 10 cmZ seconds.

As a force source material, a material having an anti-strength property is preferable. For example, nickel, Raney-nickel, steel, stainless steel, or the like can be used. The force sword is one of a flat plate or mesh shape, or a plurality of them are used in a multilayer structure. A three-dimensional electrode combining linear electrodes can also be used. The electrolytic cell is a two-chamber electrolytic cell consisting of one anode chamber and one cathode chamber, or three or more electrolytic cells. An electrolytic cell combining rooms is used. Multiple cells can be arranged in a monopolar or bipolar configuration.

 It is preferable to use a cation exchange membrane as a membrane separating the anode chamber and the cathode chamber. The cation exchange membrane directs cations from the anode compartment to the force sword compartment, preventing the transfer of sulfide and polysulfide ions. As the cation exchange membrane, a polymer membrane in which a cation exchange group such as a sulfone group or a sulfonic acid group is introduced into a hydrocarbon-based or fluororesin-based polymer is preferable. If there is no problem in terms of alkali resistance and the like, a bipolar membrane, an anion exchange membrane, or the like can be used.

The electrolysis conditions such as temperature and current density depend on multi-fluid ion (S x ² —) such as S ₂ ² —, S 3 ² ”, S 4 ² —, and S ₅ ² as oxidation products of sulfide ions at the anode. That is, it is preferable to adjust and maintain such that polysulfide ions are generated and thiosulfate ions are not produced as by-products, so that sodium sulfide is not substantially produced as by-products by electrolytic oxidation of sodium sulfide. Highly efficient, it can produce alkaline cooking liquor with a polysulfide sulfur concentration of 8 to 20 g ZL as sulfur.Of course, by selecting electrolytic conditions such as temperature, current density, etc., polysulfide sulfur below 8 g ZL Concentrated cooking liquors can also be produced.

In the present invention, the cooking liquor is divided and added to a plurality of points in the cooking system, that is, the digester, and the first cooking liquor is supplied to the top of the digester. In the present invention, as the first cooking liquor, 45 to 100% by weight based on the total amount introduced into the cooking system, and preferably 50 to 100% by weight. % of steam solutions active sulfur, 4 5-7 9 wt% of effective alkali, effective alkali favored properly 5 0-6 0 weight _^0/0 is supplied to the whole amount to be introduced into the cooking system This is very important.

If the sulfur content of the cooking liquor of the first cooking liquor is less than 45% by weight, the first half of the cooking becomes sodium sulfide deficient, and selective delignification is not performed. The resulting pulp will have an increased strength value and a reduced yield. Even when the cooking sulfur-content of the first cooking liquor and 1 0 0 wt _^0/0 good strength wrapper titer and yield of pulp obtainable. About the effective power of the first cooking liquor If the amount is less than 45% by weight, the first half of the digestion will be insufficient in alkali and the yield will be greatly impaired. In addition, when the effective alkali of the first cooking liquor exceeds 79%, the effective alkali contained in the following second cooking liquor added during the course of cooking decreases, so that the latter half of the cooking is short of effective alkali. And the resulting pulp will have an increased monovalent value and a reduced yield.

 As the second cooking liquor, sodium hydroxide or sodium sulfide or the like is the main component or sodium hydroxide at the bottom of the upper cooking zone after the cooking temperature reaches the maximum. And the like are supplied. The sulphidity of the cooking liquor is 0 to 40%. Further, as the third cooking liquor, the same type of cooking liquor as the second cooking liquor is supplied from the bottom of the zone of the cooking washing zone in the latter half of the cooking. As the second and third cooking liquors, specifically, is it desirable to use a white liquor containing sodium hydroxide and sodium sulfide as main components? More preferably, when polysulfide is obtained by electrolysis, an alkaline cooking liquor containing sodium hydroxide as a main component produced at the cathode is used.

 As described above, in the present invention, first, an alkaline cooking liquid mainly composed of polysulfide and sodium hydroxide is added together with chips at the top of the digester, and sodium hydroxide is added during the digestion in the digester. An alkaline cooking liquor consisting mainly of sodium and sodium sulfide or an alkaline cooking liquor consisting mainly of sodium hydroxide is added. In this way, a more effective polysulphide digestion can be carried out in a single vessel digester by adding different types of alkaline cooking liquor to the digester from multiple locations. be able to.

Further, in the present invention, 2 0-6 0 volume _^0/0 of the total cooking black liquor fed directly recovery process from the digester is extracted with be sampled, single Na overhead zone bottom out discharge outside the digestion system May be done. If the cooking liquor discharged to the outside of the cooking system at this point is less than 20% by volume of the total cooking liquor, a large amount of dissolved organic matter mainly composed of lignin remains in the digester, and The reduction in kappa monovalent is small, and there is no improvement in the relationship between kappa monovalent and pulp yield. On the other hand, at this point If the amount of cooked black liquor exceeds 60% of the total cooked black liquor, there will be insufficient cooking power after the upper cooking zone, resulting in shortage of cooking and an increase in kappa monovalent.

 Next, regarding the addition of the quinone compound in the polysulphide digestion, an effective method of adding the quinone compound by the MCC method or the L 0 -S 0 1 ids (registered trademark) method was not clear. According to the above, it is important to enhance the effect of the quinone compound as a cooking aid by conducting the cooking as described above and adding the quinone compound to the top of the digester or the bottom of the upper cooking zone. Power, one 7 :.

 Therefore, in the present invention, the quinone compound is contained in an amount of 0.01 to 1.5% by weight, preferably 0.01 to 0.15% by weight, more preferably 0.02% by weight, based on the absolutely dry chips. It is added to the first cooking liquor supplied to the top of the digester or to the second alkaline cooking liquor supplied to the bottom of the upper cooking zone so as to be ~ 0.06% by weight. If the addition of the quinone compound is less than 0.01% by weight, the addition amount is too small, so that the pulp monovalent value of the pulp after digestion is not reduced, and the relationship between the pulp value and the pulp yield is not improved. Further, even if the quinone compound is added in excess of 1.5% by weight, no further reduction in the pulp power after cooking and no improvement in the relationship between the pulp monovalue and the pulp yield are observed.

In order to obtain the effect of the quinone compound, it is preferable that the quinone compound coexist as long as possible with the chips in the digester, and that the quinone compound be added where the delignification of the digestion proceeds. Therefore, in the digestion method using the one-vessel digester of the present invention, the quinone compound is preferably added to the bottom of the upper digestion zone. Further, in the present invention, an alkaline cooking liquor containing polysulfide is supplied together with the chips from the top of the digester. In order to obtain the polysulfide decomposition moderating effect of the quinone compound disclosed in Japanese Patent Application Laid-Open No. 57-29690, the quinone compound and the polysulfide must be coexistent for as long as possible. It is preferable to add a quinone compound to the top of the digester. The quinone compound used is a quinone compound, a hydroquinone compound or a precursor thereof as a so-called known cooking aid, and at least one compound selected from these can be used. . These compounds include, for example, anthraquinone, dihydroanthraquinone (for example, 1,4-dihydroantraquinone), and tetrahydroanthraquinone (for example, 1,4,4a, 9a-te) Trahidroantraquinone, 1,2,3,4-tetrahydroanthraquinone, methylanthraquinone (eg, 1-methylanthraquinone, 2-methylanthraquinone), methyldihydroantraquinone For example, 2-methyl-1,4-dihydroanthraquinone), methyltetrahydroantraquinone (for example, 1-methyl-1,4,4a, 9a—tetrahydrantraquino) Quinone compounds such as 1,2-methyl-1,4,4a, 9a-tetrahydrohydroanthraquinone, and anthrahydroquinone. 9,10-dihydroxianthracene, methylanthrahydroquinone (for example, 2—methylanhydroquinone), dihydroantrahydroquinone (for example, 1,4—dihydraquinone) , 10 — dihydroxythracene) or an alkali metal salt thereof (eg, dinatrium salt of anthrahydroquinone, 1, 4 — dihydro_9, 10 — dinat of dihydroxianthracene) And a precursor such as anthrone, anthranol, methylanthrone, and methylanthranol. These precursors may be quinone compounds under digestion conditions, or coniferous or hardwood chips may be used as the lignocellulosic material used in the present invention. For example, conifers include spruce, Douglas fir, pine, and cedar, and hardwood include eucalyptus, beech, and oak.

Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to the following description. FIG. 1 shows a 1-vessel type continuous digester for implementing the L 0 -S 0 1 ids (registered trademark) method preferably used in the present invention. It is a figure showing an example of a mode. The digester 2 is divided into four zones from top to bottom: top zone A, upper digestion zone B, lower digestion zone C, and digester zone D. Cooking wash zone D is not required, but is preferred. Strainers are provided at the bottom of each zone, the upper extraction strainer 4 at the bottom of the first top zone A, the strainer 5 at the bottom of the second upper cooking zone B, and the third lower cooking, respectively. The lower extraction strainer 6 at the bottom of zone C, and the fourth strainer at the bottom of digestion zone D.

 Chip 1 is fed to the top of digester 2 and enters top zone A. On the other hand, the first alkaline cooking liquor composed mainly of polysulfide and sodium hydroxide is supplied to the top of the digester 2 through an alkaline cooking liquor supply pipe 3 containing polysulfide. Chips supplied and filled at the top of digester 2 descend together with the cooking liquor, during which time the first cooking liquor works effectively to cause initial delignification and lignin from the chips to the cooking liquor. Is eluted. Then, a predetermined amount of the digested black liquor containing lignin from the chips is extracted from the upper extraction strainer 4 and sent to the recovery step through the black liquor discharge conduit 10. Chips descending from overhead zone A enter upper digestion zone B. In this zone, the chips reach the maximum cooking temperature and delignification proceeds further. Cooking black liquor is extracted from the strainer 5 provided at the bottom of the upper cooking zone B by the extraction liquid conduit 17. This extracted cooking black liquor is provided in an extraction liquid conduit 17 with a second cooking liquid, that is, sodium hydroxide and sodium sulfide flowing through an upper cooking liquid supply pipe 8. Alternatively, sodium hydroxide is combined with the alkaline cooking liquid of the main component and the quinone compound-containing liquid supplied from the quinone compound supply conduit 16 and is heated by the heater 14 provided in the flow path. Heated. This circulating liquid (upper cooking circulating liquid) is supplied via the upper cooking circulating liquid conduit 19 in the vicinity of the strainer 5 at the bottom of the upper cooking zone B.

In the upper digestion zone B, chips are stored at the bottom of the upper extraction strainer 4 The force ^s descending toward the upper part of the strainer 5, during this time, the circulating cooking liquor supplied from the circulating fluid conduit 19 near the strainer 5 rises toward the upper extraction strainer 4, and The delignification reaction proceeds by countercurrent cooking by the action of liquid. The circulated cooking liquor rising toward the upper extraction strainer 4 becomes black liquor, is extracted from the upper extraction strainer 4, and is sent to the recovery step through the black liquor discharge conduit 10. The chips delignified in the upper digestion zone B enter the lower digestion zone C below the strainer 5, and are further delignified by co-current digestion with the second digestion liquor. The digested black liquor obtained in this zone is extracted from the lower extraction strainer 6 at the bottom of the lower digestion zone C and sent to the recovery step through the black liquor discharge conduit 11.

 Chips descending from lower cooking zone C enter cooking washing zone D. In this zone, the chips undergo countercurrent cooking and delignification proceeds further. The cooking black liquor extracted from the strainer 7 near the bottom of the digester provided at the lower part of the digestion washing zone D is connected to the sodium hydroxide and the sodium hydroxide flowing through the lower alkaline cooking liquor supply pipe 9 in the extract conduit 18. It is combined with an alkaline cooking liquor composed mainly of sodium sulfide or sodium hydroxide, and heated by a heater 15 provided in the flow path. This circulating fluid is supplied near the strainer 7 through the lower circulating fluid conduit 20.

 In the digestion washing zone D, the chips descend from the lower extraction strainer 6 toward the strainer 7. During this time, the circulated cooking liquor supplied from the lower circulating liquid conduit 20 near the strainer 7 rises toward the lower extraction strainer 6, and the cooked black liquor is extracted from the lower extraction strainer 6, and the black liquor is extracted from the lower extraction strainer 6. It is sent to the recovery process through the liquid discharge conduit 11. In this zone, the cooking reaction is completed, and pulp is obtained via the cooking pulp discharge pipe 12.

In digester 2, the initial temperature in the top zone A is around 120 ° C, and it reaches the maximum cooking temperature in the range of 140 to 170 at the bottom of the top zone A. In the upper digestion zone B and the lower digestion zone C, it is kept at the maximum temperature within the range of 140 to 170 ° C. The temperature decreases from the highest cooking temperature in the range of 140 to 170 ° C to around 140 ° C toward the bottom of zone D.

 Example.

 Hereinafter, the present invention will be described in more detail with reference to Examples, but it is needless to say that the present invention is not limited by these Examples. Examples 1 to 8, 11 to 18 and Comparative Examples 1 to 4 and 9 to 11 show mixed chips of softwood, and Examples 9 and 10 and Comparative Examples 5 to 8 show mixed chips of hardwood. Examples 1 to 8, 11 to 18 and Examples 9 and 10 were cooked by the method of the present invention.

Cooking was indexed by H-factor (HF). H-factor is a measure of the total amount of heat applied to the reaction system during the digestion process, and is represented by the following equation in the present invention. Where HF is the H-factor, T is the absolute temperature at a point in time, and dt is a function of time that changes over time due to the temperature profile in the digester. H-factor-1 is calculated by integrating the term on the right side of the integral symbol over time from the time when the chips and the total digestive liquid power are mixed ⁵ to the end of the digestion.

HF = SI n— ¹ (43.20-16113 / T) dt

《Test method》

The pulp yield of the obtained unbleached pulp was obtained by measuring the yield of selected pulp from which Kashiwa was removed. Kappa monovalent of unbleached pulp was performed in accordance with TAP PI test method T236οs-76. Quantification of sodium sulfide and polysulfide concentration in terms of sulfur in the alkaline cooking liquor was carried out in accordance with TA II III Test Method T 624 hm-85. The pulp yield was calculated based on the carbohydrate yield obtained according to TAPPI test method T 24 9 hm — 85 and the pulp alcohol and benzene extract obtained according to TAPPI test method T 204 0 s — 76 and the TAPPI test method T 222 os Add the acid-insoluble lignin of the pulp I was happy.

<< Example 1 >>

Chips mixed with absolute dry weight% of radiatapine 40, Douglas fir 30 and larch 30 were used for digestion using the continuous digester shown in FIG. Total effective alkali addition rate is 1 4.5, 1 6.5, 1 8.5 wt%; was performed in three (pairs bone-dry chip N a ₂ 0 equivalent). As the first cooking liquor to be added at the top of the kettle, polysulfuric acid obtained by electrolyzing an alkaline solution containing sodium hydroxide and sodium sulfide as the main components in the following electrolytic cell was used. Dosarufu § concentration 4 g / L (terms of sulfur), 0 hydroxide Na Application Benefits © beam concentration _{7 g / L (N a 2} 0 equivalent) and sulfide Na Application Benefits um concentration 2 2 g / L (N a 2 0 in terms of ) Is composed of 50% by weight of sulfur (53% by weight) and 50% by weight of sulfuric acid-based cooking liquor containing polysulphide as the main component. It was added so as to be effective alkali. At that time, the liquid ratio was about 3.5 L / kg with respect to the absolutely dry chips, together with the moisture brought in by the chips.

The electrolytic cell was configured as follows. Nickel porous material as anode (anodic surface area per anode chamber volume: 560 OmVm ³ , average pore size of mesh: 0.51 mm, surface area to diaphragm area: 28 m ² Zm ³ ), iron exponsion metal as power source, diaphragm as diaphragm A two-chamber electrolytic cell composed of a fluorinated resin-based cation exchange membrane was assembled.

 From the upper extraction strainer, 45% by volume of the total digested black liquor was extracted. In the upper cooking zone, a second cooking liquor with a sulphidity of 30% was added to make 31.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digestion washing zone, a liquid having the same composition as the second cooking liquor of 30% sulphide was added so that the effective amount of liquid was 18.4% by weight based on the total amount introduced into the cooking system. .

In the top zone, heat from 120 ° C to 140 ° C in 30 minutes from the top to the bottom of the top zone, and in the upper digestion zone, hold at 150 ° C for 50 minutes, In the digestion zone, it is kept at 156 ° C for 160 minutes, and in the digestion washing zone, From the top to the bottom of the digestion washing zone, the temperature was reduced from 156 to 140 ° C in 170 minutes, and the H-factor was reduced to 1400. As the quinone compound, 1,4,4a, 9a-tetrahydroanthraquinone is mixed with the second cooking liquor added in the upper cooking zone at 0.05% by weight to the absolutely dry chip. Was. Table 1 shows the cooking results. According to this example, as compared with Comparative Examples 1 to 4, kappa monovalent at the same effective alkali addition rate was reduced, and pulp yield at the same kappa monovalent was increased.

<< Example 2>

Chips used for cooking, total effective alkali addition rate, liquid ratio, method and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, temperature and time of digester, H—factor 1 The addition of the quinone compound was performed in the same manner as in Example 1. First cooking liquor added at the top of the kettle, was set to sulfur and 7 0% by weight of the active Al force Li 7 2 weight _^0/0 against the total amount to be introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor with 30% sulphide was added to make 21.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digestion washing zone, a liquid having the same composition as the second cooking liquid having a sulfuration degree of 30% was added so as to become 8.4% by weight of the effective alkali with respect to the total amount introduced into the cooking system. Table 1 shows the cooking results. According to the present example, the kappa monovalent value at the same effective alkali addition rate was reduced and the pulp yield at the same power value was increased as compared with Comparative Examples 1 to 4.

<< Example 3>

Chips used for cooking, total available alkali addition rate, liquid ratio, preparation and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, temperature, time, H-factor and The quinone compound was added in the same manner as in Example 1. The first cooking liquor added at the top of the kettle should have a sulfur content of 100% by weight and an effective capacity of 50% by weight, based on the total amount introduced into the cooking system. did. The upper cooking zone, a second cooking liquor sodium hydroxide is the main component, 3 1. Was so that added a 6 weight _^0/0 effective Al force Li content of the total amount to be introduced into the cooking system . At the bottom of the digestion zone, a liquor of the same composition as the second liquor was added to give an effective alkali of 18.4% by weight, based on the total amount introduced into the digestion system. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the cooking washing zone used an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. Table 1 shows the cooking results. According to this example, as compared with Comparative Examples 1 to 4, the copper value at the same effective alkali addition rate was reduced, and the pulp yield at the same power value was increased.

<< Example 4>

 Chips used for cooking, total effective alkali addition rate, liquid ratio, preparation and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, digester temperature, time, H-factor The addition of the quinone compound was performed in the same manner as in Example 1. The first cooking liquor added at the top of the kettle was such that it had a sulfur content of 100% by weight and an effective capacity of 70% by weight, based on the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor containing sodium hydroxide as a main component was added so as to provide an effective amount of 21.6% by weight based on the total amount introduced into the cooking system. At the bottom of the digestion zone, a liquid having the same composition as the second cooking liquor was added so as to be 8.4% by weight of the effective alkali with respect to the total amount introduced into the cooking system. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the cooking washing zone used an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. Table 1 shows the cooking results. According to this example, the katsuno at the same effective alkali addition rate as compared with Comparative Examples 1 to 4. —The pulp yield was reduced and the pulp yield at the same power was increased.

<< Example 5>

Chips used for cooking, total effective alkali addition rate, liquid ratio, amount of black liquor extracted from upper extraction strainer, digester temperature, time, H-factor and The quinone compound was added in the same manner as in Example 1. As the first cooking liquor to be added at the top of the kettle, an alkaline solution mainly containing sodium hydroxide and sodium sulfide was introduced into the electrolytic cell, obtained electrochemically oxidizing sulfide Na birds © beam sexual solution Porisarufai Dosarufa concentration 1 0 g / L (terms of sulfur), hydroxide Na Application Benefits um concentration _{7 0 g ZL (N a 2} 0 equivalent) and sulphide Na Application Benefits um concentration _{1 1 g ZL (N a 2} 0 equivalent) Al force Li of cooking liquor of the main component, sulfur and 5 of 5 5% by weight based on the total weight to be introduced into the cooking system It was added so as to become 0% by weight of effective alkali. In the upper cooking zone, a second cooking liquor of 30% sulphide was added to give an effective alkali of 31.6% by weight, based on the total amount introduced into the cooking system. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquid having a sulfuration degree of 30% was added so as to be 18.4% by weight of an effective alkali with respect to the whole amount introduced into the cooking system. Table 2 shows the cooking results. According to the present example, as compared with Comparative Examples 1 to 4, the monovalent monovalent force at the same effective alkali addition rate was decreased, and the pulp yield at the same monovalent monovalent kappa was increased.

<< Example 6>

Examples of chips used for cooking, total effective alkali addition rate, liquid ratio, amount of black liquor extracted from upper extraction strainer, temperature and time of digester, addition of H-factor and quinone compound In the same manner as in Example 1, the production method and composition of the first cooking liquor were performed in the same manner as in Example 5. First cooking liquor added at the top of the kettle was so relative to the total amount to be introduced into the cooking system becomes 7 4 wt% of sulfur and 7 0 wt _^0/0 of the effective § alkali. In the upper cooking zone, a second cooking liquor with 30% sulphide was added to give an effective alkali content of 21.6% by weight, based on the total amount introduced into the cooking system. At the bottom of the digestion wash zone, a liquid of the same composition as the second digestion liquor of 30% sulphide was added so as to give an effective alkali of 8.4% by weight based on the total amount introduced into the digestion system. Table 2 shows the cooking results. According to this example, as compared with Comparative Examples 1 to 4, the katsuno and monovalent at the same effective alkali addition rate were reduced, and the pulp yield at the same power monovalent was increased. <Example 7>

 Chips used for cooking, total effective alkali addition rate, liquid ratio, amount of black liquor extracted from upper extraction strainer, temperature and time of digester, H-factor-1 and addition of quinone compound The procedure and the composition of the first cooking liquor were performed in the same manner as in Example 1 and in Example 5. The first cooking liquor added at the top of the kettle was made up to 100% by weight sulfur and 50% by weight available alkali based on the total amount introduced into the cooking system. In the upper cooking zone, sodium hydroxide added the second cooking liquor of the main component to 31.6% by weight of available alkali, based on the total amount introduced into the cooking system. At the bottom of the digestion wash zone, a liquid having the same composition as the second digestion liquor was added so as to have an effective alkali content of 18.4% by weight based on the total amount introduced into the digestion system. Table 2 shows the cooking results. According to the present example, the kappa value at the same effective alkali addition rate was decreased and the pulp yield at the same effective monovalent value was increased as compared with Comparative Examples 1 to 4.

<< Example 8>

The chips used for cooking, the total effective alkali addition rate, the liquid ratio, the amount of black liquor extracted from the upper extraction strainer, the temperature and time of the digester, the addition of H-factor and quinone compounds The procedure and the composition of the first cooking liquor were carried out in the same manner as in Example 1 and in the same manner as in Example 5. The first cooking liquor added at the top of the kettle was made up to 100% by weight sulfur and 70% by weight available alkali relative to the total amount introduced into the cooking system. In the upper cooking zone, sodium hydroxide was added to the second cooking liquor, the main component, to make 21.6% by weight of the effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquor was added so as to have an effective alkali content of 8.4% by weight based on the total amount introduced into the cooking system. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the cooking washing zone used an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. Table 2 shows the cooking results. According to this example, the pulp value at the same effective alkali addition rate was reduced, and the pulp yield at the same power value was lower than in Comparative Examples 1 to 4. Increased rate.

 << Example 9>

Hardwood chips of acacia 30, oak 30, and eucalyptus 40 mixed at an absolute dry weight of 6 were used for cooking using the continuous digester shown in FIG. Total effective alkali addition rate is 1 1.9, 1 2.8, 1 3.6 wt _^0/0; was performed in three (pairs bone-dry chip N a ₂ 0 equivalent). The method and composition of the first cooking liquor used for cooking, and the amount of black liquor extracted from the upper extraction strainer were the same as in Example 1. The first cooking liquor added at the top of the kettle was such that it contained 53% by weight of sulfur and 50% by weight of the total amount introduced into the cooking system. At that time, the liquid ratio was about 2.5 LZ kg with respect to the absolutely dry chips, including the water brought in by the chips. At the bottom of the cooking wash zone, a second cooking liquor with a sulphidity of 309 was added so as to give an effective alkali of 31.6% by weight based on the total amount introduced into the cooking system. In the lower cooking zone, a liquid having the same composition as that of the second cooking liquor having a sulphidity of 30% was added so as to obtain an effective alkali of 18.4% by weight based on the total amount introduced into the cooking system. As the quinone compound, 1,4,4a, 9a-tetrahydroanthraquinone is added to the second cooking liquor in which 0.03% by weight is added to the absolutely dry chips in the upper cooking zone. Mixed. In the top zone, heat from 120 ° C to 140 ° C in 20 minutes from the top to the bottom of the top zone, and in the upper digestion zone, keep it at 15 ° C for 30 minutes. In the lower cooking zone, the temperature is maintained at 152 ° C for 120 minutes, and in the cooking and washing zone, the temperature is from 150 to 140 ° C from 140 to 140 ° C from the top to the bottom of the cooking and washing zone. The digestion was carried out to a H-factor of 1830. Table 4 shows the cooking results. According to this example, as compared with Comparative Examples 5 to 8, kappa monovalent at the same effective alkali addition rate was reduced, and pulp yield at the same kappa monovalent was increased.

<< Example 10 >> The chips used for cooking, total effective alkali addition rate, liquid ratio, digester temperature, time, addition of H-factor and quinone compound were the same as in Example 9, and the cooking black liquor from the upper extraction strainer was used. The amount of extraction was the same as in Example 1, and the production method and composition of the first cooking liquor were the same as in Example 5. The first cooking liquor, added at the top of the kettle, was added to give 100% by weight sulfur and 50% by weight available alkali to the total amount introduced into the cooking system. At the bottom of the digestion zone, a second cooking liquor containing sodium hydroxide as a main component was added so as to provide an effective amount of 31.6% by weight based on the total amount introduced into the cooking system. . In the lower cooking zone, a liquor of the same composition as the second liquor was added to give an effective alkali of 18.4% by weight, based on the total amount introduced into the cooking system. The second cooking liquor to be added at the bottom of the upper digestion //-and the cooking liquor to be added at the bottom of the digestion washing zone use an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. did. Table 4 shows the cooking results. According to this example, the kappa monovalent at the same effective alkali addition rate was reduced and the pulp yield at the same power monovalent was increased as compared with Comparative Examples 5 to 8.

<< Example 11 >>

Chips used for cooking, total available alkali addition rate, liquid ratio, preparation and composition of first cooking liquor, amount of cooking black liquor extracted from upper extraction strainer, digester temperature, time and H-fa The procedure of Example 1 was repeated, and the addition of the quinone compound was performed in the same manner as in Example 11. 1 is a quinone compound, 4, 4 a, 9 a- Te Torahi Doroan Torakino 0 down against bone-dry chip. 0 5 wt _^0/0 second cooking added above section cooking zone one down The solution was mixed. The first cooking liquor added at the top of the kettle was made up to 53% by weight of sulfur and 50% by weight of the effective amount of the total amount introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor with a sulphidity of 3096 was added to give an effective altitude of 31.6% by weight, based on the total amount introduced into the cooking system. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquor having a sulfuration degree of 30% is converted into an effective alkali of 18.4% by weight with respect to the total amount introduced into the cooking system. Was added. Digestion The results are shown in Table 6. According to this example, as compared with Comparative Examples 2 and 9 to 11, the value of monopulp at the same effective addition rate was reduced, and the pulp yield at the same value of kappa was increased. .

 << Example 1 2>

 Chips used for cooking, total effective alkali addition rate, liquid ratio, preparation and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, temperature, time and H-fat Was performed in the same manner as in Example 1, and the addition of the quinone compound was performed in the same manner as in Example 11. The first cooking liquor added at the top of the kettle was such that it contained 72% by weight of sulfur and 70% by weight of effective alkali relative to the total amount introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor of 30% sulphide was added to give 21.6% by weight of effective alkali based on the total amount introduced into the cooking system. At the bottom of the digestion zone, a liquid having the same composition as the second cooking liquor with a sulfuration degree of 30% was added so as to be 8.4% by weight of the total amount introduced into the cooking system. . Table 6 shows the cooking results. According to the present example, the kappa monovalent at the same effective alkali addition rate was reduced and the pulp yield at the same kappa monovalent was increased as compared with Comparative Examples 2 and 9 to 11. .

 << Example 1 3>

Chips used for cooking, total effective addition rate, liquid ratio, method and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, temperature, time and H-factor of digester One was as in Example 1, and the addition of the quinone compound was as in Example 11. The first cooking liquor added at the top of the kettle was such that it had a sulfur content of 100% by weight and an effective alkali of 50% by weight, based on the total amount introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor composed mainly of sodium hydroxide was added so as to have an effective alkali content of 31.6% by weight based on the total amount introduced into the cooking system. did. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquor was added so as to give an effective amount of 18.4% by weight based on the total amount introduced into the cooking system. Added at the bottom of the upper cooking zone For the second cooking liquor to be added and the cooking liquor to be added at the bottom of the digestion washing zone, an alkaline solution mainly composed of sodium hydroxide generated in the cathode by electrolysis was used. Table 6 shows the cooking results. According to this example, as compared with Comparative Examples 2 and 9 to 11, the power pper value at the same effective power addition rate was reduced, and the pulp yield at the same power porosity was increased.

<< Example 14>

 The chips used for cooking, the total effective alkali addition rate, the liquid ratio, the preparation and composition of the first cooking liquor, the amount of black liquor extracted from the upper extraction strainer, the temperature, time and H-factor of the digester are as follows: In the same manner as in Example 1, the addition of the quinone compound was performed in the same manner as in Example 11. The first cooking liquor added at the top of the kettle was such that 100% by weight of sulfur and 70% by weight of effective alkali were based on the total amount introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor consisting mainly of sodium hydroxide was added to make up an effective amount of 21.6% by weight of the total amount introduced into the cooking system. did. At the bottom of the digestion zone, a liquid having the same composition as the second cooking liquor was added so as to be 8.4% by weight of the effective alkali with respect to the total amount introduced into the cooking system. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the cooking washing zone are mainly composed of sodium hydroxide generated on the cathode by electrolysis. A solution was used. Table 6 shows the cooking results. According to this example, as compared with Comparative Examples 2 and 9 to 11, the monovalent monovalent force at the same effective alkali addition rate was reduced, and the pulp yield at the same monovalent monovalent kappa was increased.

<< Example 15>

The chips used for cooking, total effective alkali addition rate, liquid ratio, amount of black liquor extracted from the upper extraction strainer, digester temperature, time and H-factor were the same as in Example 1. Similarly, the production method and composition of the first cooking liquor were the same as in Example 5, and the addition of the quinone compound was performed in the same manner as in Example 11. The first cooking liquor added at the top of the kettle was 55% by weight sulfur based on the total amount introduced into the cooking system. It was added so as to have a yellow content and an effective concentration of 50% by weight. At the bottom of the upper cooking zone, a second cooking liquor of 30% sulphide was added so as to be 31.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digestion washing zone, a liquid of the same composition as the second cooking liquor with 30% sulphide is added to make 18.4% by weight of effective alkali with respect to the total amount introduced into the cooking system. Was. Table 7 shows the cooking results. According to this example, as compared with Comparative Examples 2 and 9 to 11, kappa monovalent at the same effective alkali addition rate was reduced and pulp yield at the same kappa monovalent was increased.

<< Example 16>

 The chips used for cooking, the total effective alkali addition rate, the liquid ratio, the amount of black liquor extracted from the upper extraction strainer, the temperature and time of the digester, and the H-factor were the same as in Example 1. The production method and composition of the first cooking liquor were the same as in Example 5, and the addition of the quinone compound was performed as in Example 11. The first cooking liquor added at the top of the kettle was such that it contained 74% by weight of sulfur and 70% by weight of the total amount introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor of 30% sulphide was added to give an effective alkali content of 21.6% by weight, based on the total amount introduced into the cooking system. At the bottom of the cooking zone, a liquid having the same composition as the second cooking liquid having a sulfuration degree of 30% was added so as to be 8.4% by weight of the effective alkali with respect to the total amount introduced into the cooking system. . Table 7 shows the cooking results. According to this example, compared to Comparative Examples 2 and 9 to 11, kappa monovalent at the same effective alkali addition rate was reduced, and pulp yield at the same kappa monovalent was increased.

<< Example 1 7>

The chips used for cooking, the total effective alkali addition rate, the liquid ratio, the amount of black liquor extracted from the upper extraction strainer, the temperature and time of the digester, and the H-factor were the same as in Example 1. The production method and composition of the first cooking liquor were the same as in Example 5, and the addition of the quinone compound was performed as in Example 11. The first cooking liquor added at the top of the kettle contains 100% by weight of sulfur, based on the total amount introduced into the cooking system. And 50% by weight. At the bottom of the upper cooking zone, a second cooking liquor composed mainly of sodium hydroxide was added so as to give an effective amount of 31.6% by weight of the total amount introduced into the cooking system. At the bottom of the digestion zone, a liquid having the same composition as the second cooking liquor was added so as to have an effective alkali content of 18.4% by weight based on the total amount introduced into the cooking system. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the cooking washing zone used an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. . Table 7 shows the cooking results. According to this example, as compared with Comparative Examples 2 and 9 to 11, kappa monovalent at the same effective alkali addition rate was reduced, and pulp yield at the same kappa monovalent was increased.

<< Example 18>

 The chips used for cooking, the total effective addition rate, the liquid ratio, the amount of black liquor extracted from the upper extraction strainer, the temperature, time and H-factor of the digester were the same as in Example 1. The method and composition of the first cooking liquor were the same as in Example 5, and the addition of the quinone compound was performed in the same manner as in Example 11. The first cooking liquor added at the top of the kettle was made up to 100% by weight sulfur and 70% by weight of effective alkali relative to the total amount introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor composed mainly of sodium hydroxide was added so as to be 21.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digestion washing zone, a liquid having the same composition as the second cooking liquor was added so as to have an effective alkali content of 8.4% by weight based on the total amount introduced into the cooking system. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the digestion washing zone are alkaline solutions mainly composed of sodium hydroxide generated at the cathode by electrolysis. used. Table 7 shows the cooking results. According to this example, as compared with Comparative Examples 2 and 9 to 11, kappa monovalent at the same effective alkali addition rate was reduced and pulp yield at the same strength brim was increased.

<Comparative Example 1>

Chips used for cooking, total effective alkali addition rate, liquid ratio, Production method, composition, digester temperature, time, H-factor and addition of quinone compound were carried out in the same manner as in Example 1. The first cooking liquor added at the top of the kettle was made to have a sulfur content of 53% by weight and an effective amount of 50% by weight based on the total amount introduced into the cooking system. From the upper extraction strainer, 15% by volume of the whole digested black liquor was extracted. In the upper cooking zone, a second cooking liquor of 30% sulphide was added in an amount of 21.6% by weight of effective alkali to the total amount introduced into the cooking system. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquid having a sulfuration degree of 30% was added so that an effective amount of 8.4% by weight based on the total amount introduced into the cooking system was obtained. Table 3 shows the cooking results.

<Comparative Example 2>

 Chips used for cooking, total effective addition rate, liquid ratio, method and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, temperature, time and H-factor of digester One was performed in the same manner as in Example 1. The first cooking liquor added at the top of the kettle was added so as to have a sulfur content of 53% by weight and an effective aluminum content of 50% by weight based on the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor with a sulphidity of 3096 was added so as to give an effective alkali of 11.6% by weight, based on the total amount introduced into the cooking system. At the bottom of the digestion zone, a liquid having the same composition as the second cooking liquor having a sulfuration degree of 30% was added so as to have an effective alkali content of 8.4% by weight based on the total amount introduced into the cooking system. . The quinone compound was used without addition. Table 3 shows the cooking results.

<Comparative Example 3>

Chips used for cooking, total available alkali addition rate, liquid ratio, preparation and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, temperature, time, H-factor and The quinone compound was added in the same manner as in Example 1. The first cooking liquor added at the top of the kettle was added so as to have a sulfur content of 82% by weight and an effective energy of 80% by weight based on the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor of 30% sulphide is added to make 16.6% by weight of available alkali, based on the total amount introduced into the cooking system. Was. At the bottom of the digestion wash zone, a liquor of the same composition as the second digestion liquor with a 30% sulphide content was added so as to give an effective alkali content of 3.4% by weight, based on the total amount introduced into the digestion system. Table 3 shows the cooking results.

 <Comparative Example 4>

 Chips used for cooking, total available alkali addition rate, liquid ratio, preparation and composition of first cooking liquor, amount of black liquor extracted from upper extraction strainer, temperature, time, H-factor and The quinone compound was added in the same manner as in Example 1. The first cooking liquor added at the top of the kettle was added so as to have a sulfur content of 32% by weight and an effective energy of 30% by weight based on the total amount introduced into the cooking system. At the bottom of the digestion zone, a second cooking liquor with a 30% sulphide degree was added so as to give an effective alkali of 41.6% by weight, based on the total amount introduced into the cooking system. In the lower cooking zone, a liquor of the same composition as the second cooking liquor with a sulphidity of 30% was added so as to give an effective alkali content of 28.4% by weight based on the total amount introduced into the cooking system. Table 3 shows the cooking results.

<Comparative Example 5>

 The chips used in the digestion and the total effective alkali addition rate, liquid ratio, digester temperature, time, H-factor and quinone compound addition were the same as in Example 9; The composition was the same as in Example 1. The first cooking liquor added at the top of the kettle was added so as to have a sulfur content of 53% by weight and an effective aluminum content of 50% by weight based on the total amount introduced into the cooking system. From the upper extraction strainer, 15% by volume of the whole digested black liquor was extracted. At the bottom of the digestion zone, a second cooking liquor with a sulfidity of 30% was added so as to be 31.6% by weight of the effective alkali with respect to the total amount introduced into the cooking system. In the lower cooking zone, a liquid having the same composition as the second cooking liquor having a sulfuration degree of 30% was added so as to have an effective alkali content of 18.4% by weight based on the total amount introduced into the cooking system. . Table 5 shows the cooking results.

<Comparative Example 6>

Chips used in cooking and total effective alkali addition rate, liquid ratio, top extraction The amount of black liquor extracted from the trainer, the temperature, time and H-factor of the digester were the same as in Example 9, and the production method and composition of the first cooking liquor were the same as in Example 1. . The first cooking liquor added at the top of the kettle was added so as to have a sulfur content of 53% by weight and an effective energy of 50% by weight based on the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor of 30% sulphide was added to make 31.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digestion washing zone, a liquid of the same composition as the second digestion liquor with a 30% sulphide degree is used so that the effective amount of liquid is 18.4% by weight based on the total amount introduced into the digestion system. Was added. Quinone compound added to the digester is Te Torahi mud en Torakino emissions, obtained by mixing 0. 0 3 by weight _^0/0 for bone dry chip to a first cooking liquor. Table 5 shows the cooking results.

<Comparative Example 7>

 Examples of the chips used for cooking and the total effective alkali addition rate, liquid ratio, amount of black liquor extracted from the upper extraction strainer, temperature and time of the digester, addition of H-factor and quinone compound In the same manner as in Example 9, the production and composition of the first cooking liquor were performed in the same manner as in Example 1. The first cooking liquor added at the top of the kettle was added so as to have a sulfur content of 82% by weight and an effective energy of 80% by weight based on the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor of 30% sulphide was added to give 16.6% by weight of effective alkali, based on the total amount introduced into the cooking system. At the bottom of the digestion washing zone, a liquid having the same composition as the second cooking liquor having a sulfuration degree of 30% was added so as to have an effective amount of 3.4% by weight based on the total amount introduced into the digestion system. . Table 5 shows the cooking results.

<Comparative Example 8>

Chips used in cooking and total effective alkali addition rate, liquid ratio, amount of black liquor extracted from upper extraction strainer, temperature and time of digester, H-factor and quinone compounds The addition was performed in the same manner as in Example 9 except for the method of preparing the first cooking liquor, The formation was performed in the same manner as in Example 1. The first cooking liquor added at the top of the kettle was added so as to be 32% by weight of sulfur and 30% by weight of effective alkali with respect to the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor of 30% sulphide was added to make up 41.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the cooking washing zone, a liquid of the same composition as the second cooking liquor with 30% sulphide makes up a total of 28.4% by weight of the total amount of liquid introduced into the cooking system. Was added. The cooking results are shown in Table 5.

<Comparative Example 9>

The chips used in the cooking, the total effective addition rate, the liquid ratio, the production method, the composition, the temperature and time of the digester, and the H-factor of the first cooking liquor were the same as in Example 1; The compound was added in the same manner as in Example 11. First cooking liquor added at the top of the kettle, was set to 5 3 weight _^0/0 of sulfur content and 5 0% by weight of the active Al force Li based on the total amount introduced into the digester system. From the upper extraction strainer, 15 volumes 6 of the whole digested black liquor were extracted. At the bottom of the upper cooking zone, a second cooking liquor of 30% sulphide was added to make up 21.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digestion zone, a liquid having the same composition as the second cooking liquor having a sulfuration degree of 30% was added so as to be 8.4% by weight of the effective alkali with respect to the total amount introduced into the cooking system. Table 8 shows the cooking results.

<Comparative Example 10>

The chips used for the cooking, the total effective addition rate, the liquid ratio, the production method, composition, digester temperature, time and H-factor of the first cooking liquor were the same as in Example 1, and the quinone compound The addition was performed in the same manner as in Example 11. First cooking liquor added at the top of the kettle were added to the total amount to be introduced into the cooking system such that the 8 2 weight _^0/0 of sulfur content and 8 0 wt% of effective alkali. At the bottom of the upper cooking zone, a second cooking liquor of 30% sulphide is fed to the digester To 16.6% by weight of the effective alkali. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquor with a sulfuration degree of 30% was added so as to have an effective alkali content of 3.4% by weight based on the total amount introduced into the cooking system. did. Table 8 shows the cooking results.

 Comparative Example 1 1>

 The chips used for the cooking, the total effective addition rate, the liquid ratio, the preparation method, composition, digester temperature, time, and H—factor of the first cooking liquor were the same as in Example 1; The addition was performed in the same manner as in Example 11. The first cooking liquor added at the top of the kettle was added so as to be 32% by weight of sulfur and 30% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the upper cooking zone, a second cooking liquor with a sulphidity of 3096 was added to make up 41.6% by weight of effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digester zone, a liquid of the same composition as the second cooking liquor with a 30% sulphide content is converted to 28.4% by weight of the effective amount of liquid based on the total amount introduced into the cooking system. It was added so that Table 8 shows the cooking results.

<< Example 1 9>

 The chips used for the cooking and the total effective addition rate were set as in Example 1. The cooking equipment used was a 2.5 L capacity auto-crepe that turned upside down in an air bath where an arbitrary temperature profile could be set. The apparatus has a valve that can extract the liquid in the autoclave and a valve that can inject the liquid into the autoclave from outside. Explaining the cooking temperature profile, cooking starts at room temperature, rises to 140 ° C in 30 minutes, and then to 160 ° C in 60 minutes, and then The mixture was kept at 160 ° C. for 50 minutes and digested to H—factor 140.

At the start of the digestion, an alkaline solution mainly composed of sodium hydroxide and sodium sulfide was introduced into the electrolytic cell as the first digestion liquid together with the chips at room temperature. Polysulfuride sulfur concentration obtained by electrochemically oxidizing sodium sulfide in solution 4 g / L (sulfur conversion), sodium hydroxide concentration _{7 0 g ZL (N a 2} 0 equivalent) and sulfide Na Application Benefits um concentration 2 2. 6 g ZL (N a 2 0 equivalent) and alkali resistant cooking liquor containing Porisarufuai de of the main component, introduced into the cooking system The sulfur content and the effective alkali content of 53% by weight and 50% by weight, respectively, were added to the total amount, and the temperature was raised. At that time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips by combining with the moisture brought in by the chips.

When the temperature reached 140 ° C. in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, a second cooking liquor having a sulfidity of 30%, which has been preliminarily heated to 90 ° C, is treated with an effective amount of 31.6% by weight based on the total amount introduced into the cooking system. It was added so that the liquid ratio in the digester was 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfide degree of 30%, which had been heated to 90 ° C in advance, was introduced into the cooking system. To 18.4% by weight of an effective alkali. Onboard in as the compound, Te preparative Rahi Doroan preparative Rakino down the 1, 4, 4 a, 9 a chromatography Te preparative Rahi Doroan 0 bets Rakino down against the bone-dry chip. 0 5 wt _^0/0 of the second To the cooking liquor. Table 9 shows the cooking results. According to the present example, as compared with Comparative Examples 12 to 15, the pulp monovalent value at the same effective power addition rate was reduced, and the pulp yield at the same effective monovalent value was increased.

<< Example 20 >>

The chips used in the cooking, the total effective addition rate were the same as in Example 1, and the cooking equipment, the preparation method of the first cooking liquor, the composition, the cooking temperature, the time, the H-factor and the addition of the quinone compound Was performed in the same manner as in Example 19. At the start of cooking, at room temperature, the first cooking liquor is added together with chips so as to have a sulfur content of 72% by weight and an effective amount of 70% by weight based on the total amount introduced into the cooking system. Then, heating was started. At this time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips by combining the moisture brought in with the chips. When the temperature reached 140 ° C. in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, a second cooking liquor having a sulfidity of 30%, which had been heated to 90 ° C in advance, was supplied with 21.6% by weight of an effective aluminum liquor based on the total amount introduced into the cooking system. Inside the digester Was added so that the solution ratio became 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfide degree of 30%, which had been heated to 90 ° C in advance, was introduced into the cooking system. Was added to make 8.4% by weight of the effective amount based on the total amount of the active alkali. Table 9 shows the cooking results. According to the present example, as compared with Comparative Examples 12 to 15, the monovalent value of copper at the same effective alkali addition rate was reduced, and the pulp yield at the same effective monovalent value of pulp was increased. << Example 2 1>

 The chips used for the cooking, the total effective addition rate were the same as in Example 1, and the cooking equipment, the preparation method of the first cooking liquor, the composition, the cooking temperature, the time, the H-factor and the addition of the quinone compound were This was performed in the same manner as in Example 19. At the start of the cooking, at room temperature, the first cooking liquor, together with the chips, should have a sulfur content of 100% by weight and an effective energy of 50% by weight, based on the total amount introduced into the cooking system. The mixture was added, and the temperature was raised. At that time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dried chips by combining the moisture brought in with the chips. When the temperature reached 140 ° C. in 30 minutes after the start of the temperature rise, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, a second cooking liquor containing sodium hydroxide as a main component, which has been preheated to 90 ° C, is mixed with 31.6% by weight of an effective alkali based on the total amount introduced into the cooking system. Was added so that the liquid ratio in the digester became 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfuration degree of 30%, which was previously heated to 90 ° C, was introduced into the cooking system. It was added so as to be 18.4% by weight of effective alkali with respect to the total amount. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the digestion washing zone used an alkaline solution mainly composed of sodium hydroxide produced at the cathode by electrolysis. . Table 9 shows the cooking results. According to this example, as compared with Comparative Examples 12 to 15, kappa monovalent at the same effective alkali addition rate was reduced, and pulp yield at the same kappa monovalent was increased.

<< Example 2 2 >>

The chips used for cooking, the total effective addition rate were the same as in Example 1, The cooking apparatus, the method for preparing the first cooking liquor, the composition, the cooking temperature, the time, the H-factor and the addition of the quinone compound were carried out in the same manner as in Example 19. Cooking start at room temperature, the chip and the monitor, 1 0 0 wt _^0/0 of sulfur and 7 0 wt _^0/0 of the effective Al force Li based on the total amount introduced the first cooking liquor in digester system And heating was started. At that time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips, together with the moisture brought in by the chips. When the temperature reached 140 at 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, a second cooking liquor containing sodium hydroxide as a main component, which had been heated to 90 ° C in advance, was used as an effective alcohol in an amount of 21.6% by weight based on the total amount introduced into the cooking system. Potash was added so that the liquid ratio in the digester was 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfuration degree of 30%, which was previously heated to 90 ° C, was introduced into the cooking system. It was added to make 8.4% by weight of effective alkali based on the total amount. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the cooking washing zone used an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. Table 9 shows the cooking results. According to this example, as compared with Comparative Examples 12 to 15, the zipper value was reduced at the same effective power addition rate, and the pulp yield was increased at the same effective pressure.

<< Example 2 3 >>

The chips used for the cooking and the total effective addition rate were the same as in Example 1, and the cooking equipment, the cooking temperature and time, and the addition of H-factor and quinone compound were the same as in Example 19. I went. The chips used for the digestion and the total effective addition rate were set in the same manner as in Example 1. The digester used an autoclave with a capacity of 2.5 L, which was turned upside down in an air bath in which an arbitrary temperature profile could be set. This device also has a valve that can extract the liquid in the autoclave and a valve that can inject the liquid from outside into the autoclave. To explain the temperature profile of cooking, the cooking started at room temperature, heated to 140 ° C in 30 minutes, and further heated to 160 ° C in 60 minutes. Thereafter, the temperature was maintained at 160 ° C. for 250 minutes, and the digestion was carried out until H—factor 140.

At the start of the cooking, at room temperature, together with the chips, an alkaline solution containing sodium hydroxide and sodium sulfide as main components was introduced into the electrolytic cell as a first cooking liquid, Porisarufai Dosarufu § concentration sulfide Na birds um obtained by electrochemical oxidation of the Al force Li solution in 1 0 g / L (terms of sulfur), hydroxide Na preparative potassium concentration 7 0 gZL (N a ₂ 0 equivalent) and sulfide Na Application Benefits um concentration 1 1 / L (N a ₂ 0 equivalent) alkaline cooking liquor of the main component, 5 5 wt% of sulfur based on the total amount to be introduced into the cooking system and 5 0% , And the temperature was started. At that time, the liquid ratio was adjusted to 2.5 LZkg with respect to the absolutely dry chips by combining with the moisture brought in by the chips.

 When the temperature reached 140 ° C. in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, the second cooking liquor having a sulfuration degree of 30%, which had been preheated to 90%, was digested with 31.6% by weight of an effective alkali based on the total amount introduced into the cooking system It was added so that the liquid ratio in it became 2.5 LZ kg. Further, at 240 minutes from the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfide degree of 30%, which has been heated to 90 ° C in advance, is introduced into the cooking system. It was added so that the effective alkali was 18.4% by weight based on the total amount. As the quinone compound, tetrahydroanthraquinone was mixed with the second cooking liquor in an amount of 0.05% by weight based on the dry chips. Table 10 shows the results of the cooking. According to this example, as compared with Comparative Examples 16 to 19, the kappa monovalent at the same effective alkali addition rate was reduced, and the pulp yield at the same kappa monovalent was increased.

<< Example 24 >>

The chips used for the cooking and the total effective addition rate were the same as in Example 1, and the cooking equipment, the cooking temperature and time, the addition of the H-factor and the quinone compound were the same as in Example 19. The production method and composition of the first cooking liquor were performed in the same manner as in Example 23. At the start of cooking, at room temperature, the first cooking liquor with chips Sulfur content of 70% by weight and effective alkali of 70% by weight were added to the total amount introduced into the digestion system, and the temperature was raised. At that time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips, in combination with the moisture brought in by the chips. When the temperature reached 140 ° C. in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, a second cooking liquor having a sulfidity of 30%, which has been heated to 90 ° C in advance, is used to digest 21.6% by weight of the effective alkali with respect to the total amount introduced into the cooking system. It was added so that the liquid ratio in the kettle became 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid with a sulfuration degree of 30%, which was previously heated to 90 ° C, was introduced into the cooking system. 8.4% by weight based on the total weight of the solution. Table 10 shows the results of the cooking. According to the present embodiment, the power value at the same effective alkali addition rate is reduced as compared with Comparative Examples 16 to 19, and the same force is obtained. No, in monovalent. The rup yield was increased.

 << Example 25 >>

The chips used for cooking and the total effective addition rate were the same as in Example 1, and the digester, cooking temperature, time, addition of H-factor and quinone compound were the same as in Example 19. The preparation and composition of the first cooking liquor were carried out in the same manner as in Example 23. At the start of the cooking, the first cooking liquor is added together with the chips at room temperature so as to have a sulfur content of 100% by weight and an effective alkali of 50% by weight with respect to the total amount introduced into the cooking system. Warm was started. At this time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips, in combination with the moisture brought in by the chip. When the temperature reached 140 ° C. in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, the second cooking liquor mainly composed of sodium hydroxide preheated to 90 ° C. was added in an amount of 31.6% by weight based on the total amount introduced into the cooking system. Effective alkali was added so that the liquid ratio in the digester was 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfide degree of 30%, which was previously heated to 90 ° C, was introduced into the cooking system. Add 18.4% by weight of effective alkali to the total amount. Was. The second cooking liquor to be added at the bottom of the upper cooking zone and the cooking liquor to be added at the bottom of the cooking and washing zone used alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. Table 10 shows the cooking results. According to this example, as compared with Comparative Examples 16 to 19, the kappa value at the same effective alkali addition rate was reduced, and the pulp yield at the same power value was increased.

 << Example 26 >>

 The chips used for the cooking and the total effective addition rate were the same as in Example 1, and the cooking equipment, the cooking temperature, time, H-factor and the addition of the quinone compound were the same as in Example 19. The preparation and composition of the cooking liquor of No. 1 were carried out in the same manner as in Example 23. At the start of the cooking, the first cooking liquor was added together with the chips at room temperature so as to give a sulfur content of 100% by weight and an effective alkali of 70% by weight based on the total amount introduced into the cooking system. The heating was started. At that time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chip by combining with the water brought in by the chip. When the temperature reached 140 ° C. in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, the second cooking liquor mainly composed of sodium hydroxide preheated to 90 ° C was used in an amount of 21.6% by weight based on the total amount introduced into the cooking system. Alkali was added so that the liquid ratio in the digester was 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid with a sulfuration degree of 30%, which had been heated to 90 in advance, was introduced into the cooking system. To 8.4% by weight of the effective alkali. The second cooking liquor added at the bottom of the upper cooking zone and the cooking liquor added at the bottom of the cooking washing zone used an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis. . Table 10 shows the results of the cooking. According to this example, as compared with Comparative Examples 12 to 15, the monovalent value of pulp at the same effective alkali addition rate was reduced, and the pulp yield at the same monovalent value of pulp was increased.

<Example 27>

Chips used for cooking, total effective alkali addition rate, liquid ratio, amount of black liquor extracted from upper extraction strainer, digester temperature, time, H-factor and The quinone compound was added in the same manner as in Example 1. The first cooking liquor to be added at the top of the kettle is obtained by previously dissolving sulfur at 70 ° C in an alkaline solution containing sodium hydroxide and sodium sulfide as main components. was policer Rufuai Dosarufa concentration 4 g / L (terms of sulfur), 0 hydroxide Na Application Benefits um concentration _{7 g / L (N a 2} 0 equivalent) and sulfide Na Application Benefits um concentration 3 0 g / L (N a 2 0 (Calculated) of alkaline cooking liquor was added so as to have a sulfur content of 56% by weight and an effective aluminum content of 50% by weight based on the total amount introduced into the cooking system. At that time, the liquid ratio was adjusted to about 3.5 L / kg with respect to the absolutely dry chips, in combination with the moisture brought into the chips. From the upper extraction strainer, 45% by volume of the whole digested black liquor was extracted. In the upper cooking zone, a second cooking liquor with a sulphidity of 30% was added to make 31.6% by weight of the effective alkali with respect to the total amount introduced into the cooking system. At the bottom of the digestion-washing zone, a liquid having the same composition as the second cooking liquor having a sulfidity of 30% was added so that the effective alkali was 18.4% by weight based on the total amount introduced into the cooking system. Table 12 shows the results of the cooking. According to this example, as compared with Comparative Examples 16 to 19, the kappa monovalent at the same effective alkali addition rate was reduced and the pulp yield at the same kappa monovalent was increased.

<< Example 28 >>

Chips used for cooking, total effective alkali addition rate, liquid ratio, amount of black liquor extracted from upper extraction strainer, temperature and time of digester, addition of H_factor and quinone compound Was performed in the same manner as in Example 1. The first cooking liquor to be added at the top of the kettle was prepared by previously dissolving sulfur at 70 ° C in an alkaline solution mainly containing sodium hydroxide and sodium sulfide. resulting policer Rufuai de concentration 1 0 GZL (terms of sulfur), hydroxide Na Application Benefits um concentration 7 0 gZ L (N a ₂ 〇 equivalent) and sulfide Na Application Benefits um concentration 3 0 g / L (N a 2 0 in terms of ) Was added so as to have a sulfur content of 100% by weight and an effective aluminum content of 50% by weight based on the total amount introduced into the cooking system. In the upper cooking zone, 31.6% by weight of the second cooking liquor, mainly composed of sodium hydroxide, based on the total amount introduced into the cooking system is used. It was added so as to be alkaline. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquor, mainly composed of sodium hydroxide, becomes 18.4% by weight of effective alkali with respect to the total amount introduced into the cooking system. Was added. For the second cooking liquor added at the bottom of the upper cooking zone and the cooking liquor added at the bottom of the digestion washing zone, an alkaline solution mainly composed of sodium hydroxide generated at the cathode by electrolysis was used. Table 12 shows the results of the cooking. According to this example, as compared with Comparative Examples 16 to 19, kappa monovalent at the same effective alkali addition rate was reduced, and pulp yield at the same kappa monovalent was increased.

<Comparative Example 1 2>

 The chips used for the cooking, the total effective addition rate were the same as in Example 1, and the cooking equipment, preparation method, composition, cooking temperature, time, H-factor and quinone compound of the first cooking liquor were used. Was added in the same manner as in Example 19. At the start of the cooking, the first cooking liquor was added together with the chips at room temperature so that the sulfur content was 53% by weight and the effective amount of 50% by weight based on the total amount introduced into the cooking system. Warm was started. At that time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips by combining with the moisture brought in by the chips. When the temperature reached 140 in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After extraction, a second cooking liquor of 30% sulphide, previously heated to 90 ° C, was treated with 31.6% by weight of an effective aluminum liquor based on the total amount introduced into the digestion system. Was added so that the liquid ratio in the digester became 2.5 L / kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfide degree of 30%, which had been heated to 90 ° C in advance, was introduced into the cooking system. Was added so as to be 18.4% by weight of the effective alkali with respect to the total amount of the alkali. Table 11 shows the results of the cooking.

<Comparative Example 13>

The chips used for the cooking and the total effective addition rate were the same as in Example 1, and the cooking equipment, the production method, the composition, the cooking temperature, the time and the H-factor of the first cooking liquor were the same as in Example 1. Performed in the same manner as 9. At the start of the cooking, at room temperature, the first cooking liquor together with the chips was 53% by weight of sulfur, based on the total amount introduced into the cooking system. It was added so as to have a yellow content and an effective amount of 50% by weight, and heating was started. At that time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips, in combination with the moisture brought in by the chips. When the temperature reached 140 ° C. in 30 minutes after the start of heating, 45% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, a second cooking liquor consisting mainly of sodium hydroxide, which had been preheated to 90, was added with 31.6% by weight of an effective alkali based on the total amount introduced into the cooking system. The liquid ratio in the digester was 2.5 LZ kg. Further, at 240 minutes after the start of the cooking, a liquid having the same composition as the second cooking liquid having a sulfuration degree of 30%, which was previously heated to 90 ° C, was introduced into the cooking system. 18.4% by weight based on the total amount of effective alkali. The quinone compound was not added. Table 11 shows the results of the cooking.

Comparative Example 1 4>

 The chips used for the cooking, the total effective addition rate were the same as in Example 1, and the cooking equipment, the preparation method of the first cooking liquor, the composition, the cooking temperature, the time, the H-factor and the addition of the quinone compound were This was performed in the same manner as in Example 19. At the start of the cooking, the first cooking liquor is added together with the chips at room temperature so as to have a sulfur content of 82% by weight and an effective energy of 80% by weight based on the total amount introduced into the cooking system. Warm was started. At this time, the liquid ratio was adjusted to 2.5 LZ kg with respect to the absolutely dry chips by combining with the moisture brought in by the chips. When the temperature reached 140 ° C in 30 minutes after the start of heating, 15% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, a second cooking liquor consisting mainly of sodium hydroxide, which had been preheated to 90 ° C., was added in an amount of 16.6% by weight based on the total amount introduced into the cooking system. Effective alcohol was added so that the liquid ratio in the digester was 2.5 LZ kg. Further, at 240 minutes after the start of cooking, a liquid having the same composition as the second cooking liquid with a sulfuration degree of 30%, which had been heated to 90 ° C in advance, was introduced into the cooking system. It was added so as to obtain 3.4% by weight of effective alkali with respect to the total amount to be prepared. Table 11 shows the results of the cooking.

Comparative Example 1 5> The chips used for the cooking, the total addition rate of the effective amount were the same as in Example 1. Was performed in the same manner as in Example 19. At the start of the cooking, the first cooking liquor was added together with the chips at room temperature so as to be 32% by weight of sulfur and 30% by weight of an effective alkali with respect to the total amount introduced into the cooking system. Started. At this time, the liquid ratio was adjusted to 2.5 L / kg with respect to the absolutely dry chips, in combination with the moisture brought in by the chips. When the temperature reached 140 in 30 minutes after the start of heating, 15% by volume of the whole digested black liquor was extracted from the autoclave. After the extraction, the second cooking liquor containing sodium hydroxide as a main component, which had been preliminarily heated to 90 ° C., was added in an amount of 41.6% by weight based on the total amount introduced into the cooking system. Effective alcohol was added so that the liquid ratio in the digester was 2.5 LZ kg. Further, at 240 minutes after the start of cooking, a liquid having the same composition as the second cooking liquid with a sulfuration degree of 30%, which had been heated to 90 ° C in advance, was introduced into the cooking system. It was added so as to be 18.4% by weight of the effective alkali with respect to the total amount to be prepared. Table 11 shows the results of the cooking.

 <Comparative Example 16>

 The chips used in the digestion, the total effective alkali addition rate, the liquid ratio, the temperature and time of the digester, the addition of the H-factor and the quinone compound were the same as in Example 1, except that the first digestion liquid was used. The production method and composition were the same as in Example 27. The first cooking liquor added at the top of the kettle was such that it had a sulfur content of 56% by weight and an effective aluminum content of 50% by weight, based on the total amount introduced into the cooking system. From the upper extraction strainer, 15% by volume of the total digested black liquor was extracted. In the upper cooking zone, a second cooking liquor of 30% sulphide was added to give an effective total of 21.6% by weight, based on the total amount introduced into the cooking system. At the bottom of the digestion zone, a liquid of the same composition as the second cooking liquor with 30% sulphide is used, based on the total amount introduced into the cooking system. 4% by weight of effective alkali was added. Table 13 shows the cooking results.

Comparative Example 1 7> The chips used for cooking, the total effective alkali addition rate, the liquid ratio, the temperature, time and H-factor of the digester were the same as in Example 1, and the production method and composition of the first cooking liquor were the same as in Example 27. The same was done. The first cooking liquor, which was added at the top of the kettle, was added so as to have a sulfur content of 56% by weight and an effective alkali of 50% by weight based on the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor of 30% sulphide was added to give an effective alkali of 11.6% by weight, based on the total amount introduced into the cooking system. At the bottom of the digestion washing zone, a liquid having the same composition as the second cooking liquor having a sulfuration degree of 30% was added so as to have an effective alkali content of 8.4% by weight based on the total amount introduced into the digestion system. The quinone compound was not added. Table 13 shows the results of the cooking.

 <Comparative Example 18>

 The chips used in the cooking, the total effective alkali addition rate, the liquid ratio, the temperature and time of the digester, the addition of the H-factor and the quinone compound were the same as in Example 1, and the method and composition of the first cooking liquor were used. Was performed in the same manner as in Example 27. The first cooking liquor, which was added at the top of the kettle, was added so as to have a sulfur content of 83% by weight and an effective alkalinity of 80% by weight based on the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor of 30% sulphide was added to make up 16.6% by weight of available alkali, based on the total amount introduced into the cooking system. At the bottom of the cooking washing zone, a liquid having the same composition as the second cooking liquor with a sulfuration degree of 30% becomes an effective amount of 3.4% by weight of the total amount introduced into the cooking system. Was added. Table 13 shows the results of the cooking.

<Comparative Example 19>

The chips used in the digestion, the total effective alkali addition rate, the liquid ratio, the temperature and time of the digester, the addition of the H-factor and the quinone compound were the same as in Example 1; The production method and composition were the same as in Example 27. The first cooking liquor added at the top of the kettle was added so as to be 46% by weight of sulfur and 30% by weight of effective alkali with respect to the total amount introduced into the cooking system. In the upper cooking zone, a second cooking liquor of 30% sulphide is added to the total amount introduced into the cooking system. To 41.6% by weight. The cooking Arai诤zone bottom liquid of the same composition as the second cooking liquor sulfidity 3 0% to 2 8.4 effective Al force Li content of weight _^0/0 relative to the total amount to be introduced into the cooking system Was added so that Table 13 shows the results of the cooking.

table 1

Table 3

Table 4

Table 5 Example · Comparative fe NO.I Comparative example 5 mm 1 Comparative example 7 Comparative example 8 Wood chips 1 Hardwood mixed material Hardwood mixed material 1 Hardwood mixed material Hardwood mixed material Total effective Al or J addition rate (vs. 'Weight X: as Na20) 11.9 12.8 13.6 11.9 12.8 13.6 Π.9 12.8 is added 6 I 11.9 12.8 13.6

 Alkali polysulfate in cooking liquor W 'concentration I 4 ""-4 4 Effective aluminum splitting ratio to total amount introduced into cooking system (weight) 50 50 80 30

3 Effective alkali J addition rate Dried チ Weight 6.0 6.4 6.8 6.0 6.4 6.8 1 9.5 10.2 10.9 3.6 3.8 4.1 硗 yellow fraction ratio to the total amount introduced into the digester (weight X) 53 53 1 82 32

16 'Quinone compound

 Quinono compound Kahan (compared to 7 weight x)

 Upper extraction 24 All § Ratio of extracted black liquor to black liquor (to total black liquor 稹) 15 45 1 45 45

 Effective alkali splitting ratio to the total amount introduced into the digestion system (weight X) 31.6 31.6 16.6 41.6

8 Yes Ji! I Al or J added half (vs. dry weight) s 3.8 4.0 4.3 3.8 4.0 4.3 2.0 2.1 2.3 5.0 5.3 5.7

 nil, 30 30 30 30

16 Quinone compound M, 4a, 9a-Dry [3 anthraquin / l, 4,4a, 9a- † l> La! : Anthraquinone l, 4, ¼9a-tide port Anthranquinone compound addition rate (½dry weight x) 0.03 0 0.03 0.03 Lower extraction 26 Ratio of extracted black liquor to total black liquor (total black liquor volume) i) 85 55 55 55

 Effective Al to Total Introduced into Cooking System J Ratio (Weight X) 18.4 18.4 3.4 28.4

9 Effective Alkali or J addition rate (vs. absolutely dry Chi'Noff 'weight X) 2.2 2.3 2.5 2.2 2.3 2.5 0.4 0.4 0.5 3.4 3.6 3.9 Degree of oxidation (X) 30 30 30 30

H-factor 830 830 B30 830 Pulp yield W 54.0 52.7 52.0 54.1 52.7 52.2 I 54.1 52.5 52.2 54.2 52.5 51.5 Digestion results Kampa 29.1 21.5! 8.8 26.3 20.5 16.2 25.2 20.0 18.5 30.3 23.1 19.0 Valve yield at kappa price 20 Rate (X) 52.3 52.5 52.5 51.7

N, AQ pot top added

Table 6 Example 'Comparative Example No. 1 Example 11 Example ¾ Example 12 1 Example K Example 13 Example 14

 Wood chip 1 Needle 1! Mixed material Softwood mixed it 1 Needle mixed material Steel mixed material Total effective alkali addition rate (as absolutely dry Chikufu 'weight V Na20) 1 14.5 16.5 18.5 14.5 16.5, 8.5 I 14.5 16.5 18.5 14.5 16.5 IB.5 Addition ■ Extraction location I

 Alkaline or J-type steam Φ polysulfur (黧 g / l) 4 4 4 4 Effective alkali splitting ratio to total amount introduced into digester (weight X) 50 70 50 70

3 Effective Al addition rate (based on absolute dry weight) J) 7.3 8.3 9.3 10.2 11.6 13.0 7.3 8.3 9.3 10.2 11.6 13.0 Yellow fraction ratio (weight) 53 72 100 100

16 'Quinone compound 1,4 a, 9a- 卄 La t Qan 1 · laki l, 4.4a.9a- † Tra t D Anthraquinone 1, a.9a- La t D ア ン an 1 ラ Raki / n Addition rate of quinone compound (¾ absolute dry weight);) 0.05 0.05 0.05 0.05 Upper extraction 24 All Extraction black liquor ratio (to total black liquor volume H) 45 45 45 45

 Effective alkali splitting ratio to total amount introduced into digester (weight) 1) 31.6 21.6 31.6 21.6

8 Effective alkali addition rate (vs. dry weight) 4.6 5.2 5.8 3.1 3.6 4.0 4.6 5.2 5.8 3.1 3.6 4.0

 (Degree of change) 30 30 0 0

 16 Quinone compounds

 Quinone compound addition rate (to weight of female chick! 0 0 0 0 Lower extraction 26 Sodeide Kuromae vs. total black liquor X for total steaming) 1 55 55 55 55

 Total tl introduced into the digestion system: effective alka or J split ratio (weight << 18.4 8.4 18.4 8.4

9 Effective Alkali or J addition rate (vs. absolutely dry chikufu 'weight X) 2.7 3.0 3.4 1.2 1.4 1.6 2.7 3.0 3.4 1.2 1.4 1.6 瞧) 1) 30 30 0 0

H-factor-1 1 1400 1400 1400 1400 Valve yield (X) I 47.4 46.1 45.5 47.8 46.6 46.0 47.1 46.2 45.6 47.2 46.4 45.5 Cooking result Kappa monovalent 29.5 25.0 23.2 29.8 25.2 22.9 27.1 24.1 22.3 28.7 25.2 22.5 Kappa Valve yield in HS25 Rate (X) 46.2 46.6 «.5 46.4

Table 7

Table 8 Example 'Comparative Example No. 1 Comparative Example 9 Comparative Example 10 1 Comparative Example 11 Wood Chip 1 Softwood Mixed Material Softwood Mixed Material 1 麵 Mixed Material Total Effective Alkali Addition Rate Dry Dough' Weight Na20) 1 14.5 16.5 18.5 14.5 16.5 1B.5 I 14.5) 6.5 18.5 Addition, extraction location B

Alkaline porph ₇ I

 J 卄 ΓίΚϋιΛβ 4 4 4

¾ Enter 孴 Dimensions ^ Right Alli ⁴ min iltH ¾ d 50 80 30

3 Effective alkali addition rate (absolutely dry chikufu 'weight) 7.3 8.3 9.3 11.6 13.2 H.6 4.4 5.0 5.6 Ratio of splitting of cannabis to total amount introduced into digester (weight) 53 82 32

16 'quinone compound M, ¼9a-latto'D anthraquinone, 4.4a, 9a-tetrahydroan (· Laquinone U4a, 9a-Utra Dan [· Laquino; / Absolutely dry weight) 0.05 0.05 0.05 Top extraction 24 Ratio of extracted black liquor to total digested black liquor (to total black liquor volume) 15 45 1 45

 Effective alkali to total amount fed to the cooking system λ or J split ratio (weight X) 31.6 16.6 41.6

8 Effective Al or J addition rate (vs. absolute weight X) 4.6 5.2 5.8 2.4 2.7 3.1 6.0 6.9 7.7 Degree of conversion (X) 30 30 30

16 Quinone compounds

 Quinone compound addition ratio (vs. Zhifu's overlap X) 0 0 0 Lower extraction 26 Ratio of black liquor to total black liquor (total black liquor volume X) 1 85 55 55

 Effective Al W split ratio to total amount introduced into digester W (weight) 18.4 3.4 28.4

9 Effective Alkali rate (vs. dry weight) 2.7 3.0 3.4 0.5 0.6 0.6 4.1 4.7 5.3 Image (X) 30 30 30

Η-factor 1 1400 1400 1400 Valve yield 0 1 47.4 46.7 44.9 I 47.4 46.8 45.0 46.5 45.9 44.2 Digestion result Cutlet value 1 37.5 31.5 24.8 1 36.8 30.3 24.5 34.2 24.8 Valve yield at kappa value 25 (X) 45.0 45.2 44.3

Table 9

Table 10

Table 11 Examples · Comparative Examples NO. Comparative Example 12 1 Difficult 1 Hobby 1 1 Comparative Example 15 Wood Chips Blended I I Softwood Blended 1 Blended 1 Needle Blended All Effective Al or J 14.5 16.5 18.5 H.5 16.5 18.5 14.5 16.5 18.5 I 14.5 16.5 18.5 Addition ・ Extraction location

 Polysulphite in alkaline cooking liquor 'concentrated g (g / l) 4 4 4 4 Effective alkali to total λ to be digested J ratio (weight X) 50 50 80 30

3 Effective Al or J addition rate (vs. absolutely dry chikufu 'weight) 7.3 8.3 9.3 7.3 8.3 9.3 11.6 13.2 14.8 4.4 5.0 5.6 Yellow fractionation ratio (Weight ix) to total amount introduced into digester 53 53 82 32

16Quinone compounds

 Addition rate of quinone compound (to female chikufu 'weight) 0 0 0

 Upper extraction 24 Ratio of extracted black liquor to total digested black liquor (to total black liquor volume) i) 15 45 45 45

 Is the effective amount of alkaline available to the total amount introduced into the steam system? Critical to J harm (heavy) 31.6 31.6 16.6 41.6

8 Effective Al or J addition rate (vs. absolute weight X) 1 4.6 5.2 5.8 4.6 5.2 5.8 2.4 2.7 3.1 6.0 6.9 7.7 Degree of oxidation (X) I 30 30 30 30

16 Quinone compound l, 4,9a- 卄 t 'D anthraquinone / l, 4,4a, 9a-teho (·' !! anthraquinone

 Quinone compound addition rate (based on absolute dry chip) 1 0.05 0 0.05 0.05 Lower extraction 26 Ratio of extracted black liquor to total digested black liquor (total black liquor volume X) [85 55 55 55

 Effective Al / J Split Ratio (Weight X) 18.4 18.4 3.4 28.4

9 Effective Al or J addition rate (½dry weight);) 2.7 3.0 3.4 2.7 3.0 3.4 0.5 0.6 0.6 4.1 4.7 5.3 Degree of rumination (X) 30 30 30 30

H-factor 1 1400 1 1400 1400 1400 Valve yield WI 47.6 46.2 45.0 I 46.2 45.1 44.0 47.0 4S.5 44.7 46.B 45.5 44.5 Steamed fruit Kappa monovalent 33.0 26.9 22.0 40.5 31.4 24.5 34.0 27.5 23.4 33.0 30.6 24.6 Kappa mono Price 251: Pulp yield at (X) 45.6 44.4 45.0 44.6

Table 12

Table 13 Example shelves O.I ratio example 16 ratio glue 17 1 listening 8 1 comparative example 19 wood chips I genuine mixed material 1 11 softwood mixed material 1 softwood mixed ίί 1 softwood mixed material 14.5 16.5 18.5 I 14.5 16.5 18.5 I 14.5 16.5 18.5 I 14.5 16.5 18.5

'Ca' extraction site 1 1

 Alkaline leaching, ¾Φ polysulfite 7 '' baho (ί / Ι) 4 I 4 4 4 Effective fraction of total amount introduced into the digester J ratio 50 1 50 80 30

3 Effective alkali addition rate (relative to absolute dry weight S) 7.3 8.3 9.3 7.3 8.3 9.3 11.6 13.2 14.8 4.4 5.0 5.6 Slight yellow fraction of total amount introduced into digester 56 1 56 83 46

16 'Quinone compound

 Quinone compound-added skewers (vs. dry weight) 0 0 0

 Upper extraction 24 Ratio of extracted black liquor to total digested black liquor (to total black liquor volume) 15 45 1 45 ί 45

 Effective Al or J split ratio to total amount introduced into digester (weight X) 31.6 31.6 16.6 4t.6 β Effective Al or J addition rate (vs. ίέDried 'Noff' weight) ί) 4.6 5.2 5.8 4.6 5.2 5.8 2.4 2.7 3.1 6.0 6.9 7.7 t Degree of oxidation (X) 30 30 30 30

 16 Quinone compound 1.93-Te-do-an |> Raki / n M, ¼9a-tetra !: (· 1 · Raki / ン 1.9a-f D-an | · Quinone compound addition rate (舰 Dry 'Weight X) 0.05 0 0.05 0.05 Lower extraction 26 Ratio of extracted black liquor to total digested black liquor (total black liquor) 1) 1 85 1 55 55 1 55

 Effective alkali or total amount of J introduced to the digestion system llj ratio (weight X) 18.4 18.4 3.4 1 28.4

9 Effective Al addition rate (vs. absolute dry weight) 2.7 3.0 3.4 2.7 3.0 3.4 0.5 0.6 0.6 1 4.1 4.7 5.3 Degree of W 30 30 30 [30

H-factor 1400 1 1400 1 1400 1 1400 Valve yield (X) 47.2 46.2 45.0 I 46.7 45.4 44.2 47.4 46.4 45.3 46.9 45.7 44.

Valve yield at Kappa 11525 (H) 45.6 44.6 46.0 45.0

Industrial applicability

 According to the present invention, the pulp yield can be further improved, and the relationship between monovalent kappa and pulp yield can be further improved. That is, according to the present invention, it is possible to reduce the monovalent value of pulp at the same effective alkali addition rate and to improve the pulp yield at the same monovalent value of kappa.

Claims

The scope of the claims 1. Inside the digester from top to bottom, top zone, top digestion zone In addition, a lower cooking zone is provided, a strainer is provided at the bottom of each zone, and the cooking black liquor extracted from at least one of the strainers is discharged out of the cooking system. In a continuous digestion method using a vessel digester, hardwood or softwood chips are used, containing polysulfide sulfur at a concentration of 3 to 20 g ZL as sulfur, and converting into alkaline cooking liquor introduced into the digestion system. The alkaline cooking liquor contains 45 to 100% by weight of sulfur and 45 to 79% by weight of effective total amount of sulfur contained in the total digestion-active sulfur and total alcohol contained. The lignocellulosic material is steamed by adding an alkaline cooking liquor added at the top of the kettle and further containing 0.01 to 1.5% by weight of quinone compound per absolutely dry chip to the digester. solution.  2) The above-mentioned alkaline cooking liquor contains sodium hydroxide and sodium sulfide, and the sodium sulfide in the alkaline solution containing sodium carbonate and sodium sulfide as the main components. The method for cooking a lignocellulosic material according to claim 1, which is an alkaline cooking liquid containing 3 to 20 gL of polysulfide sulfur as the sulfur obtained by electrochemical oxidation.  3. In the continuous digestion method using the 1-vessel digester described above, at least the digested black liquor discharged outside the digestion system is extracted from the strainer at the bottom of the top zone and directly recovered from the digester. 3. The process for digesting lignocellulosic material according to claim 1, wherein 20 to 60% by volume of the total digested black liquor sent to the column is extracted by a strainer at the bottom of the tower top zone. .  4. The method for digesting lignocellulosic material according to any one of claims 1 to 3, wherein a digestion washing zone is further provided below the lower digestion zone. 5. In the digestion process of re Diagnostics cellulosic material according to any one of claims 1 to 4, per absolute dry chips 0. 0 1-0. Containing from 1 5 weight ^0/6 quinone compound of A method for digesting lignocellulosic material, comprising feeding a steam cooking liquor to the top of an infiltration vessel or the bottom of an upper cooking zone. 6. Any Porisarufu § I Dosarufa concentration of Al force Li of cooking liquor that is added at the top of the penetration base Sseru of Motomeko 1-5, characterized in that 8-1 8 ₈ Roh Dearu and sulfur Or the cooking method of lignocellulosic material according to item 1. 7. The alkaline cooking liquor added at the top is 50 to 100% by weight based on the total cooking active sulfur content and the total content of the alkaline cooking liquor introduced into the cooking system. The method for digesting lignocellulosic material according to any one of claims 1 to 6, comprising a digestion active sulfur content and an effective alcohol content of 50 to 60% by weight. main